U.S. patent application number 11/784336 was filed with the patent office on 2007-08-09 for uplink radio access network with uplink scheduling.
This patent application is currently assigned to InterDigital Technology Corporation. Invention is credited to Stephen G. Dick, Stephen E. Terry, Guodong Zhang.
Application Number | 20070184840 11/784336 |
Document ID | / |
Family ID | 34527117 |
Filed Date | 2007-08-09 |
United States Patent
Application |
20070184840 |
Kind Code |
A1 |
Zhang; Guodong ; et
al. |
August 9, 2007 |
Uplink radio access network with uplink scheduling
Abstract
A radio access network comprises a serving radio network
controller (S-RNC). The S-RNC receives successfully received medium
access control (MAC) packet data units (PDUs), discards duplicates
of MAC PDUs, reorders the non-discarded MAC PDUs based on serial
numbers of the MAC PDUs and delivers the MAC PDUs to a radio link
control protocol layer. A controlling radio network controller
(C-RNC) provides information to Node-Bs under its control for use
in scheduling uplink transmissions. A plurality of Node-Bs schedule
uplink transmissions in response to the information provided by its
C-RNC, transmit scheduling information to user equipments of its
cells, receive MAC PDUs from user equipments of its cells using
hybrid automatic repeat request and forward the successfully
received MAC PDUs to an associated S-RNC.
Inventors: |
Zhang; Guodong;
(Farmingdale, NY) ; Terry; Stephen E.; (Northport,
NY) ; Dick; Stephen G.; (Nesconset, NY) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.;DEPT. ICC
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
InterDigital Technology
Corporation
Wilmington
DE
|
Family ID: |
34527117 |
Appl. No.: |
11/784336 |
Filed: |
April 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10939256 |
Sep 10, 2004 |
7206581 |
|
|
11784336 |
Apr 6, 2007 |
|
|
|
60517779 |
Nov 5, 2003 |
|
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Current U.S.
Class: |
455/442 |
Current CPC
Class: |
H04L 1/1829 20130101;
H04L 1/08 20130101; H04L 1/1812 20130101; H04W 36/02 20130101; H04W
36/18 20130101 |
Class at
Publication: |
455/442 |
International
Class: |
H04Q 7/20 20060101
H04Q007/20 |
Claims
1. A radio access network comprising: a serving radio network
controller (S-RNC) receives successfully received medium access
control (MAC) packet data units (PDUs), discards duplicates of MAC
PDUs, reorders the non-discarded MAC PDUs based on serial numbers
of the MAC PDUs and delivers the MAC PDUs to a radio link control
protocol layer; a controlling radio network controller (C-RNC)
provides information to Node-Bs under its control for use in
scheduling uplink transmissions; and a plurality of Node-Bs, each
Node-B schedules uplink transmissions in response to the
information provided by its C-RNC, transmits scheduling information
to user equipments of its cells, receives MAC PDUs from user
equipments of its cells using hybrid automatic repeat request and
forwards the successfully received MAC PDUs to an associated
S-RNC.
2. The radio access network of claim 1 wherein each Node-B checks a
cyclic redundancy check of the MAC PDUs to determine whether the
MAC PDU was received successfully.
3. The radio access network of claim 1 wherein only successfully
received MAC PDUs are forwarded to the S-RNC.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/939,256, filed Sep. 10, 2004, which claims
priority from U.S. Provisional Patent Application Ser. No.
60/517,779, filed Nov. 5, 2003, which is incorporated by reference
as if fully set forth herein.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of wireless
communications. More specifically, the present invention relates to
processing data blocks in a multi-cell wireless communication
system, such as a frequency division duplex (FDD) or time division
duplex (TDD) system.
BACKGROUND
[0003] Methods for improving uplink coverage, throughput and
transmission latency are currently being investigated in third
generation partnership project (3GPP) in the context of the Release
6 (R6) universal mobile telecommunications system (UMTS) study item
"FDD uplink enhancements".
[0004] It is widely anticipated that in order to achieve these
goals, Node-B (base station) will take over the responsibility of
scheduling and assigning uplink resources (physical channels) to
users. The principle is that Node-B can make more efficient
decisions and manage uplink radio resources on a short-term basis
better than the radio network controller (RNC), even if the RNC
retains coarse overall control. A similar approach has already been
adopted in the downlink for Release 5 (R5) high speed downlink
packet access (HSDPA) in both UMTS FDD and TDD modes.
[0005] It is also envisioned there could be several independent
uplink transmissions processed between a wireless transmit/receive
unit (WTRU) and a universal terrestrial radio access network
(UTRAN) within a common time interval. One example of this would be
medium access control (MAC) layer hybrid automatic repeat request
(HARQ) or simply MAC layer automatic repeat request (ARQ) operation
where each individual transmission may require a different number
of retransmissions to be successfully received by UTRAN. To limit
the impact on system architecture, it is expected that protocol
layers above the MAC should not be affected by introduction of the
enhanced uplink dedicated channel (EU-DCH). One requirement that is
introduced by this is the in-sequence data delivery to the radio
link control (RLC) protocol layer. Therefore, similar to HSDPA
operation in the downlink, a UTRAN re-ordering function is needed
to organize the received data blocks according to the sequence
generated by the WTRU RLC entity.
