U.S. patent application number 16/221150 was filed with the patent office on 2020-06-18 for space time block codes for semi-orthogonal multi-access based wlan systems.
This patent application is currently assigned to HUAWEI TECHNOLOGIES CO., LTD.. The applicant listed for this patent is Jia BAYESTEH JIA. Invention is credited to Osama ABOUL-MAGD, Kwok Shum AU, Alireza BAYESTEH, Jia JIA, Jung Hoon SUH.
Application Number | 20200195381 16/221150 |
Document ID | / |
Family ID | 71071256 |
Filed Date | 2020-06-18 |
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United States Patent
Application |
20200195381 |
Kind Code |
A1 |
JIA; Jia ; et al. |
June 18, 2020 |
SPACE TIME BLOCK CODES FOR SEMI-ORTHOGONAL MULTI-ACCESS BASED WLAN
SYSTEMS
Abstract
The disclosed systems, structures, and methods are directed to a
wireless local area network (WLAN) transmission architecture and
transmitting methodology that combines space-time block code (STBC)
encoding techniques with semi-orthogonal multiple access (SOMA)
schemes to improve throughput rate performance for lower signal
strength data. The transmission architecture and method includes a
data processing module that is configured to digitally process and
format data produced by two wireless stations. A SOMA constellation
quadrature encoding module operates to apply quadrature-based
modulation to the processed data and map the data to a modulation
constellation based on data signal strength and data bit
reliability. An STBC encoding module is configured to block encode
the SOMA modulated data with orthogonal codes to produce STBC-based
SOMA-symbol data having time and space diversity properties that
improve throughput performance at lower signal strength levels.
Inventors: |
JIA; Jia; (Shenzhen, CN)
; BAYESTEH; Alireza; (Kanata, CA) ; SUH; Jung
Hoon; (Ottawa, CA) ; ABOUL-MAGD; Osama;
(Kanata, CA) ; AU; Kwok Shum; (Ottawa,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JIA; Jia
BAYESTEH; Alireza
SUH; Jung Hoon
ABOUL-MAGD; Osama
AU; Kwok Shum |
Shenzhen
Kanata
Ottawa
Kanata
Ottawa |
|
CN
CA
CA
CA
CA |
|
|
Assignee: |
HUAWEI TECHNOLOGIES CO.,
LTD.
Shenzhen
CN
|
Family ID: |
71071256 |
Appl. No.: |
16/221150 |
Filed: |
December 14, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/0059 20130101;
H04L 1/0612 20130101; H04L 1/0643 20130101; H04B 17/336 20150115;
H04L 27/3494 20130101; H04L 1/0668 20130101; H04L 1/0071
20130101 |
International
Class: |
H04L 1/06 20060101
H04L001/06; H04L 27/34 20060101 H04L027/34; H04L 1/00 20060101
H04L001/00 |
Claims
1. A wireless local area network (WLAN) communication device,
comprising: a data processing module configured to digitally
process first data for a first wireless station (STA) and second
data for a second wireless station (STA); a space-time block code
(STBC) encoding module operative to receive and encode the
processed first data to produce first orthogonal block-encoded
symbol data; a semi-orthogonal multiple access (SOMA) encoding
module configured to apply quadrature-based modulation
constellation mapping to the first orthogonal block-encoded symbol
data and to the processed second data, to produce STBC-based
SOMA-symbol data; and a communication module configured to transmit
the STBC-based SOMA-symbol data to the first and second STAs.
2. The WLAN communication device of claim 1, wherein the STBC
encoding module operates to digitally process the first data by
scrambling the data, binary convolutionally encoding the scrambled
data, and interleaving the binary convolutionally-encoded data.
3. The WLAN communication device of claim 1, wherein the STBC
encoding module operates to block encode the processed first data
with two orthogonal symbols within two consecutive time
intervals.
4. The WLAN communication device of claim 1, wherein the SOMA
encoding module is configured to apply quadrature amplitude
modulation (QAM) to the first orthogonal block-encoded symbol data
and the processed second data.
5. The WLAN communication device of claim 1, wherein the first data
have a lower signal-to-noise ratio (SNR) level than the second
data.
6. The WLAN communication device of claim 5, wherein the SOMA
encoding module operates to assign and map most reliable bits
(MRBs) to the first data and assign and map least reliable bits
(LRBs) to the second data.
