U.S. patent application number 14/661650 was filed with the patent office on 2015-08-13 for method and system for content-aware mapping/error protection using different spatial streams.
This patent application is currently assigned to BROADCOM CORPORATION. The applicant listed for this patent is BROADCOM CORPORATION. Invention is credited to Hooman Honary, Jeyhan Karaoguz, Nambirajan Seshadri, Jason Trachewsky.
Application Number | 20150229369 14/661650 |
Document ID | / |
Family ID | 38986186 |
Filed Date | 2015-08-13 |
United States Patent
Application |
20150229369 |
Kind Code |
A1 |
Honary; Hooman ; et
al. |
August 13, 2015 |
Method and system for content-aware mapping/error protection using
different spatial streams
Abstract
Aspects of a method and system for content-aware mapping/error
protection using different spatial streams are presented. Aspects
of a system for handling multimedia information in a communication
system may include a transmitter that enables control of a MAC
layer and/or a PHY layer, in a wireless communication device to
wirelessly communicate different portions of multimedia information
via different spatial streams based on content of the multimedia
information. The system may also comprise a processor that enables
definition of a plurality of priority classes based on the content
associated with at least a portion of the multimedia
information.
Inventors: |
Honary; Hooman; (Newport
Coast, CA) ; Karaoguz; Jeyhan; (Irvine, CA) ;
Seshadri; Nambirajan; (Irvine, CA) ; Trachewsky;
Jason; (Menlo Park, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BROADCOM CORPORATION |
Irvine |
CA |
US |
|
|
Assignee: |
BROADCOM CORPORATION
Irvine
CA
|
Family ID: |
38986186 |
Appl. No.: |
14/661650 |
Filed: |
March 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11492721 |
Jul 25, 2006 |
8995411 |
|
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14661650 |
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Current U.S.
Class: |
375/267 |
Current CPC
Class: |
H04B 7/028 20130101;
H04B 7/0413 20130101; H04B 7/0482 20130101; H04W 72/10 20130101;
H04L 65/4076 20130101; H04L 47/10 20130101; H04B 7/0417
20130101 |
International
Class: |
H04B 7/04 20060101
H04B007/04; H04L 29/06 20060101 H04L029/06; H04B 7/02 20060101
H04B007/02 |
Claims
1. A communication device that wirelessly communicates a multimedia
element using a plurality of antennas to a single recipient device,
the communication device comprising: a processor configured to
generate first data and second data from the multimedia element
based on an importance level characteristics relating to differing
portions of the multimedia element; and a transmitter block
configured to simultaneously communicate both the first data and
the second data via the plurality of antennas to the single
recipient device, the first data being communicated via a first
transmission output and the second data being communicated via a
second transmission output, at least one of the first transmission
output and the second transmission output comprising a beam formed
output.
2. The communication device of claim 1, wherein the multimedia
element comprises streamed multimedia content.
3. The communication device of claim 1, wherein the importance
level characteristics comprise a plurality of priority classes.
4. The communication device of claim 1, wherein the first
transmission output and the second transmission output comprise
differing Multiple Input Multiple Output (MIMO) spatial
streams.
5. The communication device of claim 1, wherein the first
transmission output comprises I-frames and the second transmission
output comprises P-frames.
6. The communication device of claim 1, wherein the first
transmission output is transmitted from at least one first antenna
and the second transmission output is transmitted from at least one
differing second antenna.
7. The communication device of claim 1, wherein the first
transmission output comprises first coding parameters and the
second transmission output comprises second coding parameters that
differ from the first coding parameters.
8. A communication device that wirelessly communicates a single
data element to a single recipient device, the communication device
comprising: a processor configured to analyze at least one
characteristic associated with the single data element to generate
from the single data element a plurality of independent bit
streams, each of the plurality of independent bit streams having an
assigned one of at least two priority levels; and a transmitter
block configured to simultaneously and independently communicate
the plurality of bit streams using at least a first RF output and a
second RF output, at least one of the first RF output and the
second RF output comprises a beamformed output, the first RF output
and the second RF output differ in at least one communication
pathway characteristic, and the first RF output and the second RF
output being communicated for receipt by the single recipient
device for reconstruction into the single data element.
9. The communication device of claim 8, wherein the single data
element comprises multimedia content.
10. The communication device of claim 9, wherein the single data
element comprises streamed multimedia content.
11. The communication device of claim 10, wherein the first RF
output comprises I-frames and the second RF output comprises
P-frames.
12. The communication device of claim 8, wherein the first RF
output and the second RF output comprise differing Multiple Input
Multiple Output (MIMO) spatial streams.
13. The communication device of claim 8, wherein the first RF
output is transmitted from at least one first antenna and the
second RF output is transmitted from at least one differing second
antenna.
14. The communication device of claim 8, wherein the first RF
output comprises first coding parameters and the second RF output
comprises second coding parameters that differ from the first
coding parameters.
15. A communication device that wirelessly communicates a single
data element to a single recipient device, the single data element
having higher priority portions and lower priority portions, the
communication device comprising: a processor configured to generate
from the single data element a first bit stream and a second bit
stream, the first bit stream being based on the higher priority
portions and the second bit stream being based on the lower
priority portions; and a transmitter block configured to
simultaneously communicate both the first bit stream via a first RF
output and the second bit stream via a second RF output, at least
one of the first RF output and second RF output comprising a
beamformed output, and the first RF output and the second RF output
differing in at least one communication pathway characteristic, and
wherein the first RF output and the second RF output being
communicated for receipt by the single recipient device for
reconstruction of the single data element.
16. The communication device of claim 15, wherein the single data
element comprises multimedia content.
17. The communication device of claim 16, wherein the single data
element comprises streamed multimedia content.
18. The communication device of claim 17, wherein the first RF
output comprises I-frames and the second RF output comprises
P-frames.
19. The communication device of claim 15, wherein the first RF
output and the second RF output comprise differing Multiple Input
Multiple Output (MIMO) spatial streams.
20. The communication device of claim 15, wherein the first RF
output is transmitted from at least one first antenna and the
second RF output is transmitted from at least one differing second
antenna.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY
REFERENCE
[0001] The present U.S. Utility patent application claims priority
pursuant to 35 U.S.C. .sctn.120 as a continuation of U.S. Utility
application Ser. No. 11/492,721 entitled "Method and System for
Content-Aware Mapping/Error Protection Using Different Spatial
Streams," filed Jul. 25, 2006, which is hereby incorporated herein
by reference in its entirety and made part of the present U.S.
Utility patent application for all purposes.
[0002] This application makes reference to:
U.S. application Ser. No. 11/492,667 filed on Jul. 25, 2006, now
issued as U.S. Pat. No. 8,917,674; U.S. application Ser. No.
11/492,391 filed on Jul. 25, 2006, now abandoned; U.S. application
Ser. No. 11/492,381 filed on Jul. 25, 2006, now issued as U.S. Pat.
No. 8,411,581; and U.S. application Ser. No. 11/492,390 filed on
Jul. 25, 2006, now issued as U.S. Pat. No. 7,877,674.
[0003] Each of the above stated applications is hereby incorporated
herein by reference in its entirety.
FIELD OF THE INVENTION
[0004] Certain embodiments of the invention relate to data
communications. More specifically, certain embodiments of the
invention relate to a method and system for content-aware
mapping/error protection using different spatial streams.
