JP2003032220A - Transmitting device, receiving device, and wireless communication method - Google Patents

Abstract

(57) [Problem] To suppress peak power without performing non-linear processing in multicarrier CDMA wireless communication. An amplitude measuring unit (108) includes an IFFT unit (107).
The peak power of the output signal is measured, and it is determined whether the peak power exceeds a preset threshold.If the peak power exceeds the threshold, the peak power is discarded.If the peak power is lower than the threshold, Is output to the wireless transmission unit 109. The scrambling code selection unit 103 selects a predetermined first code number when the peak power is equal to or less than the threshold, and sets the code number next to the previously selected scrambling code when the peak power exceeds the threshold. Select the corresponding scrambling code. The scrambling code multiplication unit 104 multiplies the output signal of the multiplexing unit 102 by a scrambling code when the peak power is equal to or less than the threshold, and adds a scrambling code to the signal stored in the internal memory when the peak power exceeds the threshold. Multiply by

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a digital communication system and is used for OFDM (Orthogonal Frequency D
ivision Multiplexing) and other multicarrier modulation schemes and CDMA (Code Division Multiple Access)
The present invention relates to a transmitting device, a receiving device, and a wireless communication method that perform wireless communication by combining the above methods.

[0002]

2. Description of the Related Art In recent years, in wireless communication, especially mobile communication,
In addition to voice, various information such as images and data are targets for transmission. In the future, the demand for transmission of various contents is expected to become higher and higher, so the need for highly reliable and high-speed transmission will further increase. However, when high-speed transmission is performed in mobile communication, the influence of delayed waves due to multipath cannot be ignored, and transmission characteristics deteriorate due to frequency selective fading.

An MC (multi-carrier) modulation method has been attracting attention as one of techniques for preventing frequency selective fading. The multi-carrier modulation method is a technology that results in high-speed transmission by transmitting data using a plurality of carriers (subcarriers) whose transmission speed is suppressed to the extent that frequency selective fading does not occur. Especially OF
The DM modulation method has the highest frequency utilization efficiency among the multi-carrier modulation methods because a plurality of subcarriers in which data is arranged are orthogonal to each other. Also, O
The FDM modulation method can be realized with a relatively simple hardware configuration. For these reasons, various studies have been conducted on the OFDM modulation method as a measure against frequency selective fading.

A spread spectrum system is another technique for countering the frequency selective fading. The spread spectrum system is a system in which a signal is spread on a frequency axis by a spreading code called a PN code to obtain a spreading gain, thereby enhancing interference resistance. The spread spectrum method includes a direct spread method and a frequency hopping method. Among them, CDMA (Code Divisio) using the direct spread method is used.
It has been decided that the n multiple access) method will be adopted in IMT-2000, which is the next-generation mobile communication.

The MC-CDMA system, which is a combination of the MC modulation system and the CDMA system, has recently attracted attention. The MC-CDMA system is roughly classified into a time domain spreading system and a frequency domain spreading system. The present invention deals with the frequency domain spreading method.

The frequency domain spreading method will be described below. FIG. 10 is a schematic diagram showing the state of digital symbols before modulation processing, and FIG. 11 is a schematic diagram showing the arrangement of each chip after modulation processing by the frequency domain spreading method. In the frequency domain spreading method, N digital symbols (FIG. 10), which are serial data sequences, have a spreading factor M per symbol.
Is multiplied by the spreading code. The spread chips are subjected to IFFT processing sequentially in parallel for M symbols one symbol at a time. As a result, N OFDM symbols of M subcarriers are generated. That is, in the frequency domain spreading method, the chips after spreading are arranged on the frequency axis at each time (FIG. 11). In other words, the chip after diffusion
They are arranged on different subcarriers.

Assuming that one digital symbol before modulation processing uses a radio resource of time width T and frequency bandwidth B in the same manner as described above (FIG. 10), one chip has time width N and frequency band after modulation processing. The width B will be used. Therefore, the area occupied by one digital symbol in the time-frequency domain is M × T × B, which is M times the area occupied by one digital symbol before the modulation processing.

Here, for example, the number of digital symbols N
= 8 and spreading factor M = 8, the signal pattern of the OFDM symbol generated by the frequency domain spreading method is as shown in FIG. As shown in this figure, in the frequency domain spreading method, eight OFDM symbols are sequentially generated from t0 to t7 corresponding to eight digital symbols distinguished by grayscale of black and white on the time axis. At this time, eight chips in each digital symbol are assigned to different subcarriers f1 to f8.