7. The WLAN communication device of claim 1, wherein an indication
of the STBC-based SOMA data symbol format is included in a signal
(SIG) field of a communicated data packet frame structure.
8. The WLAN communication device of claim 7, wherein the indication
of the STBC-based SOMA data symbol format is included in an
Extremely High Throughput (EHT) SIG field of the communicated data
packet frame structure.
9. The WLAN communication device of claim 1, wherein STBC encoding
is applied only to the processed first data of the first STA.
10. The WLAN communication device of claim 1, wherein STBC encoding
is applied to the processed second data.
11. A method for communicating data in a wireless local area
network (WLAN), comprising: digitally processing first data for a
first wireless station (STA) and second data for a second wireless
station (STA); encoding the processed first data of the first STA
with a space-time block code (STBC) to produce first orthogonal
block-encoded symbol data; applying semi-orthogonal multiple access
(SOMA) encoding configured to apply quadrature-based modulation
constellation mapping to the first orthogonal block-encoded symbol
data and to the processed second data to produce STBC-based
SOMA-symbol data; and transmitting the STBC-based SOMA-symbol data
to the first and second STAs.
12. The WLAN communication method of claim 11 wherein the digitally
processing of the first data includes digitally scrambling the
data, binary convolutionally encoding the scrambled data, and
interleaving the binary convolutionally-encoded data.
13. The WLAN communication method of claim 11, wherein the STBC
encoding includes block encoding the processed first data with two
orthogonal symbols within two consecutive time intervals.
14. The WLAN communication method of claim 11, wherein the SOMA
encoding includes applying quadrature amplitude modulation (QAM) to
the first orthogonal block-encoded symbol data and the processed
second data.
15. The WLAN communication method of claim 11, wherein the first
data have a lower signal-to-noise ratio (SNR) level than the second
data.
16. The WLAN communication method of claim 11, wherein the SOMA
encoding assigns and maps most reliable bits (MRBs) to the first
data and assigns and maps least reliable bits (LRBs) to the second
data.
17. The WLAN communication method of claim 11, wherein an
indication of the STBC-based SOMA data symbol format is included in
a signal (SIG) field of a communicated data packet frame
structure.
18. The WLAN communication method of claim 17, wherein the
indication of the STBC-based SOMA data symbol format is included in
an Extremely High Throughput (EHT) SIG field of the communicated
data packet frame structure.
19. The WLAN communication method of claim 11, wherein the STBC
encoding is applied only to the processed first data.
20. The WLAN communication method of claim 11, wherein the STBC
encoding is applied to the processed second data.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the field of
wireless local area networks (WLANs) and, in particular, to systems
and methods directed to applying space-time block codes (STBC) to
semi-orthogonal multi-access (SOMA)-based WLAN architectures to
improve throughput of lower signal-to-noise (SNR) signals.
BACKGROUND
[0002] Various proposals have been presented regarding the
improvement of service capabilities for existing and
next-generation wireless communication systems, including wireless
local area network (WLAN) platforms in accordance with the
Institute of Electrical and Electronics Engineers (IEEE) 802.11
standards.
[0003] Some improvements call for the realization of higher data
rates and increased channel throughput and in an effort to address
these goals, certain schemes provide for the increased
implementation of multiple-input, multiple-output (MIMO) and
massive-MIMO (M-MIMO) receiver architectures for WLAN
communications. However, MIMO/M-MIMO receivers may, under certain
conditions, exhibit limitations regarding the reliable support of
higher data rates and increased channel throughput.
[0004] To this end, the use of semi-orthogonal multiple access
(SOMA) schemes in conjunction with MIMO-based receiver
architectures has been proposed to address the reliability issues
of WLAN high throughput processing. Such MIMO-based SOMA schemes
have demonstrated meaningful throughput improvement at higher
signal-to-noise ratio (SNR) levels.
SUMMARY
[0005] An object of the present disclosure is to provide a wireless
local area network (WLAN) transmission architecture that combines
space-time block code (STBC) encoding techniques with
semi-orthogonal multiple access (SOMA) schemes to improve
throughput rate performance for lower signal strength data. The
transmission architecture includes a data processing module that is
configured to digitally process and format data produced by two
wireless stations. A space-time block code (STBC) encoding module
encodes the processed data with orthogonal block codes to produce
orthogonal block-encoded symbol data having time and space
diversity properties. A semi-orthogonal multiple access (SOMA)
encoding module operates to apply quadrature-based modulation
constellation mapping to the orthogonal block-encoded symbol data
and to the processed data, based on data signal strength and data
bit reliability, to produce STBC-based SOMA-symbol data.
