U.S. patent application number 09/767953 was filed with the patent office on 2002-07-25 for orthogonal complex spreading method for multichannel and apparatus thereof.
This patent application is currently assigned to Electronics and Telecommunications Research Center. Invention is credited to Bang, Seung Chan, Han, Ki Chul, Kim, Jung Im, Kim, Tae Joong, Shim, Jae Ryong.
Application Number | 20020097779 09/767953 |
Document ID | / |
Family ID | 26633222 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020097779 |
Kind Code |
A1 |
Bang, Seung Chan ; et
al. |
July 25, 2002 |
Orthogonal complex spreading method for multichannel and apparatus
thereof
Abstract
An orthogonal complex spreading method for a multichannel and an
apparatus thereof are disclosed. The method includes the steps of
complex-summing .alpha..sub.n1W.sub.M,n1X.sub.n1 which is obtained
by multiplying an orthogonal Hadamard sequence W.sub.M,n1 by a
first data X.sub.n1 of a n-th block and .alpha.
.sub.n2W.sub.M,n2X.sub.n2 which is obtained by multiplying an
orthogonal Hadamard sequence W.sub.1,n2 by a second data X.sub.n2
of a n-th block; complex-multiplying .alpha..sub.n1W.sub.M,n1X.s-
ub.n1+j.alpha..sub.n2W.sub.M,n2X.sub.n2 which is summed in the
complex type and W.sub.M,n3+jPW.sub.M,n4 of the complex type using
a complex multiplier and outputting as an in-phase information and
quadrature phase information; and summing only in-phase information
outputted from a plurality of blocks and only quadrature phase
information outputted therefrom and spreading the same using a
spreading code.
Inventors: |
Bang, Seung Chan; (Daejeon,
KR) ; Shim, Jae Ryong; (Daejeon, KR) ; Han, Ki
Chul; (Daejeon, KR) ; Kim, Jung Im; (Daejeon,
KR) ; Kim, Tae Joong; (Daejeon, KR) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W.
SUITE 600
WASHINGTON
DC
20004
US
|
Assignee: |
Electronics and Telecommunications
Research Center
|
Family ID: |
26633222 |
Appl. No.: |
09/767953 |
Filed: |
March 27, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09767953 |
Mar 27, 2001 |
|
|
|
09162764 |
Sep 30, 1998 |
|
|
|
6222873 |
|
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Current U.S.
Class: |
375/144 ;
375/146; 375/148 |
Current CPC
Class: |
H04B 1/7097 20130101;
H04J 13/0048 20130101; H04J 13/102 20130101; H04J 2013/0037
20130101 |
Class at
Publication: |
375/144 ;
375/146; 375/148 |
International
Class: |
H04K 001/00; H04B
015/00; H04L 027/30 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 1997 |
KR |
97-65375 |
Apr 4, 1998 |
KR |
98-11923 |
Claims
What is claimed is:
1. An orthogonal complex spreading method for a multichannel,
comprising the steps of: complex-summing
.alpha..sub.n1W.sub.M,n1X.sub.n1 which is obtained by multiplying
an orthogonal Hadamard sequence W.sub.M,n1 by a first data
X.sub.n1, and gain .alpha..sub.n1, of a n-th block and
.alpha..sub.n2W.sub.M,n2X.sub.n2 which is obtained by multiplying
an orthogonal Hadamard sequence W.sub.M,n2 by a second data
X.sub.n2 and gain .alpha..sub.n2 of a n-th block;
complex-multiplying
.alpha..sub.n1W.sub.M,n1X.sub.n1+j.alpha..sub.n2W.sub.M,n2X.sub.n2
which is summed in the complex type and W.sub.M,n3+jW.sub.M,n4 of
the complex type using a complex multiplier and outputting as an
in-phase information and quadrature phase information; and summing
only in-phase information outputted from a plurality of blocks and
only quadrature phase information outputted therefrom and spreading
the same using a spreading code.
2. The method of claim 1, wherein said spreading code spreads to an
I channel and Q channel using the in-phase information and the
quadrature phase information as one spreading code.
3. The method of claim 1, wherein said spreading code is spread to
an I channel signal by multiplying an in-phase information and an
quadrature phase information by a first spreading code, multiplying
the in-phase information and the quadrature phase information by-a
second spreading code and forming I channel signal by subtracting
the quadrature phase information to which the second spreading code
is multiplied from the in-phase information to which the first
spreading code is multiplied and forming Q channel signal by
summing the quadrature phase information to which the first
spreading code is multiplied and the in-phase information to which
the second spreading code is multiplied.
4. The method of claim 1, wherein said orthogonal Hadamard sequence
uses a Walsh code.
5. The method of claim 1, wherein in said step for multiplying the
orthogonal Hadamard sequence, a sequence vector of a k-th column or
row is set to W.sub.k-1 in a M.times.M (M=4) Hadamard matrix, and
in the case of one block,
.alpha..sub.11W.sub.0X.sub.11+j.sub..alpha..sub.12W.sub.2X.- sub.12
and W.sub.0+jW.sub.1 is complex-multiplied based on
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.2 and W.sub.M,13=W.sub.0,
W.sub.M,14=W.sub.1.
6. The method of claim 5, wherein
.alpha..sub.11W.sub.0.sub.X.sub.11+j.alp- ha..sub.12W.sub.4X.sub.12
and W.sub.0+jW.sub.1, are complex-multiplied based on M=8 and
W.sub.M,12=W.sub.4.
7. The method of claim 1, wherein in said step for multiplying the
orthogonal Hadamard sequence, a sequence vector of a k-th column or
row is set to a W.sub.k-1 in a M.times.M (M is a natural number)
Hadamard matrix, and
.alpha..sub.n1W.sub.0X.sub.n1+j.alpha..sub.n2W.sub.2pX.sub.n2 and
W.sub.2n-2+jW.sub.2n-1 are complex-multiplied based on
W.sub.M,n1=W.sub.0, W.sub.M,n2=W.sub.2p (where p represents a
predetermined number in a range from 0 to (M/2)-1) and
W.sub.M,n3=W.sub.2n-2, W.sub.M,n4=W.sub.2n-1 (where n represents a
n-th block number).
8. The method of claim 1, wherein in the case of two blocks, a
resultant value which is obtaining by setting a sequence vector of
a k-th column or row to a W.sub.k-1 in a M.times.M (M=8) Hadamard
matrix and complex-multiplying
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4X- .sub.12 and
W.sub.0+jW.sub.1 based on W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.4,
W.sub.M,13=W.sub.0, W.sub.M,14 =W.sub.1, and a resultant value
which is obtained by complex-multiplying
.alpha..sub.21W.sub.0X.sub.21+j.alpha..sub.22W.sub.4X.sub.22 and
W.sub.2+jW.sub.3 based on W.sub.M,21=W.sub.0, W.sub.M,22=W.sub.4,
W.sub.M,23=W.sub.2, W.sub.M,24=W.sub.3 are summed.
9. The method of claim 8, wherein a resultant value which is
obtained by complex-multiplying
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.6X- .sub.12 and
W.sub.0+jW.sub.1 based on W.sub.M,12=W.sub.6, and
.alpha..sub.21W.sub.0X.sub.21+j.alpha..sub.22W.sub.6 X.sub.22 and
W.sub.2+jW.sub.3 are summed.
10. An orthogonal complex spreading apparatus, comprising: a
plurality of complex multiplication blocks for distributing the
data of the multichannel and complex signal
.alpha..sub.n1W.sub.M,n1X.sub.n1+j.alpha.-
.sub.n2W.sub.M,n2X.sub.n2 of which .alpha..sub.n1W.sub.M,n1X.sub.n1
which is obtained by multiplying the orthogonal Hadamard sequence
W.sub.M,n1 with the first data X.sub.n1 of the n-th block and the
gain .alpha..sub.n1 and .alpha..sub.n2W.sub.M,n2X.sub.n2 which is
obtained by multiplying the orthogonal Hadamard sequence W.sub.M,n2
with the second data X.sub.n2 of the n-th block and the gain
.alpha..sub.n2 are constituents, are complex-multiplied by
W.sub.M,n3+jW.sub.M,n4 using the complex multiplier; a summing unit
for summing only the in-phase information outputted from each block
of the plurality of the complex multiplication blocks and summing
only the quadrature phase information outputted from each block of
the plurality of the complex multiplicator blocks; and a spreading
unit for multiplying the in-phase information and the quadrature
phase information which are summed by the summing unit by the
spreading code and outputting an I channel and a Q channel.
11. The apparatus of claim 10, wherein in said spreading unit, the
in-phase information and the quadrature phase information summed by
the summing unit are multiplied by the first and second spreading
codes, the quadrature phase information to which the second
spreading code is multiplied is subtracted from the in-phase
information to which the first spreading code is multiplied for
thereby outputting an I channel, and the in-phase information to
which the second spreading code is summed by the quadrature phase
information to which the first spreading code is multiplied for
thereby outputting a Q channel.