BACKGROUND OF THE INVENTION
[0005] Multiple input multiple output (MIMO) systems are wireless
communications systems that are specified in, for example,
resolution 802.11n from the Institute of Electrical and Electronics
Engineers (IEEE). A MIMO system that receives a signal Y may
compute a channel estimate matrix, H, based on the received signal.
The signal may comprise information generated from a plurality of
information sources. A transmitting MIMO system may utilize a
plurality of transmitting antennas when transmitting the signal Y.
A receiving MIMO system may utilize a plurality of receiving
antennas when receiving the signal Y. The channel estimate matrix
for a downlink RF channel, H.sub.down, may describe a
characteristic of the wireless transmission medium in the
transmission path from a transmitter, to a receiver. The channel
estimate for an uplink RF channel, H.sub.up, may describe a
characteristic of the wireless transmission medium in the
transmission path from the receiver to the transmitter. According
to the principle of reciprocity, a characteristic of the wireless
transmission medium in the transmission path from the transmitter
to the receiver may be assumed to be identical to a corresponding
characteristic of the wireless transmission medium in the
transmission path from the receiver to the transmitter.
[0006] When the transmitter and receiver are MIMO systems,
corresponding beamforming matrices may be configured and utilized
for transmitting and/or receiving signals based on the
characteristic channel estimate matrix H. Beamforming is a method
for signal processing that may allow a transmitting MIMO system to
combine a plurality of signals in a transmitted signal Y.
Beamforming is also a method for signal processing that may allow a
receiving MMO system to separate individual signals in a received
signal Y.
[0007] Further limitations and disadvantages of conventional and
traditional approaches will become apparent to one of skill in the
art, through comparison of such systems with some aspects of the
present invention as set forth in the remainder of the present
application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0008] A system and/or method is provided for content-aware
mapping/error protection using different spatial streams,
substantially as shown in and/or described in connection with at
least one of the figures, as set forth more completely in the
claims.
[0009] These and other advantages, aspects and novel features of
the present invention, as well as details of an illustrated
embodiment thereof, will be more fully understood from the
following description and drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0010] FIG. 1A is a block diagram of exemplary communications
circuitry that may be utilized in connection with an embodiment of
the invention.
[0011] FIG. 1B illustrates an exemplary architecture for source
layer optimization for transmitting data, in accordance with an
embodiment of the invention.
[0012] FIG. 2 is an exemplary diagram illustrating beamforming that
may be utilized in connection with an embodiment of the
invention.
[0013] FIG. 3 is a block diagram of an exemplary MIMO transmitter
system for content aware mapping and error protection using
different spatial streams, in accordance with an embodiment of the
invention.
[0014] FIG. 4 is a flowchart illustrating exemplary steps for
content aware mapping and error protection using different spatial
streams, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Certain embodiments of the invention may be found in a
method and system for content-aware mapping/error protection using
different spatial streams. Aspects of a system for handling
multimedia information in a communication system may comprise a
transmitter that enables control of a MAC layer and/or a PHY layer,
in a wireless communication device to wirelessly communicate
different portions of multimedia information via different spatial
streams based on content of the multimedia information. The system
may also comprise a processor that enables definition of a
plurality of priority classes based on the content associated with
at least a portion of the multimedia information.
[0016] FIG. 1A is a block diagram of exemplary communications
circuitry that may be utilized in connection with an embodiment of
the invention. With reference to FIG. 1A, there is shown a memory
processor 172, a transceiver 174, an RF front end 180, a plurality
of receive antennas 176a, . . . , 176n, and a plurality of
transmitting antennas 178a, . . . , 178n. The transceiver 174 may
comprise a processor 182, a receiver 184, and a transmitter
186.
[0017] The memory 172 may enable storage and/or retrieval of
information that may be transmitted via one or more transmitting
antennas 178a, . . . , 178n, received via one or more receive
antennas 176a, . . . , 176n, and/or storage of code that may enable
control of the operation of the transceiver 174.
[0018] The processor 182 may enable digital receiver and/or
transmitter functions in accordance with applicable communications
standards. These functions may comprise, but are not limited to,
tasks performed at lower layers in a relevant protocol reference
model. These tasks may further comprise the physical layer
convergence procedure (PLCP), physical medium dependent (PMD)
functions, and associated layer management functions.
[0019] The receiver 184 may be enable digital receiver functions
that may comprise, but are not limited to, fast Fourier transform
processing, beamforming processing, equalization, demapping,
demodulation control, deinterleaving, depuncture, and decoding. The
transmitter 186 may enable digital transmitter functions that
comprise, but are not limited to, coding, puncture, interleaving,
mapping, modulation control, inverse fast Fourier transform
processing, beamforming processing. The RF front end 180 may enable
reception of analog RF signals via antennas 176a, . . . , 176n,
converting the RF signal to baseband, and generating digital
representations of the received analog baseband signals. The
digital representation may be a complex quantity comprising I and Q
components. The RF front end 180 may also transmit analog RF
signals via an antenna 178a, . . . , 178n, converting a digital
baseband signal to an analog RF signal.
[0020] In operation, the processor 182 may receive data from the
receiver 184. The processor 182 may store received data to the
memory 172 for subsequent analysis and/or processing. The processor
182 may retrieve information from the memory 172. The retrieved
information may be transmitted via an RF channel by the transmitter
186. The processor 182 may associate one or more priority classes
to the retrieved information. The transmitter 186 may process and
transmit the information via the RF channel based on the
corresponding priority classes.
[0021] FIG. 1B illustrates an exemplary architecture for source
layer optimization for transmitting data, in accordance with an
embodiment of the invention. Referring to FIG. 1B, there is shown a
processor 110 and a transmit block 115. The transmit block 115 may
comprise a source encoder block 120, a memory block 122, a source
layer multiplexer block 124, a PHY/MAC block 126, a cross-layer
partitioner block 128, a parameter control block 130, and transmit
antennas 132a, . . . , 132b.
[0022] The source encoder block 120 may comprise suitable logic,
circuitry, and/or code that may be utilized to enable compression
of data prior to transmission. For example, the compressed data may
be video data in MPEG-4 format. The source encoder block 120 may
also communicate information about the compressed data to the
cross-layer partitioner block 128. The information communicated may
relate to the type of compression. For example, if the compressed
data comprises video data, the source encoder block 120 may
communicate the specific type of compression, such as MPEG-1,
MPEG-2, MPEG-4, H.261, H.263, or H.264. The source encoder block
120 may also communicate the type of chroma subsampling used, such
as, for example, 4-4-4, 4-2-2, or 4-2-0 chroma subsampling.
[0023] The source layer multiplexer block 124 may comprise suitable
logic, circuitry, and/or code that may be utilized to enable
reading data from, for example, the memory block 122 and
communicating various portions of the data to the PHY/MAC 126. The
data may be split into the various portions according to
information from the cross-layer partitioner block 128. The
information from the cross-layer partitioner block 128 may
comprise, for example, priority for the various portions of the
data. The cross-layer partitioner block 128 may also indicate that
portions of data with certain priority may be communicated via
certain outputs of the source layer multiplexer block 124.