[0006] In accordance with other aspects of the present disclosure,
there is provided a related methodology for transmitting data in a
wireless local area network (WLAN) that combines space-time block
code (STBC) encoding techniques with semi-orthogonal multiple
access (SOMA) schemes to improve throughput rate performance for
lower signal strength data. The transmitting method includes
digitally processing and formatting data generated by a first and
second wireless station. The transmitting method then applies
space-time block code (STBC) to the processed data to produce
orthogonal block-encoded symbol data having time and space
diversity properties. The method further applies semi-orthogonal
multiple access (SOMA) encoding to the orthogonal block-encoded
symbol data and to the processed data, the SOMA encoding providing
quadrature-based modulation constellation mapping to the orthogonal
block-encoded symbol data and to the processed data, based on data
signal strength and data bit reliability, to produce STBC-based
SOMA-symbol data.
[0007] In accordance with other objects of the present disclosure,
there is provided an alternative wireless local area network (WLAN)
transmission architecture that combines space-time block code
(STBC) encoding techniques with semi-orthogonal multiple access
(SOMA) schemes to improve throughput rate performance for lower
signal strength data. In this alternative embodiment, a data
processing module configured to digitally process and format data
generated by a first and second wireless station. A SOMA encoding
module operates to apply quadrature-based modulation constellation
mapping to the processed data, based on data signal strength and
data bit reliability, to produce SOMA modulated symbol data. A
space-time block code (STBC) encoding module then operates to
encode the SOMA modulated symbol data with orthogonal block codes
to produce STBC-based SOMA-symbol data having time and space
diversity properties.
[0008] Moreover, in a related embodiment, the disclosed embodiments
provide for a methodology for transmitting data in a wireless local
area network (WLAN) that combines space-time block code (STBC)
encoding techniques with semi-orthogonal multiple access (SOMA)
schemes to improve throughput rate performance for lower signal
strength data. The transmitting method includes digitally
processing and formatting the data produced by two wireless
stations. The transmitting method then applies SOMA constellation
quadrature encoding to the processed data and maps the data to a
modulation constellation based on data signal strength and data bit
reliability. The method further applies STBC encoding to block
encode the SOMA modulated data with orthogonal codes to produce
STBC-based SOMA-symbol data having time and space diversity
properties that improve throughput performance at lower signal
strength levels.
BRIEF DESCRIPTION OF THE FIGURES
[0009] The features and advantages of the present disclosure will
become apparent from the following detailed description, taken in
combination with the appended drawings, in which:
[0010] FIG. 1A depicts a high-level diagram of a representative
WLAN environment;
[0011] FIG. 1B depicts a high-level functional block diagram of a
representative MIMO-based SOMA transmitter architecture;
[0012] FIG. 2A depicts a high-level diagram of STBC encoding of
modulated data streams, in accordance with various embodiments of
the present disclosure;
[0013] FIG. 2B depicts a high-level diagram of STBC decoding of
modulated data streams, in accordance with various embodiments of
the present disclosure;
[0014] FIG. 3A depicts a high-level functional block diagram of an
STBC-based pre-SOMA scheme transmitting architecture, in accordance
with various embodiments of the present disclosure;
[0015] FIG. 3B depicts a high-level functional block diagram of an
STBC-based post-SOMA scheme transmitting architecture, in
accordance with various embodiments of the present disclosure;
[0016] FIG. 4A depicts a high-level flow diagram of an STBC-based
pre-SOMA scheme transmitting process, in accordance with various
embodiments of the present disclosure;
[0017] FIG. 4B depicts a high-level flow diagram of an STBC-based
post-SOMA scheme transmitting process, in accordance with various
embodiments of the present disclosure;
[0018] FIG. 5A illustrates relative packet error rates for
STBC-based and non STBC-based SOMA schemes, in accordance with
various embodiments of the present disclosure; and
[0019] FIG. 5B illustrates relative throughput results for
STBC-based and non STBC-based SOMA schemes, in accordance with
various embodiments of the present disclosure.
[0020] It is to be understood that throughout the appended drawings
and corresponding descriptions, like features are identified by
like reference characters. Furthermore, it is also to be understood
that the drawings and ensuing descriptions are intended for
illustrative purposes only and that such disclosures are not
intended to limit the scope of the claims.
