JP2000349689A - CDMA wireless communication system and method - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: To be relatively resistant to fading, shadowing, etc., to improve the quality, and to shorten the guard time and enlarge the cell radius in a TDD system. SOLUTION: In CDMA transmission, interleaved chips are interleaved to keep the quality of each symbol in a frame constant, and transmission power control speed is reduced to reduce overhead and reduce the amount of interference to other cells. Reduce. In addition, the transmission power is reduced by terminating the transmission when the quality is satisfied, so that the capacity can be increased. Further, by performing the reverse transmission power control, this effect can be further remarkable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CDMA (Code D)
The present invention relates to a CDMA wireless communication system and method for digital wireless communication using an ivision multiple access (ivision multiple access) system.

[0002]

2. Description of the Related Art FIG. 23 is a block diagram showing a configuration of a conventional CDMA radio communication apparatus. In this CDMA wireless communication apparatus, transmission data 1 is spread by spreading section 2 on the transmission side. The signal subjected to the spread processing is modulated by the modulator 3 and then amplified by the transmission amplifier 4. This signal is transmitted from the transmitting antenna 5. The amplification factor in the transmission amplifier 4 at this time is determined by the high-speed transmission power setting unit 6.

On the receiving side, a signal received by a receiving antenna 11 is detected by a detector 12 and despread by a despreader 13. Thereby, the reception data 14 is obtained.
In the received data 14, the slot quality detection unit 16 estimates the quality of a slot (divided by several symbols), and the high-speed transmission power control unit 15 calculates a high-speed transmission power control value based on the estimation result. You. This control information is sent to the high-speed transmission power setting section 6 on the transmission side.

The signals spread by the spreading section 2 are arranged in symbol order as shown in FIG. FIG. 24 shows an example in which there are a total of 8 symbols by 16-fold spreading,
One symbol is spread 16 times.

FIG. 25 is an explanatory diagram showing reception quality in a conventional CDMA radio communication apparatus. FIG. 25 shows an example in which two users, user A and user B, are transmitting with a shift of 5 chips. The fading in each line is independent.

For the signal of the user A, the transmission power is controlled by the high-speed transmission power setting unit 6 in accordance with a command from the high-speed transmission power control unit 15, thereby canceling fluctuations in line quality due to fading or the like. Therefore, FIG.
As shown in (1), the quality of the received data 14 becomes substantially constant. As described above, in the CDMA wireless communication apparatus, the transmission power control allows each user to transmit at the minimum required transmission power, thereby reducing the total interference of the system and improving the capacity.

FIG. 26 is an explanatory diagram showing the amount of interference in a conventional CDMA radio communication apparatus. As can be seen from FIG. 26, the MS transmission power has an inverse characteristic of fading between MS and BS_A. That is, the MS transmission power is MS
-Adjusted to cancel BS-A fading.

[0008] At this time, the fading between MS-BS_B is independent of the fading between MS-BS_A, so that the amount of interference with BS_B as another base station fluctuates to have a large peak as shown in the figure. Nevertheless, the average value of the interference is smaller than when the transmission power control is not performed. As a result, the total transmission power of the system can be reduced.

[0009]

However, in the above-mentioned conventional CDMA radio communication apparatus, the chips after the spreading processing are arranged in a concentrated manner in a continuous short time on the same frequency, so that fading, shadowing, etc. If the influence is effected for a short time in this series, all chips at that time deteriorate in quality at the same time. Therefore, there is a problem that the quality cannot be improved even if the spreading gain is obtained by performing the despreading process. This also means that
There is a problem that system capacity is limited because transmission is performed with large transmission power.

[0010] Also, CDMA-TDD (Time Division D)
In a system using the (uplex) scheme, the frequency is shared between uplink and downlink, so that, for example, the uplink reception at the base station needs to be completed before the downlink transmission starts. Therefore, a guard time for the propagation delay time is required,
In order to ensure transmission efficiency, the length is limited, which causes a problem that the cell radius is limited.

The present invention has been made in view of the above points, is relatively resistant to fading, shadowing, and the like, can improve quality, and can reduce the guard time and increase the cell radius in a TDD system. It is an object of the present invention to provide a CDMA wireless communication system and method capable of performing the above.

[0012]

SUMMARY OF THE INVENTION In a digital radio communication system, when a long burst error temporarily exists due to the effects of fading or the like, it is necessary to spread the burst error to reduce the influence on the error correction decoding unit. , Interleaving is performed. This interleaving is performed for each slot and cannot sufficiently cope with fading, shadowing, and the like.

The present inventor pays attention to the above point, and in the CDMA transmission, interleaving the spread chips makes it possible to keep the quality of each symbol in a frame constant and to reduce the speed of transmission power control. They have found that they can do this and have come to the present invention. As a result, it is possible to reduce the overhead and the amount of interference with other cells.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS CDM according to a first aspect of the present invention
A wireless communication system includes a spreading unit that spreads transmission data at a predetermined spreading factor, a chip interleaving unit that performs a chip interleaving process on the spread transmission data, and a transmission device that includes a transmission unit that transmits the transmission data. And a receiving device including a receiving means for receiving the transmission data subjected to the chip interleaving processing and a chip deinterleaving means for performing deinterleaving processing on the received data for each chip.

According to this configuration, since chips for one symbol are allocated to a plurality of slots, delays and errors in transmission power control can be allowed during high-speed fading or the like. For this reason, by performing chip deinterleaving and despreading the chip-interleaved spread signal, it is possible to reduce variation in quality between symbols.

[0016] The CDMA radio communication system according to the second aspect of the present invention employs, in the first aspect, a configuration for performing low-speed transmission power control that follows a relatively slow change in propagation path conditions.

According to this configuration, since chips for one symbol are assigned to a plurality of slots, chips for one symbol are assigned to slots with good signal quality and slots with bad signal quality. That is, even if low-speed transmission power control is performed, a certain level of quality can be maintained.

[0018] In the CDMA radio communication system according to the third aspect of the present invention, in the first or second aspect, the receiving device comprises quality detecting means for detecting the quality of received data, and The transmission power is attenuated based on the detection result.

