JP3441922B2 - Signal transmission method and signal transmission device in CDMA mobile communication system - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to communication between a base station and a mobile station using a code division multiple access (CDMA) system, and a control signal on a radio channel established between the base station and the mobile station. Alternatively, the present invention relates to a signal transmission method and a signal transmission device for a mobile station or a base station in a CDMA mobile communication system that transmits a transmission signal including a user signal for communication.

[0002]

2. Description of the Related Art At present, in a digital mobile communication system (GSM) mainly provided in Europe, a radio channel set up before starting communication between a base station and a mobile station is taken as an example. A signal transmission method in the conventional mobile communication system will be described.

In GSM, a plurality of transmission signals are transmitted between a mobile station and a base station by a radio channel established between the mobile station and the base station before starting communication. The processing time of the transmission signal at the base station and the processing time of the mobile station reaches several hundred msec at the maximum, and the transmission signal is not transmitted on the radio channel during the processing time. However, in the conventional mobile communication system (GSM), the radio channel is constantly transmitted regardless of the presence / absence of a transmission signal to be transmitted.

In the CDMA mobile communication system, the system capacity is determined by the amount of interference power, and the system capacity decreases as the amount of interference power increases. In order to prevent an increase in the amount of interference power, it is necessary to prevent unnecessary radio channel transmission.

[0005]

Even in the conventional CDMA mobile communication system, when transmitting a transmission signal by a radio channel between a base station and a mobile station, the radio channel is irrespective of the presence or absence of the transmission signal to be transmitted. Was continuously transmitted, which would unnecessarily increase the amount of interference power.
There was a problem that the system capacity decreased.

The present invention has been made in view of the above,
An object of the present invention is to provide a signal transmission method in a CDMA mobile communication system and a signal transmission device for a mobile station or a base station, which prevent unnecessary increase in the amount of interference power due to signal transmission of a radio channel and prevent decrease in system capacity. To provide.

[0007]

In order to achieve the above object, a first feature of the present invention is that a base station and a mobile station communicate with each other using a code division multiple access (CDMA) system, In a signal transmission method in a CDMA mobile communication system that performs transmission by transmitting a transmission signal on a radio channel set with a mobile station, when there is no transmission signal including a control signal or a user signal to be transmitted on the radio channel, A signal part necessary for maintaining the radio channel is encoded and modulated to form the transmission signal, and a signal part not necessary for maintaining the radio channel including the transmission signal part is included in the transmission signal. The point is that there is no such thing.

The second feature of the present invention is the first feature of the present invention.
In the above, when there is a transmission signal to be transmitted on the wireless channel, the transmission signal is formed by combining the transmission signal and a signal necessary for maintaining the wireless channel, and the transmission signal to be transmitted on the wireless channel is When not present, the gist is to form the transmission signal with a signal necessary for maintaining the wireless channel.

The third feature of the present invention is the first or second aspect of the present invention.
The gist of the second feature is that signals necessary for maintaining the wireless channel are transmitted at the maximum transmission frequency.

A fourth aspect of the present invention is the first or the second aspect of the present invention.
In the second feature , the transmission frequency of a signal portion necessary for maintaining the wireless channel when there is no transmission signal to be transmitted on the wireless channel is the wireless channel when there is a transmission signal to be transmitted on the wireless channel. The gist is to reduce the frequency of transmission of the signal portion necessary for maintaining

The fifth feature of the present invention is the first or second aspect of the present invention.
In the second feature , when there is no transmission signal to be transmitted next after the immediately previous transmission signal transmission is completed on the wireless channel, the wireless channel is maintained immediately after the immediately previous transmission signal is completed. The gist is to gradually reduce the frequency of transmission of the required signal part.

A sixth feature of the present invention is the first or second aspect of the present invention.
In the second feature , when there is no transmission signal to be transmitted on the wireless channel, the transmission frequency of a signal portion necessary for maintaining the wireless channel is made smaller than the maximum transmission frequency, and a transmission signal to be transmitted is generated. Sometimes, it is a gist to transmit only the signal portion necessary for maintaining the wireless channel at the maximum transmission frequency for a predetermined period and then transmit the transmission signal.

The seventh feature of the present invention is the first or the first aspect of the present invention.
In the second feature , the transmission frequency of the signal portion required to maintain the wireless channel is changed according to the reception quality of the signal portion required to maintain the received wireless channel, and the reception quality is The gist of the invention is to increase the frequency of transmission of a signal portion necessary for maintaining the wireless channel as the deterioration deteriorates.

The eighth feature of the present invention is the seventh feature of the present invention.
The gist of the present invention is to use a desired wave reception level to interference wave reception level ratio (reception SIR) as the reception quality of a signal portion necessary for maintaining the received radio channel.

The ninth feature of the present invention is the seventh feature of the present invention.
In summary, the point is to use the bit error rate as the reception quality of the signal portion necessary for maintaining the received wireless channel.

The tenth feature of the present invention is the first or the second aspect of the present invention.
In the second feature , when the signal portion required to maintain the wireless channel cannot be received for a predetermined period or more, the transmission frequency of the signal portion required to maintain the wireless channel is maximized. Is the gist.

The eleventh feature of the present invention is the first feature of the present invention.
In any one of the eleventh to eleventh characteristics, either the base station or the mobile station determines a transmission frequency of a signal portion necessary for maintaining the radio channel transmitted from the local station, from the radio station from the other station. The gist is that the frequency is the same as the reception frequency of the signal portion necessary for maintaining the channel.

The twelfth feature of the present invention is the first feature of the present invention.
In any one of the eleventh to eleventh features, a signal portion necessary for maintaining the wireless channel is intermittently and periodically arranged in the wireless channel, and a signal necessary for maintaining the wireless channel. Is formed by thinning out the transmission signal, and the transmission signal is not transmitted in a portion corresponding to a signal necessary for maintaining the thinned wireless channel, and the wireless channel is maintained by changing the thinning number. The gist is to change the transmission frequency of the signal portion necessary for the operation.