DETAILED DESCRIPTION
[0021] As used herein, the term "about" or "approximately" refers
to a +/-10% variation from the nominal value. It is to be
understood that such a variation is always included in a given
value provided herein, whether or not it is specifically referred
to.
[0022] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the described embodiments
pertain.
WLAN Environment and MIMO-Based SOMA Scheme
[0023] FIG. 1A illustrates a high-level block diagram of a
representative WLAN environment 100. As illustrated, WLAN
environment 100 comprises a wireless access point (AP) 102
configured to wirelessly communicate with multiple wireless
stations STAs (STA0-STAn) 104-10n, in accordance with current and
next-generation IEEE 802.11 standards. AP 102 initiates such
communications by providing signaling information indicative of
communication schedule opportunities to STAs 104-10n. During the
scheduled communication session, STAs 104-10n may receive and
transmit data streams to and from AP 102.
[0024] It will be appreciated that in various wireless scenarios,
AP 102 may be characterized as a base station, evolved NodeB (eNB),
base station terminal etc., and wireless stations STAs 104-10n may
be characterized as mobile stations, user equipment, client
terminals, etc. Moreover, it will be understood that, although
depicted AP 102 is capable of communicating with multiple STAs
104-10n, for the purposes clarity and tractability, the following
descriptions will focus on communications between AP 102, a far
field-situated STA0 104, and a near field-situated STA1 106.
Furthermore, it will be assumed that, by virtue of its proximity to
AP 102, near field STA1 106 provides a stronger signal level (i.e.,
higher signal-to-noise ratio (SNR)) than the far-field STA0 104
signal to AP 102.
[0025] Given this context, FIG. 1B depicts a high-level functional
block diagram of a representative MIMO-based semi-orthogonal
multiple access (SOMA) transmitter architecture 150. By way of
review, the SOMA scheme exploits the notion that the weaker STA0
104 signal may not significantly interfere with the stronger STA1
106 signal. Therefore, during the processing of the stronger STA1
106 signal, the weaker STA0 104 signal is treated as an orthogonal
signal. Conversely, because the stronger STA1 106 signal may have
an interfering effect on the weaker STA0 104 signal, the SOMA
scheme treats the stronger STA1 106 signal as a non-orthogonal
signal when processing the weaker STA0 104 signal.
[0026] Moreover, in the SOMA scheme, each of the STA0 104 and STA1
106 are configured to output the same number of data streams (e.g.,
STA0: streams 1-j and STA1: streams 1-j). The data of each
corresponding data stream 1-j of STA0 104 and STA1 106 are grouped
together for QAM modulation constellation map processing.
[0027] That is, as shown in FIG. 1B, the data of the data stream 1
of far field STA0 104 is grouped with the data of the stream 1 of
near field STA1 106 and supplied to the SOMA QAM constellation
mapping unit 152-1. The same stream-based data grouping principle
is applied to data streams 2-j of STA0 104 and STA1 106, in which
the grouped data is correspondingly forwarded to SOMA QAM
constellation mapping units 152-2 . . . 152-j.
[0028] The SOMA QAM constellation mapping units 152-1 . . . 152-j
operate to assign and map the most reliable bits (MRBs) to the
lower-SNR data (i.e., far-field STA0 104 data), and assign and map
the least reliable bits (LRBs) to the higher-SNR data (i.e.,
near-field STA1 106 data), during QAM modulation processing. The
SOMA QAM constellation mapping units 152-1 . . . 152-j incorporate
bit combining and symbol mapping elements to assign the more
reliable bits to the lower SNR channel to increase the probability
of successful decoding. In contrast, the mapping units 152-1 . . .
152-j employ the bit combining and symbol mapping elements to
assign the less reliable bits to the higher SNR channel in view of
the likelihood of successful decoding due to the higher SNR.
[0029] Further details regarding SOMA-based QAM constellation
modulation and mapping are provided by co-assigned U.S. Pat. No.
9,866,364, entitled "System and Method for Semi-Orthogonal Multiple
Access", application Ser. No. 14/589,676, filed on Jan. 5, 2015 and
issued on Jan. 9, 2018, which is hereby incorporated herein by
reference.
[0030] The MIMO-based SOMA scheme described above has demonstrated
improved data throughput at higher SNR signal levels. However, at
lower SNR levels, there is little or no improvement in data
throughput.
