U.S. patent application number 16/434896 was filed with the patent office on 2019-09-19 for system and method for transmit power control with secondary uplink pilot channel.
The applicant listed for this patent is Futurewei Technologies, Inc.. Invention is credited to Carmela Cozzo, Xiaolei Tie, Peng Zhang.
Application Number | 20190289558 16/434896 |
Document ID | / |
Family ID | 55162519 |
Filed Date | 2019-09-19 |
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United States Patent
Application |
20190289558 |
Kind Code |
A1 |
Cozzo; Carmela ; et
al. |
September 19, 2019 |
System and Method for Transmit Power Control with Secondary Uplink
Pilot Channel
Abstract
A method for operating a user equipment (UE) configured for
estimating channel quality includes receiving a downlink fractional
control channel from a non-serving HS-DSCH cell, estimating a
quality of the downlink fractional control channel over a specified
time period, and deriving downlink synchronization primitives in
accordance with the quality of the downlink fractional control
channel. Further methods for deriving the transmit power of an
uplink control channel from downlink fractional control channels
transmitted by the serving and non-serving HS-DSCH cells are
disclosed.
Inventors: |
Cozzo; Carmela; (San Diego,
CA) ; Zhang; Peng; (Shenzhen, CN) ; Tie;
Xiaolei; (Shanghai, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Futurewei Technologies, Inc. |
Plano |
TX |
US |
|
|
Family ID: |
55162519 |
Appl. No.: |
16/434896 |
Filed: |
June 7, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15877079 |
Jan 22, 2018 |
10321413 |
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16434896 |
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14803874 |
Jul 20, 2015 |
9877288 |
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15877079 |
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62029268 |
Jul 25, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/325 20130101;
H04W 52/146 20130101; H04W 52/16 20130101; H04W 52/248 20130101;
H04L 5/0048 20130101; H04W 88/08 20130101; H04W 74/002 20130101;
H04L 25/0202 20130101; H04W 52/40 20130101; H04W 52/244 20130101;
H04W 56/00 20130101; H04W 52/247 20130101; H04W 88/02 20130101 |
International
Class: |
H04W 52/24 20060101
H04W052/24; H04W 52/40 20060101 H04W052/40; H04W 52/32 20060101
H04W052/32; H04W 52/14 20060101 H04W052/14; H04L 25/02 20060101
H04L025/02; H04W 74/00 20060101 H04W074/00; H04W 52/16 20060101
H04W052/16; H04L 5/00 20060101 H04L005/00; H04W 56/00 20060101
H04W056/00 |
Claims
1. A method for operating a user equipment (UE) configured for
estimating channel quality, the method comprising: receiving, by
the UE, a downlink fractional control channel; and reporting, by
the UE, a signal that indicates downlink synchronization primitives
derived in accordance with a quality of the downlink fractional
control channel over a time period.
2. The method of claim 1, wherein the signal that indicates the
downlink synchronization primitives is a higher layer signal.
3. The method of claim 1, the downlink fractional control channel
is a fractional dedicated physical channel (F-DPCH.sub.NON-SERVING)
and an uplink physical control channel comprises a secondary
dedicated physical control channel (DPCCH2).
4. The method of claim 1, the downlink synchronization primitives
include a CPHY-Sync-IND.
5. The method of claim 1, the downlink synchronization primitives
include a CPHY-Out-of-Sync-IND.
6. The method of claim 1, wherein the downlink fractional control
channel is received from one of a high-speed downlink shared
channel (HS-DSCH) cell and an enhanced dedicated channel (E-DCH)
cell when E-DCH decoupling is configured.
7. The method of claim 1, wherein the downlink synchronization
primitives are derived from a quality of transmit power control
(TPC) fields in the downlink fractional control channel.
8. A user equipment (UE) comprising: a processor; and a
non-transitory computer readable storage medium storing programming
for execution by the processor, the programming including
instructions to: receive a downlink fractional control channel; and
report a signal that indicates downlink synchronization primitives
derived in accordance with a quality of the downlink fractional
control channel over a time period.
9. The UE of claim 8, wherein the signal that indicates the
downlink synchronization primitives is a higher layer signal.
10. The UE of claim 8, the downlink fractional control channel is a
fractional dedicated physical channel (F-DPCH.sub.NON-SERVING) and
an uplink physical control channel comprises a secondary dedicated
physical control channel (DPCCH2).
11. The UE of claim 8, the downlink synchronization primitives
include a CPHY-Sync-IND.
12. The UE of claim 8, the downlink synchronization primitives
include a CPHY-Out-of-Sync-IND.
13. The UE of claim 8, wherein the downlink fractional control
channel is received from one of a high-speed downlink shared
channel (HS-DSCH) cell and an enhanced dedicated channel (E-DCH)
cell when E-DCH decoupling is configured.
14. The UE of claim 8, wherein the downlink synchronization
primitives are derived from a quality of transmit power control
(TPC) fields in the downlink fractional control channel.
15. A computer program product comprising a non-transitory computer
readable storage medium storing programming, the programming
including instructions to: receive, by a user equipment (UE), a
downlink fractional control channel; and report, by the UE, a
signal that indicates downlink synchronization primitives derived
in accordance with a quality of the downlink fractional control
channel over a time period.
