U.S. patent application number 14/399723 was filed with the patent office on 2015-06-25 for method and apparatus for transceiving data using plurality of carriers in mobile communication system.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to JongSoo Choi, Jae Hyuk Jang, Soeng Hun Kim, Gert Jan Van Lieshout.
Application Number | 20150181593 14/399723 |
Document ID | / |
Family ID | 49550870 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150181593 |
Kind Code |
A1 |
Kim; Soeng Hun ; et
al. |
June 25, 2015 |
METHOD AND APPARATUS FOR TRANSCEIVING DATA USING PLURALITY OF
CARRIERS IN MOBILE COMMUNICATION SYSTEM
Abstract
A method and apparatus of a base station (P-ENB) that controls a
primary cell (PCell) of user equipment (UE) is provided. The method
includes receiving a packet from a serving gateway through a
non-primary (NP)-evolved packet system (EPS) bearer for a serving
cell of a non-P-ENB base station (NP-ENB), generating a first radio
link control packet data unit (RLC PDU) using the received packet,
and transmitting the generated first RLC PDU to the NP-ENB.
Inventors: |
Kim; Soeng Hun; (Suwon-si,
KR) ; Van Lieshout; Gert Jan; (Staines, GB) ;
Jang; Jae Hyuk; (Suwon-si, KR) ; Choi; JongSoo;
(Suwon-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si, Gyeonggi-do |
|
KR |
|
|
Family ID: |
49550870 |
Appl. No.: |
14/399723 |
Filed: |
May 9, 2013 |
PCT Filed: |
May 9, 2013 |
PCT NO: |
PCT/KR2013/004113 |
371 Date: |
November 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61644645 |
May 9, 2012 |
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61645591 |
May 10, 2012 |
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61646888 |
May 14, 2012 |
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61649910 |
May 21, 2012 |
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61653026 |
May 30, 2012 |
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61658617 |
Jun 12, 2012 |
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04W 76/28 20180201;
H04W 72/042 20130101; H04W 56/0005 20130101; H04L 5/0098 20130101;
H04W 24/02 20130101; H04L 5/0032 20130101; H04W 56/0045 20130101;
H04W 48/16 20130101; H04W 4/18 20130101; H04W 72/0426 20130101;
H04W 52/0216 20130101; H04W 76/12 20180201; H04W 76/15 20180201;
Y02D 30/70 20200801; H04W 72/0453 20130101; H04W 52/0241
20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 4/18 20060101 H04W004/18; H04L 5/00 20060101
H04L005/00 |
Claims
1. A communication method of an evolved Node B of controlling a
primary cell (P-ENB) of a User Equipment (UE), the method
comprising: receiving a packet from a serving gateway through a
non-primary Evolved Packet System (NP-EPS) bearer for serving cells
of an eNB (NP-ENB) other than the P-eNB; generating a first Radio
Link Control Packet Data Unit (RLC PDU) using the received packet;
and transmitting the first RLC PDU to the NP-ENB.
2. The method of claim 1, further comprising: receiving a MAC
Service Data Unit (SDU) from the NP-ENB; generating a second RLC
PDU corresponding to the MAC SDU; and transmitting the second RLC
PDU, which is converted, to the serving gateway through the NP-EPS
bearer.
3. A communication method of a non-primary evolved node B (NP-ENB)
other than a primary eNB (P-ENB) controlling a primary cell (PCell)
of a User Equipment (UE), the method comprising: receiving a Radio
Link Control Packet Data Unit (RLC PDU) from the P-ENB;
re-segmenting the RLC PDU into re-segmented RLC PDUs; and
transmitting the re-segmented RLC PDUs, which are converted to
signals, to the UE.
4. The method of claim 3, further comprising: receiving a signal
from the UE; generating a Media Access Control Service Data Unit
(MAC SDU) using the signal; and transmitting the MAC SDU to the
P-ENB.
5. A communication apparatus of a primary evolved node B (P-ENB)
controlling a primary cell (PCell) of user equipment (UE), the
apparatus comprising: a communication unit which receives a packet
from a serving gateway through a non-primary Evolved Packet System
(NP-EPS) bearer for serving cells of an eNB (NP-ENB) other than the
P-eNB; and a control unit which generates a first Radio Link
Control Packet Data Unit (RLC PDU) using the received packet,
wherein the communication unit transmits the first RLC PDU to the
NP-ENB.
6. The apparatus of claim 5, wherein the communication unit
receives a MAC Service Data Unit (SDU) from the NP-ENB, the control
unit generates a second RLC PDU corresponding to the MAC SDU, and
the communication unit transmits the second RLC PDU, which is
converted, to the serving gateway through the NP-EPS bearer.
7. A communication apparatus of a non-primary evolved node B
(NP-ENB) other than a primary eNB (P-ENB) controlling a primary
cell (PCell) of a User Equipment (UE), the apparatus comprising: a
communication unit which receives a Radio Link Control Packet Data
Unit (RLC PDU) from the P-ENB; and a control unit which re-segments
the RLC PDU into re-segmented RLC PDUs, the communication unit
transmits the re-segmented RLC PDUs, which are converted to
signals, to the UE.
8. The apparatus of claim 7, wherein the communication unit
receives a signal from the UE, the control unit generates a Media
Access Control Service Data Unit (MAC SDU) using the signal, and
the communication unit transmits the MAC SDU to the P-ENB.
Description
TECHNICAL FIELD
[0001] The present invention relates to a data multicarrier-based
data communication method and apparatus for use in a mobile
communication system.
BACKGROUND ART
[0002] Mobile communication systems were developed to provide
mobile users with communication services. With the rapid advance of
technologies, the mobile communication systems have evolved to the
level capable of providing high speed data communication service
beyond the early voice-oriented services.
[0003] Recently, standardization for a Long Term Evolution (LTE)
system, as one of the next-generation mobile communication systems,
is underway in the 3.sup.rd Generation Partnership Project (3GPP).
LTE is a technology for realizing high-speed packet-based
communications with the data rate of up to 100 Mbps, which is
higher than the currently available data rate, and its
standardization is almost complete.
[0004] In line with the completion of the LTE standardization, an
LTE-Advanced (LTE-A) system is now under discussion, which improves
a transfer rate by combining the LTE communication system with
several new technologies. One of such technologies is Carrier
Aggregation. The Carrier Aggregation is a technology allowing a
terminal to use multiple downlink carriers and multiple uplink
carriers unlike the conventional technology of using one downlink
carrier and one uplink carrier for data communication.
[0005] Currently, the LTE-A is featured with the intra-eNB carrier
aggregation only. This restricts applicability of the carrier
aggregation function so as to a problem of failing aggregation of
macro and pico cells in a scenario where a plurality of pico cells
and a macro cell operate in an overlapped manner.
DISCLOSURE OF INVENTION
Technical Problem
[0006] The present invention has been conceived to solve at least
part of the above problem and aims to provide an inter-eNB carrier
aggregation method and apparatus.
Solution to Problem
[0007] In accordance with an aspect of the present invention, a
communication method of an evolved Node B of controlling a primary
cell (P-ENB) of a User Equipment (UE) includes receiving a packet
from a serving gateway through a non-primary Evolved Packet System
(NP-EPS) bearer for serving cells of an eNB (NP-ENB) other than the
P-eNB, generating a first Radio Link Control Packet Data Unit (RLC
PDU) using the received packet, and transmitting the first RLC PDU
to the NP-ENB.
[0008] In accordance with another aspect of the present invention,
a communication method of a non-primary evolved node B (NP-ENB)
other than a primary eNB (P-ENB) controlling a primary cell (PCell)
of a User Equipment (UE) includes receiving a Radio Link Control
Packet Data Unit (RLC PDU) from the P-ENB, re-segmenting the RLC
PDU into re-segmented RLC PDUs, and transmitting the re-segmented
RLC PDUs, which are converted to signals, to the UE.
[0009] In accordance with another aspect of the present invention,
a communication apparatus of a primary evolved node B (P-ENB)
controlling a primary cell (PCell) of user equipment (UE) includes
a communication unit which receives a packet from a serving gateway
through a non-primary Evolved Packet System (NP-EPS) bearer for
serving cells of an eNB (NP-ENB) other than the P-eNB and a control
unit which generates a first Radio Link Control Packet Data Unit
(RLC PDU) using the received packet, wherein the communication unit
transmits the first RLC PDU to the NP-ENB.
[0010] In accordance with still another aspect of the present
invention, a communication apparatus of a non-primary evolved node
B (NP-ENB) other than a primary eNB (P-ENB) controlling a primary
cell (PCell) of a User Equipment (UE) includes a communication unit
which receives a Radio Link Control Packet Data Unit (RLC PDU) from
the P-ENB and a control unit which re-segments the RLC PDU into
re-segmented RLC PDUs, the communication unit transmits the
re-segmented RLC PDUs, which are converted to signals, to the
UE.
Advantageous Effects of Invention
[0011] The present invention is advantageous in terms of reducing
battery consumption of the UE by applying discontinuous reception
in the inter-eNB carrier aggregation mode.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a diagram illustrating the architecture of an LTE
system to which some embodiments of the present invention are
applied.
[0013] FIG. 2 is a diagram illustrating a protocol stack of the LTE
system to which some embodiments of the present invention are
applied.
[0014] FIG. 3 is a diagram illustrating the concept of typical
intra-eNB carrier aggregation.
[0015] FIG. 4 is a diagram illustrating the concept of inter-eNB
carrier aggregation according to an embodiment of the present
invention.
[0016] FIG. 5 is a signal flow diagram illustrating the operations
of the UE and the eNB for configuring a SCell belonging to the
primary set according to an embodiment of the present
invention.
[0017] FIG. 6 is a signal flow diagram illustrating the procedure
of configuring a SCell belonging to a non-primary set.
[0018] FIG. 7 is a diagram illustrating the structure of the RRC
control message according to an embodiment of the present
invention.
[0019] FIG. 8 is a diagram illustrating the structure of the RRC
control message according to another embodiment of the present
invention.
[0020] FIG. 9 is a mimetic diagram illustrating a split scheme
according to an embodiment of the present invention.
[0021] FIG. 10 is a diagram illustrating the first PDCP
distribution structure according to an embodiment of the present
invention.
[0022] FIG. 11 is a diagram illustrating the second PDCP
distribution structure according to an embodiment of the present
invention.
[0023] FIG. 12 is a diagram illustrating the first RLC distribution
structure according to an embodiment of the present invention.
[0024] FIG. 13 is a diagram illustrating the first MAC distribution
structure according to an embodiment of the present invention.
[0025] FIG. 14 is a diagram illustrating the second MAC
distribution structure according to an embodiment of the present
invention.
[0026] FIG. 15 is a diagram illustrating a structure of a data unit
according to an embodiment of the present invention.
[0027] FIG. 16 is a diagram illustrating the configuration of RLC
and MAC entities in the second MAC distribution structure according
to an embodiment of the present invention.
[0028] FIG. 17 is a diagram illustrating the second RLC
distribution structure according to an embodiment of the present
invention.
[0029] FIG. 18 is a signal flow diagram illustrating the operation
of adding primary set and non-primary sets serving cells and
configuring DRB according to an embodiment of the present
invention.
[0030] FIG. 19 is a signal flow diagram illustrating the procedure
of releasing SCell and transmitting/receiving data according to an
embodiment of the preset invention.
[0031] FIG. 20 is a signal flow diagram illustrating a procedure of
releasing the SCell and transmitting/receiving data according to
another embodiment of the present invention.
[0032] FIG. 21 is a diagram illustrating a ciphering/deciphering
procedure according to an embodiment of the present invention.
[0033] FIG. 22 is a diagram illustrating the radio link monitoring
procedure according to an embodiment of the present invention.
[0034] FIG. 23 is a flowchart illustrating an RLF detection
procedure according to an embodiment of the present invention.
[0035] FIG. 24 is a flowchart illustrating the LCP procedure
according to an embodiment of the present invention.
[0036] FIG. 25 is a signal flow diagram illustrating the PHR
trigger and transmission procedure according to an embodiment of
the present invention.
[0037] FIG. 26 is a diagram illustrating a PHR format according to
an embodiment of the present invention.
[0038] FIG. 27 is a signal flow diagram illustrating a procedure of
determining a subframe pattern according to an embodiment of the
present invention.
[0039] FIG. 28 is a diagram illustrating a timing difference
according to an embodiment of the present invention.
[0040] FIG. 29 is a block diagram illustrating a configuration of
the UE according to an embodiment of the present invention.
[0041] FIG. 30 is a block diagram illustrating a configuration of
the P-ENB according to an embodiment of the present invention.
[0042] FIG. 31 is a block diagram illustrating a configuration of
the NP-ENB according to an embodiment of the present invention.
[0043] FIG. 32 is a diagram illustrating a multi-PDCP structure
according to an embodiment of the present invention.
[0044] FIG. 33 is a diagram illustrating a multi-RLC structure
according to an embodiment of the present invention.
MODE FOR THE INVENTION
[0045] Detailed description of well-known functions and structures
incorporated herein may be omitted to avoid obscuring the subject
matter of the present invention. Exemplary embodiments of the
present invention are described with reference to the accompanying
drawings in detail. Prior to the description of the present
invention, the LTE system and the carrier aggregation are explained
briefly.
[0046] FIG. 1 is a diagram illustrating the architecture of an LTE
system to which some embodiments of the present invention are
applied.
[0047] Referring to FIG. 1, the radio access network of the mobile
communication system includes evolved Node Bs (eNBs) 105, 110, 115,
and 120, a Mobility Management Entity (MME) 125, and a
Serving-Gateway (S-GW) 130. The User Equipment (hereinafter,
referred to as UE) 135 connects to an external network via eNBs
105, 110, 115, and 120 and the S-GW 130.
[0048] In FIG. 1, the eNBs 105, 110, 115, and 120 correspond to the
legacy node Bs of the UMTS system. The eNBs allow the UE 135 to
establish a radio channel and are responsible for complicated
functions as compared to the legacy node B. In the LTE system, all
the user traffic including real time services such as Voice over IP
(VoIP) are provided through a shared channel and thus there is a
need of a device to schedule data based on the state information
such as buffer states, power headroom states, and channel states of
the UEs; and the eNBs 110, 115, and 120 are responsible for this.
Typically, one eNB controls a plurality of cells. In order to
secure the data rate of up to 100 Mbps, the LTE system adopts
Orthogonal Frequency Division Multiplexing (OFDM) as a radio access
technology. Also, the LTE system adopts Adaptive Modulation and
Coding (AMC) to determine the modulation scheme and channel coding
rate in adaptation to the channel condition of the UE. The S-GW 130
is an entity to provide data bearers so as to establish and release
data bearers under the control of the MME 125. The MME 125 is
responsible for mobility management of UEs and various control
functions and may be connected to a plurality of eNBs.
[0049] FIG. 2 is a diagram illustrating a protocol stack of the LTE
system to which some embodiments of the present invention are
applied.
[0050] Referring to FIG. 2, the protocol stack of the LTE system
includes Packet Data Convergence Protocol (PDCP) 205 and 240, Radio
Link Control (RLC) 210 and 235, Medium Access Control (MAC) 215 and
230, and Physical (PHY) 220 and 225. The PDCP 205 and 240 is
responsible for IP header compression/decompression, and the RLC
210 and 235 is responsible for segmenting the PDCP Protocol Data
Unit (PDU) into segments in appropriate size for Automatic Repeat
Request (ARQ) operation. The MAC 215 and 230 is responsible for
establishing connection to a plurality of RLC entities so as to
multiplex the RLC PDUs into MAC PDUs and demultiplex the MAC PDUs
into RLC PDUs. The PHY 220 and 225 performs channel coding on the
MAC PDU and modulates the MAC PDU into OFDM symbols to transmit
over radio channel or performs demodulating and channel-decoding on
the received OFDM symbols and delivers the decoded data to the
higher layer.
[0051] FIG. 3 is a diagram illustrating the concept of typical
intra-eNB carrier aggregation.
[0052] Referring to FIG. 3, an eNB transmits and receives signals
through multiple carriers across a plurality of frequency bands.
For example, the eNB 305 can be configured to use the carrier 315
with center frequency f1 and the carrier 310 with center frequency
f3. If carrier aggregation is not supported, the UE 330 has to
transmit/receive data using one of the carriers 310 and 315.
However, the UE 330 having the carrier aggregation capability can
transmit/receive data using both the carriers 310 and 315. The eNB
can increase the amount of the resource to be allocated to the UE
having the carrier aggregation capability in adaptation to the
channel condition of the UE so as to improve the data rate of the
UE 330. The technique of aggregating the downlink and uplink
carriers respectively for transmission and reception at one eNB is
referred to as intra-eNB carrier aggregation. In any case, however,
there may be a need of aggregating the downlink/uplink carriers of
different eNBs unlike the situation depicted in FIG. 3.
[0053] FIG. 4 is a diagram illustrating the concept of inter-eNB
carrier aggregation according to an embodiment of the present
invention.
