U.S. patent application number 13/439350 was filed with the patent office on 2012-08-02 for method and apparatus for reducing the processing rate of a chip-level equalization receiver.
This patent application is currently assigned to INTERDIGITAL TECHNOLOGY CORPORATION. Invention is credited to Jung-Lin Pan.
Application Number | 20120195358 13/439350 |
Document ID | / |
Family ID | 36316291 |
Filed Date | 2012-08-02 |
United States Patent
Application |
20120195358 |
Kind Code |
A1 |
Pan; Jung-Lin |
August 2, 2012 |
METHOD AND APPARATUS FOR REDUCING THE PROCESSING RATE OF A
CHIP-LEVEL EQUALIZATION RECEIVER
Abstract
A method and apparatus for reducing the processing rate when
performing chip-level equalization (CLE) in a code division
multiple access (CDMA) receiver which includes an equalizer filter.
Signals received by at least one antenna of the receiver are
sampled at M times the chip rate. Each sample stream is split into
M sample data streams at the chip rate. Multipath combining is
preferably performed on each split sample data stream. The sample
data streams are then combined into one combined sample data stream
at the chip rate. The equalizer filter performs equalization on the
combined sample stream at the chip rate. Filter coefficients are
adjusted by adding a correction term to the filter coefficients
utilized by the equalizer filter for a previous iteration.
Inventors: |
Pan; Jung-Lin; (Smithtown,
NY) |
Assignee: |
INTERDIGITAL TECHNOLOGY
CORPORATION
Wilmington
DE
|
Family ID: |
36316291 |
Appl. No.: |
13/439350 |
Filed: |
April 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13099674 |
May 3, 2011 |
8170083 |
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13439350 |
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|
12535010 |
Aug 4, 2009 |
7936807 |
|
|
13099674 |
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|
11824792 |
Jul 2, 2007 |
7573963 |
|
|
12535010 |
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|
11515169 |
Sep 1, 2006 |
7257152 |
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|
11824792 |
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11210591 |
Aug 24, 2005 |
7116705 |
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11515169 |
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60625870 |
Nov 8, 2004 |
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Current U.S.
Class: |
375/229 |
Current CPC
Class: |
H04B 1/7115 20130101;
H04L 25/03038 20130101; H04L 2025/03617 20130101; H04L 2025/03477
20130101; H04B 1/70757 20130101; H04B 2201/70707 20130101; H04B
1/707 20130101; H04L 2025/03375 20130101 |
Class at
Publication: |
375/229 |
International
Class: |
H04L 27/01 20060101
H04L027/01; H04B 1/06 20060101 H04B001/06 |
Claims
1. A code division multiple access (CDMA) receiver comprising: an
antenna component configured to receive a data signal associated
with a chip rate; circuitry configured to define a plurality of
streams of data samples corresponding to the received data signal
at the chip rate; a combiner component configured to combine the
plurality of streams of data samples into a data stream of combined
samples at the chip rate; and a one times chip rate normalized
least mean square (NLMS) equalizer configured to equalize the data
stream of combined samples.
2. The receiver of claim 1 wherein: the circuitry configured to
define a plurality of streams of data samples includes: a sampling
device configured to sample the received data signal at a multiple
M of the chip rate, where M is an integer greater than 1, to
produce an over-sampled stream of data samples; and a
serial-to-parallel (S/P) converter configured to split the
over-sampled stream of data samples into M streams of data samples;
and the combiner component is configured to combine the M streams
of data samples in connection with producing the data stream of
combined samples at the chip rate.
3. The receiver of claim 2 wherein: the antenna component is
configured as a single antenna; the sampling device is configured
to sample the received data signal that is received by the antenna
at twice the chip rate; and the serial-to-parallel (S/P) converter
is configured to split the over-sampled stream of data samples into
even and odd streams of data samples.
4. The receiver of claim 2 wherein the combiner component includes:
M multipath combiners, each configured to combine multipath or
delayed replicates of signal samples with respect to a respective
stream of data samples of the M streams of data samples to produce
a combined multipath version of the respective stream of data
samples; and an over-sample combiner configured to combine the
combined multipath versions of the M streams of data samples in
connection with producing the data stream of combined samples at
the chip rate.