16. The computer program product of claim 15, the downlink
fractional control channel is a fractional dedicated physical
channel (F-DPCH.sub.NON-SERVING) and an uplink physical control
channel comprises a secondary dedicated physical control channel
(DPCCH2).
17. The computer program product of claim 15, the downlink
synchronization primitives include a CPHY-Sync-IND.
18. The computer program product of claim 15, the downlink
synchronization primitives include a CPHY-Out-of-Sync-IND.
19. The computer program product of claim 15, wherein the downlink
fractional control channel is received from one of a high-speed
downlink shared channel (HS-DSCH) cell and an enhanced dedicated
channel (E-DCH) cell when E-DCH decoupling is configured.
20. The computer program product of claim 15, wherein the downlink
synchronization primitives are derived from a quality of transmit
power control (TPC) fields in the downlink fractional control
channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/877,079, filed on Jan. 22, 2018, entitled
"System and Method for Transmit Power Control with Secondary Uplink
Pilot Channel," which is a continuation of U.S. patent application
Ser. No. 14/803,874, filed on Jul. 20, 2015, (now U.S. Pat. No.
9,877,288 issued Jan. 23, 2018), entitled "System and Method for
Transmit Power Control with Secondary Uplink Pilot Channel," which
claims the benefit of U.S. Provisional Application No. 62/029,268,
filed on Jul. 25, 2014, entitled "System and Method for Transmit
Power Control with Secondary Uplink Pilot Channel," all of which
applications are hereby incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to digital
communications, and more particularly to a system and method for
transmit power control with secondary uplink pilot channel.
BACKGROUND
[0003] The deployment of heterogeneous networks (Hetnets), which
are mixed deployments of high power NodeBs (macro node) and low
power nodes (LPNs), aims at increasing network capacity and
coverage. The difference in transmit power between the macro node
and the LPN causes different coverage areas for the UL and the
DL.
[0004] Considering a soft handover region between a macro and an
LPN, the macro node, being the more dominant node, is more likely
to be the serving node. However, the signal received at the LPN can
be much stronger than the signal received at the macro node.
Considering the received signal to noise ratio (SNR) of the pilot
channel in the uplink (UL), since both the macro node and the LPN
can control the transmit power level of the user equipment (UE),
the transmit power of the UE is largely driven by the LPN. As a
consequence, the high speed-dedicated physical control channel
(HS-DPCCH) that carries the hybrid automatic repeat request
acknowledgement (HARQ-ACK) and channel quality indicator (CQI) may
not be reliably decoded at the serving macro node. In this
scenario, unreliable HARQ-ACK decoding, especially high ACK to
discontinuous transmission (DTX) error, causes unnecessary
retransmissions and degrades the downlink (DL) throughput
performance.
SUMMARY
[0005] Example embodiments provide a system and method for transmit
power control with secondary uplink pilot channel.
[0006] In accordance with an example embodiment, a method is
provided for operating a user equipment (UE) configured for
estimating channel quality. The method includes receiving, by the
UE, a downlink fractional control channel from a non-serving cell,
estimating, by the UE, a quality of the downlink fractional control
channel over a specified time period, and deriving, by the UE,
downlink synchronization primitives in accordance with the quality
of the downlink fractional control channel.
[0007] In accordance with another example embodiment, a method is
provided for operating a user equipment (UE) configured for
performing transmit power control (TPC). The method includes
receiving, by the UE, a first downlink fractional control channel
from a serving high-speed downlink shared channel (HS-DSCH) cell
and a downlink fractional control channel from a non-serving
HS-DSCH cell, and determining, by the UE, a transmit power of an
uplink dedicated physical control channel (DPCCH) in accordance
with TPC fields in the downlink fractional control channel from the
non-serving HS-DSCH cell.
[0008] In accordance with an example embodiment, a method is
provided for operating a user equipment (UE) configured for
performing transmit power control (TPC). The method includes
determining, by the UE, a transmit power of an uplink dedicated
physical control channel (DPCCH) in accordance with a first
combination of TPC fields from at least one of a first downlink
fractional control channel from a serving high-speed downlink
shared channel (HS-DSCH) cell, a second downlink fractional control
channel from the serving HS-DSCH cell, and a downlink fractional
control channel from a non-serving HS-DSCH cell, receiving, by the
UE, signaling indicating a switch in how the transmit power of the
DPCCH is determined, and determining, by the UE, the transmit power
of the DPCCH in accordance with a second combination of the TPC
fields from at least one of the first downlink fractional control
channel from the serving HS-DSCH cell, the second downlink
fractional control channel from the serving HS-DSCH cell, and the
downlink fractional control channel from the non-serving HS-DSCH
cell.
[0009] In accordance with an example embodiment, a user equipment
(UE) is provided to estimate channel quality. The UE includes a
processor, and a computer readable storage medium coupled to the
processor and storing programming for execution by the processor.
The programming includes instructions configuring the UE to receive
a downlink fractional control channel from a non-serving cell,
estimate a quality of the downlink fractional control channel over
a specified time period, and derive downlink synchronization
primitives in accordance with the quality of the downlink
fractional control channel.