In the third aspect, it is preferable to adopt a configuration in which the transmission power is attenuated when the quality of the received data exceeds a threshold, as in the CDMA radio communication system according to the fourth aspect of the present invention.

According to these arrangements, if the data quality is better than a certain threshold, no further signal is transmitted, so that the transmission power control is performed until the data quality exceeds a certain threshold. When the data quality exceeds the threshold, the transmission power is attenuated. This reduces interference with other stations after attenuation. Therefore, the total transmission power of the entire system can be significantly reduced.

A CDMA radio communication system according to a fifth aspect of the present invention provides the CDMA radio communication system according to any one of the first to fourth aspects, wherein the transmission power is increased when the propagation path condition is good,
A configuration is employed in which the transmission power is controlled so as to reduce the transmission power when the propagation path condition is poor.

According to this configuration, a high-quality signal is transmitted with higher power. In such a case, however, the line is advantageous for transmission. Dramatic improvement in quality can be achieved. In addition, for low-quality signals, the transmission power is reduced, so that interference does not reach other users.

[0023] In the CDMA radio communication system according to the sixth aspect of the present invention, in any one of the first to fifth aspects, the receiving apparatus performs likelihood estimation on chip deinterleaved data. A configuration having a degree estimating means is adopted.

According to this configuration, since the likelihood estimation is performed according to the data quality, it is possible to obtain an S / N ratio rather than simply combining the signals interleaved by the chips, and to obtain good data. As a result, the reception quality is improved and the transmission power can be reduced accordingly, so that the total transmission power can be further reduced.

[0025] In a CDMA radio communication system according to a seventh aspect of the present invention, in the first aspect, the receiving apparatus may further include: a synchronization detecting means for measuring an arrival time of received data; Transmission power control means for controlling the transmission time length so as to complete reception within a specified time and keep the total transmission power constant, and performing control to increase the transmission power.

According to this configuration, it is possible to complete reception within a prescribed time while satisfying the required frame quality required for decoding in a short time with a large transmission power. As a result, it is possible to complete the reception at the receiving device within the specified time for all the transmitting devices.

[0027] In a CDMA radio communication system according to an eighth aspect of the present invention, the transmission power control means according to the seventh aspect further comprises: Before the transmission signal of the transmitting device is received, the transmission time length is controlled so as to complete the reception.

According to this configuration, the amount of interference of the transmission signal of the transmission device with the transmission signal of another transmission device is reduced.
Therefore, the transmission power for satisfying the required frame quality can be reduced for the other transmission devices as compared with the seventh aspect, and the reception within the specified time is completed while reducing the total transmission power for all the transmission devices that satisfies the required quality. I can expect that.

[0029] In a CDMA radio communication system according to a ninth aspect of the present invention, the transmission power control means according to the seventh aspect or the eighth aspect, wherein the transmission power control means has a difference in arrival time of received data from a plurality of transmitting apparatuses. When there is no transmission, a configuration is employed in which control is performed to delay the transmission start time of the desired transmission device.

According to this configuration, by controlling the transmission start time of each transmission device to be shifted, the arrival time can be dynamically shifted even when there is no difference in the arrival time between the transmission devices. Can be reduced. This gives a degree of freedom and enables efficient transmission.

[0031] A CDMA radio communication system according to a tenth aspect of the present invention, in any one of the seventh to ninth aspects, comprises a detecting means for detecting the quality of received data,
The transmission power control means controls the transmission power of the transmission device according to the detected quality of the received data.

According to this configuration, the reception quality can be further improved by using the seventh to ninth aspects together with power control for fluctuations such as fading.

[0033] In the CDMA radio communication system according to the eleventh aspect of the present invention, in any one of the seventh aspect to the tenth aspect, the transmission power control means may require that the quality of the received data detected by the detection means be required. After the frame quality is satisfied, a configuration is employed in which control is performed to cause the transmitting device to terminate transmission.

According to this configuration, the seventh to tenth aspects are described.
By stopping the transmission when the required frame quality is satisfied in the aspect described above, interference with other users can be reduced, and the total transmission power can be suppressed to save the battery of the mobile station.

[0035] In the CDMA radio communication system according to the twelfth aspect of the present invention, in any one of the seventh to eleventh aspects, the receiving apparatus performs likelihood estimation on the chip deinterleaved data. The present invention employs a configuration including a likelihood estimating means for performing, and a combining means for performing weighting on the data based on the estimated likelihood and then combining the data.

According to this configuration, reception data is obtained by weighting and combining based on the likelihood estimated from the signal after chip deinterleaving, so that the S / N can be obtained rather than simply combining. And good received data can be obtained.

A communication terminal according to a thirteenth aspect of the present invention is used for any one of the first to twelfth CDMA wireless communication systems. According to this configuration, battery saving can be achieved.

A base station apparatus according to a fourteenth aspect of the present invention is used for any one of the first to twelfth CDMA radio communication systems. According to this configuration, interference from the communication terminal device is reduced, and good wireless communication can be performed.

In a CDMA radio communication method according to a fifteenth aspect of the present invention, after performing chip interleave processing on data spread at a predetermined spreading factor, the data is transmitted, and the received chip interleave processing is performed. A configuration is employed in which deinterleaving processing is performed on data for each chip and then despreading processing is performed.

According to this configuration, since chips for one symbol are allocated to a plurality of slots, control delays and errors can be tolerated during high-speed fading or the like. For this reason, by performing chip deinterleaving and despreading the chip-interleaved spread signal, it is possible to reduce variation in quality between symbols.

A CDMA radio communication method according to a sixteenth aspect of the present invention employs, in the fifteenth aspect, a configuration for performing low-speed transmission power control that follows a relatively slow change in propagation path conditions.

According to this configuration, since chips for one symbol are allocated to a plurality of slots, chips for one symbol are allocated to slots with good signal quality and slots with bad signal quality. That is, even if low-speed transmission power control is performed, a certain level of quality can be maintained.

A CDMA radio communication method according to a seventeenth aspect of the present invention employs a configuration according to the fifteenth or sixteenth aspect, wherein the quality of data is detected and the transmission power is attenuated based on the result of the detection.

According to this configuration, no further transmission is performed according to the detection result of the data quality, so that interference with other stations is reduced after attenuation. Therefore, the total transmission power of the entire system can be significantly reduced.

