U.S. patent application number 13/303489 was filed with the patent office on 2012-05-10 for apparatus and method for modulating data message by employing orthogonal variable spreading factor (ovsf) codes in mobile communication system.
This patent application is currently assigned to Electronics and Telecommunications Research Institute. Invention is credited to Seung-Chan Bang, Jong-Suk Chae, Jae-Heung Kim, Jung-Im Kim, Tae-Joong Kim, Hyuck-Jae Lee, Narm-Hee Lee, Jae-Ryong Shim.
Application Number | 20120114017 13/303489 |
Document ID | / |
Family ID | 37035130 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120114017 |
Kind Code |
A1 |
Bang; Seung-Chan ; et
al. |
May 10, 2012 |
Apparatus and Method for Modulating Data Message By Employing
Orthogonal Variable Spreading Factor (OVSF) Codes in Mobile
Communication System
Abstract
A method for converting source data to a channel-modulated
signal having a plurality of pairs of in-phase (I) and
quadrature-phase (Q) data in a mobile station, wherein the mobile
station uses at least one channel, includes the steps of: a)
encoding the source data to generate at least one data part and a
control part; b) generating at least one spreading code to be
allocated to the channel, wherein each spreading code is selected
on the basis of a data rate of the data part and the control part
and spreading codes are selected so that two consecutive pairs of
the I and Q data are correspondent to two points located on same
point or symmetrical with respect to a zero point on a phase
domain; and c) spreading the control part and the data part by
using the spreading code, to thereby generate the channel-modulated
signal.
Inventors: |
Bang; Seung-Chan; (Taejon,
KR) ; Kim; Tae-Joong; (Taejon, KR) ; Kim;
Jae-Heung; (Taejon, KR) ; Kim; Jung-Im;
(Taejon, KR) ; Chae; Jong-Suk; (Taejon, KR)
; Lee; Hyuck-Jae; (Taejon, KR) ; Shim;
Jae-Ryong; (Taejon, KR) ; Lee; Narm-Hee;
(Taejon, KR) |
Assignee: |
Electronics and Telecommunications
Research Institute
Taejon
KR
|
Family ID: |
37035130 |
Appl. No.: |
13/303489 |
Filed: |
November 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12259072 |
Oct 27, 2008 |
8121173 |
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13303489 |
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11618361 |
Dec 29, 2006 |
7586973 |
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12259072 |
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09584189 |
May 31, 2000 |
7443906 |
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11618361 |
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Current U.S.
Class: |
375/146 ;
375/E1.001 |
Current CPC
Class: |
H04J 13/0044 20130101;
H04J 13/10 20130101; H04B 1/7073 20130101; H04J 13/20 20130101;
H04B 2201/70703 20130101 |
Class at
Publication: |
375/146 ;
375/E01.001 |
International
Class: |
H04B 1/69 20110101
H04B001/69 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 1999 |
KR |
1999-19813 |
Aug 30, 1999 |
KR |
1999-36383 |
Claims
1-82. (canceled)
83. A mobile station, capable of using a plurality of data channels
and a control channel, that converts source data to a
channel-modulated signal, the mobile station comprising one or more
processors programmed to: encode the source data to generate a
plurality of data parts and a control part, wherein the data parts
are allocated to the data channels and the control part is
allocated to the control channel; generate spreading codes to be
allocated to the channels, wherein each of the spreading codes is
generated on the basis of a spreading factor related to a data rate
for the respective channel and a code number for the respective
channel, wherein the step of generating spreading codes to be
allocated to the channels comprises: consecutively producing a
count value in synchronization with a clock signal, in response to
the count value and the spreading factor for each data channel,
generating the spreading code to be allocated to each data channel,
and in response to the count value and the spreading factor for the
control channel, generating the spreading code to be allocated to
the control channel; and spread the control channel and the data
channels using the allocated spreading codes to thereby generate
the channel-modulated signal, wherein: the spreading codes
correspond to orthogonal variable spreading factor (OVSF) codes,
the spreading code allocated to the control channel is represented
by C.sub.256,0, where 256 denotes the spreading factor and 0 the
code number, the spreading codes allocated to first and second data
channels are represented by C.sub.4, 1.
84. The mobile station of claim 83, wherein the step of generating
the spreading code to be allocated to each data channel comprises:
in response to the count value, carrying out a first logical
operation with the spreading factor for the respective data channel
and the code number for the respective data channel, to thereby
generate the spreading code to be allocated to the respective data
channel; and outputting the spreading code to be allocated to the
respective data channel in response to a first select signal.
85. The mobile station of claim 84, wherein a code number of
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, a count
value of B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0,
and a predetermined spreading factor are received for the first
logical operation, and wherein the first logical operation is i = 0
N - 1 .sym. I i B N - 1 - i ##EQU00003## if the predetermined
spreading factor is 2.sup.N where N is 2 to 8.
86. The mobile station of claim 84, wherein the code number to be
used in the first logical operation is represented by
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, wherein
the count value to be used in the first logical operation is
represented by
B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0, and
wherein the second logical operation is i = 0 N - 1 .sym. I i B N -
1 - i ##EQU00004## where the spreading factor is 2.sup.N and N is 2
to 8.
87. The mobile station of claim 86, wherein the step of generating
the spreading code to be allocated to the control channel
comprises: in response to the count value, carrying out a second
logical operation with the spreading factor for the control channel
and the code number for the control channel, to thereby generate
the spreading code to be allocated to the control channel; and
outputting the spreading code to be allocated to the control
channel in response to a second select signal.
88. The mobile station of claim 87, wherein the code number to be
used in the second logical operation is represented by
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, wherein
the count value to be used in the second logical operation is
represented by
B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0, and
wherein the second logical operation is i = 0 N - 1 .sym. I i B N -
1 - i ##EQU00005## where the spreading factor is 2.sup.N and N is 2
to 8.
89. The mobile station of claim 88, wherein C.sub.4, 1 represents
{1, 1, -1, -1}.
90. The mobile station of claim 89, wherein the one or more
processors are programmed to: in response to the spreading factor,
generate the code numbers for the channels.
91. The mobile station of claim 83, wherein the step of generating
the spreading code to be allocated to the control channel
comprises: in response to the count value, carrying out a second
logical operation with the spreading factor for the control channel
and the code number for the control channel, to thereby generate
the spreading code to be allocated to the control channel; and
outputting the spreading code to be allocated to the control
channel in response to a second select signal.
92. The mobile station of claim 91, wherein a code number of
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, a count
value of B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0,
and a predetermined spreading factor are received for the second
logical operation, and wherein the second logical operation is i =
0 N - 1 .sym. I i B N - 1 - i ##EQU00006## if the predetermined
spreading factor is 2.sup.N where N is 2 to 8.
93. The mobile station of claim 91, wherein the code number to be
used in the second logical operation is represented by
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, wherein
the count value to be used in the second logical operation is
represented by
B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0, and
wherein the second logical operation is i = 0 N - 1 .sym. I i B N -
1 - i ##EQU00007## where the spreading factor is 2.sup.N and N is 2
to 8.
94. The mobile station of claim 83, wherein C.sub.4, 1 represents
{1, 1, -1, -1}.
95. The mobile station of claim 83, wherein C.sub.4, 1 is
represented by a series of a pair of positive one integer and a
pair of negative one integer.
96. The mobile station of claim 83, wherein the one or more
processors are programmed to: in response to the spreading factor,
generate the code numbers for the channels.