12. The apparatus of claim 10, wherein said complex multiplication
block includes: a first multiplier for multiplying the first data
X.sub.n1 of a corresponding block by the orthogonal Hadamard
sequence W.sub.M,n1; a second multiplier for multiplying the output
signal from the first multiplier by the gain .alpha..sub.n1; a
third multiplier for multiplying the second data X.sub.n2 by the
orthogonal Hadamard sequence W.sub.M,n2; a fourth multiplier for
multiplying the output signal from the third multiplier by the gain
.alpha..sub.n2; fifth and sixth multipliers for multiplying the
output signal .alpha..sub.n1W.sub.M,n1X.sub.n1 from the second
multiplier and the output signal .alpha..sub.n2W.sub.M,n2X.sub.n2
from the fourth multiplier by the orthogonal Hadamard sequence
W.sub.M,n3; seventh and eighth multipliers for multiplying the
output signal .alpha..sub.n1W.sub.M,n1X.sub.n1 from the second
multiplier and the output signal .alpha..sub.n2W.sub.M,n2X.sub.n2
from the fourth multiplier by the orthogonal Hadamard sequence
W.sub.M,n4; a first adder for summing the output signal (ac) from
the fifth multiplier and the minus output signal (-bd) from the
eighth multiplier and outputting an in-phase information (ac-bd);
and a second adder for summing the output signal (bc) from the
sixth multiplier and the output signal (ad) from the seventh
multiplier and outputting a quadrature phase information
(bc+ad).
13. The apparatus of claim 10, wherein said orthogonal Hadamard
sequence uses a predetermined type of the orthogonal code.
14. A permutated orthogonal complex spreading method for a
multichannel, comprising the steps of: complex-summing
.alpha..sub.n1W.sub.M,n1X.sub.n1 which is obtained by multiplying a
predetermined orthogonal Hadamard sequence W.sub.M,n1 by a data
X.sub.n1 and a gain .alpha..sub.n1 and
.alpha..sub.n2W.sub.M,n2X.sub.n2 which is obtained by multiplying
the orthogonal Hadamard sequence W.sub.M,n2 of the second block by
a predetermined data X.sub.n2 and a gain .alpha..sub.n2 in the
first block during a multichannel data distribution; summing only
the in-phase information based on the output signals from a
plurality of other channels from two blocks and summing only the
quadrature phase information; and complex-multiplying 12 n = 1 K (
n1 W M , n1 X n1 + j n2 W M , n2 X n2 ) which are summed in the
complex type and W.sub.M,I+jPW.sub.M,Q which are formed of P
representing a predetermined sequence or a spreading code or a
predetermined integer using a complex multiplier and W.sub.M,I and
W.sub.M,Q which are the orthogonal Hadamard sequences, and outputs
the signal as an in-phase information and a quadrature phase
information.
15. The method of claim 14, wherein said spreading code spreads the
in-phase information and the quadrature phase information to an I
channel and Q channel using one spreading code.
16. The method of claim 14, wherein P represents a predetermined
sequence or a predetermined spreading code or a predetermined
integer.
17. The method of claim 14, wherein a sequence vector of the k-th
column or row is set to W.sub.k-l based on the M.times.M Hadamard
matrix, the conditions W.sub.M,I=W.sub.0, W.sub.M,Q=W.sub.2q+1
(where q represents a predetermined number in a range from 0 to
(M/2)-1) are obtained, and a predetermined spreading code for P is
configured so that consecutive two sequences have the identical
values.
18. The method of claim 14, wherein P is varied in accordance with
a communication environment and service type.
19. The method of claim 14, wherein said orthogonal Hadamard
sequence uses a Walsh code.
20. The method of claim 14, wherein in said step for multiplying
the orthogonal Hadamard sequences, the sequence vector of the k-th
column or row is set to W.sub.k-1, based on the M.times.M (M=4)
Hadamard matrix, and in the case that two data are transmitted, the
conditions W.sub.M.sub.M,11=W.sub.0, W.sub.M,12=W.sub.2, and
W.sub.M,I=W.sub.0, W.sub.M,Q=W.sub.1 are determined for thereby
complex-multiplying
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.2X.sub.12 and
W.sub.0+jPW.sub.1.
21. The method of claim 20, wherein said
.alpha..sub.11W.sub.0X.sub.11+j.a- lpha..sub.12W.sub.4X.sub.12 and
W.sub.0+jPW.sub.1 are complex-multiplied based on M=8 and
W.sub.M,12=W.sub.4.
22. The method of claim 14, wherein in said step for multiplying
the orthogonal Hadamard sequence, a sequence vector of the k-th
column or row is set to W.sub.k-1 based on the M.times.M Hadamard
matrix, the conditions W.sub.M,n1=W.sub.0, W.sub.M,n2=W.sub.2q+1
(where q represents a predetermined number in a range from 0 to
(M/2)-1) are obtained and the conditions W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1 (where n represent a n-th block number) for
thereby complex-multiplying .alpha..sub.n1W.sub.0X.sub.-
n1+j.alpha..sub.n2W.sub.2qX.sub.n2 and W.sub.0+jPW.sub.1.
23. The method of claim 14, wherein in said spreading unit, the
in-phase information and the quadrature phase information summed by
the summing unit are multiplied by the first and second spreading
codes, the quadrature phase information to which the second
spreading code is multiplied is subtracted from the in-phase
information to which the first spreading code is multiplied for
thereby forming an I channel, and the in-phase information to which
the second spreading code is multiplied is summed by the quadrature
phase information to which the first spreading code is multiplied
for thereby outputting a Q channel.
24. The method of claim 14, wherein said complex multiplication
block includes: a first multiplier for multiplying the first data
X.sub.n1 of a corresponding block by the gain .alpha..sub.n1; a
second multiplier for multiplying the output signal from the first
multiplier by the orthogonal Hadamard sequence W.sub.M,n1; a third
multiplier for multiplying the second data X.sub.n2 by the gain
.alpha..sub.n2; a fourth multiplier for multiplying the output
signal from the third multiplier by the orthogonal Hadamard
sequence W.sub.M,n2; fifth and sixth multipliers for multiplying
the output signal .alpha..sub.n1W.sub.M,n1X.sub.n1 from the second
multiplier and the output signal .alpha..sub.n2W.sub.M,n2X.sub.n2
from the fourth multiplier by the orthogonal Hadamard sequence
W.sub.M,I; seventh and eighth multipliers for multiplying the
output signal .alpha..sub.n1W.sub.M,n1X.sub.n1 from the second
multiplier and the output signal .alpha..sub.n2W.sub.M,n2X.sub.n2
from the fourth multiplier by the orthogonal Hadamard sequence
W.sub.M,Q; a first adder for summing the output signal (ac) from
the fifth multiplier and the minus output signal (-bd) from the
eighth multiplier and outputting an in-phase information (ac-bd);
and a second adder for summing the output signal (bc) from the
sixth multiplier and the output signal (ad) from the seventh
multiplier and outputting a quadrature phase information
(bc+ad).
25. The apparatus of claim 14, wherein a combined orthogonal
Hadamard sequence is used instead the orthogonal Hadamard sequence
in order to eliminate the phase dependency due to an interference
occurring a multipath type of a self signal and an interference
occurring by other users.
26. A permutated orthogonal complex spreading apparatus for a
multichannel, comprising: first and second Hadamard sequence
multipliers for allocating the multichannel to a predetermined
number of channels, splitting the same into two groups and
outputting .alpha..sub.n1W.sub.M,n- 1X.sub.n1 which is obtained by
multiplying the data X.sub.n1 of each channel by the gain
.alpha..sub.n2 and the orthogonal Hadamard sequence W.sub.M,n1; a
first adder for outputting 13 n = 1 K ( n1 W M , n1 X n1 ) which is
obtained by summing the output signals from the first Hadamard
sequence multiplier; a second adder for outputting 14 n = 1 K ( n2
W M , n2 X n1 ) which is obtained by summing the output signals
from the second Hadamard sequence multiplier; a complex multiplier
or receiving the output signal from the first adder and the output
signal from the second adder in the complex form of 15 n = 1 K ( n1
W M , n1 X n1 + j n2 W M , n2 X n2 ) and complex-multiplying
W.sub.M,I+jPW.sub.M,Q which consist of the orthogonal Hadamard code
W.sub.M,I, and the permutaed orthogonal Hadamard code PW.sub.M,Q
that W.sub.M,Q and a predetermined sequence P are
complex-multiplied; a spreading unit for multiplying the output
signal from the complex multiplier by the spreading code; a filter
for filtering the output signal from the spreading unit; and a
modulator for multiplying and modulating the modulation carrier
wave, summing the in-phase signal and the quadrature phase signal
and outputting a modulation signal of the real number.