[0010] In accordance with an example embodiment, a user equipment
(UE) is provided to perform transmit power control (TPC). The UE
includes a processor, and a computer readable coupled to the
processor and storage medium storing programming for execution by
the processor. The programming includes instructions configuring
the UE to receive a first downlink fractional control channel from
a serving high-speed downlink shared channel (HS-DSCH) cell and a
downlink fractional control channel from a non-serving HS-DSCH
cell, and determine a transmit power of an uplink dedicated
physical control channel (DPCCH) in accordance with TPC fields in
the downlink fractional control channel from the non-serving
HS-DSCH cell.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the present disclosure,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawing, in
which:
[0012] FIG. 1 illustrates an example communications system
according to example embodiments described herein;
[0013] FIG. 2 illustrates a message exchange diagram highlighting
power control relationships between control channels according to
example embodiments described herein;
[0014] FIG. 3A illustrates a communications system highlighting
control signals present in a situation wherein the DPCCH2 is
transmitted continuously according to example embodiments described
herein;
[0015] FIG. 3B illustrates a message exchange diagram occurring in
a situation wherein the DPCCH2 is transmitted continuously
according to example embodiments described herein;
[0016] FIG. 4A illustrates a communications system highlighting
control signals present in a situation as described by the third
example embodiment according to example embodiments described
herein;
[0017] FIG. 4B illustrates a message exchange diagram occurring in
a situation as described by the third example embodiment according
to example embodiments described herein;
[0018] FIG. 5A illustrates a communications system highlighting
control signals present in a situation as described by the fifth
example embodiment according to example embodiments described
herein;
[0019] FIG. 5B illustrates a message exchange diagram occurring in
a situation as described by the fifth example embodiment according
to example embodiments described herein;
[0020] FIG. 6 illustrates a flow diagram of example operations
occurring in a UE deriving downlink synchronization primitives
according to example embodiments described herein;
[0021] FIG. 7 illustrates a flow diagram of example operations
occurring in a UE performing power control for a DPCCH according to
example embodiments described herein; and
[0022] FIG. 8 is a block diagram of a processing system that may be
used for implementing the devices and methods disclosed herein.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0023] The operating of the current example embodiments and the
structure thereof are discussed in detail below. It should be
appreciated, however, that the present disclosure provides many
applicable inventive concepts that can be embodied in a wide
variety of specific contexts. The specific embodiments discussed
are merely illustrative of specific structures of the disclosure
and ways to operate the embodiments disclosed herein, and do not
limit the scope of the disclosure.
[0024] One embodiment relates to transmit power control with
secondary uplink pilot channel. For example, a UE receives a
downlink fractional control channel transmitted by a non-serving
cell, estimates a quality of the downlink fractional control
channel over a specified time period, and derives downlink
synchronization primitives in accordance with the estimated quality
of the downlink fractional control channel.
[0025] The embodiments will be described with respect to example
embodiments in a specific context, namely communications systems
that perform transmit power control with a secondary uplink pilot
channel. The embodiments may be applied to standards compliant
communications systems, such as those that are compliant with Third
Generation Partnership Project (3GPP), Universal Mobile
Telecommunications System (UMTS), IEEE 802.11, and the like,
technical standards, and non-standards compliant communications
systems, that perform transmit power control with a secondary
uplink pilot channel.
[0026] FIG. 1 illustrates an example communications system loft
Communications system 100 includes a UE 105, a macro node 110, and
a plurality of LPNs, such as LPN 115 and LPN 117. In general, a
macro node may also be referred to as a base station, a NodeB, an
evolved NodeB (eNB), a communications controller, a base terminal
station, an access point, a high power node, and so on. Similarly,
an LPN may be referred to as a pico cell, a femto cell, a remote
radio head (RRH), and so forth, while a UE may be referred to as a
mobile station, a mobile, a terminal, a subscriber, a user,
etc.
[0027] While it is understood that communications systems may
employ multiple nodes capable of communicating with a number of
UEs, only one macro node, two LPNs, and one UE are illustrated for
simplicity.
[0028] Also shown in FIG. 1 are control channels exchanged between
UE 105, macro node 110, and LPNs 115 and 117. The control channels
may include a secondary dedicated physical control channel 2
(DPCCH2) 150 in the UL that serves as a phase reference to assist
in estimating a communications channel for demodulating a high
speed-downlink shared channel (HS-DPCCH) 152. DPCCH2 150 is power
controlled by macro node 110. A primary pilot channel (DPCCH) 154
in the UL serves as a phase reference to assist in the demodulation
of an enhanced DPCCH (E-DPCCH) and enhanced-dedicated physical data
channels (E-DPDCHs). The decoding performance of UL data is not
affected by the introduction of DPCCH2 150. DPCCH2 150 carries
pilot symbols and transmit power control (TPC) symbols.
[0029] The transmit power of DPCCH 154 is controlled by the TPC
commands sent by a serving HS-downlink shared channel (HS-DSCH)
cell (which is shown in FIG. 1 as macro node 110) as well as
non-serving HS-DSCH cells (which are shown in FIG. 1 as LPNs 115
and 117). A non-serving HS-DSCH cell is also referred to as a
serving enhanced dedicated channel (E-DCH) cell when E-DCH
decoupling is operating.
