U.S. patent application number 15/426283 was filed with the patent office on 2017-10-26 for mac architecture in wireless communication systems supporting h-arq.
The applicant listed for this patent is Intel Corporation. Invention is credited to Nader Bolourchi, Stephen E. Terry.
Application Number | 20170310430 15/426283 |
Document ID | / |
Family ID | 23347054 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170310430 |
Kind Code |
A1 |
Terry; Stephen E. ; et
al. |
October 26, 2017 |
MAC ARCHITECTURE IN WIRELESS COMMUNICATION SYSTEMS SUPPORTING
H-ARQ
Abstract
A medium access control-high speed (MAC-hs) comprises a hybrid
automatic repeat request (H-ARQ) device configured to receive data
blocks over a wideband-code division multiple access (W-CDMA) high
speed-downlink shared channel (HS-DSCH). The H-ARQ device generates
an acknowledgement (ACK) or negative acknowledgement (NACK) for
each said data block received. Each received data block having a
transmission sequence number. The H-ARQ device receives a new
transmission instead of a pending retransmission at any time. At
least one reordering device has an input configured to receive an
output of the H-ARQ device and the at least one reordering device
configured to reorder the received data blocks based on each
received data block's transmission sequence number (TSN). Received
data blocks are immediately forwarded for processing for higher
layers when the received data blocks are received in sequence.
Inventors: |
Terry; Stephen E.;
(Northport, NY) ; Bolourchi; Nader; (Larchmont,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Intel Corporation |
Santa Clara |
CA |
US |
|
|
Family ID: |
23347054 |
Appl. No.: |
15/426283 |
Filed: |
February 7, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14722380 |
May 27, 2015 |
9596058 |
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15426283 |
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13892759 |
May 13, 2013 |
9072115 |
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14722380 |
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13588775 |
Aug 17, 2012 |
8484525 |
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13892759 |
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12144415 |
Jun 23, 2008 |
8271844 |
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13588775 |
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11365148 |
Mar 1, 2006 |
7392452 |
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12144415 |
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10270822 |
Oct 15, 2002 |
7376879 |
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11365148 |
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60343661 |
Oct 19, 2001 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1887 20130101;
H04L 1/1816 20130101; H04L 1/1861 20130101; H04B 7/2631 20130101;
H04W 72/10 20130101; H04W 72/1247 20130101; H04L 1/1819
20130101 |
International
Class: |
H04L 1/18 20060101
H04L001/18; H04W 72/10 20090101 H04W072/10; H04L 1/18 20060101
H04L001/18; H04L 1/18 20060101 H04L001/18; H04L 1/18 20060101
H04L001/18; H04W 72/12 20090101 H04W072/12; H04B 7/26 20060101
H04B007/26 |
Claims
1-5. (canceled)
6. An apparatus of an evolved NodeB (eNB), the apparatus
comprising: an interface for communication with a user equipment
(UE); and processing circuitry in communication with the interface
and arranged to: encode data in medium access control (MAC)
transport blocks for transmission to the UE; set a new data
indicator (NDI) to indicate that the data is new data rather than
retransmission data; cause the interface to transmit the data to
the UE through the interface; decode, in response to the
transmission of the data, a hybrid automatic repeat request (HARQ)
response from the UE; determine, in response to a determination
that the HARQ response is a negative acknowledgement (NACK),
whether a failure criterion for transmission of the data has been
reached; retransmit the data in response to a determination that
the failure criterion for the transmission of the data has not been
reached; determine, in response to a determination that the failure
criterion for the transmission of the data has been reached,
whether other data of another transmission is pending; and in
response to a determination that the other data is pending:
prioritize transmission of the other data over a retransmission of
the data; reset the NDI to indicate that data to be transmitted is
new data rather than a retransmission of the data; encode the other
data in other MAC transport blocks for transmission to the UE;
cause the interface to transmit the other data to the UE through
the interface; and after transmission of the other data, initiate a
HARQ process for the data: reset the NDI to indicate that data to
be transmitted is new data rather than retransmission of the other
data; and reinitiate transmission of the data to the UE through the
interface via the HARQ process.