By using the MC-CDMA system,
It is possible to realize efficient frequency reuse and obtain a statistical multiplexing effect. Moreover, single carrier CD
Data transmission faster than MA can also be realized. Note that frequency reuse means that the same frequency can be used in adjacent cells. In addition, the statistical multiplexing effect means that when the presence or absence of data occurs randomly by the user, the energy reduction in the sections that do not transmit to each other,
This is an effect that can accommodate a larger number of user signals as compared with the case of continuous transmission.

[0010]

However, in the MC-CDMA system of the frequency domain spreading system, since parallel transmission is performed by using a plurality of subcarriers, the peak power becomes extremely larger than the average power at the time of transmission. Will occur. In addition, when nonlinear processing such as peak clipping is performed to suppress peak power, inter-subcarrier interference increases and characteristics deteriorate, and out-of-band unwanted radiation increases and interferes with out-of-band signals. Will be given.

The present invention has been made in view of the above points, and in MC-CDMA wireless communication, it is possible to suppress peak power without performing non-linear processing, a transmitting device, a receiving device, and a wireless communication method. The purpose is to provide.

[0012]

A transmitting apparatus according to the present invention comprises a scramble code setting means for setting a scramble code, a scramble code multiplying means for multiplying a spread-multiplexed signal by the set scramble code, and a scramble code. Multicarrier modulation means for performing multicarrier modulation processing on the multiplied signal and the peak power of the multicarrier modulated signal are measured, and it is determined whether the measured peak power exceeds a preset threshold value. And a scrambling code setting means for setting a scrambling code based on the determination result of the amplitude measuring means.

In the transmitting apparatus of the present invention, the scramble code setting means is one of a plurality of held scramble codes.
If the peak power of the signal selected by selecting one of the two scrambling codes is larger than the threshold value, another scrambling code is selected.

According to these configurations, a plurality of scramble codes are associated with the code numbers, sequentially selected, and sequentially selected, and the peak power of the process of multiplying the selected scramble code by the spread multiplexed signal is less than or equal to the threshold value. It is possible to suppress the peak power without performing non-linear processing by repeating the above process.

In the transmitter of the present invention, the scramble code setting means cuts out a predetermined amount of chips from the beginning of the scramble code and attaches it to the rear end when the peak power of the signal multiplied by the scramble code is larger than the threshold value. A configuration for generating a new scramble code is adopted.

According to this structure, the process of multiplying the generated scramble code by the spread multiplexed signal is repeated until the peak power becomes equal to or less than the threshold value, thereby suppressing the peak power without performing the non-linear process. You can Also,
Since only one scramble code is stored in the transmitter and the receiver, the memory capacity can be reduced.

The transmitting apparatus of the present invention has a configuration in which the scramble information representing the scramble code selected by the scramble code setting means is transmitted to the receiving apparatus of the communication partner.

The transmitting apparatus of the present invention has a configuration for transmitting scramble information representing the number of the first chip of the scramble code generated by the scramble code setting means to the receiving apparatus of the communication partner.

According to this structure, the receiving device can specify the scramble code that has been multiplied, and can take out the data.

The receiving apparatus of the present invention comprises multicarrier demodulating means for performing multicarrier demodulation processing on the signal transmitted from the transmitting apparatus, and extracting means for extracting scramble information from the signal transmitted from the transmitting apparatus. A scramble restoration means for multiplying a scramble code represented by the extracted scramble information by a multicarrier demodulated signal to restore a spread-multiplexed signal, and a despreading means for despreading the restored spread-multiplexed signal to extract data. The configuration including is adopted.

According to this configuration, the scramble code being multiplied can be specified and the data can be taken out.

In the receiving apparatus of the present invention, the multi-carrier demodulation means for performing multi-carrier demodulation processing on the signal transmitted from the above-mentioned transmission apparatus, and the signal subjected to the multi-carrier demodulation processing are multiplied by the transmission apparatus. Scrambling restoration means for multiplying each scrambling code that may possibly occur, despreading means for despreading each signal multiplied by the scrambling code, and selection of extracting the largest power among the despread signals as data And a configuration including means.