STBC-Based SOMA Scheme
[0031] The various embodiments of the instant disclosure are
therefore directed to MIMO-based SOMA schemes that incorporate
space-time block codes (STBCs) to enhance the throughput of lower
signal-to-noise (SNR) WLAN signals. In keeping with the two STA
scenario noted above, the ensuing disclosures provide for an
STBC-based SOMA scheme that incorporates STBC block codes that may
be applied to either one or both of the STAs' SOMA modulated data.
In addition, an indication of the STBC-based SOMA implementation is
to be included in the packet data frame structure, such as in the
Extremely High Throughput (EHT) signal (SIG) field, to ensure
proper processing.
[0032] STBCs are orthogonal codes that may be used to block encode
wireless data. STBCs facilitate the transmission of numerous copies
of the block encoded data that can be distributed across multiple
spaced-apart antennas and across time to provide space and time
diversity gains. By virtue of the STBC orthogonality and diversity
properties, the various received versions of the encoded data may
be linearly decoded to provide reliable receipt of information
content.
[0033] FIG. 2A depicts the STBC encoding process 200 of modulated
data streams, in accordance with various embodiments of the present
disclosure. The encoding operations depicted by FIG. 2A illustrate
the application of STBC-encoding for two lower-SNR data streams 0
and 1 of far-field STA0 104. It will be understood, however, that
the described STBC-block encoding scheme may be applied to the data
streams of either STA0 104 or STA1 106 or to both, in accordance
with the concepts and principles embodied by the instant
disclosure.
[0034] FIG. 2A indicates that STBC encoder module 210 operates to
apply symbols S.sub.0, S.sub.0*, S.sub.1, and -S.sub.1* to the
lower-SNR data streams 0 and 1 of far-field STA0 104. As noted
above, STBC encoder module 210 may optionally be applied to the
higher-SNR data streams 0 and 1 of near-field STA1 106 (as
indicated by the dashed arrows in FIG. 2A). Therefore, although the
following disclosures describe the application of STBC symbols to
the lower-SNR data streams of far-field STA0 104, it will be
understood that the STBC symbols may be equally applied to the
higher-SNR data streams of near-field STA1 106 or to both STA0 104
and STA1 106.
[0035] As shown, STBC encoder module 210 encodes 2 symbols in a
pair across the data streams 0 and 1 for STA0 104 along two time
slots t and t+1. The STBC encoded stream 0 of STA0 104 are grouped
and forwarded to the SOMA QAM constellation map processing module
220 of stream 0, as noted above. Similarly, the STBC encoded stream
1 of STA0 104 are grouped and forwarded to the SOMA QAM
constellation map processing module 230 of stream 1.
[0036] For the case in which only the lower-SNR data streams 0 and
1 of far-field STA0 104 are subjected to STBC encoding, the
transmission rate of STA0 104 will be half of the transmission rate
of STA1 106. After the STBC encoding is applied to STA0 104, the
bit level information may be pulled back. The SOMA QAM
constellation processing module 230 then operates to apply SOMA QAM
mapping to each stream and to each sub-carrier for the
corresponding symbols.
[0037] FIG. 2B depicts the STBC decoding process 250 of modulated
data streams 200, in accordance with various embodiments of the
present disclosure. As shown for the single receiver case, the
received signal at receiver RX at t.sub.0 is y.sub.0 and at t.sub.1
is y.sub.1, which may be expressed as:
y.sub.0=s.sub.0.times.h.sub.t.times.0-s.sub.1*.times.h.sub.t.times.1
y.sub.1=s.sub.1.times.h.sub.t.times.0+s.sub.0*.times.h.sub.t.times.1
where h.sub.t.times.0 and h.sub.t.times.1 are the channel gains
between TX0 and RX and between TX1 and RX, respectively and
s.sub.0, s.sub.0*, s.sub.1, and -s.sub.1* are the transmitted
signals. Based on the received signals y.sub.0 and y.sub.1, the
transmitted signals may be decoded by:
=h.sub.t.times.0*.times.y.sub.0+h.sub.t.times.1.times.y.sub.1*
=-h.sub.t.times.1.times.y.sub.0*+h.sub.t.times.0*.times.y.sub.1
[0038] For the two receiver case, the received signal at receiver
RX0 at time t.sub.0 is y.sub.00 and at time t.sub.1 is y.sub.10.