7. The apparatus of claim 6, wherein the processing circuitry is
further configured to: decode, in response to the transmission of
the other data, another HARQ response from the UE; determine, in
response to a determination that the other HARQ response is a NACK,
whether a failure criterion for transmission of the other data has
been reached; in response to a determination that the failure
criterion for the transmission of the other data has not been
reached: prioritize retransmission of the other data over
retransmission of the data; and cause the interface to retransmit
the other data via a HARQ process.
8. The apparatus of claim 6, wherein the processing circuitry is
further configured to: prioritize retransmission of the data over
retransmission of the other data in response to a determination
that the failure criterion for the transmission of the other data
has been reached, and initiate the HARQ process for the data.
9. The apparatus of claim 6, wherein the processing circuitry is
further configured to: maintain the NDI to indicate that data to be
transmitted is retransmission data rather than new data in response
to a determination that the HARQ response is a NACK and that the
failure criterion for the transmission of the data has not been
reached.
10. The apparatus of claim 6, wherein: the failure criterion
comprises a number of retransmissions.
11. The apparatus of claim 6, wherein: retransmission of the data
occurs until a predetermined Block Error Rate (BLER) is met.
12. The apparatus of claim 6, wherein the processing circuitry is
further configured to: determine whether the other data is pending
during transmission of the MAC transport blocks of the data;
determine a type of the data and the other data; and prioritize
between transmission of the data and the other data based on the
data type independent of whether the failure criterion for the
transmission of the data has been reached.
13. The apparatus of claim 12, wherein the processing circuitry is
further configured to: interrupt transmission of lower priority
data in favor of transmission of higher priority data.
14. The apparatus of claim 12, wherein the processing circuitry is
further configured to: prioritize control data over retransmission
data.
15. The apparatus of claim 6, wherein the processing circuitry is
further configured to: select a modulation coding scheme for a
current transmission of the data dependent on a number of previous
transmissions of the data; and cause the interface to transmit the
current transmission of the data in accordance with the modulation
coding scheme.
16. The apparatus of claim 6, wherein the processing circuitry is
further configured to: select a modulation coding scheme for a
current transmission of the data dependent on a transmission
channel used for transmission of the data; and cause the interface
to transmit the current transmission of the data in accordance with
the modulation coding scheme.
17. An apparatus of a user equipment (UE), the apparatus
comprising: an interface for communication with an evolved NodeB
(eNB); and processing circuitry in communication with the interface
and arranged to: decode data in medium access control (MAC)
transport blocks from the eNB; determine, from a new data indicator
(NDI), whether the data is new data or retransmission data; encode
a hybrid automatic repeat request (HARQ) response to the data for
transmission to the eNB through the interface; and combine a
current transmission of the data with a previous transmission of
the data in response to the NDI indicating that the data is
retransmission data, wherein the NDI indicates that the data is the
new data, after a negative acknowledgement (NACK) HARQ response, in
response to at least one of a determination that a failure
criterion for the transmission of the data has been reached or
higher priority data having a higher priority than the data is to
be transmitted, and transmission of the new data is prioritized
over retransmission of the data via a HARQ process after the
failure criterion for the transmission of the data has been
reached.
18. The apparatus of claim 17, wherein: the processing circuitry is
further configured to encode, in response to the NDI indicating
that the data is new data, another HARQ response to the eNB, and
transmission of the retransmission of the data is prioritized over
retransmission of the new data via the HARQ process after the
failure criterion for the transmission of the new data has been
reached.
19. The apparatus of claim 17, wherein: the failure criterion
comprises a number of retransmissions.
20. The apparatus of claim 17, wherein: retransmission of the data
occurs until a predetermined Block Error Rate (BLER) is met.
21. The apparatus of claim 17, wherein: a priority of the data and
the higher priority data is based on a type of the data and the
higher priority data; and prioritization between the data and the
higher priority data is independent of whether the failure
criterion for the transmission of the data has been reached.
22. The apparatus of claim 21, wherein: transmission of lower
priority data is interrupted in favor of transmission of higher
priority data.
