U.S. patent application number 16/318093 was filed with the patent office on 2021-09-09 for design of hybrid automatic repeat request (harq) feedback bits for polar codes.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Jilei HOU, Jian LI, Chao WEI, Changlong XU.
Application Number | 20210281359 16/318093 |
Document ID | / |
Family ID | 1000005649538 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210281359 |
Kind Code |
A1 |
XU; Changlong ; et
al. |
September 9, 2021 |
DESIGN OF HYBRID AUTOMATIC REPEAT REQUEST (HARQ) FEEDBACK BITS FOR
POLAR CODES
Abstract
Certain aspects of the present disclosure relate to techniques
and apparatus for design of hybrid automatic repeat request (HARQ)
feedback bits. The method generally includes obtaining a payload to
be transmitted, partitioning the payload into a plurality of
blocks, and partitioning each block of the plurality of blocks into
a plurality of sections. The method also includes deriving
redundancy check information for each section of the plurality of
sections, and generating a plurality of codewords, each comprising
a block of the plurality of blocks and the redundancy check
information for each section of the block, wherein a location of
each of the sections in the codewords is determined based on an
error rate corresponding to each of the sections.
Inventors: |
XU; Changlong; (Beijing,
CN) ; LI; Jian; (Beijing, CN) ; WEI; Chao;
(Beijing, CN) ; HOU; Jilei; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005649538 |
Appl. No.: |
16/318093 |
Filed: |
July 27, 2016 |
PCT Filed: |
July 27, 2016 |
PCT NO: |
PCT/CN2016/091914 |
371 Date: |
January 15, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/0044 20130101;
H04L 1/0061 20130101; H04L 1/1812 20130101; H04L 1/0057
20130101 |
International
Class: |
H04L 1/00 20060101
H04L001/00; H04L 5/00 20060101 H04L005/00 |
Claims
1. A method for wireless communications, comprising: obtaining a
payload to be transmitted; partitioning the payload into a
plurality of blocks; partitioning each block of the plurality of
blocks into a plurality of sections; deriving redundancy check
information for each section of the plurality of sections; and
generating a plurality of codewords, each comprising a block of the
plurality of blocks and the redundancy check information for each
section of the block, wherein a location of each of the sections in
the codewords is determined based on an error rate corresponding to
each of the sections.
2. The method of claim 1, wherein the plurality of sections of each
block comprises a first section, a second section, and third
section, and wherein the first section of each block has a lower
error rate than the second section of each block and the second
section of each block has a lower error rate than the third section
of each block.
3. The method of claim 2, further comprising: receiving an
indication that the first section of each block or the second
section of each block was not properly decoded; determining whether
the third section of each block was properly decoded based on the
indication; and retransmitting the third section of each block
based on the determination.
4. The method of claim 1, further comprising receiving an
indication of whether the plurality of sections of each block were
properly decoded, wherein the plurality of sections of each block
comprise at least three sections, and where the indication
comprises a fewer number of bits than a number of sections of each
block.
5. The method of claim 1, further comprising: receiving an
indication that two sections of each block were not properly
decoded, wherein the indication comprises a bit corresponding to
each of the two sections; and re-transmitting the two sections of
each block based on the indication.
6. The method of claim 1, wherein the redundancy check information
comprises a cyclic redundancy check (CRC).
7. The method of claim 1, wherein the codewords are encoded using
polar coding.
8. A method for wireless communications, comprising: receiving a
plurality of codewords, each comprising a plurality of blocks,
wherein each of the plurality of blocks comprise a plurality of
sections and redundancy check information for each section of the
plurality of sections, wherein a location of each of the plurality
of sections of each block is determined based on an error rate
corresponding to each of the plurality of sections of each block;
decoding the plurality of sections of each block; verifying whether
the plurality of sections of each block were properly decoded based
on the redundancy check information for each of the decoded
sections; and transmitting an indication of whether the plurality
of sections of each block was properly decoded based on the
verification.
9. The method of claim 8, wherein the plurality of sections of each
block comprises at least three sections, and where the indication
comprises a fewer number of bits than a number of sections of the
plurality of sections.
10. The method of claim 8, wherein the plurality of sections of
each block comprises a first section, a second section, and third
section, and wherein the first section of each block has a lower
error rate than the second section of each block and the second
section of each block has a lower error rate than the third section
of each block.
11. The method of claim 10, wherein the indication comprises a
first bit used to indicate whether the second section of each block
was properly decoded and a second
12. The method of claim 8, further comprising: transmitting an
indication of whether two sections of each block were properly
decoded based on the verification, wherein the indication comprises
a bit corresponding to each of the two sections.
13. The method of claim 8, wherein the redundancy check information
comprises a cyclic redundancy check (CRC).
14. The method of claim 8, wherein the decoding comprises
performing CRC-aided successive cancellation list (CA-SCL) decoding
based on the redundancy check information.
15. The method of claim 8, wherein the codewords are encoded using
polar coding.
16. An apparatus for wireless communications, comprising: at least
one processor configured to: obtain a payload to be transmitted;
partition the payload into a plurality of blocks; partition each
block of the plurality of blocks into a plurality of sections;
derive redundancy check information for each section of the
plurality of sections; and generate a plurality of codewords, each
comprising a block of the plurality of blocks and the redundancy
check information for each section of the block, wherein a location
of each of the sections in the codewords is determined based on an
error rate corresponding to each of the sections; and a memory
coupled to the at least one processor.