[0054] Referring to FIG. 4, assuming that the eNB 1 405 uses the
carrier with center frequency f1 for transmission/reception and the
eNB 2 420 the carrier with center frequency f2 for
transmission/reception, if the downlink carrier with the center
frequency f1 and the downlink carrier with the center frequency f2
are aggregated, this means that the carriers transmitted by two or
more eNBs are aggregated for one UE and thus such a carrier
aggregation is referred to as inter-eNB Carrier Aggregation (CA) in
the present invention.
[0055] The terms to be used frequently in the present invention are
described hereinafter.
[0056] Assuming that a cell is configured with one downlink carrier
and one uplink carrier in the conventional concept, the carrier
aggregation can be understood as if the UE communicates data via
multiple cells. With the use of carrier aggregation, the peak data
rate increases in proportion to the number of aggregated
carriers.
[0057] In the following description, if a UE receives data through
a certain downlink carrier or transmits data through a certain
uplink carrier, this means to receive or transmit data through
control and data channels provided in cells corresponding to center
frequencies and frequency bands characterizing the carriers. In the
present Invention, carrier aggregation may be expressed as
configuring a plurality of serving cells with the use of terms such
as primary cell (PCell), secondary cell (SCell), and activated
serving cell. These terms are used as they are in the LTE mobile
communication system.
[0058] In the present invention, a group of the serving cells
controlled by an eNB is defined as set. The set is classified into
one of primary set and non-primary set. The primary set is a set of
serving cells controlled by the eNB controlling the PCell (primary
eNB), and the non-primary set is a set of serving cells controlled
by the eNB not controlling the PCell (non-primary eNB). The eNB
notifies the UE whether a serving cell belongs to the primary set
or non-primary set in the process of configuring the corresponding
serving cell. One UE can be configured with one primary set and one
or more non-primary sets.
[0059] In the following description, other terms may be used
interchangeable with the terms `primary set` and `non-primary set`
to help understanding. For example, the terms `primary set` and
`secondary set` or `primary carrier group` and `secondary carrier
group` may be used. However, it is noted that different terms are
used interchangeably but in the same meanings. The main purpose of
using these terms is to distinguish between the cells under control
of the eNB controlling the PCell of a specific UE and other cells,
and the UE and the corresponding cell operate distinctly depending
on whether the cell is controlled by the eNB controlling the PCell
of the specific UE.
[0060] FIG. 5 is a signal flow diagram illustrating the operations
of the UE and the eNB for configuring a SCell belonging to the
primary set according to an embodiment of the present
invention.
[0061] Referring to FIG. 5, the mobile communication system
includes a UE 505, eNB 1 515, and eNB 2 510. The cells 1, 2, and 3
are controlled by the eNB 1, and the cells 4 and 4 are control by
the eNB 2 510. Suppose that the PCell of the UE is the cell 1 and
the eNB 1. According to the definition of the primary eNB, the eNB
1 515 is the primary eNB. The eNB 1 515 as the primary eNB attempts
to configure cell 2 as an additional SCell to the UE. In the
present invention, the eNB controlling the PCell, i.e. controlling
the primary set, is referred to as a serving eNB. The eNB which is
not the serving eNB of the UE and controls the serving cell of the
UE is referred to as the drift eNB. The eNB controlling the serving
cells of the primary set is the serving eNB, and the eNB
controlling the serving cells of the non-primary set is the drift
eNB. The terms `primary eNB` and `non-primary eNB` may be used
substitutionally. The primary eNB corresponds to the serving eNB,
and the non-primary eNB corresponds to the drift eNB.
[0062] The serving eNB 515 sends the UE 505 a Radio Resource
Control (RRC) Connection Reconfiguration control message including
the information on the SCell to be added newly at step 520. The
SCell to be added newly is the cell managed by the serving eNB
directly. The control message may include some of the information
as listed in table 1 depending on the serving cell.
TABLE-US-00001 TABLE 1 Name Description sCellIndex-r10 Identifier
of serving cell. An integer having a predetermined size. Used in
updating information on the corresponding serving cell in the
future. cellIdentification-r10 Information for use in identifying
the serving cell physically. Composed of downlink center frequency
and Physical Cell ID (PCI). radioResourceConfig- Information on
radio resource of service cell. For example, this CommonSCell-r10
includes downlink bandwidth, downlink Hybrid ARQ (HARQ) feedback
channel configuration information, uplink center frequency
information, uplink bandwidth information, etc.
radioResourceConfig- Information on UE-specific resource allocated
in the serving DedicatedSCell-r10 cell. For example, this includes
channel quality measurement reference signal structure information,
inter-carrier scheduling configuration information, etc. TAG(Timing
Information indicating TAG to which UE belongs. For example,
Advance Group) this may include TAG id and Timing Advance (TA)
timer. If the information UE belongs to P-TAG, this information may
not be signaled.
[0063] The TAG is a set of the serving cells sharing the same
uplink transmission timing. A TAG is classified into one of Primary
TAG (P-TAG) and Secondary TAG (S-TAG): the P-TAG is of including
the PCell and the S-TAG is of including only SCells with the
exception of PCell. If a certain serving cell belongs to a certain
TAG, this means that the uplink transmission timing of the serving
cell is identical with those of the other serving cells belonging
to the TAG and whether the uplink synchronization is acquired is
determined by means of the TA timer of the TAG. The uplink
transmission timing of a certain TAG is set through a random access
process in a serving cell belonging to the TAG and maintained with
the receipt of TA command. The UE starts or restart the TA timer of
the corresponding TAG whenever the TA command for the corresponding
TAG is received. If the TA timer expires, the UE determines that
the uplink transmission synchronization of the corresponding TAG
has broken and thus suspends uplink transmission until the next
random access occurs.
[0064] The UE 505 transmits a response message (RRC Connection
Reconfiguration Complete) in response to the control message at
step 525. The UE 505 establishes DL/UL synchronization with the
cell 2, i.e. serving cell 1, at step 530. The forward/downlink is
of transmitting at the eNB and receiving at the UE, and
reverse/uplink is of transmitting at the UE and receiving at the
eNB. In the present invention, the terms `forward` and `downlink`
are used interchangeably. Also, the terms `reverse` and `uplink`
are used interchangeably. Establishing downlink synchronization
with a certain cell is acquiring the synchronization channel of the
cell to check the downlink frame boundary. The serving eNB 515
sends the UE an Activate/Deactivate MAC Control Element (A/D MAC
CE) as a MAC layer control command to instruct activating the SCell
1 at step 535. The control command is structured in the form of a
bitmap. The first bit may correspond to the SCell 1, the second bit
to SCell 2, and the n.sup.th bit to SCell n. Each bit indicates
activation/deactivation of the corresponding SCell. The bitmap may
be 1-byte long. Since 7 SCell indices, i.e. from 1 to 7, exist, the
second Least Significant Bit (LSB) is mapped to the SCell 1, the
third LSB to SCell 2, and the last LSB or the Most Significant Bit
(MSB) to SCell 7, without use of the first LSB.
[0065] The UE 505 starts monitoring Physical Downlink Control
Channel (PDCCH) of SCell 1 after a lapse from the time when the
activation command for the SCell 1 is received. The PDCCH is the
channel of carrying DL/UL transmission resource allocation
information. If the SCell 1 belongs to the TAG with which the
synchronization has been established already, the UE 505 starts
DL/UL communication from the monitoring start time. If the SCell 1
belongs to the TAG with which synchronization has not been
established, the UE 505 starts receiving downlink signal at the
monitoring start time but not transmitting uplink signals. That is,
if the downlink transmission resource allocation information is
received on the PDCCH, the UE receives downlink data but ignores
the uplink transmission resource information although it has been
received. If the SCell 1 belongs to a non-synchronized TAG, the UE
waits for the receipt of `random access command` on PDCCH in a
SCell belonging to the TAG. The random access command is a value of
a predetermined field of the uplink transmission resource
allocation information to instruct the UE to transmit a preamble in
a serving cell. The Carrier Indicator Field of the random access
command may carry the identifier of the serving cell for preamble
transmission.
[0066] The UE 505 receives a random access command instructing to
transmit the random access preamble in the serving cell 1 at step
540. The UE monitors PDCCH of the PCell to receive Random Access
Response (RAR) in reply to the preamble after transmitting the
preamble through the SCell 1 at step 545. The RAR may include TA
command and other control information. If the preamble is
transmitted by the serving eNB, it is likely to be efficient to
send the response in replay to the preamble through the PCell in
various aspects. For example, since the RAR is received only
through the PCell, it is possible to reduce the PDCCH monitoring
load of the UE 505. Accordingly, the UE monitors the PDCCH of the
PCell to receiving RAR at step 550. If a valid response message is
received in reply to the preamble, the UE 505 assumes that it is
possible to transmit uplink signal transmission after the elapse of
a predetermined period from that time point. For example, if the
valid RAR is received at the subframe n, it is determined that the
uplink transmission is possible from the subframe (n+m).
[0067] FIG. 6 is a signal flow diagram illustrating the procedure
of configuring a SCell belonging to a non-primary set.
[0068] The serving eNB 615 determines to add a SCell to the UE 605
at a certain time point. Particularly if the UE 605 is located in
the area of a cell controlled by the eNB 2 610, the serving eNB
determines to add the cell controlled by the eNB 2 as a SCell at
step 620. Next, the serving eNB 615 sends the eNB 2 610 a control
message requesting to add the SCell at step 625. The control
message includes at least part of the informations listed in table
2.
TABLE-US-00002 TABLE 2 Name Description SCell id info. Information
related to the identifiers of SCells to be configured by the drift
eNB. Formed with one or more sCellIndex-r10. Determined by the
serving cell and notified to the drift eNB to prevent the
identifier in use by the serving eNB from being reused. Or the
regions for SCell id used by the serving eNB and SCell id used by
the drift eNB may be defined separately. For example, the SCell ids
1 to SCell id 3 are reserved for use by the serving eNB and the
SCell id 4 to SCell id 7 for use by the drift eNB. TAG id info.
Information related to identifier of TAG to be configured by the
drift eNB. Defined by the serving eNB and notified to the drift eNB
to prevent the identifier in used by the serving eNB from being
reused. UL scheduling info. Include priority informations of
logical channels and logical channel group information configured
to the UE. The drift information interprets the UE buffer state
report information and performs uplink scheduling using this
information. Offload bearer info. It is preferred for the EDNB to
process the service requiring burst data transmission/reception,
e.g. FTP. The serving eNB determines the bearer to offload to the
drift eNB among the bearers configured to the UE and sends the
drift eNB the information on the bearer to be offloaded, e.g. DRB
identifier, PDCP configuration information, RLC configuration
information, and required QoS information. Call Admission The
serving eNB provides reference information in order for Control
info. the drift eNB to accept or reject the SCell Add Request,
e.g., required data rate, estimated UL data amount, and estimated
DL data amount.
[0069] If the SCell Add Request control message is received, the
drift eNB 610 determines whether to accept the request in
consideration of the current load status. If it is determined to
accept the request, the drift eNB 610 sends the serving eNB a
control message including at least part of the informations listed
in table 3 at step 630.
TABLE-US-00003 TABLE 3 Name Description SCellToAddMod This is the
information on the SCells configured by the drift eNB and includes
the information as follows. sCellIndex-r10, cellIdentification-r10,
radioResourceConfigCommonSCell-r10,
adioResourceConfigDedicatedSCell-r10, TAG information PUCCH At
least one of SCells belonging to the non-primary set is
configuration configured with Physical Uplink Control Channel
(PUCCH). information for Uplink control information such as HARQ
feedback, Channel PUCCH SCell Status Information (CSI), Sounding
Reference Signal (SRS), and Scheduling Request (SR) is transmitted.
Hereinafter, the SCell in which PUCCH is transmitted is referred to
as PUCCH SCell. The PUCCH SCell identifier and PUCCH configuration
information are the sub-informations of this information. Data
forwarding Information on Logical channel (or logical tunnel) for
use in info. data exchange between the serving eNB and drift eNB:
including GPRS Tunnel Protocol (GTP) tunnel identifier for downlink
data exchange and GTP tunnel identifier for uplink data exchange.
UE identifier C-RNTI to be used by UE in SCells of non-primary set.
Hereinafter, referred to as C-RNTI_NP Bearer Configuration
information on the bearer to be offloaded. This configuration info.
includes a list of bearers accepted to be offloaded. If the bearer
configurations are identical with each other, this information may
include only the list of the accepted bearers.
[0070] If the control message is received, the serving eNB 615
sends the UE 605 an RRC control message instructing to add the
serving cell at step 635. The RRC control message includes at least
part of the informations listed in table 4.
TABLE-US-00004 TABLE 4 Name Description SCellAddMod This includes
the information transmitted by the drift eNB without modification.
That is, this is identical with SCellAddMod in table 3. This
includes SCellAddMod per SCell and is sub- information of
SCellAddModList. PUCCH This includes the information transmitted by
the drift eNB configuration info. without modification. That is,
this is identical with PUCCH for PUCCH SCell information for PUCCH
SCell in table 3. Non-primary set This is the information on the
SCells belonging to the non- serving cell info. primary set among
the SCells to be configured. This may be the identifiers of the
SCells or the TAGs belonging to the non- primary set. UE identifier
C-RNTI to be used by UE in SCells of non-primary set, i.e. C- RNTI
+ NP. Offload bearer info. Information about barriers to be
processed by the drift eNB. This is the information about the
bearer for transmission/ reception through serving cells of the
non- primary set in view of the UE and includes the bearer list
and, if they are different from each other, the bearer
configuration informations.
[0071] The RRC control message may include the configuration
information of a plurality of SCells. The serving cells of the
primary and non-primary sets may be configured together. For
example, if the cells 2, 3, 4, and 5 are configured to the UE
having the cell 1 as its PCell, the informations thereon may be
arranged in the RRC control message in various orders.
[0072] FIG. 7 is a diagram illustrating the structure of the RRC
control message according to an embodiment of the present
invention. In this embodiment, the Cell 1 and Cell 2 have the same
uplink transmission timing to form the P-TAG, the Cell 3 forms the
S-TAG 1, and the Cell 4 and Cell 5 form the S-TAG 2.
[0073] The RRC control message contains SCellToAddModList 705
including SCellToAddMod 710 for Cell 2, SCellToAddMod 715 for Cell
3, SCellToAddMod 720 for Cell 4, and SCellToAddMod 725 for Cell
5.
[0074] The SCellToAddMod 710, 715, 720, and 725 may include
specific information or not depending on the characteristic of the
corresponding SCell. If the SCell belongs to the P-TAG, i.e. if the
SCell has the same uplink transmission timing as the PCell, the
corresponding SCellToAddMod does not include the information
related to the TAG. For example, the SCellToAddMod 710 for the Cell
2 does not include the information about TAG. The SCellToAddMod
715, 720, and 725 for the SCells of the rest non-P-TAGs may include
the TAG identifiers and TA timer values of the TAGs to which the
corresponding SCells belong.
[0075] The information on at least one of the cells belonging to
the non-primary set may include the non-primary set information
730, e.g. non-primary set identifier and C-RNTI for use by the UE
in the non-primary set. In the example of FIG. 7, the SCellToAddMod
715 for the cell 4 includes the non-primary set information 730.
The information on one of the cells belonging to the non-primary
set includes PUCCH configuration information 735. In the example of
FIG. 7, the SCellToAddMod 715 for the cell 4 includes this
information. To the SCell which belongs to the non-primary set but
has no non-primary set information, the non-primary set information
of the SCell having the same TAG id is applied. For example,
although the information on the cell 5 includes no non-primary set
information, the UE can check that the cell 5 belongs to the
non-primary set based on the non-primary set information of the
cell 4 which has the same TAG id and use the non-primary set
identifier and C-RNTI of the cell 4 for identifying the cell 5.
[0076] FIG. 8 is a diagram illustrating the structure of the RRC
control message according to another embodiment of the present
invention.
[0077] FIG. 8 shows another example of arranging the TAG-related
information and the non-primary set-related information in separate
regions other than SCellToAddMod.
[0078] The RRC control message includes SCellToAddModList 805
containing SCellToAddMod 810 for cell 2, SCellToAddMod for cell 3,
SCellToAddMod for cell 4, and SCellToAddMod for cell 5. The
SCellToAddMod may include the same type of informations. That is,
every SCellToAddMod includes the information such as
sCellIndex-r10, cellIdentification-r10, and
radioResourceConfigCommonSCell-r10.
[0079] The TAG information 815, the non-primary set information
820, and the PUCCH configuration information of PUCCH SCell 825 may
be included separately. The TAG information 815 includes the TAG
identifiers, identifiers of the SCells forming the TAG, and TA
timer value. For example, the TAG information 815 includes the
information 830 indicating that the TAG having the TAG identifier 1
includes the SCell 2 and that the TA timer is set to the value t1
and the information 835 indicating that the TAG having the TAG
identifier 2 includes the SCell 3 and SCell 4 and that the TA timer
is set to the value t2.
[0080] The non-primary set information 820 includes the
per-non-primary set identifiers, identifiers of the serving cells
included in the set, and C-RNTI for use in the corresponding set.
For example, the information 840 indicating that the non-primary
set having the set identifier 1 includes the SCell 3 and SCell 4
and uses the C-RNTI x. The primary set information is determined
according to the following rule without explicit signaling.