[0024] The PHY/MAC block 126 may comprise suitable logic,
circuitry, and/or code that may be utilized to enable conversion of
input data in a digital format to output suitably modulated analog
data ready for transmission. For example, the PHY/MAC block 126 may
apply a forward error correction (FEC) code to the digital data.
The PHY/MAC block 126 may also apply a specific RF modulation to
the analog signal, which may have been converted from the digital
data. The PHY/MAC block 126 may additionally communicate analog
signals to different transmit antennas 132a, . . . , 132b, in a
part of a multiple-input multiple-output (MIMO) architecture.
[0025] In an embodiment of the invention, the PHY/MAC block 126 may
receive one or more streams of digital data. The PHY/MAC block 126
may then operate on the multiple streams as indicated by, for
example, the parameter control block 130. Accordingly, the PHY/MAC
block 126 may, for example, apply a specific FEC code to each
digital stream. Each digital stream may then be converted to analog
RF signal, which may be modulated by a specific RF modulation
scheme. Each modulated RF signal may then be communicated to one or
more antennas to be transmitted.
[0026] The cross-layer partitioner block 128 may comprise suitable
logic, circuitry, and/or code that may be utilized to enable
assigning a priority to portions of data in the memory block 122.
The priority may be based on, for example, perceived importance of
the information in the memory block 122. For example, if the data
in the memory block 122 comprises video data relating to video
frames, a portion of the data that comprises information about an
entire frame, such as, example, an I-frame, may have a high
priority. Other frames, such as, for example, P-frames may have a
lower priority than I-frames since P-frames may depend on the
I-frames for additional information. P-frames that depend on other
primary P-frames may be, for example, assigned a lower priority
than the P-frames that may only depend on I-frames. A B-frame that
depends on a prior and a subsequent frame may be assigned, for
example, a lowest priority. The number of priorities may be design
and/or implementation dependent.
[0027] The cross-layer partitioner block 128 may also indicate to
the source layer multiplexer block 124 that data with certain
priorities may be communicated to the PHY/MAC block 126 via
specific outputs of the source layer multiplexer block 124. The
cross-layer partitioner block 128 may then communicate to the
parameter control block 130 those operations that may be performed
on the various streams of data communicated by the source layer
multiplexer 124.
[0028] Specific streams of data may be communicated to specific
transmit antennas. The cross-layer partitioner block 128 may have
information regarding the propagation path from each transmit
antenna 132a, . . . , 132b to a receive antenna, where data
transmitted via one transmit antenna may be received with fewer bit
errors, for example, than data transmitted by another transmit
antenna. Accordingly, this information may be used to determine
which data may be transmitted via which transmit antenna. The
information regarding the propagation path for each transmit
antenna may be generated, for example, from feedback information
from the receiving devices. Alternatively, the information may be
generated from feedback information from a receiver co-located with
the transmit block 115.
[0029] The parameter control block 130 may comprise suitable logic,
circuitry, and/or code that may be utilized to enable controlling
of various operations to the digital data in the PHY/MAC block 126.
For example, the parameter control block 130 may determine the FEC
code and/or the RF modulation that may be used by the PHY/MAC block
126 for specific portions of data. The parameter control block 130
may also determine which antennas may be used to transmit which
portions of data by controlling routing of the data within the
PHY/MAC block 126 to the specific antennas.
[0030] However, there may be other embodiments of the invention
that route signals to specific antennas using other methods. For
example, some embodiments of the invention may select the antenna
used to transmit data by selecting the source layer multiplexer 124
output used to communicate data from the source layer multiplexer
124 to the PHY/MAC 126. Data communicated to the PHY/MAC 126 via
specific outputs to the PHY/MAC 126 may be transmitted via specific
transmit antennas. For example, the data, Output1, may be
transmitted by the transmit antenna 132a, and the data, Output2,
may be transmitted by the transmit antenna 132b.
[0031] In operation, the source encoder block 120 may compress data
and store the compressed data in the memory block 122. For
simplicity, the data may be assumed to be video data compressed
using the MPEG-4 format, two priority classes may be used--a high
priority class and a low priority class, and Output1 data and
Output2 data may be transmitted by the transmit antennas 132a and
132b, respectively. The source encoder block 120 may communicate to
the cross layer partitioner block 128 that the compressed data is
video data using the MPEG-4 format. The source encoder block 120
may also communicate, for example, start and end memory addresses
for the stored video data corresponding to a frame, the frame
number, and the type of frame that may be stored. The type of frame
may be, for example, I-frame, P-frame, and B-frame. Other
information may also be communicated, such as, for example, the
chroma subsampling format.
[0032] The cross layer partitioner block 128 may then determine a
priority to assign to each frame. An exemplary priority class
algorithm may assign a high priority for all I-frames and a low
priority for all other frames. The priority for the video data in
the memory block 122 may be communicated to the source layer
multiplexer block 124. The source layer multiplexer 124 may read
data from the memory block 122, and may output, for example, high
priority data as Output1 and the low priority data as Output2.
[0033] The cross layer partitioner block 128 may also communicate
to the parameter control block 130 the operations to be applied to
each stream of data, namely, Output1 and Output2. For example, the
parameter control block 130 may indicate that the high priority
data, Output1, may have applied to it a forward error correction
(FEC) code A that may have a greater overhead in the number of bits
used than a FEC code B. However, using the FEC code A may allow a
receiving unit to correct a larger number of faulty bits than when
using the FEC code B.
[0034] The cross layer partitioner block 128 may also communicate
to the parameter control block 130 to use, for example, quadrature
phase shift keying (QPSK) RF modulation rather than 16 quadrature
amplitude modulation (16 QAM) RF modulation for the high priority
data Output1. The QPSK RF modulation may have a smaller data
throughput than the 16 QAM RF modulation, however, the QPSK RF
modulation may be more reliable for a given transmission
environment. Additionally, the transmit antenna 132a may exhibit
more reliable transmission characteristics than the transit antenna
132b. If the transmission environment changes such that the
transmit antenna 132b exhibits a more reliable transmission
characteristics than the transmit antenna 132a, then the cross
layer partitioner block 128 may indicate that the higher priority
data be output as Output2.
[0035] The cross layer partitioner block 128 may also take into
account feedback information from the receiving device to maximize
throughput for transmission of the high priority and low priority
data. This may allow, for example, the cross layer partitioner
block 128 to select from a plurality of FEC codes and from a
plurality of RF modulation schemes for a plurality of priority
classes. Similarly, MIMO transmission may utilize beamforming, in
which one antenna may be selected for transmission of particular
stream of data, or a plurality of antennas may be selected for
transmission of a particular stream of data.
[0036] Although feedback information from a receiving device may be
used for transmission, the invention need not be so limited. For
example, feedback data from a receiver that is co-located with the
transmitting device may also be used. Accordingly, for example, the
processor 110 may communicate the feedback data and/or instructions
to the transmit block 115. For example, the processor 110 may
process the feedback data from a co-located receiving device, and
communicate information to the transmit block 115. The information
may be used, for example, to control the operations on the data
streams by the PHY/MAC block 126.
[0037] U.S. application Ser. No. 11/327,690 filed Jan. 6, 2006,
provides a detailed description of feedback in a MIMO system, which
is hereby incorporated herein by reference in its entirety.
[0038] Although an embodiment of the invention may have been
described using a plurality of blocks, the invention need not be so
limited. Accordingly, other embodiments of the invention may use
different blocks that may encompass various functionalities.