97. A mobile station as in any one of claim 83-96, wherein the
channel-modulated signal has a plurality of pairs of in-phase (I)
and quadrature-phase (Q) data and wherein the spreading codes are
selected so that two consecutive pairs of the I and Q data are
correspondent to two points located on the same point or
symmetrical with respect to a zero point on a phase domain.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and method for
modulating a data message in a mobile communication system; and,
more particularly, to an apparatus and method for modulating a data
message by employing orthogonal variable spreading factor (OVSF)
codes in a mobile communication system.
DESCRIPTION OF THE PRIOR ART
[0002] Generally, a mobile communication system such as an
international mobile telecommunication-2000 (IMT-2000) system is
capable of providing various services of good quality and large
capacity, an international roaming and so on. The mobile
communication system can be applicable to high-speed data and
multimedia services such as an Internet service and an electronic
commerce service. The mobile communication system carries out
orthogonal spread with respect to multiple channels. The mobile
communication system allocates the orthogonal spread channels to an
in-phase (I) branch and a quadrature-phase (Q) branch. A
peak-to-average power ratio (PAPR) needed to simultaneously
transmit I-branch data and Q-branch data affects power efficiency
of a mobile station and a battery usage time of the mobile
station.
[0003] The power efficiency and the battery usage time of the
mobile station are closely related to a modulation scheme of the
mobile station. As a modulation standard of IS-2000 and
asynchronous wideband-CDMA, the modulation scheme of orthogonal
complex quadrature phase shift keying (OCQPSK) has been adopted.
The modulation scheme of OCQPSK is disclosed in an article by
JaeRyong Shim and SeungChan Bang: `Spectrally Efficient Modulation
and Spreading Scheme for CDMA Systems` in electronics letters, 12
Nov. 1998, vol. 34, No. 23, pp. 2210-2211.
[0004] As disclosed in the article, the mobile station carries out
the orthogonal spread by employing a Hadamard sequence as a Walsh
code in the modulation scheme of the OCQPSK. After the orthogonal
spread, I and Q channels are spread by a Walsh rotator and a
spreading code, e.g., a pseudo noise (PN) code, a Kasami code, a
Gold code and so on.
[0005] Further, as for multiple channels, the mobile station
carries out the orthogonal spread by employing different Hardamard
sequences. After the orthogonal spread, the orthogonal spread
channels are coupled to I and Q branches. Then, the orthogonal
spread channels coupled to the I branch and the orthogonal spread
channels coupled to the Q branch is separately summed. The I and Q
branches are scrambled by the Walsh rotator and the scrambling
code. However, there is a problem that the above-mentioned
modulation scheme can not effectively reduce the PAPR in the mobile
communication system.
SUMMARY OF THE INVENTION
[0006] It is, therefore, an object of the present invention to
provide an apparatus and method for modulating a data message that
is capable of improving a power efficiency of a mobile station by
reducing a peak-to-average power ratio in a mobile communication
system.
[0007] In accordance with an embodiment of an aspect of the present
invention, there is provided an apparatus for converting source
data to a channel-modulated signal having a plurality of pairs of
in-phase (I) and quadrature-phase (Q) data in a mobile station,
wherein the mobile station uses at least one channel, comprising:
channel coding means for encoding the source data to generate at
least one data part and a control part; code generating means for
generating at least one spreading code to be allocated to the
channel, wherein each spreading code is selected on the basis of a
data rate of the data part and the control part and spreading codes
are selected so that two consecutive pairs of the I and Q data are
correspondent to two points located on same point or symmetrical
with respect to a zero point on a phase domain; and spreading means
for spreading the control part and the data part by using the
spreading code, to thereby generate the channel-modulated
signal.
[0008] In accordance with another embodiment of the aspect of the
present invention, there is provided an apparatus for converting
source data to a Channel-modulated signal having a plurality of
pairs of in-phase (I) and quadrature-phase (Q) data in a mobile
station, wherein the mobile station uses N number of channels where
N is a positive integer, comprising: channel coding means for
encoding the source data to generate (N-1) number of data parts and
a control part; code generating means for generating N number of
spreading codes to be allocated to the channels, wherein each
spreading code is selected on the basis of a data rate of each data
part and the control part and the spreading codes are selected so
that two consecutive pairs of the I and Q data are correspondent to
two points located on same point or symmetrical with respect to a
zero point on a phase domain; and spreading means for spreading the
control part and the data parts by using the spreading codes, to
thereby generate the channel-modulated signal.
[0009] In accordance with an embodiment of another aspect of the
present invention, there is provided a mobile station for
converting source data to a channel-modulated signal having a
plurality of pairs of in-phase (I) and quadrature-phase (Q) data,
wherein the mobile station uses N number of channels where N is a
positive integer, comprising: channel coding means for encoding the
source data to generate (N-1) number of data parts and a control
part; code generating means for generating N number of spreading
codes to be allocated to the first and the second channels, wherein
each spreading code is selected on the basis of a data rate of each
data part and the control part and the spreading codes are selected
so that two consecutive pairs of the I and Q data are correspondent
to two points located on same point or symmetrical with respect to
a zero point on a phase domain; and spreading means for spreading
the control part and the data parts by using the spreading codes,
to thereby generate the channel-modulated signal.
[0010] In accordance with an embodiment of further another aspect
of the present invention, there is provided a method for converting
source data to a channel-modulated signal having a plurality of
pairs of in-phase (I) and quadrature-phase (Q) data in a mobile
station, wherein the mobile station uses at least one channel,
comprising the steps of: a) encoding the source data to generate at
least one data part and a control part; b) generating at least one
spreading code to be allocated to the channel, wherein each
spreading code is selected on the basis of a data rate of the data
part and the control part and spreading codes are selected so that
two consecutive pairs of the I and Q data are correspondent to two
points located on same point or symmetrical with respect to a zero
point on a phase domain; and c) spreading the control part and the
data part by using the spreading code, to thereby generate the
channel-modulated signal.