[0030] The TPC commands from the HS-DSCH cell are carried on a
fractional dedicated physical channel 1 (F-DPCH1) 156 and TPC
commands from a non-serving HS-DSCH cell are carried on
F-DPCH.sub.NON-SERVING 158. When there are multiple non-serving
HS-DSCH cells, as is shown in FIG. 1, there are multiple
F-DPCH.sub.NON-SERVING 158 and the TPC commands carried by each
F-DPCH.sub.NON_SERVING 158 are independent.
[0031] The transmit power of DPCCH2 150 is controlled by the TPC
commands sent by the serving HS-DSCH cell. The TPC commands from
the HS-DSCH cell are carried on F-DPCH2 160. Both F-DPCH1 156 and
F-DPCH2 160 are sent from the serving HS-DSCH cell and
non-colliding resources are used for F-DPCH1 156 and F-DPCH2 160.
DPCCH2 150 carries the TPC commands for F-DPCH1 156 and F-DPCH2
160. DPCCH 154 carries the TPC commands for at least one of
multiple F-DPCH.sub.NON-SERVING 158 transmitted by non-serving
HS-DSCHs.
[0032] FIG. 2 illustrates a message exchange diagram 200
highlighting power control relationships between control channels.
Message exchange diagram 200 displays control channels exchanged
between a UE 205, a macro node 210, and a LPN 215. A DPCCH2 250 is
used to provide a phase reference for demodulating a HS-DPCCH 252.
DPCCH2 250 includes TPC commands for a F-DPCH1 256 and a F-DPCH2
260. F-DPCH1 256 includes TPC commands for a DPCCH 254. DPCCH 254
includes TPC commands for a F-DPCH.sub.NON-SERVING 258. F-DPCH1 256
includes TPC commands for DPCCH 254, while F-DPCH2 260 carries TPC
commands for DPCCH2 250.
[0033] A HS-DPCCH consists of a 2-slot channel quality indicator
(CQI) and/or precoding control indicator (PCI) field and a 1-slot
hybrid automatic repeat requested (HARQ)-acknowledgement (ACK)
field. The HARQ-ACK field carries a positive and/or negative
acknowledgement (ACK and/or NACK) response for the HS-PDSCH data
received at a UE. It is only transmitted after the UE receives the
HS-PDSCH data. The CQI and/or PCI field carries the CQI and/or PCI
for the downlink channel. The HS-DPCCH is transmitted with a
certain transmission cycle that is specified by the communications
system or an operator thereof.
[0034] During every radio frame (a basic structure for transmitted
information in a wireless communications system), UEs check the
synchronization status of the F-DPCH1. The synchronization status
is indicated to higher layers using CPHY-Sync-IND and
CPHY-Out-of-Sync-IND primitives to represent in-sync and
out-of-sync status, respectively.
[0035] There are several possible criteria for reporting
synchronization status. In a first criterion, an in-sync status is
reported using the CPHY-Sync-IND primitive if a UE estimates the
quality of the TPC fields of the F-DPCH1 frame received from an
associated serving HS-DSCH cell over a specified time period is
better than a threshold Qin. In a second criterion, both an in-sync
status and an out-of-sync status may be reported. The in-sync
status is reported as described for the first criterion, while the
out-of-sync status is reported using the CPHY-Out-of-Sync-IND
primitive if a UE estimates the quality of the TPC fields of the
F-DPCH1 frame received from an associated serving HS-DSCH cell over
a specified time period is worse than a threshold Qout.
[0036] FIG. 3A illustrates a communications system 300 highlighting
control signals present in a situation wherein the DPCCH2 is
transmitted continuously. Communications system 300 includes a UE
305, a macro node 310, and a LPN 315. As shown in FIG. 3A, macro
node 310 is operating as a serving HS-DSCH cell for UE 305 and LPN
315 is operating as a non-serving HS-DSCH cell for UE 305. Control
channels include: DPCCH2 325, F-DPCH2 327, F-DPCH1 329, DPCCH 331,
and F-DPCH.sub.NON-SERVING 333.
[0037] FIG. 3B illustrates a message exchange diagram 350 occurring
in a situation wherein the DPCCH2 is transmitted continuously.
Message exchange diagram 350 displays control channels exchanged
between UE 305, macro node 310, and LPN 315.
[0038] Generally, the HS-DPCCH transmission is continuous (the
HS-DPCCH is transmitted in every transmission time interval (TTI))
and that the DPCCH2 transmission is also continuous. In such a
situation, control channels are exchanged between UE 305, macro
node 310, and LPN 315 may include a F-DPCH2 (shown as event 355), a
DPCCH2 (shown as event 360), a F-DPCH1 (shown as event 365), a
F-DPCH.sub.NON-SERVING (shown as event 370), and a DPCCH (shown as
event 375).
[0039] A summary of the behavior of macro node 310 (operating as
the serving HS-DSCH cell) and UE 305 is as follows:
[0040] Macro node 310 transmits F-DPCH1 and F-DPCH2;
[0041] UE 305 determines the uplink transmit power of DPCCH2
according to the TPC command carried on F-DPCH2 from macro node 310
(serving HS-DSCH cell). UE 305 also determines the uplink transmit
power of DPCCH according to a combination of the TPC commands
carried on F-DPCH1 from macro node 310 (serving HS-DSCH cell) and
F-DPCH.sub.NON-SERVING from LPN 315 (non-serving HS-DSCH cell). UE
305 includes TPC commands in messages 360 (DPCCH2) and 375
(DPCCH).