27. The method of claim 26, wherein in the case of three channels,
a sequence vector of the k-th column or row is set to W.sub.k-1
based on the M.times.M (M=8) Hadamard matrix, and
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.4, W.sub.M,21=W.sub.2, and
W.sub.M,1=W.sub.0, W.sub.M,Q=W.sub.1 are determined, and the summed
value which is obtained by summing
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4X.sub.12, and
.alpha..sub.21W.sub.2X.sub.21 is complex-multiplied by
W.sub.0+jPW.sub.1.
28. The method of claim 26, wherein in the case of three channels,
a sequence vector of the k-th column or row is set to W.sub.k-1,
based on the M.times.M Hadamard matrix, and W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.2 and W.sub.M,I=W.sub.0, W.sub.M,QW.sub.1 are
determined based on M=8 , and the summed value which is obtained by
summing .alpha..sub.11W.sub.0X.sub.-
11+j.alpha..sub.12W.sub.4X.sub.12 and .alpha..sub.21W.sub.8X.sub.21
is complex-multiplied by W.sub.0+jPW.sub.1 based on M=16.
29. The method of claim 26, wherein in the case of four channels, a
sequence vector of the k-th column or row is set to W.sub.k-1,
based on the M.times.M (M=8) Hadamard matrix, and
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.4, W.sub.M,21=W.sub.2,
W.sub.M,31=W.sub.6, and W.sub.M,I=W.sub.0, W.sub.M,Q=W.sub.1 are
determined, and the summed value which is obtained by summing
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.1- 2W.sub.4X.sub.12,
.alpha..sub.21W.sub.2X.sub.21 and .alpha..sub.31W.sub.6X.sub.31 is
complex-multiplied by W.sub.0+jPW.sub.1.
30. The method of claim 26, wherein said in the case of four
channels, a sequence vector of the k-th column or row is set to
W.sub.k-1 based on the M.times.M Hadamard matrix, and
W.sub.11,11=W.sub.0, W.sub.M,12=W.sub.4, W.sub.M,31=W.sub.2,
W.sub.M,I=W, W,=W.sub.1 are determined based on M=8 and
W.sub.M,21=W.sub.8 is determined based on M=16, and the summed
value which is obtained by summing .alpha..sub.11W and is
complex-multiplied by W.sub.0+jPW.sub.1.
31. The method of claim 26, wherein in the case of five channels, a
sequence vector of the k-th column or row is set to W.sub.k-1 based
on the M.times.M (M=8) Hadamard matrix, and W.sub.M,11=W.sub.0
W.sub.M,12=W.sub.4, W.sub.M,21=W.sub.2,W F,31 =W 1 W l W, 1 and Wk,
=W,, WM, CW.sub.1 are determined, and the summed value which is
obtained by summing
.alpha..sub.11W.sub.0X.sub.11.alpha..sub.12W.sub.4X.sub.12 is
complex-multiplied by W.sub.21+jPW.sub.1.
32. The method of claim 26, wherein in the case of five channels, a
sequence vector of the k-th column or row is set to Wk1 based on
the MxM (M=8) Hadamard matrix, and W m,11=W o W.sub.M,12=W.sub.4,
W.sub.M,21=W.sub.2, M,31 W 6 t W.sub.M,22=W.sub.3, and
W.sub.14=W.sub.0, W.sub.M,Q=W.sub.1 are determined, and the summed
value which is obtained by summing
.alpha..sub.11W.sub.3X.sub.11+j.alpha..sub.12W.sub.4X.sub.12,
.alpha..sub.21W.sub.8X.sub.22+ja ?,W .sub.3X 22 and aX .sub.31W 6 X
31 is complex-multiplied by W.sub.0+jPW.sub.1.
33. The method of claim 26, wherein in the case of five channels, a
sequence vector of the k-th column or row is set to W.sub.k31 based
on the M.times.M Hadamard matrix, and W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.4 W.sub.M,31=W.sub.2, W.sub.M,22=W.sub.6, and
W.sub.M,I=W.sub.0, W.sub.M,Q=W.sub.1 are determined based on M=8
and W.sub.M,21=W.sub.8 is determined based on M=16, and the summed
value which is obtained by summing
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4X.sub.12,.alp-
ha..sub.21W.sub.8X.sub.21+j.alpha..sub.22W.sub.6X.sub.22 and
.alpha..sub.31W.sub.2X.sub.31 is complex-multiplied
W.sub.0+jPW.sub.1.
34. The method of claim 29, wherein a gain .alpha..sub.n1 and a
gain .alpha..sub.n2 are the identical gain in order to remove the
phase dependency by an interference occurring in a multipath of a
self signal and an interference occurring by other users.
35. The method of claim 29, wherein a gain .alpha..sub.n1 and a
gain .alpha..sub.n2 are the identical gain in order to remove the
phase dependency by an interference occurring in a multipath of a
self signal and an interference occurring by other users.
36. The method of claim 26, wherein a combined orthogonal Hadamard
sequence is used instead the orthogonal Hadamard sequence in order
to eliminate the phase dependency due to an interference occurring
a multipath type of a self signal and an interference occurring by
other users.
37. The method of claim 36, wherein in the case of two channel, a
sequence vector of the k-th column or row of the M.times.M (M=8)
Hadamard matrix is set to W.sub.k-1 and a sequence vector of the
m-th column or row is set to W.sub.m the first M/2 or the last M/2
is obtained from the vector W.sub.k-1 and the last M/2 or the first
M/2 is obtained from W.sub.m-1, so that the combined orthogonal
Hadamard vector is set to W.sub., and the summed value of
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4//1X.- sub.12
and W.sub.0+jPW.sub.1//4 are complex-multiplied based on
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.4//1, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1//4,
38. The method of claim 36, wherein in the case of three channels,
a sequence vector of the k-th column or row of the M.times.M (M=8)
Hadamard matrix is set to W.sub.k-1 and a sequence vector of the
m-th column or row is set to W.sub.m the first M/2 or the last M/2
is obtained from the vector W.sub.k-1, and the last M/2 or the
first M/2 is obtained from W.sub.m-1 , so that the combined
orthogonal Hadamard vector is set to W.sub.and the summed value of
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.- 12W.sub.4//1X.sub.12
and .alpha..sub.21W.sub.2X.sub.21 and W.sub.0+jPW.sub.1//4 are
complex-multiplied based on W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.4//1, W.sub.M,21=W.sub.2, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1//4.
39. The method of claim 36, wherein in the case of two channels, a
sequence vector of the k-th column or row of the M.times.M (M=8)
Hadamard vector matrix is set to W.sub.k-1, and a sequence vector
of the m-th column or row is set to W.sub.m, the first M/2 or the
last M/2 is obtained from the vector W.sub.k-1, and the last M/2 or
the first M/2 is obtained from W.sub.m-1, so that the combined
orthogonal Hadamard vector is set to W.sub.k-1//m-1, and the summed
value of .alpha..sub.11W.sub.0X.- sub.11+j.alpha.and
W.sub.0+jPW.sub.1//2 are complex-multiplied based on
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.2//1, and W.sub.M,I
40. The method of claim 36, wherein in the case of three channels,
a sequence vector of the k-th column or row of the M.times.M (M=8)
Hadamard vector matrix is set to W.sub.k-1, and a sequence vector
of the m-th column or row is set to W.sub.m, the first M/2 or the
last M/2 is obtained from the vector W.sub.k-1, and the last M/2 or
the first M/2 is obtained from W.sub.m-1, so that the combined
orthogonal Hadamard vector is set to W.sub.k-1//m-1, and the summed
value of .alpha..sub.11W.sub.0X.-
sub.11+j.alpha..sub.12W.sub.2//1X.sub.12 and
.alpha..sub.21W.sub.4X.sub.21 and W.sub.0+jPW.sub.1//2 are
complex-multiplied based on W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.2//1, W.sub.M,21=W.sub.4, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1//2.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an improved orthogonal
complex spreading method and apparatus for multiple channels. The
invention is capable of the following:
[0003] decreasing a peak power-to-average power ratio by
introducing an orthogonal complex spreading structure and spreading
input signals using a spreading code; implementing a structure
capable of spreading complex output signals using a spreading code
by adapting a permuted orthogonal complex spreading structure for a
complex-type multi-channel input signal with respect to the summed
values; and decreasing a phase dependency of an interference based
on a multipath component (when there is an one chip difference) of
a self signal, which is a problem that is not overcome by a
permuted complex spreading modulation method, nor by a combination
of an orthogonal Hadamard sequence.
[0004] 2. Description of the Prior Art
[0005] In the area of mobile communication systems, it is well
known in the art that linear and non-linear distortions affect
power amplifiers. The statistical characteristic of a peak
power-to-average power ratio has a predetermined interrelationship
for non-linear distortion.
[0006] The third order non-linear distortion, which is one of the
factors affecting the power amplifier, causes an inter-modulation
problem in an adjacent frequency channel. The inter-modulation
problem created by a high peak amplitude, which increases the
adjacent channel power (ACP), so that there is a predetermined
limit for selecting the amplifier. In particular, the Code Division
Multiple Access (CDMA) system requires a very strict condition with
respect to linearity of a power amplifier. Therefore, the
above-described condition is a very important factor.