[0081] <Primary Set Information Determination Rule>
[0082] Serving cell belonging to primary set: PCell and SCells not
belonging to any non-primary set
[0083] C-RNTI to be used in primary set: C-RNTI in use currently in
PCell
[0084] The non-primary set information may include the TAG
identifier other than the SCell identifier. This is possible under
the assumption that the set and TAG are formed such that one TAG is
not formed across multiple sets. For example, the non-primary set
configuration information 820 may include the information
indicating the TAG id 2 instead of the information indicating the
SCell 3 and SCell 4 in order for the UE to determine that the SCell
3 and SCell 4 having the TAG id 2 belong to the non-primary
set.
[0085] The PUCCH SCell's PUCCH configuration information is made up
of non-primary set identifier, PUCCH SCell identifier, and PUCCH
configuration information. Each non-primary set has one PUCCH
SCell, and the CSI information for the serving cells belonging to
the non-primary set and HARQ feedback information may be
transmitted on the PUCCH configured to the PUCCH SCell.
[0086] The PUCCH SCell can be determined according to a
predetermined rule without signaling PUCCH SCell identifier
explicitly. For example, the SCell corresponding to the first
SCellToAddMod of the SCellToAddModList may be assumed as the PUCCH
SCell. Also, the SCell having the highest or lowest SCell
identifier among the SCells of which information includes the
SCellToAddMod information in the corresponding RRC control message
may be determined as the PUCCH SCell. Such an implicit
determination method can be used under the assumption that only one
non-primary set exists.
[0087] Returning to FIG. 6, the UE 605 sends the serving eNB 615 a
response message at step 640 and establishes downlink
synchronization with the newly configured SCells at step 645. The
UE 605 acquires System Frame Number (SFN) of the PUCCH SCell among
the newly configured SCells at step 650. The SFN is acquired in the
process of receiving the system information, i.e. Master
Information Block (MIB). The SFN is an integer incrementing by 1
every 10 ms in the range of 0 to 1023. The UE 605 checks the PUCCH
transmission timing of the PUCCH SCell based on the SFN and PUCCH
configuration information.
[0088] Afterward, the UE 605 waits until the SCells are activated.
If downlink data or a predetermined control message instructing to
activate SCell is received from the serving eNB 615 at step 655,
the drift eNB 610 starts a procedure of activating the SCells.
[0089] The drift eNB 610 sends the UE 605 the A/D MAC CE
instructing to activate the SCell, e.g. SCell 3, at step 660. If
the MAC CE is received at the subframe n, the UE 605 activates the
SCell at subframe (n+m1). However, since the uplink synchronization
of the PUCCH SCell is not acquired yet at the subframe (n+m1), both
the downlink and uplink transmission/reception are not possible
although the SCell has been activated. That is, the UE 605 monitors
PDCCH of the SCell but ignores the downlink/uplink resource
allocation signal although it is received. The drift eNB 610 sends
the UE 605 a random access command to establish uplink
synchronization with the PUCCH SCell at step 665. The UE 605
initiates random access procedure in the PUCCH SCell using a
dedicated preamble indicated in the random access command. That is,
the UE 605 sends a preamble through the SCell at step 670 and
monitors PDCCH to receive RAR in response thereto. If the UE 605
transmits the preamble in the primary set, the RAR is transmitted
through the PCell. Otherwise if the preamble is transmitted in the
non-primary set, the UE 605 monitors PDCCH of the SCell in which
the preamble has been transmitted or the PUCCH SCell to receive
RAR. This is because there is a need of extra information exchange
between the drift eNB 610 and the serving eNB 615 to process the
RAR in the PCell. The RAR may be received with the C-RNTI_NP to be
used by the UE 605 in the non-primary set. It is more efficient to
transmit the response message with the C-RNTI.sub.--NP because the
UE 605 also has been allocated the C-RNTI_NP and there is no
probability of malfunctioning caused by collision due to the use of
the dedicated preamble (if the dedicated preamble is received, this
means that the eNB knows the UE 605 to which the RAR has to be
transmitted). If the valid response message is received through the
SCell in which the preamble has been transmitted or the PUCCH
SCell, the UE 605 adjusts the uplink transmission timing of the
PUCCH SCell and the TAG to which the PUCCH SCell based on the TA
command of the response message and activates uplink at a
predetermined time point. If the valid TA command or the valid
random access response message is received at the subframe n, the
predetermined timing becomes the subframe (n+m2). Here, m2 is a
predetermined integer.
[0090] Typically one user service is served on one Evolved Packet
System (EPS) bearer, and one EPS bearer is linked to one Radio
Bearer. The radio bearer is made up of PDCP and RLC and, in the
inter-eNB CA, it is possible to improve the data transmission
efficiency by placing the PDCP and RLC entities of one radio bearer
at different eNBs. In the following, the description is made under
the assumption that the serving eNB controls a macro cell and the
drift eNB a pico cell. The term `pico cell` is used in the similar
meaning of non-primary set serving cell and the term `macro cell`
in the similar meaning of primary set serving cell.
[0091] It is possible to consider two schemes: One in which an S-GW
discriminates between the EPS bearer to be processed by a macro
cell (P-EPS bearer) and the EPS bearer to be processed by a pico
cell (NP-EPS bearer) and the other in which all the EPS bearer
traffic is transferred to the primary eNB first and then the
primary eNB sends the drift eNB the data of the NP-EPS bearer. In
the following description, the former is referred to as Core
Network (CN) split and the latter is referred to as Radio Access
Network (RAN) split for explanation convenience.
[0092] FIG. 9 is a mimetic diagram illustrating a split scheme
according to an embodiment of the present invention.
[0093] In the case that the UE 920 is located in the area of the
macro cell but out of the range of the electric wave of the pico
cell as denoted by reference number 925, the UE 920 communicates
both the control plane data and user plane data with the eNB
controlling the macro cell (i.e. serving eNB) 910. The user plane
data 925 is processed by the S-GW 905, and the bearers for
transmitting/receiving the user plane data, i.e. EPS bearers 1 and
2, are all established between the S-GW 905 and the serving eNB
910. In the following description, it is assumed that the EPS
bearers 1 and 2 are NP-EPS bearer and P-EPS bearer respectively for
explanation convenience.
[0094] At a certain time, the UE 920 moves to a position to which
the electric waves of the pico and macro cells reach. In the case
of using the CN split scheme, the EPS bearer 1 is reconfigured
between the S-GW 905 and the drift eNB 915 as denoted by reference
number 930. The EPS bearer 2 is maintained between the S-GW and the
serving eNB. The serving eNB 910 communicates the EPS bearer 2 data
with the UE 905, and the drift eNB 915 communicate the EPS bearer 1
data with the UE 905. In the case of using the RAN split scheme,
both the EPS bearers 1 and 2 are maintained between the S-GW 905
and the serving eNB 910. The serving eNB 910 communicates the EPS
bearer 2 data with the UE 905 and forwards the EPS bearer 1 data to
the EPS bearer eNB 915. The drift eNB 915 communicates the EPS
bearer 1 data with the UE 920.
[0095] For explanation convenience in the following description,
the paths of the data transmitted/received through the primary set
serving cell are referred to as primary set EPS bearer (P-EPS
bearer), primary set DRB (P-DRB), and primary set logical channel
(P-LCH); and the paths of data transmitted/received through a
non-primary set serving cell are referred to as non-primary set EPS
bearer (NP-EPS bearer), non-primary set DRB (NP-DRB), and
non-primary set logical channel (NP-LCH).
[0096] FIG. 10 is a diagram illustrating the first PDCP
distribution structure according to an embodiment of the present
invention.
[0097] In the case of using the CN split, the P-EPS bearer 1005,
P-DRB, and P-LCH are configured to the primary eNB 1010; the NP-EPS
bearer 1015, NP-DRB, and NP-LCH are configured at the non-primary
eNB 1020. The UE communicates the P-EPS bearer data with the
primary set serving cell and communicates the NP-EPS bearer data
with the non-primary set serving cell.
[0098] In the case of using the RAN split, the P-DRB is configured
to the primary eNB, but the NP-DRB or NP-LCH may be configured to
the primary or non-primary eNB selectively.
[0099] The present invention proposes a first PDCP distribution
structure, a second PDCP distribution structure, a first MAC
distribution structure, a second MAC distribution structure, and a
second RLC distribution structure. Particularly, each structure is
described in association with the operation of the network and UE
and signaling mechanism in the configuration procedure.
[0100] The first PDCP distribution structure is characterized in
that the NP-EPS bearer is established between the S-GW and the
non-primary eNB 1010 and the NP-DRB and NP-LCH are configured to
the non-primary eNB 1010 in the case of applying the CN split as
described with reference to FIG. 10.
[0101] FIG. 11 is a diagram illustrating the second PDCP
distribution structure according to an embodiment of the present
invention.
[0102] The second PDCP distribution structure is characterized in
that the NP-EPS bearer 1115 is established between the S-GW and the
primary eNB 1110 and the NP-DRB 1125 is configured at the
non-primary eNB 1120. In the second PDCP distribution structure, a
GPRS Tunnel Protocol (GTP) tunnel is established between the
primary eNB 1110 and the non-primary eNB 1120 for data forwarding
such that the IP packet of the NP-EPS bearer 1115 is forwarded from
the P-ENB 1110 to the NP-ENB 1120 through the GTP tunnel or vice
versa. The second PDCP distribution structure has the
characteristics as follows. [0103] The PDCP status report control
message (PDCP STATUS REPORT; control message for reporting PDCP PDU
transmission/reception status) is forwarded from NP-ENB to P-ENB
through GTP tunnel. [0104] The RLC PDU size of the NP-DRB is
determined by a MAC scheduler of the
[0105] NP-ENB. Since both the RLC and MAC entities of the NP-DRB
are located in the NP-ENB, the RLC PDU size may be determined
dynamically by reflecting the channel condition of the current
time. [0106] The NP-EPS bearer data is transmitted/received through
only the non-primary set serving cells. The UE transmits the NP-EPS
bearer data using only the transmission resource allocated in the
non-primary set serving cell.
[0107] FIG. 12 is a diagram illustrating the first RLC distribution
structure according to an embodiment of the present invention.
[0108] The first RLC distribution structure is characterized in
that the NP-EPS bearer 1215 is established between the S-GW and the
P-ENB and a part of the NP-DRB, i.e. PDCP entity 1230 is configured
at the P-ENB and the RLC entity 1225 is configured at the NP-ENB
1220. In the first RLC distribution structure, the GPRS Tunnel
Protocol (GTP) tunnel is established between the primary eNB and
the non-primary eNB for data forwarding such that the PDCP PDU (or
RLC SDU) of the NP-EPS bearer is forwarded from the P-ENB to the
NP-ENB through the GTP tunnel or vice versa. The first RLC
distribution structure has the same characteristics as the second
PDCP distribution structure.
[0109] FIG. 13 is a diagram illustrating the first MAC distribution
structure according to an embodiment of the present invention.
[0110] The first MAC distribution structure is characterized in
that the NP-EPS bearer 1315 is established between the S-GW and the
P-ENB and the NP-DRB 1330 is configured at the P-ENB. In the first
MAC distribution structure, only the MAC and PHY layers entities
are configured at the N-eNB. In the first MAC distribution
structure, the GPRS Tunnel Protocol (GTP) tunnel is established
between the primary eNB and the non-primary eNB for data forwarding
such that the RLC PDU (or MAC SDU) of the NP-EPS bearer is
forwarded from the P-ENB to the NP-ENB through the GTP tunnel or
vice versa. The first MAC distribution structure has the
characteristics as follows. [0111] The RLC status report control
message (RLC STATUS PDU; control information reporting RLC PDU
transmission/reception status, i.e. containing RLC ACK/NACK
information) is forward from the NP-ENB to the P-ENB through the
GTP tunnel. [0112] The MAC scheduler of the NP-ENB notifies the RLC
entity of the P-ENB of the RLC PDU size. The RLC PDU size is
determined by reflecting the long term channel status of the
non-primary set serving cell and updated periodically. [0113] The
NP-EPS bearer data are transmitted/received through both the
primary and non-primary sets serving cells. The UE transmits the
NP-EPS bearer data using the transmission resource allocated in
both the primary and non-primary sets serving cells.
[0114] FIG. 14 is a diagram illustrating the second MAC
distribution structure according to an embodiment of the present
invention.
[0115] The second MAC distribution structure is characterized in
that the NP-EPS bearer 1415 is established between the S-GW and the
P-ENB. The NP-DRB 1430 is configured at the P-ENB 1410. The entity
1435 which is responsible for a partial function of the RLC entity
(hereinafter, referred to as low RLC entity) is configured at the
NP-ENB 1420. In the second MAC distribution structure too, the GPRS
Tunnel Protocol (GTP) tunnel is established between the primary eNB
1410 and the non-primary eNB 1420 for data forwarding such that the
RLC PDU (or MAC SDU) of the NP-EPS bearer 1415 is forwarded from
the P-ENB 1410 to the NP-ENB 1420 through the GTP tunnel or vice
versa. The low RLC entity 1435 of the NP-ENB 1420 re-segments the
RLC PDU from the P-ENB to a size in adaptation to the current
channel condition.
[0116] FIG. 15 is a diagram illustrating a structure of a data unit
according to an embodiment of the present invention.
[0117] The RLC PDU segmentation process aforementioned in
association with FIG. 14 is described in more detail with reference
to FIG. 15. The low RLC entity 1435 of the P-ENB 1410 sends the
NP-ENB 1420 the RLC PDU 1505 having a pre-negotiated size (e.g.
having the payload of 1500 bytes). The low RLC entity 1435 of the
NP-ENB 1420 stores the received RLC PDU 1505 in a buffer. The
scheduler of the NP-ENB 1420 determines to transmit the data at
certain timing and select a size of the data to be transmitted. The
data size is determined based on the channel condition and
scheduling status at the corresponding time point. The low RLC
entity 1435 re-segments the RLC PDU 1505 in adaptation to the
determined size and transfers the re-segmented RLC PDUs 1510 and
1520 to the MAC layer entity. The re-segmented RLC PDUs 1510 and
1520 may include segment headers 1515 and 1520 having an offset and
a last segment indicator. Here, the offset is the information
indicating what byte of the original RLC PDU corresponds to the
0.sup.th byte of the re-segmented RLC PDU payload, and the last
segment indicator is the information indicating whether the
re-segmented RLC PDU is the last segment. For example, since the
0.sup.th byte of the payload of the first re-segmented RLC PDU 1510
corresponds to the 0.sup.th byte of the original RLC PDU 1505, the
offset included in the segment header 1515 of the first
re-segmented RLC PDU 1510 may be set to 0. Also, since the first
re-segmented RLC PDU 1510 is not the last segment, the last segment
indicator of the segment header 1515 may be set to `NO.` Since the
0.sup.th byte of the payload of the second re-segmented RLC PDU
1520 is the 500.sup.th byte of the payload of the original RLC PDU
1505, the offset of the segment header 1525 of the second
re-segmented RLC PDU 1520 may be set to 500. Since the second
re-segmented RLC PDU 1520 is the last segment, the last segment
indicator of the segment header 1525 is set to `YES.` As described
above, the low RLC entity 1435 may re-segment the RLC PDU while
inserting the segment header as described above. Afterward, these
segments are transferred to another entity or component of
assembling the segments so as to be assembled based on the segment
headers 1515 and 1525.
[0118] The low RLC entity 1435 processes only the downlink data.
The uplink data is delivered from the MAC layer of the NP-ENB 1420
to the RLC entity of the P-ENB 1410 directly bypassing the low RLC
entity 1435.
[0119] In the second MAC distribution structure, the data of the
NP-EPS bearer 1415 are transmitted/received through all the serving
cells, i.e. primary and non-primary sets serving cells. The RLC PDU
size of the downlink data communicated through the primary set
serving cell is determined dynamically in consideration of the
channel condition and scheduling status of the corresponding
serving cell, and the RLC PDU size of the downlink data
communicated through the non-primary set serving cell is determined
by reflecting the long term channel status of the non-primary set
serving cell. Once determined, the size value is not changed for
relatively long duration. Hereinafter, the RLC PDU size determined
dynamically is referred to as dynamic RLC PDU size, and the RLC PDU
size reflecting the long term channel status so as to be applied
for relatively long time is referred to as static RLC PDU size. For
uplink data transmission, the dynamic PDU size is applied in both
the primary and non-primary sets serving cells.
[0120] FIG. 16 is a diagram illustrating the configuration of RLC
and MAC entities in the second MAC distribution structure according
to an embodiment of the present invention.
[0121] The RLC entity of the P-ENB has both the RLC reception
function 1605 and RLC transmission function 1610. The RLC
transmission function includes the RLC re-segmentation function
1615. The RLC re-segmentation function is of adjusting the size of
the RLC PDU in RLC retransmission, and the size of the RLC PDU
which is transmitted first is set to the dynamic RLC PDU size 1620
determined according to the channel condition/scheduling status at
the RLC PDU transmission timing.
