JP2000244970A - Mobile communication method using cdma multiplexing technology and radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably realize communication by allowing a mobile terminal to reduce disturbance on call control information or a signal channel from a perch channel. SOLUTION: In the CDMA communication method where communication is conducted through a signal channel through which user data are sent and through a parch channel through which a spread code used for demodulating the user data is transmitted, the signal channel has a call control channel F that is in time division multiplex processing and the call control channel F and parts C, D of the perch channel losing orthogonality to the call control channel are allocated without temporal overlapping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication method using a CDMA (code division multiple access) technique and a radio base station used for the same, and more particularly, to a radio base station used for the mobile communication method.
The present invention relates to a mobile communication method and a radio base station using a CDMA multiplexing technique capable of preventing a call control signal from being disturbed by interference inevitably generated between signals multiplexed by a DMA system.

[0002]

2. Description of the Related Art In the CDMA system, a transmitting side modulates each radio channel with a unique spreading code and then multiplexes the data, and the receiving side performs a decoding operation called despreading using a code specific to each radio channel. This is a method of multiplexing / demultiplexing each channel. For this purpose, the receiving side must despread the same spreading code as the transmitting side with the same phase. In general, a mobile communication system uses a different spreading code for each call connection, so it is necessary to notify the receiving side of the spreading code to be used in advance.

Therefore, the CDMA mobile communication system sets a broadcast channel called a perch channel in addition to a channel for transmitting user data for communication, and transmits code information required for despreading using this channel. ing.
This perch channel is code-modulated with spreading codes orthogonal to each other to separate the channel from other channels (control channel, signal channel, etc.). Since the spreading code for channel separation is a spreading code unique to the system, it is a spreading code known to the mobile terminal.
The perch channel is a broadcast channel for transmitting common control information to a plurality of mobile terminals.

On the other hand, in a CDMA system, it is necessary for a mobile terminal to discriminate each base station. Each base station spreads and transmits a perch channel with a spreading code unique to each base station. That is, the perch channel is double-spread by a spreading code for channel separation and a spreading code for base station discrimination. Since the spreading code for base station discrimination is a spreading code unknown to the mobile terminal, unlike the spreading code for channel separation, the mobile terminal determines a spreading code for base station classification from a plurality of candidates. You must try and find out if they match one by one.

FIG. 9 is a diagram for explaining a perch channel signal system according to the above-mentioned prior art, which will be described below. In FIG. 9, A is one of the perch channels.
Slot B is one slot of the signal channel.

[0006] The perch channel transmits a code for despreading used by the mobile terminal, and the signal channel transmits user signals such as speech signals and data signals. Each slot A of the perch channel is double-spread and code-modulated by a short code C1 unique to the system and common to each base station in the system and a long code D1 unique to a specific base station.

Each of the perch channels transmitted simultaneously by the base station and the original signal channel group (a plurality of signal channels exist according to the number of mobile terminals in communication) is used to avoid mutual interference. Spreading is performed using spreading codes orthogonal to each other. On the other hand, a code D1 unique to a specific base station
In this case, it is easier to configure the system by making the signal common to all signal channels emitted from a specific base station. For this reason, each slot B of other signal channels other than the perch channel emitted from the same base station,
Double spreading is performed using another short code Cn orthogonal to the system-specific short code C1 used for the perch channel, and a long code D1 specific to the same specific base station as the perch channel. By using Cn which is orthogonal to C1 in code, it is possible to ensure orthogonality between the perch channel and the signal channel.

However, in the above-described example, since the code D1 unique to the base station is not known to the mobile terminal in advance, the mobile terminal tries all codes that can be considered in principle in order,
You must search for the correct code. This method requires a lot of time to search for a code when there are a large number of codes or when the code length is extremely long.

Therefore, a method has been considered in which codes assigned uniquely to the base station are classified into some groups in advance, and this classification information is transmitted in advance. In this case, the mobile terminal first
There is known a method of detecting a group to which a necessary code belongs, narrowing a search target, and searching for a code in the group to reduce a search time.

Further, in order to perform despreading using a long code D1 unique to the base station, it is necessary to know the time (code phase) at which despreading is started by the code. However, in the example shown in FIG. 9, the start time cannot be known before the identity of the code D1 is known, and this must be solved.