17. An apparatus for wireless communications, comprising: at least
one antenna; a processing system configured to: receive, via the at
least one antenna, a plurality of codewords, each comprising a
plurality of blocks, wherein each of the plurality of blocks
comprise a plurality of sections and redundancy check information
for each sections of each block is determined based on an error
rate corresponding to each of the plurality of sections of each
block; decode the plurality of sections of each block; verify
whether the plurality of sections of each block were properly
decoded based on the redundancy check information for each of the
decoded sections; and transmit, via the at least one antenna, an
indication of whether the plurality of sections of each block was
properly decoded based on the verification.
18. An apparatus for wireless communications, comprising: means for
obtaining a payload to be transmitted; means for partitioning the
payload into a plurality of blocks; means for partitioning each
block of the plurality of blocks into a plurality of sections;
means for deriving redundancy check information for each section of
the plurality of sections; and means for generating a plurality of
codewords, each comprising a block of the plurality of blocks and
the redundancy check information for each section of the block,
wherein a location of each of the sections in the codewords is
determined based on an error rate corresponding to each of the
sections.
19. An apparatus for wireless communications, comprising: means for
receiving, via the at least one antenna, a plurality of codewords,
each comprising a plurality of blocks, wherein each of the
plurality of blocks comprise a plurality of sections and redundancy
check information for each section of the plurality of sections,
wherein a location of each of the plurality of sections of each
block is determined based on an error rate corresponding to each of
the plurality of sections of each block; means for decoding the
plurality of sections of each block; means for verifying whether
the plurality of sections of each block were properly decoded based
on the redundancy check information for each of the decoded
sections; and means for transmitting an indication of whether the
plurality of sections of each block was properly decoded based on
the verification.
20. A computer-readable medium having instructions stored thereon
for: obtaining a payload to be transmitted; partitioning the
payload into a plurality of blocks; partitioning each block of the
plurality of blocks into a plurality of sections; deriving
redundancy check information for each section of the plurality of
sections; and generating a plurality of codewords, each comprising
a block of the plurality of blocks and the redundancy check
information for each section of the block, wherein a location of
each of the sections in the codewords is determined based on an
error rate corresponding to each of the sections.
21. A computer-readable medium having instructions stored thereon
for: receiving a plurality of codewords, each comprising a
plurality of blocks, wherein each of the plurality of blocks
comprise a plurality of sections and redundancy check information
for each section of the plurality of sections, wherein a location
of each of the plurality of sections of each block is determined
based on an error rate corresponding to each of the plurality of
sections of each block; decoding the plurality of sections of each
block; verifying whether the plurality of sections of each block
were properly decoded based on the redundancy check information for
each of the decoded sections; and transmitting an indication of
whether the plurality of sections of each block was properly
decoded based on the verification.
Description
FIELD
[0001] Certain aspects of the present disclosure generally relate
to wireless communications and, more particularly, to a method and
apparatus for providing feedback.
BACKGROUND
[0002] In a transmitter of all modern wireless communication links,
an output sequence of bits from an error correcting code can be
mapped onto a sequence of complex modulation symbols. These symbols
can be then used to create a waveform suitable for transmission
across a wireless channel. Particularly as data rates increase,
decoding performance on the receiver side can be a limiting factor
to achievable data rates.
SUMMARY
[0003] Certain aspects of the present disclosure provide techniques
and apparatus for design of hybrid automatic repeat request (HARQ)
feedback bits.
[0004] Certain aspects provide a method for wireless
communications. The method generally includes obtaining a payload
to be transmitted, partitioning the payload into a plurality of
blocks, partitioning each block of the plurality of blocks into a
plurality of sections, deriving redundancy check information for
each section of the plurality of sections, and generating a
plurality of codewords, each comprising a block of the plurality of
blocks and the redundancy check information for each section of the
block, wherein a location of each of the sections in the codewords
is determined based on an error rate corresponding to each of the
sections.
[0005] Certain aspects provide a method for wireless
communications. The method generally includes receiving a plurality
of codewords, each comprising a plurality of blocks, wherein each
of the plurality of blocks comprise a plurality of sections and
redundancy check information for each section of the plurality of
sections, wherein a location of each of the plurality of sections
of each block is determined based on an error rate corresponding to
each of the plurality of sections of each block, decoding the
plurality of sections of each block, verifying whether the
plurality of sections of each block were properly decoded based on
the redundancy check information for each of the decoded sections,
and transmitting an indication of whether the plurality of sections
each block were properly decoded based on the verification.
[0006] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes at least one
processor configured to obtain a payload to be transmitted,
partition the payload into a plurality of blocks, partition each
block of the plurality of blocks into a plurality of sections,
derive redundancy check information for each section of the
plurality of sections, and generate a plurality of codewords, each
comprising a block of the plurality of blocks and the redundancy
check information for each section of the block, wherein a location
of each of the sections in the codewords is determined based on an
error rate corresponding to each of the sections, and a memory
coupled to the at least one processor.
[0007] Certain aspects provide an apparatus for wireless
communications an apparatus for wireless communication. The
apparatus generally includes at least one antenna, a processing
system configured to receive, via the at least one antenna, a
plurality of codewords, each comprising a plurality of blocks,
wherein each of the plurality of blocks comprise a plurality of
sections and redundancy check information for each section of the
plurality of sections, wherein a location of each of the plurality
of sections of each block is determined based on an error rate
corresponding to each of the plurality of sections of each block,
decode the plurality of sections of each block, verify whether the
plurality of sections of each block were properly decoded based on
the redundancy check information for each of the decoded sections,
and transmit, via the at least one antenna, an indication of
whether the plurality of sections of each block was properly
decoded based on the verification.
