JP2002237795A - Radio communication equipment and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drop in frequency use efficiency and transmission efficiency even when level fluctuation respectively independent for every carrier wave is received by the influence of fading, etc., due to multi-path in radio communication by combining a multi-carrier modulation system and a CDMA system. SOLUTION: In dividing parts 104a1 to 104ak, transmission levels of signals to be allocated to each of the carrier waves #1 to #k are divided by reception levels detected by reception level detecting parts 111a1 to 111ak. Thus, the transmission level of the carrier wave with lower reception level preliminarily becomes higher and on the contrary, the transmission level of the carrier wave with higher reception level preliminarily becomes lower. Thus, level control to show opposite characteristics to line characteristics of a transmission line is preliminarily performed by every carrier wave before transmission of the respective carrier waves by using the reception levels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication device used in a digital communication system, and more particularly to an OFD.
Multicarrier modulation methods such as M (Orthogonal Frequency Division Multiplexing) modulation method and CDMA (Code D
The present invention relates to a wireless communication device and a wireless communication method for performing wireless communication in combination with an ivision multiple access (ivision multiple access) method.

[0002]

2. Description of the Related Art In recent years, a multi-carrier modulation scheme such as an OFDM modulation scheme has attracted attention as a modulation scheme for improving frequency use efficiency. Among the multicarrier modulation schemes, the OFDM modulation scheme is a modulation scheme having the highest frequency use efficiency. In this OFDM modulation method, since a plurality of carriers (subcarriers) on which transmission signals are arranged are orthogonal to each other, it is possible to improve the frequency use efficiency. In such an OFDM modulation system, a transmission signal is allocated to a plurality of carriers and a multi-carrier signal (O
FDM signal).

[0003] Hereinafter, a conventional wireless communication apparatus of the OFDM-CDMA system in which the OFDM system and the CDMA system are combined will be described with reference to FIG. Figure 1
FIG. 8 is a block diagram showing a configuration of a conventional wireless communication device.

[0004] In the transmission system of the wireless communication apparatus shown in FIG. 18, n pieces transmission signal of the transmission signal 1 transmitted signal n is the respective spreading sections 11a ₁ ~ spreading section 11a _n, spreading code 1
~ Spreading process using spreading code n. The spreading ratio of each spreading code is k.

[0005] The n transmission signals subjected to the spreading process are code division multiplexed by the adder 12. The code division multiplexed signal is converted by a serial / parallel converter (hereinafter, referred to as “S / P”) 13 into a plurality of series of signals. That is, here, the code division multiplexed signal is divided into the first chip to the k-th chip of the spread code for each chip. First
The signals of a plurality of streams from the chip to the k-th chip are
4

The IFFT section 14 performs an inverse Fourier transform (IFFT) process on a plurality of series of signals. That is, the signals of the first to k-th chips are respectively arranged on k carrier waves prepared for the spreading ratio k. As a result, the signals of the first to k-th chips are frequency-division multiplexed to generate a multicarrier signal.

More specifically, as shown in FIG. 19, carrier # 1 includes code-division multiplexed transmission signals 1 to n
And the k-th chip of the code division multiplexed transmission signals 1 to n is arranged on the carrier wave #k.

In FIG. 18, the signal after the IFFT processing is
That is, the frequency division multiplexed multicarrier signal is
The wireless transmission unit 15 performs predetermined wireless processing such as up-conversion and power amplification. Then, the multicarrier signal after the radio processing is transmitted to a communication partner via the antenna 16.

On the other hand, the multicarrier signal transmitted by the communication partner is received by the wireless communication device shown in FIG. In the receiving system, the multicarrier signal received via the antenna 16 is down-converted or AGC (Auto Gain
Control) is performed.

[0010] The FFT section 18 performs Fourier transform (FFT) processing on the multi-carrier signal after the radio processing, so that signals transmitted by the respective carrier waves # 1 to #k are extracted. The signals transmitted by the respective carrier waves are respectively transmitted from the transmission path compensating section 19a ₁ to the transmission path compensating section 19
After the phase variation or the like generated in the transmission path is compensated by a _k , the signal is input to a parallel / serial conversion unit (hereinafter, referred to as “P / S unit”) 20.

In the P / S section 20, the transmission path compensating section 19a ₁
It signals a plurality of sequences from-channel compensation unit 19a _k is converted to a sequence of signals. Here, at time t ₁ , the signal from transmission path compensator 19a ₁ , that is, the first chip of transmission signal 1 to transmission signal n code-division multiplexed on the communication partner side is output, and at time t _k the signal from the channel compensation unit 19a _k, i.e., the k-th chip of the code division multiplexed transmission signal 1 transmitted signal n is outputted by the communication partner.

The signals output from P / S section 20 are subjected to despreading processing by despreading sections 21a ₁ to 21an using spreading codes 1 to _n , respectively. As a result, each of the despreading units 21a ₁ ~ despreading section 21a _n, and output demodulated signal 1 demodulated signal n.

[0013]

However, the above-mentioned conventional wireless communication apparatus has the following problems.
That is, the level of the multicarrier signal transmitted from the antenna 16 is affected by fading or the like in a transmission path in a multipath environment. That is, the receiving level of the multicarrier signal is not constant on the communication partner side. Further, the multicarrier signal undergoes independent level fluctuation for each carrier. Therefore, FIG.
As shown by 0, the reception level is not uniform among the carriers, and a deviation of the reception level occurs.

In the above conventional radio communication apparatus, carrier # 1
, The first chip of the code division multiplexed transmission signals 1 to n is arranged, and the carrier #k is arranged with the k th chip of the code division multiplexed transmission signals 1 to n. You. That is, focusing on a certain transmission signal, the first chip to the k-th chip of the transmission signal are divided into carrier waves # 1 to #k, respectively, and are arranged. Therefore, the fact that the reception level is not uniform between the carriers means that the reception level is not uniform between the chips.
It turns out that. That is, there is a deviation in the reception level between the chips.

If the reception level is not uniform among the chips as described above, the orthogonality between spreading codes spreading each transmission signal is lost, as described later. If the orthogonality between the spreading codes is broken, mutual interference occurs between the spreading codes, so that the number of signals that can be multiplexed by code division multiplexing decreases, and the frequency use efficiency and the transmission efficiency decrease. is there.

For example, when the cross-correlation between the spreading codes of the transmission signal 1 and the transmission signal 2 which are spread (spread by 4) at the spreading ratio of 4 is obtained, the following is obtained. Here, the spreading code 1 spreading the transmission signal 1 is denoted by '+1, -1,-.
1, +1 ', the spreading code 2 spreading the transmission signal 2
As '+1, -1, +1, -1'.

When the multicarrier signal does not undergo level fluctuations in the transmission path, that is, when the reception level is uniform between chips, the cross-correlation value is as follows. Cross-correlation value = (+ 1) × (+1) + (− 1) × (−
1) + (− 1) × (+1) + (+ 1) × (−1) = 0 When the cross-correlation becomes 0 as described above, the two spreading codes are orthogonal to each other. No interference occurs between them.

However, when the multicarrier signal undergoes level fluctuations in the transmission path, that is, when the reception level is not uniform among the chips, the cross-correlation value is as follows. Here, the transmission signal 2 undergoes a level change, and the spreading code 2 becomes' +2, -3, +
Consider a case where the transmission signal 2 having become 0.1, -0.2 'is received by the receiving system. Cross-correlation value = (+ 1) × (+2) + (− 1) × (−
3) + (− 1) × (+0.1) + (+ 1) × (−0.2)
= + 4.7 When the absolute value of the cross-correlation is no longer 0,
The orthogonality between the spreading codes is broken, and mutual interference occurs between the spreading codes. For this reason, the number of signals that can be multiplexed by code division multiplexing is reduced. As the absolute value of the cross-correlation increases, the interference generated between the spreading codes increases.

As described above, in the above-described conventional radio communication apparatus, there is a problem that when a reception level deviation occurs between carriers due to fading or the like, frequency utilization efficiency and transmission efficiency are reduced.

It should be noted that a plurality of carriers are used in a multi-carrier modulation method other than the OFDM modulation method.
Therefore, in any multi-carrier modulation scheme,
Problems similar to the above can occur.

The above-mentioned problem is a problem peculiar to wireless communication combining a multicarrier modulation system and a CDMA system. That is, in a simple multi-carrier modulation method that does not use the CDMA method, a single carrier does not include a plurality of transmission signals. That is, one transmission signal is not divided for each chip and assigned to a plurality of carriers. Therefore, in a simple multi-carrier modulation method that does not use the CDMA method, the problem of a decrease in transmission efficiency due to a difference in reception level between carriers cannot occur.