According to this structure, the receiving device can take out the data even if the transmitting device does not transmit the scramble information, so that the data can be efficiently transmitted and the structure of the transmitting device can be simplified. it can.

The base station apparatus of the present invention has a configuration in which any one of the above is provided with a transmitting apparatus. Further, the communication terminal device of the present invention has a configuration including any one of the above transmission devices. A base station apparatus of the present invention has a configuration including the above receiving apparatus. A communication terminal device of the present invention has a configuration including the above receiving device.

With these configurations, the transmission side device can suppress the peak power without performing the non-linear processing, so that highly reliable and high speed wireless communication can be performed.

The wireless communication method of the present invention employs a method in which the transmitter sets a scramble code in which the peak power of the multicarrier-modulated signal is less than or equal to a preset threshold value and multiplies the spread-multiplexed signal. .

In the wireless communication method of the present invention, the transmitting device multiplies the spread-multiplexed signal by the scrambling code to perform the multi-carrier modulation process, and the first step of measuring the peak power of the multi-carrier modulated signal. Two steps,
If the peak power is greater than a preset threshold,
The scramble code is changed, the first step and the second step are performed again, and when the peak power is equal to or less than the threshold value, the signal after the second step is wirelessly transmitted to the receiving device.

In the wireless communication method of the present invention, the transmitting device transmits scramble information representing the multiplied scramble code to the receiving device, and the receiving device multi-carrier demodulates the signal transmitted from the transmitting device. And then
The scramble information is extracted from the signal transmitted from the transmitter, the scramble code represented by the extracted scramble information is multiplied by the signal subjected to the multicarrier demodulation processing to restore the spread-spectrum multiplexed signal, and the restored spread-spectrum multiplexed signal is obtained. The method of extracting data by despreading is adopted.

By these methods, it is possible to suppress the peak power without the transmitter performing the non-linear processing. In addition, the receiving device can specify the scramble code that has been multiplied, and can extract the data.

In the radio communication method of the present invention, the receiving device may perform multicarrier demodulation processing on the signal transmitted from the transmitting device, and the signal subjected to the multicarrier demodulation processing may be multiplied by the transmitting device. Of the despread signal, the signal with the highest power is taken out as data.

According to this method, the receiving device can retrieve the data even if the transmitting device does not transmit the scramble information, so that the data can be efficiently transmitted and the structure of the transmitting device can be simplified.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention uses the MC-CDMA system to multiply a spread multiplexed signal by a scrambling code used for cell identification and the like, and to combine a spreading code and a scrambling code. The present invention has been made paying attention to the change in peak power.

That is, the essence of the present invention is to select a scramble code whose peak power is equal to or less than a preset threshold value by preparing a plurality of scramble codes in the transmitter and inform the receiver of the selected scramble code. That is.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the OFDM modulation method will be described as an example of the multi-carrier modulation method. That is, a case where the transmitted multi-carrier signal is an OFDM symbol will be described.
In each of the following embodiments, a case will be described where the base station device transmits data and the communication terminal device receives the data.

(Embodiment 1) FIG.1 is a block diagram showing a configuration of a base station apparatus according to Embodiment 1 of the present invention. The base station apparatus shown in FIG.
1-n (n is a natural number of 2 or more), the multiplexing unit 102,
Scramble code selecting section 103, scramble code multiplying section 104, scramble information generating section 105, S / S
P (serial / parallel) conversion unit 106 and IFFT
(Inverse Fourier transform) section 107, amplitude measuring section 108,
The wireless transmitter 109 and the antenna 110 are provided.

Spreading sections 101-1 to 101-n obtain spread signals by multiplying data destined for each user by a spreading code unique to the user. The multiplexing unit 102 multiplexes the spread signals output from the spreading units 101-1 to 101-n and outputs the multiplexed signals to the scramble code multiplying unit 104.

Scramble code selecting section 103 stores a plurality of scramble codes known to the receiving party in association with code numbers, and scramble code based on the comparison result between the peak power measured by amplitude measuring section 108 and the threshold value. Is output to the scramble code multiplication unit 104, and the corresponding code number is output to the scramble information generation unit 10
Output to 5. The detailed internal configuration of the scramble code selection unit 103 will be described later.