[0039] FIG. 2 is an exemplary diagram illustrating beamforming that
may be utilized in connection with an embodiment of the invention.
Referring to FIG. 2 there is shown a transmitting mobile terminal
202, a receiving mobile terminal 222, and a plurality of RF
channels 242. The transmitting mobile terminal 202 comprises a
beamforming V matrix block 204, a first source signal s.sub.1 206,
a second source signal s.sub.2 208, a third source signal s.sub.3
210, and a plurality of transmitting antenna 212, 214, and 216. The
receiving mobile terminal 222 comprises a beamforming U* matrix
block 224, a first destination signal s.sub.1 226, a second
destination signal s.sub.2 228, a third destination signal s.sub.3
230, and a plurality of receiving antenna 232, 234, and 236.
[0040] In operation, the transmitting antenna 212 may enable
transmission of a signal x.sub.1, the transmitting antenna 214 may
enable transmission of a signal x.sub.2, and the transmitting
antenna 216 may enable transmission of a signal x.sub.3. In a
beamforming operation, each of the transmitted signals x.sub.1,
x.sub.2, and x.sub.3 may be a function of a weighted summation of
at least one of the plurality of the source signals s.sub.1,
s.sub.2, and s.sub.3. The weights may be determined by the
beamforming V matrix such that:
X=VS equation[1a]
where X may be a 3.times.1 vector representation of the transmitted
signals x.sub.1, x.sub.2, and x.sub.3, for example:
X = [ x 1 x 2 x 3 ] equation [ 1 b ] ##EQU00001##
S may be a 3.times.1 vector representation of the source signals
s.sub.1, s.sub.2, and s.sub.3, for example:
S = [ s 1 s 2 s 3 ] equation [ 1 c ] ##EQU00002##
and V may be a 3.times.3 matrix representation of the beamforming V
matrix, for example:
V = [ v 11 v 12 v 13 v 21 v 22 v 23 v 31 v 32 v 33 ] equation [ 1 d
] ##EQU00003##
[0041] The receiving antenna 232 may receive a signal y.sub.1, the
receiving antenna 234 may receive a signal y.sub.2, and the
receiving antenna 236 may receive a signal y.sub.3. The plurality
of RF channels 242 may be characterized mathematically by a
transfer coefficient matrix H. The transfer coefficient matrix H
may also be referred to as a channel estimate matrix.
[0042] The plurality of received signals y.sub.1, y.sub.2, y.sub.3,
may be expressed as a function of the plurality of transmitted
signals x.sub.1, x.sub.2, x.sub.3, and the transfer coefficient
matrix H in the following equation, for example:
Y=HX equation[2a]
where Y may be a 3.times.1 vector representation of the received
signals y.sub.1, y.sub.2, and y.sub.3, for example:
Y = [ y 1 y 2 y 3 ] equation [ 2 b ] ##EQU00004##
and H may be a 3.times.3 matrix representation of the transfer
coefficient matrix, for example:
H = [ h 11 h 12 h 13 h 21 h 22 h 23 h 31 h 32 h 33 ] equation [ 2 c
] ##EQU00005##
[0043] A representation for the transfer coefficient matrix H may
be computed passed on the beamforming V matrix utilized in the
transmitter 202, and the beamforming U* matrix utilized in the
receiver 222 by applying a singular value decomposition (SVD)
method. When utilizing SVD, the matrix H from may be represented as
in the following equation:
H = UDV * where equation [ 3 a ] V * = 1 V and equation [ 3 b ] U =
1 U * equation [ 3 b ] ##EQU00006##
based on the unitary matrix properties of the beamforming matrices
V and U*. For a given matrix M, the matrix M* may represent a
Hermitian transform for the matrix M. The matrix D may comprise a
plurality of nonzero matrix diagonal elements, the values of which
may correspond to at least a portion of singular values associated
with the matrix H as shown in the following equation, for
example:
D = [ .lamda. 1 , 1 0 0 0 .lamda. 1 , 1 0 0 0 0 0 0 .lamda. 1 , 1 ]
equation [ 4 ] ##EQU00007##
where .lamda..sub.i,i may represent singular values associated with
the matrix H, and the index A may represent a value equal to the
lesser value between a number of transmitting antennas at the
transmitter 202, and a number of receiving antennas at the receiver
222.
[0044] The beamforming operation at the transmitter 202 may be
represented by equation [1a]. Based on equations[1a] and [2a], the
received signal vector Y may be represented based on the source
signal vector S as follows:
Y=H.times.VS equation[5]
[0045] At the receiver 222, the received destination signals
s.sub.1 226, s.sub.2 228, and s.sub.3 230 may be expressed as a
function of the received signal vector Y, and the beamforming
matrix U* as in the following equation:
S=U*Y equation[6a]
where S may be a 3.times.1 vector representation for the received
destination signals s.sub.1 226, s.sub.2 228, and s.sub.3 230.
Based on equations[3a] and [5], the received destination signals
may be expressed as a function of the source signals as in the
following equation:
S=U*UDV*VS equation[6b]
or
S=D.times.S equation[6c]
[0046] Based on equation[6c], a received destination signal s.sub.i
may be proportional to the corresponding source signal s.sub.i,
where i is an index to one of the plurality of corresponding
signals, as in the following equation:
s.sub.i=.lamda..sub.iis.sub.i equation[7]
where .lamda..sub.i,i may represent a corresponding value from the
diagonal vector D as in equation[4]. The singular value
.lamda..sub.i,i may represent a measure of signal gain between the
transmitter 202 and the receiver 222. Singular values from the
diagonal vector D, in equation[4], may be sorted based on the
following relationship, for example:
.lamda..sub.11.gtoreq..lamda..sub.22.gtoreq. . . .
.gtoreq..lamda..sub.(A-1)(A-1).gtoreq..lamda..sub.AA
equation[8]
where and the index A may represent a value equal to the lesser
value between a number of transmitting antennas at the transmitter
202, and a number of receiving antennas at the receiver 222.
[0047] Correspondingly, based on signal to noise ratio (SNR) and/or
signal strength measurements, for the destination signals may
similarly be sorted based on the following relationship, for
example:
s.sub.1.gtoreq.s.sub.2.gtoreq. . . .
.gtoreq.s.sub.N.sub.SS.sub.-1.gtoreq.s.sub.N.sub.SS equation[9]
where N.sub.SS may represent a number of source signals at the
transmitter 202.
[0048] The equation[9] may present a signal strength relationship
among the destination signals such that destination signal 226 may
represent a stronger signal in comparison to destination signal
228, while destination signal 228 may represent a stronger signal
in comparison to the destination signal 230, for example.
[0049] FIG. 3 is a block diagram of an exemplary MIMO transmitter
system for content aware mapping and error protection using
different spatial streams, in accordance with an embodiment of the
invention. Referring to FIG. 3, there is shown a transmitter 300, a
processor 342, a memory 340, and a plurality of transmitting
antennas 315a, . . . , 315n. The transmitter 300 may comprise a
channel encoder block 302, a puncture block 304, spatial parser
block 305, a plurality of frequency interleaver blocks 306a, . . .
, 306n, a plurality of constellation mapper blocks 308a, . . . ,
308n, a plurality of serial to parallel converter blocks 309a, . .