FIG. 10 is a diagram for explaining a perch channel signal system according to another prior art which can solve the above-mentioned problem. This will be described below.

The example shown in FIG. 10 uses the first and second two types of perch channels as perch channels. Each slot of the first perch channel is defined by a short code C1 that is system-specific and common to each base station in the system and a long code D1 that is specific to a specific base station, as described with reference to FIG. An area A1 is code-modulated by being heavily spread, and an area C is spread by a different spreading code. This area C is
A long spreading code D1 and a system-specific short spreading code C1
, And the short spreading code O2
Has been spread using.

The spreading code O2 is used to clarify the transmission phase of the perch channel, and the mobile terminal can receive the region C and synchronize the slot of the perch channel. That is, the mobile terminal can know from which time the long spreading code D1 was started. As the spreading code O2, a code predetermined by the system can be used similarly to the spreading code C1, but a special code with a small correlation is used so that the mobile terminal can easily establish slot synchronization. Is used.

The second perch channel includes the first perch channel.
A region D is set at a time position synchronized with the region C of the perch channel. This area D is spread by a short spreading code O3 indicating to which classification (group) the long spreading code D1 unique to the base station belongs. O2 and O3 are orthogonal in terms of code, and can be separated even if they overlap in time. A section from a certain area D to the next area D, that is, a portion synchronized with the area A1 of the first perch channel is empty.

Conventional techniques relating to the above-described mobile communication method using the CDMA multiplexing technique include, for example, Kenichi Higuchi, Mamoru Sawahashi, and Fumiyuki Adachi “High-speed using long code mask in asynchronous cellular between DS-CDMA base stations. Cell Search Method ”IEICE TECHNICAL REPORT OF
IEICE DSP96-116, SAT96-111, RCS96-122 (1997-01)
And the like are known.

[0016]

The prior art shown in FIG. 10 described above uses the first and second perch channel regions C
And the long spreading code D1 is not used for spreading in the area D, and the short spreading codes O2 and O3 are
And codes that are orthogonal to are not necessarily used. Therefore, the areas C and D are not orthogonal to the communication channels other than the perch channel. For this reason, in the above-described related art, there is a possibility that signals in the regions C and D of the first and second perch channels interfere with the communication channel and cause interference similar to white noise.

The above-described interference causes partial noise to be mixed in the signal on the original signal channel. However, in general, sufficient interleaving in the signal channel does not cause partial error. It is not a big problem because it is averaged.

However, in a general signal channel, call control information for ring trip, handover, call termination control and the like are multiplexed in addition to the original signal information. If it overlaps with the area of the call control information in time, it will seriously interfere with the call control information.

FIG. 11 is a diagram for explaining that areas C and D interfere with call control information on a signal channel.
Hereinafter, this will be described.

In FIG. 11, the first and second perch channels are configured in the same manner as described with reference to FIG. The signal channel for the original user signal transmits, in addition to the original signal information transmitted in the area E, the call control information used for ring trip, handover, call termination control, and the like in the area F. Region F is provided. Here, the regions F and E are spread by the spreading code Cn and the spreading code D1 as described above. Since the required bit rate of the call control information is lower than that of the original signal information, as shown in FIG. 11, the area F where the signal information is transmitted is time-division multiplexed as an area F having a relatively short time width. . The length of one slot formed by the regions E and F of the signal channel is the same as the length of one slot formed by the regions A and C of the first perch channel.

FIG. 11 shows, for the sake of convenience, that the time positions of the first and second perch channel regions C and D and the signal channel region F completely coincide with each other. However, since a different slot offset is set for each signal channel of each mobile terminal, the area F
May partially overlap the regions C and D.