23. The apparatus of claim 22, wherein: transmission of control
data is prioritized over retransmission of data.
24. The apparatus of claim 17, wherein: a modulation coding scheme
for a current transmission of the data is dependent on a number of
previous transmissions of the data.
25. The apparatus of claim 17, wherein the processing circuitry is
further configured to: a modulation coding scheme for a current
transmission of the data is dependent on a transmission channel
used for transmission of the data.
26. A non-transitory computer-readable storage medium that stores
instructions for execution by processing circuitry of an evolved
NodeB (eNB), the processing circuitry to configure the eNB to:
encode data in medium access control (MAC) transport blocks for
transmission to the UE; set a new data indicator (NDI) to indicate
that the data is new data rather than retransmission data; transmit
the data to the UE through the interface; decode, in response to
the transmission of the data, a hybrid automatic repeat request
(HARQ) response from the UE; determine, in response to a
determination that the HARQ response is a negative acknowledgement
(NACK), whether a number of retransmissions of the data has been
reached; determine, in response to a determination that the number
of retransmissions of the data has been reached, whether other data
of another transmission is pending; and in response to a
determination that the other data is pending and that the number of
retransmissions of the data has been reached or the other data has
a higher priority than the data: prioritize transmission of the
other data over the data; reset the NDI to indicate that data to be
transmitted is new data rather than a retransmission of the data;
encode the other data in other MAC transport blocks for
transmission to the UE; transmit the other data to the UE through
the interface; and after transmission of the other data, initiate a
HARQ process for the data: reset the NDI to indicate that data to
be transmitted is new data rather than retransmission of the other
data; and reinitiate transmission of the data to the UE through the
interface via the HARQ process.
27. The medium of claim 26, wherein the instructions further
configure the eNB to: determine a type of the data and the other
data; prioritize between transmission of the data and the other
data based on the data type independent of whether the number of
transmissions of the data has been reached; and interrupt
transmission of lower priority data in favor of transmission of
higher priority data.
28. The medium of claim 26, wherein the instructions further
configure the eNB to: select a modulation coding scheme for a
current transmission of the data dependent on a number of previous
transmissions of the data; and transmit the current transmission of
the data in accordance with the modulation coding scheme.
29. The medium of claim 26, wherein the instructions further
configure the eNB to: select a modulation coding scheme for a
current transmission of the data dependent on a transmission
channel used for transmission of the data; and transmit the current
transmission of the data in accordance with the modulation coding
scheme.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/144,415 filed Jun. 23, 2008, which is a
continuation of U.S. patent application Ser. No. 11/365,148 filed
Mar. 1, 2006, which issued on Jun. 24, 2008 as U.S. Pat. No.
7,392,452, which is a continuation of U.S. patent application Ser.
No. 10/270,822 filed Oct. 15, 2002, which issued on May 20, 2008 as
U.S. Pat. No. 7,376,879, which claims priority from U.S.
Provisional Patent Application No. 60/343,661 filed Oct. 19, 2001,
all of which are incorporated by reference as if fully set
forth.
BACKGROUND
[0002] The present invention is related to MAC architecture in a
wireless communication system where Hybrid Automatic Repeat Request
(H-ARQ) techniques are applied.
[0003] A block diagram of the UMTS Terrestrial Radio Access Network
(UTRAN) MAC-hs layer architecture is illustrated in FIG. 1, and a
block diagram of the user equipment (UE) MAC-hs architecture is
shown in FIG. 2. The UTRAN MAC-hs 30 shown in FIG. 1 comprises a
Transport Format Combination (TFC) selection entity 31, a
scheduling device 32, a plurality of H-ARQ processors 33a, 33b and
a flow controller 34.
[0004] The UE MAC-hs 40 comprises an H-ARQ processor 41. As will be
explained in further detail hereinafter, with reference to both
FIGS. 1 and 2, the H-ARQ processors 33a, 33b in the UTRAN MAC-hs 30
and the H-ARQ processor 41 in the UE MAC-hs 40 work together to
process blocks of data.