. , 309n, a beamforming V matrix block 312, a plurality of inverse
fast Fourier transform (IFFT) blocks 310a, . . . , 310n, a
plurality of insert guard interval (GI) window blocks 311a, . . . ,
311n, and a plurality of radio front end (RFE) blocks 314a, . . . ,
314n.
[0050] The channel encoder block 302 may comprise suitable logic,
circuitry, and/or code that may enable transformation of received
binary input data blocks by applying a forward error correction
(FEC) technique, for example, binary convolutional coding (BCC).
The application of FEC techniques, also known as "channel coding",
may improve the ability to successfully recover transmitted data at
a receiver by appending redundant information to the input data
prior to transmission via an RF channel. The ratio of the number of
bits in the binary input data block to the number of bits in the
transformed data block may be known as the "coding rate". The
coding rate, R, may be specified using the notation
i.sub.b/t.sub.b, where t.sub.b represents the total number of bits
that comprise a coding group of bits, while i.sub.b represents the
number of information bits that are contained in the group of bits
t.sub.b. Any number of bits t.sub.b-i.sub.b may represent redundant
bits that may enable the receiver 184 to detect and correct errors
introduced during transmission of information from the transmitter
202 to the receiver 222 via a wireless communication medium 242,
for example. Increasing the number of redundant bits may enable
greater capabilities at the receiver to detect and correct errors
in received information bits. Increasing the number of redundant
bits may increase the value of t.sub.b without increasing the
number of information bits i.sub.b, and correspondingly reduce the
coding rate, R. The resulting lower coding rate, R, may be referred
to as a "stronger" coding rate in comparison to a higher coding
rate, R. The stronger coding rate may also correspond to a stronger
error protection scheme. The stronger error protection scheme may
correspondingly enable greater capabilities at the receiver to
detect and correct errors in received information bits. Decreasing
the number of redundant bits may decrease the value of t.sub.b
without decreasing the number of information bits i.sub.b, and
correspondingly increase the coding rate, R. The resulting higher
coding rate, R, may be referred to as a "weaker" coding rate in
comparison to a lower coding rate, R.
[0051] The invention is not limited to BCC, and any one of a
plurality of coding techniques, for example, Turbo coding, low
density parity check (LDPC) coding, or various block coding
techniques such as Reed-Solomon FEC may also be utilized.
[0052] The puncture block 304 may comprise suitable logic,
circuitry, and/or code that may enable alteration of a coding rate
for received encoded data by removing redundant bits from the
received transformed binary input data blocks. For example, for
each contiguous block of 4 bits of received data that is encoded
based on an R=1/2 coding rate BCC, the received data may comprise 2
information bits, and 2 redundant bits. By removing 1 of the
redundant bits in the group of 4 received bits, the puncture block
304 may alter the coding rate from R=1/2 to R=2/3, for example.
[0053] The spatial parser block 305 may comprise suitable logic,
circuitry, and/or code that may enable a block of data bits
associated with a single bit stream to be divided into a plurality
of parsed blocks of data bits, each of which may be associated with
a corresponding plurality of parsed bit streams. Each of the parsed
bit streams may be referred to as a spatial stream. A spatial
stream may comprise an identifiable block of bits that may be
processed within a MIMO system.
[0054] The spatial parser block 305 may receive the block of data
bits associated with the single bit stream, b.sub.db, and generate
a plurality of parsed bit streams, b.sub.st[i], where i may be an
index identifying a specific parsed bit stream among the plurality
of parsed bit streams. The range of values for the index i may be
represented as follows:
0.ltoreq.i.ltoreq.N.sub.SS-1 equation[10]
where N.sub.SS may represent a number of spatial streams, for
example N.sub.SS=2 may indicate a MIMO system that comprises 2
spatial streams.
[0055] Each of the parsed bit streams, b.sub.st[i], may comprise a
portion of the bits contained in the single bit stream b.sub.db.
The single bit stream b.sub.db may comprise the plurality of bits
collectively contained in the corresponding plurality of parsed bit
streams b.sub.st[i].
[0056] Various embodiments of the invention may not be limited to a
specific method for allocating bits from a single bit stream to a
plurality of spatial streams. For example, given a block of
N.sub.TOT bits received in a from a single bit stream, the spatial
parser block 305 may assign about N.sub.TOT/N.sub.SS bits to each
of the plurality of N.sub.SS spatial streams. A first block of
N.sub.TOT/N.sub.SS bits from the bit stream b.sub.db may be
assigned to spatial stream 1, a second block of N.sub.TOT/N.sub.SS
bits may be assigned to spatial stream 2, and an N.sub.SS.sup.th
block of N.sub.TOT/N.sub.SS bits may be assigned to spatial stream
N.sub.SS, for example. Alternatively, a k.sup.th bit from the bit
stream b.sub.db, where k may represent an index for a bit in the
block of data bits associated with the bit stream b.sub.db, may be
assigned to spatial stream i as indicated in the following
equation, for example:
k.sub.i=floor(k/N.sub.SS)+k mod(N.sub.SS) equation[11]
where k.sub.i may represent an index for a bit assigned to the
i.sup.th spatial stream, floor(x) may represent an integer value
that is not larger than the value x, and y mod(x) may represent the
modulus x value for y.
[0057] The frequency interleaver block 306a may comprise suitable
logic, circuitry, and/or code that may enable a rearrangement of an
order of bits among a block of bits associated with a received
spatial stream. The frequency interleaver block 306a may utilize a
plurality of permutations when rearranging the order of bits among
a block of bits associated with a received spatial stream. After
rearrangement, the interleaved block of bits associated with the
i.sup.th spatial stream, b.sub.st[i].sup.int, may be divided into a
plurality of sub-blocks, b.sub.sub[f], where the index f may
represent a frequency. The frequency may correspond to one of a
plurality of frequency carriers that may be utilized to transmit a
representation of the bits contained in the sub-block via a
wireless communication medium, for example. The representation of
the bits may be referred to as a symbol. Each sub-block,
b.sub.sub[f], may comprise a portion of bits in the block
b.sub.st[i].sup.int. The block of bits b.sub.st[i].sup.int may
comprise the plurality of bits collectively contained in the
corresponding plurality of sub-blocks b.sub.sub[f].
[0058] The frequency interleaver block 306n may comprise suitable
logic, circuitry, and/or code that may enable a rearrangement of an
order of bits among a block of bits associated with a received
spatial stream, substantially as described for the frequency
interleaver block 306a. In various embodiments of the invention,
the number of frequency interleaver blocks 306a . . . 306n may
equal the number of spatial streams, N.sub.SS, for example.
[0059] The constellation mapper block 308a may comprise suitable
logic, circuitry, and/or code that may enable a mapping of received
bits, associated with a spatial stream, to one or more symbols. The
received bits may be encoded based on an FEC, for example, and may
be referred to as coded bits. The constellation mapper block 308a
may receive one or more coded bits, b.sub.sym[f], and generate the
symbol, sym[f], based on a modulation type associated with the
spatial stream. The number of coded bits associated with
b.sub.sym[f] may be determined based on the modulation type. The
representation of the symbol, sym[f], may be a complex quantity
comprising in-phase (I) and quadrature (Q) components. Each symbol,
sym[f.sub.k], associated with the one or more coded bits
b.sub.sym[f.sub.k] may be associated with a frequency carrier,
f.sub.k, where k may be an index that identifies a frequency
associated with a k.sup.th frequency carrier, utilized for
transmitting a representation of the symbol via the wireless
communication medium.
