JPH11298369A - Multi-code adaptive modulation method and transmitter-receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-code adaptive modulation method and a transmitter-receiver capable of improving an S/N in the case that line quality is deteriorated, suppressing the degradation of error rate characteristics and improving transmission quality. SOLUTION: The quality of a line is detected in a line quality detection part 37, and in the case that the line quality is excellent, the number (parallel number) of codes used for modulation is increased. In a multi-code modulation part 35, the speed of data inputted from a transmission buffer is accelerated and the modulation is performed by the increased number of the codes. In the case that the line quality is deteriorated, the number of the codes used for the modulation is reduced, the speed of the data inputted from the transmission buffer is lowered and the modulation is performed by the reduced number of the codes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulation method and a transceiver for performing transmission and reception by performing spread spectrum modulation with a multicode, and more particularly to a multicode adaptive modulation method and a transceiver capable of adapting to channel quality.

[0002]

2. Description of the Related Art A spread spectrum communication method is a communication method in which data to be transmitted is spread by a spread sequence code and transmitted, and is a communication method excellent in data interference resistance, privacy and confidentiality. is there.

An important factor in performing spread spectrum communication is frequency use efficiency. When communication is performed using a communication channel having a limited frequency band, spread spectrum communication is performed within the limited frequency bandwidth. Are closely related to the data rate, the spreading sequence code rate, and the processing gain.

That is, if B: frequency bandwidth, Rc: spreading chip rate, PG: spreading gain (processing gain), and R: primary modulation rate, the relationship of B ≧ Rc = PG · R (1) holds. I have. Here, the processing gain is the difference between the S / N ratio (signal-to-noise ratio) of the input signal and the output signal in the receiving device.

For this reason, when the frequency bandwidth B is determined,
Chip rate R of spreading sequence code usable in the bandwidth
When the maximum value of c is determined, and when the processing gain PG is determined, the maximum value of the primary modulation rate R is also determined. When the primary modulation rate R is increased in order to increase the frequency use efficiency, the maximum value of the usable spreading chip rate Rc is determined, so that the processing gain PG decreases and the interference resistance, which is an advantage of spread spectrum, deteriorates. There is a problem.

Therefore, as a method for solving the above problem, data is converted into low-speed parallel data, and each parallel data is spread using a different spreading sequence code.
There is a multi-code modulation method in which these are added and transmitted.

Here, a multi-code modulation section and a multi-code demodulation section for realizing a conventional multi-code modulation method will be described with reference to FIGS. FIG. 6 is a configuration block diagram of a multi-code modulation unit that realizes a conventional multi-code modulation method, and FIG. 7 is a configuration block diagram of a multi-code demodulation unit that realizes a conventional multi-code modulation method. The case where the number of multicodes is 4 is shown.

In a multi-code modulation section for realizing a conventional multi-code modulation method, transmission data is converted by a serial / parallel converter 11 into parallel data (4 in the example of FIG. 6) as shown in FIG. After the spectrum is spread by multiplying each of the spreading sequence codes C1 to C4 generated by the spreading sequence code generation unit 12 by the multiplier 13, they are added by the adder 14, multi-valued, and transmitted.

On the other hand, in a multi-code demodulation unit for realizing a conventional multi-code modulation method, as shown in FIG. 7, received data is obtained by converting despread sequence codes C1 to C4 generated by a despread sequence code generation unit 22. The parallel data despread by the despreading unit 23 is converted into serial data by the parallel / serial converter 21 and output as received data.

In this conventional multi-code modulation method, since the transmission speed of data that is actually transmitted and then spread after parallelization is low, the original data rate (primary modulation rate) without lowering the processing gain. Can be raised.

The parallel spread spectrum (SS) system employs an intersymbol interference suppression technique to improve the trade-off between the information rate and the intersymbol interference and to increase the speed of the parallel S.
The S modulator / demodulator is described in Japanese Patent Application Laid-Open No. 200600518, and has a code division multiple access (CDM).
A) A method of acquiring a synchronization to reduce the circuit scale in a mobile communication system is described in Japanese Patent Application Laid-Open No. 8-32547, and a method of spread spectrum communication for removing noise by FFT frequency analysis is described in Japanese Patent Application Laid-Open No. H05-32547.
-75573.