The present invention has been made in view of such a point, and in wireless communication combining a multicarrier modulation method and a CDMA method, level fluctuations independent of each carrier due to the effects of multipath fading and the like. It is an object of the present invention to provide a wireless communication device and a wireless communication method that can prevent the frequency use efficiency and the transmission efficiency from being reduced even when receiving.

[0023]

A radio communication apparatus according to the present invention is a radio communication apparatus used in a TDD communication system, and performs a spreading process on a plurality of transmission signals using different spreading codes. Spreading means for applying, first multiplexing means for code division multiplexing the transmission signal after the spreading processing,
Division means for dividing the signal after code division multiplexing for each chip, second multiplexing means for generating a multicarrier signal by allocating a signal for each chip to a different carrier and performing frequency division multiplexing, A configuration is provided that includes a level control unit that performs transmission level control for each carrier so as to have characteristics opposite to the level fluctuation applied to the multicarrier signal, and a transmission unit that transmits the multicarrier signal.

According to this configuration, level control is performed for each carrier in advance before transmitting each carrier, so that the reception level of each carrier is uniform at the communication partner side. become. Therefore, it is possible to prevent the orthogonality between the spreading codes from being broken, and as a result, it is possible to prevent the number of signals that can be multiplexed by code division multiplexing from being reduced. Therefore, even when the multicarrier signal undergoes independent level fluctuations for each carrier due to the effects of multipath fading or the like, it is possible to prevent the frequency use efficiency and the transmission efficiency from decreasing.

The radio communication apparatus according to the present invention includes a receiving means for receiving a multicarrier signal transmitted from a communication partner via a receiving line, and a detecting means for detecting a reception level of each carrier of the multicarrier signal. Then, a configuration is adopted in which the level control means predicts a level fluctuation applied on the transmission line from the reception level.

According to this configuration, since the level fluctuation applied on the transmission line is predicted from the reception level, the level fluctuation can be easily predicted.

The radio communication apparatus according to the present invention employs a configuration in which the level control means lowers the transmission level for a carrier having a higher reception level detected by the detection means, and increases the transmission level for a carrier having a lower reception level.

According to this configuration, since the transmission level control is performed using the reception level, the transmission level control can be easily performed.

The radio communication apparatus according to the present invention includes a correction means for correcting an error commonly included in the reception levels of the respective carriers by dividing the reception level of each carrier by the average value of the reception levels of all the carriers. The level control means performs transmission level control using the reception level after error correction.

According to this configuration, the reception level of each carrier is divided by the average value of the reception levels of all the carriers to correct the error in the reception level of each carrier caused by the AGC error. And an increase in peak power can be prevented.

The radio communication apparatus according to the present invention includes averaging means for obtaining an average value of the reception level in a predetermined section for each carrier, and wherein the level control means performs transmission level control using the average value. Take.

According to this configuration, since the transmission level is controlled using the average value of the predetermined section, even if the signal-to-noise power ratio of the multicarrier signal is temporarily reduced, accurate transmission is performed. Level control can be performed.

[0033] The wireless communication apparatus of the present invention employs a configuration in which the level control means sets the transmission level of each carrier to a predetermined upper limit or less.

According to this configuration, since the transmission level of each carrier, which is increased by the transmission level control, is equal to or lower than the predetermined upper limit, the peak power can be reduced.

The radio communication apparatus of the present invention employs a configuration in which the level control means lowers the predetermined upper limit as the line quality becomes better.

According to this configuration, since the upper limit of the transmission level is adaptively changed according to the line quality, the error rate characteristic and the peak power can be adjusted according to the change in the line quality. That is, according to this configuration, even when the line quality fluctuates, it is possible to reduce the peak power while obtaining a desired error rate characteristic.

The radio communication apparatus according to the present invention employs a configuration in which the level control means increases the predetermined upper limit as the interval between the time slots of the reception line and the transmission line increases.

According to this configuration, the upper limit value of the transmission level is adaptively changed according to the length of the interval between time slots, and when the interval between time slots is long, the transmission level is independent of the line quality. Since the upper limit is set higher, it is possible to prevent the transmission efficiency from decreasing when the time slot interval is long.

[0039] The radio communication apparatus of the present invention employs a configuration in which the level control means sets a predetermined upper limit to be higher when transmitting a signal for a channel signal requiring higher quality.

According to this configuration, when the channel of the transmission signal is a channel requiring high quality, the upper limit of the transmission level is set to a higher value. It is possible to perform transmission level control that satisfies certain requirements.

The radio communication apparatus according to the present invention employs a configuration in which the level control means increases the predetermined upper limit as the number of code division multiplexes of the transmission signal increases.

According to this configuration, since the upper limit of the transmission level is adaptively changed according to the code division multiplex number of the transmission signal, the error rate characteristic and the peak power are changed according to the code division multiplex number of the transmission signal. Can be adjusted. That is, according to this configuration, even when the number of code division multiplexes of a transmission signal changes, peak power can be reduced while obtaining a desired error rate characteristic.

The radio communication apparatus according to the present invention employs a configuration in which the level control means sets the transmission level of each carrier to be equal to or higher than a predetermined lower limit and equal to or lower than a predetermined upper limit.

According to this configuration, since the transmission level of each carrier after the transmission level control falls within a predetermined range, a decrease in transmission efficiency caused by a difference between the transmission line characteristics of the reception line and the transmission line characteristics is prevented. Can be suppressed.

In the wireless communication apparatus according to the present invention, when the level control means detects that the reception level of each carrier detected by the detection means is lower than the average value of the reception levels of all the carriers, the level control means controls the transmission level using the average value. Is adopted.

According to this configuration, the transmission level of each carrier after the transmission level control is all lower than the transmission level when the level control is not performed (conventional), so that the transmission level is lower than when the level control is not performed (conventional). Peak power can be reliably reduced.

In the radio communication apparatus according to the present invention, the level control means sets the transmission level of the carrier corresponding to the reception level to 0 when the reception level detected by the detection means is lower than a predetermined threshold value. Take.

According to this configuration, since the transmission level of the carrier whose reception level has dropped significantly is set to 0, the peak power can be reduced without lowering the transmission efficiency in a strong fading environment.

[0049] The wireless communication apparatus of the present invention employs a configuration in which the level control means increases the predetermined threshold value as the line quality is better.

According to this configuration, the threshold of the reception level is adaptively changed according to the line quality, and the transmission level becomes 0.
, The error rate characteristic and the peak power can be adjusted according to the fluctuation of the channel quality. That is, according to this configuration, even when the line quality fluctuates, it is possible to reduce the peak power while obtaining a desired error rate characteristic.

The radio communication apparatus according to the present invention employs a configuration in which the level control means lowers the predetermined threshold value as the interval between the time slots of the reception line and the transmission line becomes longer.

According to this configuration, the number of carriers whose transmission level is set to 0 is changed according to the length of the interval between time slots, so that the transmission efficiency can be improved when the time slot interval is long.

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

According to these configurations, since the communication terminal device or the base station device is equipped with any of the above radio communication devices, the same effect as described above is exhibited in the communication terminal device or the base station device.

The wireless communication method of the present invention is a wireless communication method used in a TDD communication system,
Transmission level control is performed for each carrier with respect to the code division multiplexed and frequency division multiplexed multicarrier signal so that the transmission level control has characteristics opposite to the level fluctuation applied to the multicarrier signal in the transmission line.

According to this method, level control is performed in advance for each carrier before transmitting each carrier, so that the reception level of each carrier is uniform at the communication partner side. become. Therefore, it is possible to prevent the orthogonality between the spreading codes from being broken, and as a result, it is possible to prevent the number of signals that can be multiplexed by code division multiplexing from being reduced. Therefore, even when the multicarrier signal undergoes independent level fluctuations for each carrier due to the effects of multipath fading or the like, it is possible to prevent the frequency use efficiency and the transmission efficiency from decreasing.

According to the radio communication method of the present invention, a reception level of a multicarrier signal transmitted from a communication partner via a reception line is detected for each carrier, and a level fluctuation applied to the transmission line is predicted from the reception level. I made it.

According to this method, since the level fluctuation applied on the transmission line is predicted from the reception level, the level fluctuation can be easily predicted.

In the radio communication method according to the present invention, the transmission level is set lower for a carrier having a higher reception level, and the transmission level is set higher for a carrier having a lower reception level.

According to this method, since the transmission level control is performed using the reception level, the transmission level control can be easily performed.

DETAILED DESCRIPTION OF THE INVENTION The inventor of the present invention has proposed that an access system in a digital communication system uses TDD (TiD) in which the same frequency band is allocated to a reception line and a transmission line in a time-division manner.
In the case of the me Division Duplex (time division multiplexing) method, paying attention to the fact that the transmission line characteristics of the reception line become the same as the transmission line characteristics of the transmission line, each carrier of the multicarrier signal received via the reception line It has been found that it is possible to predict the level fluctuation applied to the transmission line from the reception level of the present invention, and the present invention has been made.