The thirteenth feature of the present invention is the first feature of the present invention.
In any one of the twelfth to twelfth features, a pilot signal necessary for performing coherent detection reception, or transmission power control information necessary for performing transmission power control, in a signal portion required for maintaining the radio channel The gist is to include at least one of the above.

A fourteenth feature of the present invention is a signal transmission apparatus for performing communication by using a code division multiple access (CDMA) system, transmitting a transmission signal on a radio channel, and performing communication. Necessary signal generating means for generating a signal portion necessary for maintaining, transmission signal generating means for generating a transmission signal including a control signal or a user signal transmitted by the wireless channel, and the transmission signal transmitted by the wireless channel When there is not, the signal structure that configures the signal format so as to include a signal part necessary for maintaining the radio channel and not include a signal part that is unnecessary for maintaining the radio channel including the transmission signal part. Means, encoding means for encoding the signal format, modulation means for modulating the encoded signal format, and modulated means And summarized in that a means generating and transmitting the transmission signal based on the serial signal format.

The fifteenth feature of the present invention is the fourteenth feature of the present invention.
In the above feature , when there is a transmission signal to be transmitted on the wireless channel, the signal composing means configures the signal format by combining the transmission signal and a signal necessary to maintain the wireless channel, When there is no transmission signal to be transmitted on the channel, the gist is to configure the signal format with a signal necessary for maintaining the wireless channel.

The sixteenth feature of the present invention is the fourteenth feature of the present invention.
Alternatively, in the fifteenth feature , the necessary signal generating means is
The gist of the invention is to constantly generate a signal necessary for maintaining the wireless channel with the maximum transmission frequency.

The seventeenth feature of the present invention is the fourteenth feature of the present invention.
Alternatively, in the fifteenth feature , the signal composing means determines a transmission frequency of a signal portion necessary for maintaining the wireless channel when there is no transmission signal to be transmitted on the wireless channel,
The gist is that the signal format is configured to be smaller than the transmission frequency of the signal portion required to maintain the wireless channel when there is a transmission signal to be transmitted on the wireless channel.

The eighteenth feature of the present invention is the fourteenth feature of the present invention.
Alternatively, in the fifteenth feature , the signal constructing means, immediately after the immediately preceding transmission signal ends, when there is no transmission signal to be transmitted next after the immediately previous transmission signal transmission ends in the wireless channel, It is a gist to configure the signal format such that the transmission frequency of a signal portion necessary for maintaining the wireless channel is gradually reduced.

The nineteenth feature of the present invention is the fourteenth feature of the present invention.
Alternatively, in the fifteenth feature , the signal forming unit makes the transmission frequency of a signal portion necessary for maintaining the radio channel smaller than the maximum transmission frequency when there is no transmission signal to be transmitted on the radio channel, When a transmission signal to be transmitted is generated, the signal format is configured to transmit the transmission signal after transmitting only a signal portion necessary for maintaining the radio channel at the maximum transmission frequency for a predetermined period. Is the gist.

The twentieth feature of the present invention is the fourteenth feature of the present invention.
Alternatively, in the fifteenth feature , further comprising means for measuring the reception quality of a signal portion necessary for maintaining the received radio channel, wherein the signal configuration means determines the radio channel as the reception quality deteriorates. The gist is to configure the signal format so as to increase the transmission frequency of the signal portion necessary for maintaining.

The 21st feature of the present invention is the 20th feature of the present invention.
In the above feature , the means for measuring the reception quality of a signal portion necessary for maintaining the received radio channel is characterized by measuring a desired wave reception level to an interference wave reception level ratio (reception SIR).

The 22nd feature of the present invention is the 20th feature of the present invention.
In the above feature , the means for measuring the reception quality of the signal portion necessary for maintaining the received wireless channel is characterized in that the bit error rate is measured.

The 23rd feature of the present invention is the 14th feature of the present invention.
Alternatively, in the fifteenth feature , it further comprises means for detecting that a signal portion necessary for maintaining the radio channel has not been received for a predetermined period or longer, and the signal composing means comprises:
The signal format is configured to maximize the transmission frequency of the signal portion required to maintain the wireless channel when the signal portion required to maintain the wireless channel cannot be received for a predetermined period or longer. That is the summary.

The 24th feature of the present invention is the 14th feature of the present invention.
Alternatively, in any one of the twenty-third characteristics, there is further provided a means for measuring a reception frequency of a signal necessary for maintaining the received wireless channel, and the signal configuration means sets the wireless channel to be transmitted from the own station. The gist is to configure the signal format such that the transmission frequency of the signal portion necessary for maintaining is the same as the measured reception frequency.
The 25th feature of the present invention is the 14th or 24th feature of the present invention.
In any one of the features, the signal composing means intermittently and periodically arranges a signal portion necessary for maintaining the wireless channel in the wireless channel, and is necessary for maintaining the wireless channel. Signal is thinned to form the transmission signal, and the transmission signal is not transmitted in a portion corresponding to a signal necessary for maintaining the thinned radio channel, and the radio channel is changed by changing the thinning number. The gist is to configure the signal format so as to change the transmission frequency of the signal portion necessary for maintaining the above. The 26th feature of the present invention is the 14th or 2nd feature of the present invention.
In any one of the features of 5, the signal composing means is necessary for performing a coherent detection reception pilot signal or transmission power control on a signal portion required for maintaining the radio channel. The gist is to include at least one of the transmission power control information.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Further, in the following description, “a signal necessary for maintaining the wireless channel” is abbreviated as “necessary signal”.

FIG. 1 is a diagram showing the configuration of a signal transmission device for a mobile station or a base station for implementing the signal transmission method in the CDMA mobile communication system of the present invention. In realizing the signal transmission method of the present invention, the base station and the mobile station can use the signal transmission device having the same configuration shown in FIG.