[0060] Exemplary modulation types may comprise binary phase shift
keying (BPSK), Quadra phase shift keying (QPSK), 16 level QAM (16
QAM), 64 level QAM (64 QAM), and 256 level QAM (256 QAM). For the
BPSK modulation type, the number of coded bits associated with a
symbol may be represented: b.sub.sym[f.sub.k]=1, for each frequency
carrier f.sub.k. For the QPSK modulation type, the number of coded
bits associated with a symbol may be represented:
b.sub.sym[f.sub.k]=2, for each frequency carrier f.sub.k. For the
16 QAM modulation type, the number of coded bits associated with a
symbol may be represented: b.sub.sym[f.sub.k]=4, for each frequency
carrier f.sub.k. For the 64 QAM modulation type, the number of
coded bits associated with a symbol may be represented:
b.sub.sym[f.sub.k]=6, for each frequency carrier f.sub.k. For the
256 QAM modulation type, the number of coded bits associated with a
symbol may be represented: b.sub.sym[f.sub.k]=8, for each frequency
carrier f.sub.k.
[0061] The spatial stream may comprise a plurality of frequency
carriers, N.sub.SD, for example a 20 MHz RF channel may comprise
N.sub.SD=56 frequency carriers, f.sub.-28, f.sub.-27, . . . ,
f.sub.-1, f.sub.1, . . . , f.sub.27, and f.sub.28, that may be
utilized for transmitting coded bits, while a 40 MHz RF channel may
comprise N.sub.SD=112 frequency carriers, f.sub.-56, f.sub.-55, . .
. , f.sub.-1, f.sub.1, . . . , f.sub.55, and f.sub.56, that may be
utilized for transmitting coded bits. In a MIMO system, the symbols
sym[f.sub.-28], sym[f.sub.-27], . . . , sym[f.sub.-1],
sym[f.sub.1], . . . , sym[f.sub.27], and sym[f.sub.28], or
sym[f.sub.-56], sym[f.sub.-55], . . . , sym[f.sub.-1],
sym[f.sub.1], . . . , sym[f.sub.55], and sym[f.sub.56], may be
collectively referred to as an orthogonal frequency division
multiplexing (OFDM) symbol. The number of coded bits associated
with an OFDM symbol, N.sub.CBPS=N.sub.SD*b.sub.sym[f.sub.k]. The
number of data bits associated with the OFDM symbol,
N.sub.DBPS=R*N.sub.SD*b.sub.sym[f.sub.k], where R may refer to the
coding rate.
[0062] The constellation mapper block 308n may comprise suitable
logic, circuitry, and/or code that may enable a mapping of received
bits, associated with a spatial stream, to one or more symbols,
substantially as described for the constellation mapper block 308a.
In various embodiments of the invention, the number of
constellation mapper blocks 308a . . . 308n may equal the number of
spatial streams, N.sub.ss, for example.
[0063] The serial to parallel block 309a may comprise suitable
logic, circuitry, and/or code that may enable serial reception of a
plurality of bits, and subsequent simultaneous output of the
serially received plurality of bits. The serial to parallel block
309a may comprise suitable memory, latches, and/or registers to
enable the serial to parallel function.
[0064] The serial to parallel block 309n may comprise suitable
logic, circuitry, and/or code that may enable serial reception of a
plurality of bits, and subsequent simultaneous output of the
serially received plurality of bits, substantially as described for
the serial to parallel block 309a. In various embodiments of the
invention, the number of serial to parallel blocks 309a . . . 309n
may equal the number of spatial streams, N.sub.SS, for example.
[0065] The beamforming V matrix block 312 may comprise suitable
logic, circuitry, and/or code that may enable processing of a
received plurality of spatial streams, generation of a
corresponding plurality of signals that may be simultaneously
transmitted by a MIMO transmitter 202, whereby a MIMO receiver 222
may receive the information contained in the plurality of spatial
streams. Each of the generated corresponding plurality of signals
may comprise at least one weighted sum of at least a portion of the
received plurality of spatial streams. A weighted sum may be
computed corresponding to each of the plurality of frequency
carriers, f.sub.k. The beamforming V matrix block 312 may generate
the corresponding plurality of signals based on a beamforming
matrix V.
[0066] The beamforming V matrix block 312 may receive a plurality
of spatial streams, s.sub.i, where i may represent an index that
indicates an i.sup.th spatial stream. Each of the spatial streams
may comprise a plurality of frequency components, s.sub.i[f.sub.k],
which correspond to each of the plurality of N.sub.SD frequency
carriers associated with the spatial stream s.sub.1. The plurality
of spatial streams may be represented by a plurality of matrices
S.sub.s[f.sub.k] as in the following equation:
S s [ f k ] = [ s 0 [ f k ] s 1 [ f k ] s N SS - 1 [ f k ] ]
equation [ 12 ] ##EQU00008##
where the frequency index k comprises values -28.ltoreq.k.ltoreq.28
for a 20 MHz RF channel, and -56.ltoreq.k.ltoreq.56 for a 40 MHz RF
channel.
[0067] The beamforming V[f.sub.k] matrix may comprise a plurality
of beamforming factors, V.sub.m,n[f.sub.k], where m represents a
row index in the matrix, and n represents a column index. The
beamforming V.sub.m,n[f.sub.k] matrix may be represented as in the
following equation:
equation [ 13 ] ##EQU00009## V [ f k ] = [ V 0 , 0 [ f k ] V 0 , 1
[ f k ] V 0 , N SS - 1 [ f k ] V 1 , 0 [ f k ] V 1 , 1 [ f k ] V 1
, N SS - 1 [ f k ] V N TX - 1 , 0 [ f k ] V N TX - 1 , 1 [ f k ] V
N TX - 1 , N SS - 1 [ f k ] ] ##EQU00009.2##
where N.sub.TX represents the number of generated signals, and the
frequency index k comprises values -28.ltoreq.k.ltoreq.28 for a 20
MHz RF channel, and -56.ltoreq.k.ltoreq.56 for a 40 MHz RF channel.
A value N.sub.TX=3 may indicate a MIMO transmitter 202 that
generates 3 transmitted signals.
[0068] Based on the representations of the received plurality of
spatial streams, and beamforming matrix, the plurality of generated
signals, X[f.sub.k], may be represented as in the following
equation:
X[f.sub.k]=V[f.sub.k]S.sub.S[f.sub.k] equation[14]
where the frequency index k comprises values -28.ltoreq.k.ltoreq.28
for a 20 MHz RF channel, and -56.ltoreq.k.ltoreq.56 for a 40 MHz RF
channel
[0069] The IFFT block 310a may comprise suitable logic, circuitry,
and/or code that may be utilized to enable conversion of a
frequency domain representation of a signal X[f] to a time domain
representation X(t). The corresponding time domain signal may
comprise a plurality of OFDM symbols. An OFDM symbol may be
computed based on application of an IFFT algorithm to the frequency
components associated with the corresponding signal X[f]. For
example a 64 point IFFT algorithm may be utilized by the IFFT block
310a when processing a 20 MHz RF channel, while a 128 point IFFT
algorithm may be utilized when processing a 40 MHz RF channel. An
exemplary method for OFDM symbol computation may be found in clause
17.3.5.9 from the IEEE standard 802.11a-1999 (R 2003).