The gist of the present invention is to perform level control in such a manner as to have the opposite characteristic to the level fluctuation applied in the transmission line for each carrier before transmitting each carrier wave so that the level fluctuation applied in the transmission line is canceled. Thus, the receiving level of each carrier at the communication partner side is made uniform. That is, in the present invention, a carrier having a lower reception level is transmitted with a higher transmission level in advance, and conversely, a carrier having a higher reception level is transmitted with a lower transmission level being transmitted in advance.
The reception level of each carrier was made uniform.

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

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 1 of the present invention. In the following description, an OFDM modulation scheme is taken as an example of a multi-carrier modulation scheme, and an OFDM-CDMA wireless communication apparatus that combines the OFDM scheme and the CDMA scheme will be described.

In the transmission system of the radio communication apparatus shown in FIG. 1, n transmission signals of transmission signal 1 to transmission signal n are subjected to spreading codes 1 to _n by spreading sections 101a ₁ to 101an, respectively. Diffusion processing. The spreading ratio of each spreading code is k.

The n transmission signals subjected to the spreading processing are code division multiplexed by the adder 102. The code division multiplexed signal is converted by the S / P section 103 into a plurality of series of signals. That is, here, the code division multiplexed signal is
The spread code is divided into a first chip to a k-th chip for each chip. Signals a plurality of sequences of the first chip-k th chip respectively, and sent to division section 104a _1-divider 104a _k.

In the division units 104a ₁ to 104a _k ,
Transmission level of the first chip-k-th chip of the signal, respectively, are divided by the coefficient output from the reception level detecting unit 111a _1-reception level detecting unit 111a _k to be described later. Thus, independent transmission level control is performed for each chip, that is, for each carrier. The signals of the first chip to the k-th chip after the transmission level control are transmitted to the IFFT unit 1 respectively.
05.

In IFFT section 105, an inverse Fourier transform (IFFT) process is performed on a plurality of series of signals. That is, the signals of the first to k-th chips are respectively arranged on k carrier waves prepared for the spreading ratio k. As a result, the signals of the first to k-th chips are frequency-division multiplexed to generate a multicarrier signal. The frequency-division multiplexed multicarrier signal is transmitted to the radio transmitting unit 10
After being subjected to predetermined radio processing such as up-conversion and power amplification by 6, it is transmitted to the communication partner via the antenna 107.

On the other hand, the multicarrier signal transmitted by the communication partner is received by the wireless communication apparatus shown in FIG. In the receiving system, the multicarrier signal received via the antenna 107 is down-converted or AGC (Auto G
ain Control) is performed.

The FFT section 109 performs a Fourier transform (FFT) process on the multi-carrier signal after the radio processing, thereby extracting a signal transmitted by each carrier. After each signal is transmitted, the phase fluctuation occurring in the transmission path by the channel compensation unit 110a ₁ ~ channel compensation unit 110a _k is compensated by each carrier, the reception level detecting unit 111a ₁ ~ reception level detecting unit 111a _k and input to the P / S unit 112.

The reception level detectors 111a ₁ to 111a _k detect the reception level of each carrier, and calculate a transmission level control coefficient for each carrier from the detected reception level. Each coefficient for transmission level control is input to the division unit 104a ₁ ~ divider 104a _k.

In P / S section 112, transmission path compensating section 110
It signals a plurality of sequences from a ₁ ~ channel compensation unit 110a _k is,
It is converted into a series of signals. Here, at time t ₁ , the signal from transmission channel compensator 110a ₁ , that is,
The first chip of the code division multiplexed transmission signal 1 transmitted signal n is outputted by the communication partner, at time t _k, the signal from the channel compensation unit 110a _k, i.e., code division multiplexed communication partner K-th of the transmitted transmission signals 1 to n
The chip number is output.

The signal output from P / S section 112 is subjected to despreading processing by despreading sections 113a ₁ to 113an using spreading codes 1 to _n , respectively. As a result, the despreading units 113a ₁ to 113a _n
Output demodulated signals 1 to n, respectively.

Next, the operation of the wireless communication apparatus having the above configuration will be described. First, the operation principle will be described using equations.

A preamble portion of a signal arranged on each carrier of a multicarrier signal transmitted from a communication partner contains a known reference signal for estimating transmission path characteristics.
This known reference signal is a signal having a constant transmission level, and here, for example, the transmission level is set to 1 for simplicity of explanation. Therefore, the known reference signal TX allocated to each carrier of the multicarrier signal transmitted from the communication partner
_k (t) is represented by the following equation (1).

(Equation 1) d _k (t) is a known reference signal before IFFT processing on carrier wave k, N is the number of samples, k = 0, 1, 2,..., t = 0, 1, 2
...

As described above, the multicarrier signal transmitted from the communication partner undergoes independent level fluctuations for each carrier in the transmission path. Further, the multicarrier signal undergoes independent phase fluctuations for each carrier.
The level variation applied to carrier k and A _k (t), the phase fluctuation and _{exp (jΘ k (t))} , a known reference signal RX _k received by the wireless communication apparatus shown in FIG. 1 (t), the following Equation (2) Here, the signal after the FFT processing is shown.

(Equation 2)

As described above, since the transmission level of the known reference signal is constant at 1, the reception level R _k (t) of the known reference signal allocated to each carrier is represented by the following equation (3).

(Equation 3) That is, by detecting the reception level of the known reference signal, it is possible to detect the level fluctuation applied on the transmission path.

Here, as described above, if the access system is the TDD system, the transmission line characteristics of the reception line become the same as the transmission line characteristics of the transmission line. Therefore, it is possible to easily predict the level fluctuation applied to the transmission line from the reception level of each carrier of the multicarrier signal received via the reception line.
Therefore, level control is performed in advance for each carrier before transmission of each carrier, so as to have a characteristic opposite to the level fluctuation applied on the transmission line.

More specifically, the transmission level of the signal allocated to each carrier is changed to the reception level R _k (t) _represented by the above equation (3).
Divide by. In the transmission path, a level fluctuation A _k (t) as shown in the above equation (2) is added, so that the reception level R _k (t)
, The level fluctuation A _k (t) is canceled out, and the reception level of each carrier can be made uniform. That is, the reception level can be made uniform among the chips.

Although the case where the reception level is used as it is as the coefficient for controlling the transmission level has been described, the present invention is not limited to this, and the result of performing a predetermined operation on the reception level is used as the coefficient for controlling the transmission level. It may be a coefficient.
Hereinafter, the same applies.

Next, the operation of the radio communication apparatus based on the above operation principle will be described with reference to FIG. 1 and FIG.
In the radio communication apparatus shown in FIG. 1, a known reference signal for channel estimation which is arranged on each carrier, respectively, is input to the reception level detecting unit 111a ₁ ~ reception level detecting unit 111a _k.

Since the multicarrier signal undergoes independent level fluctuations for each carrier in the transmission path, the reception level is not uniform among the carriers as shown in FIG. 2 (a). Received level detector 11
1a ₁ ~ reception level detecting unit, respectively in 111a _k, the reception level of the known reference signal arranged in each carrier is detected. As a result, the level fluctuation applied on the transmission path is detected. In other words, the transmission path characteristics of the receiving line are detected.

Reception level detection section 111a₁~ Reception level
Detection unit 111a_kAre carrier # 1 to carrier #k, respectively.
Division unit 1 using the reception level of
04a ₁-Division unit 104a_kOutput to Division unit 104a
₁-Division unit 104a_kThen, carrier waves # 1 to #k are
The transmission level of each assigned signal is the reception level
Detection unit 111a₁~ Reception level detection section 111a_kDetected by
Divided by the received level. Thus, the reception level
, Transmission level control can be easily performed.

As a result, a carrier having a lower reception level has a higher transmission level in advance, and a carrier having a higher reception level has a lower transmission level in advance. Therefore, the transmission level of each carrier after the transmission level control is as shown in FIG. If the access method is the TDD method, the transmission line characteristics of the reception line and the transmission line characteristics of the transmission line are the same, and thus the transmission line characteristics are reversed by using the reception level in this manner. Such level control can be performed in advance for each carrier before transmitting each carrier.

In the transmission path (transmission line), FIG.
A level fluctuation of the opposite characteristic to the level control as shown in FIG. 2B (that is, a level fluctuation as shown in FIG. 2A) is applied to each carrier. Therefore, the reception level of each carrier of the multicarrier signal received by the communication partner becomes uniform as shown in FIG.