[0042] However, when CQI and/or PCI reporting is configured with a
long transmission cycle and a UE does not receive the HS-PDSCH for
an extended amount of time, the UE stops transmitting the HS-DPCCH
for a number of TTI. Therefore, the DPCCH2 is also not transmitted.
Absence of the DPCCH2 may lead to several complications,
including:
[0043] The quality of the F-DPCH1 that is transmitted by the
serving HS-DSCH cell becomes unreliable since the TPC commands
ordinarily carried by the DPCCH2 are no longer available for the
serving HS-DSCH cell during downlink transmission gaps. The
unreliable F-DPCH1 quality may cause the UE to report out-of-sync
status.
[0044] The power control for the DPCCH becomes unreliable since the
power of the DPCCH is controlled according to a combination of the
F-DPCH1 from the serving HS-DSCH cell and the
F-DPCH.sub.NON-SERVING from at least one of the non-serving HS-DSCH
cells. Since F-DPCH1 is unreliable due to the absence of the TPC
commands carried on the DPCCH2, the combination of the F-DPCH1 and
the F-DPCH.sub.NON-SERVING is also unreliable.
[0045] According to example embodiments, systems and methods are
presented that solve the issues of the unreliable quality of the
F-DPCH1 transmitted by a serving HS-DSCH cell and unreliable power
control for the DPCCH when the DPCCH2 is not transmitted. The
example embodiments may be implemented in heterogeneous or
homogeneous communications systems, such as Universal Mobile
Telecommunications System (UMTS), 3GPP LTE, IEEE 802.11, and so on,
communications systems and devices, such as eNBs, NodeBs, base
stations, LPNs, UEs, etc.
[0046] A UE may estimate the quality of the TPC fields of the
F-DPCH1 over a specified number of slots in which the TPC symbols
are known to be present in order to potentially avoid reporting the
CPHY-Out-of-Sync-IND primitive. When the DPCCH2 is transmitted, the
F-DPCH1 is transmitted by the serving HS-DSCH cell and the UE knows
when the TPC symbols are present. When the DPCCH2 is not
transmitted, the UE will not attempt to estimate the F-DPCH1
quality (the quality of the TPC symbols) to derive the
synchronization primitives. By doing so, unnecessary out-of-sync
reporting may be prevented. However, the above discussed problem
regarding the unreliability of power control for the DPCCH is not
resolved.
[0047] According to an example embodiment, uplink power control and
downlink synchronization in the presence of a secondary uplink
pilot channel, e.g., in UMTS communications systems, are presented.
The transmission pattern of the secondary uplink pilot channel
impacts the uplink power control loop and the transmission of the
downlink channels that carry TPC commands.
[0048] Under the assumption that a DPCCH2 is not transmitted
continuously, for example, the DPCCH2 is transmitted only when a
HS-DPCCH is transmitted, during a period when DPCCH2 is not
transmitted, a UE knows that TPC commands from the serving HS-DSCH
cell may be unreliable. Therefore, the UE ignores the TPC commands
included in the F-DPCH1 and F-DPCH2 transmitted by the serving
HS-DSCH cell in downlink slots associated with uplink slots in
which the DPCCH2 is not transmitted. The UE combines received TPC
commands from at least one non-serving HS-DSCH cell (i.e., the
serving E-DCH cell) to control the power of the DPCCH.
[0049] If the TPC commands from the serving HS-DSCH cell are known
to be unreliable (such as when the DPCCH2 is not transmitted) the
serving HS-DSCH cell may stop the transmission of the F-DPCH1 and
F-DPCH2 to save transmission power at the serving HS-DSCH cell. The
UE combines received TPC commands from at least one non-serving
HS-DSCH cell to control the power of the DPCCH.
[0050] According to a first example embodiment, in a situation
where the DPCCH2 is only transmitted together with the HS-DPCCH,
when the DPCCH2 is not transmitted, the F-DPCH1 and F-DPCH2 from
the serving HS-DSCH cell would be unreliable, therefore the serving
HS-DSCH cell and UE behaves as follows:
[0051] Serving HS-DSCH cell: [0052] F-DPCH1 is transmitted by the
serving HS-DSCH cell; and F-DPCH2 is transmitted by the serving
HS-DSCH cell or F-DPCH2 is NOT transmitted by the serving HS-DSCH
cell; and
[0053] UE: [0054] The UE assumes that for a period of time the
quality of the TPC commands on F-DPCH1 is unreliable; and the UE
only uses the TPC commands received from the non-serving HS-DSCH
cells for TPC combining to control the power of the DPCCH; and
[0055] Alternatively, the UE assumes the TPC commands on the
F-DPCH1 are always +1 and uses them together with the TPC commands
received from the non-serving HS-DSCH cells for TPC combining to
control the power of the DPCCH.