[0122] The MAC entity 1650 of the P-ENB determines the dynamic RLC
PDU size 1620 before transmitting the RLC PDU and notifies the RLC
transmission function of the dynamic RLC PDU size. The MAC entity
1645 of the NP-ENB determines the static RLC PDU size in the SCell
configuration stet or flow control step and notifies the RLC
transmission function of the static RLC PDU size. The RLC
transmission function sets the size of the RLC PDU to be
transmitted through the primary set serving cell in adaptation to
the dynamic RLC PDU size 1620 and the size of the RLC PDU to be
transmitted through the non-primary set serving cell in adaptation
to the static RLC PDU size 1630.
[0123] The RLC transmission function 1610 determines the RLC SDU to
be transmitted through the primary set serving cell and the RLC SDU
to be transmitted through the non-primary set serving cell by
applying a predetermined scheme. For example, the RLC PDUs may be
sorted according to the ratio of reflections of the primary set
serving cell load status and the non-primary set serving cell load
status. Also, the ratio of the RLC SDUs to be transmitted through
the non-primary set serving cell to the total RLC SDUs may be
determined based on the data occurrence amount of the NP-EPS bearer
and estimated data rate of the non-primary set. The estimated data
rate of the non-primary set is the information which the scheduler
of the non-primary set determines in consideration of the load
status of the cells, channel condition of the UE, priority/weight
of the NP-EPS bearer, data occurrence amount of the NP-EPS bearer
and notifies to the primary eNB. The RLC transmission function
processes the RLC SDUs to be transmitted through the primary set
serving cell into the RLC PDUs fit to the dynamic RLC PDU size and
transmits them through the primary set serving cell, and processes
the RLC SDUs to be transmitted through the non-primary set serving
cell into the RLC PDUs fit to the static RLC PDU size and transmits
them through the non-primary eNB. The RLC transmission function may
transfer the retransmission RLC PDUs to the non-primary eNB in any
case. In this case, the transferred RLC PDUs are marked to indicate
that they are the retransmission RLC PDUs such that the non-primary
eNB transmits the retransmission RLC PDUs with priority. The
retransmission RLC PDU may be indicated with one of reserved bits
of the GTP header and implicitly by setting the size of the
retransmission RLC PDU which differs from that of the static RLC
PDU. The non-primary eNB transmits the retransmission RLC PDUs with
priority.
[0124] The second MAC distribution structure is characterized as
follows. [0125] The RLC status report control message (RLC STATUS
PDU; control message including transmission/reception status of RLC
PDU, i.e. RLC ACK/NACK information) is transmitted from the NP-ENB
to the P-ENB through the GTP tunnel. [0126] The MAC scheduler of
the NP-ENB instructs the RLC entity of the P-ENB to use the static
RLC PDU size, and the MAC scheduler of the P-ENB instructs the RLC
entity of the P-ENB to use the dynamic RLC PDU. The static RLC PDU
size is determined by reflecting the long term channel status of
the non-primary set serving cell and may be updated periodically.
[0127] The NP-EPS bearer data are communicated through both the
primary and non-primary sets serving cells. The UE transmits the
np-eps bearer data using the transmission resources allocated in
both the primary and non-primary sets serving cells. [0128] The
downlink data of the NP-EPS bearer is re-segmented into appropriate
size pieces by the low RLC entity of the NP-ENB and then
transmitted to the UE.
[0129] FIG. 17 is a diagram illustrating the second RLC
distribution structure according to an embodiment of the present
invention.
[0130] In the second RLC distribution structure, the NP-EPS bearer
1715 is established between the SGW and the P-ENB and part of the
NP-DRB, i.e. PDCP entity 1730 and RLC Rx entity 1733, is configured
at the NP-ENB 1720. The RLC Rx entity and RLC Tx entity are
separated for the following reason. In order to determine the RLC
PDU size for downlink data of the NP-EPS bearer by reflecting the
channel condition and scheduling status of the non-primary set
serving cell, the RLC transmission entity is located at the NP-ENB.
In order for the UE to use both the primary and non-primary sets
serving cells to transmit uplink data of the NP-EPS, the RLC Rx
entity is located at the P-ENB. If the RLC Rx entity is configured
at the NP-ENB and if the UE transmits RLC PDUs to the primary set
serving cell, the RLC PDUs has to be transferred from the P-ENB to
the NP-ENB and then transferred back after a necessary measure has
to be taken for the RLC Rx, and this problem can be avoided by
placing the RLC Rx entity at the P-ENB.
[0131] In the second RLC distribution structure, a GTP tunnel is
established between the primary and non-primary eNBs through which
the DL PDCP PDU (or RLC SDU) of the NP-EPS bearer is forwarded from
the P-ENB to the NP-ENB and the UL RLC PDU (or MAC SDU) is
transferred from the NP-ENB to the P-ENB. [0132] The RLC status
report control message (RLC STATUS PDU; control message reporting
RLC PDU transmission/reception status, i.e. including RLC ACK/NACK
information) is transferred from the NP-ENB to the P-ENB through
the GTP tunnel. [0133] The NP-EPS bearer DL data is transmitted
through the non-primary set serving cell. The NP-EPS bearer UL data
are transmitted through the primary and non-primary sets serving
cells.
[0134] FIG. 32 is a diagram illustrating a multi-PDCP structure
according to an embodiment of the present invention. In the
multi-PDCP structure, multiple DRBs are configured to the NP-EPS
bearers 3205 and 3220. It is possible to increase the peak data
rate of the EPS bearer using the multi-PDCP structure. FIG. 32 is
directed to the Tx entity and Rx entity. Each of the UE and the eNB
is provided with both the transmission device and the reception
device. In downlink, the distribution entity 3210 is configured at
the P-ENB, and the order rearrangement entity 3215 is configured at
the UE. In uplink, the distribution entity 3210 is configured at
the UE, and the order rearrangement entity 3215 is configured at
the P-ENB. In downlink, one of two DRBs is configured at the P-ENB,
and the other is configured at the NP-ENB 3230. In uplink too, one
DRB is configured at the P-ENB and the other at the NP-ENB.
[0135] The distribution entity 3210 distributes the NP-EPS bearer
traffic to the NP-DRBs linked to the NP-EPS bearer. Since the
distribution entity has no buffer, it distributes, if the NP-ENB
bearer traffic arrives, the traffic to one of the two DRBs. The
distribution entity of the P-ENB distributes the traffic in
consideration of the channel conditions and scheduling statuses of
the primary and non-primary sets serving cells. In more detail, the
distribution entity receives the estimated throughput information
from the MAC schedulers of the P-ENB and NP-ENB. It distributes the
traffic according to the ratio between the estimated throughputs of
the P-ENB and NP-ENB.
[0136] The distribution entity of the UE distributes the traffic
according to the instruction from the eNB. The eNB sends the UE a
non-primary set configuration control message, e.g. RRC Connection
Reconfiguration message 1855 including the distribution
information. The distribution information is the information
related to the ratio between the data amount to be transmitted
through the primary set serving cell (or data amount to be
transmitted on the P-DRB) and the data amount to be transmitted
through the non-primary set serving cell (or data amount to be
transmitted on the NP-DRB). This information may be the information
of indicating the ratio of the data to be transmitted through the
non-primary set serving cell, and the ratio of the data to be
transmitted through the primary set serving cell may be analogized
out of the this information. For example, if the distribution
information is 90, this means that the 90% of the data occurring on
the NP-EPS bearer during a predetermined period has to be
transmitted over the DRB of the non-primary set serving cell. As a
consequence, the ratio of the data to be transmitted over the DRB
of the primary set serving cell is 10%.
[0137] The order rearrangement operation is of determining whether
there is any missing NP-EPS bearer packet and, if so, waiting until
the missing NP-EPS bearer packet is received during a predetermined
period. The packet occurring later than the missing packet is
retained in the order rearrangement buffer until the missing packet
is acquired. In order to perform the order rearrangement operation,
there is a need of sequence number. In the present invention, the
order rearrangement operation is performed with the TCP sequence
number.
[0138] In the multi-PDCP structure too, a GTP tunnel for data
forwarding is established between the primary and non-primary eNBs
through which the DL PDCP SDU of the NP-EPS bearer is forward from
the P-ENB to the NP-ENB and the UL PDCP SDU from the NP-ENB to the
P-ENB.
[0139] FIG. 33 is a diagram illustrating a multi-RLC structure
according to an embodiment of the present invention. In the
multi-RLC structure, multiple RLC entities are configured to the
NP-EPS bearers 3305 and 5520. Using the multi-RLC structure, it is
possible to increase the peak data rate of the EPS bearer. FIG. 33
is directed to the Tx entity and Rx entity. Each of the UE and the
eNB is provided with both the transmission device and the reception
device. In downlink, the distribution entity 3310 is configured at
the P-ENB, and the order rearrangement entity 3315 is configured at
the UE. In uplink, the distribution entity 3310 is configured at
the UE, and the order rearrangement entity 3315 is configured at
the P-ENB. In downlink, one of two DRBs is configured at the P-ENB,
and the other is configured at the NP-ENB. In uplink too, one DRB
is configured at the P-ENB and the other at the NP-ENB. The
distribution entity is configured between the PDCP entity and the
RLC entity. In more detail, the distribution entity is configured
below the PDCP entity, particularly an entity of adding the PDCP
header. Also, the distribution entity is configured as a part of
the PDCP entity or the last processing entity of the PDCP
entity.
[0140] The distribution entity 3310 is responsible for distributing
the PDCP PDU to the RLC entities connected to the PDCP entity.
Since the distribution entity has no buffer, it distributes, if any
PDCP PDU is generated, to one the two RLC entities in real time.
The distribution entity of the P-ENB distributes the traffic in
consideration of the channel conditions and scheduling statuses of
the primary and non-primary sets serving cells. In more detail, the
distribution entity receives the estimated throughput information
from the MAC schedulers of the P-ENB and NP-ENB periodically. The
distribution entity distributes the traffic according to the ratio
between the estimated throughputs of the p-eNB and NP-ENB.
[0141] The distribution entity of the UE distributes the traffic
according to the instruction from the eNB. The eNB sends the UE a
non-primary set configuration control message, e.g. RRC Connection
Reconfiguration message 1855 including the distribution
information. The distribution information is the information
related to the ratio between the data amount to be transmitted
through the primary set serving cell (or data amount to be
transmitted on the P-DRB) and the data amount to be transmitted
through the non-primary set serving cell (or data amount to be
transmitted on the NP-DRB). This information may be the information
of indicating the ratio of the data to be transmitted through the
non-primary set serving cell, and the ratio of the data to be
transmitted through the primary set serving cell may be analogized
out of the this information. For example, if the distribution
information is 90, this means that the 90% of the data occurring on
the NP-EPS bearer during a predetermined period has to be
transmitted over the DRB of the non-primary set serving cell. As a
consequence, the ratio of the data to be transmitted over the DRB
of the primary set serving cell is 10%.
[0142] The order rearrangement operation is of determining whether
there is any missing NP-EPS bearer packet and, if so, waiting until
the missing NP-EPS bearer packet is received during a predetermined
period. The packet occurring later than the missing packet is
retained in the order rearrangement buffer until the missing packet
is acquired. In order to perform the order rearrangement operation,
there is a need of sequence number. In the present invention, the
order rearrangement operation is performed with the TCP sequence
number. The missing packet waiting time period is set by the eNB
and then notified to the UE.
[0143] The order rearrangement entity is configured between the RLC
entity and the PDCP entity. It is also possible to configure the
order rearrangement entity as a part of the PDCP entity. At this
time, the order rearrangement entity may be configured as the first
processing entity of the PDCP Rx entity. The PDCP entity performs
two types of order arrangement operations. The first order
rearrangement operation is executed only when a lower layer entity
such as handover is established, and the second order rearrangement
operation is running constantly. The first order rearrangement
operation is applicable to only the AM bearer, and the second order
rearrangement operation is applicable to both the RLC AM and UM
bearers. The eNB configures a bearer in such a way of determining
whether to apply the first order rearrangement operation, the
second order rearrangement operation, or both the order
rearrangement operations to the bearer, and notifies the UE of the
determination result using predetermined control information.
Whether to apply the first order rearrangement operation is
determined in association with whether to generate a PDCP status
report. The UE applies the first order rearrangement only to the
DRB configured to generate the PDCP status report. The first order
rearrangement operation is performed in such a way of storing the
PDCP packets required to be arranged in order among the PDCP
packets received after the reconfiguration of the low layer entity
and determining the packets to be delivered to the upper layer
among the stored PDCP packets by referencing the sequence numbers
of the received PDCP packets. In the first order rearrangement
operation, if a packet with a sequence number of n is received, the
packets of which sequence numbers are lower than n are delivered to
the upper layer although the order rearrangement has not been
completed yet. Whether to apply the second order rearrangement
operation is determined depending on whether an order rearrangement
timer is configured. That is, if an order rearrangement timer is
configured to a certain bearer, the UE applies the second order
rearrangement operation to the bearer always. In the second order
rearrangement operation, if a mission packet occurs, a timer starts
and, if the packet is not received before the expiry of the timer,
delivers the packets having the sequence numbers lower than that of
the mission packet to the upper layer. In the case of the bearer to
which both the first and second order rearrangements are
configured, the UE applies the first order rearrangement and then
the second order rearrangement. Or, the second order rearrangement
is not applied during the period in which the first order
rearrangement is applied, i.e. during a predetermined period after
the lower layer is reconfigured.
[0144] In the multi-PDCP structure too, a GTP tunnel for data
forwarding is established between the primary and non-primary eNBs
through which the DL PDCP SDU of the NP-EPS bearer is forward from
the P-ENB to the NP-ENB and the UL PDCP SDU from the NP-ENB to the
P-ENB.
[0145] FIG. 18 is a signal flow diagram illustrating the operation
of adding primary set and non-primary sets serving cells and
configuring DRB according to an embodiment of the present
invention.
[0146] In the mobile communication system composed of a UE 1805,
eNB 1 1815, and eNB 2 1810; cell a is controlled by the eNB 1, and
cells b and c are controlled by the eNB 2. The cell a is a macro
cell, and the cells b and c are pico cells. The PCell of the UE is
the cell a. The UE is configured with two EPS bearers. The DRB
identifier (DRB id) of the EPS bearer 1 is 10, the logical channel
identifier (LCH id) is 4, and the delay-sensitive real time
service, e.g. VoIP service, is provided. The DRB id of the EPS
bearer 2 is 11, the LCH id of the EPS bearer 2 is 5, and a burst
data communication service, e.g. file download service, is
provided. The UE transmits/receives data on DRB 10 and DRB 11
through the PCell at step 1820.
[0147] The P-ENB, i.e. the eNB 1, instructs the UE to measure the
cells b and c to configure the pico cells to the UE at step 1825.
The UE performs measurement as instructed and, if the channel
qualities of the cells fulfil a predetermined condition, reports
the measurement result to the eNB at step 1830. The eNB may notify
the UE of the frequencies to be measured instead of the cells. That
is, the eNB may instruct the UE to measure the frequencies of the
cells b and c at step 1825. The measurement result report is
carried in a predetermined RRC control message. The condition of
triggering the measurement result report is that the channel
quality of a neighboring cell operating on the frequency indicated
for measurement which is better than a predetermined threshold is
maintained during a predetermined period or that the channel
quality of a neighboring cell operating on the frequency indicated
for measurement which is better than that of the PCell is
maintained during a predetermined period
[0148] The P-ENB adds the pico cell of the eNB 2 as a SCell based
on the measurement result reported by the UE at step 1840 and
determines to communicate (or transmit) the EPS bearer 2 data
through the added SCell at step 1843.
[0149] The P-ENB sends the NP-ENB a control message requesting for
adding the SCell at step 1845. The control message may include at
least part of the informations listed in table 5.
TABLE-US-00005 TABLE 5 Name Description SCell candidate Identifiers
of cells that can be configured as SCell among cells info. of
NP-ENB and measurement results on the cells. The NP-ENB may
determine the cells to be configured SCell in consideration of the
measurement result and load statuses of the cells. If the coverages
of the pico cells controlled by one eNB are similar to each other,
the NP-ENB may configure a cell which is not the SCell candidate
cell recommended by the P-ENB as the SCell. TAG id info.
Information on the identifier of the TAG to be configured at the
drift eNB. In order to prevent the identifiers in use in the
serving eNB from being reused, the identifier is determined by the
serving cell and notified to the drift eNB. Offload bearer info.
Information on the EPS bearer to be offloaded in the non- primary
set serving cell. This includes required information, EPS bearer
identifier, and others as follows. The first PDCP distribution
structure: PDCP configuration information, RLC configuration
information, DRB id, and LCH information. The second PDCP
distribution structure: identical with the first PDCP distribution
structure. The first RLC distribution structure: RLC configuration
information, DRB id, and LCH information. The second RLC
distribution structure: RLC Tx entity configuration information DRB
id, and LCH information. The first MAC distribution structure: LCH
information. The second MAC distribution structure: LCH
information. The LCH information includes LCH id. The RLC and PDCP
configuration information and LCH information are defined in
RLC-config, PDCP-config, and logicalChannelConfig of TS36.331,
respectively. The RLC Tx entity configuration information is the
information on the transmission of the RLC-config. Call Admission
The serving eNB provides the drift eNB with reference Control info.
information in order to the drift eNB to determine whether to
accept or reject the SCell add request. For example, the reference
information may include the required data rate, estimated UL data
amount, expected DL data amount, etc. GTP Tunnel info. GTP Tunnel
information for use in UL data forwarding.