For this reason, the prior art described with reference to FIG. 10 uses the region C of the perch channel as shown in FIG.
Alternatively, when the area D and the area F for transmitting the call control information overlap, interference with the call control information occurs. In general,
User information such as voice and data will not cause fatal service degradation even if a transient error occurs,
On the other hand, there is an important problem that an error in the call control information leads to instability of the call connection and a significant decrease in service. In particular, since the time width of the area F in which the call control information is transmitted is shorter than that of the area E or A1, the entire area may overlap the area C or D. In this case, only the area F is interleaved. Even so, no improvement in error can be expected.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a region C and a long region C used to clarify the transmission phase of the perch channel in the first and second perch channels. It is an object of the present invention to provide a mobile communication method and a radio base station using a CDMA multiplexing technique capable of preventing an area D indicating a group of spreading codes D1 from interfering with call control information on a signal channel. is there.

[0024]

According to the present invention, the above object is achieved by a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of the call control information. A mobile communication method for performing communication between a radio base station and a mobile terminal, wherein the perch channel and the call control channel are set at an error rate when the mobile terminal receives the call control channel; This is achieved by arranging and transmitting on the time axis as follows.

Further, the object is to provide the call control channel and a part provided in a part of the perch channel when the perch channel and the call control channel are arranged on a time axis. This is achieved by arranging the call control channel and the portion that is not code orthogonal so that the error rate when receiving the call control channel is equal to or less than a threshold.

The above object is achieved by interleaving the call control channels when arranging the perch channels and the call control channels.

[0027] The above object is also achieved by a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of the call control information. In a mobile communication method for performing communication between mobile stations, this is achieved by arranging and transmitting the perch channel and the call control channel on a time axis so that the mobile terminal can demodulate the call control channel.

[0028] Further, the object is that a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of the call control information allow a radio base station and a mobile terminal to communicate with each other. In a mobile communication method for performing communication between the mobile terminals, the mobile terminal achieves this by controlling the power of the call control channel and transmitting the power so that the call control channel can be demodulated.

The object is to use a radio base station for spreading a call control information with a first spreading code to generate a call control channel and for despread demodulation of the call control information. A second channel generator for generating a perch channel for transmitting a first spreading code, a call control channel generated by the first channel generator, and a pause generated by the second channel generator. This is achieved by providing a channel multiplexing unit that arranges the call control channel so that it can be demodulated when multiplexing with the tree channel.

[0030] Also, the object is that the multiplexing unit demodulates the call control channel and a portion of the perch channel that is not code orthogonal to the call control channel when the call control channel is received. This is achieved by arranging them on the time axis as much as possible.

Further, the above object is achieved by the multiplexing section multiplexing the perch channel and the interleaved call control channel.

Further, the above object is achieved by further comprising a control unit for controlling the transmission power of the call control channel, wherein the control unit adjusts the power so that the call control channel can be demodulated.

[0033] Further, the object is to provide a CDMA multiplex system for performing communication between a radio base station and a mobile terminal by using a signal channel for transmitting user data and a perch channel for transmitting a spreading code used for demodulating the user data. In the mobile communication method using the multiplexing technique, the signal channel has a time-division multiplexed call control channel, and the spread of the call control channel and another channel provided in a part of the perch channel. This is achieved by arranging the portion where the orthogonality of the code is lost without overlapping in time.

[0034] The object of the present invention is to provide a CDMA multiplex system for performing communication between a radio base station and a mobile terminal by using a signal channel for transmitting user data and a perch channel for transmitting a spreading code used for demodulating the user data. In the mobile communication method using the multiplexing technique, the signal channel has a time division multiplexed call control channel, and the signal of the call control channel and user data are time division multiplexed and interleaved. It is achieved by doing.

The object of the present invention is to allow the base station to set the transmission power of the signal channel to Pu, the transmission power of the perch channel to Pp, and the signal-to-interference power ratio required for receiving the signal channel without error. When SIRr and the spreading gain of the signal channel are Gd = 10 log (spreading rate / bit rate of the signal channel), the transmission power of the perch channel and the signal channel is controlled so as to satisfy the condition of Pu ≧ Pp + SIRr-Gd. This is achieved by:

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a mobile communication method and a radio base station using a CDMA multiplexing technique according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a mobile communication system to which the present invention is applied. First, this will be described. In FIG. 1, reference numeral 100 denotes a public network (PST).
N) and 101 are exchanges (SW), 102 is a base station control station, 103 and 113 are radio base stations, and 104 and 114 are mobile terminals.