[0008] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes means for
obtaining a payload to be transmitted, means for partitioning the
payload into a plurality of blocks, means for partitioning each
block of the plurality of blocks into a plurality of sections,
means for deriving redundancy check information for each section of
the plurality of sections, and means for generating a plurality of
codewords, each comprising a block of the plurality of blocks and
the redundancy check information for each section of the block,
wherein a location of each of the sections in the codewords is
determined based on an error rate corresponding to each of the
sections.
[0009] Certain aspects provide an apparatus for wireless
communications. The apparatus generally includes means for
receiving, via the at least one antenna, a plurality of codewords,
each comprising a plurality of blocks, wherein each of the
plurality of blocks comprise a plurality of sections and redundancy
check information for each section of the plurality of sections,
wherein a location of each of the plurality of sections of each
block is determined based on an error rate corresponding to each of
the plurality of sections of each block, means for decoding the
plurality of sections of each block, means for verifying whether
the plurality of sections of each block were properly decoded based
on the redundancy check information for each of the decoded
sections, and means for transmitting an indication of whether the
plurality of sections of each block was properly decoded based on
the verification.
[0010] Certain aspects provide a computer-readable medium having
instructions stored thereon for obtaining a payload to be
transmitted, partitioning the payload into a plurality of blocks,
partitioning each block of the plurality of blocks into a plurality
of sections, deriving redundancy check information for each section
of the plurality of sections, and generating a plurality of
codewords, each comprising a block of the plurality of blocks and
the redundancy check information for each section of the block,
wherein a location of each of the sections in the codewords is
determined based on an error rate corresponding to each of the
sections.
[0011] Certain aspects provide a computer-readable medium having
instructions stored thereon for receiving a plurality of codewords,
each comprising a plurality of blocks, wherein each of the
plurality of blocks comprise a plurality of sections and redundancy
check information for each section of the plurality of sections,
wherein a location of each of the plurality of sections of each
block is determined based on an error rate corresponding to each of
the plurality of sections of each block, decoding the plurality of
sections of each block, verifying whether the plurality of sections
of each block were properly decoded based on the redundancy check
information for each of the decoded sections, and transmitting an
indication of whether the plurality of sections of each block was
properly decoded based on the verification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] So that the manner in which the above-recited features of
the present disclosure can be understood in detail, a more
particular description, briefly summarized above, may be had by
reference to aspects, some of which are illustrated in the appended
drawings. It is to be noted, however, that the appended drawings
illustrate only certain typical aspects of this disclosure and are
therefore not to be considered limiting of its scope, for the
description may admit to other equally effective aspects.
[0013] FIG. 1 illustrates an example wireless communication system
in accordance with certain aspects of the present disclosure.
[0014] FIG. 2 illustrates a block diagram of an access point and a
user terminal in accordance with certain aspects of the present
disclosure.
[0015] FIG. 3 illustrates a block diagram of an example wireless
device in accordance with certain aspects of the present
disclosure.
[0016] FIG. 4 is a simplified block diagram illustrating a decoder,
in accordance with certain aspects of the present disclosure.
[0017] FIG. 5 is a simplified block diagram illustrating a decoder,
in accordance with certain aspects of the present disclosure.
[0018] FIG. 6A illustrates an example structure of coded blocks of
a signal transmission.
[0019] FIG. 6B illustrates an example structure of hybrid automatic
repeat request (HARQ) feedback bits.
[0020] FIG. 7 illustrates an example of operations for wireless
communication by a transmitter device, in accordance with certain
aspects of the present disclosure.
[0021] FIG. 8 illustrates an example of operations for wireless
communication by a receiver device, in accordance with certain
aspects of the present disclosure.
[0022] FIG. 9A illustrates an example structure of coded blocks
segmented into two block groups, in accordance with certain aspects
of the present disclosure.
[0023] FIG. 9B illustrates an example structure of HARQ feedback
bits for coded blocks segmented into two block groups, in
accordance with certain aspects of the present disclosure.
[0024] FIG. 10A illustrates an example structure of the coded
blocks segmented into three groups, in accordance with certain
aspects of the present disclosure.
[0025] FIG. 10B illustrates an example structure of HARQ feedback
bits for coded blocks segmented into three block groups, in
accordance with certain aspects of the present disclosure.
DETAILED DESCRIPTION
[0026] Various aspects of the disclosure are described more fully
hereinafter with reference to the accompanying drawings. This
disclosure may, however, be embodied in many different forms and
should not be construed as limited to any specific structure or
function presented throughout this disclosure. Rather, these
aspects are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the disclosure to
those skilled in the art. Based on the teachings herein one skilled
in the art should appreciate that the scope of the disclosure is
intended to cover any aspect of the disclosure disclosed herein,
whether implemented independently of or combined with any other
aspect of the disclosure. For example, an apparatus may be
implemented or a method may be practiced using any number of the
aspects set forth herein. In addition, the scope of the disclosure
is intended to cover such an apparatus or method which is practiced
using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim.
[0027] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any aspect described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other aspects.
[0028] Although particular aspects are described herein, many
variations and permutations of these aspects fall within the scope
of the disclosure. Although some benefits and advantages of the
preferred aspects are mentioned, the scope of the disclosure is not
intended to be limited to particular benefits, uses, or objectives.
Rather, aspects of the disclosure are intended to be broadly
applicable to different wireless technologies, system
configurations, networks, and transmission protocols, some of which
are illustrated by way of example in the figures and in the
following description of the preferred aspects. The detailed
description and drawings are merely illustrative of the disclosure
rather than limiting, the scope of the disclosure being defined by
the appended claims and equivalents thereof.