[0012]

However, in the conventional multicode modulation method, when the number of parallel signals (the number of multicode signals) is increased to increase the data rate, the number of multilevel levels of the transmission signal increases in proportion to the number of parallel signals. If the total transmission power is constant, the S / N (signal-to-noise ratio) per code is reduced. If the line quality is poor, the error rate characteristic is deteriorated and the transmission quality is reduced. There was a problem.

The present invention has been made in view of the above circumstances, and changes the data rate and the number of parallel circuits according to the state of the line quality to improve the S / N ratio when the line quality deteriorates. It is an object of the present invention to provide a multi-code adaptive modulation method and a transceiver capable of suppressing the deterioration of error rate characteristics and improving transmission quality.

[0014]

According to the first aspect of the present invention, there is provided a multi-code adaptive modulation method in which when the line quality is good, the number of parallel transmission data is increased. In advance, spread the spectrum by increasing the data rate before parallelization, and if the line quality is poor, reduce the number of parallel transmission data and reduce the data rate before parallelization to spread the spectrum. When the line quality is deteriorated, the deterioration of the error rate characteristic is suppressed, and the transmission quality can be improved.

According to a second aspect of the present invention, there is provided a transmitter / receiver for transmitting data, a receiving unit for receiving data, and detecting a line quality from the received data. A line quality detection unit, a multi-code modulation unit that determines a parallel number according to the detected line quality, and spreads and multiplies the data parallelized with the parallel number by a spreading sequence code; and A multi-code demodulation unit for detecting multi-code number information indicating the number of parallelizations, and despreading and serializing with a despreading sequence code according to the multi-code number information; And a transmission buffer for changing the data rate at which the transmission data is output.The multi-code demodulation unit has a reception buffer for storing the despread reception data. When the line quality detected by the line quality detection unit is good, the data rate of the transmission data output from the transmission buffer is increased to perform spreading with a large parallel number, and when the line quality is poor, It is characterized in that the data rate of transmission data output from the transmission / reception buffer is reduced and spreading is performed with a small number of parallel data.

According to a third aspect of the present invention, there is provided a transceiver according to the second aspect, which solves the problems of the conventional example.
The line quality detection unit detects the line quality from the received data,
A line quality detection unit that outputs line quality ranking information ranked according to the line quality to a multicode modulation unit, wherein the multicode modulation unit transmits transmission data determined by the line quality ranking information from the line quality detection unit. A transmission buffer for increasing or decreasing the amount of data stored in accordance with the data output speed, and multi-code number information indicating a predetermined number of multi-codes corresponding to the line quality ranking information from the line quality detection unit. A multi-code number information adding unit to be added for each frame of transmission data; and a data from the multi-code number information adding unit at a predetermined parallel number corresponding to the line quality order information from the line quality detecting unit. A serial / parallel converter for parallelizing the data, a spreading sequence generation unit for generating a different spreading code for each of the maximum number of parallelizations,
A multi-code modulation unit including a multiplier that multiplies the data parallelized by the parallel converter and the spread sequence code from the spread sequence generation unit, and an adder that adds the data multiplied by the multiplier. It is characterized by having.

According to a fourth aspect of the present invention, there is provided a transceiver according to the second aspect of the present invention.
The multi-code demodulation unit includes a multi-code number information detection unit that detects multi-code number information included in the received data, and an inverse code generation unit that generates the same despread sequence code as the spread sequence code used for spreading the transmission data. A spreading code sequence generation unit, a despreading unit for despreading received data with a despreading sequence code generated by the despreading code sequence generation unit, and the despread data detected by the multicode number information detection unit. A parallel / serial converter that serializes according to the multi-code number information and outputs the data at a data rate corresponding to the multi-code number information, and a multi-code number information detected by the multi-code number information detection unit. A multi-code demodulation unit including a reception buffer for increasing / decreasing an amount of data to be stored and storing reception data serialized by the parallel / serial converter. It is.

[0018]

Embodiments of the present invention will be described with reference to the drawings. The multi-code adaptive modulation method and the transceiver according to the embodiment of the present invention provide a method for controlling the number of codes (parallel number) used for multi-code modulation and the data rate of transmission data according to the quality of the transmission path. If the data rate is bad, the data rate is reduced and spreading is performed with a small number of parallels.If the quality of the transmission path is good, the data rate is increased and the spreading is performed with a large number of parallels. By using the number and the data rate, the deterioration of the error rate characteristic can be improved.