The scramble code multiplication unit 104 temporarily stores the output signal of the multiplexing unit 102 in the internal memory.
Then, scramble code multiplication section 104 outputs the signal input from multiplexing section 102 to the scramble code selected by scramble code selection section 103 based on the comparison result between the peak power measured by amplitude measurement section 108 and the threshold value. Alternatively, the signal stored in the internal memory is multiplied and S
It is output to the / P conversion unit 106. The detailed internal configuration of the scramble code multiplication unit 104 will be described later.

The scramble information generating section 105 generates scramble information, which is information indicating the code number of the scramble code selected by the scramble code selecting section 103, and outputs it to the S / P converting section 106.

S / P conversion section 106 converts the output signal of scramble code multiplication section 104, which is a serial data series, into a parallel data series (multicarrier modulation) and puts the data on a predetermined subcarrier. In addition, the S / P conversion unit 106
Puts the scramble information output from scramble information generating section 105 on a subcarrier other than the one carrying the data. For example, if the number of subcarriers used is 10
In the case of 0 lines, 95 lines are used to carry data and the remaining 5 lines are used to carry scramble information.

The IFFT section 107 is an S / P conversion section 106.
The output signal of is subjected to inverse Fourier transform and output to the amplitude measuring unit 108.

Amplitude measuring section 108 measures the peak power of the output signal of IFFT section 107, determines whether or not the peak power exceeds a preset threshold value, and selects a control signal indicating the determination result by scramble code selection. It is output to the unit 103 and the scramble code multiplication unit 104. In addition, the amplitude measuring unit 108 discards the output signal of the IFFT unit 107 when the peak power exceeds the threshold value, and outputs it to the wireless transmission unit 109 when the peak power is less than or equal to the threshold value.

Radio transmitting section 109 performs predetermined radio processing such as amplification and up-conversion on the signal output from amplitude measuring section 108, and radio-transmits from antenna 110.

Next, the scramble code selection unit 103 and scramble code multiplication unit 10 of the base station apparatus shown in FIG.
The internal configuration and operation of No. 4 will be described in detail with reference to FIG.

The scramble code selection unit 103 stores a plurality of scramble codes {C ₁ , C ₂ , ... C _m } known to the receiving party in the internal memory 201 as code numbers "1, 2, ...
m ”(m is a natural number of 2 or more) and stored. The code number also indicates the order in which the same data is multiplied. Then, when the peak power measured by amplitude measuring section 108 is equal to or less than the threshold value, scramble code selecting section 103 selects scramble code {C ₁ } having a code number of "1".
On the other hand, the scramble code selection unit 103 has the amplitude measurement unit 1
If the peak power measured at 08 exceeds the threshold value, the scramble code corresponding to the code number next to the previously selected scramble code is selected. Then, scramble code selecting section 103 outputs the selected scramble code to scramble code multiplying section 104, and outputs the corresponding code number to scramble information generating section 105.

The scramble code multiplication unit 104 has an internal memory 211, a selection switch 212, and a multiplier 213, and outputs the output signal of the multiplexing unit 102 to the internal memory 211.
To store. Then, the scramble code multiplication unit 104
When the peak power measured by the amplitude measuring unit 108 is less than or equal to the threshold value, the selection switch 212 is set to the multiplexing unit 102.
The output signal of the multiplexing unit 102 is output to the multiplier 213 by connecting to. On the other hand, when the peak power measured by the amplitude measuring unit 108 exceeds the threshold value, the scramble code multiplying unit 104 connects the selection switch 212 to the internal memory 211 so that the signal stored in the internal memory 211 can be output. Output to the multiplier 213. Multiplier 21
In 3, the input signal is multiplied by the scramble code.

By these operations in scramble code selecting section 103 and scramble code multiplying section 104, the signal from multiplexing section 102 is first multiplied by scramble code {C ₁ } and then after scramble code multiplication. The scrambling code is sequentially multiplied until the peak power of the signal of s falls below the threshold.

FIG. 3 is a flowchart showing a scramble code selection procedure of the base station apparatus according to Embodiment 1 of the present invention. In addition, in FIG. 3, j indicates a code number. First, step (hereinafter abbreviated as “ST”) 301, ST30
In 2, the scramble code selection unit 103 selects the scramble code {C ₁ } whose code number is "1".