[0006] A soft handover macro-diversity operation requires
centralized control of uplink transmissions in each cell within an
active set. The active set may include a plurality of Node-Bs.
Retransmissions are generated until successful transmission is
realized by at least one of the Node-Bs. Successful transmission is
not guaranteed at all of the Node-Bs. Therefore, since a complete
set of successful transmissions may not be available within any one
Node-B, re-ordering of successful transmissions cannot be
accomplished.
SUMMARY
[0007] A radio access network comprises a serving radio network
controller (S-RNC). The S-RNC receives successfully received medium
access control (MAC) packet data units (PDUs), discards duplicates
of MAC PDUs, reorders the non-discarded MAC PDUs based on serial
numbers of the MAC PDUs and delivers the MAC PDUs to a radio link
control protocol layer. A controlling radio network controller
(C-RNC) provides information to Node-Bs under its control for use
in scheduling uplink transmissions. A plurality of Node-Bs schedule
uplink transmissions in response to the information provided by its
C-RNC, transmit scheduling information to user equipments of its
cells, receive MAC PDUs from user equipments of its cells using
hybrid automatic repeat request and forward the successfully
received MAC PDUs to an associated S-RNC.
BRIEF DESCRIPTION OF THE DRAWING(S)
[0008] A more detailed understanding of the invention may be had
from the following description of a preferred embodiment, given by
way of example, and to be understood in conjunction with the
accompanying drawings wherein:
[0009] FIG. 1 is a block diagram of a wireless communication system
for processing data blocks in a serving-RNC in accordance with a
preferred embodiment of the present invention;
[0010] FIG. 2 is a flowchart of a process including method steps
for processing data blocks in the system of FIG. 1;
[0011] FIG. 3 is a block diagram of a wireless communication system
for processing data blocks in a controlling-RNC in accordance with
an alternate embodiment of the present invention; and
[0012] FIG. 4 is a flowchart of a process including method steps
for processing data blocks in the system of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0013] The present invention will be described with reference to
the drawing figures wherein like numerals represent like elements
throughout.
[0014] Hereafter, the terminology "WTRU" includes but is not
limited to a user equipment (UE), a mobile station, a fixed or
mobile subscriber unit, a pager, or any other type of device
capable of operating in a wireless environment. When referred to
hereafter, the terminology "base station" includes but is not
limited to a Node-B, a site controller, an access point or any
other type of interfacing device in a wireless environment.
[0015] The present invention may be further applicable to TDD, FDD,
and time division synchronous code division multiple access
(TD-SCDMA), as applied to UMTS, CDMA 2000 and CDMA in general, but
is envisaged to be applicable to other wireless systems as well.
With respect to CDMA2000, the present invention may be implemented
in EV-DO (i.e., data only) and EV-DV (i.e., data and voice).
[0016] The features of the present invention may be incorporated
into an IC or be configured in a circuit comprising a multitude of
interconnecting components.
[0017] During soft handover, higher layers maintain an active
subset of EU cells for which EU-DCHs are maintained in a soft
handover macro diversity state. Those cells in the active subset
may be controlled by different EU-SHO Node-Bs.
[0018] FIG. 1 shows a wireless communication system 100 including
an S-RNC 105 and at least two (2) EU-SHO Node-Bs 110 (110A . . .
110N) operating in accordance with a preferred embodiment of the
present invention. One or more re-ordering function entities 115
are implemented at the S-RNC 105 for each WTRU with and without
soft handover. The HARQ or ARQ processes for handling EU-DCH
functionalities are located in a MAC entity 120 located within each
respective EU-SHO Node-B 110. Each re-ordering function entity 115
communicates with higher protocol layers 125 within the S-RNC 105
and includes an associated data buffer (not shown).
[0019] FIG. 2 is a flowchart of a process 200 including method
steps for processing data blocks, i.e., packet data units (PDUs),
in the system 100 during a soft handover. In step 205, a data
block, (i.e., an EU data block), is received at each EU-SHO Node-B
110 from a WTRU. In step 210, each EU-SHO Node-B 110 decodes the
received data block, and the decoded data block is forwarded to the
S-RNC 105. It should be noted that each EU-SHO Node-B 110 will
attempt to decode received EU transmissions. When there is a CRC
error, the EU-SHO Node-B 110 cannot forward the received data block
to the S-RNC 105, unless the identity of the WTRU and logical
channel/MAC-d flow is known by other means. All successfully
decoded blocks with good CRC check results are forwarded to the
S-RNC 105.
[0020] Still referring to FIG. 2, a determination is made as to
whether or not at least one copy of a successfully decoded data
block is received by the S-RNC 105 from an EU-SHO Node-B 110 (step
215). If it is determined in step 215 that the S-RNC 105 has not
received any copy of a successfully decoded data block, the
forwarded data block is regarded as not having been correctly
received (step 220). If, in step 215, it is determined that at
least one copy of a successfully decoded data block has been
received by the S-RNC 105 from an EU-SHO Node-B 110, a
determination is then made as to whether or not multiple copies of
the successfully decoded data block are received from different
EU-SHO Node-Bs 110 (step 225).