[0056] According to a second example embodiment, in a situation
where the DPCCH2 is only transmitted together with the HS-DPCCH,
when the DPCCH2 is not transmitted, the F-DPCH1 and F-DPCH2 from
the serving HS-DSCH cell would be unreliable, therefore the serving
HS-DSCH cell and UE behave as follows:
[0057] Serving HS-DSCH cell: [0058] F-DPCH1 is NOT transmitted by
the serving HS-DSCH cell in downlink slots associated with uplink
slots in which HS-DPCCH or DPCCH2 is not transmitted; and [0059]
F-DPCH2 is transmitted by serving HS-DSCH cell or F-DPCH2 is NOT
transmitted by the serving HS-DSCH cell; and
[0060] UE: [0061] The UE assumes that for a period of time the
quality of the TPC commands on F-DPCH1 is unreliable; and the UE
only uses the TPC commands received from the non-serving HS-DSCH
cells for TPC combining to control the power of the DPCCH.
[0062] According to a third example embodiment, in a situation when
the DPCCH2 is only transmitted with the HS-DPCCH, the serving
HS-DSCH cell and UE behaves as follows:
[0063] Serving HS-DSCH cell: [0064] F-DPCH1 is not transmitted;
and
[0065] UE: [0066] The UE determines the uplink transmit power of
the DPCCH2 according to the TPC command conveyed by the F-DPCH2
transmitted by the serving HS-DSCH cell; and [0067] The UE
determines the uplink transmit power of the DPCCH according to the
TPC command conveyed by the F-DPCH.sub.NON-SERVING transmitted by
at least one non-serving HS-DSCH cell.
[0068] FIG. 4A illustrates a communications system 400 highlighting
control signals present in a situation as described by the third
example embodiment. Communications system 400 includes a UE 405, a
macro node 410, and a LPN 415. As shown in FIG. 4A, macro node 410
is operating as a serving HS-DSCH cell for UE 405 and LPN 415 is
operating as a non-serving HS-DSCH cell for UE 405. Control
channels include: DPCCH2 420, F-DPCH2 422, DPCCH 424 from UE 405 to
LPN 415, and F-DPCH.sub.NON-SERVING 426. Control channels DPCCH 428
from UE 405 to macro node 410 and F-DPCH1 430 are not present. FIG.
4B illustrates a message exchange diagram 450 occurring in a
situation as described by the third example embodiment. Message
exchange diagram 450 displays control channels exchanged between UE
405, macro node 410, and LPN 415. Control channels exchanged
between UE 405, macro node 410, and LPN 415 may include a F-DPCH2
(shown as event 455), a DPCCH2 (shown as event 460), a
F-DPCH.sub.NON-SERVING (shown as event 470) and a DPCCH between UE
405 and LPN 415 (shown as event 475). Control channel F-DPCH1 is
absent (shown as crossed out event 465).
[0069] According to a fourth example embodiment, in a situation
when the DPCCH2 is only transmitted with the HS-DPCCH, the serving
HS-DSCH cell and the UE behaves as follows:
[0070] Serving HS-DSCH cell: [0071] F-DPCH1 is transmitted when
F-DPCH2 is transmitted. The TPC commands conveyed by F-DPCH1 are
identical to the TPC commands conveyed by F-DPCH2; and
[0072] UE: [0073] The UE determines the uplink transmit power of
DPCCH2 according to the TPC commands conveyed by F-DPCH1 and/or
F-DPCH2 from the serving HS-DSCH cell, e.g., through a soft
combining of the received TPC commands from F-DPCH1 and/or F-DPCH2;
and [0074] The UE determines the uplink transmit power of DPCCH
according to the TPC commands conveyed by F-DPCH.sub.NON-SERVING
from the at least one non-serving HS-DSCH cell.
[0075] According to a fifth example embodiment, in a situation when
the DPCCH2 is transmitted only with the HS-PDCCH, the serving
HS-DSCH cell and the UE behaves as follows:
[0076] Serving HS-DSCH cell: [0077] F-DPCH1 is power controlled by
the TPC conveyed by the DPCCH; [0078] F-DPCH2 is power controlled
by the TPC conveyed on the DPCCH2; and
[0079] UE: [0080] The UE determines the uplink transmit power of
DPCCH2 according to the TPC commands conveyed by F-DPCH2 from the
serving HS-DSCH cell; [0081] The UE determines the uplink transmit
power of DPCCH according to a combination of the TPC commands
conveyed by F-DPCH1 from serving HS-DSCH cell and
F-DPCH.sub.NON-SERVING from non-serving HS-DSCH cell; and [0082]
For the TPC commands conveyed by PDCCH in the uplink, the UE
considers both the F-DPCH.sub.NON-SERVING from non-serving HS-DSCH
cell and F-DPCH1 from serving HS-DSCH cell, meaning that the TPC
commands on the DPCCH should guarantee both the reliability of
F-DPCH1 and F-DPCH.sub.NON-SERVING. By doing this, the reliability
of F-DPCH1 generally can be guaranteed even though the DPCCH2 is
not transmitted. The DPCCH2 power control loop and DPCCH power
control loop are isolated from each other.