Similarly, the received signal at receiver RX1 at time t.sub.0 is
y.sub.01 and at time t.sub.1 is y.sub.11. The received signals
y.sub.00, y.sub.10, y.sub.01, and y.sub.11 may be expressed as
follows:
y.sub.00=s.sub.0.times.h.sub.00-s.sub.1*.times.h.sub.01
y.sub.10=s.sub.1.times.h.sub.00+s.sub.0*.times.h.sub.01
y.sub.01=s.sub.0.times.h.sub.10-s.sub.1*.times.h.sub.11
y.sub.11=s.sub.1.times.h.sub.10+s.sub.0*.times.h.sub.11
where h.sub.00 and h.sub.01 are the channel gains between TX0-RX0
and TX1-RX0, and h.sub.10 and h.sub.11 are the channel gains
between TX0-RX1 and TX1-RX1. The transmitted signals are s.sub.0,
s.sub.0*, s.sub.1, and -s.sub.1*. Based on the received signals
y.sub.00, y.sub.10, y.sub.01, and y.sub.11 the transmitted signals
may be decoded by:
=h.sub.00*.times.y.sub.00+h.sub.01.times.y.sub.10*+h.sub.10*.times.y.sub-
.01+h.sub.11.times.y.sub.11*
=h.sub.10*.times.y.sub.11-h.sub.11.times.y.sub.01*+h.sub.00*.times.y.sub-
.10-h.sub.01.times.y.sub.00*
STBC-Based Pre-SOMA Transmitting Architecture
[0039] FIG. 3A illustrates a high-level functional block diagram of
a representative STBC-based pre-SOMA scheme transmitting
architecture 300, in accordance with various embodiments of the
present disclosure. As shown, the STBC encoding operations 210 are
performed prior to the SOMA QAM constellation map processing 220,
230.
[0040] Moreover, in the depicted embodiment, the higher-SNR data of
near-field STA1 106 are not STBC-encoded for purposes of
simplicity. However, it will be appreciated that the STBC encoding
may also be applied to the STA1 106 data, consistent with the
concepts and principles presented by the instant disclosure.
Therefore, it will be understood that STBC encoding operations may
be applied to the data of either of the near-field or far-field
STAs or to both.
[0041] As shown, transmitting architecture 300 digitally processes
and formats the data bits of lower-SNR data streams 0 and 1 of
far-field STA0 104 and higher-SNR data streams 0 and 1 of
near-field STA1 106 for subsequent processing. In particular, the
data bits corresponding to streams 0 and 1 of both STAs are
scrambled, binary convolutionally encoded, and are correspondingly
interleaved according to bit reliability (e.g., least reliable bits
(LRBs) and most reliable bits (MRBs) respectively allocated for
STA0 104, STA1 106).
[0042] The interleaved bits of STA0 104 are subsequently converted
to symbols to facilitate STBC encoding. However, because in the
illustrated embodiment the STA1 106 data is not subjected to STBC
encoding, the interleaved bits of STA1 106 are not converted to
symbols.
[0043] Transmitting architecture 300 subsequently supplies the
processed lower-SNR data symbols of far-field STA0 104 to STBC
encoder module 210. As noted above, STBC encoder module 210
operates to block encode the STA0 104 data with symbols S.sub.0,
S.sub.0*, S.sub.1, and -S.sub.1* to provide space and time
diversity gains.
[0044] Returning to FIG. 3A, the STBC-encoded STA0 104 stream 0
data bits are grouped with the STA1 106 stream 0 data bits and the
STBC-encoded STA0 104 stream 1 data bits are grouped with the STA1
106 stream 1 data bits. The grouped stream 0 and stream 1 data bits
are the forwarded to the respective stream 0 and stream 1 SOMA QAM
constellation map processing modules 220, 230 which, as noted
above, serves to provide a higher throughput by assigning and
mapping MRBs and LRBs to the various streams. That is, SOMA QAM
constellation map processing modules 220, 230 employ bit combining
and symbol mapping elements that operate to assign the MRBs to the
lower SNR data and to assign LRBs to the higher SNR data. The
STBC-based SOMA modulated symbols of data streams 0, 1 are
subsequently forwarded to respective transmission antenna units for
wireless transmission.
[0045] As noted above, an indication of the application of STBC
operations to the SOMA modulated data is to be included in the
communicated data packet frame structure, preferably in a signal
(SIG) field, such as, for example, the Extremely High Throughput
(EHT) SIG field, to enable recognition of STBC encoding and ensure
proper processing.