[0021] If step 225 determines that multiple copies of the
successfully decoded data block are received from different EU-SHO
Node-Bs 110, only one copy will be stored in a re-ordering buffer
(not shown) maintained by a re-ordering function entity 115 in the
S-RNC 105 as a correctly received data block, and any extra
received copies of the successfully decoded data block are
discarded as redundant data (step 230).
[0022] Finally, in step 235, the successfully decoded data block is
processed by the re-ordering function entity 115 in the S-RNC 105.
The re-ordering function entity 115 in the S-RNC 105 performs a
re-ordering procedure on those successfully decoded data blocks
that are correctly received in the re-ordering function entity 115
so as to support in-sequence delivery to the higher protocol layers
125.
[0023] Process 200 is beneficial because data blocks received from
different EU-SHO Node-Bs 110 can be combined and organized
in-sequence for delivery to the higher protocol layers 125 of the
S-RNC 105. The re-ordering function entity 115 located within the
S-RNC 105 allows enhanced uplink MAC PDU's to be processed for
successful reception and proper delivery to higher layers
independent of which Node-B(s) that provided reception of each PDU,
resulting in the reduction of loss of MAC data and RLC
recoveries.
[0024] FIG. 3 shows a wireless communication system 300 including a
C-RNC 305 and at least two (2) EU-SHO Node-Bs 110 (110A . . . 110N)
operating in accordance with an alternate embodiment of the present
invention. One or more re-ordering function entities 315 are
implemented at the C-RNC 305 for support of soft handover. The HARQ
or ARQ processes for handling EU-DCH functionalities are located in
a MAC entity 320 located within each respective EU-SHO Node-B 310.
Each re-ordering function entity 315 communicates with higher
protocol layers 325 external to the C-RNC 305 and includes an
associated buffer (not shown).
[0025] FIG. 4 is a flowchart of a process 400 including method
steps for processing data blocks, i.e., PDUs, in the system 300
during a soft handover. In step 405, a data block (i.e., an EU data
block) is received at each EU-SHO Node-B 310 from a WTRU. In step
410, each EU-SHO Node-B 310 decodes the received data block, and
the decoded data block is forwarded to the C-RNC 305. It should be
noted that each EU-SHO Node-B 310 will attempt to decode received
EU transmissions. When there is a CRC error, the EU-SHO Node-B 310
cannot forward the received data block to the C-RNC 305, unless the
identity of the WTRU and logical channel/MAC-d flow is known by
other means. All successfully decoded blocks with good CRC check
results are forwarded to the C-RNC 305.
[0026] Still referring to FIG. 4, a determination is made as to
whether or not at least one copy of a successfully decoded data
block is received by the C-RNC 305 from an EU-SHO Node-B 310 (step
415). If it is determined in step 415 that the C-RNC 305 has not
received any copy of a successfully decoded data block, the decoded
data block forwarded by the EU-SHO Node-Bs 310 is regarded as not
having been correctly received (step 420).
[0027] If, in step 415, it is determined that at least one copy of
a successfully decoded data block has been received by the C-RNC
305 from an EU-SHO Node-B 310, a determination is then made as to
whether or not multiple copies of the successfully decoded data
block are received from different EU-SHO Node-Bs 110 (step
425).
[0028] If step 425 determines that multiple copies of the
successfully decoded data block are received from different EU-SHO
Node-Bs 310, only one copy will be stored in a re-ordering buffer
(not shown) maintained by a re-ordering function entity 315 in the
C-RNC 305 as a correctly received data block, and any extra
received copies of the successfully decoded data block are
discarded as redundant data (step 430).
[0029] Finally, in step 435, the successfully decoded data block is
processed by the re-ordering function entity 315 in the C-RNC 305,
which performs a re-ordering procedure on those successfully
decoded data blocks that are correctly received in the re-ordering
function entity 315 so as to support in-sequence delivery to the
higher protocol layers 325.
[0030] Process 400 is beneficial because data blocks received from
different EU-SHO Node-Bs 310 can be combined and organized in
sequence for delivery to the higher protocol layers 325, provided
that these Node-Bs 310 have the same C-RNC 305. This is frequently
the case, although its applicability is somewhat more restrictive
than placing a re-ordering function in an S-RNC 105. However, this
restriction is offset by other considerations. For example, a
benefit of C-RNC operation is reduced latency for H-ARQ operation.
The performance benefits of minimizing this latency are well
understood in the art. During soft handover, it is also desirable
to have a common uplink scheduler in the C-RNC 305 for all of the
cells that are in the active EU subset, including cells that are
controlled by different Node-Bs 310.
[0031] While this invention has been particularly shown and
described with reference to preferred embodiments, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the scope of
the invention described hereinabove.
* * * * *