[0083] FIG. 5A illustrates a communications system 500 highlighting
control signals present in a situation as described by the fifth
example embodiment. Communications system 500 includes a UE 505, a
macro node 510, and a LPN 515. As shown in FIG. 5A, macro node 510
is operating as a serving HS-DSCH cell for UE 505 and LPN 515 is
operating as a non-serving HS-DSCH cell for UE 505. Control
channels include: DPCCH2 520, F-DPCH2 522, F-DPCH1 526, DPCCH 524,
and F-DPCH.sub.NON-SERVING 528. FIG. 5B illustrates a message
exchange diagram 550 occurring in a situation as described by the
fifth example embodiment. Message exchange diagram 550 displays
control channels exchanged between UE 505, macro node 510, and LPN
515. Control channels exchanged between UE 505, macro node 510, and
LPN 515 may include a F-DPCH2 (shown as event 555), a DPCCH2 (shown
as event 560), a F-DPCH1 (shown as event 565), a
F-DPCH.sub.NON-SERVING (shown as event 570) and a DPCCH between UE
505 and LPN 515 (shown as event 575).
[0084] According to a sixth example embodiment, a plurality of
possible configurations for the transmission of the F-DPCH1 by the
serving HS-DSCH cell and the combining of the TPC commands by the
UE are specified and the serving HS-DSCH cell and the UE are able
to switch between different configurations. Examples of possible
configurations include those disclosed in the first through fifth
example embodiments.
[0085] The switching between different configurations may be
explicitly triggered or implicitly triggered. As an illustrative
example, in explicit triggering of configuration switching, higher
layer signaling (such as radio resource control (RRC) signaling,
for example) is sent from the communications system to the UE to
instruct the UE to switch to a different configuration.
Alternatively, physical (PHY) layer signaling (e.g., a HS-shared
control channel (HS-SCCH) order) may be sent from the
communications system to the UE to instruct the UE to switch to a
different configuration. As an illustrative example, in implicit
triggering of configuration switching, at least one parameter may
be determined as a threshold to trigger the configuration
switching. For example, the length of the CQI cycle is set as the
metric, and if the length of the CQI cycle is greater than a
specified threshold, the UE switches to a different configuration.
The specified threshold may be signaled by the network using higher
layer signaling, PHY layer signaling, or it may be predetermined by
the communications system and the UE.
[0086] According to a seventh example embodiment, in a situation
where the DPCCH2 is not continuously transmitted and the F-DPCH1 is
always transmitted by serving HS-DSCH cell, the UE behaves as
follows:
[0087] In a first option, the UE derives the downlink
synchronization primitives from the estimated quality of F-DPCH1
from the serving HS-DSCH cell over a previous certain number of
slots in which F-DPCH1 transmission is associated with DPCCH2
transmission. The UE derives the downlink synchronization
primitives from the estimated quality of the F-DPCH1 from the
serving HS-DSCH cell over the previous certain number of slots and
DPCCH2 is not transmitted.
[0088] In a second option, the UE derives the downlink
synchronization primitives from the estimated quality of F-DPCH1
from the serving HS-DSCH cell and F-DPCH.sub.NON-SERVING from the
non-serving HS-DSCH cell over the previous certain number of slots
in which F-DPCH1 transmission is associated with DPCCH2
transmission. The UE derives the downlink synchronization
primitives from the estimated quality of F-DPCH1 from the serving
HS-DSCH cell and F-DPCH.sub.NON-SERVING from the non-serving
HS-DSCH cell over the previous certain number of slots and DPCCH2
is not transmitted.
[0089] In a third option, the UE derives the downlink
synchronization primitives from the estimated quality of
F-DPCH.sub.NON-SERVING from the non-serving HS-DSCH cell over the
previous certain number of slots in which F-DPCH1 transmission is
associated with DPCCH2 transmission. The UE derives the downlink
synchronization primitives from the estimated quality of F-DPCH1
from the non-serving HS-DSCH cell over the previous certain number
of slots and DPCCH2 is not transmitted.
[0090] According to an eighth example embodiment, in a situation
where the DPCCH2 is not continuously transmitted and the F-DPCH1 is
only transmitted when an associated DPCCH2 is transmitted, the UE
behaves as follows:
[0091] In a first option, the UE derives the downlink
synchronization primitives from the estimated quality of F-DPCH1
from the serving HS-DSCH cell over a certain number of slots in
which the F-DPCH1 is known to be present.
[0092] In a second option, the UE derives the downlink
synchronization primitives from the estimated quality of F-DPCH1
from the serving HS-DSCH cell and F-DPCH.sub.NON-SERVING from the
non-serving HS-DSCH cell over a certain number of slots in which
the F-DPCH1 is known to be present.
[0093] In a third option, the UE derives the downlink
synchronization primitives from the estimated quality of
F-DPCH.sub.NON-SERVING from the non-serving HS-DSCH cell over a
certain number of slots in which the F-DPCH1 is known to be
present.
[0094] FIG. 6 illustrates a flow diagram of example operations 600
occurring in a UE deriving downlink synchronization primitives.
Operations 600 may be indicative of operations occurring in a UE
served by a serving HS-DSCH cell and a non-serving HS-DSCH cell as
the UE derives downlink synchronization primitives in a situation
where the DPCCH2 is not transmitted.