[0005] The H-ARQ processors 33a, 33b in the UTRAN MAC-hs 30 handle
all of the tasks that are required for H-ARQ to generate
transmissions and retransmissions for any transmission that is in
error. The H-ARQ processor 41 in the UE MAC-hs 40 is responsible
for generating acknowledgements (ACKs) to indicate a successful
transmission and negative acknowledgements (NACKs) in the case of
failed transmissions. The H-ARQ processors 33a, 33b and 41 process
sequential data streams for each user data flow. Blocks of data
received on each user data flow are sequentially assigned to H-ARQ
processors 33a, 33b. Each H-ARQ processor 33a, 33b initiates a
transmission, and in the case of an error, the H-ARQ processor 41
requests a retransmission. On subsequent transmissions, the
modulation and coding rate may be changed in order to ensure a
successful transmission. The H-ARQ processor 41 in the UE MAC-hs 40
may combine the soft information from the original transmission and
any subsequent retransmissions. The data to be retransmitted and
any new transmissions to the UE are forwarded to the scheduling
device 32.
[0006] The scheduling device 32, coupled between the H-ARQ
processors 33a, 33b and the TFC selector 31, functions as radio
resource manager and determines transmission latency in order to
support the required QoS. Based on the outputs of the H-ARQ
processors 33a, 33b and the priority of new data being transmitted,
the scheduling device 32 forwards the data to the TFC selection
entity 31.
[0007] The TFC selection entity 31, coupled to the scheduling
device 32, receives the data to be transmitted and selects an
appropriate dynamic transport format for the data to be
transmitted. With respect to H-ARQ transmissions and
retransmissions, the TFC selection entity 31 determines modulation
and coding.
[0008] Data streams are processed sequentially, and each data block
is processed until successful transmission is achieved or the
transmission fails and the data is discarded. Retransmissions
signaled by the H-ARQ process take precedence over any new data to
be transmitted. Each H-ARQ processor 33a, 33b performs
transmissions and retransmissions until the data block transmission
is determined successful or failed. Using this scheme, higher
priority data transmissions may be delayed while lower priority
data retransmissions are processed until success or failure is
determined.
[0009] UE connections require support of several independent
traffic control signaling channels. Each of these channels has QoS
requirements, which include guaranteed and/or acceptable
transmission latency levels. Since the H-ARQ processing is taken
into account prior to scheduling, it is not possible for higher
priority data to supercede lower priority data retransmissions.
Therefore, the transmission latency QoS requirements for high
priority data transmissions may not be achievable when low priority
data transmissions have been previously assigned to H-ARQ
processors 33a, 33b.
[0010] Since retransmissions are combined with previous
transmissions in the H-ARQ process, it is possible that if the
first transmissions are sufficiently corrupted, subsequent
retransmissions will not achieve successful transmission. In this
case since transmissions can not be reinitiated as new
transmissions from the scheduling entity 32, data is discarded.
[0011] Accordingly, there exists a need for an improved MAC-hs
architecture both in the UTRAN and UE that allows for higher
priority transmissions to supercede lower priority transmissions
and for the ability to reinitiate transmissions at any time.
SUMMARY
[0012] A medium access control-high speed (MAC-hs) comprises a
hybrid automatic repeat request (H-ARQ) device configured to
receive data blocks over a wideband-code division multiple access
(W-CDMA) high speed-downlink shared channel (HS-DSCH). The H-ARQ
device generates an acknowledgement (ACK) or negative
acknowledgement (NACK) for each said data block received. Each
received data block having a transmission sequence number. The
H-ARQ device receives a new transmission instead of a pending
retransmission at any time. At least one reordering device has an
input configured to receive an output of the H-ARQ device and the
at least one reordering device configured to reorder the received
data blocks based on each received data block's transmission
sequence number (TSN). Received data blocks are immediately
forwarded for processing for higher layers when the received data
blocks are received in sequence.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a prior art UTRAN MAC-hs.
[0014] FIG. 2 is a prior art UE MAC-hs.
[0015] FIG. 3 is a block diagram of a UTRAN MAC-hs in accordance
with the preferred embodiment of the present invention.