A transceiver according to an embodiment of the present invention (this transceiver) will be described with reference to FIG. FIG. 1 is a configuration block diagram of a transceiver according to an embodiment of the present invention. This transceiver divides data into time units called frames and transmits and receives the data. As shown in FIG. 1, an antenna 31, a combiner (hybrid) 32,
A transmitting unit 33, a receiving unit 34, and a multi-code modulating unit 35
, A multi-code demodulation unit 36, and a channel quality detection unit 37.

Hereinafter, each part of the transceiver will be described in detail. The combiner 32 is generally called a hybrid, and outputs a signal arriving at the transmission / reception antenna 31 to the reception unit 34 and radiates a signal input from the transmission unit 33 via the transmission / reception antenna 31. It is.

The transmitting section 33 amplifies the signal input from the multi-code modulating section 35 to a constant power and outputs the signal to the combiner 32. The receiving unit 34 receives a signal input to the transmitting / receiving antenna 31 via the combiner 32 and outputs the signal to the multicode demodulating unit 36.

The multi-code modulation section 35 receives input of channel quality information from a channel quality detection section 37 described later, modulates the number of codes to be used based on the information, and modulates transmission data. , The transmission unit 3 at a constant transmission speed
3 is output.

The multi-code demodulator 36 despreads the input signal and outputs it as received data.
The value indicating the quality of the received signal is output to the line quality detection unit 37. Here, as the value indicating the quality of the received signal, the level of the received data, the error rate, and the like can be considered. still,
Since the multi-code modulation section 35 and the multi-code demodulation section 36 are characteristic parts of the present invention, they will be described later in detail with reference to FIGS.

The line quality detector 37 receives the value indicating the quality of the received signal from the multi-code demodulator 36, detects the line quality, and outputs information (line quality information) representing the line quality to the multi-code. The signal is output to the modulator 35.

As a specific method of detecting the line quality, a ROM for storing a reference value (threshold) of the quality of a received signal is provided, and the threshold value is received upon receiving an input of a value indicating the quality of the received signal. A method of comparing the value with the value, ranking the output line quality information, and outputting the information is considered.

That is, as shown in FIG.
If the line quality information is to be ranked in four stages of A to D, in the case of FIG. 4, A, A, A, B, B, C, C,. , B, A, A, B
Is output. FIG.
FIG. 4 is an explanatory diagram illustrating a relationship between a value indicating the quality of a received signal and line quality information.

Here, the line quality information of A to D is such that four codes are used for A and three codes are used for B.
It is conceivable that the number of codes to be used is directly expressed as one using two codes, one using two codes in C, and one using one code in D. Further, the line quality may be detected by a method of making a determination by program processing.

For example, in the multi-code modulation section 35, the speed of transmission data parallelized is 32 kwps (wo
rd per second), if the number of codes to be used is 2, 32 × 2 = 32 × 2 =
Data is output at a rate of 64 kbps (bits per second), and if the number of codes to be used is 4, the transmission buffer 4
It outputs data at a speed of 1 to 32 × 4 = 128 kbps.

Here, the multi-code modulation section 35 will be described with reference to FIG. FIG. 2 is a configuration block diagram of the multicode modulation unit 35. As shown in FIG. 2, the multi-code modulation unit 35 includes a transmission buffer 41, a multi-code number information adding unit 43, and a serial / parallel converter 44.
, A spreading code generation unit 45, a spreading unit 46, and an adder 47.

Hereinafter, these components will be described in detail.
The transmission buffer 41 receives and temporarily stores transmission data, receives and holds the line quality information input from the line quality detection unit 37, and uses a code used by the previously received line quality information. The transmission data is output to the multi-code number information adding unit 43 in series while adjusting the data speed in accordance with the number. That is, the transmission buffer 41
In Japanese Patent Application Laid-Open No. H11-229, the speed of output data is adjusted while adjusting the amount of data to be stored. For example, if the data rate is high, the amount of data to be stored is increased, and if the data rate is low, the amount of data to be stored is reduced.

The multi-code number information adding unit 43 is represented by the line quality information input from the line quality detecting unit 37.
Information on the number of codes to be used is added to one for one frame of transmission data.