5. The receiver of claim 4 wherein: the antenna component is
configured as a single antenna; the sampling device is configured
to sample the received data signal that is received by the antenna
at twice the chip rate; and the serial-to-parallel (S/P) converter
is configured to split the over-sampled stream of data samples into
even and odd streams of data samples.
6. The receiver of claim 1 wherein: the antenna component is
configured with N antennas; the circuitry configured to define a
plurality of streams of data samples includes: N sampling devices,
each configured to sample the received data signal as received from
a respective one of the N antennas at a multiple M of the chip
rate, where M is an integer greater that 1, such that the N
sampling devices produce N respective over-sampled streams of data
samples; and N serial-to-parallel (S/P) converters, each configured
to split a respective over-sampled stream of data samples into M
streams of data samples; and the combiner component includes: N
combiners, each configured to combine the M streams of data samples
derived from a respective over-sampled stream of data samples such
that the N combiners produce N combined data streams, and a
diversity data stream combiner configured to combine the N combined
data streams in connection with producing the data stream of
combined samples at the chip rate.
7. The receiver of claim 6 wherein: each sampling device is
configured to sample the received data signal that is received by a
respective antenna at twice the chip rate; and each
serial-to-parallel (S/P) converter is configured to split the
respective over-sampled stream of data samples into even and odd
streams of data samples.
8. The receiver of claim 7 wherein the antenna component is
configured with two (2) antennas.
9. The receiver of claim 6 wherein: each of the N combiners
includes: M multipath combiners, each configured to combine
multipath or delayed replicates of signal samples with respect to a
respective stream of data samples of the respective M streams of
data samples to produce a combined multipath version of the
respective stream of data samples; and an over sample combiner
configured to combine the combined multipath versions of the M
streams of data samples such that each of the N combiners produces
a respective over-sampled combined multipath versions of a
respective over-sampled streams of data; and the diversity data
stream combiner is configured to combine the N over-sampled
combined multipath versions of the N over-sampled streams of data
in connection with producing the data stream of combined samples at
the chip rate.
10. The receiver of claim 9 wherein: each sampling device is
configured to sample the received data signal that is received by a
respective antenna at twice the chip rate; and each
serial-to-parallel (S/P) converter is configured to split the
respective over-sampled stream of data samples into even and odd
streams of data samples.
11. The receiver of claim 10 wherein the antenna component is
configured with two (2) antennas.
12. A wireless communication apparatus comprising the receiver of
claim 1.
13. A method of equalizing received data signals in a code division
multiple access (CDMA) wireless communications comprising:
receiving a data signal associated with a chip rate; defining a
plurality of streams of data samples corresponding to the received
data signal at the chip rate; combining the plurality of streams of
data samples into a data stream of combined samples at the chip
rate; and using a one times chip rate normalized least mean square
(NLMS) equalizer to equalize the data stream of combined
samples.
14. The method of claim 13 wherein: the defining a plurality of
streams of data samples includes: sampling the received data signal
at a multiple M of the chip rate, where M is an integer greater
than 1, to produce an over-sampled stream of data samples; and
splitting the over-sampled stream of data samples into M streams of
data samples; and the combining includes combining the M streams of
data samples in connection with producing the data stream of
combined samples at the chip rate.
15. The method of claim 14 wherein the combining includes: for each
of the M streams of data samples, combining multipath or delayed
replicates of signal samples to produce a combined multipath
version of the respective stream of data samples; and combining the
combined multipath versions of the M streams of data samples in
connection with producing the data stream of combined samples at
the chip rate.
16. The method of claim 15 wherein: the sampling the received data
signal is at twice the chip rate; and the over-sampled stream of
data samples is split into even and odd streams of data
samples.
17. The method of claim 13 wherein: the defining a plurality of
streams of data samples includes: with respect to each of N
versions of the data signal received by a different one of N
antennas, sampling the received data signal at a multiple M of the
chip rate, where M is an integer greater than 1, such that N
respective over-sampled streams of data samples are produced; and
splitting each respective over-sampled stream of data samples into
a set of M streams of data samples; and the combining includes:
with respect to each set of M streams of data samples, combining
the M of streams of data samples derived from a respective
over-sampled stream of data samples such that N combined data
streams are produced, and diversity combining the N combined data
streams in connection with producing the data stream of combined
samples at the chip rate.