The signal transmission apparatus shown in FIG. 1 generates a transmission signal transmitted by a radio channel from a required signal generator 10 for generating a required signal, a control signal from a controller 23 or a user signal from a user signal generator 27. Transmission signal generation unit 11, required signal generation unit 10, and transmission signal generation unit 11 that generate
A required signal and a transmission signal respectively, and a signal format configuration unit 12 that configures a signal format of a wireless channel according to the presence or absence of the transmission signal, and encodes the signal format configured by the signal format configuration unit 12, and performs encoding. A coding section 13 for generating a signal, a modulation section 14 for modulating and spreading the coded signal to generate a spread signal,
D / A conversion of spread signals, frequency conversion, etc.
A transmission unit 15 that generates a transmission signal with transmission ON / OFF and amplifies the transmission signal to a transmission power specified by the transmission power determination unit 25, a transmission / reception distribution unit 16 that divides the transmission signal and the reception signal, and transmission / reception It has an antenna 26 connected to the distributor 16.

Further, the signal transmission device of FIG. 1 further includes a receiving section 1 for performing amplification, frequency conversion, A / D conversion, etc. of the received signal.
7, a demodulation unit 18 that despreads and demodulates the reception signal from the reception unit 17 to generate a demodulation signal, a decoding unit 19 that decodes a transmission signal in the demodulation signal and sends the decoding signal to the control unit 23, a necessary signal from the demodulation signal Required signal extraction unit 20 for extracting the required signal, a reception frequency measurement unit 21 for measuring the reception frequency of the extracted required signal, a reception quality measurement unit 22 for measuring the reception quality of the required signal, and a control signal which is the source of the transmission signal. In addition, the control unit 23 that performs overall control, compares the reception quality of the required signal with a predetermined quality for transmission power control, and determines whether the reception quality is deteriorated or higher than the predetermined quality. It has a unit 24, a transmission power determination unit 25 that determines the transmission power according to the transmission power control information from the partner station included in the required signal, and a user signal generation unit 27 that generates the user signal.

The user signal generator 27 includes an interface with a microphone or an external terminal in a mobile station, and an interface with a wired transmission line from a higher station in a base station.

Next, a first embodiment of the signal transmission method of the present invention will be described. FIG. 2 is a diagram showing a correspondence example of a signal format and a transmission pattern of a transmission signal in this embodiment. The required signal generation unit 10 always generates the required signal at the maximum frequency and supplies it to the signal format configuration unit 12. The signal format configuration unit 12 is the transmission signal generation unit 1
When the transmission signal is supplied from 1, the signal format is configured by combining the transmission signal with the required signal of the maximum frequency supplied from the required signal generation unit 10 (period 30). When there is no transmission signal to be transmitted on the wireless channel and the transmission signal is not supplied from the transmission signal generation unit 11, the signal format is configured only by the maximum frequency required signal supplied from the required signal generation unit 10, and the transmission signal is transmitted. The portion for arranging is made empty (period 31).

The signal format formed by the signal format forming unit 12 is encoded, modulated and spread by the encoding unit 13 and the modulating unit 14, respectively, and the spread signal is supplied to the transmitting unit 15. The transmitter 15 performs D / A conversion, frequency conversion, amplification, etc. of the spread signal, and turns on transmission of a portion having a signal in the signal format, that is, a necessary signal portion and a transmission signal portion, and turns off an empty portion. The transmission pattern indicating the transmission ON / OFF timing in the transmission unit 15 is shown in FIG. 2 in association with the signal format.

In this embodiment, as shown in FIG. 2, when there is no transmission signal, transmission is turned off at the portion for arranging the transmission signal to prevent wasteful transmission of a radio channel and to prevent interference. It is possible to prevent a wasteful increase in the amount of electric power and prevent a decrease in system capacity. Further, since the necessary signal is always transmitted, the radio channel can be maintained between the mobile station and the base station even when there is no transmission signal to be transmitted, and the transmission quality can be kept good.

Next, a second embodiment of the signal transmission method of the present invention will be described. FIG. 3 is a diagram showing a correspondence example of a signal format and a transmission pattern of a transmission signal in this embodiment. In the present embodiment, the required signal generation unit 10 always generates the required signal at the maximum frequency and supplies it to the signal format configuration unit 12. When the transmission signal is supplied from the transmission signal generation unit 11, the signal format configuration unit 12 configures a signal format by combining the required signal of the maximum frequency supplied from the required signal generation unit 10 and the transmission signal (period. 40). There is no transmission signal to be transmitted on the wireless channel,
When the transmission signal is not supplied from the transmission signal generation unit 11, a predetermined number of necessary signals are thinned out from the required signals of the maximum frequency supplied from the required signal generation unit 10 to form a signal format with only the remaining required signals, The portion for arranging the transmission signal and the necessary signal portion thinned out are made empty (period 41). FIG. 3 shows a case where four of the five necessary signals are thinned out. The transmission pattern indicating the transmission ON / OFF timing in the transmission unit 15 is shown in FIG. 3 in association with the signal format.

In the present embodiment, as shown in FIG. 3, when there is no transmission signal, necessary signals are thinned out and the transmission frequency thereof is reduced, so that radio channels are transmitted more wastefully than in the case of FIG. It is possible to prevent the increase in the amount of interference power and prevent the decrease in system capacity. Here, it is meaningless to maintain the transmission quality of the radio channel in a good state during the period when there is no transmission signal. In that respect, the present embodiment can further reduce the amount of interference power by allowing the deterioration of the transmission quality when there is no transmission signal and reducing the transmission frequency of the required signal. Further, since the necessary signal is continuously transmitted, it is possible to prevent the wireless channel from being unable to be maintained due to loss of synchronization or the like on the receiving side.