[0150] The NP-ENB performs Call Admission Control. If it is
determined to accept the SCell Add Request, the NP-ENB determines
the cell to be added as SCell and configures an NP-DRB. The NP-ENB
reuses the LCH id of the P-ENB in order for the UE to use only one
MAC entity. For example, the NP-ENB allocates the LCH id of 5 in
configuring part or whole of the DRB for the EPS bearer 2.
[0151] One of the important functions of the MAC entity at UE is to
multiplex the RLC PDUs of multiple DRBs into one MAC PDU and
demultiplex the MAC PDU into the RLC PDUs. For multiplexing and
demultiplexing, it is necessary to insert the LCH id in the MAC PDU
header appropriately. Accordingly, if the P-ENB and NP-ENB allocate
LCH id inconsistently, e.g. if the same LCH id is allocate to
different DRBs, the UE has to configure the MAC entities for the
P-ENB and NP-ENB independently. In the present invention, the
NP-ENB allocates the LCH id to the NP-DRB which the P-ENB has not
allocated to other DRB in order to avoid the above problem. For
example, the NP-ENB may allocate the LCH which has been used by the
P-ENB already for the corresponding DRB.
[0152] The NP-ENB allocates the DRB id of the NP-DRB which has been
used by the P-ENB. This is because, if a new DRB id is allocated to
the NP-DRB, the UE may determine that a new DRB is configured and
thus malfunction, e.g. discard the data stored in the DRB buffer or
deliver the data to the upper layer.
[0153] The NP-ENB configures the PDCP and RLC entities of the
NP-DRB by applying the PDCP and RLC configurations used in the
P-ENB. If a different configuration is used, the UE releases the
current DRB and reconfigures a DRB in adaptation to the new
configuration to avoid functioning.
[0154] In detail, the NP-ENB configures part or whole of the np-DRB
as follows.
[0155] In the first or second PDCP distribution structure, all of
the PDCP entity, the RLC entity, and the LCH are configured. In the
RLC distribution structure, the RLC entity and the LCH are
configured. In the second RLC distribution, the RLC Tx entity and
the LCH are configured. In the MAC distribution structure, the LCH
is configured. In the second MAC distribution structure, the low
RLC Tx entity and the LCH are configured.
[0156] The NP-ENB sends the P-ENB a control message of accepting
the SCell Add Request at step 1850. This control message may
include at least part of the informations listed in table 6.
TABLE-US-00006 TABLE 6 Name Description SCellToAddMod This is the
information on the SCells (e.g. cells b and c) configured by the
drift eNB and includes sCellIndex-r10, cellIdentification-r10,
radioResourceConfigCommonSCell-r10,
radioResourceConfigDedicatedSCell-r10, and TAG information. PUCCH
configuration At least one of the SCells belonging to the
non-primary set is info. for PUCCH SCell configured with Physical
Uplink Control Channel (PUCCH). The UL control information such as
HARQ feedback, Channel Status Information (CSI), Sounding Reference
Signal (SRS), and Scheduling Request (SR) is transmitted on the
PUCCH. Hereinafter, the SCell in which PUCCH is transmitted is
referred to as PUCCH SCell. This information includes the
sub-information such as PUCCH SCell identifier and PUCCH
configuration information. GTP Tunnel info. Information on the GTP
Tunnel to be used for DL data forwarding. UE identifier C-RNTI to
be used by UE in the SCells of the non-primary set. Hereinafter,
referred to as C-RNTI_NP. Bearer Information on the bearer to be
offloaded. This includes a list configuration info. of bearers
accepted to be offloaded and per-bearer configuration information.
If the bearer configurations are identical with each other, this
information may include only the list of the accepted bearers. The
following informations are included depending on the structure. The
first MAC distribution structure: RLC PDU size which is configured
in consideration of channel condition at the corresponding time and
may be updated by the NP-ENB. The second MAC distribution
structure: RLC PDU size which is adjusted by the low RLC entity
through re-segmentation so as to be set to relatively large value
and not changed after the initial configuration. MAC configuration
Various MAC configuration informations to be applied to the info.
non-primary set serving cells. For example, DRX information, PHR
configuration information, and BSR configuration information.
[0157] If the control message is received, the P-ENB sends the UE
an RRC control message instructing to add a serving cell at step
1855. The RRC control message may include at least part of the
informations listed in table 7. The P-ENB stops the NP-DRB data
communication as follows.
[0158] The first/second PDCP distribution structure, the
first/second RLC distribution structure: Stop NP-DRB DL data
transmission.
[0159] The first/second MAC distribution structure: Continue NP-DRB
DL data transmission
TABLE-US-00007 TABLE 7 Name Description SCellAddMod This is the
information transmitted by the drift eNB without modification. That
is, this is identical with SCellAddMod in table 6. This includes
one SCellAddMod per SCell and is a sub- information of the
SCellAddModList. PUCCH configuration This is the information
transmitted by the drift eNB without info. for PUCCH SCell
modification. That is, this is identical with the PUCCH information
for PUCCH SCell in table 6. Non-primary set This is the information
on the SCells belonging to the non-primary serving cell info. set
among the SCells to be configured. This may include SCell
identifiers and identifiers of TAGs belonging to the non-primary
set. UE identifier C-RNTI to be used by UE in the SCells of the
non-primary set, i.e. C-RNTI_NP. Offload bearer info. This is the
information on the bearer to be processed by the drift eNB. From
the view point of the UE, this is the information on the bearer for
communication through the serving cells of the non-primary set and
includes the bearer list and bearer configuration information. If
the bearer configurations are identical with each other, the bearer
configuration information may be omitted. The bearer identifier of
the bearer list may be the EPS bearer identifier, DRB id, or LCH
id. If DRB id, the value, e.g. 11, is signaled. MAC configuration
Various MAC configuration informations related to the non- info.
primary set serving cell. For example, DRX information, PHR
configuration information, and BSR configuration information.
[0160] If the RRC Connection Reconfiguration control message is
received, the UE configures SCell, PHR and BSR using the various
informations included in the control message at step 1857. If the
offload bearer information is included, the UE stops data
communication as follows.
[0161] The first or second PDCP distribution structure, the first
RLC distribution structure: Stop UL data transmission of NP-DRB
[0162] The second RLC distribution structure, the first or second
MAC distribution structure: Continue UL data transmission of
NP-DRB
[0163] In the case of the first or second PDCP distribution
structure or the first or second RLC distribution structure, the
first reconfiguration procedure is performed for the NP-DRB.
[0164] The UE establishes DL synchronization with the PUCCH SCell
and performs random access in the PUCCH SCell at step 1860. In more
detail, the UE transmits a random access preamble using a
predetermined frequency resource during a predetermined time period
of the PUCCH SCell and waits for receiving a random access response
message during a predetermined period determined according to the
preamble transmission time. If a valid random access response
message is received, the UE adjusts the uplink transmission timing
based on the UL transmission Timing Advance Command included in the
message. The UE transmits the MAC PDU through the PUCCH SCell using
the UL transmission resource indicated in the UL grant of the
message. The MAC PDU includes the C-RNTI MAC CE and BSR MAC CE, and
the C-RNTI MAC CE includes the C-RNTI_NP. The BSR MAC CE includes
the buffer status information indicating the transmittable data
amount stored in the offload bearer. The C-RNTI MAC CE and the BSR
MAC CE are specified in section 6.1.3 of TS 36.321. The UE
determines whether the PDCCH of the PUCCH SCell which indicates
initial transmission addressed to the C-RNTI_NP. If the PDCCH
fulfilling this condition is received during a predetermined
period, the UE determines that the random access has completed
successfully and thus resumes data transmission as follows.
[0165] In the first or second PDCP distribution structure or the
first or second RLC distribution structure, the PDCP STATUS REPORT
generated to the NP-DRB is transmitted to the non-primary set
serving cell.
[0166] The UE performs NP-DRB data communication through the newly
configured SCell at step 1865. In the first or second PDCP
distribution structure or the first or second RLC distribution
structure, the UE applies the set-specific logical channel
prioritization. In the first or second MAC distribution structure,
the UE applies the normal logical channel prioritization.
[0167] Upon receipt of the SCell Add Accept control message, the
P-ENB starts forwarding the DRB data to be offloaded to the NP-ENB.
The P-ENB sends the NP-ENB an SN Status message which may include
at least part of the informations listed in table 8 in association
with the NP-DRB fulfilling condition 1 at step 1870.
TABLE-US-00008 TABLE 8 Name Description UL PDCP PDU Bitmap having a
predetermined size. The nth bit indicates reception status info.
reception status of PDCP SDU having PDCP SN of m. m = PDCP SN of
first missing PDCP SDU + n) modulo (Max PDCP SN + 1) UL COUNT COUNT
of first missing PDCP SDU. The COUNT is a 32-bit integer and
increments by 1 for every PDCP SDU. The COUNT is a value obtained
by concatenating HFN and PDCP SN. DL COUNT COUNT to be granted to
the first PDCP SDU among the PDCP SDU to which no PDCP SN is
allocated yet.
[0168] [Condition 1]
[0169] The corresponding DRB operates in RLC AM mode and is
configured to generate PDCP STATUS REPORT.
[0170] The PDCP STATUS REPORT is a control message exchanged
between the PDCP Tx/Rx entities to avoid packet loss in the case
where the RLC cannot perform ARQ temporarily due to the RLC entity
reconfiguration.
[0171] The P-ENB forwards data to the NP-ENB at step 1875 as
follows.
[0172] First or Second PDCP Distribution Structure [0173] DL data:
Among the PDCP SDUs stored in the buffer, the PDCP SDUs of which
successful transmissions are not sure are delivered. [0174] The
PDCP SDUs which have allocated PDCP SNs already are transmitted to
the NP-ENB along with the GTP header including the allocated PDCP
SN information. [0175] The PDCP SDUs which have not allocated PDCP
SN yet are transmitted to the NP-ENB along with the GTP header
having no PDCP SN information [0176] UL data [0177] The PDCP SDUs
received successfully but not arranged in order are transmitted to
the NP-ENB. At this time, the GTP header includes the PDCP SN
information.
[0178] First or Second RLC Distribution Structure [0179] DL data:
Among the PDCP SDUs stored in the buffer, the PDCP SDUs of which
successful transmissions are not sure are processed into PDCP PDUs,
which are transferred. [0180] The PDCP PDUs which have allocated
the PDCP SN already are transmitted to the NP-eNB along with the
GTP header including the information indicating that the PDCP PDUs
are included. [0181] The PDCP SDUs which have not allocated PDCP SN
yet are processed into PDCP PDUs, which are transmitted to the
NP-ENB along with the GTP header including the information
indicating that the PDCP PDUs are included. [0182] The UL data is
not transferred.
[0183] The operations related to data communication in the
respective structures are summarized.
[0184] The First or Second PDCP Distribution Structure [0185] The
NP-ENB receives the SCell Add Request message at step 1845 and, if
the SCell add request is accepted, configures NP-DRB. [0186] If the
RRC Connection Reconfiguration control message is transmitted to
the UE at step 1885, the P-ENB stops DL data transmission on NP-DRB
and establishes an RLC entity. As a consequence, the UL RLC packets
stored in the RLC entity are reassembled into the PDCP PDUs, which
are transferred to the PDCP entity. [0187] If the RRC Connection
Reconfiguration control message is received at step 1885, the UE
stops uplink data transmission on the NP-DRB and reestablishes RLC
transmission/reception entity. As a consequence, the DL RLC packets
stored in the RLC reception entity are reassembled into PDCP PDUs,
which are transferred to the PDCP entity. [0188] The P-ENB sends
the NP-ENB the SN status information at step 1870. The SN status
information includes the information on the DL PDCP SDUs stored in
the PDCP transmission buffer and the UL PDCP SDUs stored in the
reception buffer. [0189] The P-ENB sends the NP-ENB the DL PDCP
SDUs through the GTP tunnel established for DL data forwarding and
the UL PDCP SDUs through the GTP tunnel established for UL data
forwarding at step 1875. [0190] The UE acquires DL synchronization
with the non-primary set serving cell and, if the random access
completes in the PUCCH SCell, transmits a PDCP Status Report
through the non-primary set serving cell. The PDCP Status Report is
generated by referencing the DL PDCP SDUs stored in the PDCP
reception buffer. [0191] The PDCP Status Report is generated by
referencing the UL PDCP SDUs stored in the UL PDCP reception buffer
or the SN status information. [0192] The UE and the NP-ENB resume
NP-DRB data communication using the transmission resource of the
non-primary set serving cell.
[0193] The First RLC Distribution Structure [0194] The NP-ENB
receives the SCell Add Request message at step 1845 and, if the
SCell add request is accepted, configures an RLC entity of the
NP-DRB. [0195] If the RRC Connection Reconfiguration control
message is transmitted to the UE at step 1885, the P-ENB stops DL
data transmission on NP-DRB and establishes an RLC entity. As a
consequence, the UL RLC packets stored in the RLC entity are
reassembled into the PDCP PDUs, which are transferred to the PDCP
entity. [0196] If the RRC Connection Reconfiguration control
message is received at step 1885, the UE stops uplink data
transmission on the NP-DRB and reestablishes RLC
transmission/reception entity. As a consequence, the DL RLC packets
stored in the RLC reception entity are reassembled into PDCP PDUs,
which are transferred to the PDCP entity. [0197] The P-ENB sends
the NP-ENB the SN status information at step 1870. The SN status
information includes the information on the DL PDCP SDUs stored in
the PDCP transmission buffer and the UL PDCP SDUs stored in the
reception buffer. [0198] The P-ENB sends the NP-ENB the DL PDCP
SDUs through the GTP tunnel established for DL data forwarding and
the UL PDCP SDUs through the GTP tunnel established for UL data
forwarding at step 1875. [0199] The UE acquires DL synchronization
with the non-primary set serving cell and, if the random access
completes in the PUCCH SCell, transmits a PDCP Status Report
through the non-primary set serving cell. The PDCP Status Report is
generated by referencing the DL PDCP SDUs stored in the PDCP
reception buffer. [0200] The P-ENB sends the UE a PDCP STATUS
REPORT. The PDCP STATUS REPORT is generated by referencing the UL
PDCP SDUs stored in the UL PDCP reception buffer or SN status
information. [0201] The UE and the NP-ENB resume data communication
of NP-DRB using the transmission resource of the non-primary set
serving cell.
[0202] The Second RLC Distribution Structure [0203] The NP-ENB
receives the SCell Add Request message at step 1845 and, if the
SCell add request is accepted, configures an RLC entity of the
NP-DRB. [0204] If the RRC Connection Reconfiguration control
message is transmitted to the UE at step 1885, the P-ENB stops DL
data transmission on NP-DRB and establishes an RLC entity. As a
consequence, the UL RLC packets stored in the RLC entity are
reassembled into the PDCP PDUs, which are transferred to the PDCP
entity. [0205] If the RRC Connection Reconfiguration control
message is received at step 1885, the UE stops uplink data
transmission on the NP-DRB and reestablishes RLC
transmission/reception entity. As a consequence, the DL RLC packets
stored in the RLC reception entity are reassembled into PDCP PDUs,
which are transferred to the PDCP entity. [0206] The P-ENB sends
the NP-ENB the SN status information at step 1870. The SN status
information includes the information on the DL PDCP SDUs stored in
the PDCP transmission buffer and the UL PDCP SDUs stored in the
reception buffer. [0207] The P-ENB sends the NP-ENB the DL PDCP
PDUs through the GTP tunnel established for DL data forwarding at
step 1875. [0208] The UE acquires DL synchronization with the
non-primary set serving cell and, if the random access completes in
the PUCCH SCell, transmits a PDCP Status Report through the
non-primary set serving cell. The PDCP Status Report is generated
by referencing the DL PDCP SDUs stored in the PDCP reception
buffer. [0209] The NP-ENB resumes np-DRB DL data communication
using the transmission resource of the non-primary set serving
cell.
[0210] The First or Second MAC Distribution Structure [0211] The
NP-ENB receives the SCell Add Request message at step 1845 and, if
the SCell add request is accepted, configures the logical channel
of the NP-DRB. [0212] The P-ENB continues DL data transmission of
NP-LCH without pause in the SCell add/release procedure. [0213] The
UE continues UL data transmission of NP-LCH without pause in the
SCell add/release procedure. [0214] The SN status report message
and PDCP STATUS REPORT are not used.
[0215] FIG. 19 is a signal flow diagram illustrating the procedure
of releasing SCell and transmitting/receiving data according to an
embodiment of the preset invention.
[0216] The UE transmits/receives data of the NP-DRB through the
non-primary set serving cell at step 1865.
[0217] The P-ENB 1815 forwards the NP-DRB DL data to the NP-ENB
1810, and the NP-ENB forwards the UL data to the P-ENB at step
1903.
[0218] The UE reports the measurement result notifying that the
channel quality of the non-primary set serving cell is less than a
predetermined threshold at step 1905. If the channel quality of
part of the non-primary set serving cell, e.g. channel quality of
the PUCCH SCell, is less than a predetermined threshold, the P-ENB
determines to release all the non-primary set serving cells at step
1907.