An Example Wireless Communication System
[0029] The techniques described herein may be used for various
wireless communication networks such as Orthogonal Frequency
Division Multiplexing (OFDM) networks, Time Division Multiple
Access (TDMA) networks, Frequency Division Multiple Access (FDMA)
networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA
(SC-FDMA) networks, Code Division Multiple Access (CDMA) networks,
etc. The terms "networks" and "systems" are often used
interchangeably. A CDMA network may implement a radio technology
such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc.
UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR).
CDMA2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network
may implement a radio technology such as Global System for Mobile
Communications (GSM). An OFDMA network may implement a radio
technology such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16
(e.g., WiMAX (Worldwide Interoperability for Microwave Access)),
IEEE 802.20, Flash-OFDM.RTM., etc. UTRA, E-UTRA, and GSM are part
of Universal Mobile Telecommunication System (UMTS). Long Term
Evolution (LTE) and Long Term Evolution Advanced (LTE-A) are
upcoming releases of UMTS that use E-UTRA. UTRA, E-UTRA, GSM, UMTS
and LTE are described in documents from an organization named "3rd
Generation Partnership Project" (3GPP). CDMA2000 is described in
documents from an organization named "3rd Generation Partnership
Project 2" (3GPP2). CDMA2000 is described in documents from an
organization named "3rd Generation Partnership Project 2" (3GPP2).
These various radio technologies and standards are known in the
art. For clarity, certain aspects of the techniques are described
below for LTE and LTE-A.
[0030] The teachings herein may be incorporated into (e.g.,
implemented within or performed by) a variety of wired or wireless
apparatuses (e.g., nodes). In some aspects a node comprises a
wireless node. Such wireless node may provide, for example,
connectivity for or to a network (e.g., a wide area network such as
the Internet or a cellular network) via a wired or wireless
communication link. In some aspects, a wireless node implemented in
accordance with the teachings herein may comprise an access point
or an access terminal.
[0031] An access point ("AP") may comprise, be implemented as, or
known as NodeB, Radio Network Controller ("RNC"), eNodeB, Base
Station Controller ("BSC"), Base Transceiver Station ("BTS"), Base
Station ("BS"), Transceiver Function ("TF"), Radio Router, Radio
Transceiver, Basic Service Set ("BSS"), Extended Service Set
("ESS"), Radio Base Station ("RBS"), or some other terminology. In
some implementations an access point may comprise a set top box
kiosk, a media center, or any other suitable device that is
configured to communicate via a wireless or wired medium.
[0032] An access terminal ("AT") may comprise, be implemented as,
or known as an access terminal, a subscriber station, a subscriber
unit, a mobile station, a remote station, a remote terminal, a user
terminal, a user agent, a user device, user equipment, a user
station, or some other terminology. In some implementations an
access terminal may comprise a cellular telephone, a cordless
telephone, a Session Initiation Protocol ("SIP") phone, a wireless
local loop ("WLL") station, a personal digital assistant ("PDA"), a
handheld device having wireless connection capability, a Station
("STA"), or some other suitable processing device connected to a
wireless modem. Accordingly, one or more aspects taught herein may
be incorporated into a phone (e.g., a cellular phone or smart
phone), a computer (e.g., a laptop), a portable communication
device, a portable computing device (e.g., a personal data
assistant), a tablet, an entertainment device (e.g., a music or
video device, or a satellite radio), a television display, a
flip-cam, a security video camera, a digital video recorder (DVR),
a global positioning system device, or any other suitable device
that is configured to communicate via a wireless or wired
medium.
[0033] Referring to FIG. 1, a multiple access wireless
communication system according to one aspect is illustrated. In an
aspect of the present disclosure, the wireless communication system
from FIG. 1 may be a wireless mobile broadband system based on
Orthogonal Frequency Division Multiplexing (OFDM). An access point
100 (AP) may include multiple antenna groups, one group including
antennas 104 and 106, another group including antennas 108 and 110,
and an additional group including antennas 112 and 114. In FIG. 1,
only two antennas are shown for each antenna group, however, more
or fewer antennas may be utilized for each antenna group. Access
terminal 116 (AT) may be in communication with antennas 112 and
114, where antennas 112 and 114 transmit information to access
terminal 116 over forward link 120 and receive information from
access terminal 116 over reverse link 118. Access terminal 122 may
be in communication with antennas 106 and 108, where antennas 106
and 108 transmit information to access terminal 122 over forward
link 126 and receive information from access terminal 122 over
reverse link 124. In a FDD system, communication links 118, 120,
124 and 126 may use different frequency for communication. For
example, forward link 120 may use a different frequency then that
used by reverse link 118.
[0034] Each group of antennas and/or the area in which they are
designed to communicate is often referred to as a sector of the
access point. In one aspect of the present disclosure each antenna
group may be designed to communicate to access terminals in a
sector of the areas covered by access point 100.
[0035] In communication over forward links 120 and 126, the
transmitting antennas of access point 100 may utilize beamforming
in order to improve the signal-to-noise ratio of forward links for
the different access terminals 116 and 122. Also, an access point
using beamforming to transmit to access terminals scattered
randomly through its coverage causes less interference to access
terminals in neighboring cells than an access point transmitting
through a single antenna to all its access terminals.
[0036] FIG. 2 illustrates a block diagram of an aspect of a
transmitter system 210 (e.g., also known as the access point) and a
receiver system 250 (e.g., also known as the access terminal) in a
wireless communications system, for example, a MIMO system 200. At
the transmitter system 210, traffic data for a number of data
streams is provided from a data source 212 to a transmit (TX) data
processor 214.