Next, a third embodiment of the signal transmission method of the present invention will be described. FIG. 4 is a diagram showing a correspondence example of the signal format of the transmission signal and the transmission pattern in the present embodiment. In the present embodiment, the required signal generation unit 10 always generates the required signal at the maximum frequency and supplies it to the signal format configuration unit 12. When the transmission signal is supplied from the transmission signal generation unit 11, the signal format configuration unit 12 configures a signal format by combining the required signal of the maximum frequency supplied from the required signal generation unit 10 and the transmission signal (period. 50). After that, when there is no transmission signal to be transmitted on the wireless channel and the transmission signal is not supplied from the transmission signal generation unit 11, a predetermined number of required signals are thinned out from the maximum frequency required signals supplied from the required signal generation unit 10. The signal format is composed only of the remaining necessary signals, and the thinning-out number is increased with time immediately after the transmission of the immediately preceding transmission signal is completed. As a result, the transmission frequency of the necessary signal portion is gradually reduced immediately after the transmission of the immediately previous transmission signal is completed. The portion for arranging the transmission signal and the necessary signal portion thinned out are vacant and are not transmitted (period 51). Figure 4
Shows the case where the number of thinning-out required signals is gradually increased to 0 → 1 → 2 → 3 and the transmission frequency is gradually decreased. The transmission pattern indicating the transmission ON / OFF timing in the transmission unit 15 is shown in FIG. 4 in association with the signal format.

In the present embodiment, as shown in FIG. 4, when there is no transmission signal to be transmitted next after the transmission of the immediately previous transmission signal, the frequency of transmitting the necessary signal is set immediately after the transmission of the immediately previous transmission signal is completed. If the next transmission signal occurs after a short time has elapsed after the transmission of the transmission signal immediately before, the frequency of transmitting the necessary signal is not so small at that time, so the transmission quality of the wireless channel is Since the next transmission signal can be transmitted before it is deteriorated so much, the transmission success rate of the next transmission signal can be increased. Further, if the transmission signal does not occur for a long time after the transmission of the transmission signal immediately before, the amount of interference power can be further reduced by reducing the frequency of transmitting the necessary signal.

In the mobile communication system, when a plurality of transmission signals are transmitted, the subscriber memory in the network may or may not be accessed. When accessing, the subscriber memory is accessed for a long time. The time from transmitting one transmission signal to transmitting the next transmission signal also becomes long. When not accessed, multiple transmission signals are frequently transmitted. As described above, the time intervals for transmitting a plurality of transmission signals are the extremes of a short time and a long time, and according to the present invention, when the time interval for transmitting the transmission signals is short,
Since the influence of the transmission of the required signal on the interference power amount is small, it is possible to give priority to increasing the transmission success rate of the transmission signal generated next. Furthermore, if the transmission signal does not occur for a certain long time after the transmission signal immediately before,
Since the influence of the transmission of the necessary signal on the interference power amount is large, it is possible to give priority to further reducing the interference power amount by reducing the frequency of transmitting the necessary signal.

Next, a fourth embodiment of the signal transmission method of the present invention will be described. FIG. 5 is a diagram showing a correspondence example of the signal format of the transmission signal and the transmission pattern in the present embodiment. In the present embodiment, the required signal generation unit 10 always generates the required signal at the maximum frequency and supplies it to the signal format configuration unit 12. When the transmission signal is supplied from the transmission signal generation unit 11, the signal format construction unit 12
The required signal having the maximum frequency supplied from the required signal generator 10 and the transmission signal are combined to form a signal format (period 60). On the other hand, when there is no transmission signal to be transmitted on the wireless channel and the transmission signal is not supplied from the transmission signal generation unit 11, a predetermined number of required signals are thinned out from the maximum frequency required signals supplied from the required signal generation unit 10. The signal format is composed of only the necessary signals remaining. The portion for arranging the transmission signal and the thinned out necessary signal portion are vacant (period 61). When the transmission signal to be transmitted after that occurs again, only the necessary signal part with the maximum frequency
Configure a signal format for a predetermined time (period 62),
Next, the required signal of the maximum frequency and the transmission signal are combined to form a signal format (period 63). The transmission pattern indicating the transmission ON / OFF timing in the transmission unit 15 is shown in FIG. 5 in association with the signal format.

In the present embodiment, as shown in FIG. 5, by transmitting the required signal portion having the maximum frequency for a predetermined time before transmitting the transmission signal, the transmission quality can be improved before the transmission signal transmission. Therefore, the success rate of transmission signal transmission can be improved.

Next explained is the fifth embodiment of the signal transmission method of the invention. The reception quality measuring unit 22 measures the reception quality of the received required signal and notifies the control unit 23 of the measurement result. The measurement value notified to the control unit 23 is a measurement value of one required signal, an average value of reception qualities of a predetermined number of plural required signals, or an average reception quality of all required signals received within a predetermined period. The value. In the control unit 23, when the reception quality notified from the reception quality measuring unit 22 is deteriorated below a predetermined reception quality, or when a state in which the reception quality is deteriorated below a predetermined reception quality continues for a predetermined number of times, or when the reception quality is deteriorated below a predetermined reception quality. When the state continues for a predetermined time, the signal format composing unit 12 is instructed to maximize the transmission frequency of the required signal. In the signal format configuration unit 12, at the time of receiving the command, regardless of the presence or absence of the transmission signal to be transmitted at that time and the transmission frequency of the necessary signal,
Configure the signal format with the maximum frequency of required signals.

Further, in the control unit 23, the reception quality measuring unit 22
When the reception quality notified from is better than a predetermined reception quality, or when a predetermined number of good reception quality states are continuous, or when a good reception quality state is continuous for a predetermined time, Signal format configuration unit 1
2 is instructed to reduce the transmission frequency of the required signal below the maximum frequency. In the signal format construction unit 12,
At the time of receiving the command, if there is no transmission signal to be transmitted at that time, a predetermined number of required signals are thinned out from the required signals of the maximum frequency supplied from the required signal generation unit 10, and only the remaining required signals are used. Configure the signal format.

As the reception quality in this embodiment, the reception SIR or the bit error rate, which is the ratio of the desired wave reception level and the interference wave reception level, can be used.