STBC-Based Post-SOMA Transmitting Architecture
[0046] As an alternative implementation, FIG. 3B depicts a
high-level functional block diagram of a representative post-SOMA
STBC-based transmitting architecture 350, in accordance with
various embodiments of the present disclosure. As shown,
STBC-encoding operations are performed after the SOMA QAM
constellation map processing 220, 230 and are applied to the SOMA
modulated data of both STAs.
[0047] Specifically, the data bits of both, lower-SNR data streams
0 and 1 of far-field STA0 104 and higher-SNR data streams 0 and 1
of near-field STA1 106 are digitally processed and formatted for
subsequent processing. That is, the data bits are scrambled, binary
convolutionally encoded and correspondingly interleaved according
to bit reliability (e.g., LRBs and MRBs respectively allocated to
STA0 104, STA1 106 stream data).
[0048] In turn, the processed interleaved data bits of streams 0
and 1 corresponding to STA0 104 and STA1 106 are forwarded to the
SOMA-QAM constellation map processing modules 220, 230. The
interleaved data bits of both streams for STA0 104 and STA1 106 are
processed by QAM constellation modulation processing modules 220,
230 that serve to modulate, assign, and correspondingly map LRBs
and MRBs to achieve better throughput, as described above. That is,
SOMA QAM constellation map processing modules 220, 230 employ bit
combining and symbol mapping elements to assign the MRBs to the
lower SNR data and to assign the LRBs to the higher SNR data.
[0049] Turning back to FIG. 3B, the SOMA-QAM modulated data of
far-field STA0 104 (and/or near-field STA1 106) may then be
supplied to STBC-encoding module 210 which, as noted above,
operates to block encode the STA0 104 (and/or near-field STA1 106)
data with symbols S.sub.0, S.sub.0*, S.sub.1, and -S.sub.1* to
provide space and time diversity gains. The STBC-based SOMA
modulated symbols of data streams 0, 1 are subsequently forwarded
to respective transmission antenna units for wireless
transmission.
[0050] Moreover, as noted above, an indication of STBC operations
applied to the SOMA modulated data is to be included in the
communicated data packet frame structure, preferably in the
Extremely High Throughput (EHT) signal (SIG) field, to enable
recognition of STBC encoding and ensure proper processing.
STBC-Based SOMA Processes
[0051] FIG. 4A illustrates a high-level flow diagram of a
representative STBC-based pre-SOMA scheme transmitting process 400
that may be executed by transmitting architecture 300, in
accordance with various embodiments of the present disclosure. It
will be appreciated that the processing tasks may be achieved by
constituent structures, components, and modules of transmitting
architecture 300 or combinations thereof and do not limit the scope
of the present disclosure.
[0052] Process 400 commences at task block 402, in which
transmitting architecture 300 digitally processes and formats the
STA0 104 and STA1 106 data bits for subsequent processing. As
described above, the digital processing of task block 402 includes
scrambling, binary convolutionally encoding, and interleaving
LRB/MRB operations.
[0053] At task block 404, transmitting architecture 300 applies
STBC encoding to one or both of the STA0 104 and STA1 106 data. In
particular, STBC encoder 210 operates to block encode the STA0 104
data with symbols S.sub.0, S.sub.0*, S.sub.1, and -S.sub.1* to
provide space and time diversity gains.
[0054] At task block 406, transmitting architecture 300 groups the
STBC-encoded bits of corresponding streams 0, 1 of STA0 104, STA1
106 data. As noted above, the STBC-encoded STA0 104 stream 0 data
bits are grouped with the STA1 106 stream 0 data bits and the
STBC-encoded STA0 104 stream 1 data bits are grouped with the STA1
106 stream 1 data bits.
[0055] At task block 408, transmitting architecture 300 applies
SOMA QAM constellation mapping to the grouped stream 0 and stream 1
data bits. As discussed above, SOMA QAM constellation mapping
incorporates bit combining and symbol mapping elements to assign
and map MRBs to lower-SNR stream data, and assign and map LRBs to
the higher-SNR stream data during QAM modulation processing. At
task block 410, the STBC-based SOMA data symbols of streams 0, 1
are subsequently forwarded to respective transmission antenna units
for wireless transmission.