[0095] Operations 600 may begin with the UE performing a check to
determine if the DPCCH2 is being transmitted (block 605). If the
DPCCH2 is not being transmitted, the UE receives the
F-DPCH.sub.NON-SERVING transmitted by the non-serving HS-DSCH cell
(block 610). The UE derives the downlink synchronization primitives
from the quality (estimated quality) of the F-DPCH.sub.NON-SERVING
transmitted by the non-serving HS-DSCH cell over a certain number
of slots (block 615). The number of slots over which the UE uses to
derive the downlink synchronization primitives may be specified by
a technical standard or an operator of the communications system.
The UE may also use the quality of the F-DPCH1 transmitted by the
serving HS-DSCH cell over the certain number of slots to derive the
downlink synchronization primitives. If there are a plurality of
non-serving HS-DSCH cells, the UE may use the quality of a subset
of all of F-DPCH.sub.NON-SERVING transmitted by the plurality of
non-serving HS-DSCH cells over the certain number of slots to
derive the downlink synchronization primitives.
[0096] In block 605, if the DPCCH2 is being transmitted, blocks 610
and 615 are bypassed. Instead, the UE may use the TPC fields of the
F-DPCH1 to derive the downlink synchronization primitives.
[0097] FIG. 7 illustrates a flow diagram of example operations 700
occurring in a UE performing power control for a DPCCH. Operations
700 may be indicative of operations occurring in a UE served by a
serving HS-DSCH cell and a non-serving HS-DSCH cell as the UE
performs power control for a DPCCH.
[0098] Operations 700 may begin with the UE performing a check to
determine if the DPCCH2 is being transmitted (block 705). If the
DPCCH2 is not being transmitted, the UE receives TPC commands
transmitted by at least one non-serving HS-DSCH cell (block 710).
The UE performs power control using received TPC commands
transmitted by the at least one non-serving HS-DSCH cell (block
715). The UE may also set any TPC commands transmitted by the
serving HS-DSCH cell to a specified value, such as +1, and combine
them with TPC commands transmitted by the at least one non-serving
HS-DSCH cell to perform power control. The UE may use TPC commands
transmitted by the serving HS-DSCH cell on an alternate fractional
control channel to perform power control. The UE may use TPC
commands from a plurality of fractional control channels
transmitted by the serving HS-DSCH cell to perform power control.
The UE may use TPC commands from a fractional control channel
transmitted by the serving HS-DSCH cell and a control channel
transmitted by the non-serving HS-DSCH cell (potentially more than
one) to perform power control. The way in which the UE performs
power control may be changed through an explicit trigger or an
implicit trigger.
[0099] In block 705, if the DPCCH2 is being transmitted, blocks 710
and 715 are bypassed. Instead, the UE may use the TPC commands of
the F-DPCH1 to perform power control.
[0100] FIG. 8 is a block diagram of a processing system 800 that
may be used for implementing the devices and methods disclosed
herein. In some embodiments, the processing system 800 comprises a
UE. Specific devices may utilize all of the components shown, or
only a subset of the components, and levels of integration may vary
from device to device. Furthermore, a device may contain multiple
instances of a component, such as multiple processing units,
processors, memories, transmitters, receivers, etc. The processing
system may comprise a processing unit 805 equipped with one or more
input/output devices, such as a human interface 815 (including
speaker, microphone, mouse, touchscreen, keypad, keyboard, printer,
and the like), display 810, and so on. The processing unit may
include a central processing unit (CPU) 820, memory 825, a mass
storage device 830, a video adapter 835, and an I/O interface 840
connected to a bus 845.
[0101] The bus 845 may be one or more of any type of several bus
architectures including a memory bus or memory controller, a
peripheral bus, video bus, or the like. The CPU 820 may comprise
any type of electronic data processor. The memory 825 may comprise
any type of system memory such as static random access memory
(SRAM), dynamic random access memory (DRAM), synchronous DRAM
(SDRAM), read-only memory (ROM), a combination thereof, or the
like. In an embodiment, the memory 825 may include ROM for use at
boot-up, and DRAM for program and data storage for use while
executing programs.
[0102] The mass storage device 830 may comprise any type of storage
device configured to store data, programs, and other information
and to make the data, programs, and other information accessible
via the bus 845. The mass storage device 830 may comprise, for
example, one or more of a solid state drive, hard disk drive, a
magnetic disk drive, an optical disk drive, or the like.
[0103] The video adapter 835 and the I/O interface 840 provide
interfaces to couple external input and output devices to the
processing unit 800. As illustrated, examples of input and output
devices include the display 810 coupled to the video adapter 835
and the mouse/keyboard/printer 815 coupled to the I/O interface
840. Other devices may be coupled to the processing unit 800, and
additional or fewer interface devices may be utilized. For example,
a serial interface such as Universal Serial Bus (USB) (not shown)
may be used to provide an interface for a printer.
[0104] The processing unit 800 also includes one or more network
interfaces 850, which may comprise wired links, such as an Ethernet
cable or the like, and/or wireless links to access nodes or
different networks 855. The network interface 850 allows the
processing unit 800 to communicate with remote units via the
networks 855. For example, the network interface 850 may provide
wireless communication via one or more transmitters/transmit
antennas and one or more receivers/receive antennas. In an
embodiment, the processing unit 800 is coupled to a local-area
network or a wide-area network 855 for data processing and
communications with remote devices, such as other processing units,
the Internet, remote storage facilities, or the like.
[0105] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the disclosure as defined by the
appended claims.
* * * * *