[0007] In accordance with International Standards 97 and 98, the
FCC stipulates a condition on the adjacent channel power (ACP). In
order to satisfy the above-described condition, the bias of the
Radio Frequency (RF) power amplifier has to be limited.
[0008] According to the current IMT-2000 system standard
recommendation, a plurality of CDMA channels are recommended. In
case a plurality of channels are provided, the peak
power-to-average power ratio is considered an important factor for
increasing the efficiency of the modulation method.
[0009] The IMT-2000, which is a third generation mobile
communication system, has received a lot of attention as the next
generation communication system following the digital cellular
system, personal communication system, and etc. The IMT-2000 will
be commercially available as a wireless communication system, which
has a high capacity and performance for supporting various
multimedia services and international roaming services, etc.
[0010] Many countries have proposed utilizing IMT-2000 systems that
would require high data transmission rates for internet service or
electronic commercial activity. This is directly related to the
power efficiency of a RF amplifier.
[0011] The IMT-2000 modulation method based on CDMA technology is
classified as a pilot channel and symbol method. The pilot channel
method is directed to the CDMA ONE introduced in North America. The
pilot symbol method is directed to the NTT-DOCOMO and ARIB proposal
introduced in Japan and to the FMA2 proposal introduced in
Europe.
[0012] FIG. 1 illustrates a prior art complex spreading method
based on a CDMA ONE method.
[0013] The CDMA ONE is implemented by using a complex spreading
method. The pilot channel and the fundamental channel spread by a
Walsh code 1 are summed thereby forming in-phase information. The
supplemental channel spread by a Walsh code 2 and the control
channel spread by a Walsh code 3 are also summed thereby forming
quadrature-phase information. In addition, the in-phase and
quadrature-phase information are complex-spread by PN codes.
[0014] As shown, the signals from a fundamental channel 1A, a
supplemental channel 1B, and a control channel 1C are multiplied by
Walsh codes W.sub.4,1, W.sub.4,2 and W.sub.4,3, which is performed
by each multiplier (20A, 20B and 20C) of multiplication unit 20
through a signal-mapping unit 10. The pilot signal and the signals
multiplied by the Walsh codes are respectively multiplied by
channel gains A0, A1, A2 and A3 in channel gain multiplication unit
30.
[0015] In a summing unit 40, the pilot signal and the fundamental
channel signal are summed by a first adder 40a thereby obtaining
in-phase information. Additionally, the supplemental channel signal
and the control channel signal are summed by a second adder 40b
thereby obtaining quadrature phase information.
[0016] The in-phase and quadrature-phase information are then
multiplied by a PN1 and PN2 code by spreading unit 50. The
identical phase information multiplied by the PN2 code is then
subtracted by the in-phase information multiplied by the PN2 code
is outputted as an I channel signal. The quadrature-phase
information multiplied by the PN1 code and the in-phase information
multiplied by the PN2 code are summed and then outputted through as
a Q channel signal a delay unit 60.
[0017] FIG. 2A is a view illustrating a constellation of signals in
a phase domain before pulse shaping in a prior art CDMA ONE method
and FIG. 2B is a view illustrating a constellation of signals in a
phase domain after shaping in prior art CDMA ONE method.
[0018] In the CDMA ONE, the left and right information, namely, the
in-phase information (I channel) and the upper and lower
information, namely, the quadrature-phase information (Q channel)
pass through the actual pulse-shaping filter thereby causing a peak
power.
[0019] In view of the crest factor and the statistical distribution
of the power amplitude, the peak power is generated in a vertical
direction so that the problems such as irregular spreading of code
and crosstalk occur.
SUMMARY OF THE INVENTION
[0020] Accordingly, it is an object of the present invention to
provide an orthogonal complex spreading method and apparatus for
multiple channels that overcomes the aforementioned problems
encountered in the prior art.
[0021] The peak power-to-average power ratio is important in
IMT-2000 system since the CDMA system requires a strict condition
for linearity of a power amplifier. In particular, the IMT-2000
system provides multiple channels, which transmit signals
simultaneously, and the peak power-to-average power ratio is
related to the efficiency of the modulation method.
[0022] It is another object of the present invention to provide an
orthogonal complex spreading method and apparatus for multiple
channels, which have an excellent power efficiency compared with
the complex spreading methods introduced in the CDMA-ONE of the
United States and the W-CDMA. Additionally, the invention is
capable of resolving a power unbalance problem of an in-phase and
quadrature-phase channel as well as the complex spreading
method.
[0023] It is still another object of the present invention to
provide an orthogonal complex spreading method and apparatus for
multiple channels, which is capable of maintaining a stable low
peak power-to-average power ratio.
[0024] Additionally, in the present invention a spreading operation
is implemented as follows: multiplying predetermined channel data
among data of a multichannel by an orthogonal Hadamard sequence and
a gain; multiplying data of another channel by an orthogonal
Hadamard sequence and a gain; summing the information of the two
channels in complex type; multiplying the summed information of the
complex type by the orthogonal Hadamard sequence of the orthogonal
type; obtaining a complex type; summing a plurality of channel
information of the complex type in the above-described manner; and
multiplying the information of the complex type of the multichannel
by a spreading code sequence.
[0025] Furthermore, it is an object of the present invention to
decrease the probability that the power drops to zero by doing the
following: preventing the FIR filter input state from exceeding
90.degree. in an earlier sample state; increasing the power
efficiency and decreasing the consumption of bias power for a
back-off of the power amplifier; and saving the power of a
battery.
[0026] It is still another object of the present invention to
provide an orthogonal complex spreading method and apparatus for a
multichannel, which is capable of implementing a Permuted
Orthogonal Complex QPSK (POCQPSK) which is another modulation
method that has a power efficiency similar with the Orthogonal
Complex QPSK (OCQPSK).
[0027] In order to achieve the above objects, there is an
orthogonal complex spreading method that is provided for a
multichannel which includes the following steps:
[0028] complex-summing .alpha..sub.n1W.sub.M,n1X.sub.n1 which is
obtained by multiplying an orthogonal Hadamard sequence W.sub.M,n1
by a first set of data of X.sub.n1 of a n-th block, and a
.alpha..sub.n2W.sub.M,n2X.sub.- n2, which is obtained by
multiplying an orthogonal Hadamard sequence W.sub.M,n2 by a second
set of data of X.sub.n2 of a n-th block; complex-multiplying
.alpha..sub.n1W.sub.M,n1X.sub.n1+j.alpha..sub.n2W.sub-
.M,n2X.sub.n2, which is summed in the complex type, and
W.sub.M,n3+jW.sub.M,n4 of the complex type using a complex
multiplier and outputting in-phase and quadrature-phase
information; summing only in-phase information outputted from a
plurality of blocks and only quadrature-phase information outputted
therefrom; and spreading the same using a spreading code.
[0029] In order to achieve the above objects, there is provided an
orthogonal complex spreading apparatus according to a one
embodiment of the present invention which includes the following: a
plurality of complex multiplication blocks for distributing the
data of the multichannel and complex-multiplying
.alpha..sub.n1W.sub.M,n1X.sub.n1+j.a-
lpha..sub.n2W.sub.n2X.sub.M,n1 in which
.alpha..sub.n1W.sub.M,n1X.sub.n1 is obtained by multiplying the
orthogonal Hadamard sequence W.sub.M,n1 with the first set of data
of X.sub.n1, of the n-th block and the gain .alpha..sub.n1 and
.alpha..sub.n2W.sub.M,n2X.sub.n2 which is obtained by multiplying
the orthogonal Hadamard sequence W.sub.M,n2 with the second set of
data of X.sub.n2 of the n-th block and the gain .alpha..sub.n2 and
W.sub.M,n3+W.sub.M,n4 using the complex multiplier; a summing unit
for summing only the in-phase information outputted from each block
of the plurality of the complex multiplication blocks and summing
only the quadrature-phase information; and a spreading unit for
multiplying the in-phase and quadrature-phase information summed by
the summing unit with the spreading code and outputting an I
channel and a Q channel.
[0030] In order to achieve the above objects, there is provided an
orthogonal complex spreading apparatus according to another
embodiment of the present invention, which includes the following:
first and second Hadamard sequence multipliers for allocating the
multichannel to a predetermined number of channels, splitting the
same into two groups and outputting
.alpha..sub.n1W.sub.M,n1X.sub.n1, which is obtained by multiplying
the data X.sub.n1 of each channel by the gain .alpha..sub.n1 and
the orthogonal Hadamard sequence W.sub.M,n1; a first adder for
outputting
[0031] 1 n = 1 K ( n1 W M , n1 X n1 ) ,
[0032] which is obtained by summing the output signals from the
first Hadamard sequence multiplier; a second adder for
outputting
[0033] 2 n = 1 K ( n2 W M , n2 X n2 ) ,
[0034] which is obtained by summing the output signals from the
second Hadamard sequence multiplier; a complex multiplier for
receiving the output signal from the first and second adder in the
complex form of
[0035] 3 n = 1 K ( n1 W M , n1 X n1 + j n2 W M , n2 X n2 )
[0036] and complex-multiplying W.sub.M,I+jPW.sub.M,Q where n=1
consists of the orthogonal Hadamard code W.sub.M,I and the permuted
orthogonal Hadamard code PW.sub.M,Q where W.sub.M,Q and a
predetermined sequence P are complex-multiplied; a spreading unit
for multiplying the output signal from the complex multiplier by
the spreading code; a filter for filtering the output signal from
the spreading unit; and a modulator for multiplying and modulating
the modulation carrier wave, summing the in-phase and
quadrature-phase signal and outputting a modulation signal of the
real number.