A mobile communication system to which the present invention shown in FIG. 1 is applied includes a public network 100, an exchange 101, a base station control station 102 for controlling a base station, and a radio base station 10
3 and 113 and the mobile terminals 104 and 114. FIG. 1 also shows a first perch channel 105, a second perch channel 106, and a signal channel 107 having an appropriate slot offset, which will be described later.
An interleaved signal 117 of the signal channel is also shown. By arranging the signaling channels in this way, it is possible to prevent call control information errors in the signaling channels.

FIG. 2 is a block diagram showing the configuration of a radio base station according to the first embodiment of the present invention, FIG. 4 is a block diagram showing the configuration of a mobile terminal according to the first embodiment of the present invention, and FIG.
FIG. 3 is a diagram illustrating a configuration example of a perch channel and a signal channel according to the first embodiment of the present invention. 2 and 4, reference numerals 200, 202, and 212 denote multiplexing units, 201 denotes an amplifier, 203 denotes a first perch channel generation unit, and 204
Is a second perch channel creation unit, 205 is a signal channel creation unit, 206 is a power control unit, 208 is a control unit, 21
0 and 211 are spreading code generators, 400 is a demultiplexer, 40
1 to 404, 406, and 407 are despreading units, 405 is a control unit (CPU), and 408 to 410 are error correction units.

The radio base station 103 according to the first embodiment of the present invention, as shown in FIG.
Multiplexing section 200 for multiplexing and transmitting the second perch channel and the signal channel, first perch channel creating section 2
03, a second perch channel creating section 204, a signal channel creating section 205, a power control section 206 for controlling the power of the signal channel, and an SIR estimating section (not shown) for estimating the SIR of a received signal used by the power control section 207.

The first perch channel creating section 203 spreads broadcast information, which is control information common to a plurality of mobile terminals, with a long spreading code D1 unique to the base station and a short spreading code C1 unique to the system. This diffusion region is the first region shown in FIG.
This is the area A1 of the perch channel 105. Region C is
Spreading is performed with a spreading code O2 indicating the start position of the spreading code D1. It should be noted that the area C is all 1 data.
Here, the spreading codes D1, C1, and O2 are created by the spreading code creating unit 210 and set in the spreader. The multiplexing unit 202 multiplexes the area A1 and the area C after the diffusion.

The second perch channel creating section 204 performs spreading by a spreading code O3 indicating a group to which the spreading code D1 belongs, and generates a region D. The area D is all 1
Data.

The signal channel creation section 205 multiplexes communication information (area E) such as voice and data and call control information (area F) such as a ring trip, and the multiplexed area F , E, and a spreading code generator 211 for generating a spreading code D1. Further, the control unit 208 controls the spread code generation units 210 and 211, and instructs, for example, a slot offset and the like. That is, control section 208 sets a slot offset in the spread code generation section so that no serious error occurs in the call control information. The spreading code creation unit 211
A spreading code is generated based on the slot offset specified by the control unit 208.

The mobile terminal 1 according to the first embodiment of the present invention
4, a demultiplexing unit 400 for demultiplexing the received signal, a despreading unit 401 for despreading the second perch channel and searching for a spreading code O3, and a first perch channel A despreading unit 402 for despreading the area C and searching for the spreading code O2, a despreading unit 403 for despreading the area A1 of the first perch channel with the spreading code C1, and a despreading unit 403 for despreading with the spreading code C1. A despreading unit 406 for despreading the spread area based on an instruction from the control unit 405 and searching for a long spreading code D1, a despreading unit 404 for spreading a signal channel with a short spreading code Cn, and a despreading unit In 404, the signal channel spread with the spreading code Cn is added to the long spreading code D obtained from the first perch channel.
1, an error correcting section 408 for correcting errors in the despread and demodulated broadcast information, an error correcting section 409 for correcting errors in the despread and demodulated communication information such as voice and data, and And an error correction unit 410 that corrects the spread-demodulated call control information.

Next, the receiving operation of the mobile terminal 104 configured as described above will be described.