[0016] FIG. 4 is a block diagram of a UE MAC-hs in accordance with
the preferred embodiment of the present invention.
[0017] FIG. 5 is a flow diagram of a procedure for permitting
higher priority transmissions to interrupt lower priority
transmissions to achieve transmission latency requirements.
[0018] FIG. 6 is a flow diagram of a procedure to re-initiate
failed transmissions to achieve Block Error Rate requirements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The preferred embodiments will be described with reference
to the drawing figures where like numerals represent like elements
throughout.
[0020] FIG. 3 is a block diagram of the UTRAN MAC-hs 50, preferably
located at the Node B, in accordance with the preferred embodiment
of the present invention. The UTRAN MAC-hs 50 comprises a TFC
selector 51, a plurality of H-ARQ entities 52a, 52b, a scheduling
and prioritization entity 53, a priority class and TSN setting
entity 54 and a flow controller 55. As will be explained in detail,
the components of the UTRAN MAC-hs 50 are coupled together in a
novel manner, which facilitates proper scheduling prioritization
for greater ability to achieve transmission latency requirements
and the ability to reinitiate transmissions at any time to reduce
transmission errors within the UTRAN MAC-hs 50 (shown in FIG. 3)
and UE MAC-hs 60 (shown in FIG. 4).
[0021] Similar to the prior art flow controller 34 discussed
hereinbefore, the flow controller 55 of the present invention shown
in FIG. 3, and, coupled to the MAC-c/sh of the RNC (not shown) and
the priority class and TSN setting entity 54, provides a controlled
data flow between the Node B and the RNC, taking the transmission
capabilities of the air interface into account in a dynamic manner.
Although shown in FIG. 3 as separate components, the functionality
of the scheduling and prioritization handling entity 53
(hereinafter, the "scheduling entity 53") and the priority class
and TSN setting entity 54 (hereinafter, the "TSN setting entity
54") may be combined into a single entity.
[0022] TSN setting entity 54 is coupled between the flow controller
55 and the scheduling entity 53. The TSN setting entity 54 of the
present invention sets, for each priority class, a queue identifier
and TSN for each new data block being serviced to ensure sequence
in delivery of data blocks to higher layers. The TSN is unique to
each priority class and queue identity within a high speed downlink
shared channel (HS-DSCH), and is incremented for each new data
block. Once a queue identifier and the TSN have been set for a new
data block, the data block is forwarded to the scheduling entity
53.
[0023] The scheduling entity 53 processes data received from the
TSN setting entity 54. The scheduling entity 53 functions as a
radio resource manager for the cell, as well as maintaining QoS
requirements for the users serviced by the UTRAN MAC-hs 50. The TSN
and priority class identifiers for the data blocks to be
transmitted are forwarded to the scheduling entity 53.
[0024] In accordance with the present invention, the scheduling
entity 53 ensures proper prioritization of transmissions according
to data flow QoS latency requirements and allows for reinitiation
of failed H-ARQ transmissions that permits the greater ability to
achieve QoS Block Error Rate (BLER) requirements. These abilities
of the scheduling entity 53 are not possible when H-ARQ processing
precedes the scheduling function as in the prior art system of FIG.
1. The scheduling entity 53 manages HS-DSCH physical resources
between the H-ARQ entities 52a, 52b and data flows according to
their QoS requirements for transmission latency and transport
channel BLER requirements. Beside the QoS parameters, the
scheduling algorithm used by the scheduling entity 53 may also
operate according to, for example, various radio control resource
parameters such as the signal-to-interference ratio (SIR),
available and rate, speed of the UE, current load of the cell and
other factors that are well known to those of skill in the art. The
scheduling entity 53 determines the data (associated with a
particular UE), and the H-ARQ entities 52a,52b that will service
the transmission.
[0025] The transmission assigned to the H-ARQ, 52a,52b is either a
new transmission, or a retransmission of data that previously was
not successfully delivered. Status reports from the previous
transmission signaled between the UE H-ARQ entity 61 (shown in FIG.