18. The method of claim 17 wherein: the combining with respect to
each set of M streams of data samples includes: for each of the M
streams of data, combining multipath or delayed replicates of
signal samples to produce a combined multipath version of the
respective stream of data samples; and over sample combining the
combined multipath versions of the M of streams of data samples
such that a respective over-sampled combined multipath versions of
a respective over-sampled streams of data is produced; and the
diversity combining includes combining the over-sampled combined
multipath versions of the N over-sampled streams of data in
connection with producing the data stream of combined samples at
the chip rate.
19. The method of claim 18 wherein: each version of the received
data signal is sampled at twice the chip rate; and each respective
over-sampled stream of data samples is split into even and odd
streams of data samples.
20. The method of claim 19 performed with respect to a version of
the received signal with respect to two (2) antennas.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/099,674, filed May 3, 2011, which is a
continuation of U.S. patent application Ser. No. 12/535,010, filed
Aug. 4, 2009 which issued as U.S. Pat. No. 7,936,807 on May 3,
2011, which is a continuation of U.S. patent application Ser. No.
11/824,792, filed Jul. 2, 2007, which issued as U.S. Pat. No.
7,573,963 on Aug. 11, 2009, which is a continuation of U.S. patent
application Ser. No. 11/515,169, filed Sep. 1, 2006, which issued
as U.S. Pat. No. 7,257,152 on Aug. 14, 2007, which is a
continuation of U.S. patent application Ser. No. 11/210,591 filed
Aug. 24, 2005, which issued as U.S. Pat. No. 7,116,705 on Oct. 3,
2006, which in turn claims the benefit of U.S. Provisional Patent
Application No. 60/625,870, filed Nov. 8, 2004, all of which are
incorporated by reference as if fully set forth.
FIELD OF THE INVENTION
[0002] The present invention relates to a code division multiple
access (CDMA) receiver. More particularly, the present invention
relates to a method and apparatus for reducing the processing rate
when performing chip-level equalization (CLE) in the CDMA
receiver.
BACKGROUND
[0003] Chip-level equalizers are suitable candidates for CDMA
receivers, such as those used in wireless transmit/receive units
(WTRUs) and base stations. A normalized least mean square
(NLMS)-based CLE receiver offers superior performance for high data
rate services such as high speed downlink packet access (HSDPA)
over a Rake receiver. A typical NLMS receiver consists of an
equalizer filter and an NLMS algorithm. The equalizer filter is
typically a finite impulse response (FIR) filter.
[0004] The NLMS algorithm is used as the tap coefficients
generator. It generates appropriate tap coefficients used by the
equalizer filter and updates them appropriately and iteratively in
a timely basis. Typically, tap coefficients generation includes the
error signal computation, vector norm calculation and leaky
integration to generate and update the tap coefficients.
[0005] The high complexity of the CLE is due to the over-sampling
processing in the CLE. A typical CLE includes equalizer filtering,
tap-weight vector updating, vector norm square computing, or the
like, which all operate at two or more times the chip rate. Two
times the chip rate over-sampling processing induces twice as much
complexity as the chip rate non-over-sampling processing in the
equalizer filter.
SUMMARY
[0006] The present application is related to a method and apparatus
for reducing the processing rate when performing CLE in a CDMA
receiver which includes an equalizer filter. Signals received by at
least one antenna of the receiver are sampled at M times the chip
rate, where M is a positive integer. Each sample stream is split
into M sample data streams at the chip rate. Multipath combining is
preferably performed on each split sample data stream. The sample
data streams are then combined into one combined sample data stream
at the chip rate. The equalizer filter performs equalization on the
combined sample stream at the chip rate. Filter coefficients are
adjusted by adding a correction term to the filter coefficients
utilized by the equalizer filter for a previous iteration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] A more detailed understanding of the invention may be had
from the following description, given by way of example and to be
understood in conjunction with the accompanying drawings
wherein:
[0008] FIG. 1 is a block diagram of an exemplary CDMA receiver
configured in accordance with a first embodiment;
[0009] FIG. 2 is a block diagram of an exemplary CDMA receiver
configured in accordance with a second embodiment;
[0010] FIGS. 3A and 3B, taken together, are a block diagram of an
exemplary CDMA receiver configured in accordance with a third
embodiment; and
[0011] FIG. 4 is a flow diagram of a process for implementing
non-over-sampling processing in a CDMA receiver.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The preferred embodiments will be described with reference
to the drawing figures where like numerals represent like elements
throughout.