[0037] Additional advantages, objects and other features of the
invention will be set forth in the description which follows and
will become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from practice of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The present invention will become more fully understood from
the detailed description given below and the accompanying drawings,
which are given by way of illustration only, and thus are not
limitative of the present invention, and wherein:
[0039] FIG. 1 is a block diagram illustrating a prior art
multichannel complex spreading method of a CDMA ONE method;
[0040] FIG. 2A is a view illustrating a constellation of signals in
a phase domain before pulse shaping in a prior art CDMA ONE
method;
[0041] FIG. 2B is a view illustrating a constellation of signals in
a phase domain after pulse shaping in a prior art CDMA ONE
method;
[0042] FIG. 4 is a block diagram illustrating a multi-channel
orthogonal complex spreading apparatus in accordance with one
embodiment of the present invention;
[0043] FIG. 5A is a circuit diagram illustrating the complex
multiplier of FIG. 4;
[0044] FIG. 5B is a circuit diagram illustrating the summing unit
and spreading unit of FIG. 4;
[0045] FIG. 5C is a circuit diagram illustrating another embodiment
of the spreading unit of FIG. 4;
[0046] FIG. 5D is a circuit diagram illustrating the filter and
modulator of FIG. 4;
[0047] FIG. 6A is a view illustrating a constellation of signals in
a phase domain before pulse shaping in an OCQPSK according to the
present invention;
[0048] FIG. 6B is a view illustrating a constellation of signals in
a phase domain after pulse shaping in an OCQPSK in accordance with
the present invention;
[0049] FIG. 7 is a view illustrating a statistical distribution
characteristic of power peak occurrences with respect to an average
power between the prior art and the present invention;
[0050] FIG. 8 illustrates an example of an orthogonal Hadamard
sequence in accordance with the present invention;
[0051] FIG. 9 is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus in accordance with
another embodiment of the present invention;
[0052] FIG. 10 is a circuit diagram illustrating the complex
multiplier of FIG. 8;
[0053] FIG. 11 is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus with two input
channels in accordance with the present invention;
[0054] FIG. 12 is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus with three input
channels in accordance with the present invention;
[0055] FIG. 13A is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus for a QPSK having a
high transmission rate with the present invention;
[0056] FIG. 13B is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus with four input
channels in accordance with the present invention;
[0057] FIG. 14A is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus for a multimedia
service in accordance with the present invention;
[0058] FIG. 14B is a circuit diagram illustrating a multichannel
permuted orthogonal complex spreading apparatus with five input
channels in accordance with the present invention;
[0059] FIG. 15A is a phase trajectory view of an OCQPSK according
to the present invention;
[0060] FIG. 15B is a phase trajectory view of a POCQPSK according
to the present invention; and
[0061] FIG. 15C is a phase trajectory view of a prior art complex
spreading method.
DETAILED DESCRIPTION OF THE INVENTION
[0062] The complex summing unit and complex multiplier, according
to the present invention, will be explained with reference to the
accompanying drawings. In the present invention, assuming that two
complex number (a+jb) and (c+jd) are used, where a, b, c and d
represent predetermined real numbers, a complex summing unit
outputs (a+c)+j(b+d) and a complex multiplier outputs
((a.times.c)-(b.times.d))+j((b.times.c)+(a.times.d)). The following
items are defined for the invention: a spreading code sequence is
defined as SC; information data is defined as X.sub.n1 and
X.sub.n2; a gain constant is defined as .alpha..sub.n1 and
.alpha..sub.n2; and an orthogonal Hadamard sequence is defined as
W.sub.M,n, W.sub.M,n2, W.sub.M,n3, W.sub.M,n4, W.sub.M,I,
W.sub.M,Q, where M represents a M.times.M Hadamard matrix and n1,
n2, n3 and n4 represent an index of predetermined vectors of the
Hadamard matrix. For example, n3 represents a Hadamard vector,
wherein W.sub.M,n3 is a third vector value described in n-th block
100n shown in FIG. 4.
[0063] The data X.sub.n1, X.sub.n2, W.sub.M,n1, W.sub.M,n2,
W.sub.M,n3, W.sub.M,n4, W.sub.M,I, and W.sub.M,Q and spreading
sequence SC are combined data consisting of +1 or --1.
.alpha..sub.n1 and .alpha..sub.n2 are real numbers.
[0064] FIG. 4 is a block diagram illustrating a multichannel
orthogonal complex spreading apparatus, in accordance with one
embodiment of the present invention.
[0065] As shown therein, there is provided a plurality of complex
multipliers 100 through 100n. In a complex multiplier 100n, data
X.sub.n1 of a predetermined channel is multiplied by a gain
.alpha..sub.n1 and an orthogonal Hadamard sequence W.sub.M,n1 and
data X.sub.n2 of another channel is multiplied by a gain
.alpha..sub.n2 and an orthogonal Hadamard sequence W.sub.M,n2. The
data from both channels are complex-summed and then the complex
orthogonal Hadamard sequence W.sub.M,n3+jW.sub.M,n4 is multiplied
by the complex-summed data .alpha..sub.n1W.sub.M,n1X.sub.n1+j.-
alpha..sub.n2W.sub.M,n2X.sub.n2 and the data of the other
complex-multipliers are obtained in the same manner as described
above. The summing unit 200 sums the output signals from complex
multipliers 100 through 100n. The spreading unit 300 multiplies the
output signal from the summing unit 200 with a predetermined SC,
thereby spreading the signal. A pulse-shaping filter 400 filters
the data spread by the spreading unit 300. A modulation wave
multiplier 500 multiplies the output signal from the filter 400
with a modulation carrier wave e.sup.2.pi.fct.
[0066] As shown in FIG. 4, the first complex multiplier 100
complex-sums .alpha..sub.11W.sub.M,11X.sub.11, obtained by
multiplying the orthogonal Hadamard sequence W.sub.M,11 with the
data X.sub.11 of one channel and the gain .alpha..sub.11, and
.alpha..sub.12W.sub.M,12X.sub.12, obtained by multiplying the
orthogonal Hadamard sequence W.sub.M,12 with the data X.sub.12 of
another channel and the gain .alpha..sub.12. The
.alpha..sub.11W.sub.M,11X.sub.11+j.alpha..sub.12W.sub.M,12X.sub.12
is then multiplied by the complex-type orthogonal sequence
W.sub.M,13X.sub.11+jW.sub.M,14 at the complex multiplier 111.
[0067] In addition, the n-th complex multiplier 100n complex-sums
.alpha..sub.n1W.sub.M,n1X.sub.n1, obtained by multiplying the
orthogonal Hadamard sequence W.sub.M,n1 with the data X.sub.n1 of
another channel and the gain .alpha..sub.n1, and
.alpha..sub.n2W.sub.M,n2X.sub.n2, obtained by multiplying the
orthogonal Hadamard sequence W.sub.M,n2 with the data X.sub.n2 of
another channel and the gain .alpha..sub.n2. The
.alpha..sub.n1W.sub.M,n1X.sub.n1+j.alpha..sub.n2W.sub.M,n2X.sub.n2
is complex-multiplied by the complex-type orthogonal sequence
W.sub.M,n3X.sub.11+jW.sub.M,n4 at the complex multiplier 100n.
[0068] The complex multiplication data outputted from the n-number
of the complex multipliers are summed at the summing unit 200, and
the spreading code SC is multiplied and spread by using the
spreading unit 300. The spread data is filtered at the
pulse-shaping filter 600 and then multiplied by the modulation
carried e.sup.j2.pi.fct at the multiplier 700. The modulated signal
is then processed by the function Re{*} 70 to thereby output the
real data s(t) 80 through the antenna. Here, Re{*} 70 represents a
function through which a predetermined complex number is processed
as a real value.
[0069] The above-described function will be explained as
follows:
[0070] 4 ( n = 1 K ( ( n1 W M , n1 X n1 + j n2 W M , n2 X n2 )
.times. ( W M , n3 + j W M , , n4 ) ) ) .times. SC
[0071] K represents a predetermined integer greater than or equal
to 1; and n represents an integer greater than or equal to 1 and
less than K and is identical with the index of each complex
multiplier.
[0072] In FIG. 5A, the complex multiplier includes the following: a
first multiplier 101; a second multiplier 102; a third multiplier
103; a fourth multiplier 104; fifth and sixth multipliers 105 and
106; seventh and eighth multipliers 107 and 108; a first adder 109;
and a second adder 110.