First, demultiplexing section 400 separates the received signal into a first perch channel, a second perch channel, and a signal channel. The despreading unit 401 generates the spreading code D1
Detects the spreading code O3 indicating the group to which the
02 detects the spreading code O2 by despreading the area C of the first perch channel. When these are detected, the control unit 405 can grasp the group to which the long spreading code belongs and the starting phase.
6 to search for a long spreading code used by the radio base station 103 for spreading the first perch channel. The control unit 405 controls the long spreading code D found by this search.
1 is set in the despreading unit 407. As a result, voice data and call control information can be despread and demodulated. These demodulated data and information are output via error correction units 408 to 410. The error correction units 408 to 410
May not be provided.

The perch channel and the signal channel in the first embodiment of the present invention are configured as shown in FIG. The first embodiment of the present invention clarifies the channel configuration to clarify the transmission phase of the perch channel in the first and second perch channels that may cause interference to the original signal channel. The outline is that the area C used for the communication and the area D indicating the group of the long spreading codes D1 are arranged so as not to coincide in time with the area F in which the call control information time-division multiplexed to the signal channel is transmitted. I have.

That is, as shown in FIG.
The start time of the region C of the perch channel of T0, the region C
Is completed, the time at which the area A1 is started is T1, the time at which the area A1 is completed and the next area C is started is T2, the start time of the signal channel area F is T3, the area F is completed, and the area E is started. When the time to be performed is T4, T3 ≧ T1 (1) T4 ≦ T2 (2) The slot offset is performed on the slot of the signal channel so as to satisfy the following condition.

As described above, the control unit 208 of the radio base station 103 performs the slot offset for the signal channel slot so as to satisfy the conditions shown in Expressions (1) and (2), thereby obtaining the signal channel. The area F in which the call control information is transmitted is the area C or the area D of the perch channel.
This can prevent the call control information from being disturbed by the signal of the perch channel.

Although the above-mentioned formulas do not completely match the areas, the areas may overlap if they are a little. The degree of overlap in this case is such that an error in the call control information is allowed. Note that if an error correction coding unit (not shown) is provided in the radio base station and error correction is performed on the call control information, it is possible to allow more overlapping of the areas. When error correction is performed at the wireless base station 103 in this way, by providing the mobile terminal 104 with the error correction unit 410, it is possible to correct errors in call control information due to overlapping areas.

FIG. 3 is a block diagram showing a configuration of a radio base station according to the second embodiment of the present invention. FIG. 5 is a block diagram showing a configuration of a mobile terminal according to the second embodiment of the present invention.
FIG. 8 is a diagram illustrating a configuration example of a perch channel and a signal channel according to the second embodiment of the present invention, and FIG. 8 is a diagram illustrating a state of interleaving. In FIG. 3 and FIG.
0 is an interleaving unit, 500 is a de-interleaving unit, and other symbols are the same as those in FIGS.

In the channel according to the second embodiment of the present invention, as shown in FIG. 7, the first and second perch channels have the same configuration as that described with reference to FIG. The signal channel in the second embodiment of the present invention is configured such that each slot G is time-division multiplexed with user information such as voice and data and call control information and then interleaved. .

The radio base station 113 according to the second embodiment of the present invention is configured as shown in FIG. The main difference between this radio base station and FIG.
5 in that an interleaving section 320 is provided. Interleaving section 320 receives the input call control information and voice /
Perform the operation of rearranging the order of data and the like. That is, as will be described later in detail, as shown in FIG. 8, the call control information arranged in a temporally sparse manner is arranged sparsely in a temporal manner. It should be noted that the second embodiment is different from the first embodiment in that the control unit 2
08 increases the degree of freedom in setting the slot offset.

The mobile terminal 114 according to the second embodiment of the present invention is configured as shown in FIG. The main difference between this mobile terminal and FIG. 4 is that the deinterleaving unit 50
0 is provided. The deinterleaving section 500 has a function of deinterleaving a signal channel interleaved by the radio base station 113 and reducing errors in call control information caused by interference of a perch channel. According to the second embodiment of the present invention, by performing interleaving, the area F of the call control information does not completely match the area C or the area D of the perch channel, but the amount is small. Means that the areas partially match.
Although an error occurs in the partially matched portion, error correction by the error correction units 409 and 410 makes it possible to reduce errors in call control information.

FIG. 8 shows that interference caused by a non-code orthogonal area C is reduced by temporally spreading the call control information by interleaving. FIG.
In the example shown in (1), since there are three interleaved regions F overlapping the region C, an error occurs in this portion, but a portion overlapping the region A1 having an orthogonal relationship can be transmitted without errors. .

As already described as a problem of the prior art, in the channel configuration shown in FIG. 11, the call control information transmitted in the area F in the signal channel is compared with the original user information transmitted in the signal channel. Since the amount of information is small, the burst width when time-division multiplexing is performed becomes short.
Therefore, as described with reference to FIG. 11, the area F in which the call control information is transmitted is a portion that causes interference with the signal channel indicated by the first and second perch channel areas C or D. Will cause an error in the call control because it may be completely covered by the call.

The channel configuration used in the second embodiment of the present invention shown in FIG. 7 is such that each slot G in a signal channel is time-division multiplexed with user information such as voice and data and call control information and then interleaved. After receiving the data in the area G, the receiving side separates the user signal and the call control signal by a deinterleave operation, and can extract a predetermined call control signal. Since the call control signals interleaved and distributed in the area G are widely distributed in time, the probability of occurrence of an error can be greatly reduced like the user signals.

According to the above-described first and second embodiments of the present invention, call control information causes interference due to inevitable interference between signals multiplexed by the CDMA system emitted from the base station. This can prevent the call connection control from becoming unstable.

As described above, the user information such as voice and data transmitted on the signal channel does not cause a fatal decrease in service even if a transient error occurs. However, the bit rate of the user information is several kb.
In the case of multimedia data of several hundred kbit / s, not audio information of about it / s, the ratio with respect to the spreading rate (chip rate) becomes small, so that the so-called spreading gain decreases and interference with the signal channel occurs. Poor immunity to interference.

Therefore, in the first and second embodiments of the present invention having the channel configuration described with reference to FIGS. 6 and 7, the section of the perch channel area C or area D corresponds to the user data on the signal channel. Interference becomes remarkable, and communication becomes difficult. In order to solve such a problem, it is necessary to prevent the transmission power of the signal channel from decreasing too much with respect to the transmission power of the perch channel.

Therefore, the radio base station according to the first and second embodiments of the present invention includes a power control section 206 as shown in FIGS.
The power of the signal channel is controlled by the following method by controlling the perch channel channel and the amplifier 201 that amplifies the signal channel. That is, the power control unit 206 needs to add the value of the power of the region C and the region D of the perch channel to Pp, to the transmission power of the signal channel transmitted from the base station to Pu, and to receive the signal channel without error. Is SIRr, and the spreading gain of the signal channel is Gd = 10 log (spreading rate /
(Signal bit rate), the transmission power of the perch channel and the signal channel is controlled so as to satisfy the condition of Pu ≧ Pp + SIRr−Gd (3). Thus, the minimum power value of the signal channel is changed according to the bit rate of the user data transmitted on the signal channel.

[0062]

As described above, according to the present invention, it is possible to reduce interference from a perch channel to call control information or a signal channel on the mobile terminal side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a mobile communication system to which the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a wireless base station according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a wireless base station according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a mobile terminal according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a mobile terminal according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration example of a perch channel and a signal channel of the mobile communication method using the CDMA multiplexing technology according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration example of a perch channel and a signal channel of a mobile communication method using a CDMA multiplexing technique according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a state of interleaving.

FIG. 9 is a diagram illustrating a perch channel signal system according to the related art.

FIG. 10 is a diagram illustrating a perch channel signal system according to the related art.

FIG. 11 is a diagram illustrating that regions C and D on a perch channel interfere with call control information on a signal channel.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Public network (PSTN) 101 Switching center (SW) 102 Base station control station 103, 113 Radio base station 104, 114 Mobile terminal 200, 202, 212 Multiplexing unit 201 Amplifier 203 First perch channel creating unit 204 Second stopping Tree channel creation unit 205 Signal channel creation unit 206 Power control unit 208 Control unit 210, 211 Spread code creation unit 320 Interleaving unit 400 Demultiplexing unit 401-404, 406, 407 Despreading unit 405 Control unit (CPU) 408-410 Error correction section 500 Deinterleaving section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Yano 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Takara Garaku 1-1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Hitachi Katsuhiko Tsunehara, Inventor Katsuhiko Tsunehara 1-280, Higashi-Koigakubo, Kokubunji-shi, Tokyo In-house Central Research Laboratory, Hitachi, Ltd. In company

Claims (13)

[Claims] Communication between a radio base station and a mobile terminal is performed by a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of the call control information. In the mobile communication method to be performed, the perch channel and the call control channel are arranged and transmitted on a time axis such that an error rate when the mobile terminal receives the call control channel is equal to or less than a threshold. A mobile communication method, comprising: 2. When the perch channel and the call control channel are arranged on a time axis, the call control channel and a portion provided in a part of the perch channel and the call control channel 2. The mobile communication method according to claim 1, wherein the non-code orthogonal portions are arranged such that an error rate when the call control channel is received is equal to or less than a threshold value. 3. The mobile communication method according to claim 1, wherein the call control channel is interleaved when the perch channel and the call control channel are arranged. 4. A communication between a radio base station and a mobile terminal by a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of the call control information. A mobile communication method, wherein the perch channel and the call control channel are arranged and transmitted on a time axis so that the mobile terminal can demodulate the call control channel. 5. A communication between a radio base station and a mobile terminal by a call control channel for transmitting call control information and a perch channel for transmitting a spreading code used for despread demodulation of said call control information. In the mobile communication method to be performed, the mobile terminal transmits power by controlling the power of the call control channel so that the mobile terminal can demodulate the call control channel. 6. A first channel generator for generating a call control channel by spreading call control information with a first spreading code, and transmitting a first spreading code used for despread demodulation of the call control information. A second channel generation unit that generates a perch channel, and a call control channel generated by the first channel generation unit and a perch channel generated by the second channel generation unit. A radio base station comprising: a channel multiplexing unit that arranges the call control channel so as to be demodulated. 7. The multiplexing unit can demodulate the call control channel and a part of the perch channel that is not code orthogonal to the call control channel when the call control channel is received. The radio base station according to claim 7, wherein the radio base station is arranged on a time axis. 8. The radio base station according to claim 7, wherein the multiplexing unit multiplexes the perch channel and the interleaved call control channel. 9. The power control unit for controlling transmission power of the call control channel, wherein the power control unit adjusts power so that the call control channel can be demodulated. Wireless base station. 10. A CDMA multiplexing technique for communicating between a base station and a mobile terminal by using a signal channel for transmitting user data and a perch channel for transmitting a spreading code used for demodulating the user data. In the mobile communication method, the signal channel has a call control channel that is time-division multiplexed, and the orthogonality of a spreading code between the call control channel and another channel provided in a part of the perch channel is low. A mobile communication method using a CDMA multiplexing technique, wherein a part to be lost is arranged without overlapping in time. 11. The radio base station, wherein the transmission power of the signal channel is Pu, the transmission power of the perch channel is Pp, the signal-to-interference power ratio required for receiving the signal channel without error is SIRr, When the spreading gain of the channel is Gd = 10 log (spreading rate / bit rate of the signaling channel), the transmission power of the perch channel and the signaling channel is controlled so as to satisfy the condition of Pu ≧ Pp + SIRr-Gd. Claim 10
A mobile communication method using the CDMA multiplexing technology described in the above. 12. A CDMA multiplexing technique for performing communication between a base station and a mobile terminal by using a signal channel for transmitting user data and a perch channel for transmitting a spreading code used for demodulating the user data. In the mobile communication method, the signal channel has a time-division multiplexed call control channel, and is configured by time-division multiplexing and interleaving a signal of the call control channel and user data. A mobile communication method using a CDMA multiplexing technique. 13. The radio base station, wherein the transmission power of the signal channel is Pu, the transmission power of the perch channel is Pp, the signal-to-interference power ratio required to receive the signal channel without error is SIRr, When the spread gain of the channel is Gd = 10 log (spread rate / bit rate of the signal channel), the transmission power of the perch channel and the signal channel is controlled so as to satisfy the condition of Pu ≧ Pp + SIRr-Gd. Claim 12
A mobile communication method using the CDMA multiplexing technology described in the above.