In this way, the reception level can be made uniform between the chips by making the reception level uniform between the carrier waves. That is, it is possible to prevent the orthogonality between the spreading codes spreading each transmission signal from being broken, and to prevent mutual interference between the spreading codes. Therefore, it is possible to prevent the number of signals that can be multiplexed from being reduced by code division multiplexing.

As described above, according to the present embodiment, when the access system is the TDD system, the level control is performed by using the reception level so that the characteristics are inverse to the transmission line characteristics of the transmission line. Because it is performed for each carrier before transmission,
The receiving level of each carrier becomes uniform on the communication partner side. Therefore, it is possible to prevent the orthogonality between the spreading codes from being broken, and as a result, it is possible to prevent the number of signals that can be multiplexed by code division multiplexing from being reduced. Therefore, according to the present embodiment, the multicarrier signal
Even when each carrier undergoes an independent level change due to the effects of multipath fading or the like, it is possible to prevent the frequency use efficiency and the transmission efficiency from decreasing.

(Embodiment 2) In the present embodiment, a case will be described in Embodiment 1 where deterioration of error rate characteristics and increase in peak power are prevented.

An error may occur in AGC performed by radio receiving section 108. Since the AGC is performed uniformly for all carriers, if the error of the AGC occurs, the reception level detecting unit 111a ₁ ~ reception level detecting unit 111a _k at the reception level detected includes an error by the same uniformly Become like That is, the reception level detecting unit 111a ₁ ~ reception level detecting unit 111a _k at the reception level detected becomes higher or lower uniformly.

As described above, the transmission level is controlled using the reception level as a divisor. For this reason, the transmission level becomes lower as the reception level becomes higher than the correct value. As a result, the reception level at the communication partner side becomes lower than when there is no AGC error. That is, if the reception level becomes higher than the correct value, the signal-to-noise power ratio becomes smaller on the communication partner side, and the error rate characteristics deteriorate.

Conversely, as the reception level becomes lower than the correct value, the transmission level becomes higher. Further, since the peak power of the multicarrier signal is the sum of the powers of all the carriers, the higher the transmission level of each carrier, the larger the peak power of the multicarrier signal. Wireless transmission unit 106
Since power amplification is performed on a multicarrier signal by analog processing, the power consumption increases as the peak power increases. When the wireless communication device is mounted on a mobile communication terminal, an increase in power consumption leads to consumption of a battery, which poses a serious problem in terms of the usage time of the mobile communication terminal.

Therefore, in the present embodiment, the error generated in the AGC is corrected as described below to prevent the error rate characteristic from deteriorating and the peak power from increasing. FIG. 4 is a block diagram illustrating a configuration of the wireless communication device according to the second embodiment of the present invention. In FIG. 4, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

[0092] As shown in FIG. 4, a wireless communication apparatus according to this embodiment, the wireless communication apparatus according to the first embodiment, by adding a further averaging unit 201 and division section 202a ₁ ~ divider 202a _k Take the configuration.

In the averaging section 201, the reception level detecting section 1
The average value of the reception level output from 11a ₁ ~ reception level detecting unit 111a _k is calculated. That is, the average value of the reception levels of all carriers is calculated. The average value of reception levels of all carriers divider 202a ₁ ~ divider 202a _k
Is input to

The division unit 202a₁To division unit 202a_kThen
Each of the reception level detection units 111a ₁~ Reception level detection
Part 111a_kIs received by the averaging unit 20
It is divided by the average of the reception levels calculated in 1. this
The average value is set to the reception level of all carriers due to AGC error.
Includes common errors, so each carrier
By dividing the level by this average, each carrier
An error included in the reception level can be corrected. Yo
Therefore, an error occurs in the AGC performed by the wireless receiving unit 108.
Error also occurs in the transmission level control of each carrier
Can be prevented. That is, the error rate performance is poor.
And increase in peak power can be prevented.

As described above, according to the present embodiment, the error in the reception level of each carrier caused by the AGC error is corrected by dividing the reception level of each carrier by the average value of the reception levels of all the carriers. Therefore, it is possible to prevent the deterioration of the error rate characteristic and the increase of the peak power.

(Embodiment 3) In this embodiment, a case will be described in Embodiment 1 where the accuracy of the transmission level control coefficient is increased.

The signal-to-noise power ratio of the multi-carrier signal temporarily decreases due to the influence of temporary noise or the like, and the reception level detection units 111a ₁ to 111a ₁ to reception level detection unit 1
Temporary reception level detected by 11a _k to have an error may occur. That is, the precision of the transmission level control coefficient may be low, and the precision of the transmission level control may be low.

Therefore, in the present embodiment, the accuracy of the transmission level control coefficient is increased as follows. FIG.
FIG. 9 is a block diagram showing a configuration of a wireless communication device according to a third embodiment of the present invention. In FIG. 5, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

[0099] As shown in FIG. 5, the radio communication apparatus according to this embodiment, the wireless communication apparatus according to the first embodiment employs a configuration further added an averaging unit 301a ₁ ~ averaging unit 301a _k .

[0100] In the averaging unit 301a ₁ ~ averaging unit 301a _k, the reception level detecting unit 111a ₁ ~ reception level detection unit 1
Average value of the reception level output from 11a _k is calculated for each carrier. That is, the averaging unit 301a _1,
Calculated average value of a predetermined interval of reception levels of carrier # 1, the averaging unit 301a _k, the average value of a predetermined interval of reception levels of carrier #k is calculated. The average values of these predetermined sections are respectively calculated by dividing units 104a ₁ to 104a ₁
output to a _k .

As described above, according to the present embodiment, since the transmission level control is performed using the result of averaging the transmission level control coefficients for a predetermined section, the signal-to-noise power ratio of the multicarrier signal is temporarily reduced. Even if it is low,
Accurate transmission level control can be performed.

(Embodiment 4) In the present embodiment, a case where the peak power is reduced in Embodiment 1 will be described.

When a multicarrier signal undergoes strong fading in the transmission path, the reception level of each carrier may drop significantly. As a result, the transmission level of each carrier whose transmission level is controlled becomes extremely high, and the peak power of the multicarrier signal may become extremely large. As described above, since an increase in peak power leads to an increase in power consumption, it is important to reduce the peak power.

Therefore, in this embodiment, the peak power is reduced as follows. FIG. 6 is a block diagram illustrating a configuration of the wireless communication device according to the fourth embodiment of the present invention. In FIG. 6, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

As shown in FIG. 6, the radio communication apparatus according to the present embodiment differs from the radio communication apparatus according to the first embodiment in that coefficient adjustment sections 401a ₁ to 401a _k are further added.
Is adopted. Further, the coefficient adjustment units 401a ₁ to 401a ₁ to
Structure of the coefficient adjusting unit 401a _k is as shown in FIG. FIG. 7 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication device according to the fourth embodiment of the present invention. In addition,
Since all the coefficient adjusting unit 401a ₁ ~ coefficient adjusting unit 401a _k is the same configuration, will be described here only for the coefficients adjusting unit 401a _1.

[0106] In the coefficient adjusting unit 401a ₁ shown in FIG. 7, the comparison unit 501, and the reception level of the carrier wave # 1 output from the reception level detecting unit 111a _1, and the lower limit value of the reception level is compared, the comparison result Is output to the selection unit 502.

[0107] In the selector 502, in accordance with a signal indicating the comparison result, one of the reception level output from the lower limit value or the reception level detecting unit 111a ₁ is selected and output to the division unit 104a _1. That is, when the reception level output from the reception level detecting unit 111a ₁ is lower than the lower limit value is selected lower limit, conversely, the reception level output from the reception level detecting unit 111a ₁ is in the case of less than the lower limit the reception level output from the reception level detecting unit 111a ₁ is selected.

[0108] By such a comparison selection is made, the always lower limit value greater than the reception level to be used as a divisor in a division unit 104a _1. Therefore, the transmission level of the carrier wave # 1 which is increased by the transmission level control is always equal to or less than a predetermined value (one time lower than the lower limit when the level control is not performed). That is, even when the reception level of each carrier drops significantly, the transmission level of each carrier, which is increased by the transmission level control, is equal to or lower than a predetermined value.

As described above, according to the present embodiment, since the transmission level of each carrier increased by the transmission level control is equal to or lower than the predetermined upper limit, the peak power can be reduced as compared with the first embodiment. it can.

In the present embodiment, since the transmission level of each carrier, which is increased by the transmission level control, is forcibly set to a predetermined value or less, a slight deviation occurs in the reception level between the carriers on the communication partner side. . Therefore, in the present embodiment, the transmission efficiency is slightly lower than in Embodiment 1 in which the lower limit is not set.