[0219] The P-ENB sends the NP-ENB a control message request for
release of the SCell of the UE 1905 at step 1910. Upon receipt of
the control message, the NP-ENB performs the following operations
at step 1913. [0220] If part of non-primary set serving cells are
released and the released cells include no PUCCH SCell [0221] The
NP-ENB transmits a predetermined MAC CE (Activation/Deactivation
MAC CE, see TS 36.321) to deactivate the released SCells. [0222]
The NP-ENB releases the SCells instructed to release. [0223] In the
case that part of non-primary set serving cells is released but the
PUCCH SCell is not included among the released serving cells (or
PUCCH SCell is absent due to the release of SCell) or all the
non-primary set serving cells are released [0224] The NP-ENB
transmits a MAC CE (hereinafter, referred to as first MAC CE) to
deactivate the SCells and prohibits UL transmission in the PUCCH
SCell. [0225] The NP-ENB releases all the non-primary set serving
cells. [0226] The NP-ENB stops NP-DRB data transmission/reception
[0227] The NP-ENB reestablishes RLC and PDCP entities. [0228] The
NP-ENB transmits SN status information at step 1945.
[0229] The first MAC CE is made up of a MAC sub-header without
payload to instruct the UE to perform the following operations.
[0230] To deactivate the serving eNBs with the exception of the
PUCCH SCell among the non-primary set serving cells in the active
state currently. [0231] To prohibit UL transmission in the PUCCH
SCell (e.g. Channel Quality Indicator (CQI), Scheduling Request,
and random access preamble)
[0232] The NP-ENB sends the P-ENB a control message for accepting
SCell release at step 1915.
[0233] The P-ENB sends the UE a control message instructing to
release the SCell at step 1920. The control message includes the
identifier of the SCell to be released. Upon receipt of the control
message, the UE performs the operations as follows. [0234] If part
of the non-primary set serving cells is released and if the
released serving cells include no PUCCH SCell [0235] release the
SCell indicated to release [0236] maintain data
transmission/reception on NP-DRB [0237] if part of non-primary set
serving cells is released and if the released serving cells include
the PUCCH SCell (i.e. the PUCCH SCell is absent due to the SCell
release) or if all the non-primary set serving cells are released,
[0238] release all the primary set serving cells at step 1925
[0239] stop NP-DRB data transmission/reception and perform the
first reestablishment at step 1930 [0240] resume NP-DRB data
transmission/reception. At this time, use only the primary set
serving cell transmission resource at step 1935. [0241] generate
PDCP STATUS REPORT for NP-DRB at step 2940
[0242] Afterward, the UE transmits/receives NP-DRB data through the
primary set serving cell at step 1955.
[0243] The NP-ENB sends the P-ENB an SN status information message
at step 1945 and forwards the data at step 1950.
[0244] The P-ENB performs NP-DRB communication with the UE using
the forwarded data at step 1955.
[0245] FIG. 20 is a signal flow diagram illustrating a procedure of
releasing the SCell and transmitting/receiving data according to
another embodiment of the present invention.
[0246] For example, the NP-ENB may determine whether to release the
SCell by referencing the CQI of the non-primary set serving
cell.
[0247] The UE reports the CQIs of the non-primary set serving cells
in the active state currently using the PUCCH transmission resource
of the PUCCH SCell at step 2005.
[0248] If CQIs of the non-primary set serving cells are maintained
in a bad state over a predetermined period or if the CQI of the
PUCCH SCell is maintained in a bad state over the predetermined
period, the NP-ENB determines to release the non-primary set
serving cell at step 2007. The NP-ENB sends the P-ENB a control
message instructing to release the SCell. Part or whole of the
configured SCells may be released according to the control message.
The NP-ENB performs the operation of step 1913. The subsequent
steps are identical with those of FIG. 19.
[0249] The data communication operation in the respective
structures can be summarized as follows.
[0250] The First or Second PDCP Distribution Structure [0251] If a
control message related to the release of all the SCells, e.g.
SCell Release Accept message 1915 or SCell Release message 2010 is
transmitted, the np-eNB stops transmitting the NP-DRB DL data and
reestablishes the RLC entity. As a consequence, the UL RLC packets
stored in the RLC reception entity are reassembled into the PDCP
PDUs, which are transferred to the PDCP entity. [0252] If the RRC
Connection Reconfiguration control message 1920 is received, the UE
stops transmitting the NP-DRB UL data and reestablishes the RLC
transmission/reception entity. As a consequence, the DL RLC packets
stored in the RLC reception entity are reassembled into the PDCP
PDUs, which are transferred to the PDCP entity. [0253] The UE
resumes the NP-DRB UL data transmission immediately and transmits
the PDCP STATUS REPORT through the primary set serving cell. [0254]
The NP-ENB sends the P-ENB an SN Status information at step 1945.
The SN status information includes the information on the DL PDCP
SDUs stored in the PDCP Tx buffer and the UL PDCP SDUs stored in
the Rx buffer. [0255] The NP-ENB forwards to the P-ENB the DL PDCP
SDUs through the GTP tunnel established for the DL data forwarding
and the UL PDCP SDUs through the GTP tunnel established for the UL
data forwarding at step 1950. [0256] The P-ENB sends the UE a PDCP
STATUS REPORT. The PDCP STATUS REPORT is generated by referencing
the UL PDCP SDUs stored in the UL PDCP Rx buffer or the SN status
information. [0257] The UE and the P-ENB resume the NP-DRB DL data
communication using the transmission resource of the primary set
serving cell.
[0258] The First RLC Distribution Structure [0259] If a control
message related to the release of all the SCells, e.g. SCell
Release Accept message 1915 or the SCell Release message 2010, is
transmitted, the NP-ENB stops transmitting the NP-DRB DL data and
reestablishes the RLC entity. As a consequence, the UL RLC packets
stored in the RLC Rx entity are reassembled into the RLC SDUs,
which are transferred to the PDCP entity of the P-ENB. [0260] If
the RRC Connection Reconfiguration control message is received at
step 1920, the UE stops transmitting the NP-DRB UL data and
reestablishes the RLC Tx/Rx entity. As a consequence, the DL RLC
packets stored in the RLC Rx entity are reassembled into the PDCP
PDUs, which are transferred to the PDCP entity. [0261] The UE
resumes the NP-DRB UL data transmission immediately and transmits a
PDCP STATUS REPORT through the primary set serving cell. [0262] The
NP-ENB sends the P-ENB the SN status information at step 1945. The
SN status information includes the information on the DL PDCP SDUs
stored in the PDCP Tx buffer and the UL PDCP SDUs stored in the Rx
buffer. [0263] The NP-ENB forwards the DL RLC SDUs to the P-ENB
through the GTP tunnel established for DL data forwarding and the
UL RLC PDUs through the GTP tunnel established for UL data
forwarding at step 1950. [0264] The P-ENB sends the UE a PDCP
STATUS REPORT. The PDCP STATUS REPORT is generated by referencing
the UL PDCP SDUs stored in the UL PDCP Rx buffer or the SN status
information. [0265] The UE and the P-ENB resume the NP-DRB DL data
communication using the primary set serving cell transmission
resource.
[0266] The Second RLC Distribution Structure [0267] If a control
message related to the release of all the SCells, e.g. SCell
Release Accept message 1915 or the SCell Release message 2010, is
transmitted, the NP-ENB stops transmitting the NP-DRB DL data and
reestablishes the RLC entity. As a consequence, the UL RLC packets
stored in the RLC Rx entity are reassembled into the RLC SDUs,
which are transferred to the PDCP entity of the P-ENB. [0268]
Although the RRC Connection Reconfiguration control message is
received at step 1920, the UE continues the NP-DRB UL data
transmission. The UE reestablishes the Rx entity while maintaining
the RLC Tx entity. As a consequence, the DL RLC packets stored in
the RLC Rx entity are reassembled into PDCP PDUs, which are
transferred to the PDCP entity. [0269] The NP-ENB sends the P-ENB
an SN status information at step 1945. The SN status information
includes the information on the DL PDCP SDUs stored in the PDCP Tx
buffer, i.e. DL COUNT. [0270] The NP-ENB forwards the DL RLC SDUs
to the P-ENB through the GTP tunnel established for DL data
forwarding at step 1950. [0271] The UE and the P-ENB resume the
NP-DRB DL data communication using the transmission resource of the
primary set serving cell.
[0272] The First or Second MAC Distribution Structure [0273] If a
control message related to the release of all the SCells, e.g.
SCell Release Accept message 1915 or the SCell Release message
2010, is transmitted, the NP-ENB releases the logical channel of
the NP-DRB. [0274] The P-ENB continues the DL data transmission of
NP-LCH without pause in the SCell add/release procedure. [0275] The
UE continues UL data transmission of the NP-LCH without pause in
the SCell add/release procedure. [0276] The SN status report
message and the PDCP STATUS REPORT are not used.
[0277] FIG. 21 is a diagram illustrating a ciphering/deciphering
procedure according to an embodiment of the present invention.
[0278] In the first PDCP and second distribution structures, the
NP-ENB performs ciphering/deciphering on the NP-DRB data. In the
ciphering/deciphering procedure, the PDCP Tx entity enters the
following inputs to a ciphering engine 2105 in which the EPS
Encryption Algorithm (EEA) is installed to generate the keystream
block 2110 having the same size as the plain text 2115 to be
ciphered.
[0279] COUNT denotes a 32-bit integer obtained by concatenating HFN
and PDCP SN. It is initialized to 0 and increments by 1 for every
PDCP SDU. BEARER relates to DRB id and acquired by subtracting 1
from the id of the DRB related to the PDCP SDU. DIRECTION is a
1-bit information which is determined depending on whether the data
is of DL or UL. LENGTH denotes the length of the required keystream
lock. KEY denotes a ciphering key derived from the keNB by means of
a predetermined algorithm and expressed as K.sub.UPenc.
[0280] By performing a predetermined operation, e.g. exclusive OR
operation, on the keystream block 2110 and the PDCP SDU 2115, the
ciphered text 2120 is generated. The PDCP Rx entity performs a
predetermined operation on the ciphered text (payload of PDCP PDU)
and the keystream block 2135 generated with the same process and
inputs to recover the original plain text 2140.
[0281] In the PDCP distribution structure, the NP-ENB ciphers the
DL PDCP SDU and decipher the UL PDCP SDU, and the NP-ENB has the
KEY too. If the NP-ENB and the P-ENB manage the KEY independently,
this increases the complexity of the UE and thus, in order to solve
this problem, the P-ENB provides the NP-ENB the information for use
in generating KEY and thus the NP-ENB generates KEY using this
information in the present invention.
[0282] In more detail, the P-ENB generates the KEY using the keNB,
a kind of root key. The UE and the eNB share the KeNB through the
call setup procedure or handover procedure so as to generate the
KEY based on the KeNB and perform ciphering/deciphering on the DRB
data.
[0283] If a certain DRB, e.g. DRB 11, is offloaded to the NP-ENB at
certain timing, the P-ENB provides the NP-ENB with the information
necessary for ciphering/deciphering. Examples of this information
are as follows. [0284] KeNB: Root key used for generating KEY in
use currently [0285] BEARER: Value obtained by decrementing DRB id
of NP-DRB by 1. In above example, this is 10. It is also possible
to notify of the DRB id to be allocated to the NP-DRB instead of
BEARER. [0286] COUNT: COUNT value used currently for NP-DRB. Both
the DL COUNT and UL COUNT are signaled.
[0287] The KeNB and BEARER (or DRB id) may be transmitted to the
NP-ENB through the SCELL Add Request control message 1845.
[0288] The COUNT may be transmitted to the NP-ENB through the SN
status information control message 1870.
[0289] The NP-ENB generates the KEY by inputting the KeNB to a
predetermined key generation function (Key Delivery Function
(KDF)). The KEY is used to cipher the NP-DRB DL data and decipher
the NP-DRB UL data.
[0290] The NP-ENB performs ciphering/deciphering on the NP-DRB data
using the BEARER value carried in the SCELL Add Request control
message other than the DRB id of the NP-DRB.
[0291] The NP-ENB determines the COUNT to be applied to the NP-DRB
DL PDCP SDU using the DL COUNT provided in the SN status
information control message. The COUNT is incremented by 1 whenever
a PDCP SDU is transmitted or ciphered.
[0292] The NP-ENB determines the COUNT to be applied to the NP-DRB
UL PDCP SDU using the UL COUNT provided in the SN status
information control message.
[0293] If it is determined to release the non-primary set serving
cell and moves the NP-DRB from the NP-ENB to the P-ENB at certain
timing, the NP-ENB sends the NP-eNB an SN status control message
1945. The SN status control message includes the DL COUNT and UL
COUNT. The NP-ENB sets the DL count to the COUNT to be applied to
the first DL PDCP SDU to which any PDCP SN is not applied yet. The
NP-ENB sets the UL COUNT to the COUNT to be applied to the first
missing PDCP SDU.
[0294] In the LTE mobile communication system, the mobility of the
UE in the connected state is controlled by the eNB. As far as the
eNB does not command handover, the UE performs the normal
operation, e.g. PDCP monitoring and PUCCH transmission. If the
serving radio link state goes bad such that the normal
communication is impossible before transmitting handover command to
the UE due to an unexpected error, the UE falls into the deadlock
state. In order to avoid this problem, the UE monitors the channel
condition of the current serving cell and, if a predetermined
condition is fulfilled, controls its mobility by itself. This is
referred to as radio link monitoring.
[0295] The UE performs the radio link monitoring to the primary set
and the non-primary set independently. The UE monitors the channel
conditions of predetermined primary and non-primary sets serving
cells, e.g. PCell and PUCCH SCell. If the channel conditions which
are equal to or less than a predetermined threshold lasts over a
predetermined period, the UE determines that a radio link problem
is detected.
[0296] The radio link problem detection condition is as
follows.
[0297] <PCell Radio Link Problem Detection Condition>
[0298] The out-of-sync indicator for the PCell occurs as many as
first N310 times successively. The out-of-sync indicator for the
PCell occurs when the PDCCH error rate calculated based on the
reception quality of a predetermined channel or signal (e.g. Cell
Reference Signal) of the PCell is equal to or greater than a
predetermined threshold, e.g. 10%, lasts over a predetermined
period, e.g. 200 ms.
[0299] The UE acquires the first N310 from the SIB2 of the
PCell.
[0300] <PUCCH SCell Radio Link Problem Detection
Condition>
[0301] The out-of-sync indicator for the PUCCH SCell occurs as man
as second N310 times successively. The out-of-sync indicator for
the PUCCH SCell occurs when the PDCCH error rage calculated based
on the reception quality of a predetermined channel or signal (e.g.
Cell Reference Signal) of the PUCCH SCell is equal to or greater
than a predetermined threshold, e.g. 10%, lasts over a
predetermined period, e.g. 200 ms.
[0302] The UE acquires and uses the second N310 as follows.
[0303] <Second N-310 Acquisition/Utilization Method>
[0304] A certain second N310 is transmitted to the UE in the RRC
Connection Reconfiguration message 1920 for configuring the PUCCH
SCell.
[0305] The UE uses the second N310 to a predetermined time point.
The predetermined time point is the time when the UE receives the
system information of the PUCCH SCell and acquires the second N310
from the system information of the PUCCH SCell.
[0306] The UE uses the second N310 from a predetermined time
point.
[0307] The UE may use a PUCCH SCell radio link problem detection
condition 2.
[0308] <PUCCH SCell Radio Link Problem Detection
Condition>
[0309] If the pathloss calculated based on a predetermined channel
or signal (e.g. Cell Reference Signal) of the PUCCH SCell and the
transmission power of the signal is equal to or greater than a
predetermined threshold, it is determined that the radio link
problem is detected. The UE may apply the layer 3 filtering (TS
36.331 5.5.3.2) to the pathloss calculation.
[0310] The radio link problem detection threshold value may be
transmitted to the UE in the RRC Connection Reconfiguration message
1920 for configuring the PUCCH SCell.
[0311] FIG. 22 is a diagram illustrating the radio link monitoring
procedure according to an embodiment of the present invention.
[0312] If a radio link problem is detected as denoted by reference
numbers 2205 and 2210, the UE determines whether the serving cell
in which the radio link problem has been detected is the PCell or
the PUCCH SCell to operate as follows.
[0313] If the serving cell in which the radio link problem has been
detected is the PCell, the UE stops the UL transmission in the
primary set serving cell and starts the first T310 timer. The first
T310 timer is broadcast in the SIB2 of the PCell.
[0314] If the serving cell in which the radio link problem has been
detected is the PUCCH SCell, the UE stops the UL transmission in
the non-primary set serving cell, e.g. PUCCH transmission in the
PUCCH SCell and the SRS transmission in the non-primary set serving
cell, and deactivates the non-primary set serving cells. At this
time, the UE keeps running sCellDeactivationTimer of the serving
cells deactivated. The UE starts the second T310 timer, and the
second T310 timer is acquired and used as follows.