Then, in ST303, the amplitude measuring section 108
At, the peak power of the signal multiplied by the scramble code {C ₁ } is measured, and the threshold value is judged. The result of the threshold judgment,
If the peak power exceeds the threshold value, ST304, ST
In 302 and ST303, scramble code selection section 103
Is a scramble code {C ₂ } whose code number is "2".
Is selected and the threshold value determination is performed again. Hereinafter, when the peak power exceeds the threshold value as a result of the threshold value determination, the scramble code selection unit 103 selects the scramble code corresponding to the code number next to the previously selected scramble code, and S
The processes of T304, ST302, and ST303 are repeated.

On the other hand, as a result of the threshold value judgment in ST303, if the peak power is below the threshold value, the scramble code {C _j }
In ST305, the signal multiplied by
It is wirelessly transmitted from the antenna 110. And ST30
In step 6, if there is the next data, ST301 to ST305
The process of is repeated.

FIG. 4 is a block diagram showing the configuration of the communication terminal apparatus according to Embodiment 1 of the present invention. The communication terminal apparatus illustrated in FIG. 4 is an apparatus that receives a signal from the base station apparatus illustrated in FIG. 1, and includes an antenna 401 and a wireless reception unit 40.
2, an FFT (Fourier transform) unit 403, a P / S (parallel / serial) conversion unit 404, a scramble information extraction unit 405, a scramble restoration unit 406, and a despreading unit 407.

Radio receiving section 402 performs predetermined radio processing such as amplification and down conversion on the signal received by antenna 401, and outputs the result to FFT section 403. FF
The T unit 403 Fourier-transforms the output signal of the wireless reception unit 402 and outputs it to the P / S conversion unit 404.

P / S conversion section 404 converts the output signal of FFT section 403, which is a parallel data series, into a serial data series (multicarrier demodulation), outputs scramble information to scramble information extraction section 405, and scrambles the data. Output to the restoration unit 406.

The scramble code extraction section 405 identifies the code number of the scramble code used in the base station apparatus based on the input scramble information, and outputs the code number to the scramble restoration section 406.

The scramble restoration section 406 multiplies the signal input from the P / S conversion section 404 by the scramble code of the code number specified by the scramble code extraction section 405 to obtain a multiplexed spread signal.

The despreading unit 407 is the scramble restoration unit 4
The output signal of 06 is multiplied by the spreading code unique to the same user as that of the base station apparatus to obtain data addressed to the user.

As described above, according to the present embodiment, the transmitting apparatus prepares a plurality of scramble codes in association with the code numbers and sequentially selects them, and multiplies the spread signal by the selected scramble code. By repeating the process until the peak power becomes equal to or lower than the threshold value, the peak power can be suppressed without performing the non-linear process. Further, the transmitting device transmits the code number to the receiving device, so that the receiving device can specify the scramble code that has been multiplied and can take out the data.

(Embodiment 2) FIG.5 is a block diagram showing a configuration of a base station apparatus according to Embodiment 2 of the present invention. In the base station apparatus of FIG. 5, the same components as in FIG. 1 are assigned the same reference numerals as those in FIG. 1 and their explanations are omitted.
Compared with FIG. 1, the base station apparatus shown in FIG. 5 has a configuration in which the scramble code selection unit 103 is deleted and a scramble code generation unit 501 is added instead.

Amplitude measuring section 108 measures the peak power of the output signal of IFFT section 107, determines whether or not the peak power exceeds a preset threshold value, and scramble-codes a control signal indicating the determination result. It is output to the unit 501 and the scramble code multiplication unit 104.

The scramble code generation unit 501 stores one scramble code, and performs a cyclic process for cutting out the first chip of the stored scramble code and attaching it to the rear end every time the control signal is input from the amplitude measuring unit 108. Then, a scramble code to be output to the scramble code multiplication unit 104 is generated. Also, the head chip number of the generated scramble code is output to the scramble information generation unit 105.

FIG. 6 is a diagram for explaining the processing of the scramble code generator 501. 6, the scrambling code 601-1 is a scrambling code which is stored in the scramble code generation unit 501, first, the head chip ch _1, turn ch _1, ch _2, ... p number (p of ch _p is It is composed of two or more natural numbers).