However, even if the lower limit is set, the deviation of the reception level between the carrier waves can be significantly reduced as compared with the above-mentioned conventional radio communication apparatus, so that the transmission efficiency can be significantly improved as compared with the conventional one. be able to.
Therefore, the present embodiment is effective when it is desired to increase the transmission efficiency while reducing the peak power.

(Embodiment 5) In this embodiment, a case will be described in which Embodiment 1 suppresses a decrease in transmission efficiency caused by a difference between the transmission line characteristics of the reception line and the transmission line characteristics.

In the TDD system, the difference between the transmission line characteristics of the reception line and the transmission line increases as the interval between the time slots of the reception line and the transmission line (hereinafter, simply referred to as “time slot interval”) increases. In this case, it becomes impossible to perform level control for each carrier so as to completely reverse the transmission path characteristics of the transmission line. That is, a carrier wave whose transmission level is higher or lower than the original transmission level (the transmission level when the transmission path characteristic of the receiving line is the same as the transmission path characteristic of the transmission line) occurs. The greater the difference from the original transmission level, the greater the deviation of the reception level between the carriers on the communication partner side, and the lower the transmission efficiency.

Therefore, in the present embodiment, a decrease in transmission efficiency caused by a difference between the transmission line characteristics of the reception line and the transmission line characteristics is suppressed as follows. FIG.
FIG. 13 is a block diagram illustrating a configuration of a coefficient adjustment unit of a wireless communication device according to a fifth embodiment of the present invention. Since the configuration other than the internal configuration of the coefficient adjustment unit is the same as the configuration shown in FIG. 6, only the coefficient adjustment unit will be described here. Further, in FIG. 8, the comparison unit 501 and the selection unit 502 have the same configuration as in the fourth embodiment (FIG. 7), and thus the description is omitted.
Also, because all the coefficient adjusting unit 401a ₁ ~ coefficient adjusting unit 401a _k is the same configuration, the coefficient adjusting unit 401 here
a description will be given only a _1.

[0115] In the coefficient adjusting unit 401a ₁ shown in FIG. 8, the comparison unit 601, an output (i.e., the reception level or the lower limit thereof of the carrier # 1) from the selector 502
Is compared with the upper limit of the reception level, and a signal indicating the comparison result is output to the selection unit 602.

[0116] In the selector 602, in accordance with a signal indicating the comparison result, one of the outputs from the upper limit value or selection section 502 is selected and output to the division unit 104a _1.
That is, when the output from the selection unit 502 is higher than the upper limit value, the upper limit value is selected, and when the output from the selection unit 502 is equal to or less than the upper limit value, the output from the selection unit 502 is selected.

The comparing section 501, the selecting section 502, and the comparing section 60
Comparison selection made by the 2 and selection unit 602, the division unit 104a ₁ is received level used as the divisor always above the lower limit value, the upper limit value or less of the value. Therefore,
The transmission level of the carrier wave # 1 after the transmission level control always falls within a predetermined range (between the upper limit and the lower limit when the level control is not performed). That is,
The difference between the transmission level of each carrier after the transmission level control and the original transmission level can be kept within a predetermined range.

As described above, according to the present embodiment, in order to keep the transmission level of each carrier after the transmission level control within a predetermined range, the difference between the transmission line characteristics of the reception line and the transmission line characteristics of the transmission line is obtained. , It is possible to suppress a decrease in transmission efficiency caused by the above.

(Embodiment 6) In this embodiment, a case will be described in Embodiment 1 where the peak power is reduced more reliably than in the conventional case.

In the fourth embodiment, the case where the peak power is reduced as compared with the first embodiment has been described. However, in the fourth embodiment, the peak power can be reduced as compared with the first embodiment, but the peak power may be higher than in the related art depending on the setting of the lower limit.

Therefore, in the present embodiment, the peak power is reduced more reliably than in the prior art as follows. FIG.
FIG. 14 is a block diagram showing a configuration of a wireless communication device according to a sixth embodiment of the present invention. In FIG. 9, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

As shown in FIG. 9, the radio communication apparatus according to the present embodiment is different from the radio communication apparatus according to the first embodiment in that an averaging section 201 and a coefficient adjusting section 402a _{1 are} added.
Adopt a configuration obtained by adding the adjustment portion 402a _k ~ factor. In addition,
The averaging section 201 has the same configuration as that of the second embodiment (FIG. 4), and a description thereof will be omitted.

The configuration of the coefficient adjusting units 402a ₁ to 402a _k is as shown in FIG. FIG.
FIG. 14 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication device according to the sixth embodiment of the present invention. Incidentally, because all the coefficient adjusting unit 402a ₁ ~ coefficient adjusting unit 402a _k is the same configuration, will be described here only for the coefficients adjusting unit 402a _1.

[0124] In the coefficient adjusting unit 402a ₁ shown in FIG. 10, the comparison section 701, the average value of the reception levels of all carriers outputted from the averaging unit 201, the reception level detection unit 1
A reception level of the carrier # 1 output from 11a ₁ are compared, a signal indicating the comparison result is output to the selection unit 702.

[0125] In the selector 702, in accordance with a signal indicating the comparison result, is selected one of the reception level output from the average value or the reception level detecting unit 111a ₁ output from the averaging unit 201, the division unit 104a Output to ₁ . That is, the average value of the reception level is selected if the reception level output from the reception level detecting unit 111a ₁ is lower than the average value output from the averaging unit 201, conversely, the output from the reception level detecting unit 111a ₁ reception level output from the reception level detecting unit 111a ₁ is selected if the above average reception level is output from the averaging unit 201.

[0126] By such a comparison selection is made, received level used as a divisor in a division unit 104a ₁ is always an average value or more values output from the averaging unit 201. Therefore, the transmission level of the carrier wave # 1 which is increased by the transmission level control is always lower than the transmission level when the level control is not performed (conventional). That is, the transmission levels of the respective carriers after the transmission level control are all lower than the transmission level when the level control is not performed (conventional). Therefore, peak power is obtained when level control is not performed (conventional).
More reliably.

As described above, according to the present embodiment, since the transmission level of each carrier is equal to or lower than the conventional transmission level, the peak power can be reduced more reliably than before.

In the present embodiment, the peak power can be reduced more reliably than in the prior art, but the reception level deviation between the carriers on the communication partner side is larger than in the fourth embodiment. There is. Therefore, in the present embodiment, the transmission efficiency may be lower than in the fourth embodiment. However, the deviation of the reception level between the carrier waves can be reduced as compared with the above-described conventional wireless communication device, so that the transmission efficiency can be increased as compared with the related art. Therefore, the present embodiment is effective when more emphasis is placed on reducing the peak power.

(Embodiment 7) In this embodiment, a case will be described in Embodiment 4 where the error rate characteristic and the peak power are adjusted according to the fluctuation of the channel quality.

The optimum value of the lower limit of the reception level (that is, the upper limit of the transmission level) differs depending on the line quality. That is, even if the transmission level is lowered as the line quality becomes better, a desired error rate characteristic can be obtained on the communication partner side. Therefore, in this case, the lower limit of the reception level is set higher (the upper limit of the transmission level is set lower),
The peak power can be further reduced. vice versa,
Unless the transmission level is increased as the line quality deteriorates, it becomes difficult for the communication partner to obtain a desired error rate characteristic. Therefore, in this case, it is necessary to set the lower limit of the reception level lower (set the upper limit of the transmission level higher). Thus, the lower limit of the reception level (that is,
The optimum value of the upper limit of the transmission level) varies depending on the line quality.

Therefore, in the present embodiment, the lower limit of the reception level is changed according to the channel quality as follows. FIG. 11 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication device according to the seventh embodiment of the present invention. Since the configuration other than the internal configuration of the coefficient adjustment unit is the same as that of the fourth embodiment (FIG. 6), only the coefficient adjustment unit will be described here. Also, because all the coefficient adjusting unit 401a ₁ ~ coefficient adjusting unit 401a _k is the same configuration, will be described here only for the coefficients adjusting unit 401a _1.

[0132] In the coefficient adjusting unit 401a ₁ shown in FIG. 11, the comparison unit 801, a value indicating the channel quality is input as channel quality information (e.g., signal to interference power ratio)
Is compared with a predetermined threshold value indicating the line quality.
A signal indicating the comparison result is output to selection section 802.

In selecting section 802, either lower limit 1 or lower limit 2 (lower limit 1> lower limit 2) is selected in accordance with the signal indicating the comparison result, and is output to comparing section 803 and selecting section 804. You. That is, when the value indicating the line quality is equal to or more than a predetermined threshold value (when the line quality is good), the lower limit value 1 is selected, and conversely, the value indicating the line quality becomes less than the predetermined threshold value. If this is the case (when the line quality is poor), the lower limit value 2 is selected. That is, if the line quality is good, the lower limit of the reception level is set higher (the upper limit of the transmission level is set lower), and if the line quality is poor, the lower limit of the reception level is set lower. (The upper limit of the transmission level is set higher).