[0315] <Second T310 Acquisition/Utilization Method>
[0316] The second T310 is transmitted to the UE in the RRC
Connection Reconfiguration message 1920 for configuring the PUCCH
SCell.
[0317] The UE uses the second T310 to a predetermined time point.
The predetermined time point is the time when the UE receives the
system information of the PUCCH SCell and acquires the second T310
from the system information of the PUCCH SCell.
[0318] The UE uses the second T310 to a predetermined time
point.
[0319] While the T310 is running, the UE monitors to determine
whether the related serving is recovered.
[0320] <PCell Radio Link Recovery Condition>
[0321] The in-sync indicator for the PCell occurs as many as first
N311 times successively. The in-sync indicator for the PCell occurs
when the PDCCH error rate calculated based on the reception quality
of a predetermined channel or signal (e.g. Cell Reference Signal)
of the PCell is equal to or greater than a predetermined threshold,
e.g. 5%, lasts over a predetermined period, e.g. 100 ms.
[0322] The UE acquires the first N311 from the SIB2 of the
PCell
[0323] <PUCCH SCell Radio Link Recovery Condition>
[0324] The in-sync indicator for the PUCCH SCell occurs as many as
second N311 times successively. The in-sync indicator for the PUCCH
SCell occurs when the PDCCH error rate calculated based on the
reception quality of a predetermined channel or signal (e.g. Cell
Reference Signal) of the PUCCH SCell is equal to or greater than a
predetermined threshold, e.g. 5%, lasts over a predetermined
period, e.g. 100 ms.
[0325] The second N311 acquisition and utilization method is
identical with the second N310 acquisition and utilization
method.
[0326] If the radio link recovery condition is fulfilled, the UE
determines whether the cell in which the radio link recovery is
detected is the PCell or the PUCCH cell to operate as follows.
[0327] If the serving cell in which the radio link recovery is
detected is the PCell, the UE resumes UL transmission of the
primary set serving cell and maintains the current RRC connection.
If the serving cell in which the radio link recovery is detected is
the PUCCH SCell, the UE resumes the UL transmission of the
non-primary set serving cell, e.g. PUCCH transmission of PUCCH
SCell and SRS transmission of the non-primary set serving cell and
activates the SCells for of which sCellDeactivationTimer is running
yet among the non-primary set SCells in the active state before
starting the T310.
[0328] If the serving cell is not recovered until the T310 expires,
the UE determines whether the serving cell of which T310 has
expired is the PCell or the PUCCH SCell to operate as follows. If
the serving cell of which T310 has expired is the PCell, the UE
declares radio link failure and starts the firs T311. The UE stops
UL transmission of the non-primary set serving cell too and starts
the RRC connection reestablishment procedure. The RRC connection
reestablishment procedure is of searching for the cell in which the
UE resumes communication and exchanges predetermined RRC control
messages with the cell to resume the RRC connection as specified in
TS 36.331 5.3.7. The first T311 timer is broadcast in the SIB2 of
the PCell. If the serving cell of which T310 has expired is the
PUCCH SCell, the UE determines that the non-primary set serving
cells cannot be used anymore and generates a predetermined RRC
control message. The RRC control message may include the
measurement result for the PUCCH SCell or the information notifying
that radio link problem has occurred in the PUCCH SCell.
[0329] If the serving cell is recovered before expiry of the T311,
the UE stops T311 and determines whether the recovered serving cell
is the PCell or the PUCCH SCell to operate as follows. If the
serving cell recovered before expiry of the T311 is the PCell, i.e.
if any cell for resuming communication is found before the expiry
of the T311, the UE initiates RRC Connection Reestablishment
procedure with the sell. If the serving cell recovered before
expiry of the T311 is the PUCCH SCell, the UE sends the eNB an RRC
control message including the information indicating that the PUCCH
SCell has been recovered through the primary set serving cell.
[0330] If the T311 expires at the time 2235 and 2240, the UE
determines whether the serving cell of which T311 has expired is
the PCell or the PUCCH SCell to operate as follows. If the serving
cell of which T311 has expired is the PCell, the UE transitions to
the idle state and notifies the upper layer that the RRC connection
has been released due to radio channel problem. If the serving cell
of which T311 has expired is the PUCCH SCell, the UE releases the
corresponding non-primary set serving cells and sends the eNB an
RRC control message including the information indicating that the
non-primary set serving cells have been released through a primary
set serving cell.
[0331] A modified PUCCH SCell radio link monitoring operation may
be taken.
[0332] <Modified PUCCH SCell Radio Link Monitoring
Operation>
[0333] If radio link problem is detected, the UE stops UL
transmission but monitors PDCCH in the non-primary set serving
cell. If PDSCH is scheduled, the UE receives and processes PDSCH.
However, the UE does not transmit HARQ feedback. If the PUCCH SCell
is not recovered until the T310 expires, the UE start T311 and
deactivates the non-primary set serving cells. The UE monitors to
detect when the PUCCH SCell is recovered while the T311 is running.
If there is no serving cell recovered among the non-primary set
serving cells until the T311 expires, the UE releases the
non-primary set serving cells. If there is at least one cell
recovered before expiry of the T311, the UE stops the T311 and
transmits an RRC control message to report the recovery.
[0334] The radio link failure may be declared due to various events
as well as expiry of T310. The UE declares radio link failure
differently depending on whether any non-primary set serving cell
is configured or not.
[0335] FIG. 23 is a flowchart illustrating an RLF detection
procedure according to an embodiment of the present invention.
[0336] Referring to FIG. 23, the UE starts RLF detection operation
at step 2305. The RLF detection operation starts upon the RRC
connection is configured to the UE and continues until the RRC
connection is released.
[0337] The UE determines whether any non-primary set serving cell
is configured currently at step 2310. If so, the procedure goes to
step 2330 and, otherwise, step 2315.
[0338] At step 2315, the UE determines whether the T310 has expired
currently and, if so, the procedure goes to step 2345 and,
otherwise, step 2320. At step 2320, the UE determines whether any
random access problem has occurred and, if so, the procedure goes
to step 2345 and, otherwise, step 2325. As described above, if the
random access fails in the PCell (in detail, if the random access
fails in spite of transmitting the preamble PreambleTransMax times
in the PCell), the UE determines that the RLF has occurred. At step
2325, the UE determines whether there is any bearer of which RLC
maximum transmission (or retransmission) count has reached the
limit among all the radio bearers configured currently. If there is
any bearer of which RLC maximum transmission count has reached the
limit, this means that a significant error has occurred on in UL
and thus the procedure goes to step 2345. If there is no bearer of
which RLC maximum transmission count has reached the limit, the UE
returns the procedure to step 2305. In summary, if at least one of
the above three conditions is fulfilled, the UE determines that the
RLF has occurred and thus the procedure goes to step 2345 and,
otherwise none of the three conditions is fulfilled, step 2305 to
continue the RLF detection operation.
[0339] If any non-primary set is configured at step 2310, the
procedure goes to step 2330. At step 2330, the UE determines
whether the T310 of the PCell has expired and, if so, the procedure
goes to step 2345 and, otherwise, step 2335. The UE does not
consider the expiry of the T310 of a cell other than PCell, e.g.
PUCCH SCell. At step 2335, the UE determines whether any problem
has occurred in the random access in the PCell. If so, the
procedure goes to step 2345 and, otherwise, step 2340. At step
2340, the UE determines whether there is any bearer of which RLC
maximum transmission (or retransmission) count has reached the
limit among the P-DRB and SRB (Signaling Radio Bearer; radio bearer
carrying RRC messages). If so, the procedure goes to step 2345 and,
otherwise, step 2305 to continue the RLF monitoring operation.
Although there is any bearer of which RLC maximum transmission
(retransmission) count has reached the limit among the NP-DRBs,
this is not determined that any condition of step 2340 has been
fulfilled. In summary, if at least one of the above three
conditions is fulfilled, the procedure goes to step 2345 and,
otherwise none of the three conditions is fulfilled, step 2305 to
continue the RLF monitoring operation.
[0340] Whether the RLC maximum transmission (or retransmission)
count has reached the limit may be considered only when any
non-primary set serving cell is not configured. That is, when the
condition is fulfilled at step 2335, the UE may skip step 2340 and
return the procedure to step 2305 immediately.
[0341] At step 2345, the UE generates the information to be
included in the RLF report. The RLF report is an RRC control
message which includes the information on the situation when the
RFL has occurred and which is transmitted from the UE to the eNB
after the RLC connection is reconfigured in order to check the
network problem afterward. The RLF report includes the information
as follows: identifier of Registered PLMN (RPLMN) at the time when
the RLF has occurred, DL channel measurement result for serving
cell (or PCell) at the time when the RLF has occurred or the last
serving cell (or PCell) at the time when the RLF has occurred, DL
channel measurement result for the neighboring cell at the time
when the RLF has occurred, and GPS coordinates information at the
time when the RLF has occurred.
[0342] At step 2350, the UE starts the RRC Connection
Reestablishment procedure.
[0343] In the PDCP distribution structure or the RLC distribution
structure, the UE performs set-specific logical channel
prioritization or Component Carrier-specific logical channel
prioritization. The set-specific logical channel prioritization is
to determining the data to be transmitted depending on the serving
cell through which the UL grant has been received.
[0344] FIG. 24 is a flowchart illustrating the LCP procedure
according to an embodiment of the present invention.
[0345] The UE receives an RRC Connection Reconfiguration message at
step 2405. The RRC Connection Reconfiguration message may be of
configuring non-primary set serving cells. The UE determines
whether there is any NP-LCH as a result of the RRC connection
reconfiguration at step 2410 and, if so, the procedure goes to step
2420 and, otherwise, step 2415. As a result of the RRC Connection
Reconfiguration, the NP-LCH may be changed for the P-LCH or the
P-LCH to the NP-LCH; and the whether the logical channel is the
P-LCH or NP-LCH is indicated by a b-bit indicator in the case of
DRB, and the P-LCH is used always in the case of SRB. At step 2415,
the UE determines the data to be transmitted with the application
of the normal LCP when a UL grant is received afterward. The normal
LCP is of determining the data to be transmitted in consideration
of the priority and amount of the transmission data without
consideration of the serving cell through which the UL grant has
been received or to which the UL grant has been addressed.
[0346] At step 2420, the UE determines the NP-LCG. The LCG is a
unit of the buffer status report and a set of one or more LCHs. The
eNB sorts the LCHs having similar priorities into an LCG and
signals the LCHs and the LCG including the LCHs to the UE using a
predetermined control message. The UE determines the LCG including
only the NP-LCHs as the NP-LCH among the LCGs.
[0347] The UE determines the P-LCH at step 225. The P-LCH is the
LCG made up of only the P-LCHs.
[0348] If a UL grant is received through a certain serving cell at
step 2430, the procedure goes to step 2435. At step 2435, the UE
determines whether the serving cell through which the UL grant has
been received is a primary set serving cell. Or, the UE may
determine whether the UL grant is associated with a primary set
serving cell. If the UL grant is associated with a primary set
serving cell, the UE performs primary set LCP on the P-LCH at step
2445. If the UL grant is not associated with a primary set serving
cell (i.e. associated with a non-primary set serving cell), the UE
performs non-primary set LCP on the NP-LCH at step 2440.
[0349] <Primary Set LCP>
[0350] The UE determines the data to be transmitted in
consideration of the priority among the data to be transmitted
through the primary set serving cells. The priority is as
follows.
[0351] 1. Common Control Channel Service Data Unit (CCCH SDU) such
as C-RNTI MAC CE or RRC Connection Request message or RRC
Connection Reestablishment Request message
[0352] 2. Regular BSR or periodic BSR including buffer status of
P-LCG (or BSR which is not padding BSR)
[0353] 3. Power Headroom Report (PHR) for primary set serving
cells
[0354] 4. Data transmittable through P-LCH with the exception of
CCCH
[0355] If there is data corresponding to the case of 1/2/3, the UE
determines whether to transmit the data as follows.
[0356] The UE compares the amount of the allocated transmission
resource in the order from case 1 or transmittable data amount with
the amount of the data to be transmitted. If there is any data to
be transmitted and if the amount of the data to be transmitted is
greater than the transmittable data amount, the UE checks the next
priority and, otherwise, allocates the transmission resource fit
for the data to be transmitted and updates the transmittable data
amount.
[0357] If there is transmission data remained after the resource
allocation for the case 1/2/3, the UE allocates the remained
transmission resource for the data corresponding to case 4
according to the priority until the transmission resource
exhausts.
[0358] <Non-Primary Set LCP>
[0359] The UE determines the data to be transmitted among the data
to be transmitted through the primary set serving cells in
consideration of priority. The priority is as follows.
[0360] 1. Regular BSR or periodic BSR including buffer status of
NP-LCG (or BSR which is not padding BSR)
[0361] 2. Power Headroom Report (PHR) for non-primary set serving
cells
[0362] 3. Data transmittable through NP-LCH
[0363] If the data of case 1/2 exist, the UE determines whether to
transmit the data as follows.
[0364] The UE compares the amount of the allocated transmission
resource in the order from case 1 or transmittable data amount with
the amount of the data to be transmitted. If there is any data to
be transmitted and if the amount of the data to be transmitted is
greater than the transmittable data amount, the UE checks the next
priority and, otherwise, allocates the transmission resource fit
for the data to be transmitted and updates the transmittable data
amount.
[0365] If there is transmission data remained after the resource
allocation for the case 1/2, the UE allocates the remained
transmission resource for the data corresponding to case 3
according to the priority until the transmission resource
exhausts.
[0366] The PHR is reported for the eNB to check the UL transmission
power status of the UE in scheduling the UL transmission in a
certain serving cell. The PHR includes the information on the
maximum transmission power of the UE allowed for the serving cell
and difference between the maximum allowed power and the current
transmission power (power headroom). The primary set serving cells
are scheduled by the P-ENB, and the non-primary set serving cells
are scheduled by the NP-ENB. Accordingly, the PHRs for the primary
and non-primary sets serving cells have to be transmitted to the
p-eNB and the NP-ENB respectively. In the present invention, if PHR
is triggered at a certain time point, the UE operates in
consideration of whether the PHR is the PHR for the primary set
serving cells (P-PHR) or the PHR for the non-primary set serving
cells (NP-PHR).
[0367] FIG. 25 is a signal flow diagram illustrating the PHR
trigger and transmission procedure according to an embodiment of
the present invention.
[0368] Referring to FIG. 25, if PHR is triggered at step 2520, the
UE 2505 generates and transmits the PHR at step 2530 at the first
transmission time, i.e. upon receipt of UL grant of allocating the
transmission resource amble enough to transmit the PHR from the
NP-ENB or the P-eNB at step 2525. The UE transmits both the primary
set serving cell PHR (P-PHR) and the non-primary set serving cell
PHR (NP-PHR) and, if the PHR is received, the eNB transmits the PHR
necessary for the other eNB, e.g. P-PHR, to the eNB, e.g. P-ENB, at
step 2535. At this time, the NP-ENB may send the counterpart eNB
the information on the time related to the PHR, e.g. the SFN of the
subframe in which the P-PHR has been received successfully and the
subframe number or the SFN of the subframe at which the first
transmission of the MAC PDU including the P-PHR has started and the
subframe number. Upon receipt of the PHR information, the P-ENB
checks the channel condition of the UE using the received
information. If the PHR is transmitted to the P-ENB through the
primary set serving cell, the P-ENB sends the NP-ENB the NP-PHR
along with the time information.
[0369] In another scheme, if the PHR is triggered, the UE generates
and transmits the PHR through the primary set serving cell one time
and then transmits the PHR one more time through the non-primary
set serving cell. If the PHR is triggered, the UE waits until a UL
grant for allocating the transmission resource amble enough to
transmit the PHR. If the UL grant fulfilling the above condition is
received at step 2545, the UE generates the PHR including both the
P-PHR and the NP-PHR and transmits the PHR at step 2550. If no
non-primary set serving cell is configured, the UE transmits the
PHR and cancels the triggered PHR. If any non-primary set serving
cell is configured, the UE transmits the PHR but does not cancel
the triggered PHR immediately; and only when the PHR has been
transmitted through both the primary and non-primary sets serving
cells during a predetermined period, the UE cancels the PHR. If the
PHR is cancelled but not transmitted through both the two types of
sets and if the UL grant is received through the set through which
the PHR has not been transmitted, the PHR is triggered again. Since
the PHR has been transmitted to only the NP-ENB, or through only
the non-primary set serving cell, the UE waits without cancelling
the PHR and, if the UL grant allocating transmission resource ample
enough to transmit the PHR is received from the p-eNB at step 2555,
the UE cancels the PHR after transmitting the P-PHR and NP-PHR to
the primary set serving cell.
[0370] In another scheme, the UE manages the PHR trigger per set
and, after transmitting the PHR to the serving cell of the set in
which the PHR has been triggered, cancel the PHR.
[0371] For example, if the NP-PHR is triggered at step 2565 and if
a UL grant allocating transmission resource ample enough to
transmit the NP-PHR is received from the non-primary set serving
cell at step 2570, the UE generates and transmits the NP-PHR at
step 2575 and cancels the NP-PHR. Afterward, if the P-PHR is
triggered at a certain time point at step 2580 and if a UL grant
allocating transmission resource amble enough to transmit the P-PHR
is received from the primary set serving cell at step 2585, the UE
generates and transmits the P-PHR at step 2590 and cancels the
P-PHR.