4) and the UTRAN H-ARQ entities 52a, 52b (shown in FIG. 3) are
relayed to the scheduling entity 53 where it is determined whether
a new or retransmission will be serviced. The UTRAN MAC-hs 50
architecture defined by the present invention allows the scheduling
entity 53, at any time, to determine whether or not to permit new
transmissions to be initiated on an H-ARQ entity 52a, 52b. New
transmissions may be higher priority transmissions that need to
supercede lower priority transmissions to achieve QoS transmission
latency requirements, or re-initiation of previously failed or
interrupted transmissions to achieve QoS transport channel BLER
requirements.
[0026] The algorithm within the scheduling entity 53 schedules data
transmissions according to priority class. The UTRAN MAC-hs 50 of
the present invention allows lower priority transmissions to be
interrupted for the transmission of higher priority transmissions,
and provides the ability to reinitiate previously failed or
interrupted transmissions at any time.
[0027] The scheduling entity 53 forwards radio resource scheduling
information to the H-ARQs entities 52a, 52b. The scheduling entity
53 directs the H-ARQ entities 52a, 52b to initiate either a new
transmission or a retransmission of a previous unsuccessful
transmission by the particular H-ARQ entity 52a, 52b. The data is
then forwarded to the TFC selector 51 for transmission. The TFC
selector 51, coupled to the H-ARQ processors 52a, 52b, receives the
transmissions and selects an appropriate dynamic transport format
parameter for the data to be transmitted to the UE. Although shown
in FIG. 3 as separate components, the functionality of the H-ARQ
entities 52a, 52b and the TFC selector 51 may be combined into a
single entity.
[0028] A block diagram of a UE MAC-hs layer 60 for a UE in
accordance with the preferred embodiment of the present invention
is illustrated in FIG. 4. The UE MAC-hs 60 comprises a plurality of
reordering devices 62a, 62b and an H-ARQ entity 61. Similar to the
H-ARQ processor 41 described hereinbefore with respect to the
UTRAN, the UE H-ARQ entity 61 is responsible for handling all the
processes for implementing the H-ARQ protocol. Within the UE, the
receiving H-ARQ entity 61 combines the soft information from the
original transmission and any subsequent retransmissions.
[0029] Within the H-ARQ protocol layer, individual transmission
priority classes and the required sequence of delivery (TSNs) are
not known. Accordingly, successful reception transmissions are
reordered according to their TSN by the reordering devices 62a,
62b. The reordering devices 62a, 62b immediately forward for
processing in higher layers transmissions following in sequence
reception.
[0030] The MAC-hs process in accordance with the preferred
embodiment of the present invention ensures that higher priority
transmissions are not delayed by processing of lower priority
transmissions. Additionally, transmissions can be reinitiated at
any time, thereby reducing the transmission failure rate within the
MAC-hs process. This gives the scheduling entity 53 the ability to
utilize the input information available to determine the best
combination of transmissions to achieve maximum performance of the
system, maximum use of the radio network and maintain QoS
requirements for transmission latency and BLER.
[0031] Although the elements or processes of the present invention
have been described as discrete hardware components, for example
the scheduling entity 53 and the TSN setting entity 54, these
elements will most likely be implemented in one or more software
routines or modules. It should be understood that the overall flow
and sequence of information between each process is important, not
whether the process is implemented separately or together, or in
hardware or software.
[0032] Referring to FIG. 5, a method 100 for permitting
transmission of higher priority data to interrupt the transmission
of lower priority data to achieve transmission latency requirements
is shown. The method 100 is for communications between a
transmitter 102 (such as at the UTRAN) and a receiver 104 (such as
at the UE). The method 100 assumes communication for a particular
H-ARQ process, such as between one of the H-ARQ entities 52a, 52b
in the UTRAN and the corresponding H-ARQ entity 61 in the UE.