The serial / parallel converter 44 parallelizes the signals input in series in accordance with the number of codes to be used, which is represented by the line quality information input from the line quality detector 37, and the number of parallelized signals. It is output as data.

It is considered that the serial / parallel converter 44 has a number of output terminals corresponding to the maximum value of the number of codes used, but FIG. Since the maximum number of codes is 4, the serial / parallel converter 44 is shown as having four output terminals a to d.

The spreading code generator 45 includes a spreading code generator which generates and outputs different spreading codes corresponding to the maximum number of codes to be used, and outputs the spreading codes as a set. Things.

The spreader 46 spreads the data by multiplying the plurality of spread sequence codes input from the spread sequence code generation unit 45 and the parallel data input from the serial / parallel converter 44, and outputs the data. Things. The adder 47 adds the parallel data spread by the spreader 46 and outputs the result as multi-valued data.

Next, the multi-code demodulation unit 36 will be described with reference to FIG. FIG. 3 is a configuration block diagram of the multicode demodulation unit 36. As shown in FIG. 3, the multi-code demodulation unit 36 includes a reception buffer 51, a multi-code number information detection unit 52, a parallel / serial converter 53, a despread sequence code generation unit 54, and a despread unit 55. It is composed of

Hereinafter, these components will be described in detail.
The despreading section 55 receives the received data and the despread sequence code
4 is multiplied by the despreading sequence code generated in step 4, and the received data is despread and output. Specifically, the despreading unit 55 can be realized using a matched filter, a correlator, or the like.

The despreading sequence code generation unit 54 is similar to the spreading sequence code generation unit 45 in the multicode modulation unit 35, and generates and outputs the same spreading sequence code as the spreading sequence code generation unit 45, respectively. Things.

The parallel / serial converter 53 converts a parallel signal input from the despreading unit 55 in accordance with information on the number of codes to be used, which is input in advance from the multicode number information detecting unit 52 described later. This is to convert to a serial signal.

The parallel / serial converter 53 is considered to have a number of input terminals corresponding to the maximum number of codes to be used. Since the maximum value of the number is set to 4, the parallel / serial converter 53 is illustrated as having four input terminals a to d.

That is, if the number of previously input codes is 2, the parallel / serial converter 53 converts the data input from the terminals a and b into serial signals and adjusts the data rate. And output it. The adjustment of the data rate will be described later.

The multi-code number information detecting section 52 has a parallel /
The multi-code number information added to the head of each frame is detected from the signal output from the serial converter 53 and output to the parallel / serial converter 53 and the reception buffer 51.

The reception buffer 51 includes a parallel / serial converter 5
3 is temporarily stored, and is read at a constant data rate while increasing or decreasing the amount of stored data. For example, when the input data rate is high, the output data amount is increased, and when the input data rate is low, the output data amount is reduced, and the data rate output from the reception buffer 51 is kept constant. I have.

Next, the operation of the transceiver will be described. In the following description, it is assumed that the line quality is ranked in four stages as in the example shown in FIG. That is, A, B, C,
D.

In this case, for example, three thresholds corresponding to information such as the reception level indicating the quality of the line are provided, and the line quality detector 37 compares each threshold with the information indicating the quality of the line. Then, the above-described four-stage ranking is performed.

First, data to be transmitted is stored in the transmission buffer 41 of the multi-code modulation section 35. The transmission buffer 41 receives the input of the line quality information from the line quality detection unit 37, holds the input, and transfers the data corresponding to the number of codes to be used, which is represented by the previously input line quality information, to the data rate. Adjust and multi-code number information adding section 43
Output to

Then, the multi-code number information adding section 43 of the multi-code modulation section 35 outputs information on the number of codes corresponding to the line quality information inputted this time from the line quality detecting section 37 to the data inputted from the transmission buffer 41. The data is added to the leading part and output to the serial / parallel converter 44.

That is, the information of the number of codes to be used, which is added to the head of the data, indicates the number of codes of the next frame. Thus, data for one frame is generated as shown in FIG. FIG. 5 is an explanatory diagram illustrating a format of a frame transmitted and received by the transceiver.