[0037] In one aspect of the present disclosure, each data stream
may be transmitted over a respective transmit antenna. TX data
processor 214 formats, codes, and interleaves the traffic data for
each data stream based on a particular coding scheme selected for
that data stream to provide coded data.
[0038] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data is typically a
known data pattern that is processed in a known manner and may be
used at the receiver system to estimate the channel response. The
multiplexed pilot and coded data for each data stream is then
modulated (i.e., symbol mapped) based on a particular modulation
scheme (e.g., BPSK, QPSK, m-QPSK, or m-QAM) selected for that data
stream to provide modulation symbols. The data rate, coding, and
modulation for each data stream may be determined by instructions
performed by processor 230.
[0039] The modulation symbols for all data streams are then
provided to a TX MIMO processor 220, which may further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 220 then
provides N.sub.T modulation symbol streams to N.sub.T transmitters
(TMTR) 222a through 222t. In certain aspects of the present
disclosure, TX MIMO processor 220 applies beamforming weights to
the symbols of the data streams and to the antenna from which the
symbol is being transmitted.
[0040] Each transmitter 222 receives and processes a respective
symbol stream to provide one or more analog signals, and further
conditions (e.g., amplifies, filters, and upconverts) the analog
signals to provide a modulated signal suitable for transmission
over the MIMO channel. N.sub.T modulated signals from transmitters
222a through 222t are then transmitted from N.sub.T antennas 224a
through 224t, respectively.
[0041] At receiver system 250, the transmitted modulated signals
may be received by N.sub.R antennas 252a through 252r and the
received signal from each antenna 252 may be provided to a
respective receiver (RCVR) 254a through 254r. Each receiver 254 may
condition (e.g., filters, amplifies, and downconverts) a respective
received signal, digitize the conditioned signal to provide
samples, and further process the samples to provide a corresponding
"received" symbol stream.
[0042] An RX data processor 260 then receives and processes the
N.sub.R received symbol streams from N.sub.R receivers 254 based on
a particular receiver processing technique to provide N.sub.T
"detected" symbol streams. The RX data processor 260 then
demodulates, deinterleaves, and decodes each detected symbol stream
to recover the traffic data for the data stream. The processing by
RX data processor 260 may be complementary to that performed by TX
MIMO processor 220 and TX data processor 214 at transmitter system
210.
[0043] A processor 270 periodically determines which pre-coding
matrix to use. Processor 270 formulates a reverse link message
comprising a matrix index portion and a rank value portion. The
reverse link message may comprise various types of information
regarding the communication link and/or the received data stream.
The reverse link message is then processed by a TX data processor
238, which also receives traffic data for a number of data streams
from a data source 236, modulated by a modulator 280, conditioned
by transmitters 254a through 254r, and transmitted back to
transmitter system 210.
[0044] At transmitter system 210, the modulated signals from
receiver system 250 are received by antennas 224, conditioned by
receivers 222, demodulated by a demodulator 240, and processed by a
RX data processor 242 to extract the reserve link message
transmitted by the receiver system 250. Processor 230 then
determines which pre-coding matrix to use for determining the
beamforming weights, and then processes the extracted message.
[0045] FIG. 3 illustrates various components that may be utilized
in a wireless device 302 that may be employed within the wireless
communication system from FIG. 1. The wireless device 302 is an
example of a device that may be configured to implement the various
methods described herein. The wireless device 302 may be an access
point 100 from FIG. 1 or any of access terminals 116, 122.
[0046] The wireless device 302 may include a processor 304 which
controls operation of the wireless device 302. The processor 304
may also be referred to as a central processing unit (CPU). Memory
306, which may include both read-only memory (ROM) and random
access memory (RAM), provides instructions and data to the
processor 304. A portion of the memory 306 may also include
non-volatile random access memory (NVRAM). The processor 304
typically performs logical and arithmetic operations based on
program instructions stored within the memory 306. The instructions
in the memory 306 may be executable to implement the methods
described herein.
[0047] The wireless device 302 may also include a housing 308 that
may include a transmitter 310 and a receiver 312 to allow
transmission and reception of data between the wireless device 302
and a remote location. The transmitter 310 and receiver 312 may be
combined into a transceiver 314. A single or a plurality of
transmit antennas 316 may be attached to the housing 308 and
electrically coupled to the transceiver 314. The wireless device
302 may also include (not shown) multiple transmitters, multiple
receivers, and multiple transceivers.
[0048] The wireless device 302 may also include a signal detector
318 that may be used in an effort to detect and quantify the level
of signals received by the transceiver 314. The signal detector 318
may detect such signals as total energy, energy per subcarrier per
symbol, power spectral density and other signals. The wireless
device 302 may also include a digital signal processor (DSP) 320
for use in processing signals.
[0049] Additionally, the wireless device may also include an
encoder 322 for use in encoding signals for transmission and a
decoder 324 for use in decoding received signals.
[0050] The various components of the wireless device 302 may be
coupled together by a bus system 326, which may include a power
bus, a control signal bus, and a status signal bus in addition to a
data bus.
[0051] FIG. 4 is a simplified block diagram illustrating an
encoder, in accordance with certain aspects of the present
disclosure. According to certain aspects, the encoder 322
illustrated in FIG. 3 may comprise the encoder illustrated in FIG.