[0011] In accordance with another embodiment of further another
aspect of the present invention, there is provided a method for
converting source data to a channel-modulated signal having a
plurality of pairs of in-phase (I) and quadrature-phase (Q) data in
a mobile station, wherein the mobile station uses N number of
channels where N is a positive integer, comprising: a) encoding the
source data to generate (N-1) number of data parts and a control
part; b) generating N number of spreading codes to be allocated to
the channels, wherein each spreading code is selected on the basis
of a data rate of each data part and the control part and the
spreading codes are selected so that two consecutive pairs of the I
and Q data are correspondent to two points located on same point or
symmetrical with respect to a zero point on a phase domain; and c)
spreading the control part and the data parts by using the
spreading codes, to thereby generate the channel-modulated
signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above and other objects and features of the instant
invention will become apparent from the following description of
preferred embodiments taken in conjunction with the accompanying
drawings, in which:
[0013] FIG. 1 is a block diagram illustrating a mobile station to
which the present invention is applied;
[0014] FIG. 2 is an exemplary view illustrating a tree structure of
spreading codes applied to the present invention;
[0015] FIG. 3 is an exemplary block diagram depicting a modulator
shown in FIG. 1 in accordance with the present invention;
[0016] FIG. 4 is a block diagram describing a spreading code
generator shown in FIG. 3;
[0017] FIG. 5 is an exemplary diagram illustrating a case where a
mobile station uses two channels;
[0018] FIG. 6 is an exemplary diagram depicting a case where
multiple mobile stations share a common complex-valued scrambling
code;
[0019] FIG. 7 is an exemplary diagram showing a case where a mobile
station uses multiple channels;
[0020] FIG. 8 is a first exemplary view describing a desirable
phase difference between rotated points on a phase domain where a
Walsh rotator rotates points at consecutive chips;
[0021] FIG. 9 is a second exemplary view showing a desirable phase
difference between rotated points on a phase domain where a Walsh
rotator rotates points at consecutive chips;
[0022] FIG. 10 is a first exemplary view depicting an undesirable
phase difference between rotated points on a phase domain where a
Walsh rotator rotates points at consecutive chips;
[0023] FIGS. 11 and 12 are third exemplary views illustrating a
desirable phase difference between rotated points on a phase domain
where a Walsh rotator rotates points at consecutive chips;
[0024] FIGS. 13 and 14 are second exemplary views illustrating an
undesirable phase difference between rotated points on a phase
domain where a Walsh rotator rotates points at consecutive
chips;
[0025] FIG. 15 is a graphical diagram describing the probability of
peak power to average power; and
[0026] FIGS. 16 to 22 are flowcharts illustrating a method for
modulating a data message in a mobile station in accordance with
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring to FIG. 1, there is shown a block diagram
illustrating a mobile station to which the present invention is
applied. As shown, the mobile station includes a user interface 20,
a central processing unit (CPU) 180, a modem 12, a source codec 30,
a frequency converter 80, a user identification module 50 and an
antenna 70. The modem 12 includes a channel codec 13, a modulator
100 and a demodulator 120. The channel codec 13 includes an encoder
110 and a decoder 127.
[0028] The user interface 20 includes a display, a keypad and so
on. The user interface 20, coupled to the CPU 180, generates a data
message in response to a user input from a user. The user interface
20 sends the data message to the CPU 180.
[0029] The user identification module 50, coupled to the CPU 180,
sends user identification information as a data message to the CPU
180. The source codec 30, coupled to the CPU 180 and the modem 12,
encodes source data, e.g., video, voice and so on, to generate the
encoded source data as a data message. Then, the source codec 30
sends the encoded source data as the data message to the CPU 180 or
the modem 12. Further, the source codec 30 decodes the data message
from the CPU 180 or the modem 12 to generate the source data, e.g.,
video, voice and so on. Then, the source codec 30 sends the source
data to the CPU 180.
[0030] The encoder 110, contained in the channel codec 13, encodes
the data message from the CPU 180 or the source codec 30 to
generate one or more data parts. Then, the encoder 110 generates a
control part.
[0031] The encoder 110 sends the one or more data parts to the
modulator 100. The modulator 100 modulates the one or more data
parts and the control part to generate I and Q signals as baseband
signals. The frequency converter 80 converts the baseband signals
to intermediate frequency (IF) signals in response to a conversion
control signal from the CPU 180. After converting the baseband
signals to the IF signals, the frequency converter 80 converts the
IF signals to radio frequency (RF) signals. The frequency converter
80 sends the RF signals to the antenna 70. Further, the frequency
converter 80 controls a gain of the RF signals. The antenna 70
sends the RF signals to a base station (not shown).
[0032] The antenna 70 sends the RF signals from the base station to
the frequency converter 80. The frequency converter 80 converts the
RF signals to the IF signals. After converting the RF signals to
the IF signals, the frequency converter 80 converts the IF signals
to the baseband signals as the I and Q signals. The demodulator 90
demodulates the I and Q signals to generate the one or more data
parts and the control part. The decoder 127, contained in the
channel codec 13, decodes the one or more data parts and the
control part to generate the data message. The decoder 127 sends
the data message to the CPU 180 or the source codec 30.
[0033] Referring to FIG. 2, there is shown an exemplary view
illustrating a tree structure of spreading codes as orthogonal
variable spreading factor (OVSF) codes applied to the present
invention. As shown, a spreading code is determined by a spreading
factor (SF) and a code number in a code tree, wherein the spreading
code is represented by C.sub.SF, code number. C.sub.SF, code number
is made up of a real-valued sequence. The SF is 2.sup.N where N is
0 to 8, and the code number is 0 to 2.sup.N-1.
[ C 2 , 0 C 2 , 1 ] = [ C 1 , 0 C 1 , 0 C 1 , 0 - C 1 , 0 ] = [ 1 1
1 - 1 ] where C 1 , 0 = 1 Eq . ( 1 ) [ C 2 ( N + 1 ) , 0 C 2 ( N +
1 ) , 1 C 2 ( N + 1 ) , 2 C 2 ( N + 1 ) , 3 C 2 ( N + 1 ) , 2 ( N +
1 ) - 2 C 2 ( N + 1 ) , 2 ( N + 1 ) - 1 ] = [ C 2 N , 0 C 2 N , 0 C
2 N , 0 - C 2 N , 0 C 2 N , 1 C 2 N , 1 C 2 N , 1 - C 2 N , 1 C 2 N
, 2 N - 1 C 2 N , 2 N - 1 C 2 N , 2 N - 1 - C 2 N , 2 N - 1 ] where
N is 1 to 7 Eq . ( 2 ) ##EQU00001##
[0034] For example, a spreading code having an SF of 8 and a code
number of 1 is represented by C.sub.8, 1={1, 1, 1, 1, -1, -1, -1,
-1} according to Eqs. (1) and (2). In case where the SF is more
than 2, the spreading codes are grouped by two groups, including a
first group and a second group according to a code number sequence.
The first group includes the spreading codes with the SF and code
numbers of 0 to SF/2-1 and the second group includes the spreading
codes with the SF and code numbers of SF/2 to SF-1. Therefore, the
number of spreading codes contained in the first group is the same
as that of spreading codes contained in the second group.
[0035] Each spreading code contained in the first or second group
is made up of real values. Each spreading code contained in the
first or second group can be employed in an OCQPSK modulation
scheme. It is preferred that a spreading code, contained in the
first group, is selected for the OCQPSK modulation scheme. However,
where a spreading code, contained in the second group, is
multiplied by another spreading code with a minimum code number,
i.e., SF/2, contained in the second group, the multiplication of
the spreading codes, contained in the second group, becomes the
same as a spreading code contained in the first group. Accordingly,
the multiplication of the spreading codes contained in the second
group is represented by a spreading code of the first group. As a
result, all the spreading codes, i.e., OVSF codes, of the first and
second groups are useful for reducing the peak-to-average power
ratio (PAPR) of the mobile station.
[0036] Referring to FIG. 3, there is shown a block diagram
depicting a modulator shown in FIG. 1 in accordance with the
present invention. The mobile communication system includes a base
station and a mobile station employing a plurality of channels,
wherein the mobile station includes the modulator. The channels
include a control channel and one or more data channels.
[0037] The one or more data channels include a physical random
access channel (PRACH), a physical common packet channel (PCPCH)
and dedicated physical channel (DPCH). In a PRACH or PCPCH
application, a control channel and only one data channel, i.e.,
PRACH or PCPCH, are coupled between the encoder 110 and the
spreader 130. The DPCH includes dedicated physical data channels
(DPDCHs). In a DPCH application, a dedicated physical control
channel (DPCCH) as a control channel and up to six data channels,
i.e., DPDCH 1 to DPDCH 5 are coupled between the encoder 110 and
the spreader 130. As shown, a modulator 100 includes an encoder
110, a code generator 120, a spreader 130, a scrambler 140, a
filter 150, a gain adjuster 160 and an adder 170.