Then, when the control signal from the amplitude measuring section 108 is input to the scramble code generating section 501, the scramble code generating section 501 causes the scramble code 601.
The leading chip ch _{1 of} -1 is cut out and attached to the trailing end of the chip to perform a circulation process. As a result, chip ch ₂ is at the top, and ch _2, c
A scramble code 601-2 composed of p (p is a natural number of 2 or more) chips of h ₃ , ..., Ch _p , ch ₁ is newly generated. After that, the scramble code generation unit 501
By repeating the same processing every time the control signal is input from the amplitude measuring unit 108, the scramble code 601-i (1 ≦ i ≦ p) having the chip ch _i as the head is generated and output to the scramble code multiplying unit 104. The top chip number i
Is output to the scramble information generation unit 105.

The scramble code multiplication unit 104 inputs the scramble code generated by the scramble code generation unit 501 from the multiplexing unit 102 based on the comparison result between the peak power measured by the amplitude measurement unit 108 and the threshold value. The signal or the signal stored in the internal memory is multiplied and output to the S / P conversion unit 106.

The scramble information generation unit 105 generates the head chip number of the scramble code generated by the scramble code generation unit 501 as scramble information,
It is output to the S / P conversion unit 106.

FIG. 7 is a flowchart showing a scramble code generating procedure of the base station apparatus according to Embodiment 2 of the present invention. In FIG. 7, i indicates a chip number. First,
In ST701 and ST702, the scramble code generation unit 5
01 is a scramble code 60 starting from chip ch _1.
Select 1-1.

Then, in ST703, the amplitude measuring unit 108
At, the peak power of the signal multiplied by the scramble code 601-1 is measured, and the threshold value is determined. If the peak power exceeds the threshold as a result of the threshold determination, ST704,
In ST702 and ST703, the scramble code generation unit 5
01 is a scramble code 60 starting from chip ch ₂
Select 1-2 and perform threshold determination again. Hereinafter, when the peak power exceeds the threshold value as a result of the threshold value determination, the scramble code selection unit 103 cuts out the first chip of the previously selected scramble code and performs a cyclic process to attach it to the rear end to generate a new scramble code. ST704, S
The processes of T702 and ST703 are repeated.

On the other hand, as a result of the threshold value judgment in ST703, if the peak power is below the threshold value, the scramble code 601-
The signal multiplied by i is transmitted to the wireless transmission unit 10 in ST705.
9. Wirelessly transmitted from the antenna 110. And ST
If there is the next data in 706, ST701 to ST7
The processing of 05 is repeated.

The configuration of the communication terminal apparatus according to the present embodiment is the same as that shown in FIG. 2 shown in above-mentioned Embodiment 1. However,
The scramble information extraction unit 405 identifies the leading chip number of the scramble code used in the base station apparatus based on the input scramble information, and the scramble restoration unit 406.
However, it differs from the first embodiment in that a scramble code having a chip with the specified start chip number as the head is generated.

As described above, according to the present embodiment, the transmission apparatus generates a new scramble code by the above cyclic processing and multiplies the generated scramble code by the spread multiplexed signal. By repeating the process until it becomes less than or equal to the threshold value, it is possible to suppress the peak power without performing non-linear processing. Further, the transmitting device transmits the number of the leading chip to the receiving device, so that the receiving device can generate a scramble code that has been multiplied,
Data can be retrieved. Further, according to the present embodiment, since the number of scramble codes stored in the transmitting device and the receiving device is one, it is possible to reduce the memory capacity as compared with the first embodiment.

In the present embodiment, the case where a new scramble code is generated by cutting out one chip from the scramble code and performing the cyclic process of attaching the chip to the rear end has been described, but the present invention cuts out in the cyclic process. It is also possible to cut out a plurality of chips if the amount of chips is predetermined between the devices.

Further, in the above-mentioned first and second embodiments,
Although the case where the scramble information is transmitted by being carried on a subcarrier other than the one carrying the data has been described, the present invention is not limited to this, and the same effect can be obtained by transmitting the scramble information by another method. it can.

(Third Embodiment) In the third embodiment, the case where the transmitting apparatus does not transmit the scramble information will be described.

FIG. 8 is a block diagram showing the configuration of the base station apparatus according to Embodiment 3 of the present invention. In the base station apparatus of FIG. 8, the same components as those of FIG. 1 are assigned the same reference numerals as those of FIG. 1 and their explanations are omitted. Compared to FIG. 1, the base station apparatus shown in FIG. 8 has a scramble information generation unit 105.
The scramble code selection unit 103 is configured by removing the
Does not output scramble information anywhere.