4. FIG. 4 illustrates a portion of a radio frequency (RF) modem 404
that may be configured to provide an encoded message for wireless
transmission. In one example, an encoder 406 in a base station
(e.g., BS 110 and/or 210) (or an access terminal on the reverse
path) receives a message 402 for transmission. The message 402 may
contain data and/or encoded voice or other content directed to the
receiving device. The encoder 406 encodes the message using a
suitable modulation and coding scheme (MCS), typically selected
based on a configuration defined by the base station 110/210 or
another network entity. In some cases, the encoder 406 may encode
the message using techniques described below (e.g., by using a
convolutional code). An encoded bitstream 408 produced by the
encoder 406 may then be provided to a mapper 410 that generates a
sequence of Tx symbols 412 that are modulated, amplified and
otherwise processed by Tx chain 414 to produce an RF signal 416 for
transmission through antenna 418.
[0052] FIG. 5 is a simplified block diagram illustrating a decoder,
in accordance with certain aspects of the present disclosure.
According to certain aspects, the decoder 324 illustrated in FIG. 3
may comprise the decoder illustrated in FIG. 5. FIG. 5 illustrates
a portion of a RF modem 510 that may be configured to receive and
decode a wirelessly transmitted signal including an encoded message
(e.g., a message encoded using a convolutional code as described
below). In various examples, the modem 510 receiving the signal may
reside at the access terminal, at the base station, or at any other
suitable apparatus or means for carrying out the described
functions. An antenna 502 provides an RF signal 418 (i.e., the RF
signal produced in FIG. 4) to an access terminal (e.g., access
terminal 116, 118, and/or 250). An RF chain 506 processes and
demodulates the RF signal 418 and may provide a sequence of symbols
508 to a demapper 512, which produces a bitstream 514
representative of the encoded message.
[0053] A decoder 516 may then be used to decode m-bit information
strings from a bitstream that has been encoded using a coding
scheme (e.g., a convolutional code). The decoder 516 may comprise a
Viterbi decoder, an algebraic decoder, a butterfly decoder, or
another suitable decoder. In one example, a Viterbi decoder employs
the well-known Viterbi algorithm to find the most likely sequence
of signaling states (the Viterbi path) that corresponds to a
received bitstream 514. The bitstream 514 may be decoded based on a
statistical analysis of LLRs calculated for the bitstream 514. In
one example, a Viterbi decoder may compare and select the correct
Viterbi path that defines a sequence of signaling states using a
likelihood ratio test to generate LLRs from the bitstream 514.
Likelihood ratios can be used to statistically compare the fit of a
plurality of candidate Viterbi paths using a likelihood ratio test
that compares the logarithm of a likelihood ratio for each
candidate Viterbi path (i.e. the LLR) to determine which path is
more likely to account for the sequence of symbols that produced
the bitstream 514. The decoder 516 may then decode the bitstream
514 based on the LLRs to determine the message 518 containing data
and/or encoded voice or other content transmitted from the base
station (e.g., BS 110 and/or 210). The decoder may decode the
bitsteam 514 in accordance with aspects of the present disclosure
presented below.
Example Hybrid Automatic Repeat Request (Harq) Feedback Bits for
Polar Codes
[0054] Aspects of the present disclosure are generally directed to
an efficient design of hybrid automatic repeat request (HARQ)
feedback bits for Polar codes by considering the sorting of
channels based on the bit-error probability.
[0055] Polar codes were invented in 2007 and are the first codes
with an explicit construction to provably achieve the channel
capacity for symmetric binary-input discrete memoryless channels.
The capacity can be achieved with a simple successive cancellation
(SC) decoder. Polar codes and low-density parity check (LDPC) codes
are two competitive candidates for 5G channel coding.
[0056] Polar codes are block codes. The generate matrices of Polar
codes are the submatrices of Hadamard matrices. To construct Polar
codes, the rows of the Hadamard matrices corresponding to the good
channels (e.g., having low bit-error probability) may be selected
for information bits. The bad channels (e.g., having high bit-error
probability) may be used for frozen bits with fixed value of zeros.
In a practical system, density evolution or Gaussian approximation
is generally used to determine the bit-error probability of each
channel. The bit-error probabilities of all the channels may be
sorted. If N information bits are desired, the best N channels
(with low bit-error probability) are selected for information bits
while the remaining channels are designated for frozen bits. If the
information block are divided into several equal sub-blocks, the
block error rate of the sub-blocks close to the best channel should
be lower than that close to the worst channel. HARQ scheme is
widely used in wireless communication system to improve
transmission efficiency. HARQ scheme generally includes the
retransmission of coded blocks that are not decoded correctly at a
receiver. Aspects of the present disclosure use this property for
an efficient design of HARQ feedback.
[0057] FIG. 6A illustrates an example structure 600 of coded blocks
of a signal transmission. A large transport block (TB) may be
segmented into several small sub-blocks (e.g., if the TB size is
larger than 6144 bits). In some cases, there may be a single cyclic
redundancy check (CRC) attached for all the bits in the transport
block. The CRC may be used to determine if the TB is decoded
correctly. The HARQ feedback bit is generated based on the decoding
result.
[0058] FIG. 6B illustrates an example structure 602 of HARQ
feedback bits. As illustrated in FIG. 6A, a TB may be segmented
into several blocks and each block may be encoded as one codeword.
A CRC may be attached for each block and may be used for early
termination. In this case, only a single bit may be used for
acknowledgement/no-acknowledgement (ACK/NACK). That is, a NACK may
be obtained by a transmitter for an entire block even if only one
sub-block was not decoded correctly at the receiver. In this case,
all the sub-blocks may be retransmitted again as the transmitter
would not be able to know which sub-blocks were not decoded
correctly, resulting in wasted resources. Moreover, it may be
difficult for the receiver to feed back the cyclic redundancy check
(CRC) result for each block to the transmitter because of the large
number of ACK/NACK bits.