A CDMA radio communication method according to an eighteenth aspect of the present invention provides the CDMA radio communication method according to any one of the fifteenth to seventeenth aspects, wherein the transmission power is increased when the propagation path condition is good.
A configuration is employed in which the transmission power is controlled so as to reduce the transmission power when the propagation path condition is poor.

According to this configuration, a high-quality signal is transmitted with higher power. In such a case, however, the line is advantageous for transmission, so that a slight increase in power facilitates transmission. Dramatic improvement in quality can be achieved. In addition, for low-quality signals, the transmission power is reduced, so that interference does not reach other users.

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

(Embodiment 1) FIG.1 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 1 of the present invention.

In the transmitter, transmission data 101 is subjected to spreading processing in spreading section 102 and then to chip interleaving section 10.
At 7, the chip is interleaved. The interleaved signal is modulated by the modulation unit 103 and transmitted by the transmission amplifier unit 10.
After being amplified at 4, it is radiated from the transmitting antenna 105.

In the receiver, the signal received by the receiving antenna 111 is detected by the detection unit 112, and the chip deinterleave unit 117 performs rearrangement reverse to the chip interleave for transmission. The deinterleaved data is combined by the despreading unit 113 to obtain received data 114. Further, slot quality of received data 114 is detected by slot quality detecting section 116, and high-speed transmission power control section 115 generates a signal for high-speed transmission power control according to the detection result and transmits the signal to the transmitter. In the transmitter, high-speed transmission power setting section 106 sets high-speed transmission power based on the control signal, and controls the amplification factor in transmission amplifier section 104.

Next, the operation of the CDMA radio communication apparatus having the above configuration will be described.

Transmission data 101 is spread by spreading section 102 and is subjected to chip interleaving processing by chip interleaving section 107. FIG. 2 shows an example of chip interleaving. This example is an example of spreading 16 times with 7 symbols per slot.

In FIG. 2, symbol 0 is spread to 1
6 chips. At this time, the 16 chips are not placed at a continuous position, but are arranged every 8 chips. The other symbols 1 to 7 are spread 16
The chips are not placed in a continuous position, but are placed every eight chips. Therefore, in the spread signal subjected to the chip interleave processing, chip (0-1) of symbol 0
, Chip 1 of symbol 1 (0-2), chip 2 of symbol 2 (0-3), ... chip 7 of symbol 7 (0-16)
Are arranged in this order.

Thus, high-speed power control capable of following fading can be performed. This will be specifically described with reference to FIGS. 25 and 26. In FIG. 25, the spreading factor 1
If the number of symbols is N and the number of symbols is N, the user A slot 0
In Nos. To 15, the 0th to 15th chips are arranged for symbols 0 to N-1, respectively, for chip interleaving.

Due to the user A fading, the quality does not change so much within the slot, but changes greatly from slot to slot. In this system, since the high-speed transmission power control is performed, the quality of the user A signal is fairly constant between the slots, but the quality is not always constant at the time of high-speed fading due to control delays and errors. .

In the present embodiment, since the chip interleave processing is performed, chips for one symbol are allocated to a plurality of slots. Therefore, control delays and errors can be tolerated during high-speed fading and the like. Therefore, the chip-interleaved spread signal is chip-deinterleaved and despread, so that in the case of 16-fold spread, S / N
(Signal noise) ratio can be improved by about 12 dB, and variation in quality between symbols can be reduced. As shown in FIG. 25, even if the user B slot is shifted from the user A slot by 5 slots,
The effect remains the same.

Further, as shown in FIG. 26, the interference of the signal of user A on BS_B due to BS_A performing transmission power control on user A is the same as the conventional value as the relative value to the transmission power. However, as described above, since the error correction capability is improved by the amount by which the variation in quality between symbols is suppressed and the total transmission power is suppressed, the absolute amount can be reduced.

As described above, the CDMA according to the first embodiment
According to the wireless communication system including the wireless communication device, it is possible to reduce the total transmission power and thereby increase the capacity.
Although this method is effective for downstream signals, it is more effective for upstream signals. Further, since the total transmission power can be reduced in this way, battery saving of a communication terminal device such as a mobile station can be achieved at the same time.

(Embodiment 2) FIG. 3 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 2 of the present invention.

In the transmitter, transmission data 301 is subjected to spreading processing in spreading section 302 and then to chip interleaving section 30.
At 7, the chip is interleaved. The interleaved signal is modulated by the modulation section 303 and transmitted by the transmission amplifier section 30.
After being amplified at 4, it is radiated from the transmitting antenna 305.

In the receiver, the signal received by the receiving antenna 311 is detected by the detection unit 312, and the chip deinterleave unit 317 rearranges the signal in the reverse order of the chip interleave for transmission. The deinterleaved data is combined by the despreading unit 313 to obtain received data 314. Further, slot quality of received data 314 is detected by slot quality detecting section 316, and low-speed transmission power control section 315 generates a low-speed transmission power control signal according to the detection result and transmits the signal to the transmitter. In the transmitter, low-speed transmission power setting section 306 sets low-speed transmission power based on the control signal, and controls the amplification factor in transmission amplifier section 304. Here, the low-speed transmission power control means a control that does not follow an intense level fluctuation such as Rayleigh fading, but only follows a gentle fluctuation such as attenuation due to distance fluctuation or attenuation due to shadowing. , In the specification.

The operation of the CDMA radio communication apparatus having such a configuration is the same as that of the first embodiment except that low-speed transmission power control is performed. In this case, low-speed power control that can follow only a slow variation such as a distance variation is performed without intentionally following the fading. This will be specifically described with reference to FIGS. In FIG.
Assuming that the number of symbols is N and the total number of symbols is N, user A slot 0
In Nos. To 15, the 0th to 15th chips are arranged for symbols 0 to N-1, respectively, for chip interleaving.

Although the quality does not change so much in the slot due to the user A fading, it greatly changes in each slot. In this system, since the low-speed transmission power control is performed, the user A signal quality varies considerably between slots. In the present embodiment, since chip interleaving processing is performed, chips for one symbol are allocated to a plurality of slots. Therefore, chips for one symbol are allocated to slots with good signal quality and slots with bad signal quality, and even if low-speed transmission power control is performed, the probability that the quality of all chips deteriorates is extremely low.