[0134] In the comparison unit 803, the lower limit value output from the selection unit 802 (the lower limit value 1 or lower limit 2), and the reception level of the carrier # 1 output from the reception level detecting unit 111a ₁ are compared, compared The signal indicating the result is selected by the selection unit 804.
Is output to

[0135] In the selector 804, in accordance with a signal indicating the comparison result, one of the reception level output from the lower limit value or the reception level detecting unit 111a ₁ is selected and output to the division unit 104a _1. That is, when the reception level output from the reception level detecting unit 111a ₁ is lower than the lower limit value is selected lower limit, conversely, the reception level output from the reception level detecting unit 111a ₁ is in the case of less than the lower limit the reception level output from the reception level detecting unit 111a ₁ is selected. Therefore, when the line quality is good, the reduction of the peak power is prioritized, and when the line quality is bad, the error rate characteristic is prioritized.

As described above, according to the present embodiment, in order to adaptively change the upper limit of the transmission level according to the line quality, the error rate characteristic and the peak power are adjusted according to the change in the line quality. can do. That is, according to the present embodiment, even when the line quality fluctuates, it is possible to reduce the peak power while obtaining a desired error rate characteristic.

In the above description, two lower limit values are used. However, the present invention is not limited to this, and three or more lower limit values may be used. The same applies to the following embodiments.

(Embodiment 8) In the present embodiment, a case will be described in Embodiment 7 where the transmission efficiency is prevented from being reduced when the time slot interval is long.

As described above, in the TDD system,
As the time slot interval becomes longer, the deviation of the reception level between the carriers increases, and the transmission efficiency decreases. Further, in this case, if the lower limit of the reception level (the upper limit of the transmission level) is set in order to reduce the beak power,
Since the transmission level of each carrier, which is increased by the transmission level control, is forcibly set to a predetermined value or less, the deviation of the reception level between the carriers further increases, and the transmission efficiency further decreases. As the lower limit of the reception level is set higher (the upper limit of the transmission level is set lower), the transmission efficiency is greatly reduced.

Therefore, the present embodiment prevents the transmission efficiency from decreasing when the time slot interval is long, as described below. FIG. 12 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the eighth embodiment of the present invention. Since the configuration other than the internal configuration of the coefficient adjustment unit is the same as the configuration shown in FIG. 6, only the coefficient adjustment unit will be described here. In FIG. 12, the same components as those in the seventh embodiment (FIG. 11) are denoted by the same reference numerals as those in FIG. 11, and detailed description is omitted. Further, the coefficient adjustment units 401a ₁ to 401a _k
Have the same configuration, so here the coefficient adjustment unit 4
A description will be given only 01a _1.

[0141] In the coefficient adjusting unit 401a ₁ shown in FIG. 12, the AND operation unit 805, from the physical layer of the upper layer (hereinafter, simply referred to as. "Upper layer") and a selection signal input from the comparison unit 801 The logical product with the input signal indicating the comparison result is calculated.

In the upper layer, the time slot interval is monitored successively. If this interval is equal to or longer than a predetermined threshold value (when the interval is long), a selection signal '0' indicating this is sent from the upper layer. It is input to the logical product operation unit 805.
Conversely, when this interval is smaller than the predetermined threshold value (when the interval is short), a selection signal '1' indicating that fact is input to the AND operation unit 805 from the upper layer. On the other hand, when the value indicating the line quality is equal to or more than the predetermined threshold (when the line quality is good), signal “1” indicating that fact is input from comparison section 801, and conversely, Is smaller than a predetermined threshold (when the line quality is poor), a signal '0' indicating that is input.

Therefore, in the AND operation section 805, the operation result becomes "1" only when the line quality is good and the time slot interval is short. That is, when the time slot interval is long, the calculation result is always '0' regardless of the line quality. The calculation result is output to the selection unit 802.

In the selecting section 802, either the lower limit 1 or the lower limit 2 (lower limit 1> lower limit 2) is selected according to the operation result in the AND operation section 805. That is, if the operation result of the AND operation unit 805 is “0”, the lower limit value 2 is selected, and if the operation result is “1”, the lower limit value 1 is selected. That is, when the time slot interval is long, the lower limit 2 is always selected regardless of the line quality, and the upper limit of the transmission level is set higher. As a result, it is possible to reduce the deviation of the reception level between the carriers on the communication partner side.

As described above, according to the present embodiment, the upper limit of the transmission level is adaptively changed according to the length of the time slot interval, and when the time slot interval is long, regardless of the line quality. Since the upper limit of the transmission level is set higher, it is possible to prevent the transmission efficiency from decreasing when the time slot interval is long.

(Embodiment 9) In this embodiment, a case will be described in Embodiment 7 where transmission level control is performed according to required quality. That is, in the present embodiment, a case will be described in which transmission level control is performed so as to reliably satisfy the desired essence of a channel requiring high quality.

The level of the lower limit of the reception level (that is, the upper limit of the transmission level) differs depending on the quality required for each channel. That is, for a channel requiring high quality (for example, a control channel, a retransmission channel, or the like), the lower limit of the reception level is set lower than the other channels (the upper limit of the transmission level is set higher), and the desired level is set. There is a need to ensure that the essence is fulfilled.

Therefore, in the present embodiment, transmission level control is performed as described below so as to reliably satisfy the desired essence of a channel requiring high quality. FIG.
FIG. 14 is a block diagram showing a configuration of a coefficient adjustment unit of the wireless communication device according to the ninth embodiment of the present invention. Since the configuration other than the internal configuration of the coefficient adjustment unit is the same as the configuration shown in FIG. 6, only the coefficient adjustment unit will be described here. Also,
13, the same components as those in the seventh embodiment (FIG. 11) are denoted by the same reference numerals as those in FIG. 11, and detailed description will be omitted. Also, because all the coefficient adjusting unit 401a ₁ ~ coefficient adjusting unit 401a _k is the same configuration, will be described here only for the coefficients adjusting unit 401a _1.

[0149] In the coefficient adjusting unit 401a ₁ shown in FIG. 13, the AND operation unit 806, the logic of a channel type signal inputted from the upper layer at the time of signal transmission, a signal indicating the comparison result input from the comparing section 801 The product is calculated. Note that the channel type signal is a signal for indicating whether the channel of the transmission signal is a channel requiring high quality.

Since the upper layer sequentially monitors which channel the transmission signal belongs to, if the channel is a channel for which high quality is required, the higher layer transmits a channel type signal ' 0 ′ is input to the logical product operation unit 806. On the other hand, if the channel is a channel other than the channel for which high quality is required, a selection signal '1' indicating that fact is input to the AND operation unit 806 from the upper layer. On the other hand, when the value indicating the line quality is equal to or more than the predetermined threshold (when the line quality is good), signal “1” indicating that fact is input from comparison section 801, and conversely, Is smaller than a predetermined threshold (when the line quality is poor), a signal '0' indicating that is input.

Therefore, in the AND operation section 806, the operation result becomes "1" only when the channel quality is good and the channel of the transmission signal is a channel other than the channel requiring high quality. In other words, if the channel of the transmission signal is a channel requiring high quality, the operation result is always '0' regardless of the line quality. The calculation result is output to the selection unit 802.

In the selecting section 802, one of the lower limit 1 and the lower limit 2 (lower limit 1> lower limit 2) is selected according to the operation result in the AND operation section 806. That is, if the operation result of the AND operation unit 806 is “0”, the lower limit value 2 is selected, and if the operation result is “1”, the lower limit value 1 is selected. That is, when the channel of the transmission signal is a channel requiring high quality, the lower limit value 2 is always selected regardless of the line quality, and the upper limit value of the transmission level is set higher. By performing transmission level control according to the required quality in this way, the communication partner side can maintain the quality of the channel requiring high quality to be equal to or higher than the desired quality.

As described above, according to the present embodiment, when the channel of a transmission signal is a channel requiring high quality, the upper limit of the transmission level is set higher regardless of the channel quality. It is possible to perform transmission level control that reliably satisfies the desired essence of a channel that requires high quality.

(Embodiment 10) In this embodiment, a case will be described in Embodiment 4 where the error rate characteristic and the peak power are adjusted according to the number of code division multiplexed transmission signals.