FIG. 6 shows the correspondence between the reception quality variation of the required signal and the signal format and transmission pattern of the transmission signal. In FIG. 6, the reception SIR is used as the reception quality.
Further, when the reception SIR deteriorates below a predetermined value, the transmission frequency of the necessary signal is maximized, and when the reception SIR becomes better than the predetermined value, the necessary signal is transmitted at a frequency lower than the maximum frequency. There is. As a result, the required signal transmission frequency is lower than the maximum frequency during the period when the reception SIR is higher than the predetermined value (periods 70 and 72), and the required signal transmission frequency is lower than the predetermined value (period 71). Is the largest.

In FIG. 6, the predetermined value of the trigger for increasing the transmission frequency of the required signal (between the periods 70 and 71) and the predetermined value of the trigger for reducing the transmission frequency (between the periods 71 and 72). Although and have the same value, they may have different values.

Further, in FIG. 6 and the description thereof, one predetermined value is set and the required signal transmission frequency is set to two, but a plurality of predetermined values are set and the required signal transmission frequency is set to three or more. Fine control is also possible. At this time, the transmission frequency of the necessary signal portion is increased as the reception quality deteriorates.

FIG. 7 shows the correspondence between the fluctuation of the reception quality of the necessary signal, the signal format of the transmission signal, and the transmission pattern when three predetermined values and four transmission frequencies are used.
In FIG. 7, the predetermined values 1 to 3 are set in descending order of the reception SIR value (in order of good reception quality), and the reception SIR is less than or equal to the predetermined value 1 for a period (period 80) greater than the predetermined value 1 (predetermined value 1). Necessary signals with the maximum frequency for four types: a period greater than the value 2 (period 81), a period less than the predetermined value 2 and greater than the predetermined value 3 (period 82), and a period less than the predetermined value 3 (period 83). The case where the transmission frequency of the necessary signal is changed by setting the decimation numbers from to 3, 2, 1, 0 respectively.

When the radio channel in mobile communication has a high correlation of transmission quality between the upstream channel (mobile station → base station) and the downlink channel (base station → mobile station), and the reception quality is deteriorated at one station. Is likely to have deteriorated the reception quality of the other station. Therefore, in the present embodiment, when the reception quality of the required signal is deteriorated, it is highly possible that the reception quality of the partner station is deteriorated, and by increasing the frequency of transmission of the necessary signal, the radio signal transmitted from the own station is transmitted. It is possible to improve the transmission quality of the channel and improve the reception quality at the partner station. Conversely, if the reception quality of the required signal is good, it is highly possible that the reception quality of the partner station is also good, and it is possible to increase the amount of interference power unnecessarily by reducing the frequency of transmission of the necessary signal. It can prevent the decrease of system capacity.

Next explained is the sixth embodiment of the signal transmission method of the invention. The required signal extraction unit 20 extracts the received required signal and, when the required signal cannot be detected for a predetermined time or longer due to deterioration of reception quality, notifies the control unit 23 to that effect. Upon receiving this notification, the control unit 23 commands the signal format configuration unit 12 to maximize the frequency of transmission of the required signal. At the time of receiving the command, the signal format configuration unit 12 configures the signal format with the required signal of the maximum frequency regardless of the presence or absence of the transmission signal to be transmitted at that time and the transmission frequency of the required signal.

Further, after the required signal extracting section 20 cannot detect the required signal for a predetermined time or longer due to the improvement of the reception quality,
When the necessary signal is detected again for a predetermined time or longer, the control unit 23 is notified of that fact. When the control unit 23 receives this notification, it instructs the signal format configuration unit 12 to make the frequency of transmitting the necessary signal smaller than the maximum frequency. At the time of receiving the command, if there is no transmission signal to be transmitted at that time, the signal format construction unit 12 thins out the necessary signals so that the frequency is smaller than the maximum frequency designated by the control unit 23. Configure the signal format.

FIG. 8 shows the correspondence between the signal format of the transmission signal and the transmission pattern. The transmission frequency of the required signal is maximized in the period (period 91) from when it is determined that the required signal of the received signal is not detected to when it is determined that the required signal of the received signal is detected. Further, a period (period 90) until it is determined that the required signal of the received signal is not detected, and a period (period when it is determined that the required signal of the received signal is detected again after it is determined that the required signal of the received signal is not detected). In 92), the necessary signal is controlled to be transmitted at a frequency lower than the maximum frequency.

As described in the fifth embodiment, since the radio channel has a high correlation of the transmission quality between the upstream channel and the downstream channel, if the reception quality is deteriorated to the extent that the necessary signal cannot be detected, It is highly possible that the reception quality of the station has also deteriorated. Therefore, in the present embodiment, when the required signal cannot be detected, it is highly possible that the reception quality of the partner station has deteriorated, and by increasing the frequency of transmission of the required signal, transmission of the wireless channel transmitted from the own station is performed. The quality can be improved and the reception quality at the partner station can be improved. Conversely, if the required signal can be detected, that is, if the reception quality is good, then it is highly possible that the reception quality of the other station is also good, and the frequency of transmission of the necessary signal is reduced, resulting in unnecessary interference power. It is possible to prevent an increase in volume and prevent a decrease in system capacity.

Next explained is the seventh embodiment of the signal transmission method of the invention. The reception frequency of the necessary signal extracted by the necessary signal extracting unit 20 is measured at any time by the reception frequency measuring unit 21, and the measurement result is notified to the control unit 23 at any time. The control unit 23 notifies the signal format configuration unit 12 of the transmission frequency so that the transmission frequency of the necessary signal transmitted from the local station is the same as the measured reception frequency. When there is no transmission signal to be transmitted, the signal format composing unit 12 composes a signal format by thinning out necessary signals so as to realize the notified transmission frequency.

In the fifth and sixth embodiments described above, the transmission frequency of the required signal is changed depending on the reception quality of the required signal or detection / non-detection. However, this effect controls the reception quality of the partner station, and the reception quality of the own station was not improved. Therefore, by combining this embodiment, when the reception quality of the own station is poor, the transmission frequency of the necessary signal transmitted from the own station is increased, and the other station adjusts itself according to the frequency of the necessary signal received according to the present embodiment. Since the frequency of the required signal transmitted to the station is increased, the frequency of reception of the required signal of the own station is increased and the reception quality of the own station can be improved.