The chip-interleaved spread signal is chip-deinterleaved and despread to obtain a spread signal of 16 bits.
The same improvement effect as the equal gain combining diversity of the branch can be obtained, and the variation in quality between symbols can be reduced. As shown in FIG. 4, even if the user B slot is shifted from the user A slot by 5 slots, the effect remains unchanged.

Further, as shown in FIG. 5, regarding the interference of the signal of user A to BS_B, BS_A
By performing low-speed transmission power control on the transmission power, the amount of peak interference can be reduced (solid line in the figure) as compared with the interference according to the first embodiment (dotted line in the figure). This eliminates the need for transmission with excessive power, and can reduce the total transmission power in the system.

As described above, the CDMA according to the second embodiment
According to the wireless communication system including the wireless communication device, it is possible to further reduce the total transmission power and thereby increase the capacity. Further, since the peak value of the transmission power control can be reduced, the dynamic range of the transmission amplifier can be suppressed, and power consumption and cost can be reduced.

(Embodiment 3) FIG.6 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 3 of the present invention.

In the transmitter, transmission data 601 is subjected to spreading processing by spreading section 602 and then transmitted to chip interleaving section 60.
At 7, the chip is interleaved. The interleaved signal is modulated by the modulation section 603, and the transmission amplifier section 60
After being amplified at 4, it is radiated from the transmitting antenna 605.

In the receiver, the signal received by the receiving antenna 611 is detected by the detection unit 612, and the chip deinterleave unit 617 performs rearrangement reverse to the chip interleave for transmission. The deinterleaved data is combined by the despreading unit 613 to obtain received data 614. Further, the frame quality of the received data 614 is detected by a frame quality detection unit 616, and a transmission power attenuation control unit 615 generates a transmission power attenuation control signal in accordance with the detection result and transmits the signal to a transmitter. In the transmitter, the transmission power is set by the transmission power attenuation setting unit 606 based on the control signal, and the amplification factor of the transmission amplifier 604 is controlled.

The operation of the CDMA radio communication apparatus having such a configuration is the same as that of the first embodiment except that transmission power attenuation control is performed. That is, the transmission time is shortened by transmission power attenuation control when transmission is performed with excessive quality. Therefore, signals can be transmitted with the minimum necessary total transmission power.

A specific description will be given with reference to FIGS. 7 and 8. In FIG. 7, assuming that the spreading factor is 16 and the total number of symbols is N, the user A slots 0 to 15 have the 0th symbol for each of the symbols 0 to N−1 for chip interleaving.
The fifteenth through fifteenth chips are respectively arranged.
Here, slots 0 to 15 are defined as one frame.

Although the quality does not change so much in the slot due to the fading of the user A, the quality greatly changes in each slot. In this system, since the transmission power attenuation control is performed, that is, if the frame quality is better than a certain threshold, the signal after that time is not transmitted. Until the transmission power exceeds the threshold, the high-speed transmission power control of the first embodiment or the low-speed transmission power control of the second embodiment is performed. When the user A frame quality exceeds a threshold, the transmission power is attenuated.

For example, as shown in FIG. 7, when the user B slot is shifted from the user A slot by 5 slots, if the user A frame quality exceeds the threshold and the transmission power is attenuated, the user B slot 0 No. 4 does not interfere with the signal of the user A. As a result, it can be expected that the frame quality of the user B exceeds the threshold value quickly. As a result, the transmission power of the signal of the user B is attenuated quickly, and as a result, the signal quality of the user A is also improved. As described above, the signal quality is synergistically improved due to the attenuation of the transmission powers of the users A and B, and the total transmission power of the entire system can be significantly reduced.

Further, as shown in FIG. 8, regarding the interference of the signal of user A to BS_B, BS_A
By performing transmission power attenuating control on (1), the amount of peak interference can be reduced (solid line in the figure) as compared with the interference according to the first embodiment (dotted line in the figure). Also,
Since the transmission power in the latter half of the frame can be set to 0, the total transmission power can be reduced.

As described above, the CDMA according to the third embodiment
According to the wireless communication system including the wireless communication device, it is possible to further reduce the total transmission power and increase the capacity as compared with the first and second embodiments.

(Embodiment 4) FIG.9 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 4 of the present invention.

In the transmitter, transmission data 901 is subjected to spreading processing in spreading section 902 and then to chip interleaving section 90.
At 7, the chip is interleaved. The interleaved signal is modulated by the modulation section 903, and the transmission amplifier section 90
After being amplified at 4, it is radiated from the transmitting antenna 905.

In the receiver, the signal received by the receiving antenna 911 is detected by the detecting section 912, and the chip deinterleaving section 917 performs rearrangement reverse to the chip interleaving for transmission. The deinterleaved data is combined by the despreading unit 913 to obtain received data 914. Further, the frame quality of the received data 914 is detected by a frame quality detection unit 916, and a signal for reverse transmission power control is generated by a reverse transmission power control unit 915 according to the detection result, and transmitted to the transmitter. In the transmitter, reverse transmission power setting section 906 performs reverse transmission power setting based on this control signal, and controls the amplification factor in transmission amplifier section 904.

The operation of the CDMA radio communication apparatus having such a configuration is the same as that of the first embodiment except that reverse transmission power control is performed. That is, in the normal transmission power control, the transmission power is increased when the quality is poor, and the transmission power is decreased when the quality is good. The power is increased and the transmission power of poor quality signals is reduced.

In the case of such a control, a high-quality signal is transmitted with higher power. In such a case, however, the line is advantageous for transmission, so that a slight increase in power facilitates transmission. Dramatic improvement in quality can be achieved. On the other hand, for a signal of poor quality, even if the transmission power is slightly increased, the quality cannot be expected to be improved so much. Therefore, the transmission power is reduced to prevent interference with other users.

This will be described specifically with reference to FIGS. 10 and 11. In FIG. 10, assuming that the spreading factor is 16 and the total number of symbols is N, the 0th to 15th chips for symbols 0 to N−1 are provided in user A slots 0 to 15 for chip interleaving, respectively. Each is arranged. Here, slots 0 to 15 are defined as one frame.