[0033] The method 100 commences with the setting of a new data
indicator (NDI) for the establishment of a new H-ARQ process (step
103). The lower priority data is processed (step 106) at the
transmitter 102. As aforementioned at the receiver 104, a quality
check is performed whereby an acknowledgement (ACK) is generated if
the transmission is successful (i.e. received without errors) or a
non-acknowledgment (NACK) is generated if the transmission is not
successful (step 108). The ACK or NACK is sent to the transmitter
102. Steps 106 and 108 are repeated until the transmission is
successfully received at the receiver 104, or higher-priority data
arrives at the scheduling entity (step 110) that needs to be
scheduled to meet QoS transmission latency requirements.
[0034] If higher priority data needs to be scheduled for
transmission to meet transmission latency requirements (step 110),
lower priority data transmission may be interrupted (step 112). The
H-ARQ process of transmission of the higher priority data is then
commenced (step 114). Interruption of the previous data
transmission is identified to the receiver 104 by setting of the
NDI. At the receiver 104, a quality check is performed whereby an
acknowledgement (ACK) is generated if the transmission is
successful or a non-acknowledgment (NACK) is generated if the
transmission is not successful (step 116). The ACK or NACK is then
sent to the transmitter 102. Steps 114 and 116 are repeated until
the higher priority data transmission is successfully received at
the receiver 104.
[0035] Once the transmission of the higher priority data has been
confirmed, the lower priority data transmission may then be
reinitiated (step 118). The transmission is repeated until the
quality check results in an ACK being generated by the receiver 104
(step 120). As with the aforementioned H-ARQ process, it may be
necessary to retransmit the lower priority data by the transmitter
102 in response to an NACK generated by the receiver 104.
[0036] The method 100 of FIG. 5 is an example of scheduling of an
H-ARQ process to achieve desired latency requirements for the data
to be transmitted. With the proposed UTRAN MAC architecture 50 in
accordance with the present invention, method 100 and other
sequences of operation between the transmitter 102 and receiver 104
are also possible to achieve transmission latency requirements.
[0037] Referring to FIG. 6, a method 200 for permitting
re-initiation of failed transmissions to achieve Block Error Rate
(BLER) requirements is shown. The method 200 is for communications
between a transmitter 201 (such as at the UTRAN) and a receiver 203
(such as at the UE). The method 200 assumes communication for any
set of H-ARQ processes associated with a UE, such as between one of
the H-ARQ entities 52a, 52b in the UTRAN and the corresponding
H-ARQ entity 61 in the UE.
[0038] The method 200 commences with the processing of data for
transmission (step 202) at the transmitter 201. The H-ARQ
processing for the data is performed, whereby a quality check is at
the receiver 203 is performed (step 204) and an ACK or NACK is then
sent to the transmitter 201. Steps 202 and 204 are repeated until
the data transmission is successfully received at the receiver 203
or until a retransmission limit or another failure criteria is
reached (step 206).
[0039] In the event that a failure criterion has been reached (step
206), the UTRAN MAC architecture 50 allows for re-initiation of the
failed transmission on the H-ARQ process (steps 212 and 214).
Re-initiation may be performed after the scheduling of other
pending transmissions (steps 208, 210) or may proceed directly
(steps 212, 214). Accordingly, it is possible subsequent to the
transmission or failure of one or more "other" transmissions, these
other transmissions may be scheduled (step 208) and transmitted by
the transmitter 201 and the quality check is performed and ACKs or
NACKs are generated and transmitted by the receiver 203 as
appropriate (step 210).
[0040] Once the other transmissions have been successfully sent, or
the failure criteria has been reached (steps 208-210), the
previously failed transmission may be scheduled for transmission on
the H-ARQ process (step 212). Re-initiation of the previous data
transmission is identified to the receiver 203 by setting of the
NDI. Retransmissions of the data are sent and an ACK or a NACK is
generated as appropriate (step 214). Steps 212 and 214 are repeated
until the transmission is successfully received at the receiver
203, or the retransmission limit or other failure criteria has been
reached (step 206). The reinitiation of a previously failed
transmission can be applied several times to any particular
transmission in order to achieve BLER requirements.
[0041] While the present invention has been described in terms of
the preferred embodiment, other variations which are within the
scope of the invention as outlined in the claims below will be
apparent to those skilled in the art.
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