[0059] In 5G wireless communication systems, the desired data rate
is high. To provide high data rate, a large size TB (e.g., with up
to one million bits) may be implemented. If all the coded blocks
are retransmitted when majority of them are decoded correctly, a
significant amount of resources may be wasted.
[0060] Aspects of the present disclosures provide a more efficient
HARQ feedback process. For example, polar codes may be used to
divide coded blocks into several groups and a bit may be used to
indicate the overall decoding results of each group. This way,
multiple feedback bits may be used to signal the decoding results
of the groups. If the blocks in a group are decoded correctly, that
group may not be retransmitted, saving resources.
[0061] FIG. 7 illustrates example operations 700 for wireless
communications. According to certain aspects, operations 700 may be
performed by a wireless transmission device (e.g., wireless device
302).
[0062] Operations 700 begin at 702 by obtaining a payload to be
transmitted. At 704, the wireless transmission device partitions
the payload into a plurality of blocks. At 706, the wireless
transmission device partitions each block of the plurality of
blocks into a plurality of sections, and at 708, derives redundancy
check information for each section of the plurality of sections. At
710, the wireless transmission device generates a plurality of
codewords, each comprising a block of the plurality of blocks and
the redundancy check information for each section of the block,
wherein a location of each of the sections in the codewords is
determined based on an error rate corresponding to each of the
sections.
[0063] FIG. 8 illustrates example operations 800 for wireless
communications. According to certain aspects, operations 800 may be
performed by a wireless reception device (e.g., wireless device
302). According to certain aspects, operations 800 may be
complimentary to the operations 700. For example, operations 700
may be performed by wireless transmission device for generating
(and transmitting) a codeword and operations 800 may be performed
by a wireless reception device for receiving and decoding the
codeword.
[0064] Operations 800 begin at 802 by receiving a plurality of
codewords, each comprising a plurality of blocks, wherein each of
the plurality of blocks comprise a plurality of sections and
redundancy check information for each section of the plurality of
sections, wherein a location of each of the plurality of sections
of each block is determined based on an error rate corresponding to
each of the plurality of sections of each block. At 804, the
wireless reception device decodes the plurality of sections of each
block. At 806, the wireless reception device verifies whether the
plurality of sections of each block were properly decoded based on
the redundancy check information for each of the decoded sections.
At 808, an indication of whether the plurality of sections of each
block was properly decoded is transmitted based on the
verification.
[0065] FIG. 9A illustrates an example structure 900 of the coded
blocks segmented into two groups, in accordance with certain
aspects of the present disclosure. As presented above, if a TB size
is larger than a threshold (for example, 8000 bits), the TB may be
segmented into several blocks and each block may be encoded as one
codeword. A CRC may be attached for each block, as illustrated.
There are several purposes for the CRC. For example, the CRC can be
used to determine if the corresponding block is decoded correctly.
Moreover, the CRC may be used for CRC-aided successive cancellation
list (CA-SCL) decoding to provide better performance.
[0066] In each codeword, all the bit-channels may be sorted from
best channel to worst channel according to bit-error probability.
In some aspects, the bit-error probability may be obtained by
density evolution or Gaussian approximation. For example, the
information bits and CRC may be divided into two groups A and B.
Group A may have a low block error rate as compared to group B.
Each codeword may include the CRC bits for group A, data for group
A, the CRC bits for group B, and the data for group B. Frozen bits
may be allocated to one or more channels having the lowest
bit-error probability (worst channels). Therefore, the block error
rate of group A may be lower than the error rate of group B. Each
coded block may be obtained by bit-reversal permutation and
encoding.
[0067] FIG. 9B illustrates an example structure 902 of HARQ
feedback bits (e.g., for Polar codes) for coded blocks segmented
into two block groups, in accordance with certain aspects of the
present disclosure. As illustrated, two feedback bits may be used
to indicate four possible cases. The result of group A or group B
may be indicated separately. Thus, it is possible for a transmitter
to choose an efficient way to realize HARQ. For example, if the
transmitter receives feedback bits as "10", this implies that the
codewords in group A are decoded correctly. In this case, the
transmitter will prepare the retransmission based on group B
without considering group A. For HARQ with chase combining, only
the codewords in group B is retransmitted. Only half of the
resources may be used as compared to the existing design of
feedback bits. For HARQ with increment redundancy, this also allows
for a more efficient way for retransmission in the case where group
A is decoded correctly.
[0068] FIG. 10A illustrates an example structure 1000 of the coded
blocks segmented into three groups, in accordance with certain
aspects of the present disclosure. There is a CRC attached for all
the bits in the transport block. The CRC is used to determine if
the TB is decoded correctly. The HARQ feedback bits are generated
based on the decoding results of the TB. If the TB size is larger
than a threshold (e.g., 8000 bits), the TB may be segmented into
several blocks and each block may be encoded as one codeword, as
illustrated. A CRC is attached for each block.
[0069] As presented above, there may be two purposes for the CRC.
First, the CRC can be used to determine if the corresponding block
is decoded correctly. Second, the CRC may be used for CRC-aided
successive cancellation list (CA-SCL) decoding to provide better
performance. In each codeword, all the bit-channels may be sorted
from best channel to worst channel according to the bit-error
probability. The bit-error probability may be obtained by density
evolution or Gaussian approximation.