The optimum value of the lower limit of the reception level (that is, the upper limit of the transmission level) differs depending on the number of code division multiplexed transmission signals. In other words, the smaller the number of code division multiplexing of transmission signals, the smaller the interference between spreading codes becomes. Therefore, even if the receiving level deviation between each carrier is slightly larger on the communication partner side, it is possible to obtain a desired error rate characteristic. Can be. Therefore, in this case, the lower limit of the reception level is set higher (the upper limit of the transmission level is set lower), so that the peak power can be further reduced. Conversely, as the number of code division multiplexes of a transmission signal increases, the interference generated between spreading codes increases. Therefore, as the number of code division multiplexes increases, the lower limit of the reception level is set lower (the upper limit of the transmission level is set higher). Therefore, it is necessary to reduce the deviation of the reception level between the carriers on the communication partner side. As described above, the optimum value of the lower limit of the reception level (that is, the upper limit of the transmission level) differs depending on the number of code division multiplexed transmission signals.

Therefore, in the present embodiment, the lower limit of the reception level is changed according to the number of code division multiplexing of the transmission signal as follows. FIG. 14 shows Embodiment 1 of the present invention.
FIG. 4 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication apparatus according to FIG. Since the configuration other than the internal configuration of the coefficient adjustment unit is the same as that of the fourth embodiment (FIG. 6), only the coefficient adjustment unit will be described here. In FIG. 14, the same components as those in the seventh embodiment (FIG. 11) are denoted by the same reference numerals as those in FIG. 11, and detailed description will be omitted. Further, the coefficient adjustment units 401a ₁ to 401a _k
Have the same configuration, so here the coefficient adjustment unit 4
A description will be given only 01a _1.

In coefficient adjusting section 401a ₁ shown in FIG. 14, comparing section 901 determines the number of code division multiplexed transmission signals,
The multiplex number is compared with a reference value, and a signal indicating the result of the comparison is output to selection section 902.

In selecting section 902, one of lower limit value 1 and lower limit value 2 (lower limit value 1> lower limit value 2) is selected in accordance with the signal indicating the comparison result, and is output to comparing section 803 and selecting section 804. You. That is, if the code division multiplexing number of the transmission signal is equal to or more than the reference value, the lower limit value 2 is selected. Conversely, if the code division multiplexing number of the transmission signal is less than the reference value, the lower limit value 1 is selected. You. That is, as the number of code division multiplexes of the transmission signal increases, the lower limit of the reception level is set lower (the upper limit of the transmission level is set higher).

As described above, according to the present embodiment, the upper limit of the transmission level is adaptively changed according to the number of code division multiplexes of a transmission signal. The rate characteristics and the peak power can be adjusted. That is, according to the present embodiment, even when the number of code division multiplexes of a transmission signal changes, peak power can be reduced while obtaining a desired error rate characteristic.

(Embodiment 11) In this embodiment, a case will be described in Embodiment 1 where the peak power is reduced without reducing the transmission efficiency in a strong fading environment.

When the multicarrier signal has undergone strong fading in the transmission path, the reception level of each carrier is large (for example, −40 of the average reception level of all carriers).
dB or more). When the reception level drops significantly, the peak power of the multicarrier signal becomes extremely large as described above. In order to prevent this, in Embodiment 4, the lower limit of the reception level (the upper limit of the transmission level) is set.

However, in a strong fading environment, even if the transmission level of the carrier whose reception level has dropped greatly is raised to the upper limit, the reception level on the communication partner side drops significantly after all. The deviation of the reception level between each carrier on the side remains large and hardly changes. Therefore, in such a case, the transmission efficiency cannot be increased even if the transmission level of the carrier whose reception level is greatly lowered is slightly increased. In other words, even if the transmission level of the carrier wave whose reception level is greatly reduced is set to 0, the transmission efficiency hardly decreases.
By setting the transmission level to 0, the peak power can be reduced. Therefore, in such a case,
It is more effective to reduce the peak power by setting the transmission level to 0.

Therefore, in the present embodiment, the peak power is reduced without lowering the transmission efficiency in a strong fading environment as described below. FIG.
FIG. 21 is a block diagram showing a configuration of a wireless communication device according to an eleventh embodiment of the present invention. In FIG. 15, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1, and detailed description is omitted.

[0164] As shown in FIG. 15, the radio communication apparatus according to this embodiment, the wireless communication apparatus according to the first embodiment, further comparison unit 1001a ₁ ~ comparator unit 1001a _k, the selection unit 1002a ₁ ~ selector It takes a configuration obtained by adding the 1002a _k. Incidentally, all comparator unit 1001a ₁ ~ comparator unit 1001a _k becomes the same configuration, also, the selection unit 1002a ₁ ~
Since all selector 1002a _k becomes the same configuration, it will be described here only the comparison unit 1001a ₁ and selection unit 1002a _1.

[0165] In the radio communication apparatus shown in FIG. 15, the comparator unit 1001a _1, the reception level of the carrier # 1 output from the reception level detecting unit 111a _1, with a predetermined threshold value are compared, showing the comparison result The signal is sent to the selection unit 1002a ₁
Is output to

[0166] In selecting unit 1002a _1, in accordance with a signal indicating the comparison result, one of the transmission signal after transmission level control output from the null signal or division unit 104a ₁ is selected and output to IFFT section 105. That is,
Reception level output from the reception level detecting unit 111a ₁ null signal is selected when less than the predetermined threshold value, conversely, the reception level detecting unit 111a reception level is a predetermined threshold value outputted from the ₁ In the above case, the transmission signal after the transmission level control is selected. Here, the null signal is a signal whose transmission level is 0.

As described above, according to the present embodiment, the transmission level of a carrier whose reception level is greatly reduced is set to 0, and therefore, in a strong fading environment, the peak power can be reduced without lowering the transmission efficiency. Reduction can be achieved.

(Embodiment 12) In this embodiment, a case will be described in Embodiment 11 where the error rate characteristic and the peak power are adjusted according to the fluctuation of the channel quality.

The optimum value of the threshold value in the eleventh embodiment differs depending on the line quality. That is, even if the transmission level is lowered as the line quality becomes better, a desired error rate characteristic can be obtained on the communication partner side. Therefore, in this case, by setting the threshold value higher, the number of carriers whose transmission level becomes 0 is increased, and the peak power can be further reduced. Conversely, unless the transmission level is increased as the line quality deteriorates, it becomes difficult for the communication partner to obtain a desired error rate characteristic. Therefore, in this case, it is necessary to set a lower threshold value to reduce the number of carriers whose transmission level becomes zero. in this way,
The optimum threshold value depends on the line quality.

Therefore, in the present embodiment, the threshold of the reception level is changed according to the channel quality as follows. FIG. 16 is a block diagram illustrating a configuration of a wireless communication apparatus according to Embodiment 12 of the present invention. Note that FIG.
In FIG. 15, the same components as those in the eleventh embodiment (FIG. 15) are denoted by the same reference numerals as those in FIG. 15, and detailed description is omitted.

As shown in FIG. 16, the radio communication apparatus according to the present embodiment employs a configuration in which a selector 1003 is added to the radio communication apparatus according to the eleventh embodiment. In FIG. 16, selecting section 1003 compares a value indicating the line quality (for example, a ratio of desired wave to interference wave power) input as the line quality information with a predetermined threshold value indicating the line quality. . The comparison according to the result, either the threshold 1 or threshold 2 (threshold 1> threshold 2) is selected, the comparing unit 1001a ₁ ~ comparator unit 100
It is output to the 1a _k.

That is, when the value indicating the line quality is equal to or more than a predetermined threshold value (when the line quality is good), threshold value 1 is selected. If the value is less than the threshold value (when the line quality is poor), threshold value 2 is selected. That is, if the line quality is good, the threshold is set higher, and if the line quality is bad, the threshold is set lower.

As a result, selection units 1002a ₁ to 1
The number of null signals selected in 002a _k increases when the line quality is good, and decreases when the line quality is bad. Therefore, when the line quality is good, the reduction of the peak power is prioritized, and when the line quality is bad, the error rate characteristic is prioritized.

As described above, according to the present embodiment, the threshold of the reception level is adaptively changed according to the channel quality to change the number of carriers whose transmission level is 0, and thus the channel quality is reduced. , The error rate characteristic and the peak power can be adjusted in accordance with the variation of the peak power. That is, according to the present embodiment, even when the line quality varies in Embodiment 11, the peak power can be reduced while obtaining a desired error rate characteristic.

In the above description, two types of thresholds are used. However, the present invention is not limited to this, and three or more types of thresholds may be used. The same applies to the following embodiments.

(Embodiment 13) In this embodiment, a case will be described in Embodiment 11 where the transmission efficiency is increased when the time slot interval is long.

As described above, in the TDD system,
The longer the time slot interval, the greater the difference in transmission path characteristics between the receiving line and the transmitting line. Therefore, when the time slot interval is long, even if the reception level is greatly reduced, the line state changes at the time of transmission and becomes good,
The receiving level may not drop on the communication partner side. Therefore, in this case, the transmission efficiency may be increased by reducing the number of carriers whose transmission level is 0.

Therefore, in the present embodiment, the number of carriers whose transmission level is set to 0 is changed according to the length of the time slot interval as follows. FIG. 17 is a block diagram illustrating a configuration of a wireless communication apparatus according to Embodiment 13 of the present invention. Note that, in FIG.
The same components as those in FIG. 15 are denoted by the same reference numerals as those in FIG. 15, and detailed description is omitted.

As shown in FIG. 17, the wireless communication apparatus according to the present embodiment employs a configuration in which a selector 1004 is added to the wireless communication apparatus according to the eleventh embodiment. In FIG. 17, selection section 1004 compares a time slot interval, which is input from the upper layer as interval information, with a predetermined threshold value of the interval. Then, according to the comparison result, the threshold 1 or the threshold 2 (the threshold 1
> Threshold value 2) is selected, and the comparison unit 1
001a is output to the _1-comparison unit 1001a _k.

That is, if the time slot interval is equal to or greater than the predetermined threshold, threshold value 2 is selected. Conversely, if the time slot interval is less than the predetermined threshold value, threshold value 1 is selected. Is selected. That is, if the time slot interval is long, the threshold is set lower, and if the time slot interval is short, the threshold is set higher.

As a result, the selection units 1002a ₁ to 1001
The number of null signals to be selected at 002a _k is less if the time slot interval is long, conversely, increases if the time slot interval is short.

As described above, according to the present embodiment, the number of carriers whose transmission level is set to 0 is changed according to the length of the time slot interval. The transmission efficiency can be improved.

Note that Embodiments 1 to 17 can be implemented in appropriate combinations.

In Embodiments 1 to 17, OFDM
Although the modulation scheme has been described as an example of the multicarrier modulation scheme, the present invention can be implemented in any multicarrier modulation scheme.

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

[0186]

As described above, according to the present invention,
In wireless communication combining the multi-carrier modulation method and the CDMA method, the frequency use efficiency and the transmission efficiency are reduced even when the level of each carrier varies independently due to the effects of fading due to multipath. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a wireless communication device according to a first embodiment of the present invention.

FIG. 2A is a diagram illustrating a state of a reception level of each carrier of a multicarrier signal received by the wireless communication device according to the first embodiment of the present invention; FIG. 2B is a diagram illustrating wireless communication according to the first embodiment of the present invention; Diagram showing transmission level control performed by device

FIG. 3 is a diagram illustrating a state of a reception level of each carrier of a multicarrier signal received by a communication partner of the wireless communication apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a wireless communication device according to a second embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of a wireless communication device according to a third embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a wireless communication device according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the fourth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the fifth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a wireless communication apparatus according to a sixth embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the sixth embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the seventh embodiment of the present invention.

FIG. 12 is a block diagram illustrating a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the eighth embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the ninth embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a coefficient adjustment unit of the wireless communication apparatus according to the tenth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a wireless communication apparatus according to an eleventh embodiment of the present invention.

FIG. 16 is a block diagram showing a configuration of a wireless communication apparatus according to a twelfth embodiment of the present invention.

FIG. 17 is a block diagram showing a configuration of a wireless communication device according to a thirteenth embodiment of the present invention.

FIG. 18 is a block diagram showing a configuration of a conventional wireless communication device.

FIG. 19 is a diagram illustrating a state in which each chip of a code division multiplexed transmission signal is arranged on each carrier.

FIG. 20 is a diagram illustrating a state of a reception level of each carrier of a multicarrier signal received by a conventional wireless communication device.

[Explanation of symbols]

101a ₁ ~101a _n diffusion unit 102 adding unit 103 S / P section _{104a 1 ~104a k, 202a 1 ~202a} k divider 105 IFFT unit 106 radio transmission unit 107 antenna 108 radio reception unit 109 FFT unit 110a ₁ ~110a _k transmitted road compensator 111a ₁ ~111a _k received level detector 112 P / S unit 113a ₁ ~113a _n despreader 201,301a ₁ ~301a _k averaging unit _{401a 1 ~401a k, 402a 1 ~402a} k coefficient adjusting unit 501 , 601,701,801,803,901,1
001a ₁ ~1001a _k comparison unit 502,602,702,802,804,902,1
002a _{1 to} 1002a _k , 1003, 1004 Selection unit 805, 806 AND operation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 27/34 H04L 27/00 EF term (Reference) 5K004 AA08 JD02 5K022 AA04 AA10 AA43 DD01 DD13 DD19 DD23 DD33 EE01 EE22 EE32 FF01 5K035 AA06 BB02 CC01 CC08 DD01 EE04 FF01 5K067 AA02 AA11 CC02 CC04 CC10 EE02 EE10 GG08 GG09

Claims (20)

[Claims] 1. A radio communication apparatus used in a TDD communication system, comprising: spreading means for performing a spreading process on a plurality of transmission signals using different spreading codes; First multiplexing means for code division multiplexing, division means for dividing a signal after code division multiplexing for each chip, and generation of a multicarrier signal by frequency division multiplexing by allocating signals for each chip to different carriers and performing frequency division multiplexing Second multiplexing means, a level control means for performing transmission level control for each carrier so as to have a characteristic opposite to a level fluctuation applied to the multicarrier signal in a transmission line, and a transmission means for transmitting the multicarrier signal A wireless communication device comprising: 2. A receiving apparatus comprising: a receiving means for receiving a multicarrier signal transmitted from a communication partner via a receiving line; and a detecting means for detecting a reception level of each carrier of the multicarrier signal; 2. The wireless communication apparatus according to claim 1, wherein a level fluctuation applied to a transmission line is predicted from the reception level. 3. The level control unit according to claim 2, wherein the carrier level having a higher reception level detected by the detection unit has a lower transmission level, and the carrier level having a lower reception level has a higher transmission level. Wireless communication device. 4. A correction means for dividing the reception level of each carrier by the average value of the reception levels of all carriers to correct an error commonly included in the reception levels of the respective carriers, wherein the level control means comprises: 4. The wireless communication apparatus according to claim 3, wherein transmission level control is performed using the corrected reception level. 5. An apparatus according to claim 1, further comprising an averaging means for obtaining an average value of a reception level in a predetermined section for each carrier, wherein said level control means performs transmission level control using said average value. The wireless communication device according to claim 3 or 4. 6. The system according to claim 1, wherein the level control means sets the transmission level of each carrier to a predetermined upper limit or less.
The wireless communication device according to any one of claims 1 to 5. 7. The radio communication apparatus according to claim 6, wherein the level control means lowers the predetermined upper limit as the line quality becomes better. 8. The radio communication apparatus according to claim 6, wherein the level control means increases the predetermined upper limit as the interval between the time slots of the reception line and the transmission line increases. 9. The level control means according to claim 6, wherein the higher the signal quality of the channel, the higher the predetermined upper limit when transmitting the signal. Wireless communication device. 10. The wireless communication apparatus according to claim 6, wherein the level control means increases the predetermined upper limit as the number of code division multiplexes of the transmission signal increases. 11. The radio communication apparatus according to claim 1, wherein the level control means sets the transmission level of each carrier to be equal to or higher than a predetermined lower limit and equal to or lower than a predetermined upper limit. . 12. The level control means, when the reception level of each carrier detected by the detection means is lower than the average value of the reception levels of all carriers, performs the transmission level control using the average value. The wireless communication device according to any one of claims 3 to 11, wherein 13. The level control means, when the reception level detected by the detection means is lower than a predetermined threshold value, sets the transmission level of the carrier corresponding to the reception level to zero. The wireless communication device according to claim 3. 14. The radio communication apparatus according to claim 13, wherein the level control means sets the predetermined threshold value higher as the line quality becomes better. 15. The level control means according to claim 13, wherein the longer the interval between the time slots of the receiving line and the transmitting line, the lower the predetermined threshold value.
5. The wireless communication device according to 4. 16. A communication terminal device comprising the wireless communication device according to claim 1. Description: 17. A base station device comprising the wireless communication device according to claim 1. 18. A radio communication method used in a TDD communication system, wherein a level variation applied to a multi-carrier signal subjected to code division multiplexing and frequency division multiplexing on the multi-carrier signal in a transmission line is provided. A wireless communication method characterized by performing transmission level control having characteristics opposite to the above for each carrier. 19. A reception level of a multicarrier signal transmitted from a communication partner via a reception line is detected for each carrier, and a level variation applied on the transmission line is predicted from the reception level. 19. The wireless communication method according to 18. 20. The radio communication method according to claim 19, wherein the transmission level is set lower for a carrier having a higher reception level, and the transmission level is set higher for a carrier having a lower reception level.