Although the quality does not change so much in the slot due to the user A fading, it greatly changes in each slot. In this system, reverse transmission power control is performed, and as shown in FIG. 10, when the transmission power is increased for a high quality signal (the peak of the user A signal quality), the quality becomes very high, and the quality becomes high. Even if the transmission power is reduced for a bad signal (valley of user A signal quality), the quality does not change much.

Although the quality does not change so much in the slot due to the fading of the user A, the quality greatly changes in each slot. In the present embodiment, since chip interleaving processing is performed, chips for one symbol are allocated to a plurality of slots. Therefore, chips for one symbol are assigned to slots with good signal quality and slots with bad signal quality, and even if reverse transmission power control is performed,
The probability that all chips will be degraded is very low.

The chip-interleaved spread signal is chip-deinterleaved and despread to obtain 16
An improvement effect close to the maximum ratio combining diversity of the branches can be obtained, and the variation in quality between symbols can be reduced.

Here, when the transmission power attenuation control of the third embodiment is also used, control is performed so that the higher the reception quality, the higher the transmission power, the higher the transmission power, until the user A frame quality exceeds a certain threshold. When the threshold value is exceeded, the transmission power is attenuated. Accordingly, since the signal of user A is transmitted with high power in a time zone of good quality, the threshold value can be exceeded earlier than in the third embodiment, and transmission attenuation can be performed earlier.

For example, as shown in FIG. 10, when the user B slot deviates from the user A slot by 5 slots and the user A frame quality exceeds the threshold and the transmission power is attenuated, the user B slot 0 No. 4 does not interfere with the signal of the user A. As a result, it can be expected that the frame quality of the user B exceeds the threshold value quickly. Also,
The reverse transmission power control causes transmission attenuation earlier than in the third embodiment, thereby further improving the signal quality of user A, so that the total transmission power of the entire system can be significantly reduced. Further, the total transmission power can be reduced without performing the transmission power attenuation control.

Further, as shown in FIG. 11, with respect to the interference of the signal of user A on BS_B, BS_A performs reverse transmission power control on user A, thereby obtaining interference (BS) in the first embodiment. The interference amount can be reduced as compared with the dotted line in the figure) (solid line in the figure). Also, by using the transmission power attenuation control of the third embodiment together, the transmission power in the latter half of the frame can be set to 0, so that the total transmission power can be further reduced.

As described above, the CDMA according to the fourth embodiment
According to the wireless communication system including the wireless communication device, the total transmission power can be further reduced and the capacity can be further increased as compared with the first to third embodiments.

(Embodiment 5) FIG.12 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 5 of the present invention.

In the transmitter, transmission data 1201 is subjected to spreading processing in spreading section 1202 and then to chip interleaving processing in chip interleaving section 1207. The interleaved signal is modulated by modulation section 1203 and amplified by transmission amplifier section 1204, and then transmitted by transmission antenna 1205.
Radiated from

In the receiver, the signal received by reception antenna 1211 is detected by detection section 1212, and is rearranged by chip deinterleave section 1217 in the reverse order of transmission chip interleave. The deinterleaved data is combined by the maximum ratio despreading unit 1213 to obtain received data 1214. The maximum ratio despreading unit 1213 is
The likelihood estimating unit 1218 performs weighting based on the likelihood estimated from the signal after chip deinterleaving, and then performs synthesis.

Further, frame quality of received data 1214 is detected by frame quality detecting section 1216, and reverse transmission power control section 1215 generates a signal for reverse transmission power control according to the detection result and transmits the signal to the transmitter. In the transmitter, reverse transmission power setting section 1206 performs reverse transmission power setting based on the control signal, and controls the amplification factor in transmission amplifier section 1204.

The operation of the CDMA radio communication apparatus having such a configuration is the same as that of the fourth embodiment except that likelihood estimation is performed. That is, C according to Embodiment 4
In addition to the function of the DMA wireless communication device, the maximum ratio despreading unit 1
Since the likelihood estimation is performed by the 213 and the likelihood estimating unit 1218, the S / N ratio can be increased as compared with the case where the signals interleaved by the chips are simply combined, and good received data 1214 can be obtained. In addition, this improves the reception quality and thereby reduces the transmission power, so that the total transmission power can be further reduced.

As described above, the CDMA according to the fifth embodiment
According to the wireless communication system including the wireless communication device, it is possible to further reduce the total transmission power and increase the capacity as compared with the first to fourth embodiments.

The CDMA radio communication apparatuses according to Embodiments 1 to 5 can be applied to communication terminals such as mobile station apparatuses and base station apparatuses in a radio communication system.

In the first to fifth embodiments, the case where temporal interleaving is performed as interleaving is described. However, similar effects can be obtained when interleaving between frequencies is performed as interleaving. The first to fifth embodiments can be implemented in appropriate combinations.

(Embodiment 6) FIG.13 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 6 of the present invention.

In the transmitter, transmission data 1301 is subjected to spreading processing in spreading section 1302 and then to chip interleaving processing in chip interleaving section 1307. The interleaved signal is modulated by modulation section 1303 and amplified by transmission amplifier section 1304, after which transmission antenna 1305
Radiated from

In the receiver, the signal received by receiving antenna 1311 is detected by detecting section 1312, and is rearranged by chip deinterleaving section 1317 in the reverse order of transmission chip interleaving. The deinterleaved data is synthesized by the despreading unit 1313 and the received data 1
314 are obtained.

Further, the reception time of the reception data 1314 is measured by the synchronization detection unit 1316 and the transmission power control unit 131
In step 5, for a user whose arrival time at the base station corresponding to the receiver is late, a control signal for the transmission time length and the transmission power is generated so that the reception is completed within the specified time and the total transmission power is constant. To the transmitter.

In the transmitter, transmission time and transmission power are set in transmission power setting section 1306 based on the control signal, and the amplification factor and transmission time in transmission amplifier section 1304 are controlled.

The operation of the CDMA radio communication apparatus having such a configuration is as follows. For a user whose arrival time is late, the total transmission power is kept constant so that the reception is completed within a specified time, and the transmission time length and the transmission power are adjusted. Controlled.