[0070] In this case, the information bits and CRC attached are
divided into three groups: group A with lowest block error rate,
group B with low block error rate and group C with high block error
rate. Each codeword may include CRC bits for group A, data for
group A, CRC bits for group B, data for group B, CRC bits for group
C, data for group C. Moreover, frozen bits may be allocated to one
or more channels having the lowest bit-error probability (worst
channels). Therefore, the block error rate of group A may be lower
than that of group B and the block error rate of group B may be
lower than that of group C. Each coded block is obtained by
bit-reversal permutation and encoding.
[0071] FIG. 10B illustrates an example structure 1002 of HARQ
feedback bits (e.g., for Polar codes) for coded blocks segmented
into three block groups, in accordance with certain aspects of the
present disclosure. For three groups, three bits may be used for
HARQ feedback, each bit corresponding to one of the three groups.
However, aspects of the present disclosure may use two feedback
bits instead of three. That is, the number of feedback bits can be
reduced by considering the relationship among the block error rates
of group A, group B, and group C. Since block error rate of group A
is lower than that of group B and block error rate of B is lower
than that of group C, the probability that group A is not decoded
correctly while group B or group C is decoded correctly is low.
Similarly, the probability that group B is not decoded correctly
while group C is decoded correctly is low.
[0072] Therefore, aspects of the present disclosure provide an
efficient design of HARQ feedback using two bits for three groups
by eliminating the cases with low probability. For example, if the
transmitter receives feedback bits "10", this implies that the
codewords in group A and group B are decoded correctly. The
transmitter will prepare the retransmission based on group C
without considering group A and group B. For HARQ with chase
combining, only the codewords in group C may be retransmitted. In
this case, only one third of the resources may be used as compared
to the existing design of feedback bits. For HARQ with increment
redundancy, it is also easy to find an efficient way for
retransmission on condition that the group A and group B are
decoded correctly. While examples provided herein have described
HARQ feedback with codewords segmented into two groups and three
groups to facilitate understanding, the techniques provided herein
may be applied to codewords segmented into any number of
groups.
[0073] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0074] Those of skill in the art would understand that information
and signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0075] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrated circuit
(ASIC), or processor.
[0076] For example, means for processing, means for generating,
means for obtaining, means for partitioning, means for determining,
means for deriving, means for merging, means for verifying, means
for concatenating, means for interleaving, means for decoding, and
means for encoding may comprise a processing system, which may
include one or more processors, such as the TX data processor 214,
the processor 230, and/or the RX data processor 242 of the access
point 210 illustrated in FIG. 2 or the TX data processor 238, the
processor 270, and/or the RX data processor 260 of the user
equipment 250 illustrated in FIG. 2. Additionally, means for
transmitting and means for receiving may comprise a TMTR/RCVR 224
of the access point 210 or a TMTR/RCVR 252 of the user equipment
250.
[0077] According to certain aspects, such means may be implemented
by processing systems configured to perform the corresponding
functions by implementing various algorithms (e.g., in hardware or
by executing software instructions) described above.
[0078] Those of skill would further appreciate that the various
illustrative logical blocks, modules, circuits, and algorithm steps
described in connection with the disclosure herein may be
implemented as electronic hardware, computer software, or
combinations of both. To clearly illustrate this interchangeability
of hardware and software, various illustrative components, blocks,
modules, circuits, and steps have been described above generally in
terms of their functionality. Whether such functionality is
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall system.
Skilled artisans may implement the described functionality in
varying ways for each particular application, but such
implementation decisions should not be interpreted as causing a
departure from the scope of the present disclosure.
[0079] The various illustrative logical blocks, modules, and
circuits described in connection with the disclosure herein may be
implemented or performed with a general-purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0080] The steps of a method or algorithm described in connection
with the disclosure herein may be embodied directly in hardware, in
a software module executed by a processor, or in a combination of
the two. A software module may reside in RAM memory, flash memory,
ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a
removable disk, a CD-ROM, or any other form of storage medium known
in the art. An exemplary storage medium is coupled to the processor
such that the processor can read information from, and/or write
information to, the storage medium. In the alternative, the storage
medium may be integral to the processor. The processor and the
storage medium may reside in an ASIC. The ASIC may reside in a user
terminal. In the alternative, the processor and the storage medium
may reside as discrete components in a user terminal.
[0081] In one or more exemplary embodiments, the functions
described may be implemented in hardware, software, firmware, or
any combination thereof. If implemented in software, the functions
may be stored on or transmitted over as one or more instructions or
code on a computer-readable medium. Computer-readable media
includes both computer storage media and communication media
including any medium that facilitates transfer of a computer
program from one place to another. A storage media may be any
available media that can be accessed by a general purpose or
special purpose computer. By way of example, and not limitation,
such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM
or other optical disk storage, magnetic disk storage or other
magnetic storage devices, or any other medium that can be used to
carry or store desired program code means in the form of
instructions or data structures and that can be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, includes compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and BLU-RAY.RTM.
media disc where disks usually reproduce data magnetically, while
discs reproduce data optically with lasers. Combinations of the
above should also be included within the scope of computer-readable
media.
[0082] As used herein, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
[0083] The previous description of the disclosure is provided to
enable any person skilled in the art to make or use the disclosure.
Various modifications to the disclosure will be readily apparent to
those skilled in the art, and the generic principles defined herein
may be applied to other variations without departing from the
spirit or scope of the disclosure. Thus, the disclosure is not
intended to be limited to the examples and designs described
herein, but is to be accorded the widest scope consistent with the
principles and novel features disclosed herein.
* * * * *