The S / P conversion unit 106 converts the output signal of the scramble code multiplication unit 104, which is a serial data sequence, into a parallel data sequence (multicarrier modulation), and puts the data on all the subcarriers to be used. For example, if the number of subcarriers used is 100, all 100 subcarriers are used to carry data.

FIG. 9 is a block diagram showing the structure of the communication terminal apparatus according to Embodiment 3 of the present invention. In the communication terminal device of FIG. 9, the same components as those in FIG. 4 are assigned the same reference numerals as those in FIG. 4 and their explanations are omitted. Compared to FIG. 4, the communication terminal apparatus shown in FIG. 9 has a configuration in which scramble information extraction section 405 is deleted, output signal selection section 901 is added instead, and scramble restoration section 406 and despreading section 407 are provided in plurality. Take.

The P / S conversion unit 404 converts the output signal of the FFT unit 403, which is a parallel data sequence, into a serial data sequence, and scrambles the data to descrambling units 406-1 to 406-.
output to m.

Each scramble restoration section 406-1 to 406
-M is _{one of} the scramble codes {C ₁ , C ₂ , ... C _m } stored in the scramble code selecting section 103 of the base station apparatus, and the P / S converting section 40 selects different ones.
The signals input from 4 are multiplied and output to the corresponding despreading units 407-1 to 407-m.

The despreading units 407-1 to 407-m multiply the output signals of the corresponding scramble decompression units 406-1 to 406-m by the same user-specific spreading code as the base station apparatus and output the output signals. It is output to the selection unit 901.

The output signal selecting section 901 is provided for each despreading section 40.
Among the output signals of 7-1 to 407-m, the one with the highest power is output as data.

As described above, according to the present embodiment, the transmitting apparatus repeats the process of multiplying the generated scramble code by the spread multiplexed signal until the peak power becomes equal to or less than the threshold value, thereby making it non-linear. The peak power can be suppressed without performing any processing. In addition, the receiving device multiplies the received data by all scrambling codes and selects the one with the highest power of the despread data, so that the receiving device receives the scramble information even if it does not send the scramble information. Since the device can retrieve the data, transmission can be performed more efficiently than in the first and second embodiments, and the configuration of the transmission device can be simplified.

In the present embodiment, a case has been described in which a plurality of scrambling codes are prepared and sequentially selected in the base station apparatus as in the first embodiment, but the same scrambling code is used in the base station apparatus as in the second embodiment. 1
The same effect can be obtained even when the chip is cut out and subjected to the circulation process of attaching the chip to the rear end.

Further, in each of the above embodiments, the OFDM modulation method has been described as an example of the multi-carrier modulation method, but the present invention can be implemented in any multi-carrier modulation method.

In each of the above embodiments, the case where the base station device transmits data and the communication terminal device receives the data has been described. However, the present invention, the communication terminal device transmits data and the base station It is also applicable when the device receives data.

[0084]

As described above, according to the present invention,
In MC-CDMA wireless communication, peak power can be suppressed without performing non-linear processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a base station apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a scramble code selection unit and a scramble code multiplication unit of the base station apparatus according to the above embodiment.

FIG. 3 is a flowchart showing a scrambling code selection procedure of the base station apparatus according to the above embodiment.

FIG. 4 is a block diagram showing a configuration of a communication terminal device according to the above embodiment.

FIG. 5 is a block diagram showing the configuration of a base station apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a diagram for explaining a scrambling code generation method of a scrambling code generation unit of the base station apparatus according to the above embodiment.

FIG. 7 is a flowchart showing a scramble code generating procedure of the base station apparatus according to the above embodiment.

FIG. 8 is a block diagram showing a configuration of a base station apparatus according to Embodiment 3 of the present invention.

FIG. 9 is a block diagram showing a configuration of a communication terminal device according to the above embodiment.

FIG. 10 is a schematic diagram showing a state of digital symbols before modulation processing.

FIG. 11 is a schematic diagram showing an arrangement of chips in a conventional frequency domain spreading method.

FIG. 12 is a signal pattern diagram of an OFDM symbol in a conventional frequency domain spreading method.