[0070] The time domain representation X(t) may comprise time domain
representations for a plurality of signals, x.sub.j(t), that may be
transmitted simultaneously by a MIMO transmitter 202 as shown in
the following equation:
X ( t ) = [ x 0 ( t ) x 1 ( t ) x N TX - 1 ( t ) ] equation [ 15 ]
##EQU00010##
[0071] Each of the plurality of signals x.sub.j(t) may comprise a
plurality of OFDM symbols associated with an j.sup.th signal among
a plurality of N.sub.TX simultaneously transmitted signals from a
MIMO transmitter 302. The OFDM symbols transmitted within the
j.sup.th signal, x.sub.j(t), among a plurality of N.sub.TX
simultaneously transmitted signals may be transmitted serially in
time. Each OFDM symbol may span a time duration, T.sub.SYM,
referred to as a symbol interval, for example T.sub.SYM=4
.mu.s.
[0072] The IFFT block 310n may comprise suitable logic, circuitry,
and/or code that may be utilized to enable conversion of a
frequency domain representation of a signal X[f] to a time domain
representation X(t), substantially as described for the IFFT block
310a. In various embodiments of the invention, the number of IFFT
blocks 310a . . . 310n may equal the number of generated signals
N.sub.TX, for example.
[0073] The insert GI window block 311a may comprise suitable logic,
circuitry, and/or code that may be utilized to enable insertion of
guard intervals in one of a plurality of signals x.sub.j(t)
transmitted by a MIMO transmitter 302. The guard interval,
T.sub.GI, may represent a time interval between the end of a
current OFDM symbol interval, and the beginning of a subsequent
OFDM symbol interval. Subsequent to the end of a symbol interval
associated with a current OFDM symbol may follow a guard interval
time duration, T.sub.GI, for example T.sub.GI=0.8 .mu.s. Following
the guard interval time duration a subsequent symbol interval
corresponding to a subsequent OFDM symbol may follow.
[0074] The insert GI window block 311n may comprise suitable logic,
circuitry, and/or code that may be utilized to enable insertion of
guard intervals in one of a plurality of signals x.sub.j(t)
transmitted by a MIMO transmitter 302, substantially as described
for the insert GI window block 311a. In various embodiments of the
invention, the number of insert GI window blocks 311a . . . 311n
may equal the number of generated signals, N.sub.TX, for
example.
[0075] The RFE block 314a may comprise suitable, logic, circuitry,
and/or code that may be utilized to enable generation of an RF
signal from a received generated signal. The RF block 314a may
receive a generated baseband signal. The RFE block 314a may
generate the RF signal by utilizing a plurality of frequency
carrier signals to modulate the received baseband signal. The
modulated signal may be transmitted via the antenna 315a. The RFE
block 314a may be utilized to enable generation of a 20 MHz RF
signal, or of a 40 MHz RF signal, for example.
[0076] The RFE block 314n may comprise suitable, logic, circuitry,
and/or code that may be utilized to enable generation of an RF
signal from a received generated signal, substantially as described
for the RFE block 314a. The modulated signal generated by the RFE
block 314n may be transmitted via the antenna 315n. In various
embodiments of the invention, the number of RFE blocks 314a . . .
314n may equal the number of generated signals, N.sub.TX, for
example.
[0077] The processor 342 may comprise suitable logic, circuitry,
and/or code that may be utilized to enable a classification of
source information bits. The processor 342 may enable the
computation of values corresponding to beamforming factors,
V.sub.m,n[f.sub.k], based on the classification. The beamforming
factor V.sub.m,n[f.sub.k] may correspond to an m.sup.th
transmitting antenna, and an n.sup.th spatial stream. The
beamforming factors may determine a number of transmitting antennas
212, 214, 216 utilized, and at least one power level and/or phase,
with which the spatial stream may be transmitted via a wireless
medium from a transmitting MIMO system 202, to a receiving MIMO
system 222. Based on the classification, source information bits
may be assigned an n.sup.th spatial stream, wherein a beamforming
factor V.sub.m,n[f.sub.k] may be utilized when transmitting the
source information via an m.sup.th transmitting antenna.
[0078] The processor 342 may also enable the transmitter 300 to
perform transmitter functions in accordance with applicable
communications standards. These function may comprise, but are not
limited to, tasks performed at lower layers, for example physical
layer (PHY) and medium access control (MAC) layer functions, in a
relevant protocol reference model. These tasks may comprise
physical layer functions, such as physical layer convergence
protocol (PLCP), physical medium dependent (PMD), and/or associated
layer management functions, for example. The processor 342 may also
enable generation of source information bits and/or retrieval of
stored source information that may be subsequently classified,
coded, mapped, and transmitted via the wireless medium, for
example.
[0079] The memory 340 may comprise suitable logic, circuitry,
and/or code that may be utilized to enable storage and/or retrieval
of information and/or a representation of the information, for
example a binary representation comprising bits. The memory 340 may
enable storage of source information bits. The stored source
information bits may be assigned physical resources within the
memory 340 for the storage. The stored source information bits may
be subsequently available for retrieval. Retrieved source
information bits may be output by the memory 340 and communicated
to other devices, components, and/or subsystems that may be
communicatively coupled, directly and/or indirectly, to the memory
340. The memory 340 may enable the stored source information bits
to remain stored and/or available for subsequent retrieval until
the resources allocated for the storage are deallocated. Physical
resources may be deallocated based on a received instruction that
the stored source information bits be erased from the memory 340,
or based on a received instruction that the physical resources be
allocated for the storage of subsequent binary information. The
memory 340 may utilize a plurality of storage medium technologies
such as volatile memory, for example random access memory (RAM),
and/or nonvolatile memory, for example electrically erasable
programmable read only memory (EEPROM).
[0080] In operation the processor 342 may enable the communication
of instructions to the memory 340. The instructions may enable the
retrieval of stored multimedia information from the memory 340. The
multimedia information may comprise voice, video, and/or data
information. The processor 342 may categorize the retrieved
multimedia information based on content. For example, the retrieved
multimedia information may be categorized by priority class, such
as high priority, medium priority, or low priority.
[0081] In one exemplary embodiment of the invention, the retrieved
multimedia information may comprise MPEG-1, or MPEG-2 encoded video
information. The MPEG video information may be categorized based on
whether the content is associated with an I-frame, a B-frame, or a
P-frame, for example. I-frame information may be categorized as
high priority, B-frame information may be categorized as medium
priority, and P-frame information may be categorized as low
priority, for example.
[0082] In another exemplary embodiment of the invention, the
retrieved multimedia information may comprise MPEG-4 encoded
information. The MPEG-4 encoded information may comprise a
plurality of objects, and scene descriptor information that enables
the plurality of objects to be arranged in one or more video
frames, for example. The MPEG-4 encoded information may be
categorized based on whether the content is scene descriptor
information, a background object, or foreground object, for
example. Scene descriptor information, and information relating to
foreground objects may be categorized as high priority, and
information relating to background objects may be categorized as
low priority, for example.