That is, by combining this embodiment with the above-described fifth and sixth embodiments, not only the reception quality of the partner station but also the reception quality of the own station can be improved. Further, like the transmission power control described later, it is not possible to improve the reception quality of the receiving side simply by increasing the transmission frequency of the required signal in one direction, but by increasing the transmission frequency in both directions, the reception quality of the receiving side can be increased. In some cases it can be raised. In such a case, the present embodiment is effective because the frequency of transmission of the required signal can be automatically increased in both directions.

Next, an eighth embodiment of the signal transmission method of the present invention will be described. The necessary signal generation unit 10 causes the necessary signal to include a pilot signal used for performing interpolated synchronous detection reception on the receiving side. Regarding the pilot signal and the interpolated synchronous detection receiving method, PCT application international publication number WO9
Details are described in 5/35615. Interpolation synchronous detection reception inserts a known pilot signal into the wireless channel at a predetermined frequency, and the receiving side estimates the propagation function in the wireless section by receiving the known pilot signal, and the transmission sandwiched between two pilot signals. This is a method of performing synchronous detection on a signal based on the estimated propagation function. When there is no transmission signal to be transmitted, it is not necessary to estimate the propagation function, so transmitting pilot signals with a high transmission frequency unnecessarily increases the amount of interference power. When there is no transmission signal to be transmitted, the amount of interference power can be reduced by reducing the transmission frequency of pilot signals.

Next, a ninth embodiment of the signal transmission method of the present invention will be described. The necessary signal generation unit 10 causes the necessary signal to include synchronization information necessary for holding reception synchronization on the receiving side. In order for the receiving side to receive the wireless channel, it must be synchronized with the wireless channel. Since the synchronization timing changes as the mobile station moves, the receiving side needs to follow the synchronization timing. In order to follow the synchronization timing, synchronization information with a known bit pattern is needed in the radio channel. If the frequency of transmitting the synchronization information is increased, stable reception synchronization can be achieved on the receiving side. On the other hand, if the frequency of transmitting the synchronization information is low, the reception side is likely to lose synchronization, and the reception quality of the wireless channel deteriorates. However, considering the aspect of increasing the amount of interference power by frequently transmitting synchronization information, it is necessary to allow deterioration of reception quality and reduce the frequency of transmission of necessary information when there is no transmission signal to be transmitted. .
At this point, the present embodiment that reduces the frequency of transmitting the synchronization information when there is no transmission signal to be transmitted is effective.

Next, a tenth embodiment of the signal transmission method of the present invention will be described. The required signal generation unit 10 causes the required signal to include a sequence number required for sequence control during transmission or reception. As an example in which order control is required, there is a combination in soft handover specific to the CDMA mobile communication system. At the time of soft handover, the mobile station communicates via a plurality of base stations. Taking the uplink direction as an example, a radio channel transmitted from one mobile station is received by a plurality of base stations, and a higher-order station of the base station synthesizes the received signals of the plurality of base stations to obtain a high-quality received signal. To generate. In this combination, it is not guaranteed that a plurality of received signals from a plurality of base stations will arrive at an upper station at the same time, so it is necessary to control the order so that the correspondence of the received signals to be combined among the plurality of received signals can be known. . Therefore, the mobile station transmits a radio frame to which a sequence number is added, and the upper station synthesizes a plurality of frames having the same sequence number in a plurality of received signals received by a plurality of base stations. As a result, highly reliable composition processing can be performed.

Since the sequence control may be performed only when there is a transmission signal to be transmitted, the sequence control is unnecessary when there is no transmission signal. Therefore, if there is no transmission signal, by reducing the transmission frequency of sequence numbers necessary for sequence control,
It is possible to avoid unnecessarily increasing the amount of interference power.

Next, an eleventh embodiment of the signal transmission method of the present invention will be described. The required signal generation unit 10 includes the required power in the required power control information for performing the transmission power control. For the transmission power control method, see Table 4-5.
Details are described in No. 02841. The comparison unit 24 compares the reception quality of the required signal measured by the reception quality measurement unit 22 with a predetermined quality, and informs the required signal generation unit 10 whether the reception quality is deteriorated or higher than the predetermined quality. Notice. The required signal generation unit 10 sets the transmission power control information included in the required signal to a bit that means “increase the transmission power by a predetermined value” when the reception quality is degraded from the predetermined quality, and the reception quality is When the quality is higher than the predetermined quality, the transmission power control information included in the necessary signal is a bit that means “reduce the transmission power by a predetermined value”.

The transmission power determination unit 25 of the partner station receives the required signal from the required signal extraction unit 20, and the transmission power control information included in the required signal is a bit that means "increase the transmission power by a predetermined value". In some cases, the transmission power is determined to be a value increased from the current value by a predetermined value, and if it is a bit that means “reduce the transmission power by a predetermined value”, the transmission power is decreased from the current value by a predetermined value. The determined transmission power value is notified to the transmission unit 15.
The transmission unit 15 performs amplification so as to realize the notified transmission power value and generates a transmission signal.

By the above operation, the transmission power can be controlled so that the reception quality follows the predetermined quality, and the unnecessary transmission power can be reduced and the interference power amount can be suppressed while satisfying the predetermined quality. it can. The more frequently the reception quality and the predetermined quality are compared and the transmission power control information is transmitted, the smaller the error in the reception quality with respect to the predetermined quality becomes.
It is possible to prevent the deterioration of quality or the increase of useless interference power.

When there is no transmission signal to be transmitted, even if the error of the reception quality with respect to the predetermined quality is large, there is little influence on the deterioration of the quality or the increase of the interference power amount. Therefore, when there is no transmission signal, the frequency of transmission of the transmission power control information is reduced to avoid unnecessary increase of the amount of interference power.