For a user whose arrival time is late, the transmission time length is determined so that the reception is completed within the specified time. Therefore, the transmission time is increased, but the transmission power is increased to compensate for this. Since the transmission signal is subjected to chip interleaving, if the required frame quality is satisfied, decoding is possible even if only a part of the burst can be received.

This will be specifically described with reference to FIG. FIG.
4, if the spreading factor is 16 times and the total number of symbols is N, the user slots 0 to 15 have the 0th to 0th symbols for each symbol 0 to N−1 for chip interleaving.
The fifteenth chips are respectively arranged. Here, slots 0 to 15 are defined as one frame.

In the figure, the first stage shows the operation timing of the base station, the second stage shows the uplink transmission timing of the user A, and the third stage shows the reception timing of the transmission signal from the user A at the base station.

Here, the reception of the signal from the user A is not completed within the specified time. Therefore, as shown in the fourth row, the transmission time length is limited so that reception is completed within a specified time. This transmission time length is determined from the measured arrival time and the operation timing of the base station. At this time, in order to compensate for the shortening of the reception time, the transmission is performed by increasing the transmission power so that the total transmission power becomes equal. If the transmission power is large, it is expected that the required frame quality required for decoding can be satisfied in a short time, so that the reception can be completed within a specified time.

As described above, CDMA according to Embodiment 6
According to a wireless communication system including a wireless communication device, a receiver measures the arrival time of received data, and for a transmitter having a slow arrival time, reception is completed within a specified time and the total transmission power is reduced. Since the transmission time length is controlled so as to be constant and the transmission power is controlled to be increased, the reception is completed within the specified time while satisfying the required frame quality required for decoding in a short time with a large transmission power. be able to. Thereby, the reception at the base station (receiver) can be completed for all the users (transmitters) within the specified time.

(Embodiment 7) FIG.15 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 7 of the present invention.

The operations of the transmitter and the receiver are the same as those in the sixth embodiment except that the transmission time length control is performed for the user whose arrival time is short. The all-user transmission power control unit 1501 in FIG. 15 controls the transmission time length of all users based on arrival time information measured from synchronization detection for each user.

The operation of the CDMA radio communication apparatus having such a configuration will be described with reference to FIG.

In FIG. 16, assuming that the spreading factor is 16 and the total number of symbols is N, the 0th to 15th symbols for each symbol 0 to N−1 are provided in each user slot 0 to 15 for chip interleaving. Chips are arranged. Here, slots 0 to 15 are defined as one frame.

In the figure, the first stage shows the operation timing of the base station, the second stage shows the uplink transmission timing of the user A, and the third stage shows the reception timing of the transmission signal from the user A at the base station.

However, the timing in the figure is on the receiving side. For simplicity, it is assumed that only the user A and the user B are accommodated in the base station (receiver). It is assumed that the reception of the user A is completed within the specified time at the base station, but the reception of the user B is not completed within the specified time.

At this time, the sixth embodiment is applied to the user B.
By performing transmission in the same manner as described above, it is possible to complete the reception of the user B within the specified time. Further, for the user A, the transmission time length is limited so that the reception is completed before the later user starts the reception, and the transmission power is increased so that the total transmission power is fixed to compensate for the shortened reception time. Send.

As described above, CDMA according to Embodiment 7
According to the wireless communication system including the wireless communication device, the amount of interference of the transmission signal of the transmitter of user A on the transmission signal of the transmitter of user B is reduced. Therefore, the transmission power for satisfying the required frame quality for user B can be reduced as compared with the sixth embodiment, and it is expected that the reception within a specified time is completed while reducing the total transmission power for satisfying the required quality for all users. it can.

(Embodiment 8) FIG.17 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 8 of the present invention.

In the transmitter, transmission data 1301 is subjected to spreading processing in spreading section 1302 and then to chip interleaving processing in chip interleaving section 1307. The interleaved signal is modulated by modulator 1303, amplified by transmission amplifier 1304, and radiated from transmission antenna 1305.

In the receiver, the signal received by receiving antenna 1311 is detected by detecting section 1312, and chip deinterleaving section 1317 performs rearrangement in the reverse order of chip interleaving for transmission. The deinterleaved data is synthesized by the despreading unit 1313 and the received data 1
314 are obtained.

Further, for the received data 1314, the arrival time of the signal is measured by the synchronization detecting unit 1316, and the transmission start time control unit 1701 for all users adds a delay to the transmission start time of the user having no difference in the arrival time. A control signal to be given is generated, and a signal for controlling transmission time length and transmission power is generated for each user as in the sixth and seventh embodiments. Based on this control signal, the transmission power setting unit 1306 sets the transmission time length and transmission power, and the transmission start time setting unit 1702 gives a delay to the transmission start time.

The operation of the CDMA radio communication apparatus having such a configuration is the same as that of the sixth embodiment except that the transmission start time is controlled.

That is, by performing the transmission start time control, the arrival time can be dynamically shifted even when there is no difference in the arrival times between the users, and interference between the users can be reduced. Therefore, more flexible control is possible.

This will be specifically described with reference to FIG. FIG.
In the equation, if the spreading factor is 16 and the total number of symbols is N,
In each user slot 0 to 15, the 0th to 1st symbols for each symbol 0 to N-1 are provided for chip interleaving.
Fifth chips are respectively arranged. Here, slots 0 to 15 are defined as one frame. Each timing in the figure is displayed according to the base station side (reception side).

It is assumed that user A and user B are accommodated in the base station, and that there is almost no difference between the reception timings of user A and user B at the base station. At this time,
By giving a delay to the transmission start time of the user B, interference from the user A to the transmission signal of the user B can be reduced.

As described above, the CDMA according to Embodiment 8
According to the wireless communication system including the wireless communication device, the control to shift the transmission start time of the transmitter of each user enables the arrival time to be dynamically shifted even when there is no difference in the arrival time between the users. Thus, interference between users can be reduced. This gives a degree of freedom and enables efficient transmission.

(Embodiment 9) FIG.19 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 9 of the present invention.