[0083] The categorized retrieved multimedia information may be
communicated by the memory 340 to the channel encoder block 302.
The retrieved multimedia information may be communicated to the
channel encoder block 302 as one or more binary input data blocks.
Individual data blocks may be presented as input to the channel
encoder blocks serially at distinct time instants. Each data block
may comprise a plurality of bits. The bits contained within a given
data block may be categorized to belong to a plurality of priority
classes.
[0084] The spatial parser block 305 may parse the coded data block
to generate a plurality of parsed data blocks. A parsed data block
among the plurality of parsed data blocks may comprise at least a
portion of the bits contained in the coded data block. A bit from
the coded data block may be assigned to a given parsed data block
based on the priority class associated with the bit. Each of the
parsed data blocks generated from a coded data block may comprise
spatial stream data that may be associated with a corresponding
spatial stream. Each of the parsed data blocks may be associated
with one of a plurality of spatial streams based on the
corresponding priority class.
[0085] Any of the plurality of frequency interleaver blocks 306a .
. . 306n may rearrange the order of bits in a received parsed data
block for the corresponding spatial stream. Each of the frequency
interleaver blocks 306a . . . 306n may generate an interleaved
spatial stream block.
[0086] Any of the plurality of constellation mapper blocks 308a . .
. 308n may map at least a portion of bits contained in a received
interleaved spatial stream block to generate a symbol. Each of the
constellation mapper blocks 308a . . . 308n may perform its
respective mapping operation by utilizing a modulation type.
[0087] Any of the plurality of serial to parallel blocks 309a . . .
309n may convert a bit serial representation of the symbol,
generated in the corresponding spatial stream, to a bit parallel
symbol representation comprising a plurality of simultaneously
output bits. Relating FIG. 2 to FIG. 3, the plurality of bit
parallel symbol representations generated by the corresponding
plurality of serial to parallel blocks 309a . . . 309n may
correspond to the plurality of source signals 206, 208, and 210, as
represented in equation[1c].
[0088] The beamforming V matrix 312 may perform beamforming to
generate a plurality of transmit signals based on the received
plurality of bit parallel symbols. The processor 342 may determine
values for individual beamforming factors V.sub.m,n[f.sub.k] for
each of the frequency carriers associated with an RF channel. The
values may be determined based on the priority class associated
with the corresponding spatial stream. In various embodiments of
the invention in which an SVD method is utilized, the values for
individual beamforming factors V.sub.m,n[f.sub.k] may be computed
based on the relationship shown in equations[4] and [8], for
example. In the various embodiments of the invention, there may be
a plurality of diagonal matrices, which correspond to the plurality
of frequency carriers associated with an RF channel as in the
following equation:
D [ f k ] = [ .lamda. 1 , 1 [ f k ] 0 0 0 .lamda. 2 , 2 [ f k ] 0 0
0 0 0 .lamda. A , A [ f k ] ] equation [ 16 ] ##EQU00011##
where the frequency index k comprises values -28.ltoreq.k.ltoreq.28
for a 20 MHz RF channel, and -56.ltoreq.k.ltoreq.56 for a 40 MHz RF
channel
[0089] In various embodiments of the invention, a signal strength
measure may be associated with a spatial stream such that a given
spatial stream may be referred to as being "stronger" than at least
a portion of the remaining spatial streams among the plurality of
spatial streams. The signal strength measure may correspond to
values associated with the plurality of diagonal matrices as shown
in equation[16], for example. The spatial streams may be associated
with a corresponding signal strength measure, and at least a
portion of the source information bit data may be assigned to one
or more spatial streams based on the associated priority class.
Data associated with higher priority classes may be assigned to
stronger spatial streams, in comparison with data associated with
lower priority classes, which may be assigned to weaker spatial
streams, for example. Relating FIG. 2 to FIG. 3, the plurality of
transmit signals generated by the beamforming V matrix 312 may
correspond to the plurality of source signals x.sub.1, x.sub.2, and
x.sub.3, as represented in equation[1b].
[0090] Any among the plurality of IFFT blocks 310a . . . 310n may
convert a frequency domain representation signal, generated for a
corresponding transmit signal, to a corresponding time domain
representation. Any of the plurality of insert GI window blocks
311a . . . 311n may insert guard intervals in a corresponding
transmit signal. Any of the plurality of RFE blocks 314a . . . 314n
may generate an RF signal, for a corresponding transmit signal,
which may be transmitted via a wireless communications medium via a
corresponding one of the plurality of transmitting antennas 315a .
. . 315n.
[0091] FIG. 4 is a flowchart illustrating exemplary steps for
content aware mapping and error protection using different spatial
streams, in accordance with an embodiment of the invention.
Referring to FIG. 4, in step 402 a plurality of priority classes
may be assigned to source information bits. The priority classes
may be defined based on the content associated with the source
information bits. In step 404, beamforming factors may be computed
based on the plurality of priority classes. In step 406, source
information bits maybe assigned to one of a plurality of spatial
streams based on the plurality of priority classes. In step 408,
coded, mapped, and beamformed source information bits may be
transmitted by utilizing a plurality of spatial streams based on
the assigned priority class.
[0092] Aspects of a system for handling multimedia information in a
communication system may comprise a transmitter 300 that enables
control of a MAC layer and/or a PHY layer, in a wireless
communication device to wirelessly communicate different portions
of multimedia information via different spatial streams based on
content of the multimedia information. The system may also comprise
a processor 342 that enables definition of a plurality of priority
classes based on the content associated with at least a portion of
the multimedia information.
[0093] In another aspect, the system may comprise a channel encoder
302 that enables coding of at least a portion of the multimedia
information. The system may also comprise a spatial parser 305 that
enables assignment of at least a portion of the coded portion of
the multimedia information to one of the different spatial streams
based on the corresponding one of the plurality of priority
classes. The system may also comprise a plurality of constellation
mappers 306a . . . 306n that enable mapping of the assigned portion
or more of the coded portion or more of the multimedia information
based on a modulation type.
[0094] In various embodiments of the invention, the processor 342
may enable computation of a plurality of multiplicative factors for
a corresponding plurality of frequency carriers associated with at
least a portion of the different spatial streams based on the
plurality of priority classes. The multiplicative factors may
comprise beamforming factors. The system may comprise a beamforming
V matrix 312 that enables generation of a transmitted signal by
combining at least a portion of the different spatial streams. The
combining among the portions of the different spatial streams may
be based on the plurality of priority classes.
[0095] Accordingly, the present invention may be realized in
hardware, software, or a combination of hardware and software. The
present invention may be realized in a centralized fashion in at
least one computer system, or in a distributed fashion where
different elements are spread across several interconnected
computer systems. Any kind of computer system or other apparatus
adapted for carrying out the methods described herein is suited. A
typical combination of hardware and software may be a
general-purpose computer system with a computer program that, when
being loaded and executed, controls the computer system such that
it carries out the methods described herein.
[0096] The present invention may also be embedded in a computer
program product, which comprises all the features enabling the
implementation of the methods described herein, and which when
loaded in a computer system is able to carry out these methods.
Computer program in the present context means any expression, in
any language, code or notation, of a set of instructions intended
to cause a system having an information processing capability to
perform a particular function either directly or after either or
both of the following: a) conversion to another language, code or
notation; b) reproduction in a different material form.
[0097] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
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