[0013] Hereafter, the terminology "WTRU" includes but is not
limited to a user equipment (UE), a mobile station, a laptop, a
personal data assistant (PDA), a fixed or mobile subscriber unit, a
pager, or any other type of device capable of operating in a
wireless environment. When referred to hereafter, the terminology
"base station" includes but is not limited to an access point (AP),
a Node-B, a site controller or any other type of interfacing device
in a wireless environment.
[0014] The features of the present invention may be incorporated
into an integrated circuit (IC) or be configured in a circuit
comprising a multitude of interconnecting components.
[0015] Hereafter, the present invention will be explained with
reference to an NLMS algorithm. However, it should be noted that
any type of adaptive equalization or filtering, such as least mean
square (LMS), Griffith's algorithm, channel estimation based NLMS
(CE-NLMS), and other iterative or recursive algorithms may be
used.
[0016] FIG. 1 is a block diagram of an exemplary CDMA receiver 100
configured in accordance with a first embodiment. The CDMA receiver
100 includes at least one antenna 102, a sampler 104, a
serial-to-parallel (S/P) converter 106, two multipath combiners
108A, 108B, an over-sample combiner 110 and a 1.times. chip rate
non-over-sample processing NLMS equalizer 112. The NLMS equalizer
112 includes an equalizer filter 114 and a tap coefficients
generator 116.
[0017] Signals are received by the antenna 102 and are sampled by
the sampler 104 at twice the chip rate. The sampler 104 outputs a
sample data stream 105, which is split into an odd sample data
stream 107A and an even sample data stream 107B by the S/P
converter 106. Therefore, the chip rate of signals output by the
S/P converter 106 is one times (1.times.) the chip rate.
[0018] The even and odd sample data streams 107A, 107B are fed into
respective ones of the multipath combiners 108A, 108B. Multipath is
the signal spread in the time domain due to reflection of the
signal from objects. The same signal may arrive at the receiver at
different times (due to reflection), either early or late
(depending on the reflection distances), and with different
amplitudes and phases due to fading. The multipath combiners 108A,
108B collect and combine an original signal with their delayed
spread signal (multipath signal or delayed replicates) to improve
the reception quality. Each of the sample data streams 107A, 107B
has one sample stream and one or more delayed sample streams. The
number of delayed sample data streams depends on the number of
multipaths that the original signal experienced.
[0019] The multipath combiners 108A, 108B combine the multipath or
delayed replicates of the signal data streams 107A, 107B. Maximum
ratio combining (MRC) may be used for multipath combining. The
multipath combined signal data streams 109A, 109B output by the
respective multipath combiners 108A, 108B are then fed to an
over-sample combiner 110.
[0020] The over-sample combiner 110 combines the multipath combined
signal streams 109A, 109B and produces one combined sample data
stream 111 at one times (1.times.) the chip rate. The combined
sample stream 111 is fed into the equalizer filter 114 and the tap
coefficients generator 116.