[0073] The first and second multipliers 101 and 102 multiply the
data X.sub.11, by the orthogonal Hadamard sequence W.sub.M,11 and
the gain .alpha..sub.11 thereby obtaining
.alpha..sub.11W.sub.M,11X.sub.11(=a). In addition, the third and
fourth multipliers 103 and 104 multiply the orthogonal Hadamard
sequence W.sub.M,12 and the gain .alpha..sub.12 thereby obtaining
.alpha..sub.12W.sub.M,12X.sub.12(=b). The fifth and sixth
multipliers 105 and 106 multiply
.alpha..sub.11W.sub.M,11X.sub.11(=- a) and
.alpha..sub.12W.sub.M,12X.sub.12(=b) by the orthogonal Hadamard
sequence W.sub.M,13(=c), respectively, for thereby obtaining
.alpha..sub.11W.sub.M,11X.sub.11W.sub.M,13(=ac) and
.alpha..sub.12W.sub.M,12X.sub.12W.sub.M,13(=bc). Additionally, the
fifth and sixth multipliers 105 and 106 multiply
.alpha..sub.11W.sub.M,11X.sub.- 11(=a) and
.alpha..sub.12W.sub.M,12X.sub.12(=b) by the orthogonal Hadamard
sequence W.sub.M,14(=d) thereby obtaining
.alpha..sub.11W.sub.M,11X.sub.1- 1W.sub.M,14(=ad) and
.alpha..sub.12W.sub.M,12X.sub.12W.sub.M,14(=bd). Thus,
.alpha..sub.12W.sub.M,12X.sub.12W.sub.M,14 is subtracted from
.alpha..sub.11W.sub.M,11X.sub.11W.sub.M,13. The second adder 110
then computes
(.alpha..sub.11W.sub.M,11X.sub.11W.sub.M,14)+(.alpha..sub.12W.su-
b.M,12X.sub.12W.sub.M,13) (ad+bc). Specifically,
.alpha..sub.11W.sub.M,11X- .sub.11W.sub.M,14(=ad) is added with
.alpha..sub.12W.sub.M,12X.sub.12W.sub- .M,13(=bc).
[0074] Referring back to FIG. 4, the first complex multiplier 100
is configured identically with the n-th complex multiplier 100n.
The expression "(a+jb)(c+jd)=ac-bd+j(bc+ad)" is obtained assuming
that .alpha..sub.11W.sub.M,11X.sub.11 is "a",
.alpha..sub.12W.sub.M,12X.sub.12 is "b", the orthogonal Hadamard
sequence W.sub.M,13 is "c", and the orthogonal Hadamard sequence
W.sub.M,14 is "d". Therefore, the signal outputted from the first
complex multiplier 100 becomes the in-phase information "ac-bd" and
the quadrature-phase information "bc+ad".
[0075] In addition, FIG. 5B is a circuit diagram illustrating the
summing and spreading unit of FIG. 4 and FIG. 5C is a circuit
diagram illustrating another embodiment of the spreading unit of
FIG. 4.
[0076] As shown therein, the summing unit 200 includes a first
summing unit 210 for summing the in-phase information
A.sub.1(=(ac-bd)) outputted from a plurality of complex multipliers
and a second summing unit 220 for summing the quadrature-phase
information B.sub.1(=(bc+ad)) outputted from the complex
multipliers.
[0077] The spreading unit 300 includes first and second multipliers
301 and 302 for multiplying the output signals from the first adder
210 and the second adder 220 of the summing unit 200 by the SC. In
other words, the in-phase and quadrature-phase signals are spread
by the same SC.
[0078] In FIG. 5C, the spreading unit 300 includes the following:
first and second multipliers 310 and 320; third and fourth
multipliers 330 and 340; a first adder 350; and a second adder
360.
[0079] In the summing unit 200, the in-phase and quadrature-phase
information of the n-number of the complex multipliers are summed
by the first and second adders 210 and 220. In the spreading unit
300, the in-phase value (g) and the quadrature phase value (h) from
the summing unit 200 are multiplied by the first spreading code SC1
(1) by the first and second multipliers 310 and 320 thereby
obtaining gl and hl, in addition, the in-phase value (g) and the
quadrature phase value (h) from the summing unit 200 are multiplied
by the second spreading code SC2(m) by the third and fourth
multipliers 330 and 340 thereby obtaining gm and hm. The first
adder 350 computes gl-hm, in which hm is subtracted from gl, and
the second adder 360 computes hl+gm, in which hl is added by
gm.
[0080] In FIG. 5D, the filter 400 includes first and second pulse
shaping filters 410 and 420 for filtering the I channel signal,
which is the in-phase information shown in FIG. 5B and 5C, and the
Q channel signal, which is the quadrature phase information signal.
The modulation unit 500 includes the following: first and second
multipliers 510 and 520 for multiplying the output signals from the
first and second pulse shaping filters 410 and 420 by
cos(2.pi.f.sub.ct) and sin(2.pi.f.sub.ct); and an adder 530 for
summing the output signals from the first and second multipliers
510 and 520 and outputting a modulation data S(t).
[0081] In the present invention, the orthogonal Hadamard sequences
may be replaced by a Walsh code or other orthogonal code.
[0082] FIG. 8 illustrates a 8.times.8 Hadamard matrix as an example
of the Hadamard or Walsh code. The sequence vector of a k-th column
or row is set to W.sub.k-1. In this case, if k is 1, W.sub.k-1
represents W.sub.0 of the column or row and if k is 5, W.sub.k-1
represents W.sub.4 of the column or row.
[0083] In order to enhance the efficiency of the present invention,
the orthogonal Hadamard sequence by which multiplies each channel
data is multiplied, is determined as follows. In the M.times.M
Hadamard matrix, the sequence vector of the k-th column or row is
set to W.sub.k-1. It can be set that
W.sub.M,n1=W.sub.0,W.sub.M,n2=W.sub.2p (where p represents a
predetermined number of (M/2)-1), W.sub.M,n3=W.sub.2n-2,
W.sub.M,n4=W.sub.2n-1 (where n represents the number of n-th
blocks) so that
.alpha..sub.n1W.sub.0X.sub.n1+j.alpha..sub.n2W.sub.2pX.sub.n2 is
complex-multiplied by W.sub.2n-2+jW.sub.2n-1.
[0084] In FIG. 4, if only the first complex multipliers are used,
then, only two channels are complex-multiplied, so that it can be
determined that W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.2, or
W.sub.M,12=W.sub.4, W.sub.M,13=W.sub.0, and W.sub.M,14=W.sub.1, so
that .alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.2X.sub.12
or .alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4X.sub.12 is
complex-multiplied by W.sub.0+jW.sub.1.
[0085] If the two complex multipliers are used in FIG. 4 it can be
determined that W.sub.M,21=W.sub.0W.sub.M,22=W.sub.4,
W.sub.M,23=W.sub.2 and W.sub.M,24=W.sub.3, so that
.alpha..sub.21W.sub.0X.sub.21+j.alpha..su- b.22W.sub.4X.sub.22 is
complex-multiplied by W.sub.2+jW.sub.3.
[0086] Additionally, if spreading is implemented by using the SC,
as shown in FIG. 5, one spreading code may be used. However, two
spreading codes SC1 and SC2 may also be used, as shown in FIG.
5C.
[0087] In order to achieve the objects of the present invention,
the combined orthogonal Hadamard sequence may be used instead of
the orthogonal Hadamard sequence thereby removing phase dependency
based on the interference generated in the multiple paths of
self-signal and the interference other users.
[0088] If the sequence vector of the k-th column or row is set to
W.sub.k-1 in the M.times.M (M=8) Hadamard matrix, and the sequence
vector of the m-th column or row is set to W.sub.m, the combined
orthogonal Hadamard vector W.sub.k-1/m-1 is constructed by taking
the first M/2 or the last M/2 from the vector W.sub.k-1, and the
last M/2 or the first M/2 from W.sub.m-1. In the case of two
channels, for example, it is possible to determine
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.4/1, W.sub.M,1=W.sub.0,
W.sub.M,Q=W.sub.1/4, so that
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.1- 2W.sub.4/1X.sub.12 is
complex-multiplied by W.sub.0+jPW.sub.1/4.
[0089] In the case of three channels, the summed value of
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.4/1X.sub.12 and
.alpha..sub.21W.sub.2X.sub.21 are complex-multiplied by
W.sub.0+jPW.sub.1/4 based on W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.4/1, W.sub.M,21=W.sub.2, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1/4.
[0090] In addition, in the case of two channels, to the summed
value of
.alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.2/1X.sub.12 are
complex-multiplied by W.sub.0+jPW.sub.1/2 based on
W.sub.M,11=W.sub.0, W.sub.M,12=W.sub.2/1, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1/2.