The signal transmission method of the present invention described above is effective for transmission signals transmitted intermittently. Since the control signal is not transmitted while the mobile station or the base station is processing the control signal, the control signal is intermittently transmitted. Therefore, the present invention is effective for the transmission of the control signal. Furthermore, the present invention is effective because user signals to which packet transmission is applied are also intermittently transmitted. As an example,
One example is the transmission of user information by IP packets on the Internet, which has been rapidly spreading in recent years. Since the IP bucket is transmitted only when the user performs some operation on the terminal, it becomes an intermittent transmission. Not only IP packets but also X. Similarly, the transmission of user information using another packet protocol such as 25 can be intermittent transmission, so the present invention is effective over packet transmission in general.

[0070]

As described above, according to the present invention, when there is no transmission signal to be transmitted on the radio channel, only the signal portion necessary for maintaining the radio channel is transmitted and the radio signal including the transmission signal portion is transmitted. By not transmitting the signal part that is not necessary for maintaining the channel, it is possible to prevent the wireless channel from being wastefully transmitted, prevent the wasteful increase in the amount of interference power, and prevent the system capacity from decreasing. .
Further, since the necessary signal is always transmitted, the radio channel can be maintained between the mobile station and the base station even during the period when there is no transmission signal to be transmitted.

Further, according to the present invention, when there is no transmission signal, the transmission frequency of the necessary signal portion is reduced to prevent the radio channel from being transmitted more wastefully and increase the amount of interference power wastefully. It is possible to prevent the system capacity from decreasing. Here, if there is no transmission signal, it is meaningless to maintain the transmission quality of the wireless channel in a good state. In this respect, the present invention can further reduce the amount of interference power by allowing the deterioration of the transmission quality when there is no transmission signal and reducing the transmission frequency of the required signal. Further, since the necessary signal is continuously transmitted, it is possible to prevent the wireless channel from being unable to be maintained due to loss of synchronization or the like on the receiving side.

Further, according to the present invention, when there is no transmission signal to be transmitted next after the transmission of the transmission signal immediately before, the frequency of transmitting the necessary signal immediately after the transmission of the transmission signal immediately before is reduced with time. Therefore, if the next transmission signal occurs after some time has passed after the transmission signal immediately before,
At that time, the frequency of transmitting the necessary signals has not decreased so much, so the next transmission signal can be transmitted before the transmission quality of the wireless channel is significantly degraded, so the transmission success rate of the next transmission signal should be increased. You can Further, if the transmission signal does not occur for a long time after the transmission of the transmission signal immediately before, the amount of interference power can be further reduced by reducing the frequency of transmitting the necessary signal. In mobile communication systems, when performing multiple transmission signal transmissions,
The subscriber memory in the network may or may not be accessed. When accessing the subscriber memory, it takes a long time to access the subscriber memory, so one transmission signal is transmitted until the next transmission signal is transmitted. It takes longer time.
When not accessed, multiple transmission signals are frequently transmitted. As described above, the time intervals for transmitting a plurality of transmission signals are the extremes of the case of being short and the cases of being long, and according to the present invention, when the time interval for transmitting the transmission signals is short, the transmission of the necessary signal gives the interference power amount. Since the influence is small, it is possible to give priority to increasing the transmission success rate of the transmission signal generated next. Furthermore, if the transmission signal does not occur for a certain long time after the transmission of the transmission signal immediately before, the transmission of the required signal has a large effect on the amount of interference power. Reducing the amount can be a priority.

Further, according to the present invention, by transmitting only the required signal portion of maximum frequency for a predetermined time before transmitting the transmission signal, the transmission quality can be improved before the transmission signal transmission. The success rate of signal transmission can be improved.

Further, according to the present invention, when the reception quality of the required signal is deteriorated, it is highly possible that the reception quality of the partner station is deteriorated. Therefore, by increasing the transmission frequency of the necessary signal, It is possible to improve the transmission quality of the radio channel transmitted from the station and improve the reception quality at the partner station. Conversely, if the reception quality of the required signal is good, it is highly possible that the reception quality of the partner station is also good, and it is possible to increase the amount of interference power unnecessarily by reducing the frequency of transmission of the necessary signal. It can prevent the decrease of system capacity.

Further, according to the present invention, since the radio channel has a high correlation between the transmission quality of the upstream channel and the transmission quality of the downlink channel, when the reception quality is deteriorated to the extent that the necessary signal cannot be detected, the reception quality of the partner station is also reduced. It is likely that it has deteriorated. Therefore, if the required signal cannot be detected, it is highly possible that the reception quality of the other station has deteriorated, and the transmission frequency of the required signal is increased to improve the transmission quality of the wireless channel transmitted from the own station. Thus, the reception quality at the partner station can be improved. Conversely, if the required signal can be detected, that is, if the reception quality is good, then it is highly possible that the reception quality of the other station is also good, and the frequency of transmission of the necessary signal is reduced, resulting in unnecessary interference power. It is possible to prevent an increase in volume and prevent a decrease in system capacity.

Furthermore, according to the present invention, the frequency of signal transmission necessary for maintaining the radio channel transmitted from the local station is
By making the frequency of reception of the signal necessary for maintaining the wireless channel from the partner station the same, if the reception quality of the local station is poor, increase the frequency of transmission of the necessary signal from the local station Since the frequency of the necessary signal transmitted to the local station is increased according to the frequency of the required signal received by the local station, the frequency of receiving the necessary signal of the local station is increased and the reception quality of the local station can be improved.

Further, according to the present invention, the propagation function is estimated when there is no transmission signal to be transmitted by including the pilot signal used for performing the interleaved synchronous detection reception on the reception side in the required signal. Since it is not necessary to transmit the pilot signal with a high transmission frequency, the amount of interference power is unnecessarily increased. Therefore, when there is no transmission signal to be transmitted, the transmission frequency of the pilot signal can be reduced. The amount of interference power can be reduced.