[0038] The encoder 110 encodes the data message to be transmitted
to the base station to generate one or more data parts. The encoder
110 generates a control part having a control information. The
encoder 110 evaluates an SF based on a data rate of the one or more
data parts.
[0039] The CPU 180, coupled to the encoder 110, receives the SF
related to the one or more data parts from the encoder 110. The CPU
180 produces one or more code numbers related to the one or more
data parts and an SF and a code number related to the control
part.
[0040] The code generator 120 includes a spreading code generator
121, a signature generator 122 and a scrambling code generator 123.
The code generator 120, coupled to the CPU 180, generates spreading
codes, i.e., C.sub.d1 to C.sub.dn and C.sub.c, a signature S and a
complex-valued scrambling code. The spreading code generator 121,
coupled to the CPU 180 and the spreader 130, generates the
spreading codes in response to the SF and the one or more code
numbers related to the one or more data parts and an SF and a code
number related to the control part from the CPU 180. The spreading
code generator 121 sends the spreading codes to the spreader
130.
[0041] The signature generator 122, coupled to the CPU 180 and the
spreading code generator 121, generates the signature S to send the
signature S to the spreading code generator 121. The scrambling
code generator 123 generates the complex-valued scrambling code to
send the complex-valued scrambling code to the scrambler 140.
[0042] The spreader 130 spreads the control part and the one or
more data parts from the encoder 110 by the spreading codes from
the code generator 120.
[0043] The scrambler 140 scrambles the complex-valued scrambling
code, the one or more data parts and the control part spread by the
spreader 130, thereby generating scrambled signals. The scrambler
140 includes a Walsh rotator, which is typically employed in the
OCQPSK modulation scheme. The Walsh rotator rotates the one or more
data parts and the control part spread by the spreader 130.
[0044] The filter 150, i.e., a root raised cosine (PRC) filter,
pulse-shapes the scrambled signals to generate pulse-shaped
signals.
[0045] The gain adjuster 160 multiplies each of the pulse-shaped
signals by the gain of each channel, thereby generating
gain-adjusted signals.
[0046] The adder 170 sums the gain-adjusted signals related to an I
branch or the gain-adjusted signals related to a Q branch, to
thereby generate a channel-modulated signal having a plurality of
pairs of I and Q data in the mobile station.
[0047] Referring to FIG. 4, there is shown a block diagram
describing a spreading code generator shown in FIG. 3. As shown,
the spreading code generator includes a storage device 210, an
8-bit counter 220, a plurality of logical operators 231 and 233 and
a plurality of multiplexers 232 and 234.
[0048] The storage device 210 includes one or more registers 211
related to the one or more data parts and a register 212 related to
the control part. The one or more registers 211 stores an SF and
code numbers related to the one or more data parts sent from the
CPU 180 shown in FIG. 3. The register 212 stores an SF and a code
number related to the control part sent from the CPU 180.
[0049] The 8-bit counter 220 consecutively produces a count value
of B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0 as
8-bit count value in synchronization with a clock signal CHIP_CLK
issued from an external circuit, wherein B.sub.0 to B.sub.7 are
made up of a binary value of 0 or 1, respectively.
[0050] The one or more logical operators 231 carry out one or more
logical operations with the SF and the code numbers related to the
one or more data parts stored in the one or more register 211,
thereby generating the spreading codes related to the one or more
data parts.
[0051] A code number is represented by
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0, wherein
I.sub.0 to I.sub.7 are the binary value of 0 or 1,
respectively.
[0052] The logical operator 233 carries out a logical operation
with the SF and the code number of
I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0 related to
the control part stored in the register 212, thereby generating a
spreading code related to the control part.
i = 0 N - 2 .sym. I i B N - 1 - i where 2 .ltoreq. N .ltoreq. 8 Eq
. ( 3 ) ##EQU00002##
[0053] where "" denotes a multiplication in modulo 2 and
.pi..sup..sym. denotes an exclusive OR operation. Each logical
operator 231 or 233 carries out a logical operation according to
Eq. (3) where SF=2.sup.N.
[0054] If the SF is 256, each logical operator 231 or 233 carries
out a logical operation of
B.sub.7I.sub.0.sym.B.sub.6I.sub.1.sym.B.sub.5I.sub.2.sym.B.sub.4I.sub.3.s-
ym.B.sub.3I.sub.4.sym.B.sub.2I.sub.5.sym.B.sub.1I.sub.6.sym.B.sub.0I.sub.7
[0055] If the SF is 128, each logical operator 231 or 233 carries
out a logical operation of
B.sub.6I.sub.0.sym.B.sub.5I.sub.1.sym.B.sub.4I.sub.2.sym.B.sub.3I.sub.3.s-
ym.B.sub.2I.sub.4.sym.B.sub.1I.sub.5.sym.B.sub.0I.sub.6.
[0056] If the SF is 64, each logical operator 231 or 233 carries
out a logical operation of
B.sub.5I.sub.0.sym.B.sub.4I.sub.1.sym.B.sub.3I.sub.2.sym.B.sub.2I.sub.3.s-
ym.B.sub.1I.sub.4.sym.B.sub.0I.sub.5.
[0057] If the SF is 32, each logical operator 231 or 233 carries
out a logical operation of
B.sub.4I.sub.0.sym.B.sub.3I.sub.1.sym.B.sub.2I.sub.2.sym.B.sub.1I.sub.3.s-
ym.B.sub.0I.sub.4.
[0058] If the SF is 16, each logical operator 231 or 233 carries
out a logical operation of
B.sub.3I.sub.0.sym.B.sub.2I.sub.1.sym.B.sub.1I.sub.2.sym.B.sub.0I.sub.3.
[0059] If the SF is 8, each logical operator 231 or 233 carries out
a logical operation of
B.sub.2I.sub.0.sym.B.sub.1I.sub.1.sym.B.sub.0I.sub.2.
[0060] If the SF is 4, each logical operator 231 or 233 carries out
a logical operation of B.sub.1I.sub.0.sym.B.sub.0I.sub.1.
[0061] The one or more multiplexers 232 selectively output the one
or more spreading codes from the one or more logical operators 231
in response to one or more select signals as the SF related to the
one or more data parts.
[0062] The multiplexer 234 selectively outputs the spreading code
from the logical operator 233 in response to a select signal as the
SF related to the control part.
[0063] Referring to FIG. 5, there is shown an exemplary diagram
illustrating a case where a mobile station uses two channels.
[0064] As shown, when the mobile station uses the two channels and
SF=2.sup.N where N=2 to 8, the spreading code generator 121
generates a spreading code of C.sub.SF, SF/4 to be allocated to the
DPDCH or the PCPCH as a data channel. Further, the spreading code
generator 121 generates a spreading code of C.sub.256, 0 to be
allocated to the DPCCH or the control channel. Then, the spreader
130 spreads the DPDCH or the PCPCH by the spreading code of
C.sub.SF, SF/4. Further, The spreader 130 spreads the control
channel by the spreading code of C.sub.256, 0. At this time, the
scrambling code generator 123 generates a complex-valued scrambling
code assigned to the mobile station. Further, the complex-valued
scrambling code can be temporarily reserved in the mobile
station.
[0065] Referring to FIG. 6, there is shown an exemplary diagram
depicting a case where multiple mobile stations share a common
complex-valued scrambling code in the PRACH application.