[0021] A matched filter (MF) may be used as the multipath combiners
108A, 108B and the over-sample combiner 110. The parameters {right
arrow over (x)}.sub.n.sup.i,o, {right arrow over (x)}.sub.n.sup.i,e
and H.sup.i,o, H.sup.i,e are denoted as a received signal vector
and a channel response matrix for odd and even over-sampled
sequences, respectively. The vector {right arrow over (x)}.sub.n,co
is denoted as a combined signal vector after the multipath and
over-sample combining. Assuming that a matched filter is used for
multipath and over-sample combining, the combined signal can be
expressed as follows:
{right arrow over (x)}.sub.n,co=H.sup.1,o.sup.H{right arrow over
(x)}.sub.n.sup.1,o+H.sup.1,e.sup.H{right arrow over
(x)}.sub.n.sup.1,e+H.sup.2,o.sup.H{right arrow over
(x)}.sub.n.sup.2,o+H.sup.2,e.sup.H{right arrow over
(x)}.sub.n.sup.2,e. Equation (1)
[0022] After the signal combining is performed, one improved signal
stream 111 is formed and is fed to the equalizer filter 114 to
perform equalization to remove interference such as inter-symbol
interference (ISI) and multiple access interference (MAI). The
equalizer filter 114 is preferably a finite impulse response (FIR)
filter comprising a tap-delay line with tap coefficients of L taps.
The NLMS equalizer 112 may be described in terms of weight updates
as follows:
w -> n + 1 , co = .alpha. w -> n , co + .mu. x -> n , co *
x n , co 2 ( d [ n ] - x -> n , co T w -> n , co ) , Equation
( 2 ) ##EQU00001##
where {right arrow over (w)}.sub.n,co is the tap-weight vector and
d[n] is the reference signal at time n.
[0023] The equalizer filter 114 operates at 1.times. chip rate and
does not have over-sampling processing. Therefore, the number of
taps of the equalizer filter 114 is smaller than that is required
in a prior art equalizer filter with 2.times. chip rate processing.
The equalizer filter 114 requires only half of the number of taps
in the 2.times. chip rate equalizer filter.
[0024] The tap coefficients generator 116 includes multipliers 118,
124, an adder 130, a serial-to-parallel (S.fwdarw.P) to vector
converter 122, a vector accumulator 126, a correction term
generator 128 and a chips accumulator 132. The output from the
equalizer filter 114 is descrambled via the multiplier 118. The
output of the multiplier 118 is accumulated by the chips
accumulator 132 for a predetermined period (e.g., for chips equal
to a common pilot channel (CPICH) despreading factor). The
accumulated result output by the chips accumulator 132 is
subtracted from a reference pilot signal 129 via the adder 130 to
generate an error signal 131, represented by a variable e, which is
used by the correction term generator 128 to generate correction
terms 134.
[0025] The combined input sample data stream 111 is converted to
length L vectors by the S.fwdarw.P to vector converter 122 and
descrambled by the multiplier 124. The descrambled input vectors
are accumulated for a predetermined period, (e.g., for chips equal
to a CPICH despreading factor) by the vectors accumulator 126 to
generate update vectors 127. The update vectors 127 are forwarded
to the correction term generator 128. To generate correction terms
for tap coefficient updates, the inputs for .mu..sub.P, e, X.sub.ud
are required. .mu..sub.P is the step size. e is the error signal
which is the differential signal between an equalized signal and a
reference signal, which typically is used in the form of a pilot
signal. X.sub.ud is the received signal after descrambling and
despreading. .parallel.X.sub.ud.parallel..sup.2 is the norm of the
descrambled and despread signal X.sub.ud. Equation (2) is used for
iteration algorithm and tap coefficient updates.
[0026] The correction term generator 128 may generate the
correction terms 134 based on the correction term
.mu. P e X ud * X ud 2 ##EQU00002##
which is added, in the equalizer filter 114, to the filter
coefficients of the previous iteration to generate updated filter
coefficients for the next iteration.
[0027] Alternatively, the correction term generator 128 may
generate the correction terms 134 based on the correction term
.mu. P e X ud * X ud 2 + .eta. . ##EQU00003##
The variable .eta. is a relatively small number that is used to
improve the numerical properties and prevent the fixed-point
computation from overflow when the correction term is
generated.
[0028] FIG. 2 is a block diagram of an exemplary CDMA receiver 200
configured in accordance with a second embodiment. The CDMA
receiver 200 includes two antennas 202A, 202B, two samplers 204A,
204B, two S/P converters 206A, 206B, four multipath combiners 208A,
208B, 208C, 208D, two over-sample combiners 210A, 210B, an antenna
diversity combiner 212 and the 1.times. chip rate non-over-sample
processing NLMS equalizer 112 described above with respect to FIG.
