JP2002190788A - Radio communication equipment and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both of a frequency diversity effect and a pass diversity effect and to improve a transmission characteristic as compared with a conventional method in radio communication combining a multi-carrier modulation system and a CDMA(code division multiple access) system. SOLUTION: When time area diffusers 102-1 to 102-N diffuse parallel data converted by an S/P(serial/parallel) conversion part 101 in a time base direction and a rearrangement part 103 shifts diffused chips stepwise in the ascending or descending direction of carrier frequency bands and rearranges the chips on a frequency axis, thus a certain data is distributed into the frequency axis and the time base and two-dimensionally arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication apparatus and a radio communication method used for a digital communication system, and more particularly to an OFDM (Orthogonal Frequency Divisio).
The present invention relates to a wireless communication apparatus and a wireless communication method for performing wireless communication by combining a multicarrier modulation method such as an n Multiplexing modulation method and a CDMA (Code Division Multiple Access) method.

[0002]

2. Description of the Related Art In recent years, in wireless communication, particularly in mobile communication,
Various types of information such as images and data other than audio are transmitted. In the future, since demand for transmission of various contents is expected to increase more and more, the need for reliable and high-speed transmission will further increase. However, when performing high-speed transmission in mobile communication, the effects of delayed waves due to multipath cannot be ignored, and transmission characteristics deteriorate due to frequency-selective fading.

As one of the frequency selective fading countermeasures, a multi-carrier modulation scheme such as an OFDM modulation scheme has attracted attention. The multicarrier modulation scheme is a technique for transmitting data at high speed by transmitting data using a plurality of carriers (subcarriers) whose transmission speed is suppressed to the extent that frequency selective fading does not occur. In particular, the OFDM modulation scheme is the scheme having the highest frequency use efficiency among the multi-carrier modulation schemes because a plurality of subcarriers on which data are arranged are orthogonal to each other. In addition, the OFDM modulation method can be realized with a relatively simple hardware configuration. from these things,
Various studies have been made on the OFDM modulation method as a measure against frequency selective fading.

[0004] As another technique for coping with frequency selective fading, there is a spread spectrum method. The spread spectrum method is a method in which a signal is spread on a frequency axis by a spread code called a PN code, and a spread gain is obtained to improve interference resistance. The spread spectrum method includes a direct spread method and a frequency hopping method. Above all, CDMA (Code Divisio
n Multiple Access) has been decided to be adopted in IMT-2000, which is the next generation of mobile communication.

[0005] An OFDM-CDMA system that combines the OFDM modulation system and the CDMA system has recently attracted attention. The OFDM-CDMA scheme is roughly classified into a time domain spreading scheme and a frequency domain spreading scheme. Less than,
The time domain spreading method and the frequency domain spreading method will be described.

First, the time domain spreading method will be described. FIG. 20 is a schematic diagram showing a state of digital symbols before modulation processing, and FIG. 21 is a schematic diagram showing an arrangement of each chip after modulation processing in the time domain spreading method. In the time domain spreading method, after N digital symbols (FIG. 20), which are serial data sequences, are converted into parallel data sequences, each digital symbol is multiplied by a spreading code with a spreading factor M. The inversed Fourier transform (IFFT) processing is sequentially performed on the chips after the diffusion, N chips in parallel one chip at a time. As a result, the OFDM symbol of N subcarriers is M
Are generated. That is, in the time domain spreading method, chips after spreading are arranged in time series in each subcarrier (FIG. 21).

[0007] Assuming that one digital symbol before the modulation processing uses radio resources having a time width T and a frequency bandwidth B (FIG. 20), after the modulation processing, one chip has a time width N × T / M and a frequency bandwidth N × T / M. The bandwidth M × B / N will be used. Therefore, the area per digital symbol in the time-frequency domain is M × T × B, which is M times the area occupied by one digital symbol before modulation processing.

Here, for example, the number of digital symbols N
= 8 and the spreading factor M = 8, the signal pattern of the OFDM symbol generated by the time domain spreading method is as shown in FIG.
As shown in FIG. As shown in this figure, in the time domain spreading method, eight digital symbols distinguished by black and white shading on the frequency axis have different subcarriers f1.
To f8, one chip at a time.
Generates eight OFDM symbols.

Next, the frequency domain spreading method will be described. FIG. 23 is a schematic diagram showing the arrangement of each chip after the modulation processing in the frequency domain spreading method. In the frequency domain spreading method, N digital symbols (FIG. 20), which are serial data sequences, are multiplied by a spreading code having a spreading factor M for each symbol. After spreading, M chips are subjected to IFFT processing sequentially in parallel, 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 spread chips are arranged on the frequency axis at each time (see FIG. 2).
3). In other words, the spread chips are arranged on different subcarriers.

Similarly, assuming that one digital symbol before the modulation process uses radio resources having a time width T and a frequency bandwidth B (FIG. 20), after the modulation process, one chip has a time width N × T, The frequency bandwidth B / N will be used. Therefore, the area per digital symbol in the time-frequency domain is M × T × B, as in the time domain spreading method, and is M times the area occupied by one digital symbol before modulation processing.

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

By using the time-domain spreading method or the frequency-domain spreading method as described above, efficient reuse can be realized and a statistical multiplexing effect can be obtained. In addition, data transmission at a higher speed than single-carrier CDMA can be realized. Note that “reuse” means that the same frequency can be used in adjacent cells. In addition, the statistical multiplexing effect means that, when data is randomly generated by a user, energy can be reduced in a non-transmitting section to accommodate more user signals than in the case of continuous transmission.

[0013]

However, in the time domain spreading method, when attention is paid to a certain digital symbol, a plurality of spread chips are arranged in time series at the same frequency (see FIG. 21 and FIG. 21). FIG.
2) Multipath separation is possible and a path diversity effect can be obtained, but a frequency diversity effect cannot be obtained.

[0014] For this reason, when the transmission power control according to the radio channel condition becomes incomplete, the transmission characteristics are greatly deteriorated. Further, even when the transmission power control is completely performed, an increase in the transmission power caused by this causes problems such as an increase in battery consumption of the mobile station device, an increase in the size of the amplifier, and an increase in the amount of interference with other cells.

Further, in the frequency domain spreading method, when attention is paid to a certain digital symbol, a plurality of spread chips are arranged on different subcarriers at the same time (FIGS. 23 and 24). Although the frequency diversity effect can be obtained, the path separation becomes impossible and the path diversity effect cannot be obtained.

[0016] Therefore, since RAKE combining cannot be performed, multipath distortion cannot be reduced. Further, when code division multiplexing is performed on signals of a plurality of users on each subcarrier, even if orthogonal codes are used for spreading processing, orthogonality cannot be maintained due to the influence of multipath distortion, so that the number of code division multiplexes is limited. . Further, the influence of the shift of the signal extraction timing at the time of the Fourier transform increases.

The present invention has been made in view of such a point, and in a wireless communication combining a multicarrier modulation system and a CDMA system, both a frequency diversity effect and a path diversity effect can be obtained. An object of the present invention is to provide a wireless communication device and a wireless communication method capable of improving transmission characteristics.

[0018]

A radio communication apparatus according to the present invention is a radio communication apparatus for performing communication by combining a multi-carrier modulation system and a CDMA system. A configuration including an arrangement unit that arranges two-dimensionally on both the axis and the time axis, and a transmission unit that transmits a multicarrier signal in which the divided data is assigned to the corresponding carrier is adopted.

A wireless communication apparatus according to the present invention is a wireless communication apparatus for performing communication by combining a multicarrier modulation method and a CDMA method, and includes a receiving means for receiving a multicarrier signal, and a communication partner which is divided into chip units. Means for returning the data two-dimensionally arranged on both the frequency axis and the time axis to the state before division.

In the radio communication apparatus according to the present invention, the arranging means arranges the spread chips in a stepwise manner in the direction of increasing or decreasing the carrier frequency on the frequency axis after spreading the data on the time axis. Use a configuration for conversion.

The wireless communication apparatus according to the present invention employs a configuration in which the return means returns each chip to the layout before the layout change in the communication partner, and then despreads the data whose layout has been returned on the time axis. .

The radio communication apparatus of the present invention employs a configuration in which the arranging means spreads data on both the time axis and the frequency axis.

The radio communication apparatus of the present invention employs a configuration in which the return means despreads data on both the time axis and the frequency axis.

According to these configurations, since a plurality of components having different frequencies are included, a frequency diversity effect can be obtained. Further, since a plurality of components having different times are included at the same time, a path diversity effect can be obtained.

In the radio communication apparatus according to the present invention, after the arranging means spreads the data on both the time axis and the frequency axis,
A configuration is adopted in which the spread of each chip is shifted stepwise in the direction of increasing or decreasing the carrier frequency on the frequency axis, and the arrangement is changed.

In the wireless communication apparatus according to the present invention, after the return means returns each chip to the layout before the layout change in the communication partner, the return data of each chip is returned on both the time axis and the frequency axis. Adopt a configuration that performs reverse diffusion.

According to these configurations, after spreading the data on both the time axis and the frequency axis, the spread chips are rearranged on the frequency axis to further enhance the frequency diversity effect. Can be.

The radio communication apparatus according to the present invention has a configuration in which the arranging means rearranges the chips in which the spread chips are arranged irregularly on the frequency axis and the time axis after the data is spread. take.

In the radio communication apparatus according to the present invention, the return means returns the chips arranged irregularly on the frequency axis and the time axis to the arrangement before rearrangement in the communication partner, and then returns the chips. A configuration is adopted in which the data whose arrangement has been returned is despread.

According to these configurations, each chip after spreading is arranged irregularly on both the frequency axis and the time axis, so that both the frequency diversity effect and the path diversity effect can be further enhanced.

The radio communication apparatus of the present invention employs a configuration including a thinning-out means for thinning out data after division allocated to a carrier having a poor line quality.

According to this configuration, no signal is transmitted on a carrier having poor line quality, so that when signals of a plurality of users are code-division multiplexed on each carrier, interference with other users can be reduced.

The communication terminal device of the present invention employs a configuration in which any of the above wireless communication devices is mounted. Further, the base station apparatus of the present invention employs a configuration in which any of the above wireless communication apparatuses is mounted.

According to these configurations, the same effects as described above can be obtained in the communication terminal apparatus and the base station apparatus.

The radio communication method according to the present invention is a radio communication method combining a multi-carrier modulation scheme and a CDMA scheme. On the transmission side, one piece of data is divided into chip units and divided on a frequency axis and a time axis. After two-dimensionally arranging the data on both sides, a multi-carrier signal in which the divided data is assigned to the corresponding carrier is transmitted, the multi-carrier signal is received on the receiving side, and
Dimensionally arranged data is returned to the state before division.

According to the radio communication method of the present invention, on the transmitting side, after spreading data on the time axis, the spread chips are arranged in a stepwise manner in the direction of increasing or decreasing the carrier frequency on the frequency axis. After the conversion, the receiving side returns each chip to the arrangement before the arrangement conversion on the transmitting side, and then despreads the data whose arrangement of each chip has been returned on the time axis.

The radio communication method of the present invention is such that data is spread on both the time axis and the frequency axis on the transmitting side, and the data is despread on the time axis and the frequency axis on the receiving side. I made it.

According to these methods, since a plurality of components having different frequencies are included, a frequency diversity effect can be obtained. Further, since a plurality of components having different times are included at the same time, a path diversity effect can be obtained.

According to the radio communication method of the present invention, on the transmitting side, after spreading data on both the time axis and the frequency axis, each spread chip is stepped up or down in the carrier frequency on the frequency axis. And shift the position,
On the receiving side, after returning each chip to the arrangement before the arrangement conversion on the transmitting side, the data obtained by returning the arrangement of each chip is despread on both the time axis and the frequency axis.

According to this method, after the data is spread on both the time axis and the frequency axis, the spread chips are rearranged on the frequency axis to further enhance the frequency diversity effect. it can.

According to the radio communication method of the present invention, after the data is spread on the transmitting side, the chips after the spreading are rearranged to arrange the chips irregularly on the frequency axis and the time axis, and the reception is performed. After returning each chip to the arrangement before rearrangement on the transmitting side, the data on the arrangement of each chip is despread.

According to this method, the chips after spreading are arranged irregularly on both the frequency axis and the time axis, so that both the frequency diversity effect and the path diversity effect can be further enhanced.

In the radio communication method according to the present invention, on the transmitting side, data after division, which is allocated to a carrier having a poor line quality, is thinned out.

According to this method, no signal is transmitted on a carrier having a poor line quality. Therefore, when code division multiplexing is performed on signals of a plurality of users on each carrier, interference with other users can be reduced.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is that, in wireless communication combining a multicarrier modulation system and a CDMA system, a plurality of chips after a certain digital symbol is spread on a conventional frequency axis or time axis. What is arranged one-dimensionally on one side is two-dimensionally arranged by distributing it on both the frequency axis and the time axis. This makes it possible to obtain both the frequency diversity effect and the path diversity effect in wireless communication combining the multicarrier modulation scheme and the CDMA scheme.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, an OFDM modulation scheme will be described as an example of a multicarrier modulation scheme. That is, a case where the transmitted multicarrier signal is an OFDM symbol will be described.

(Embodiment 1) In the present embodiment, data is spread on the time axis, and each spread chip is shifted stepwise in the direction of increasing or decreasing the carrier frequency on the frequency axis. By doing so, one piece of data is distributed on both the frequency axis and the time axis and arranged two-dimensionally.

FIG. 1 is a block diagram showing a configuration of a transmitting side in a radio communication apparatus according to Embodiment 1 of the present invention. 1 includes a serial / parallel conversion unit (S / P unit) 101, time domain spreaders 102-1 to 102-N, a rearrangement unit 103, and an inverse Fourier transform unit. (IFFT unit) 104 and wireless transmission unit 1
05 and an antenna 106.

FIG. 2 is a block diagram showing a configuration on the receiving side of the radio communication apparatus according to Embodiment 1 of the present invention. 2 includes an antenna 201, a radio reception unit 202, a Fourier transform unit (FFT unit) 203, an arrangement return unit 204, and time domain despreaders 205-1 to 205-. N and RAKE unit 206
-1 to 206-N and a parallel / serial conversion unit (P /
S section 207).

In the following description, a case will be described where N digital symbols are transmitted in parallel. Therefore, the wireless communication device shown in FIG. 1 has N time domain spreaders, and the wireless communication device shown in FIG. 2 also has N time domain despreaders and N RAKE units.

First, in the transmitting side radio communication apparatus shown in FIG. 1, in S / P section 101, N digital symbols 1 to N, which are serial data sequences as shown in FIG. 20, are converted into parallel data sequences. Are input to the corresponding time domain spreaders. That is, digital symbol 1
Are time domain spreaders 102-1 and digital symbols 2 are time domain spreaders 102-2,.
Are input to the time domain spreaders 102-N, respectively.

In time domain spreaders 102-1 to 102-N, digital symbols 1 to N are spread with a spreading code having a spreading factor M. That is, digital symbols 1 to N
Is spread over the M chips on the time axis. Specifically, the digital symbol 1 in the time domain spreader 102-1 is used.
Is spread to chips at time t0 to tM, and digital symbol 2 is
Spread into time chips,..., Time domain spreader 102-
At N, the digital symbol N is spread to chips at time t0 to tM. The data for M chips after the spreading is input to the rearrangement unit 103. Therefore, the rearrangement unit 10
3, the data of the chip arrangement as shown in FIG. 21 is stored. That is, data for N symbols in the frequency axis direction and data for M chips in the time axis direction are stored.

The rearrangement unit 103 rearranges the spread chips by shifting the spread chips stepwise on the frequency axis in the direction of increasing or decreasing the carrier frequency. Here, a case will be described in which the digital symbol 1 is focused on and the carrier frequency is shifted in the increasing direction. That is, the chips 1 to M of the digital symbol 1 spread in the time axis direction are shifted one step at a time in the ascending direction of the carrier frequency as shown in FIG. Such a shift process is performed on the chips 1 to M of the digital symbols 1 to N.

Each of the rearranged chips is sequentially input to the IFFT unit 104 in parallel in N pieces and subjected to IFFT processing. As a result of the IFFT processing after the rearrangement is performed, first, chip 1 of digital symbol 1 is placed on subcarrier 1, chip 1 of digital symbol 2 is placed on subcarrier 2,. OFDM symbol to which chip 1 is assigned is generated. Next, chip 2 of digital symbol N is assigned to subcarrier 1, and digital symbol 1 is assigned to subcarrier 2.
,..., And subcarriers N are assigned with chip 2 of digital symbol N−1, respectively, to generate an OFDM symbol. Such an OFDM symbol is M
Are generated. In other words, one certain digital symbol is allocated two-dimensionally on both the frequency axis and the time axis.

Here, for example, the number of digital symbols N
= 8 and the spreading factor M = 8, the signal pattern of the OFDM symbol generated by IFFT section 104 is as shown in FIG. As shown in this figure, in the present embodiment,
Eight digital symbols that are distinguished by black and white shading are different subcarriers f1 to f8 over time.
Are sequentially allocated one chip at a time, and eight OFDM symbols are generated at t0 to t7. That is, the eight chips obtained by spreading the digital symbol 1 are time t0 of the frequency f1, time t1 of the frequency f2, and
3, time t3 of frequency f4, and frequency f5
At time t4, time t5 at frequency f6, time t6 at frequency f7, and time t7 at frequency f8.

Similarly, the chips of the digital symbols 2 to 8 are also arranged stepwise in front of the digital symbol 1. For example, each chip of the digital symbol 2 has a time t0 of the frequency f2 and a time t0 of the frequency f3.
1, time t2 at frequency f4, and time t3 at frequency f5
And time t4 of frequency f6 and time t5 of frequency f7
And time t6 at frequency f8.

As shown in FIG. 3, one chip uses a time width N × T / M and a frequency bandwidth M × B / N. That is, the interval between subcarriers of the OFDM symbol shown in FIG. 4 is M × B / N. Therefore, the area per digital symbol in the time-frequency domain is M × T × B, which is M times the area occupied by one digital symbol before modulation processing.

M OFFs generated by IFFT section 104
The DM symbols are sequentially input to the wireless transmission section 105, subjected to predetermined wireless processing such as up-conversion, and then transmitted from the antenna 106.

In the wireless communication apparatus on the receiving side shown in FIG. 2, the wireless receiving section 202 performs predetermined wireless processing such as down-conversion on the OFDM symbol received via the antenna 201. OFDM after radio processing
The symbols are input to FFT section 203. And O
By performing FFT processing on the FDM symbols in the FFT section 203, signals of digital symbols 1 to N transmitted by the subcarriers 1 to N are extracted.
A similar process is performed on the M OFDM symbols that are sequentially received, and the result is input to arrangement return section 204.

In arrangement rearranging section 204, the reverse arrangement conversion corresponding to the arrangement conversion performed in arrangement rearranging section 103 of the radio communication apparatus on the transmitting side is performed. As a result, the data arrangement of each chip is returned to the same arrangement as before the arrangement change by the rearrangement unit 103. That is, the data arrangement of each chip is
It is returned to the arrangement shown in FIG. After the arrangement is returned, each of the chips is time-domain despreaders 205-1 to 205-2 in parallel.
05-N and despread. The despread data is input to RAKE sections 206-1 to 206-N, respectively.

In the RAKE units 206-1 to 206-N,
RA that rakes and combines delay path components along the time axis
KE combining processing is performed. That is, the RAKE unit 206
-1, the RAKE combining is performed on the digital symbol 1, the RAKE unit 206-2 performs the RAKE combining on the digital symbol 2,.
In 6-N, RAKE combining is performed on the digital symbol N. Each of the digital symbols after RAKE combining is input to P / S section 207.

In the P / S unit 207, the RAKE unit 206-
Digital symbols 1 to N input in parallel from 1 to 206-N are converted into serial data series and output.
Thus, the RAKE-combined digital symbol 1
To N are sequentially obtained.

As described above, in the present embodiment, on the transmitting side, data (digital symbols) allocated to a plurality of subcarriers having different frequencies by S / P conversion are spread in the direction of elapse of time. After the subsequent chips are shifted and shifted in a stepwise manner in the carrier frequency ascending or descending direction on the frequency axis, the OFDM symbols are generated by IFFT processing. Also, on the receiving side, the data after the FFT processing is returned to the arrangement before the arrangement conversion on the transmitting side, and the returned data is despread in the direction of elapse of time.

Thus, each data after despreading has
A plurality of components having different frequencies and times will be included. Thus, since a plurality of components having different frequencies are included, a frequency diversity effect can be obtained. Further, since a plurality of components having different times are included at the same time, OFD
Multipath separation can be performed with the accuracy of M symbols, and thus RAKE combining can be performed, so that multipath distortion can be reduced. That is, a path diversity effect is obtained. Also, since orthogonality can be maintained when orthogonal codes are used in the spreading process, the number of code division multiplexing can be increased. Further, it is possible to suppress the influence of the shift of the signal extraction timing at the time of the Fourier transform.

Further, high-speed transmission power control becomes unnecessary, and the accuracy and reflection time of the transmission power control can be reduced. As a result, it is possible to alleviate the conventional problem, that is, a drastic increase in characteristic deterioration when transmission power control becomes incomplete. In addition, it is possible to mitigate an increase in power consumption of the battery of the mobile station apparatus, an increase in the size of the amplifier, and an increase in the amount of interference with other cells due to an increase in transmission power due to transmission power control.

In this embodiment, one digital symbol is shifted on the frequency axis by shifting each chip spread on the time axis in a stepwise manner in the direction of increasing or decreasing the carrier frequency on the frequency axis. And on the time axis to be arranged two-dimensionally.
However, in the present embodiment, the method of distribution on the frequency axis is not limited to this, and any method of distribution on the frequency axis based on a predetermined rule may be used.

(Embodiment 2) In this embodiment, data is spread in both the frequency domain and the time domain, that is,
By spreading in both the frequency axis direction and the time axis direction, one piece of data is distributed two-dimensionally on both the frequency axis and the time axis.

FIG. 5 is a block diagram showing a configuration on the transmitting side in a radio communication apparatus according to Embodiment 2 of the present invention. The transmitting wireless communication apparatus shown in FIG. 5, the frequency domain spreader 301, an S / P section 101, a time domain spreader 102-1 to 102-M _1, an IFFT unit 104, radio transmission section 105 And an antenna 106. In FIG. 5, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

FIG. 6 is a block diagram showing a configuration on the receiving side of the radio communication apparatus according to Embodiment 2 of the present invention. 6 includes an antenna 201, a radio receiving unit 202, and an FFT unit 203.
When a time domain despreaders 205-1 to 205-M _1, R
And AKE part 206-1~206-M _1, P / S section 207
And a frequency domain despreader 401.
6, the same components as those in the first embodiment (FIG. 2) are denoted by the same reference numerals as those in FIG. 2, and detailed description is omitted.

In the following description, a case will be described in which each of the digital symbols 1 to N is spread at a spreading factor M ₁ on the frequency axis. Therefore, the wireless communication apparatus shown in FIG. 5 includes M ₁ time domain spreaders, and the wireless communication apparatus shown in FIG.
M ₁ parts are also provided.

First, in the radio communication apparatus on the transmitting side shown in FIG. 5, frequency domain spreader 301 uses N digital symbols 1 as a serial data sequence as shown in FIG.
~N sequentially, is spread with a first spreading code of spreading factor M _1.
The data for M ₁ chips after the spreading is input to the S / P section 101. In S / P section 101, M ₁ input in series
Data for the chip is converted in parallel. By these processes, it is diffused into M ₁ chip digital symbol 1~N is on the frequency axis, resulting in that each chip of 1 to M ₁ is allocated to subcarriers 1 to M ₁ of different frequencies .

The M ₁ chips converted in parallel by S / P section 101 are input to corresponding time domain spreaders. That is, the first chip time domain spreader 102-1,2 th chip time domain spreader 102-2 of each digital symbol, ..., M ₁ th chip time domain spreader 10
It is input to the 2-M _1.

Time domain spreaders 102-1 to 102-M ₁
In the chip 1 to M ₁ is further diffused by the second spreading code of spreading factor M _2. That is, the digital symbol spread on M ₁ chips on the frequency axis is further spread on M ₂ chips on the time axis. In other words, each digital symbol, M ₁ times in the frequency domain, M ₂ in the time domain
It is spread to twice M ₁ × M ₂ times. As a result, one digital symbol is distributed two-dimensionally on both the frequency axis and the time axis.
Each chip is spread in the time domain spreader 102-1 to 102-M ₁ is inputted to the M ₁ piece parallel and sequentially IFFT section 104 and subjected to IFFT processing. As a result, IFFT
Unit 104 generates N × M ₂ OFDM symbols.

Here, for example, the spreading factor M in the frequency domain
_{When 1} = 4 and the spreading factor in the time domain M ₂ = 2, the arrangement of each chip on the frequency axis and the time axis is as shown in FIG. That is, the digital symbols 1 to N are sequentially arranged for four chips in the frequency axis direction and two chips in the time axis direction.

The OFFT unit 104 generates the OF
The signal pattern of the DM symbol is as shown in FIG. That is, the eight chips obtained by spreading the digital symbol 1 are divided into the time t0 of the frequency f1 and the frequency f1.
2, time t0 of frequency f3, and time f0 of frequency f3.
At time t0, time t1 at frequency f1, time t1 at frequency f2, time t1 at frequency f3, and time t1 at frequency f4. Similarly, each chip of the digital symbols 2 to 8 is arranged behind the digital symbol 1. For example, digital symbol 2
Of the frequency f1, the time t2 of the frequency f2, the time t2 of the frequency f3, the time t2 of the frequency f4, the time t3 of the frequency f1, the time t3 of the frequency f2, and the time t3 of the frequency f3. Time t3 and time t of frequency f4
3 will be arranged.

As shown in FIG. 7, one chip uses a time width N × T / M ₂ and a frequency bandwidth M ₂ × B / N. That is, the interval between the subcarriers of the OFDM symbol shown in FIG. 8 is M ₂ × B / N. Therefore,
The area per digital symbol in the time-frequency domain is M ₁ × M ₂ × T × B, which is M ₁ × M ₂ times the area occupied by one digital symbol before modulation processing. If M ₁ × M ₂ = M, the spreading factor in the present embodiment is M times as in the first embodiment.

In the wireless communication apparatus on the receiving side shown in FIG.
Is input to Then, FF for the OFDM symbol
By performing the FFT processing in the T unit 203, the signals transmitted by the subcarriers ₁ to M1 are extracted.
Similar processing is performed on the N × M ₂ OFDM symbols that are sequentially received, and the time domain despreaders 205-1 to 205-1 are processed.
Is input to 205-M _1.

Time domain despreaders 205-1 to 205-M
_{In 1} , the time domain spreader 102 of the wireless communication device on the transmission side
In the same second spreading code as used in -1~102-M ₁ (spreading factor M _2), despreading processing is performed on the input data. That is, despreading processing is performed in the time domain. The despread data is stored in the RAKE section 206-
After in one to two hundred and six-M ₁ are respectively RAKE synthesis, P
The signal is converted into a serial data series by the / S unit 207 and input to the frequency domain despreader 401.

In the frequency domain despreader 401, the same first spreading code (spreading factor M ₁ ) as that used in the frequency domain spreader 301 of the radio communication apparatus on the transmitting side is used to inversely input data. A diffusion process is performed. As a result, RAK
E-combined digital symbols 1 to N are sequentially obtained.

In this embodiment, it is also possible to transmit X digital symbols in parallel. However, in this case, the wireless communication device on the transmitting side needs a time domain spreader, and the wireless communication device on the receiving side needs X × M ₁ time domain despreaders and RAKE units. That is, one OFDM symbol includes X × M ₁ subcarriers.

For example, when two digital symbols are transmitted in parallel, the S / P section of the radio communication apparatus on the transmitting side transmits digital symbols 1 each spread by M ₁ times.
And the chips of the digital symbol 2 are output in parallel. That is, 2 × M ₁ chips are output in parallel.
As a result, digital symbol 1 and digital symbol 2 are simultaneously spread on M ₁ chips on the frequency axis. Then, each chip is further spread to M ₂ chips on the time axis by the time domain spreader 102.

Thus, for example, the spreading factor M in the frequency domain
_{If 1} = 4 and the spreading factor in the time domain M ₂ = 2, the arrangement of each chip on the frequency axis and the time axis is as shown in FIG. That is, the digital symbols spread to 4 × 2 chips are arranged in parallel on the frequency axis by two digital symbols.

The OFFT unit 104 generates an OFF
The signal pattern of the DM symbol is as shown in FIG. That is, the eight chips obtained by spreading the digital symbol 1 are divided into the time t0 of the frequency f1 and the frequency f1 respectively.
2, time t0 of frequency f3, and time f0 of frequency f3.
At time t0, time t1 at frequency f5, time t1 at frequency f6, time t1 at frequency f7, and time t1 at frequency f8. Further, each chip of the digital symbol 2 includes a time t0 of the frequency f5, a time t0 of the frequency f6, a time t0 of the frequency f7, a time t0 of the frequency f8, a time t1 of the frequency f5, and a frequency f5.
6, time t1 of frequency f7, and frequency f8
At time t1.

As described above, in the present embodiment, after the data (digital symbols) are spread in both the frequency domain and the time domain on the transmitting side, the OFDM symbols are generated by IFFT processing. In addition, the receiving side performs despreading in both the frequency domain and the time domain in correspondence with the spreading process on the transmitting side. Thus, the same effect as in the first embodiment can be obtained.

In this embodiment, it is also possible to perform spreading in the time axis direction individually for each of the frequencies f1 to f8, or for each group by grouping for each of the near frequencies. For example, by spreading f1, f3, f5, and f7 as one group, and f2, f4, f6, and f8 as one group and performing spreading in the time axis direction for each group, for example, as shown in FIG. , Two of the same digital symbols continue in the time axis direction and are alternately arranged in the frequency axis direction. By doing so, the effect of reducing intersymbol interference when orthogonal codes are used for spreading can be maintained. Further, the frequency diversity effect increases as the frequency of the carrier on which the same digital symbol is arranged increases, and the effect of reducing intersymbol interference can increase as the frequency approaches.

In this embodiment, the spreading process in the time domain is performed after the spreading process in the frequency domain. However, this order may be reversed. That is, even if spread processing in the frequency domain is performed after spread processing in the time domain, one digital symbol can be two-dimensionally arranged by being distributed on both the frequency axis and the time axis. it can.

(Embodiment 3) In this embodiment, after data is spread in both the frequency domain and the time domain, each spread chip is stepped in the carrier frequency ascending or descending direction on the frequency axis. The layout is shifted and shifted.

FIG. 12 is a block diagram showing a configuration on the transmitting side in a radio communication apparatus according to Embodiment 3 of the present invention. The transmitting-side wireless communication apparatus shown in FIG. 12 is a time-domain spreader 1 of the wireless communication apparatus (FIG. 5) according to the second embodiment.
02-1 to 102-M ₁ and the IFFT unit 104,
The configuration further includes the rearrangement unit 103 described in the first embodiment. Note that in FIG.
The same components as those in FIG. 1 (FIG. 1) or Embodiment 2 (FIG. 5) are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 13 is a block diagram showing a configuration on the receiving side of the radio communication apparatus according to Embodiment 3 of the present invention. The wireless communication device on the receiving side shown in FIG.
FFT section 2 of wireless communication apparatus (FIG. 6) according to Embodiment 2
03 and the time domain despreaders 205-1 to 205 -M ₁ are further provided with the arrangement returning unit 204 described in the first embodiment. In FIG. 13, the same components as those in Embodiment 1 (FIG. 2) or Embodiment 2 (FIG. 6) are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the transmitting-side radio communication apparatus shown in FIG.
As described in the second embodiment, each digital symbol is spread in both the frequency domain and the time domain, and further, as described in the first embodiment, rearrangement section 103
, Each chip is rearranged.

For example, the spreading factor M ₁ = 2 in the frequency domain,
After performing spreading processing in both the frequency domain and the time domain with the spreading factor M ₂ = 4 in the time domain, the rearrangement unit 103
By performing the shift processing in the frequency axis direction (ascending direction) at, the signal pattern of the OFMD symbol becomes as shown in FIG. Here, a case is shown in which four digital symbols are transmitted in parallel.

Further, in the radio communication apparatus on the receiving side shown in FIG.
Then, after the arrangement is returned to the arrangement before the arrangement conversion by the arrangement rearrangement unit 103, it is despread in both the frequency domain and the time domain.

As described above, in the present embodiment, after spreading data in both the frequency domain and the time domain, each spread chip is subjected to layout conversion on the frequency axis. Thereby, the frequency diversity effect can be further enhanced as compared with the first or second embodiment.

(Embodiment 4) In the present embodiment, a certain
When two data are distributed two-dimensionally on both the frequency axis and the time axis, the spread chips are arranged irregularly both on the frequency axis and on the time axis.

FIG. 15 is a block diagram showing a configuration on the transmitting side in a radio communication apparatus according to Embodiment 4 of the present invention. 15 includes a spreader 501, a chip interleaving section 502, and an S / P section 1.
01, an IFFT unit 104, a wireless transmission unit 105, and an antenna 106. In FIG. 15, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

FIG. 16 is a block diagram showing a configuration on the receiving side of the radio communication apparatus according to Embodiment 4 of the present invention. The wireless communication device on the receiving side shown in FIG.
Antenna 201, radio receiving section 202, FFT section 20
3, the P / S unit 207, and the chip deinterleave unit 60
1 and a despreader 602. In FIG. 16, the same components as those in the first embodiment (FIG. 2) are denoted by the same reference numerals as those in FIG. 2, and detailed description is omitted.

In the radio communication apparatus on the transmitting side shown in FIG. 15, spreader 501 spreads N digital symbols 1 to N, which are serial data sequences, sequentially with a spreading code having a spreading factor M. The spread chips are sequentially input to the chip interleave section 502. As a result, N × M chips are stored in the chip interleave section 502.

In the chip interleave section 502, as shown in FIG. 17, for example, as shown in FIG. 17, the chip interleave has a predetermined pattern of chip interleaves (arrangement of chip sequences) arranged irregularly on the frequency axis and the time axis. Replacement) processing is performed. Thus, the M of one digital symbol
The chips are randomly arranged on the frequency axis and the time axis. Each chip after the chip interleave processing is S
/ P part and converted in parallel.

In the wireless communication device on the receiving side shown in FIG.
Each chip after the P / S conversion is converted to a chip deinterleave unit 60.
1 is input. In the chip deinterleave unit 601,
The reverse of the rearrangement performed by the chip interleaver 502 on the transmission side is performed. By this chip deinterleaving processing, the chip sequence is divided into the chip interleave unit 5
Return to the state before sorting by 02. Each chip after the chip deinterleaving processing is input to the despreader 602 and despread with the same spreading code (spreading factor M) used in the spreader 501 on the transmission side.

As described above, in this embodiment, chip interleaving is performed in which chips after spreading are arranged irregularly on the frequency axis and the time axis. Thereby, both the frequency diversity effect and the path diversity effect can be further enhanced as compared with the first or second embodiment.

By changing the interleave pattern for each sector, it is possible to reduce interference between adjacent sectors. Also, by changing the interleave pattern for each communication partner, the SIR (signal power to interference ratio) is averaged, and errors occurring in the transmission path can be further dispersed, so that the effect of error correction can be enhanced. it can.

(Embodiment 5) In this embodiment, the FDD
In a (Frequency Division Duplex) type communication system, an OFDM symbol is generated without assigning chip components to subcarriers having poor line quality.

FIG. 18 is a block diagram showing a configuration of a radio communication apparatus according to Embodiment 5 of the present invention. FIG.
In FIG. 8, the same components as those in the second embodiment (FIGS. 5 and 6) are denoted by the same reference numerals as those in FIG. 5 or FIG. 6, and detailed description is omitted.

The radio communication apparatus shown in FIG.
This is a wireless communication device used in a communication system of a system. A wireless communication device of a communication partner that communicates with the wireless communication device also has the same configuration.

In the radio communication apparatus shown in FIG. 18, the transmitting side further includes a multiplexing section 701, a chip thinning section 702, and insertion sections 703-1 to 703-M in addition to the configuration shown in FIG.
₁ is provided. In addition, the receiving side further includes channel estimating units 704-1 to 704-M ₁ in addition to the configuration shown in FIG.
And a separation unit 705.

In such a configuration, the OFDM symbol from the communication partner received on the receiving side is
After the FFT process in 3, for each sub-carrier component, is input to the channel estimation section 704-1~704-M _1. The channel estimation section 704-1~704-M _1, using a pilot signal inserted for each subcarrier, channel quality of each subcarrier is estimated. A pilot signal for performing channel estimation is transmitted on the transmitting side of the communication partner.
The insertion portion 703-1~703-M ₁ is inserted constant power pilot signals.

Here, in the FDD system, signals are transmitted and received using different frequency bands for the transmission line and the reception line, and therefore, it is necessary to determine how the signal transmitted by the own device reaches a communication partner. I can't know it on the device. Also,
The communication partner cannot know how the signal transmitted by the communication partner reaches its own device. Therefore, it is necessary to have the communication partners mutually inform the line estimation information.

Therefore, channel estimating units 704-1 to 704-
A value indicating the line quality of the receiving line estimated at M ₁ (for example, the amount of amplitude fluctuation or the amount of phase fluctuation) is input to multiplexing section 701 as line estimation information. Multiplexing section 701 multiplexes channel estimation information on digital symbols. As a result, the channel estimation information of the signal received by the own device is transmitted to the communication partner, and the communication partner can be informed of the channel quality (propagation path condition) of the signal transmitted by the communication partner.

On the receiving side, channel estimation information for each subcarrier transmitted from a communication partner is separated by separation section 705 and input to chip thinning section 702. In the chip thinning section 702, chip components of subcarriers having poor line quality are thinned according to the line estimation information of the transmission line. In other words, of the chips output from the frequency domain spreader 301, chip components assigned to subcarriers whose amplitude variation and phase variation are equal to or greater than a predetermined threshold are thinned out. Therefore, no signal is transmitted on subcarriers having poor line quality.

As described above, in the present embodiment, an OFDM symbol is generated in a FDD communication system without assigning chip components to subcarriers having poor line quality. That is, no signal is transmitted on subcarriers having poor line quality. This makes it possible to reduce interference with other users when code division multiplexing signals of a plurality of users on each subcarrier.

In the present embodiment, although the transmission characteristics are slightly degraded by thinning out the chip components, they can be sufficiently complemented by error correction codes or the like.

(Embodiment 6) This embodiment relates to a TDD
In a (Time Division Duplex) communication system, an OFDM symbol is generated without assigning chip components to subcarriers having poor line quality.

FIG. 19 is a block diagram showing a configuration of a radio communication apparatus according to Embodiment 6 of the present invention. FIG.
In FIG. 9, the same components as those of the fifth embodiment (FIG. 18) are denoted by the same reference numerals as those of FIG. 18, and detailed description is omitted.

The wireless communication apparatus shown in FIG.
This is a wireless communication device used in a communication system of a system. A wireless communication device of a communication partner that communicates with the wireless communication device also has the same configuration. The switch 801
, The antenna 802 and the wireless transmission unit 105 are connected during time slot transmission, and the antenna 802 and the wireless reception unit 202 are connected during time slot reception.

In the TDD system, unlike the FDD system, signals are transmitted and received on the transmission line and the reception line using the same frequency band. Therefore, when the time slot interval is sufficiently short and the line condition hardly changes between adjacent transmission / reception times, the line quality estimated on the receiving side can be used as the line quality on the transmitting side.

Therefore, channel estimating units 704-1 to 704-
A value indicating the line quality estimated at M ₁ (for example, the amount of amplitude fluctuation or the amount of phase fluctuation) is input to the chip thinning unit 702 as line estimation information. The chip decimation unit 702 uses this channel estimation information of the reception channel as channel estimation information of the transmission channel, and decimates the chip component of the subcarrier having poor channel quality. That is, the frequency domain spreader 301
Of the chips output from the sub-carriers, the chip components allocated to the subcarriers whose amplitude variation and phase variation are equal to or larger than predetermined thresholds are thinned out. Therefore, no signal is transmitted on subcarriers having poor line quality.

As a result, the same effect as in the fifth embodiment can be obtained in a TDD communication system. That is, when code from a plurality of users is code division multiplexed on each subcarrier, interference with other users can be reduced. Further, as in Embodiment 5, although the transmission characteristics are slightly deteriorated by thinning out the chip components, they can be sufficiently complemented by error correction codes or the like.

Note that Embodiments 5 and 6 can be implemented in combination with any of Embodiments 1 to 4.

In the first to sixth embodiments, the OFDM modulation method has been described as an example of the multicarrier modulation method, but the present invention can be implemented in any multicarrier modulation method.

The radio communication device according to the present invention can be mounted on a communication terminal device or a base station device in a digital communication system.

[0121]

As described above, according to the present invention,
In wireless communication combining a multicarrier modulation scheme and a CDMA scheme, both a frequency diversity effect and a path diversity effect can be obtained, and transmission characteristics can be made better than in the past.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmission side in a wireless communication apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a receiving side in the wireless communication apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a schematic diagram showing an arrangement of each chip in the wireless communication device according to the first embodiment of the present invention.

FIG. 4 is a signal pattern diagram of an OFDM symbol transmitted from the wireless communication apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a block diagram showing a configuration of a transmission side in a wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a block diagram showing a configuration of a receiving side in a wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 7 is a schematic diagram showing an arrangement of each chip in a wireless communication device according to a second embodiment of the present invention.

FIG. 8 is a signal pattern diagram of an OFDM symbol transmitted from a wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 9 is a schematic diagram showing an arrangement of each chip in the wireless communication device according to the second embodiment of the present invention.

FIG. 10 is a signal pattern diagram of an OFDM symbol transmitted from a wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 11 is a signal pattern diagram of an OFDM symbol transmitted from a wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 12 is a block diagram showing a configuration of a transmission side in a wireless communication apparatus according to Embodiment 3 of the present invention.

FIG. 13 is a block diagram showing a configuration on a receiving side in a wireless communication apparatus according to Embodiment 3 of the present invention.

FIG. 14 is a signal pattern diagram of an OFDM symbol transmitted from a wireless communication apparatus according to Embodiment 3 of the present invention.

FIG. 15 is a block diagram showing a configuration of a transmission side in a wireless communication apparatus according to Embodiment 4 of the present invention.

FIG. 16 is a block diagram showing a configuration on a receiving side in a wireless communication apparatus according to Embodiment 4 of the present invention.

FIG. 17 is a signal pattern diagram of an OFDM symbol transmitted from a wireless communication apparatus according to Embodiment 4 of the present invention.

FIG. 18 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 5 of the present invention.

FIG. 19 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 6 of the present invention.

FIG. 20 is a schematic diagram showing a state of a digital symbol before modulation processing;

FIG. 21 is a schematic diagram showing an arrangement of each chip in a conventional time domain spreading method.

FIG. 22 is a signal pattern diagram of an OFDM symbol in a conventional time domain spreading method.

FIG. 23 is a schematic diagram showing an arrangement of each chip in a conventional frequency domain spreading method.

FIG. 24 is a signal pattern diagram of an OFDM symbol in a conventional frequency domain spreading method.

[Explanation of symbols]

 Reference Signs List 101 S / P section 102 Time domain spreader 103 Rearrangement section 104 IFFT section 105 Wireless transmission section 202 Wireless reception section 203 FFT section 204 Rearrangement return section 205 Time domain despreader 206 RAKE section 207 P / S section 301 Frequency domain spread Demultiplexer 401 Frequency domain despreader 501 Spreader 502 Chip interleave section 601 Chip deinterleave section 602 Despreader 701 Multiplex section 702 Chip thinning section 703 Insertion section 704 Line estimation section 705 Separation section

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 DD01 DD21 DD31 EE01 EE21 EE31 FF01 5K059 AA08 CC06 EE02 5K067 AA02 AA33 CC02 CC10 CC24 HH21

Claims (19)

[Claims] 1. A wireless communication apparatus for performing communication by combining a multicarrier modulation method and a CDMA method, wherein one piece of data is divided into chips and two-dimensionally divided on both a frequency axis and a time axis. And a transmitting means for transmitting a multi-carrier signal in which the divided data is allocated to a corresponding carrier. 2. The arranging means, after spreading the data on the time axis, shifts the spread chips by stepwise shifting in the direction of increasing or decreasing the carrier frequency on the frequency axis. The wireless communication device according to claim 1, wherein 3. The radio communication apparatus according to claim 1, wherein the arranging means spreads the data on both the time axis and the frequency axis. 4. The arranging means, after spreading the data on both the time axis and the frequency axis, arranges the spread chips in a stepwise manner in the carrier frequency ascending or descending direction on the frequency axis. The wireless communication device according to claim 1, wherein the conversion is performed. 5. The arranging means, after spreading the data, rearranges the chips in which the spread chips are arranged irregularly on the frequency axis and on the time axis. The wireless communication device according to claim 1. 6. The wireless communication apparatus according to claim 1, further comprising a thinning-out unit for thinning out the divided data assigned to the carrier having a poor line quality. 7. A wireless communication apparatus for performing communication by combining a multicarrier modulation method and a CDMA method, comprising: a receiving means for receiving a multicarrier signal; A wireless communication device comprising: means for returning data arranged two-dimensionally on both axes to a state before division. 8. The method according to claim 7, wherein the return means returns each chip to the layout before the layout change in the communication partner, and then despreads the data whose layout has been returned on the time axis. Wireless communication device. 9. The method according to claim 7, wherein the return unit despreads the data on both the time axis and the frequency axis.
The wireless communication device according to claim 1. 10. The return means returns each chip to the layout before the layout change in the communication partner, and then despreads the data whose layout has been returned on both the time axis and the frequency axis. The wireless communication device according to claim 7, wherein 11. The return means returns each chip arranged irregularly on both the frequency axis and the time axis to the arrangement before rearrangement in the communication partner, and then returns the data obtained by returning the arrangement of each chip. The wireless communication device according to claim 7, wherein the wireless communication device performs despreading. 12. A communication terminal device comprising the wireless communication device according to claim 1. 13. A base station device comprising the wireless communication device according to claim 1. 14. A wireless communication method combining a multi-carrier modulation method and a CDMA method, wherein at a transmission side, one data is divided into chips and two-dimensionally divided on both a frequency axis and a time axis. After arranging the data, a multicarrier signal in which the divided data is assigned to the corresponding carrier is transmitted, the multicarrier signal is received on the receiving side, and the data arranged two-dimensionally on the transmitting side is divided before the division. A wireless communication method characterized by returning to a state. 15. On the transmitting side, after spreading the data on the time axis, the spread chips are stepwise shifted in the direction of increasing or decreasing the carrier frequency on the frequency axis, and are rearranged and converted. 15. The method according to claim 14, wherein after returning each chip to the arrangement before the arrangement conversion on the transmitting side, the data obtained by returning the arrangement of each chip is despread on the time axis.
The wireless communication method as described. 16. The transmitting side spreads data on both the time axis and the frequency axis, and the receiving side despreads data on both the time axis and the frequency axis. 15. The wireless communication method according to 14. 17. On the transmission side, after spreading data on both the time axis and the frequency axis, the spread chips are arranged in a stepwise manner in the carrier frequency ascending or descending direction on the frequency axis. After the conversion, on the receiving side, after returning each chip to the arrangement before the arrangement conversion on the transmitting side, the data obtained by returning the arrangement of each chip is despread on both the time axis and the frequency axis. The wireless communication method according to claim 14. 18. On the transmitting side, after spreading data, rearrangement of chips in which the spread chips are arranged irregularly on the frequency axis and the time axis is performed.
15. The wireless communication method according to claim 14, wherein, on the receiving side, each chip is returned to the arrangement before rearrangement on the transmission side, and then the data whose arrangement is returned is despread. 19. The wireless communication method according to claim 14, wherein the transmitting side thins out the divided data assigned to the carrier having the poor line quality.