[0066] As shown, where the multiple mobile stations share a common
complex-valued scrambling code and SF=2.sup.N where N=5 to 8 and
S=1 to 16, the spreading code generator 121 generates a spreading
code of C.sub.SF, SF(S-1)/16 to be allocated to the PRACH. Further,
the spreading code generator 121 generates a spreading code of
C.sub.256, 16(S-1)+15 to be allocated to the control channel.
[0067] Then, the spreader 130 spreads the PRACH by the spreading
code of C.sub.SF, SF(S-1)/16. Also, the spreader 130 spreads the
control channel by the spreading code of C.sub.256, 16(S-1)+15. At
this time, the scrambling code generator 123 generates a common
complex-valued scrambling code.
[0068] Referring to FIG. 7, there is shown an exemplary diagram
showing a case where a mobile station uses multiple channels. As
shown, where the mobile station uses one control channel and two
data channels and the SF related to the two data channels is 4, the
spreading code generator 121 generates a spreading code of
C.sub.256, 0 to be allocated to the DPCCH. Further, the spreading
code generator 121 generates a spreading code of C.sub.4, 1
allocated to the DPDCH 1. Furthermore, the spreading code generator
121 generates a spreading code of C.sub.4, 1 allocated to the DPDCH
2.
[0069] Then, the spreader 130 spreads the DPDCH 1 by the spreading
code of C.sub.4, 1. Further, the spreader 130 spreads the DPDCH 2
by the spreading code of C.sub.4, 1. Furthermore, the spreader 130
spreads the DPCCH by the spreading code of C.sub.256, 0. At this
time, the scrambling code generator 123 generates a complex-valued
scrambling codes assigned to the mobile station.
[0070] As shown, where the mobile station uses one control channel
and three data channels and the SF related to the three data
channels is 4, the spreading code generator 121 further generates a
spreading code of C.sub.4, 3 to be allocated to the DPDCH 3. Then,
the spreader 130 further spreads the DPDCH 3 by the spreading code
of C.sub.4, 3.
[0071] As shown, where the mobile station uses one control channel
and four data channels and the SF related to the four data channels
is 4, the spreading code generator 121 further generates a
spreading code of C.sub.4, 3 to be allocated to the DPDCH 4. Then,
the spreader 130 further spreads the DPDCH 4 by the spreading code
of C.sub.4, 3.
[0072] As shown, where the mobile station uses one control channel
and five data channels and the SF related to the five data channels
is 4, the spreading code generator 121 further generates a
spreading code of C.sub.4, 2 to be allocated to the DPDCH 5. Then,
the spreader 130 further spreads the DPDCH 5 by the spreading code
of C.sub.4, 2.
[0073] As shown, where the two mobile station uses one control
channel and six data channels and the SF related to the six data
channels is 4, the spreading code generator 121 further generates a
spreading code of C.sub.4, 2 to be allocated to the DPDCH 6. Then,
the spreader 130 further spreads the DPDCH 6 by the spreading code
of C.sub.4, 2.
[0074] Referring to FIG. 8, there is shown a first exemplary view
describing a desirable phase difference between rotated points on a
phase domain where a Walsh rotator rotates points at consecutive
chips.
[0075] As shown, in case where an SF is 4 and a code number is 0, a
spreading code of C.sub.4, 0 is represented by {1, 1, 1, 1}.
Further, in case where the SF is 4 and a code number is 1, a
spreading code of C.sub.4, 1 is represented by {1, 1, -1, -1}.
[0076] Assume that two channels are spread by the spreading code of
C.sub.4, 0={1, 1, 1, 1} and the spreading code of C.sub.4, 1={1, 1,
-1, -1}, respectively. At this time, real values contained in the
spreading code of C.sub.4, 0={1, 1, 1, 1} are represented by points
on a real axis of a phase domain. Further, real values contained in
the spreading code of C.sub.4, 1={1, 1, -1, -1} are represented by
points on an imaginary axis of the phase domain.
[0077] At a first or second chip, a point {1, 1}, i.e., a point
{circle around (1)} or {circle around (2)}, is designated on the
phase domain by first or second real values contained in the
spreading codes of C.sub.4, 0 and C.sub.4, 1. At a third or fourth
chip, a point {1, -1}, i.e., a point {circle around (3)} or {circle
around (4)}, is designated on the phase domain by third or fourth
real values contained in the spreading codes of C.sub.4, 0 and
C.sub.4, 1. The points {circle around (1)} and {circle around (2)}
are positioned on the same point as each other. Also, the points
{circle around (3)} and {circle around (4)} are positioned on the
same point as each other. Where the Walsh rotator rotates the
points at chips, the points are rotated by a predetermined phase,
respectively.
[0078] For example, where the Walsh rotator rotates the point
{circle around (1)} or {circle around (3)} at an odd chip, the
point {circle around (1)} or {circle around (3)} is rotated to a
clockwise direction by a phase of 45.degree.. Further, where the
Walsh rotator rotates the point {circle around (2)} or {circle
around (4)} at an even chip, the point {circle around (2)} or
{circle around (4)} is rotated to a counterclockwise direction by
the phase of 45.degree.. After rotating the points {circle around
(1)} and {circle around (2)} or the points {circle around (3)} and
{circle around (4)} at the odd and even chips as two consecutive
chips, a phase difference between the rotated points {circle around
(1)}' and {circle around (2)}' or the rotated points {circle around
(3)}' and {circle around (4)}' becomes 90.degree.. Where the phase
difference between the rotated points {circle around (1)}' and
{circle around (2)}' or the rotated points {circle around (3)}' and
{circle around (4)}' becomes 90.degree., a peak-to-average power
ratio (PAPR) of a mobile station can be reduced.
[0079] For another example, where the Walsh rotator rotates the
point {circle around (1)} or {circle around (3)} at an odd chip,
the point {circle around (1)} or {circle around (3)} is rotated to
the counterclockwise direction by the phase of 45.degree.. Further,
where the Walsh rotator rotates the point {circle around (2)} or
{circle around (4)} at an even chip, the point {circle around (2)}
or {circle around (4)} is rotated to the clockwise direction by the
phase of 45.degree..
[0080] After rotating the points {circle around (1)} and {circle
around (2)} a or the points {circle around (3)} and {circle around
(4)} at the odd and even chips as two consecutive chips, a phase
difference between the rotated points {circle around (1)}'' and
{circle around (2)}'' or the rotated points {circle around (3)}''
and {circle around (4)}'' becomes 90.degree.. Where the phase
difference between the rotated points {circle around (1)}'' and
{circle around (2)}'' or the rotated points {circle around (3)}''
and {circle around (4)}'' becomes 90.degree., the peak-to-average
power ratio of the mobile station can be reduced.
[0081] Referring to FIG. 9, there is shown a second exemplary view
showing a desirable phase difference between rotated points on a
phase domain where a Walsh rotator rotates points at consecutive
chips.
[0082] First, assume that two channels are spread by a spreading
code of C.sub.4, 2={1, -1, 1, -1} and a spreading code of C.sub.4,
3={1, -1, -1, 1}, respectively.
[0083] At a first chip, a point {1, 1}, i.e., a point {circle
around (1)}, is designated on the phase domain by first real values
contained in the spreading codes of C.sub.4, 2 and C.sub.4, 3. At a
second chip, a point {-1, -1}, i.e., a point {circle around (2)},
is designated on the phase domain by second real values contained
in the spreading codes of C.sub.4, 2 and C.sub.4, 3. The points
{circle around (1)} and {circle around (2)} are symmetrical with
respect to a zero point as a center point on the phase domain.
[0084] At a third chip, a point {1, -1}, i.e., a point {circle
around (3)}, is designated on the phase domain by third real values
contained in the spreading codes of C.sub.4, 2 and C.sub.4, 3. At a
fourth chip, a point {-1, 1}, i.e., a point {circle around (4)}, is
designated on the phase domain by fourth real values contained in
the spreading codes of C.sub.4, 2 and C.sub.4, 3. The points
{circle around (3)} and {circle around (4)} are symmetrical with
respect to the zero point on the phase domain.
[0085] Where the Walsh rotator rotates the points at chips, the
points are rotated by a predetermined phase, respectively.
[0086] For example, where the Walsh rotator rotates the point
{circle around (1)} or {circle around (3)} at an odd chip, the
point {circle around (1)} or is rotated to a clockwise direction by
a phase of 45.degree.. Further, where the Walsh rotator rotates the
point {circle around (2)} or {circle around (4)} at an even chip,
the point {circle around (2)} or {circle around (4)} is rotated to
a counterclockwise direction by the phase of 45.degree.. After
rotating the points {circle around (1)} and {circle around (2)} or
the points {circle around (3)} and {circle around (4)} at the odd
and even chips as two consecutive chips, a phase difference between
the rotated points {circle around (1)}' and {circle around (2)}' or
the rotated points {circle around (3)}' and {circle around (4)}'
becomes 90.degree.. Where the phase difference between the rotated
points {circle around (1)}' and {circle around (2)}', or the
rotated points {circle around (3)}' and {circle around (4)}'
becomes 90.degree., a peak-to-average power ratio of a mobile
station can be reduced.
[0087] For another example, where the Walsh rotator rotates the
point {circle around (1)} or {circle around (3)} at an odd chip,
the point {circle around (1)} or {circle around (3)} is rotated to
the counterclockwise direction by the phase of 45.degree.. Further,
where the Walsh rotator rotates the point {circle around (2)} or
{circle around (4)} at an even chip, the point {circle around (2)}
or {circle around (4)} is rotated to the clockwise direction by the
phase of 45.degree..
[0088] After rotating the points {circle around (1)} and {circle
around (2)} or the points {circle around (3)} and {circle around
(4)} at the odd and even chips as two consecutive chips, a phase
difference between the rotated points {circle around (1)}'' and
{circle around (2)}'' or the rotated points {circle around (3)}''
and {circle around (4)}'' becomes 90.degree.. Where the phase
difference between the rotated points {circle around (1)}'' and
{circle around (2)}'' or the rotated points {circle around (3)}''
and {circle around (4)}'' becomes 90.degree., the peak-to-average
power ratio of the mobile station can be reduced.
[0089] Referring to FIG. 10, there is shown a first exemplary view
depicting an undesirable phase difference between rotated points on
a phase domain where a Walsh rotator rotates points at consecutive
chips.
[0090] First, assume that two channels are spread by the spreading
code of C.sub.4, 0={1, 1, 1, 1} and the spreading code of C.sub.4,
2={1, -1, 1, -1}, respectively.
[0091] At a first chip, a point {1, 1}, i.e., a point {circle
around (1)}, is designated on the phase domain by first real values
contained in the spreading codes of C.sub.4, 0 and C.sub.4, 2. At a
second chip, a point {1, -1}, i.e., a point {circle around (2)}, is
designated on the phase domain by second real values contained in
the spreading codes of C.sub.4, 0 and C.sub.4, 2. The points
{circle around (1)} and {circle around (2)} are symmetrical with
respect to the real axis on the phase domain.
[0092] At a third chip, a point {1, 1}, i.e., a point {circle
around (3)}, is designated on the phase domain by third real values
contained in the spreading codes of C.sub.4, 0 and C.sub.4, 2. At a
fourth chip, a point {1, -1}, i.e., a point {circle around (4)}, is
designated on the phase domain by fourth real values contained in
the spreading codes of C.sub.4, 0 and C.sub.4, 2. The points
{circle around (3)} and {circle around (4)} are symmetrical with
respect to the real axis on the phase domain.
[0093] Where the Walsh rotator rotates the points at chips, the
points are rotated by a predetermined phase, respectively.
[0094] For example, where the Walsh rotator rotates the point
{circle around (1)} or {circle around (3)} at an odd chip, the
point {circle around (1)} or {circle around (3)} is rotated to a
counterclockwise direction by a phase of 45.degree.. Further, where
the Walsh rotator rotates the point {circle around (2)} or {circle
around (4)} at an even chip, the point {circle around (2)} or
{circle around (4)} is rotated to a clockwise direction by the
phase of 45.degree.. After rotating the points {circle around (1)}
and {circle around (2)} or the points {circle around (3)} and
{circle around (4)} at the odd and even chips as two consecutive
chips, a phase difference between the rotated points {circle around
(1)}' and {circle around (2)}' or the rotated points {circle around
(3)}' and {circle around (4)}' becomes zero. Where the phase
difference between the rotated points {circle around (1)}' and
{circle around (2)}' or the rotated points {circle around (3)}' and
{circle around (4)}' does not become 90.degree., a peak-to-average
power ratio of a mobile station can not be reduced.
[0095] Referring to FIGS. 11 and 12, there are shown third
exemplary views illustrating a desirable phase difference between
rotated points on a phase domain where a Walsh rotator rotates
points at consecutive chips.
[0096] First, assume that data of 1 allocated to a first channel is
spread by a spreading code of C.sub.4, 1={1, 1, -1, -1}. Further,
assume that data of -1 allocated to a second channel is spread by a
spreading code of C.sub.4, 1={1, 1, -1, -1}. Furthermore, assume
that data of 1 allocated to a third channel is spread by a
spreading code of C.sub.4, 0={1, 1, 1, 1}.
[0097] In terms of the first channel, the spreader 130 shown in
FIG. 3 multiplies the data of 1 by the spreading code of C.sub.4,
1={1, 1, -1, -1}, thereby generating a code of {1, 1, -1, -1}.
Further, in terms of the second channel, the spreader 130
multiplies the data of -1 by the spreading code of C.sub.4, 1={1,
1, -1, -1}, thereby generating a code of {-1, -1, 1, 1}.
Furthermore, in terms of the third channel, the spreader 130
multiplies the data of 1 by the spreading code of C.sub.4, 0={1, 1,
1, 1}, thereby generating a code of {1, 1, 1, 1}.
[0098] Where the spreader 130 includes an adder 131 shown in FIG.
12, the adder 131 generates a code of {0, 0, 2, 2} by adding the
code of {-1, -1, 1, 1} to the code of {1, 1, 1, 1}.
TABLE-US-00001 TABLE 1 Chip 1 2 3 4 First Channel 1 1 -1 -1 Second
Channel -1 -1 1 1 Third Channel 1 1 1 1 Second channel + Third
channel 0 0 2 2
[0099] Table 1 represents the spreading codes allocated to three
channels and a sum of two channels depending upon chips. At a first
or second chip, a point {1, 0}, i.e., a point {circle around (1)}
or {circle around (2)}, is designated on the phase domain by first
or second real values contained in the code of {1, 1, -1, -1} and
the code of {0, 0, 2, 2}. At a third or fourth chip, a point {-1,
2}, i.e., a point {circle around (3)} or {circle around (4)}, is
designated on the phase domain by third or fourth real values
contained in the code of {1, 1, -1, -1} and the code of {0, 0, 2,
2}. The points {circle around (1)} and {circle around (2)} are
positioned on the same point as each other. Also, the points
{circle around (3)} and {circle around (4)} are positioned on the
same point as each other. Where the Walsh rotator rotates the
points at chips, the points are rotated by a predetermined phase,
respectively.
[0100] For example, where the Walsh rotator rotates the point
{circle around (1)} or {circle around (3)} at an odd chip, the
point {circle around (1)} or {circle around (3)} is rotated to a
clockwise direction by a phase of 45.degree.. Further, where the
Walsh rotator rotates the point {circle around (2)} or {circle
around (4)} at an even chip, the point {circle around (2)} or
{circle around (4)} is rotated to a counterclockwise direction by
the phase of 45.degree.. After rotating the points {circle around
(1)} and {circle around (2)} or the points {circle around (3)} and
{circle around (4)} at the odd and even chips as two consecutive
chips, a phase difference between the rotated points {circle around
(1)}' and {circle around (2)}' or the rotated points {circle around
(3)}' and {circle around (4)}' becomes 90.degree.. Where the phase
difference between the rotated points {circle around (1)}' and
{circle around (2)}' or the rotated points {circle around (3)}' and
{circle around (4)}' becomes 90.degree., a peak-to-average power
ratio of a mobile station can be reduced.
[0101] Referring to FIGS. 13 and 14, there are shown second
exemplary views illustrating an undesirable phase difference
between rotated points on a phase domain where a Walsh rotator
rotates points at consecutive chips.
[0102] First, assume that data of 1 allocated to a first channel is
spread by a spreading code of C.sub.4, 1={1, 1, -1, -1}. Further,
assume that data of -1 allocated to a second channel is spread by a
spreading code of C.sub.4, 2={1, -1, 1, -1}. Furthermore, assume
that data of 1 allocated to a third channel is spread by a
spreading code of C.sub.4, 0={1, 1, 1, 1}.
[0103] In terms of the first channel, the spreader 130 shown in
FIG. 2 multiplies the data of 1 with the spreading code of C.sub.4,
1={1, 1, -1, -1}, thereby generating a code of {1, 1, -1, -1}.
Further, in terms of the second channel, the spreader 130
multiplies the data of -1 by the spreading code of C.sub.4, 2={1,
-1, 1, -1}, thereby generating a code of {-1, 1, -1, 1}.
Furthermore, in terms of the third channel, the spreader 130
multiplies the data of 1 by the spreading code of C.sub.4, 0={1, 1,
1, 1}, thereby generating a code of {1, 1, 1, 1}.
[0104] Where the spreader 130 includes an adder 133 shown in FIG.
14, the adder 133 generates a code of {0, 2, 0, 2} by adding the
code of {-1, 1, -1, 1} to the code of {1, 1, 1, 1}.
TABLE-US-00002 TABLE 2 Chip 1 2 3 4 First Channel 1 1 -1 -1 Second
Channel -1 1 -1 1 Third Channel 1 1 1 1 Second channel + third
channel 0 2 0 2
[0105] Table 2 represents the spreading codes allocated to three
channels and a sum of two channels depending upon chips. At a first
chip, a point {1, 0}, i.e., a point {circle around (1)}, is
designated on the phase domain by first real values contained in
the code of {1, 1, -1, -1} and the code of {0, 2, 0, 2}. At a
second chip, a point {1, 2}, i.e., a point {circle around (2)}, is
designated on the phase domain by second real values contained in
the code of {1, 1, -1, -1} and the code of {0, 2, 0, 2}. At a third
chip, a point {-1, 0}, i.e., a point {circle around (3)}, is
designated on the phase domain by third real values contained in
the code of {1, 1, -1, -1} and the code of {0, 2, 0, 2}. At a
fourth chip, a point {-1, 2}, i.e., a point {circle around (4)}, is
designated on the phase domain by third real values contained in
the code of {1, 1, -1, -1} and the code of {0, 2, 0, 2}.
[0106] The points {circle around (1)} and {circle around (2)} or
the points {circle around (3)} and {circle around (4)} are
positioned on different points from each other. Where the Walsh
rotator rotates the points at chips, the points are rotated by a
predetermined phase, respectively.
[0107] For example, where the Walsh rotator rotates the point
{circle around (1)} or {circle around (3)} at an odd chip, the
point {circle around (1)} or {circle around (3)} is rotated to a
clockwise direction by a phase of 45.degree.. Further, where the
Walsh rotator rotates the point {circle around (2)} or {circle
around (4)} at an even chip, the point {circle around (2)} or
{circle around (4)} is rotated to a counterclockwise direction by
the phase of 45.degree.. After rotating the points {circle around
(3)} and {circle around (4)} at the odd and even chips as two
consecutive chips, a phase difference between the rotated points
{circle around (3)}' and {circle around (4)}' does not become
90.degree.. Where the phase difference between the rotated points
{circle around (3)}' and {circle around (4)}' does not become
90.degree., a peak-to-average power ratio of a mobile station can
increase.
[0108] Further, after rotating the points {circle around (1)} and
{circle around (2)} at the odd and even chips as two consecutive
chips, a phase difference between the rotated points {circle around
(1)}' and {circle around (2)}' does not become 90.degree.. Where
the phase difference between the rotated points {circle around
(1)}' and {circle around (2)}' does not become 90.degree., the
peak-to-average power ratio of a mobile station can increase.
[0109] Referring to FIG. 15, there is shown an exemplary graphical
diagram describing the probability of peak to average power.
[0110] When a mobile station employs two channels and spreading
codes of C.sub.4, 0={1, 1, 1, 1} and C.sub.4, 1={1, 1, -1, -1}
allocated to the two channels, a curve G1 is shown in the graphical
diagram. At this time, the probability of the peak power exceeding
the average power by 2.5 dB is approximately 1%.
[0111] Further, when a mobile station employs two channels and
spreading codes of C.sub.4, 0={1, 1, 1, 1} and C.sub.4, 2={1, -1,
1, -1} allocated to the two channels, a curve G2 is shown in the
graphical diagram.
[0112] At this time, the probability of the peak power exceeding
the average power by 2.5 dB is approximately 7%.
[0113] Referring to FIG. 16, there is shown a flowchart depicting a
method for modulating a data message in a mobile station in
accordance with the present invention.
[0114] As shown, at step S1302, an encoder receives a data message
to be transmitted to a base station.
[0115] At step S1304, the encoder encodes the data message having
one or more data parts and generates a control part.
[0116] At step S1306, the encoder evaluates an SF related to the
one or more data parts to send the SF from an encoder to a CPU.
[0117] At step S1308, the CPU produces information necessary to
generate spreading codes to be allocated to channels.
[0118] At step S1310, a code generator generates the spreading
codes.
[0119] At step S1312, a spreader spreads the control part and the
one or more data parts by the spreading codes.
[0120] At step S1314, a scrambler scrambles the control part and
the one or more data parts spread and a complex-valued scrambling
code, to thereby generate a channel-modulated signal having a
plurality of pairs of in-phase (I) and quadrature-phase (Q) data in
the mobile station.
[0121] Referring to FIGS. 17 to 19, there are flowcharts
illustrative of a procedure for producing information necessary to
generate spreading codes to be allocated to channels.
[0122] As shown, at step S1402, the CPU receives the SF related to
the one or more data parts from the encoder.
[0123] At step S1404, the CPU determines a type of an event.