In the transmitter, transmission data 1301 is subjected to spreading processing in spreading section 1302 and then to chip interleaving processing in chip interleaving section 1307. The interleaved signal is modulated by modulation section 1303 and amplified by transmission amplifier section 1304, and then transmitted by transmission antenna 1306.
Radiated from In the receiver, the signal received by the reception antenna 1311 is detected by the detection unit 1312, and the chip deinterleave unit 1317 performs rearrangement reverse to the chip interleave for transmission. The deinterleaved data is combined by the despreading unit 1313 to obtain received data 1314.

Further, the reception data 1314 is supplied to a synchronization detection unit 1316 where the arrival time of the signal and the frame quality detection unit 190 are detected.
1, the transmission quality control unit 1902 generates a control signal for delaying the transmission start time of a user having no difference in arrival time, and the transmission time length and transmission power A control signal and a power control signal are generated. The operation of the CDMA wireless communication apparatus having such a configuration is the same as that of the sixth to eighth embodiments except that power control is performed.

However, the power control is an open-loop power control, a closed-loop power control, or a power control that combines the two.

As described above, CDMA according to Embodiment 9
According to the wireless communication system including the wireless communication device, the reception quality can be further improved by using power control for fluctuations such as fading in the sixth to eighth embodiments.

In the ninth embodiment, the performance is improved by applying power control to the eighth embodiment.
It can be applied to any of the configurations of the sixth to eighth embodiments, and their reception quality can be improved.

(Embodiment 10) FIG.20 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 10 of the present invention.

In the transmitter, transmission data 1301 is subjected to spreading processing in spreading section 1302 and then to chip interleaving processing in chip interleaving section 1307. The interleaved signal is modulated by modulator 1303, amplified by transmission amplifier 1304, and radiated from transmission antenna 1305.

In the receiver, the signal received by receiving antenna 1311 is detected by detecting section 1312, and chip deinterleaving section 1317 rearranges the signal in the reverse order of the chip interleaving for transmission. The deinterleaved data is combined by the despreading unit 1313 to obtain received signal data 1314.

Further, the reception data 1314 is supplied to a synchronization detection unit 1316 where the arrival time of the signal and the frame quality detection unit 190 are detected.
The measurement of frame quality is performed in step 1, and the transmission start time of all users is cut off by the transmission power control unit 2001, which generates a control signal for delaying the transmission start time of the user having no difference in the arrival time. Generate a transmission power control signal and a power control signal.

At this time, based on the frame quality detection result,
If the time required to satisfy the required frame quality is shorter than the limited transmission time length, the reception is performed with excessive quality. Therefore, as shown in FIG. I do.

As a result, interference with other users is reduced, and the total transmission power of the mobile station (transmitter) is also reduced, so that battery saving can be achieved. The operation of the CDMA wireless communication apparatus having such a configuration is the same as that of the sixth to ninth embodiments except that transmission is cut off.

As described above, the CDM according to the tenth embodiment
According to the wireless communication system including the wireless communication device A, the transmission is stopped when the required frame quality is satisfied in the sixth to ninth embodiments, thereby reducing interference with other users and suppressing the total transmission power. Battery saving of the mobile station can be achieved.

In the tenth embodiment, transmission is discarded in the ninth embodiment.
9 can be applied, and reduction in interference with other users and reduction in power consumption of the mobile station can be expected.

(Embodiment 11) FIG.22 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 11 of the present invention.

In FIG. 22, components other than likelihood estimating section 2201 and maximum ratio despreading section 2202 are the same as those in the tenth embodiment.

Transmission data 1301 is spread by spreading section 1302 and chip interleaved by chip interleaving section 1307. The interleaved signal is applied to the modulator 130
3 is amplified by the transmission amplifier 1304 and radiated from the transmission antenna 1305.

In the receiver, the signal received by the receiving antenna 1311 is detected by the detector 1312, the chip deinterleaver 1317 performs the reverse of the transmission interleaving, and then combines by the maximum ratio despreader 2202. Received data 1314 is obtained.

The maximum ratio despreading unit 2202 performs the likelihood estimation
Based on the likelihood estimated from the signal after chip deinterleaving by 201, weighting is performed and then combined.

As a result, S / N can be obtained more than simply combining, and good received data 1314 can be obtained. Further, from the received data 1314, the arrival time is detected by the synchronization detection unit 1316, and the frame quality is detected by the frame quality detection unit 1901. According to the detection, the transmission start time of all user power control transmissions is determined by the transmission power control unit 2001. A control signal for length, transmission start time, transmission power and power control is generated and transmitted to the transmission side.

On the basis of this control signal, the transmission power setting section 1306 sets the transmission time length and the transmission power, and the transmission start time setting section 1702 gives a delay to the transmission start time.

As described above, the CDM according to the eleventh embodiment
A, according to the wireless communication system including the wireless communication device, the maximum ratio despreading unit 220 based on the likelihood estimated from the signal after chip deinterleaving by the likelihood estimation unit 2201.
Since the reception data 1314 is obtained by combining the data after weighting by 2, the S / N can be increased as compared with the case of simply combining, and good reception data 1314 can be obtained.

The eleventh embodiment is different from the tenth embodiment.
Maximum ratio despreading unit 2202 and likelihood estimating unit 2201
However, the present invention can be applied to any of the configurations of the sixth to tenth embodiments to improve the reception quality thereof.

[0148]

According to the present invention, it is possible to solve the problem that the desired quality is not satisfied even if there is a spreading gain, when the quality of all the spread chips similarly deteriorates due to fading, shadowing, or the like. . In addition, the total transmission power can be reduced, and the capacity of the system can be improved. The amount of mutual signal interference between a plurality of users, which is the root of limiting the capacity of CDMA, can be reduced as compared with the conventional method, thereby increasing the capacity and saving the battery of the mobile station. Further, in the TDD system, the guard time can be reduced and the cell radius can be increased.

[Brief description of the drawings]

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

FIG. 2 is a layout diagram of chips interleaved in the CDMA wireless communication apparatus according to the first embodiment.

FIG. 3 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 2 of the present invention.

FIG. 4 is an operation explanatory diagram showing reception quality of the CDMA wireless communication apparatus according to the second embodiment.

FIG. 5 is an operation explanatory diagram showing an interference amount of the CDMA wireless communication apparatus according to the second embodiment.