1.
[0029] Signals are received by the antennas 202A, 202B and are
respectively sampled by the samplers 204A, 204B at twice (2.times.)
the chip rate. The sampler 204A outputs a sample data stream 205A,
which is split into an odd sample data stream 207A and an even
sample data stream 207B by the S/P converter 206A at one times
(1.times.) the chip rate. The sampler 204B outputs a sample data
stream 205B, which is split into an odd sample data stream 207C and
an even sample data stream 207D by the S/P converter 206B at one
times (1.times.) the chip rate.
[0030] The odd sample data stream 207A and the even sample data
stream 207B are fed into respective ones of the multipath combiners
208A, 208B. The multipath combiners 208A, 208B respectively combine
the multipath or delayed replicates of the signal data streams
207A, 207B. Maximum ratio combining (MRC) may be used for multipath
combining. The multipath combined signal data streams 209A, 209B
are output by the respective multipath combiners 208A, 208B at one
times (1.times.) the chip rate and are then fed to an over-sample
combiner 210A. The over-sample combiner 210A combines the multipath
combined signal streams 209A, 209B and produces a first combined
sample data stream 211A at one times (1.times.) the chip rate.
[0031] The odd sample data stream 207C and the even sample data
stream 207D are fed into respective ones of the multipath combiners
208C, 208D. The multipath combiners 208C, 208D respectively combine
the multipath or delayed replicates of the signal data streams
207C, 207D. MRC may be used for multipath combining. The multipath
combined signal data streams 209C, 209D are output by the
respective multipath combiners 208C, 208D at one times (1.times.)
the chip rate and are then fed to an over-sample combiner 210B. The
over-sample combiner 210B combines the multipath combined signal
streams 209C, 209D and produces a second combined sample data
stream 211B at one times (1.times.) the chip rate.
[0032] The combined sample data streams 211A and 211B are combined
by the antenna diversity combiner 212, and the combined output 214
of the antenna diversity combiner 212 is fed into the equalizer
filter 114 and the tap coefficients generator 116 of the 1.times.
chip rate non-over-sample processing NLMS equalizer 112.
[0033] FIGS. 3A and 3B, taken together, are a block diagram of an
exemplary CDMA receiver 300 configured in accordance with a third
embodiment. The third embodiment is an extension of the first and
second embodiments to N antennas and M.times. oversampling, where N
and M are positive integers. The CDMA receiver 300 includes N
antennas 302.sub.1-302.sub.N, N samplers 304.sub.1-304.sub.N, N S/P
converters 306.sub.1-306.sub.N (i.e., splitters), N.times.M
multipath combiners 308.sub.11-308.sub.NM, N over-sample combiners
310.sub.1-310.sub.N, an antenna diversity combiner 312 and the
1.times. chip rate non-over-sample processing NLMS equalizer 112
described above with respect to FIG. 1.
[0034] Signals are received by the antennas 302.sub.1-302.sub.N and
are respectively sampled by the samplers 304.sub.1-304.sub.N at M
times (M.times.) the chip rate (i.e., 1.sup.st sample sequence,
2.sup.nd sample sequence, . . . , the Mth sample sequence).
[0035] In response to receiving a signal from the antenna
302.sub.1, the sampler 304.sub.1 generates a sample data stream
305.sub.1 which is split into M sample sequences
307.sub.11-307.sub.1M by the S/P converter 306.sub.1 (i.e., a
splitter) at one times (1.times.) the chip rate. The multipath
components of each respective M sample sequence
307.sub.11-307.sub.1M are combined by a respective one of the
multipath combiners 308.sub.11-308.sub.1M which generates a
respective over-sampled stream 309.sub.11-309.sub.1M that is fed to
the over-sample combiner 310.sub.1. The over-sample combiner
310.sub.1 combines the over-sampled streams 309.sub.11-309.sub.1M
into a combined over-sampled stream 311.sub.1 which is then fed to
the antenna diversity combiner 312.