[0091] In addition, in the case of three channels, the summed value
of .alpha..sub.11W.sub.0X.sub.11+j.alpha..sub.12W.sub.2/1X.sub.12
and .alpha..sub.21W.sub.4X.sub.21 are complex-multiplied by
W.sub.0+jPW.sub.1/2 based on W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.2/1, W.sub.M,21=W.sub.4, and W.sub.M,I=W.sub.0,
W.sub.M,Q=W.sub.1/2.
[0092] Therefore, the cases of two and three channels have been
explained. The two and three channels may be selectively used in
accordance with the difference of the impulse response
characteristic of the pulse shaping band pass filter.
[0093] FIG. 6A is a view illustrating a constellation of signals in
a phase domain before pulse shaping in the OCQPSK in accordance
with the present invention. FIG. 6B is a view of a constellation of
signals in a phase domain after pulse shaping in an OCQPSK of FIG.
6A. FIG. 7 is a view illustrating a statistical distribution
characteristic of power peak occurrences with respect to an average
power between the prior art CDMA ONE and the present invention. The
embodiment of FIG. 6A is similar to FIG. 2A. However, there is a
difference in the signals after the pulse shaping. In FIG. 6B, the
range of the upper and lower information (Q channel) and the left
and right information (I channel) are saturated to their respective
limits. This causes the difference of the statistical distribution
of the peak power-to-average power.
[0094] FIG. 7 illustrates the peak power-to-average power ratio
based on the result of the actual simulation between the present
invention and the prior art. In order to provide identical
conditions, the power level of the control or signal channel is set
to the same the same power level of the communication channel
(Fundamental channel, Supplemental channel; or In-phase channel,
the Quadrature channel). Additionally, the power level of the pilot
channel is set lower than the power level of the communication
channel by 4dB. In the above-described condition, the statistical
distributions of the peak power-to-average power are compared.
[0095] In case of OCQPSK, in accordance with the present invention,
the comparison is implemented by using the first complex multiplier
100 and the n-th complex multiplier 100n shown in FIG. 4. The first
block 100 is implemented based on W.sub.M,11=W.sub.0,
W.sub.M,12=W.sub.4, W.sub.M,13=W.sub.0, and W.sub.M,14=W.sub.1, and
the n-th block 100n is implemented based on W.sub.M,n1=W.sub.0,
W.sub.M,n2=W.sub.4, W.sub.M,n3=W.sub.2, and W.sub.M,n4=W.sub.3. In
addition, the SCI is used as spreading code, and the SC2 is not
used.
[0096] In the case of OCQPSK, the probability that the
instantaneous power exceeds the average power value (0 dB) by 4 dB
is 0.03%, and in the case of CDMA ONE, it is 0.9%. Therefore, the
present invention has a very excellent characteristic with respect
to the power efficiency and as a new modulation method, it reduces
the crosstalk interference problem.
[0097] FIG. 9 illustrates a POCQPSK in accordance with the present
invention. As shown therein, one or a plurality of channels are
combined and complex-multiplied by the permuted orthogonal Hadamard
code and then are spread by the spreading code.
[0098] In FIG. 9, the following items are provided: first and
second Hadamard sequence multipliers 600 and 700 for respectively
having a predetermined number of channels allocated and outputting
.alpha..sub.n1W.sub.M,n1X.sub.n1 which is obtained by multiplying
the data X.sub.n1 of each channel by the gain .alpha..sub.n1 and
the orthogonal Hadamard sequence W.sub.M,n1;
.alpha..sub.n2W.sub.M,n2X.sub.n2- , which is obtained by
multiplying the data X.sub.n2 of the gain .alpha..sub.n2 and the
orthogonal Hadamard sequence W.sub.M,n2; a first adder 810 for
outputting
[0099] 5 n = 1 K ( n1 W M , n1 X n1 ) ,
[0100] which is obtained by summing the output signals from the
first Hadamard sequence multiplier 600; a second adder 820 for
outputting
[0101] 6 n = 1 K ( n2 W M , n2 X n2 ) ,
[0102] which is obtained by summing the output signals from the
second Hadamard sequence multiplier 700; a complex multiplier 900
for receiving the output signal from the first adder 810 and the
output signal from the second adder 820 in the complex form of
[0103] 7 n = 1 K ( n1 W M , n1 X n1 + j n2 W M , n2 X n2 )
[0104] and complex multiplying the received signal by
W.sub.M,I+jPW.sub.M,Q, which consist of the orthogonal Hadamard
code W.sub.M,I, and the permuted orthogonal Hadamard code
PW.sub.M,Q, wherein W.sub.M,Q and a predetermined sequence P are
multiplied; a spreading unit 300 for multiplying the output signal
from the complex multiplier 900 by a spreading code; a filter 400
for filtering the output signal from the spreading unit 300; and a
modulator 500 for modulating the output signal from the filter 400
by multiplying the modulation carrier wave, summing the in-phase
signal and the quadrature phase signal and outputting a real part
of the modulated signal.
[0105] Additionally, in FIG. 9 the construction of the spreading
unit 300, the filter 400 and the modulator 500 is the same as the
embodiment of FIG. 4. However, in FIG. 9, the multiplication of the
complex orthogonal Hadamard sequence is separated from the complex
multiplier 100 through 100n and implemented in the rear portion of
the summing unit. The multiplication of each channel by the complex
orthogonal Hadamard sequence is not implemented, and the summed
signals of two groups are multiplied by the complex type orthogonal
Hadamard sequence.
[0106] In the first orthogonal Hadamard sequence multiplier 600
.alpha..sub.11W.sub.M,11X.sub.11, is obtained through multiplier
610, 611, 620, 621, 630, 631, 640 and 641 by multiplying first data
X.sub.11 of the first group by the orthogonal Hadamard sequence
W.sub.M,11 and the gain .alpha..sub.11 . Respectively,
.alpha..sub.21W.sub.M,21X.sub.21 is obtained by multiplying the
second data X.sub.21 of the first group by orthogonal Hadamard
sequence W.sub.M,21 and the gain .alpha..sub.21. Additionally
.alpha..sub.n1W.sub.M,n1X.sub.n1 is obtained by multiplying the
n-th data X.sub.n1 of the first group by orthogonal Hadamard
sequence WM,nl and the gain .alpha..sub.n1.
[0107] The first adder 810 sums .alpha..sub.n1W.sub.M,n1X.sub.n1 of
each channel to output
[0108] 8 n = 1 K ( 11 W M , 11 X 11 ) .
[0109] In the second orthogonal Hadamard sequence multiplier 700,
.alpha..sub.12W.sub.M,12X.sub.12 is obtained through multiplier
720, 721, 730, 731, 740 and 741 by multiplying the first data
X.sub.12 of the second group by the orthogonal Hadamard sequence
W.sub.M,12 and the gain .alpha..sub.12 Respectively,
.alpha..sub.22W.sub.M,22X.sub.22 is obtained by multiplying the the
second data X.sub.22 of the second group by the Hadamard sequence
W.sub.M,22 and the gain .alpha..sub.22. Additionally,
.alpha..sub.n2W.sub.M,n2X.sub.n2 is obtained by multiplying the
n-th data X.sub.n2 of the second group by the orthogonal sequence
W.sub.M,n2 and the gain .alpha..sub.n2.
[0110] The second adder 820 sums .alpha..sub.n2W.sub.M,n2X.sub.n2
of each channel to output
[0111] 9 n = 1 K ( n2 W M , n2 X n2 ) .
[0112] The signal outputted from the first adder 810 forms an
in-phase data and the signal outputted from the second adder 820
forms quadrature phase data. In addition, the complex multiplier
900 receives the output signals in the complex form from the first
and second adder 810 and 820 and multiplies the complex output
signals
[0113] 10 n = 1 K ( n1 W M , n1 X n1 + j n2 W M , n2 X n2 )
[0114] from the first and second adders 810 and 820 by a complex
signal of W.sub.M,I+jPW.sub.M,Q that is comprised of an orthogonal
Hadamard code W.sub.M,I and PW.sub.M,Q, which results from the
multiplication of the orthogonal Hadamard code W.sub.M,Q by the
sequence P. P is a predetermined sequence, spreading code or
integer configured so that two consecutive sequences have identical
values. Accordingly, the complex output signals from the first and
second adders 810 and 820 are complex-multiplied by the complex
signals of W.sub.M,I+jPW.sub.M,Q by the complex multiplier 900.
[0115] The spreading unit 300 multiplies the output signal from the
complex multiplier 900 by the spreading code SCI and spreads the
same. Thus, the spread signals are then filtered by the pulse
shaping filters 410 and 420. The modulation carrier waves of
cos(2.pi.f.sub.ct) and sin(2.pi.f.sub.ct) are multiplied by the
modulation multipliers 510 and 520 thereby outputting s(t). In the
following equation is obtained.
[0116] 11 ( n = 1 K ( n1 W M , n1 X n1 + j n2 W M , n2 X n2 ) )
.times. ( W M , I + jPW M , Q ) .times. SC
[0117] where K represents an integer greater than or equal to
1.