[0056] In an alternative implementation, FIG. 4B illustrates a
high-level flow diagram of a representative STBC-based post-SOMA
scheme transmitting process 450 that may be executed by
transmitting architecture 350, in accordance with various
embodiments of the present disclosure.
[0057] Process 450 commences at task block 452, in which in which
transmitting architecture 350 digitally processes and formats the
STA0 104, STA1 106 data bits for subsequent processing. As
described above, the digital processing includes scrambling, binary
convolutionally encoding, and interleaving LRB/MRB operations.
[0058] At task block 454, transmitting architecture 350 applies
SOMA QAM constellation mapping to the digitally processed bits of
STA0 104 and STA1 106, which operates to modulate and assign/map
MRBs, LRBs to the stream data, in the manner described above.
[0059] At task block 456, transmitting architecture 350 applies
STBC encoding to the SOMA symbols. The STBC encoding operates to
block encode the SOMA symbols for space and time diversity gains,
in the manner described above. At task block 458, the STBC-based
SOMA data symbols of streams 0, 1 are subsequently forwarded to
respective transmission antenna units for wireless
transmission.
Representative Simulation Results of STBC-Based SOMA Scheme
[0060] FIG. 5A illustrates the simulation trial packet error rate
(PER) results for various STBC-based and non STBC-based SOMA
scenarios, in accordance with various embodiments of the present
disclosure. In particular, FIG. 5A indicates the simulation PER
results for the following trial scenarios: (a) non STBC-based SOMA
far-field STA QPSK modulated signal; (b) non STBC-based SOMA near
field STA QPSK modulated signal; (c) STBC-based SOMA far-field STA
QPSK modulated signal; (d) STBC-based SOMA near-field STA QPSK
modulated signal; (e) STBC-based SOMA far-field STA 16 QAM
modulated signal; and (f) STBC-based SOMA near-field STA QPSK
modulated signal.
[0061] In view of the simulation trial PER results indicated by
FIG. 5A, it will be appreciated that, at low SNR levels, the
STBC-based SOMA far-field STA QPSK modulated signal (indicated by
curve (c)) and the STBC-based SOMA far-field STA 16 QAM modulated
signal (indicated by curve (e)) exhibit better PER performance than
the other trial scenarios.
[0062] FIG. 5B illustrates the simulation trial throughput results
for various STBC-based and non STBC-based SOMA scenarios, in
accordance with various embodiments of the present disclosure. In
particular, FIG. 5B indicates the simulation throughput results for
the following trial scenarios: (a) non STBC-based SOMA; (b)
STBC-based SOMA with QPSK modulated at a near-field STA and 16 QAM
modulation at a far field STA; and (c) STBC-based SOMA with 16 QAM
modulation at a near-field STA and QPSK modulation at a far-field
STA for different SNR gaps.
[0063] The simulation trial throughput results, as evidenced by
FIG. 5B, indicate that the throughput of STBC-based SOMA with 16
QAM modulation at a near-field STA and QPSK modulation at a
far-field STA (indicated by curve (c)) consistently outperforms the
throughput of non STBC-based SOMA (indicated by curve (a)) at lower
SNR levels. Therefore, although the throughput performance of non
STBC-based SOMA is better at higher SNR levels, the STBC-based SOMA
scheme provides better throughput performance at lower SNR levels
due to diversity gain effects.
[0064] The disclosed embodiments therefore provide for a WLAN
transmitting architecture and transmission process that combines
STBC encoding techniques with SOMA modulation schemes that are
configured to improve the throughput of WLAN signals at lower SNR
levels. As detailed above, the STBC encoding techniques may be
applied to SOMA-modulated data of a single STA or a combination of
STAs, in accordance with the disclosed embodiments.
[0065] It will be understood that the operations and functionality
of the described WLAN transmitting architecture, processes, and/or
constituent structures and elements may be achieved by
hardware-based, software-based, firmware-based elements and/or
combinations thereof. Such operational alternatives do not, in any
way, limit the scope of the present disclosure.
[0066] It will also be understood that, although the inventive
concepts and principles presented herein have been described with
reference to specific features, structures, and embodiments, it is
clear that various modifications and combinations may be made
without departing from the disclosures. The specification and
drawings are, accordingly, to be regarded simply as an illustration
of the inventive concepts and principles as defined by the appended
claims, and are contemplated to cover any and all modifications,
variations, combinations or equivalents that fall within the scope
of the present disclosure.
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