[0124] At step S1408, if the event is a case where a mobile station
uses two channels, the CPU produces an SF of 256 and a code number
of 0 related to the control part.
[0125] At step S1410, the CPU produces a code number of SF/4
related to the one data part where SF=2.sup.N and N=2 to 8.
[0126] At step S1412, the CPU sends the code numbers and the SFs
related to the data and control parts to the code generator.
[0127] On the other hand, at step S1414, if the event is a case
where multiple mobile stations share a common complex-valued
scrambling code, the CPU produces a signature S.
[0128] At step S1416, the CPU produces the SF of 256 and a code
number of 16(S-1)+15 related to the control part where S=1 to
16.
[0129] At step S1418, the CPU produces a code number of SF(S-1)/16
related to the one data part where SF=2.sup.N, N=2 to 8 and S=1 to
16.
[0130] At step S1420, the CPU sends the code numbers and the SFs
related to the data and control parts to the code generator.
[0131] On the other hand, at step S1424, if the event is a case
where a mobile station uses multiple channels, the CPU produces a
code number of 0 and the SF of 256 related to the control part
allocated to the control channel.
[0132] At step S1502, the CPU determines the number of data
channels.
[0133] At step S1504, if the number of data channels is two data
channels, the CPU produces a code number of 1 and an SF of 4
related to a first data part allocated to a first data channel
coupled to an I branch.
[0134] At step S1506, the CPU produces a code number of 1 and the
SF of 4 related to a second data part allocated to a second data
channel.
[0135] On the other hand, at step S1508, if the number of data
channels is three data channels, the CPU produces the code number
of 1 and the SF of 4 related to the first data part allocated to
the first data channel.
[0136] At step S1510, the CPU produces the code number of 1 and the
SF of 4 related to the second data part allocated to the second
data channel.
[0137] At step S1512, the CPU produces a code number of 3 and the
SF of 4 related to the third data part allocated to the third data
channel.
[0138] On the other hand, at step S1514, if the number of data
channels is four data channels, the CPU produces the code number of
1 and the SF of 4 related to the first data part allocated to the
first data channel.
[0139] At step S1516, the CPU produces the code number of 1 and the
SF of 4 related to the second data part allocated to the second
data channel.
[0140] At step S1518, the CPU produces the code number of 3 and the
SF of 4 related to the third data part allocated to the third data
channel.
At step S1520, the CPU produces the code number of 3 and the SF of
4 related to a fourth data part allocated to a fourth data
channel.
[0141] On the other hand, at step S1522, if the number of data
channels is five data channels, the CPU produces the code number of
1 and the SF of 4 related to the first data part allocated to the
first data channel.
[0142] At step S1524, the CPU produces the code number of 1 and the
SF of 4 related to the second data part allocated to the second
data channel.
At step S1526, the CPU produces the code number of 3 and the SF of
4 related to the third data part allocated to the third data
channel.
[0143] At step S1528, the CPU produces the code number of 3 and the
SF of 4 related to the fourth data part allocated to the fourth
data channel.
[0144] At step S1530, the CPU produces the code number of 2 and the
SF of 4 related to a fifth data part allocated to a fifth data
channel.
[0145] On the other hand, at step S1532, if the number of data
channels is six data channels, the CPU produces the code number of
1 and the SF of 4 related to the first data part allocated to the
first data channel.
At step S1534, the CPU produces the code number of 1 and the SF of
4 related to the second data part allocated to the second data
channel.
[0146] At step S1536, the CPU produces the code number of 3 and the
SF of 4 related to the third data part allocated to the third data
channel.
[0147] At step S1538, the CPU produces the code number of 3 and the
SF of 4 related to the fourth data part allocated to the fourth
data channel.
[0148] At step S1540, the CPU produces the code number of 2 and the
SF of 4 related to the fifth data part allocated to the fifth data
channel.
[0149] At step S1542, the CPU produces the code number of 2 and the
SF of 4 related to a sixth data part allocated to a sixth data
channel.
[0150] At step S1521, the CPU transmits the code numbers and the
SFs related to the data and control parts to the code
generator.
[0151] Referring to FIG. 20, there is shown a flowchart showing a
procedure of generating the spreading codes.
[0152] As shown, at step S1702, registers receive the code numbers
and the SFs from the CPU.
[0153] At step S1704, registers store the code numbers and the
SFs.
[0154] At step S1706, logical operators carry out logical
operations in response to an 8-bit count value, thereby generating
the spreading codes.
[0155] At step S1708, multiplexers select the spreading codes in
response to the SFs as select signals.
[0156] Referring to FIGS. 21 and 22, there are shown flowcharts
describing a procedure of carrying out the logical operations in
response to the 8-bit count value, thereby generating the spreading
codes.
[0157] As shown, at step S1802, each register receives a code
number of I.sub.7I.sub.6I.sub.5I.sub.4I.sub.3I.sub.2I.sub.1I.sub.0
and a predetermined SF.
[0158] At step S1804, each register receives an 8-bit count value
of B.sub.7B.sub.6B.sub.5B.sub.4B.sub.3B.sub.2B.sub.1B.sub.0 from an
8-bit counter.
[0159] At step S1806, a type of the predetermined SF is
determined.
[0160] At step S1808, if the predetermined SF is SF.sub.256, each
logical operator carries out a logical operation of
B.sub.7I.sub.0.sym.B.sub.6I.sub.1.sym.B.sub.5I.sub.2.sym.B.sub.4I.sub.3.s-
ym.B.sub.3I.sub.4.sym.B.sub.2I.sub.5.sym.B.sub.1I.sub.6.sym.B.sub.0I.sub.7-
.
[0161] At step S1810, if the predetermined SF is SF.sub.128, each
logical operator carries out a logical operation of
B.sub.6I.sub.0.sym.B.sub.5I.sub.1.sym.B.sub.4I.sub.2.sym.B.sub.3I.sub.3.s-
ym.B.sub.2I.sub.4.sym.B.sub.1I.sub.5.sym.B.sub.0I.sub.6.
[0162] At step S1812, if the predetermined SF is SF.sub.64, each
logical operator carries out a logical operation of
B.sub.5I.sub.0.sym.B.sub.4I.sub.1.sym.B.sub.3I.sub.2.sym.B.sub.2I.sub.3.s-
ym.B.sub.1I.sub.4.sym.B.sub.0I.sub.5.
[0163] At step S1814, if the predetermined SF is SF.sub.32, each
logical operator carries out a logical operation of
B.sub.4I.sub.0.sym.B.sub.3I.sub.1.sym.B.sub.2I.sub.2.sym.B.sub.1I.sub.3.s-
ym.B.sub.0I.sub.4.
[0164] At step S1816, if the predetermined SF is SF.sub.16, each
logical operator carries out a logical operation of
B.sub.3I.sub.0.sym.B.sub.2I.sub.1.sym.B.sub.1I.sub.2.sym.B.sub.0I.sub.3.
[0165] At step S1818, if the predetermined SF is SF.sub.8, each
logical operator carries out a logical operation of
B.sub.2I.sub.0.sym.B.sub.1I.sub.1.sym.B.sub.0I.sub.2.
[0166] At step S1820, if the predetermined SF is SF.sub.4, each
logical operator carries out a logical operation of
B.sub.1I.sub.0.sym.B.sub.0I.sub.1.
[0167] At step S1822, each multiplexer generates a spreading code
in response to the SF.
[0168] Although the preferred embodiments of the 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 disclosed in the accompanying
claims.
* * * * *