Then, the serial / parallel converter 44 is inputted from the multi-code number information adding section 43 so as to correspond to the number of codes to be used, which is represented by the line quality information inputted from the line quality detecting section 37. The data for one frame is converted into parallel data. Specifically, in the example of FIG. 2, the case where the line quality information is “C” (the number of codes to be used is 2) is illustrated, so that the serial / parallel converter 44
Are output in parallel from the two, and from the terminals c and d,
"0" data is output.

On the other hand, since the maximum number of codes to be used is 4, the spread sequence code generation section 45 generates four spread sequence codes C1 to C4.

The spreading unit 46 multiplies the corresponding spread sequence code input from the spreading sequence code generation unit 45 by the data converted in parallel, and outputs the result to the adder 47. The multiplied data is added and output to the transmission unit 33.

In the example of FIG. 2, the data output from the terminals a and b by the serial / parallel converter 44 are multiplied by the spreading sequence codes C1 and C2, respectively. On the other hand, since the output of the terminals c and d is stopped, no multiplication is performed as a result. Then, the transmitting unit 33 radiates data via the combiner 32 and the antenna 31.

Here, assuming that the speed of the parallel transmission data is 32 kwps, as shown in the following Table 1, when the line quality information is "A", the transmission buffer 41
, The speed of the data input to the multicode number information adding unit 43 becomes 128 kbps.

[0054]

[Table 1]

The data to which the multicode number information has been added is parallelized into a maximum of four by the serial / parallel converter 44, so that the speed of the data converted in parallel is 32 kwp.
s.

For example, when the line quality information is “C”,
The speed of data input from the transmission buffer 41 to the multi-code number information adding unit 43 is 64 kbps. However, since the data to which the multicode number information is added is converted into 1: 2 parallel data by the serial / parallel converter 44, the data speed after the parallelization does not change at 32 kwps, and It can be seen that even if the number changes, the speed of the data output from the serial / parallel converter 44 is always constant at 32 kWps.

That is, if the number of codes to be used is 2, the data input at 64 kbps is parallelized into two, so that the transmission is performed at a rate of 64/2 = 32 kWps.

On the other hand, the signal arriving at antenna 31 is output to receiving section 34 via combiner 32, and receiving section 34 receives the signal and outputs it to multicode demodulating section 36.

The despreading sequence code generator 54 of the multi-code demodulation unit 36 outputs the generated spreading sequence code to the despreading unit 55, and the despreading unit 55 converts the signal input from the receiving unit 34 into the spread sequence code. To despread and convert the parallel / serial converter 5
Output to 3. On the other hand, the multi-code number information detecting section 52 of the multi-code demodulating section 36 outputs to the parallel / serial converter 53 the information on the number of codes to be used added to the previously received frame.

Then, the parallel / serial converter 53 converts parallel data into serial data based on the information on the number of codes input from the multicode number information detecting section 52, adjusts the data speed, and receives the data. The data is output to the reception buffer 51 as data.

That is, if the number of codes input from the multi-code number information detecting section 52 is 2, the data rate is output to the reception buffer 51 at 64 kbps, and if the number of codes is 3, the data rate is Is output as 96 kbps.

By adjusting the amount of received data stored in the reception buffer 51, the speed at which data is read from the reception buffer 51 can always be kept constant. There is an effect that the speed can be made faster than in the case of single code transmission with the same transmission quality.

Specifically, the speed of data output from the transmission buffer 41 to the multicode number information adding unit 43 is:
The speed of data read from the reception buffer 51 can always be set to 128 kbps, although it varies depending on the number of codes used between 32 kbps and 128 kbps.

On the other hand, the multi-code number information detecting section 52
The multi-code number information added to the frame is detected, and the information is output to the parallel / serial converter 53 as the number of codes used in the next frame.

As described above, according to the present transceiver, the number of codes (parallel number) to be used is adjusted according to the line quality, and S
The transmission quality can be improved without deteriorating the error rate characteristic even when the line quality is deteriorated, without impairing the advantage of the multi-code modulation method of improving the data rate while maintaining the processing gain by improving the / N ratio. There is an effect that can be maintained.

[0066]

According to the present invention, when the line quality is good, the number of parallel transmission data is increased, the data rate is increased to spread the spectrum, and when the line quality is bad, the transmission data The multi-code adaptive modulation method reduces the number of parallels and spreads the data at a reduced data rate, so if the line quality deteriorates, the effect of suppressing the deterioration of the error rate characteristic and improving the transmission quality can be obtained. is there.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a transceiver according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a multicode modulation unit 35.