[0118] FIG. 10 illustrates an embodiment where two channel data are
complex-multiplied. Channel data X.sub.11, is allocated to the
first orthogonal Hadamard sequence multiplier 600 and another
channel data X.sub.12 is allocated to the second orthogonal
Hadamard sequence multiplier 700.
[0119] As shown, the orthogonal Hadamard sequence multiplier
includes the following:
[0120] a first multiplier 610; a second multiplier 611; a third
multiplier 710; and a fourth multiplier 711.
[0121] The complex multiplier 900 includes the following: fifth and
sixth multipliers 901 and 902; seventh and eighth multipliers 903
and 904 multiplier 711 by the permutated; a first adder 905; and a
second adder 906.
[0122] Therefore, the first and second multipliers 610 and 611
multiply the data X.sub.11 by the orthogonal Hadamard sequence
W.sub.M,11 and the gain all thereby outputting
.alpha..sub.11W.sub.M,11X.sub.11(=a). In addition, the third and
fourth multipliers 710 and 711 multiply the data X.sub.12 by the
orthogonal Hadamard sequence W.sub.M,12 and the gain .alpha..sub.12
thereby outputting .alpha..sub.12W.sub.M,12X.sub.12(=b). The fifth
and sixth multipliers 901 and 902 multiply
.alpha..sub.11W.sub.M,11X.sub.11(=a) and
.alpha..sub.12W.sub.M,12X.sub.12- (=b) by the orthogonal Hadamard
sequence W.sub.M,I(=c) thereby generating
.alpha..sub.11W.sub.M,11X.sub.11W.sub.M,I(=ac) and
.alpha..sub.12W.sub.M,12X.sub.12W.sub.M,I(=bc). The seventh and
eighth multipliers 903 and 904 multiply
.alpha..sub.11W.sub.M,11X.sub.11(=a) and
.alpha..sub.12W.sub.M,12X.sub.12(=b) by the permuted orthogonal
Hadamard sequence PW.sub.M,Q thereby generating
.alpha..sub.11W.sub.M,11X.sub.11PW- .sub.M,Q(=ad) and
.alpha..sub.12W.sub.M,12(=bd).
[0123] The first adder 905 outputs
(.alpha..sub.11W.sub.M,11X.sub.11W.sub.-
M,I)-(.alpha..sub.12W.sub.M,12X.sub.12PW.sub.M,Q) (=ac-bd). That
is, .alpha..sub.12W.sub.M,12X.sub.12PW.sub.M,Q(bd) is subtracted
from .alpha..sub.11W.sub.M,11X.sub.11W.sub.M,I(=ac). The second
adder 906 generates
(.alpha..sub.11W.sub.M,11X.sub.11PW.sub.M,Q)+(.alpha..sub.12W.s-
ub.M,12X.sub.12W.sub.M,I)(=ad+bc). That is,
(.alpha..sub.11W.sub.M,11X.sub- .11PW.sub.M,Q)(=ad) is summed by
(.alpha..sub.12W.sub.M,12X.sub.12W.sub.M,- I) (bc).
[0124] FIG. 10 illustrates the complex multiplier 900 shown in FIG.
9. For example, .alpha..sub.11W.sub.M,11X.sub.11 is "a",
.alpha..sub.12W.sub.M,1- 2X.sub.12 is "b", the orthogonal Hadamard
sequence W.sub.M,I is "c", and the permuted orthogonal Hadamard
sequence PW.sub.M,Q is "d". Since (a+jb)(c+jd)=ac-bd+j(bc+ad), the
signal from the complex multiplier 900 consists of the in-phase
information ac-bd and the quadrature phase information bc+ad.
[0125] The in-phase and quadrature phase information is spread by
the spreading unit 300 based on the spreading code (for example, PN
code). In addition, the I channel signal, which is the in-phase
information, and the Q channel signal, which is the quadrature
phase information signal, are filtered by the first and second
pulse shaping filters 410 and 420. The first and second multipliers
510 and 520 multiply the output signals from the first and second
pulse shaping filters 410 and 420 by cos(2.pi.f.sub.ct) and
sin(2.pi.f.sub.ct). The output signals from the multipliers 510 and
520 are summed by the adder 530 which outputs S(t).
[0126] The embodiment as shown in FIG. 9 is identical to FIG. 4
instead of orthogonal Hadamard sequence, Walsh code or other
orthogonal code may be used. In addition, in the orthogonal
Hadamard sequence of each channel, the sequence vector of the k-th
column or row is set to W.sub.k-l in the M.times.M Hadamard matrix.
Preferably, .alpha..sub.n1W.sub.0X.sub.n1+j.al-
pha..sub.n2W.sub.2pX.sub.n2 and W.sub.0+jPW.sub.1 are
complex-multiplied based on W.sub.M,n1=W.sub.0, W.sub.M,n2=W.sub.2p
(where p represents a predetermined number in a range from 0 to
(M/2)-1, and W.sub.M,1=W.sub.0, W.sub.M,Q=W.sub.1. The orthogonal
Hadamard sequence is allocated to each channel based on the
above-described operation, and if other channels remain which are
not allocated the orthogonal Hadamard sequence by the
above-described operation then any row or column vector from the
Hadamard matrix can be selected.
[0127] FIG. 11 illustrates an embodiment of a permuted orthogonal
complex spreading apparatus with two input channels. In this case,
the data of two channels, namely, the pilot channel and the data of
traffic channels are multiplied by the gain and orthogonal Hadamard
sequence. The two channel signals are then inputted into the
complex multiplier 900 in the complex form and the orthogonal
Hadamard sequence of the complex form is multiplied by the complex
multiplier 900.
[0128] FIG. 12 illustrates an embodiment of a permuted orthogonal
complex spreading apparatus with three input channels. The pilot
channel and signaling channel are allocated to the first orthogonal
Hadamard sequence multiplier 700 and the traffic channel is
allocated to the second orthogonal Hadamard sequence multiplier
700.
[0129] FIG. 13A illustrates an embodiment of a permuted orthogonal
complex spreading apparatus with four input channels. In FIG. 13B,
the system may be constructed so that the input data (traffic 1 and
traffic 2) have identical gains
(.alpha..sub.31=.alpha..sub.12).
[0130] FIG. 14A and 14B illustrate an embodiment of a permuted
orthogonal complex spreading apparatus with five input
channels.
[0131] In FIG. 14B, when the data (Traffic) is separated into two
channel data (Traffic 1) and (Traffic 2) and then is inputted, the
gains adapted to each channel are identical (.alpha.31=.alpha.12
).
[0132] FIG. 15A is a phase trajectory view of an OCQPSK, according
to the present invention. FIG. 15B is a phase trajectory view of a
POCQPSK, according to the present invention. FIG. 15C is a phase
trajectory view of a complex spreading method, according to PN
complex spreading method of the prior art.
[0133] The shapes of the trajectories around the zero point are
different when comparing FIGS. 15A, 15B and 15C. This difference
indicates the difference between the three methods.
[0134] FIG. 7 illustrates a statistical distribution of a peak
power-to-average power ratio of the CDMA ONE method compared to the
OCQPSK and POSQPSK methods.
[0135] In order to provide the identical condition the following
has to occur: power level of the signal channel is controlled to be
the same as the power level of the communication channel; power
level of the pilot channel is controlled to be lower than the power
level of the communication channel by 4dB.
[0136] In the case of the POCQPSK, in the first block 600 of FIG.
9, W.sub.M,11=W.sub.0, and W.sub.M,21=W.sub.2 are implemented and
in the second block 700 W.sub.M,12=W.sub.4, and W.sub.M,I=W.sub.0
and W.sub.M,Q=W.sub.1 are implemented. For the value of P, the
spreading code is used so that two consecutive sequences have an
identical value.
[0137] For example, the probability that the instantaneous power
exceeds the average power value (0dB) by 4dB is 0.1% based on
POCQPSK, and the complex spreading method is 2%. Therefore, in view
of the power efficiency, the method in accordance with the present
invention, is a new modulation method having excellent
characteristics.
[0138] As described above, in the OCQPSK in accordance with the
present invention, the first data and the second data are
multiplied by the gain and orthogonal code, and the resultant
values are complex-summned, and the complex summed value is
complex-multiplied by a complex type orthogonal code. A method is
utilized where the information of the multichannel of the identical
structure is summed and then spread. Therefore, this method
statistically reduces the peak power-to-average power ratio to the
desired range.
[0139] Additionally, in the POCQPSK the data of the first block and
the data of the second block are multiplied by the gain and the
orthogonal code, respectively, and the permuted orthogonal
spreading code of the complex type is complex-multiplied and then
spread. Therefore, this method statistically reduces the peak
power-to-average power ratio to the desired range. Utilizing the
combined orthogonal Hadamard sequence, it is possible to decrease
the phase dependency based in multichannel and multi-user
interference.
[0140] Although, the preferred embodiments of the present invention
have been disclosed for illustrative purposes those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as recited in the accompanying claims.
* * * * *