[0372] If PHR is triggered at step 2520 or 2540, this means that
one of the following conditions is fulfilled.
[0373] <PHR Trigger Condition> [0374] The displacement of the
pathloss of the serving cell fulfilling the following conditions is
equal to or greater than a predetermined threshold value. [0375]
Serving cell in active state [0376] Serving cell configured as
pathloss reference cell [0377] Serving cell in which the UE has
been allocated transmission resource for UL transmission. [0378]
PHR is triggered when a predetermined timer expires. The timer
restarts whenever the PHR is transmitted. [0379] The serving cell
configured with UL is activated
[0380] If a certain cell A is configured as the pathloss reference
cell of another cell B, this means that the pathloss of the cell A
is referenced to set the UL transmission power of the cell B. The
eNB may configure the pathloss relationship using a predetermined
control message.
[0381] If the NP=PHR is triggered at step 2565, this means that one
of the following conditions is fulfilled.
[0382] <NP-PHR Trigger Condition> [0383] The displacement of
the pathloss of the serving cell fulfilling the following
conditions is equal to or greater than a predetermined threshold
value. The predetermined threshold value is configured by the RRC
Connection Reconfiguration message 1855. [0384] Non-primary set
serving cell in active state [0385] Serving cell configured as
pathloss reference cell [0386] Serving cell in which the UE has
been allocated transmission resource for UL transmission. [0387]
PHR is triggered when a predetermined timer expires. The timer
restarts whenever the NP-PHR is transmitted. The timer is
configured by the RRC Connection Reconfiguration message 1855.
[0388] The non-primary set serving cell configured with UL is
activated
[0389] If P-PHR is triggered at step 2580, this means that one of
the following conditions is fulfilled.
[0390] <P-PHR Trigger Condition> [0391] The displacement of
the pathloss of the serving cell fulfilling the following
conditions is equal to or greater than a predetermined threshold
value. [0392] Primary set serving cell in active state [0393]
Serving cell configured as pathloss reference cell [0394] Serving
cell in which the UE has been allocated UL transmission resource
[0395] PHR is triggered when a predetermined timer expires. The
timer restarts whenever the P-PHR is transmitted. The timer is
configured by the RRC Connection Reconfiguration message 1855.
[0396] The primary set serving cell configured with UL is
activated
[0397] The PHR is a kind of a MAC CE and consists of a MAC
sub-header and the payload. The MAC sub-header includes a Logical
Channel ID (LCID) indicating the type of the MAC CE, and the
payload includes Power Headroom (PH) information and maxim transmit
power (PCMAX) information.
[0398] The PHR is formed in one of a normal PHR format and an
extended PHR format. The normal PHR format contains the PH
information for one serving cell with 1-byte payload and defined as
11010. The extended PHR format contains PH informations of multiple
serving cells and PCMAX information with the payload variable in
length and defined as 11001.
[0399] In the present invention, the P-PHR and NP-PHR are
discriminated based on the position of the PHR or the serving cell
in which the PHR has been transmitted without use of extra
LCID.
[0400] For example, if one MAC PDU includes two PHR, the first PHR
is the P-PHR and the second the N-PHR. If the MAC PDU transmitted
through a primary set serving cell includes one PHR, the PHR is the
P-PHR. If the MAC PDU transmitted through a non-primary set serving
cell, the PHR is the NP-PHR.
[0401] The P-PHR may be formed in the normal PHR format or the
extended PHR format. Whether the P-PHR is formed in the normal
format or the extended format is indicated in the RRC Connection
Reconfiguration message 520 related to the primary set serving
cell.
[0402] The NP-PHR may be formed in the normal PHR format or the
extended PHR format. Whether the NP-PHR is formed in the normal
format or the extended format is indicated in the RRC Connection
Reconfiguration message 635 related to the non-primary set serving
cell.
[0403] FIG. 26 is a diagram illustrating a PHR format according to
an embodiment of the present invention.
[0404] The normal P-PHR 2605 is defined by the LCID 11010 and
contains 6-bit PH information. The 6-bit PH field contains the type
1 PH of PCell. The type 1 PH is a value indicating difference
between the PCMAX of a certain serving cell and the PUSCH required
transmit power for the corresponding cell and specified in table
6.1.3.6.-1 of TS 36.321.
[0405] The normal NP-PHR 2625 is defined by the LCID 11010 and
contains 6-bit PH information. The 6-bit PH field contains the type
1 PH of PUCCH SCell. The type 1 PH contains a value indicating
difference between the PUSCH required transmit power for the PUCCH
SCell and the PCMAX of the PUCCH SCell.
[0406] The extended P-PHR 2610 is defined by the LCID 11001 and of
which first byte contains a bitmap indicating the primary set
SCells for which the PH informations are included. For example, if
the C1 bit is set to 1, this means that the PH information for the
SCell of which index is 3 is included.
[0407] If a predetermined condition is fulfilled, the type 2 PH
2611 of PCell is included. If the simultaneous transmission of
PUSCH and PUCCH is configured for primary set, or PCell, this means
that the condition is fulfilled. The simultaneous transmission of
PUSCH and PUCCH may be possible or not depending on the hardware
configuration of the UE. The UE reports its capability according to
a command from the eNB, the capability information including the
information on whether the simultaneous transmission of PUSCH and
PUCCH is supported.
[0408] The type 2 PH is a value obtained by subtracting the sum of
the PUSCH required transmit power and PUCCH required transmit power
from the PCMAX for the PCell or PUCCH SCell.
[0409] The PCMAX 2612 is contained if the PUCCH transmission is
scheduled in the PCell in the subframe supposed to carry the P-PHR
and, otherwise, not contained. The presence/absence of the PCMAX is
indicated by a V field associated therewith.
[0410] The type 1 PH 2613 of PCell is a field existing always and
filled with the value obtained by subtracting the PUCCH transmit
power from the PCMAX of the PCell.
[0411] The PCMAX 2614 is contained if the PUSCH transmission is
scheduled in the PCell in the subframe supposed to carry the P-PHR
and, otherwise, not contained.
[0412] Afterward, the PHs of the primary set SCells in the active
state are contained in the subframe supposed to carry the P-PHR in
an ascending order of the SCell index. If there is any PUSCH
transmission scheduled in the corresponding SCell, the PCMAX
occupies a byte following the byte occupied by the PHs.
[0413] The extended NP-PHR 2630 is defined by LCID 11001 and of
which first type is contains a bitmap indicating the non-primary
set SCells for which the PH informations are included. For example,
if the C7 bit is set to 1, this means that the PH information for
the SCell of which index is 7 is included.
[0414] If a predetermined condition is fulfilled, the type 2 PH
2631 of the PUCCH SCell is included. If the simultaneous
transmission of PUSCH and PUCCH is configured for non-primary set,
or PUCCH SCell, this means that the condition is fulfilled. The
simultaneous transmission of PUSCH and PUCCH may be possible or not
depending on the hardware configuration of the UE. The UE reports
its capability according to a command from the eNB, the capability
information including the information on whether the simultaneous
transmission of PUSCH and PUCCH is supported.
[0415] The PCMAX 2632 is contained if the PUCCH transmission is
scheduled actually in the PCell in the subframe supposed to carry
the NP-PHR and, otherwise, not contained. The presence/absence of
the PCMAX is indicated by a V field associated therewith.
[0416] The type 1 PH 2633 of PUCCH SCell is a field existing always
and filled with the value obtained by subtracting the PUSCH
transmit power from the PCMAX of the PUCCH SCell.
[0417] The PCMAX 2634 is contained if the PUSCH transmission is
scheduled actually in the PUSCH SCell in the subframe supposed to
carry the NP-PHR and, otherwise, not contained.
[0418] Afterward, the PHs of the non-primary set SCells in the
active state are contained in the subframe supposed to carry the
NP-PHR in an ascending order of the SCell index. If there is any
PUSCH transmission scheduled actually in the corresponding SCell,
the PCMAX occupies a byte following the byte occupied by the
PHs.
[0419] Each of the P-ENB and the NP-ENB cannot check the UL
scheduling status of the counterpart eNB. This may cause a problem
in that the total transmit power of the UE exceeds the maximum
allowed transmit power in the case that the P-ENB and the NP-ENB
schedule UL transmission in the same time duration. In order to
avoid this problem, the present invention proposes a method for the
NP-ENB and the P-ENB to use eNB-specific dedicated time periods and
common time period.
[0420] FIG. 27 is a signal flow diagram illustrating a procedure of
determining a subframe pattern according to an embodiment of the
present invention.
[0421] The P-ENB 2715 determines to add serving cells of the NP-ENB
2710 to the UE at a certain time point. The P-ENB sends the UE a
control message instructing to measure the non-primary set serving
cell to check whether any NP-ENB serving cell around at step 2725.
The control message is identical with the control message 1815 and
may further include the information instructing to report the
timing difference between a predetermined reference cell and the
non-primary set serving cell. The reference cell may be the
PCell.
[0422] Upon receipt of the control message, the UE performs
measurement on the cell or frequency indicated by the P-ENB. If the
measurement result of the best cell fulfils a predetermined
condition, the UE checks the timing difference of the cells and
acquires TDD UL/DL configuration information.
[0423] The TDD UL/DL configuration information is the information
of specifying the pattern of the UL and DL subframes in the
corresponding cell and specified in table 4.2-2 of TS 36.211.
[0424] FIG. 28 is a diagram illustrating a timing difference
according to an embodiment of the present invention.
[0425] The timing difference between the reference cell and a
certain neighbor cell is defined as a distance 2805 between a
predetermined subframe, e.g. subframe 0, of the PCell and the same
subframe of a neighbor cell or difference between SFNs to which the
subframe belongs, e.g. {[x+1]-[y+1]}.
[0426] The UE sends the P-ENB the measurement result report
message. This message is identical with the message 1820 and may
further include the timing difference between the reference cell
and a neighbor cell and the TDD UL/DL configuration information of
the neighbor cell.
[0427] The P-ENB determines P-ENB-specific subframes,
NP-ENB-specific subframes, and common subframes based on the above
information. These informations may be formatted as a bitmap of 40
or 70 bits. The first bitmap informs of the P-ENB-specific
subframes, and the second bitmap of the NP-ENB-specific subframes.
The subframes which do not belonging to the P-ENB-specific and
NP-ENB-specific subframes are the common subframes.
[0428] The P-ENB determines the type of a certain subframe
according to the following rule. [0429] If a subframe is DL in the
primary set serving cell and UL in the non-primary set serving
cell, this subframe is determined as a NP-ENB subframe. [0430] If a
subframe is UL in the primary set serving cell and DL in the
non-primary set serving cell, this subframe is determined as a
P-ENB subframe. [0431] Some of the subframes which are UL in both
the primary and non-primary sets serving cells are determined as
P-ENB subframes and the others as NP-ENB subframes. [0432] Some of
the subframes which are DL in both the primary and non-primary sets
serving cells are determined as P-ENB subframes and the other as
NP-eNBs.
[0433] The P-ENB sends the NP-ENB a control message of requesting
for adding SCells at step 2745. The control message is identical
with the control message of step 1845 and may further include
subframe pattern proposal information. The subframe pattern
proposal information includes a bitmap indicating P-ENB subframes,
a bitmap indicating NP-ENB subframes, and maximum transmit power
value to be used by the p-eNB at the common subframe.
[0434] The NP-ENB sends the P-ENB a SCell Add Accept control
message at step 2750. This control message is identical with the
control message of step 1850 and may further include the
information on whether to accept the frame pattern.
[0435] The P-ENB sends the UE an RRC Connection Reconfiguration
message instructing to add SCells at step 1855. The NP-ENB
schedules the UL transmission of the UE using the NP-ENB subframes
with priority and, if necessary, uses the common subframe at a
limited transmit power at step 2760. The P-ENB schedules the UL
transmission of the UE using the P-ENB subframes with priority and,
if necessary, uses the common subframes at a limited transmit power
at step 2765.
[0436] FIG. 29 is a block diagram illustrating a configuration of
the UE according to an embodiment of the present invention.
[0437] Referring to FIG. 29, the UE according to an embodiment of
the present invention includes a transceiver 2905, a controller
2910, a multiplexer/demultiplexer 2920, a control message processor
2935, and higher layer processors 2925 and 2930.
[0438] The transceiver 2905 receives data and predetermined
controls signals through the downlink channel of the serving cell
and transmits data and control signals on the uplink channel. In
the case that multiple serving cells are configured, the
transceiver 2905 performs data and control signal communication
through the multiple serving cells.
[0439] The multiplexer/demultiplexer 2915 multiplexes the data
generated by the higher layer processors 2925 and 2930 and the
control message processor 2935 and demultiplexes the data received
by the transceiver 2905, the demultiplexed data being delivered to
the higher layer processors 2925 and 2930. Although the P-ENB and
np-eNB are configured with independent multiplexer/demultiplexer
(or MAC entity), the UE is configured to have one
multiplexer/demultiplexer (or MAC entity).
[0440] The control message processor 2930 is an RRC layer entity to
process the control message received from the eNB and perform
necessary operation. For example, the control message processor
receives an RRC control message and transfers the random access
information to the controller.
[0441] The higher layer processors 2935 and 2930 are established
per service. The higher layer processor processes the data
generated in association with the user service such as File
Transfer Protocol (FTP) and Voice over Internet Protocol (VoIP) and
transfers the processed data to the multiplexer/demultiplexer 2920
or processes the data from the multiplexer/demultiplexer 2920 and
delivers the processed data to the higher layer serving
application.
[0442] The controller 2910 checks the scheduling command, e.g. UL
grants, received by the transceiver 2905 and controls the
transceiver 2905 and the multiplexer/demultiplexer 2920 to perform
UL transmission using appropriate transmission resource at an
appropriate timing. The controller controls overall operations
related to the SCell configuration. In detail, the controller
controls the UE operations as described with reference to FIGS. 5
to 28.
[0443] FIG. 30 is a block diagram illustrating a configuration of
the P-ENB according to an embodiment of the present invention.
[0444] The NP-ENB according to an embodiment of the present
invention includes a transceiver 3005, a controller 3010, a
multiplexer/demultiplexer 3020, a control message processor 3035,
higher layer processors 3025 and 3030, and a processor 3015.
[0445] The transceiver 3005 transmits data and predetermined
control signals on a DL carrier and receives data and predetermined
control signals on a UL carrier. In the case that multiple carriers
are configured, the transceiver 3005 performs the data and controls
signal communication on the multiple carriers.
[0446] The multiplexer/demultiplexer 3020 multiplexes the data
generated by the higher layer processors 3025 and 3030 and the
control message processor 3035 and demultiplexes the data received
by the transceiver 3005, the demultiplexed data being delivered to
the higher layer processors 3025 and 3030 or the controller 3010.
The control message processor 3035 processes the control message
transmitted by the UE and the control message to be transmitted to
the UE to the lower layer.
[0447] The higher layer processor 3025 and 3030 are established per
bearer and processes the data transmitted by the SGW or another eNB
into RLC PDUs which are transferred to the
multiplexer/demultiplexer 3020 or processes the RLC PDUs from the
multiplexer/demultiplexer 3020 into PDCP SDUs which are transferred
to the SGW or another eNB. The higher layer processor 3030
corresponding to whole or part of the NP-DRB is configured at the
P-ENB.
[0448] The scheduler allocates transmission resource to the UE in
consideration of the buffer status and channel condition of the UE
and controls the transceiver to process the signal transmitted by
the UE or the signal to be transmitted to the UE.
[0449] The controller controls overall operations related to SCell
configuration. In detail, the controller controls the P-ENB
operations as described with reference to FIGS. 5 to 28.
[0450] FIG. 31 is a block diagram illustrating a configuration of
the NP-ENB according to an embodiment of the present invention. The
NP-ENB according to an embodiment of the present invention includes
a transceiver 3105, a controller 3110, a multiplexer/demultiplexer
3120, a control message processor 3135, higher layer processor
3130, and a processor 3115.
[0451] The transceiver 3105 transmits data and predetermined
control signals on a DL carrier and receives data and predetermined
control signals on a UL carrier. In the case that multiple carriers
are configured, the transceiver 3105 performs the data and controls
signal communication on the multiple carriers.
[0452] The multiplexer/demultiplexer 3120 multiplexes the data
generated by the higher layer processor 3130 and the control
message processor 3135 and demultiplexes the data received by the
transceiver 3105, the demultiplexed data being delivered to the
higher layer processor 3130 or the controller 3110. The control
message processor 3135 processes the control message transmitted by
the P-ENB and takes an appropriate action.
[0453] The higher layer processor 3030 corresponding part or whole
of the NP-DRB is configured at the NP-ENB.
[0454] The scheduler allocates transmission resource to the UE in
consideration of the buffer status and channel condition of the UE
and controls the transceiver to process the signal transmitted by
the UE or the signal to be transmitted to the UE.
[0455] The controller controls overall operations related to SCell
configuration. In detail, the controller controls the NP-ENB
operations as described with reference to FIGS. 5 to 28.
* * * * *