FIG. 3 is a configuration block diagram of a multi-code demodulation unit 36.

FIG. 4 is an explanatory diagram illustrating a relationship between a value indicating the quality of a received signal and line quality information.

FIG. 5 is an explanatory diagram showing a format of a frame transmitted and received by the transceiver.

FIG. 6 is a configuration block diagram of a multi-code modulation unit that realizes a conventional multi-code modulation method.

FIG. 7 is a block diagram illustrating a configuration of a multi-code demodulation unit that implements a conventional multi-code modulation method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Serial / parallel converter, 12 ... Spread sequence code generation part, 13 ... Multiplier, 14 ... Adder, 21 ... Parallel / serial converter, 22 ... Despread sequence code generation part, 23 ... Despread part, 31 ... antenna, 32 ... combiner, 33 ... transmitter, 34 ... receiver, 35 ... multi-code modulator,
36: Multi-code demodulator, 37: Line quality detector, 41: Transmission buffer, 43: Multi-code number information adder, 44: Serial / parallel converter, 45: Spread sequence code generator, 46: Spreader, 47 ... Adder, 51
... Reception buffer, 52 ... Multi-code number information detector,
53: parallel / serial converter, 54: despreading sequence code generation unit, 55: despreading unit

Claims (4)

[Claims] When the line quality is good, the number of parallel transmission data is increased, the data rate before parallelization is increased, and spectrum spreading is performed. A multi-code adaptive modulation method characterized in that the number of parallel circuits is reduced, and the data rate before parallel processing is reduced to perform spread spectrum. 2. A transmitting unit for transmitting data, a receiving unit for receiving data, a line quality detecting unit for detecting a line quality from the received data, and determining a parallel number according to the detected line quality; A multi-code modulation unit that spreads and multiplies the data parallelized with the parallel number by a spreading sequence code, detects multi-code number information indicating the parallel number from received data, and according to the multi-code number information. A multi-code demodulation unit that performs despreading and serialization with a despreading sequence code, wherein the multi-code modulation unit stores transmission data and has a transmission buffer that changes a data rate at which the transmission data is output. The multi-code demodulation unit has a reception buffer for storing despread reception data, and when the line quality detected by the line quality detection unit is good, the transmission buffer If the line quality is poor, the data rate of the transmission data output from the transmission / reception buffer is reduced and the data rate of the transmission data output from the transmission / reception buffer is reduced to reduce the number of parallel transmissions. A transceiver characterized by performing. 3. A line quality detecting section for detecting a line quality from received data and outputting line quality ranking information ranked according to the line quality to a multi-code modulation section, A modulator configured to increase or decrease the amount of data stored in accordance with the data output speed of the transmission data determined by the line quality rank information from the line quality detector; and a line quality rank from the line quality detector. A multi-code number information adding unit that adds multi-code number information indicating a predetermined number of multi-codes corresponding to the information for each frame of the transmission data, and corresponds to line quality order information from the line quality detection unit. And a serial / parallel converter for parallelizing the data from the multicode number information adding unit with a predetermined parallelization number, and different expansions each corresponding to the maximum parallelization number. A spreading sequence generator for generating a sequence code, a multiplier for multiplying the data parallelized by the serial / parallel converter with a spreading sequence code from the spreading sequence generator, and a multiplier multiplied by the multiplier. 3. A multi-code modulator comprising: an adder for adding data.
Transceiver as described. 4. A multi-code demodulation unit for detecting multi-code number information included in received data, and a despreading sequence identical to a spreading sequence code used for spreading transmission data. A despreading code sequence generating unit for generating a code, a despreading unit for despreading received data with a despreading sequence code generated by the despreading code sequence generating unit, A parallel / serial converter for serializing according to the multicode number information detected by the detection unit and outputting the data at a data rate corresponding to the multicode number information; and a multicode number detected by the multicode number information detection unit. A multi-code demodulation unit comprising: a reception buffer that increases / decreases an amount of data stored in accordance with information and stores reception data serialized by the parallel / serial converter. 3. The transceiver according to claim 2, wherein: