Multi-carrier cdma wireless transmission method and system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a multicarrier CDMA (Code Division Multiple Access) wireless transmission method and apparatus, and more particularly to a multicarrier CDMA wireless transmission method and apparatus capable of transmitting information at various transmission rates.

【0002】

[Conventional technology]

Currently, digital mobile communication systems that provide communication services (PDC (Personal Digital Cellular), GSM (Global System for Mobile communications), etc.) use the TDMA (Time Division Multiple Access) method, which allocates time zones to each user for communication. doing. This system is mainly designed to provide voice communication services, and realizes voice communication services that transmit voice information at a constant transmission rate.

【0003】

In recent years, research has been conducted on the application of a multi-carrier CDMA (Code Division Multiple Access) wireless transmission method to a digital mobile communication system. In this research, it is mainly examined to accommodate more users (mobile stations) on the premise of information transmission at the same transmission rate.

【0004】

[Problems to be Solved by the Invention]

By the way, considering the transmission of multimedia information including image information (still image, moving image) and audio information, the type of information to be transmitted, the state of the transmission line between the base station and the mobile station, and the receiving side. It is preferable to make the information transmission rate variable depending on the information processing capability of the device.

【0005】

The multicarrier CDMA wireless transmission method uses a spread spectrum method in which a spread code is multiplied on the frequency axis for an information symbol for each user. For the multi-carrier CDMA wireless transmission method that transmits information to each user by such a method, information transmission at different transmission speeds has also been analyzed, but the specific method has been clarified. Absent.

【0006】

Therefore, an object of the present invention is to provide a multi-carrier CDMA wireless transmission method and device that enable wireless transmission of information at various transmission rates (transmission speeds) for each user.

【0007】

[Means for solving problems]

In order to solve the above problems, the present invention duplicates information symbols and arranges them on the frequency axis as described in claim 1, and multiplies the duplicated information symbols by a diffusion code on the frequency axis. In a multi-carrier CDMA wireless transmission method in which information symbols are accumulated and spread to multiple subcarrier components having different frequencies to perform multiplex transmission of information, each user who should transmit information is sent to the plurality of subcarrier components. It is configured to make the transmission rate of information variable by controlling the number of information symbols used for spreading the information and controlling the amount of information transmitted at the same time.

【0008】

In such a multi-carrier CDMA wireless transmission method, the amount of information simultaneously transmitted to the user is controlled by controlling the number of information symbols used for spreading. For users who should transmit information at a high transmission rate, the number of information symbols used for spreading should be increased, and for users who should transmit information at a low transmission rate, The number of information symbols used for diffusion is controlled to be smaller.

【0009】

When the number of information symbols used for spreading to a plurality of subcarrier components is controlled as described above, each information symbol is duplicated and arranged on the frequency axis with respect to the duplicated information symbol. By multiplying the spreading code on the frequency axis, each information symbol is spread to the components of a plurality of different subcarriers. Then, the components of the different subcarriers are multiplexed and transmitted as information to the corresponding user.

【0010】

The number of information symbols used for diffusion to the subcarrier component, that is, the transmission rate of information, is, for example, the environment of the wireless transmission line for the user (expressed by transmission / reception level, interference, error rate, etc.) and transmission. It is determined according to the type of information to be stored (still image, moving image, sound, etc.).

【0011】

From the viewpoint that the influence of interference on other users can be reduced when the receiving side (user side) decodes the information symbol for each user from the information in which the information symbol for each user is multiplexed using the spread code. As described in claim 2, the present invention is configured to use a code having an orthogonal relationship with each other as a spreading code used for spreading an information symbol for each user in the above-mentioned multi-carrier CDMA wireless transmission method. be able to.

【0012】

As described above, when the number of information symbols provided for spreading is controlled for each user, the present invention is claimed from the viewpoint of providing the relationship between the information symbols and the subcarriers assigned to the spreading. As described in Item 3, in each of the above-mentioned multi-carrier CDMA radio transmission methods, the number of subcarriers assigned to the spread of all information symbols transmitted simultaneously is fixed, and the number of subcarriers assigned to the spread of one information symbol is fixed. Can be configured to control.

【0013】

Further, as described in claim 4, in the multicarrier CDMA wireless transmission method, the number of information symbols used for spreading to the plurality of subcarrier components and the number of subcarriers assigned to spread one information symbol The numbers can be configured to be inversely proportional.

【0014】

From the same viewpoint as above, as described in claim 5, in each of the above-mentioned multicarrier CDMA radio transmission methods, the number of subcarriers assigned to the diffusion of information symbols is fixed, and the above-mentioned plurality of subs are used. It can be configured to control the number of subcarriers allocated to the entire spread of the number of information symbols depending on the number of information symbols used for spreading to the carrier components.

【0015】

Further, from the same viewpoint that it is possible to spread and multiplex the number of information symbols according to the transmission rate even if the same subcarrier group is used for each user, the present invention is described in claim 6. In each of the above-mentioned multi-carrier CDMA wireless transmission methods, the subcarrier group assigned to the spread of all the information symbols transmitted simultaneously is the same for each information symbol, and the spread code used for the spread of each information symbol is different. can do.

【0016】

In order to solve the above problems of the present invention, the present invention duplicates information symbols and arranges them on the frequency axis as described in claim 7, and spreads the duplicated information symbols on the frequency axis. In a multi-carrier CDMA wireless transmission method in which a code is multiplied and the information symbol is spread over a plurality of subcarrier components having different frequencies to perform multiplex transmission of information, each user who should transmit information is on the time axis. It is configured to make the information transmission rate variable by controlling the multiple transmission stop interval of information.

【0017】

In such a multi-carrier CDMA wireless transmission method, multiplex transmission of information is performed intermittently, and at that time, the transmission rate is variable by controlling the stop interval of the multiplex transmission of the information. For users who should transmit information at a high transmission rate, the multiplex transmission stop interval of information is controlled to be small, and for users who should transmit information at a low transmission rate, multiplex transmission of information. It is controlled so that the stop interval becomes large.

【0018】

Further, in order to solve the above-mentioned problem of the present invention, the present invention duplicates the information symbols and arranges them on the frequency axis as described in claim 8, and the duplicated information symbols are on the frequency axis. In a multi-carrier CDMA wireless transmission method in which a spread code is multiplied in 1 and the information symbol is spread over a plurality of subcarrier components having different frequencies to perform multiple transmission of information, the information symbol to be spread is obtained by data modulation. At that time, the transmission rate of information can be made variable by controlling the number of modulation multi-values.

【0019】

In such a multi-carrier CDMA wireless transmission method, for a user who should transmit information at a high transmission rate, the number of modulation multi-values becomes large when the information symbol to be diffused is obtained by data modulation. Is controlled by. Specifically, for example, a data modulation method such as a 16QAM method or a 32QAM method is used. On the other hand, for a user who should transmit information at a low transfer rate, when the information symbol to be diffused is obtained by data modulation, the number of modulation multi-values is controlled to be small. Specifically, for example, a data modulation method such as the QPSK method or the BPSK method is used.

【0020】

Further, the present invention claims 9 from the viewpoint that the information symbol for each user can be easily decoded from the information in which the information symbol for each user is multiplexed using different subcarriers on the receiving side (user side). In each of the above-mentioned multicarrier CDMA radio transmission methods, each subcarrier assigned to the diffusion of information symbols can be configured to be orthogonal on the frequency axis.

【0021】

From the viewpoint that the influence of interference between subcarriers can be eliminated, the present invention, as described in claim 10, each sub assigned to the diffusion of information symbols in each of the above multicarrier CDMA radio transmission methods. The frequency characteristics of the carriers can be configured so that the frequency spectra of adjacent subcarriers do not overlap.

【0022】

A plurality of different subcarriers assigned to the spread of the information symbol may be arranged discretely on the frequency axis as described in claim 11, and also according to claim 12. As described above, they may be arranged continuously on the frequency axis.

【0023】

Further, in order to solve the above-mentioned problem of the present invention, the present invention duplicates the information symbols and arranges them on the frequency axis as described in claim 13, and the duplicated information symbols are on the frequency axis. In a multi-carrier CDMA wireless transmission device that multiplies the information symbol in the above and spreads the information symbol to the components of a plurality of subcarriers having different frequencies to perform multiplex transmission of the information. It is configured to have a transmission rate control means for controlling the number of information symbols used for spreading the information to the subcarrier component and controlling the amount of information simultaneously transmitted.

【0024】

Further, as described in claim 20, the information symbols are duplicated and arranged on the frequency axis, the duplicated information symbol is multiplied by the spread code on the frequency axis, and the information symbol is multiplied by the frequency axis. Intermittent transmission control that controls the multiple transmission stop interval of information on the time axis for each user who should transmit information in a multi-carrier CDMA wireless transmission device that diffuses information to multiple components of different subcarriers and performs multiple transmission of information. It is configured to have means.

【0025】

Further, as described in claim 21, the information symbols are duplicated and arranged on the frequency axis, the duplicated information symbol is multiplied by the spread code on the frequency axis, and the information symbol is multiplied by the frequency axis. In a multi-carrier CDMA wireless transmission device that diffuses information into multiple components of different subcarriers and performs multiplex transmission of information, when the information symbol to be diffused is obtained by data modulation, the modulation multi-value that controls the modulation multi-value number is obtained. It is configured to have numerical control means.

【0026】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0027】

The multi-carrier wireless transmission device according to the embodiment of the present invention is configured as shown in FIG. 1, for example. This multi-carrier wireless transmission device is applied to, for example, a base station of a digital mobile communication system.

【0028】

In FIG. 1, this multi-carrier wireless transmission device has signal generation circuits 100 (1) to 100 (n) corresponding to each user (mobile station). Each signal generation circuit 100 (1) to 100 (n) generates a signal for each user, and is a transmission data that generates information (voice, data, etc.) to be distributed to each user as transmission data in a predetermined format. The information symbol serially output from the generator 11, the transmission data generator 11, the transmission path encoder 12 that encodes the transmission data from the transmission data generator 11 according to a predetermined algorithm, and the transmission path encoder 12 are converted into a parallel information symbol. It has a series-parallel conversion circuit 13 and a plurality of diffusion modulation units 14 (1) to 14 (m) that spread-modulate each information symbol output in parallel by the series-parallel conversion circuit 13 on the frequency axis. ..

【0029】

The series-parallel conversion circuit 13 converts the series information symbol string input from the transmission path encoder 12 in parallel to m information symbol strings based on the transmission rate designation control signal from the control unit (not shown). .. By controlling the number of information symbol strings obtained by this conversion, the amount of information transmitted at the same time is controlled, and as a result, the transmission rate of information is controlled.

【0030】

One of the information symbol strings output in parallel from the series-parallel conversion circuit 13 is input to each of the diffusion modulation units 14 (1) to 14 (m), and the information symbol string uses a diffusion code. Is diffusely modulated on the frequency axis. Although m diffusion modulation units 14 (1) to 14 (m) are shown in FIG. 1, they are actually output in parallel from the series-parallel conversion circuit 13 of the plurality of diffusion modulation units. The same number of diffusion modulators as the number of information symbol strings are used.

【0031】

Each diffusion modulation unit 14 (1) to 14 (m) is configured as shown in FIG. 2, for example. In FIG. 2, each diffusion modulation unit 14 (1) to 14 (m) has a duplication circuit 141 and a multiplier 142. The duplication circuit 141 duplicates the input information symbols by the number corresponding to the diffusion rate. The multiplier 142 multiplies the duplicated information symbol by the diffusion code Ci assigned to each user (i). As a result, the multiplier 142 outputs a diffusion signal composed of components corresponding to the subcarriers f1, f2, ..., Fk on the frequency axis.

【0032】

With the above configuration, each signal generation circuit 100 (1) to 100 (n) outputs a spread signal on the frequency axis obtained by multiplying the duplicated information symbol by the spread code, and signals to each user. Output as. The diffusion signal corresponding to each user output from each of these signal generation circuits 100 (1) to 100 (n) is synthesized by the synthesis unit 21 for each subcarrier component. The composite signal for each subcarrier component from the synthesizer 21 is frequency-time by IDFT (Inverse Discrete Fourier Transform) 22 (or IFFT (Inverse Fast Fourier Transform)). The transform is done. The synthesizer 21 and the IDFT 22 generate a multi-carrier CDMA signal in which information for each user is mixed.

【0033】

The multicarrier CDMA signal in which the information for each user is multiplexed as described above is sequentially processed by the guard interval insertion unit 23, the low frequency equalization filter 24, and the amplifier 25, and the processed signal is the antenna unit 56. Is sent from.

【0034】

In the multi-carrier CDMA transmission device as described above, the transmission rate of information is controlled by controlling the number of information symbols converted by the series-parallel conversion circuit 13 as described above. A more specific method of this transmission rate control will be described.

【0035】

In the first example, as shown in FIG. 3, each diffusion modulation unit 14 (1) to 14 (m) is configured so that the diffusion rate is variable.

【0036】

In FIG. 3, when m information symbols are output in parallel from the series-parallel conversion circuit 13, each diffusion modulation unit 14 (1) to 14 (m) to which one of them is input is input information. The symbol is diffused at a diffusion rate of n / m (n and m are natural numbers). That is, k (= n / m) input information symbols are duplicated, and one information symbol is diffused into components corresponding to k (= n / m) subcarriers on the frequency axis.

【0037】

In this way, when the diffusion rate n / m in each diffusion modulation unit 14 (1) to 14 (m) changes according to the number m of information symbols output in parallel from the series-parallel conversion circuit 13, the transmission rate and The relationship with the number of subcarriers assigned to the spread of each information symbol is shown in Fig. 4. When m = 1, that is, when 1 information symbol is transmitted, the diffusion rate is n as shown in Fig. 4 (a), and 1 information symbol becomes a component corresponding to n subcarriers on the frequency axis. It is diffused. In this case, the normalized transmission rate is 1. When m information symbols are transmitted at the same time, as shown in Fig. 4 (b), the diffusion rate is n / m, and one information symbol is a component corresponding to n / m subcarriers on the frequency axis. Is diffused to. Therefore, the total number of subcarriers assigned to the spread of m information symbols is always a constant value n. In this case, the normalized transmission rate m is m times the above normalized transmission rate.

【0038】

In the above example, when the transmission rate (transmission rate) is increased, the number of subcarriers used to transmit one information symbol is decreased, and conversely, when the transmission rate (transmission rate) is decreased. 1 The number of subcarriers used to transmit information symbols will be increased. The relationship between the transmission rate and the number of subcarriers used to transmit one information symbol is inversely proportional. Further, as shown in FIG. 5 (a), the subcarriers to be assigned to spread each information symbol are continuous on the frequency axis, as shown in FIG. 5 (b). It may be discrete on the frequency axis.

【0039】

By the way, in the above example, when the transmission rate is changed, the diffusion rate in each diffusion modulation unit 14 (1) to 14 (m) changes, so the period of the diffusion code Ci used must be changed accordingly. Must be. Further, when the transmission rate is changed for each information requested by the user, the period of the diffusion code Ci must be changed for each user as well. Therefore, when the transmission rate is controlled by the method as described above, the diffusion code having various cycles is used in the multicarrier CDMA wireless transmission device. Considering the decoding process of the information symbol for each user on the receiving side, it is preferable that the diffusion codes used are orthogonal to each other.

【0040】

Therefore, each spreading code used in such a multi-carrier CDMA wireless transmission device is determined so as to satisfy the following conditions.

【0041】

The diffusion code Ci with a period n × m is used to spread the information symbol for user i to n × m subcarrier components, and the period n to spread the information symbol for user k to n subcarrier components. When the diffusion code Ck of is used, each diffusion code Ci, Ck is [0042]

[Number 1]

<img file="JP2001237803A_D0001.tif" />By satisfying the above conditions, the relationship is orthogonal to each other.

【0043】

For example, the method for generating such diffusion codes Ci and Ck is "Orthogonal forward link using orthogonal multi-spreading factor codes for DS-CDMA mobileradio (K. Okawa and F. Adachi: IEICE Trans. Commun., Vol. E81). -B, No.4, pp777-784, April 1998) . In such a technique, for example, as shown in FIG. 6, each period (2) generated so as to be arranged hierarchically according to the Hadamard sequence.^m) (M = 1, 2, ...), The diffusion codes having a predetermined positional relationship are selected as the diffusion codes Ci and Ck having an orthogonal relationship.

【0044】

Next, in the second example of the specific method of transmission rate control, as shown in FIG. 7, each diffusion modulation unit 14'(1) to 14'(m) diffuses at a fixed diffusion rate. It is configured to perform processing.

【0045】

In FIG. 7, when m information symbols are output in parallel from the series-parallel conversion circuit 13, each diffusion modulator 14'(1) to 14'(m) to which one of them is input is input. The information symbol is always diffused at a diffusion rate n. That is, n input information symbols are duplicated, and one information symbol is always diffused to the components corresponding to n subcarriers on the frequency axis.

【0046】

In this way, when the diffusion rate n at each diffusion modulation section 14'(1) to 14'(m) is fixed regardless of the number m of information symbols output in parallel from the series-parallel conversion circuit 13. The relationship between the transmission rate and the number of subcarriers assigned to the spread of each information symbol is shown in FIG. When m = 1, that is, when one symbol is transmitted, the diffusion rate is n as shown in FIG. 8 (a), and one information symbol is diffused to the components corresponding to n subcarriers on the frequency axis. Will be done. In this case, the normalized transmission rate is 1. When m information symbols are transmitted at the same time, as shown in FIG. 8 (b), the diffusion rate is n as in the above case, and one information symbol is divided into n subcarriers on the frequency axis. It is diffused to the corresponding component. Therefore, the total number of subcarriers assigned to the spread of m information symbols is n × m. In this case, the normalized transmission rate m is m times the above normalized transmission rate.

【0047】

In the above example, when increasing the transmission rate (transmission rate), the total number of subcarriers used to transmit all information symbols while keeping the number of subcarriers used to transmit one information symbol constant. On the contrary, when the transmission rate (transmission rate) is decreased, the number of subcarriers used to transmit one information symbol is kept constant, and the number of subcarriers used to transmit all information symbols is constant. Reduce the total number. The relationship between the transmission rate and the total number of subcarriers used to transmit all information symbols is proportional.

【0048】

Note that the subcarriers to be assigned to spread each information symbol may be continuous or discrete on the frequency axis, as in the above example (see FIG. 5). Good. Further, it is preferable that the diffusion codes assigned to each user are also orthogonal to each other.

【0049】

Next, in the third example of the specific method of transmission rate control, as shown in FIG. 9, each diffusion modulation unit 14'' (1) to 14'' (m) uses the diffusion code Ci1 to. Cim is configured differently.

【0050】

In FIG. 9, when m information symbols are output in parallel from the series-parallel conversion circuit 13, each diffusion modulator 14'' (1) to 14'' (m) to which one of them is input is The information symbol to be input is always diffused at the diffusion rate n. That is, n input information symbols are duplicated, and one information symbol is always diffused to the components corresponding to n subcarriers on the frequency axis. The diffusion processing in each of the diffusion modulation units 14'' (1) to 14'' (m) is performed using different diffusion codes Ci1 to Cim.

【0051】

In this way, the m information symbols output in parallel from the series-parallel conversion circuit 13 use different diffusion codes Ci1 to Cim in each diffusion modulation section 14'' (1) to 14'' (m). When spread to the components corresponding to n subcarriers on the frequency axis, the relationship between the transmission rate, the number of subcarriers assigned to the spread of each information symbol, and the spread code is as shown in FIG. When m = 1, that is, when one symbol is transmitted, the diffusion rate is n as shown in FIG. 10 (a), and one symbol is a component corresponding to one set of n subcarriers on the frequency axis. Is diffused to. In this case, the normalized transmission rate is 1. Further, when m information symbols are transmitted at the same time, as shown in FIG. 10 (b), the diffusion rate in the frequency axis direction is n as in the above case, but the diffusion code in the frequency axis direction indicates m. It will take m kinds of diffusion forms. In this case, the normalized transmission rate m is m times the above normalized rate.

【0052】

As described above, the diffusion signal having the components corresponding to the n subcarriers f1 to fn output from each diffusion modulation unit 14'' (1) to 14'' (m) is sent to the synthesis circuit 15 (Σ). Is synthesized (for example, added) for each subcarrier component. Then, a synthetic diffusion signal having synthetic components corresponding to n subcarriers is output from the synthetic circuit 15 (Σ) as an output signal of the signal generation circuit 100 (i) (see FIG. 1) corresponding to the user i. To.

【0053】

In the above example, when the transmission rate (transmission rate) is increased, the number of spreading codes used for spreading the information symbol is increased, and conversely, when the transmission rate (transmission rate) is decreased, the information symbol is used. The number of spreading symbols used for spreading is reduced.

【0054】

The n subcarriers to be assigned to spread each information symbol may be continuous or discrete on the frequency axis, as in each of the above examples (Fig.). 5). Further, the diffusion codes Ci1 to Cim assigned to each user are preferably orthogonal to each other, and further, these diffusion codes are preferably orthogonal to each other.

【0055】

Next, a fourth example of a specific method of transmission rate control will be described.

【0056】

In this example, as shown in FIG. 11, the intermittent transmission control unit 16 is provided in front of the series-parallel conversion circuit 13 in each of the signal generation circuits 100 (1) to 100 (n) shown in FIG. The intermittent transmission control unit 16 transfers the transmission data to the series-parallel conversion circuit 13 that has been processed by the transmission line encoder 12 (see FIG. 1) based on the transmission rate control signal from the control unit (not shown). The transfer timing of is controlled. If you want to increase the transmission rate, as shown in Fig. 12 (a), the data transmission stop interval is shortened, and if you want to decrease the transmission rate, see Fig. 12 (b) and Fig. 12 (c). As shown, the data transmission stop interval is lengthened. In this way, the information transmission rate can be controlled by controlling the data transmission stop interval.

【0057】

When the transmission data whose transmission stop interval is controlled by the intermittent transmission control unit 16 as described above is input to the series-parallel conversion circuit 13, the transmission data is converted in parallel to an information symbol of a predetermined number of meters, and each information symbol thereof. Is diffused into n subcarrier components by the diffusion modulation section 14 (1) to 14 (m).

【0058】

Next, a fifth example of a specific method of transmission rate will be described.

【0059】

In this example, as shown in FIG. 13, the number of modulation multi-values of the data modulation in the transmission data generation unit 11 in each signal generation circuit 100 (1) to 100 (n) shown in FIG. 1 becomes the transmission rate control signal. Based on this, it is controlled by the modulation multi-value number designation unit 15. When it is desired to increase the transmission rate, the number of modulation multi-values is increased, and for example, the transmission data is modulated by the 16QAM method or the 64QAM method. Further, when it is desired to lower the transmission rate, the number of modulation multi-values is reduced, and the transmission data is modulated by, for example, the QPSK method or the BPSK method.

【0060】

This modulation method can be switched according to the environment of the wireless transmission line, for example, as shown in FIG. That is, a modulation method having a large modulation multi-value number is used for a user who is close to the base station BS and has a good reception condition, and a modulation multi-value number is used for a user who is away from the base station BS and has a poor reception condition. A small modulation method is used. Further, the modulation method can be switched according to the amount of information to be transmitted. For example, for users who receive a relatively large amount of information such as images and information from the Internet, a modulation method with a large number of modulation values is used, and information with a relatively small amount of information such as voice is used. For the user who receives the distribution, a modulation method having a small number of modulation multi-values is used.

【0061】

As described above, the method of controlling the transmission rate by switching the modulation method (multi-value modulation) according to the environment of the wireless transmission line and the amount of information to be transmitted is described in the first to fourth examples described above. Can also be applied. That is, information is transmitted at a relatively high transmission rate to users with good reception status and users who receive information distribution with a large amount of information, and users with poor reception status and information distribution with a small amount of information are received. Information is transmitted to the user at a relatively low transmission rate.

【0062】

In each of the above examples, each subcarrier used for the diffusion process is, for example, IFFT (Inverse Fast Fourier Transformer) or IDFT (Inverse Discrete Fourier Transformer) so as to be orthogonal on the frequency axis as shown in FIG. ) 22 is adjusted.

【0063】

Further, in each of the above-mentioned examples, in order to limit the band of the data component corresponding to each subcarrier, each subcarrier is placed on the frequency axis after waveform shaping is performed, for example, as shown in FIG. Used for data diffusion. As a result, the frequency characteristics of the subcarriers do not overlap, and the influence of interference between the subcarriers can be eliminated.

【0064】

It should be noted that the transmission rate of information to each user can be determined by any combination of two or more of the methods of the first example, the second example, the third example, the fourth example, and the fifth example described above. It is also possible to control.

【0065】

[Effect of the invention]

As described above, according to the invention of the present application according to claims 1 to 25, in the multicarrier CDMA wireless transmission system or device, the amount of information transmitted within a predetermined time is controlled for each user. It is possible to wirelessly transmit information at various transmission rates (transmission speeds) for each user.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the multi-carrier CDMA wireless transmission apparatus which concerns on one Embodiment of this invention.

[Figure 2]

It is a block diagram which shows the specific configuration example of each spread modulation part in the multi-carrier CDMA wireless transmission apparatus shown in FIG.

[Fig. 3]

It is a block diagram which shows the 1st example of the structure which concerns on transmission rate control.

[Fig. 4]

It is a figure which shows the relationship between the transmission rate in 1st example, and the number of subcarriers assigned to the spread of each information symbol.

[Fig. 5]

It is a figure which shows the example of the arrangement on the frequency axis of the subcarrier used for diffusion.

[Fig. 6]

It is a figure which shows an example of the generation method of the diffusion code which becomes an orthogonal relationship.

[Fig. 7]

It is a block diagram which shows the 2nd example of the structure which concerns on transmission rate control.

[Fig. 8]

It is a figure which shows the relationship between the transmission rate in the 2nd example, and the number of subcarriers assigned to the spread of each information symbol.

[Fig. 9]

It is a block diagram which shows the 3rd example of the structure which concerns on transmission rate control.

[Fig. 10]

It is a figure which shows the relationship between the transmission rate in the 3rd example, the subcarrier assigned to each information symbol, and the number of spreading codes used for spreading the subcarrier.

[Fig. 11]

It is a block diagram which shows the 4th example of the structure which concerns on transmission rate control.

[Fig. 12]

It is a figure which shows the control example of the transmission rate in the 4th example.

[Fig. 13]

It is a block diagram which shows the 5th example of the structure which concerns on transmission rate control.

[Fig. 14]

It is a figure which shows the mode example of the transmission rate control.

[Fig. 15]

It is a figure which shows an example of the relationship on the frequency axis of each subcarrier.

[Fig. 16]

It is a figure which shows another example of the relationship on the frequency of each subcarrier.

[Explanation of symbols]

11 Transmission data generator 12 Line coder 13 Series-to-parallel conversion circuit 14 (1) ~ 14 (m) Diffusion modulator 21 Synthesis section 22 IDFT (IFFT) 23 Guard interval insertion part 24 Low frequency equalization filter 25 amplifier 26 Antenna unit 100 (1) ~ 100 (n) signal generation circuit 141 Replica circuit 142 Multiplier