[0036] In response to receiving a signal from the antenna
302.sub.2, the sampler 304.sub.2 generates a sample data stream
305.sub.2 which is split into M sample sequences
307.sub.21-307.sub.2M by the S/P converter 306.sub.2 (i.e., a
splitter) at one times (1.times.) the chip rate. All multipath
components of each respective M sample sequence
307.sub.21-307.sub.2M are combined by a respective one of the
multipath combiners 308.sub.21-308.sub.2M which generates a
respective over-sampled stream 309.sub.21-309.sub.2M that is fed to
the over-sample combiner 310.sub.2. The over-sample combiner
310.sub.2 combines the over-sampled streams 309.sub.21-309.sub.2M
into a combined over-sampled stream 311.sub.2 which is fed to the
antenna diversity combiner 312.
[0037] In response to receiving a signal from the antenna
302.sub.N, the sampler 304.sub.N generates a sample data stream
305.sub.N which is split into M sample sequences
307.sub.N1-307.sub.NM by the S/P converter 306.sub.N (i.e., a
splitter) at one times (1.times.) the chip rate. All multipath
components of each respective M sample sequence
307.sub.N1-307.sub.NM are combined by a respective one of the
multipath combiners 308.sub.N1-308.sub.NM which generates a
respective over-sampled stream 309.sub.N1-309.sub.NM that is fed to
the over-sample combiner 310.sub.N. The over-sample combiner
310.sub.N combines the over-sampled streams 309.sub.N1-309.sub.NM
into a combined over-sampled stream 311.sub.N which is then fed to
the antenna diversity combiner 312.
[0038] The antenna diversity combiner 312 combines the combined
over-sampled streams 311.sub.1-311.sub.N into an antenna diversity
sample data stream 314 at chip rate. The antenna diversity sample
data stream 314 is input to the equalizer filter 114 and the taps
coefficients generator 116 of the 1.times. chip rate
non-over-sample processing NLMS equalizer 112.
[0039] The foregoing description is related to a despread
pilot-directed receiver. As an alternative, the receiver may be a
non-despread pilot-directed receiver. In such case, no accumulation
of the descrambled samples is performed.
[0040] FIG. 4 is a flow diagram of a process 400 including method
steps for implementing non-over-sampling processing. In step 402,
signals are received using N antennas 302.sub.1-302.sub.N, where N
is a positive integer. In step 404, a sample data stream
305.sub.1-305.sub.N is generated for each of the N antennas
302.sub.1-302.sub.N at M times the chip rate based on the received
signals, where M is a positive integer. In step 406, each sample
data stream 305.sub.1-305.sub.N is split into M sample sequences
307.sub.11-307.sub.1M, 307.sub.21-307.sub.2M, 307.sub.N1-307.sub.NM
at the chip rate. In step 408, the multipath components of each
respective sample sequence 307.sub.11-307.sub.1M,
307.sub.21-307.sub.2M, 307.sub.N1-307.sub.NM are combined to
generate a respective over-sampled stream 309.sub.11-309.sub.1M,
309.sub.21-309.sub.2M, 309.sub.N1-309.sub.NM. In step 410, the
over-sampled streams 309.sub.11-309.sub.1M, 309.sub.21-309.sub.2M,
309.sub.N1-309.sub.NM associated with the M sample sequences
307.sub.11-307.sub.1M, 307.sub.21-307.sub.2M, 307.sub.N1-307.sub.NM
are combined to generate a combined over-sampled stream
311.sub.1-311.sub.N. In step 412, the combined over-sampled streams
311.sub.1-311.sub.N of the N antennas are combined to generate an
antenna diversity sample data stream 314. In step 414, equalization
is performed on the antenna diversity sample data stream 314 with
an equalizer filter 114 at the chip rate. In step 416, filter
coefficients of the equalizer filter are adjusted by adding a
filter coefficient correction term 134 to the filter coefficients
utilized for a previous iteration. The filter coefficient
correction term 134 is generated in accordance with an error signal
131 which is generated by comparing an output from the equalizer
filter with a reference signal.
[0041] While the present invention has been described in terms of
the preferred embodiment, other variations which are within the
scope of the invention as outlined in the claims below will be
apparent to those skilled in the art.
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