[Explanation of symbols]

101 diffusion unit 102 multiplexing unit 103 scramble code selection unit 104 scramble code multiplication unit 105 scramble information generator 106 S / P (serial / parallel) converter 107 IFFT (Inverse Fourier Transform) Unit 108 Amplitude measuring section 403 FFT (Fourier transform) unit 404 P / S (parallel / serial) converter 405 Scramble information extraction unit 406 Scramble restoration unit 407 despreading unit 501 scramble code generator 901 Output signal selector

Claims (15)

[Claims] 1. A scramble code setting means for setting a scramble code, a scramble code multiplying means for multiplying a spread-multiplexed signal by the set scramble code, and a multi-carrier modulation processing for the signal multiplied by the scramble code. The scrambler further comprises: a multicarrier modulation means for performing the above, and an amplitude measurement means for measuring the peak power of the multicarrier-modulated signal and determining whether or not the measured peak power exceeds a preset threshold value. The code setting means sets a scramble code based on the determination result of the amplitude measuring means. 2. A scramble code setting means selects one from a plurality of held scramble codes, and when the peak power of a signal multiplied by the selected scramble code is larger than a threshold value, another scramble code is set. The transmitter according to claim 1, wherein the transmitter is selected. 3. The scramble code setting means, when the peak power of the signal multiplied by the scramble code is larger than a threshold value, cuts out a predetermined amount of chips from the head of the scramble code and attaches the chip to the rear end to obtain a new scramble code. The transmission device according to claim 1, wherein the transmission device is generated. 4. The transmission device according to claim 2, wherein the scramble code setting means transmits scramble information representing the scramble code selected by the scramble code setting means to a receiving device of a communication partner. 5. The transmission device according to claim 3, wherein the scramble code representing the number of the first chip of the scramble code generated by the scramble code setting means is transmitted to the receiving device of the communication partner. 6. A multicarrier demodulation means for performing multicarrier demodulation processing on a signal transmitted from the transmitting device according to claim 4 or 5, and scramble information is extracted from the signal transmitted from the transmitting device. Extraction means,
The scramble restoration means for multiplying the scramble code represented by the extracted scramble information by the multicarrier demodulated signal to restore the spread-multiplexed signal, and the despreading means for despreading the restored spread-multiplexed signal and extracting the data. A receiver, comprising: 7. Multi-carrier demodulation means for performing multi-carrier demodulation processing on the signal transmitted from the transmission device according to claim 1, and for the signal subjected to multi-carrier demodulation processing. The scramble restoration unit that multiplies the scramble code that may have been multiplied by the transmission device, the despreading unit that despreads each signal that has been multiplied by the scramble code, and the power that has the highest power among the despread signals. A receiving device, comprising: a selecting unit for extracting a large one as data. 8. A base station apparatus comprising the transmitting apparatus according to claim 1. Description: 9. A communication terminal device comprising the transmitting device according to claim 1. Description: 10. A base station apparatus comprising the receiving apparatus according to claim 6 or 7. 11. A communication terminal device, comprising the receiving device according to claim 6 or 7. 12. A radio communication method, wherein a transmitter sets a scramble code in which a peak power of a multicarrier-modulated signal is equal to or less than a preset threshold value and multiplies the spread-multiplexed signal by the scramble code. 13. A transmitter performs a first step of multiplying a spread-multiplexed signal by a scrambling code to perform a multi-carrier modulation process, and a second step of measuring a peak power of the multi-carrier modulated signal, If the peak power is higher than a preset threshold value, the scrambling code is changed and the first step and the second step are performed again, and if the peak power is less than or equal to the threshold value, a signal after the second step is sent to the receiving device. Is wirelessly transmitted to a receiving device. 14. A transmission device transmits scramble information representing a multiplied scramble code to a reception device, and the reception device performs multicarrier demodulation processing on a signal transmitted from the transmission device, and the transmission device. The scramble information is extracted from the signal transmitted from the signal, the scramble code represented by the extracted scramble information is multiplied by the signal subjected to the multi-carrier demodulation processing to restore the spread-spectrum multiplexed signal, and the restored spread-spectrum multiplexed signal is despread. 14. The wireless communication method according to claim 13, wherein the data is taken out. 15. A reception device performs multicarrier demodulation processing on a signal transmitted from a transmission device, and a scramble code that may have been multiplied by the transmission device on the signal subjected to multicarrier demodulation processing. Multiply each, despread each signal multiplied by the scramble code,
14. The wireless communication method according to claim 13, wherein the despread signal having the highest power is extracted as data.