FIG. 6 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 3 of the present invention.

FIG. 7 is an operation explanatory diagram showing reception quality of the CDMA wireless communication apparatus according to the third embodiment.

FIG. 8 is an operation explanatory diagram showing an interference amount of the CDMA wireless communication apparatus according to the third embodiment.

FIG. 9 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 4 of the present invention.

FIG. 10 is an operation explanatory diagram showing the reception quality of the CDMA wireless communication apparatus according to the fourth embodiment.

FIG. 11 is an operation explanatory diagram showing the amount of interference of the CDMA wireless communication apparatus according to Embodiment 4;

FIG. 12 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 5 of the present invention.

FIG. 13 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 6 of the present invention.

FIG. 14 is an explanatory diagram of the operation of the CDMA radio communication apparatus according to the sixth embodiment.

FIG. 15 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 7 of the present invention.

FIG. 16 is an explanatory diagram of the operation of the CDMA wireless communication apparatus according to the seventh embodiment.

FIG. 17 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 8 of the present invention.

FIG. 18 is an explanatory diagram of the operation of the CDMA wireless communication apparatus according to the eighth embodiment.

FIG. 19 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 9 of the present invention.

FIG. 20 is a block diagram showing a configuration of a CDMA wireless communication apparatus according to Embodiment 10 of the present invention.

FIG. 21 is an explanatory diagram of the operation of the CDMA radio communication apparatus according to the tenth embodiment.

FIG. 22 is a block diagram showing a configuration of a CDMA radio communication apparatus according to Embodiment 11 of the present invention.

FIG. 23 is a block diagram showing a configuration of a conventional CDMA wireless communication device.

FIG. 24 is a layout view of chips subjected to spreading processing in a conventional CDMA wireless communication apparatus.

FIG. 25 is an operation explanatory diagram showing the reception quality of a conventional CDMA wireless communication device.

FIG. 26 is an operation explanatory diagram showing the amount of interference of the conventional CDMA wireless communication device;

[Explanation of symbols]

 102 Spreading unit 106 High-speed transmission power setting unit 107 Chip interleaving unit 113 Despreading unit 115 High-speed transmission power control unit 116 Slot quality detection unit 306 Low-speed transmission power setting unit 315 Low-speed transmission power control unit 606 Transmission power attenuation setting unit 615 Transmission power attenuation Control unit 906 Reverse transmission power setting unit 915 Reverse transmission power control unit 1213 Maximum ratio despreading unit 1218 Likelihood estimation unit

Claims (18)

[Claims] 1. A transmitting apparatus comprising: spreading means for spreading transmission data at a predetermined spreading factor; chip interleaving means for performing a chip interleaving process on the spread transmission data; and a transmission device comprising transmission means for transmitting the transmission data. CDMA radio communication system, comprising: a receiving means for receiving transmission data subjected to chip interleaving processing; and a receiving apparatus including chip deinterleaving means for performing deinterleaving processing on received data for each chip. . 2. The CDMA wireless communication system according to claim 1, wherein low-speed transmission power control is performed to follow a relatively slow change in propagation path conditions. 3. The reception device according to claim 1, further comprising a quality detection unit configured to detect a quality of the received data, wherein the transmission power is attenuated based on a detection result of the quality detection unit. A CDMA wireless communication system as described. 4. The CDMA wireless communication system according to claim 3, wherein the transmission power is attenuated when the quality of the received data exceeds a threshold. 5. The transmission power according to claim 1, wherein the transmission power is controlled to increase the transmission power when the propagation path condition is good, and to reduce the transmission power when the propagation path condition is bad. A CDMA wireless communication system according to any one of claims 1 to 3. 6. The CDMA according to claim 1, wherein the receiving apparatus includes likelihood estimating means for performing likelihood estimation on the data subjected to the chip deinterleaving processing. Wireless communication system. 7. A receiving apparatus, comprising: a synchronization detecting means for measuring an arrival time of received data; and a transmitting apparatus having a slow arrival time, so that reception is completed within a specified time and total transmission power is constant. 2. The CDMA wireless communication system according to claim 1, further comprising: transmission power control means for controlling transmission time length and increasing transmission power. 8. The transmission power control means is configured to complete reception of a transmission signal of a transmission device which is received first by a reception device before a transmission signal of another transmission device which is received later is received. The CDMA wireless communication system according to claim 7, wherein the transmission time length is controlled. 9. The transmission power control means performs control for delaying a transmission start time of a desired transmission device when there is no difference in arrival times of received data from a plurality of transmission devices. The CDMA wireless communication system according to claim 7. 10. The apparatus according to claim 7, further comprising detecting means for detecting the quality of the received data, wherein the transmission power control means controls the transmission power of the transmitting device according to the detected quality of the received data. C according to any of claims 9 to 9
DMA wireless communication system. 11. The transmission power control means controls the transmission device to terminate transmission after the quality of received data detected by the detection means satisfies a required frame quality. The CDMA wireless communication system according to any one of claims 10 to 10. 12. A receiving apparatus, comprising: a likelihood estimating means for estimating likelihood of data subjected to chip deinterleaving processing; and weighting the data based on the estimated likelihood and combining the data. The CDMA according to any one of claims 7 to 11, further comprising:
Wireless communication system. 13. A communication terminal device used in the CDMA wireless communication system according to claim 1. Description: 14. A base station apparatus used in the CDMA wireless communication system according to claim 1. Description: 15. After performing chip interleaving processing on data spread at a predetermined spreading factor, the data is transmitted, and deinterleaving processing is performed on received chip interleaved data for each chip. A CDMA wireless communication method, wherein despreading processing is performed later. 16. The method according to claim 1, wherein low-speed transmission power control is performed to follow a relatively slow change in propagation path conditions.
6. The CDMA wireless communication method according to 5. 17. The CDMA wireless communication method according to claim 15, wherein the quality of data is detected, and the transmission power is attenuated based on a result of the detection. 18. The system according to claim 15, wherein the transmission power is controlled to increase the transmission power when the propagation path condition is good, and to reduce the transmission power when the propagation condition is poor.
18. The CDMA wireless communication method according to claim 17.