Further, according to the present invention, by including the synchronization information required for maintaining the reception synchronization on the receiving side in the required signal, deterioration of the reception quality is allowed when there is no transmission signal to be transmitted. The amount of interference power can be reduced by reducing the frequency of transmission of necessary information.

Further, according to the present invention, the required signal includes a sequence number required for sequence control at the time of transmission or reception. Since the sequence control only needs to be performed when there is a transmission signal to be transmitted, the sequence control is not necessary when there is no transmission signal. Therefore, when there is no transmission signal, the transmission frequency of the sequence number required for sequence control. It is possible to avoid unnecessarily increasing the amount of interference power by reducing.

Further, according to the present invention, the necessary signal includes the transmission power control information necessary for controlling the transmission power.
As a result, when there is no transmission signal to be transmitted, even if there is a large error in the reception quality with respect to the predetermined quality, there is little effect on the deterioration of quality or the increase in the amount of interference power. By reducing the transmission frequency of the transmission power control information, it is possible to avoid unnecessarily increasing the amount of interference power.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a mobile station or base station signal transmission apparatus that implements a signal transmission method in a CDMA mobile communication system of the present invention.

FIG. 2 is a diagram showing a correspondence example of a signal format of a transmission signal and a transmission pattern in the first embodiment of the present invention.

FIG. 3 is a diagram showing a correspondence example of a signal format of a transmission signal and a transmission pattern in the second embodiment of the present invention.

FIG. 4 is a diagram showing a correspondence example of a signal format of a transmission signal and a transmission pattern in the third embodiment of the present invention.

FIG. 5 is a diagram showing an example of correspondence between a signal format of a transmission signal and a transmission pattern in the fourth embodiment of the present invention.

FIG. 6 is a diagram showing a correspondence example of a reception SIR of a signal necessary for maintaining a wireless channel and a signal format of a transmission signal and a transmission pattern in the fifth embodiment of the present invention.

FIG. 7 is a diagram showing another correspondence example of a reception SIR of a signal necessary for maintaining a wireless channel and a signal format of a transmission signal and a transmission pattern in the fifth embodiment of the present invention.

FIG. 8 is a diagram showing an example of correspondence between a signal format of a transmission signal and a transmission pattern in the sixth embodiment of the present invention.

[Explanation of symbols]

10 Required signal generator 11 Transmission signal generator 12 Signal format component 13 Encoding section 14 Modulator 15 Transmitter 16 Transmission / reception distribution unit 17 Receiver 18 Demodulator 19 Decoding section 20 Required signal extractor 21 Reception frequency measurement unit 22 Reception quality measurement unit 23 Control unit 24 Comparison section 25 Transmit power determination unit 26 antenna 27 User signal generator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-312783 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 7/24-7/26 H04Q 7 / 00-7/38

Claims (24)

(57) [Claims] 1. A base station and a mobile station communicate with each other using a code division multiple access (CDMA) method, and transmit a transmission signal through a radio channel set between the base station and the mobile station to perform communication. In the signal transmission method in a CDMA mobile communication system, the synchronous detection reception is performed when there is no transmission signal including a control signal or a user signal transmitted on the radio channel.
To control the pilot signal or transmission power required for
A signal not necessary for maintaining the wireless channel including at least one of the transmission power control information and forming the transmission signal only by a signal part necessary for maintaining the wireless channel including the transmission signal part. A signal transmission method in a CDMA mobile communication system, wherein a part is not included in the transmission signal. 2. When there is a transmission signal to be transmitted on the wireless channel, the transmission signal is combined with a signal necessary for maintaining the wireless channel to form the transmission signal, and the transmission is transmitted on the wireless channel. When there is no signal,
The signal transmission method according to claim 1, wherein the transmission signal is formed by a signal necessary for maintaining the wireless channel. 3. The signal transmission method according to claim 1, wherein a signal necessary for maintaining the radio channel is transmitted at a maximum transmission frequency. 4. The transmission frequency of a signal portion necessary for maintaining the wireless channel when there is no transmission signal to be transmitted on the wireless channel, the wireless channel when there is a transmission signal to be transmitted on the wireless channel, The signal transmission method according to claim 1 or 2, wherein the transmission frequency of the signal portion required to maintain the signal transmission frequency is reduced. 5. If there is no transmission signal to be transmitted next after the transmission signal transmission immediately before on the radio channel is completed,
3. The signal transmission method according to claim 1, wherein the frequency of transmission of a signal portion necessary for maintaining the radio channel is gradually reduced immediately after the immediately preceding transmission signal is completed. 6. When there is no transmission signal to be transmitted on the radio channel, the frequency of transmission of a signal portion necessary for maintaining the radio channel is set smaller than the maximum transmission frequency,
2. When a transmission signal to be transmitted is generated, only the signal portion necessary for maintaining the radio channel is transmitted at the maximum transmission frequency for a predetermined period, and then the transmission signal is transmitted. 2. The signal transmission method described in 2. 7. The reception quality is deteriorated by changing the transmission frequency of the signal portion required for maintaining the wireless channel according to the reception quality of the signal portion required for maintaining the received wireless channel. The signal transmission method according to claim 1 or 2, wherein the frequency of transmission of a signal portion necessary for maintaining the wireless channel is increased as the transmission is performed. 8. The signal according to claim 7, wherein a desired wave reception level-to-interference wave reception level ratio (reception SIR) is used as the reception quality of a signal portion required to maintain the received radio channel. Transmission method. 9. The signal transmission method according to claim 7, wherein a bit error rate is used as a reception quality of a signal portion necessary for maintaining the received radio channel. 10. The transmission frequency of the signal portion required to maintain the wireless channel is maximized when the signal portion required to maintain the wireless channel cannot be received for a predetermined period or longer. The signal transmission method according to claim 1 or 2. 11. One of the base station and the mobile station determines the transmission frequency of a signal portion necessary for maintaining the wireless channel transmitted from the local station, and the maintenance of the wireless channel from the other station. The signal transmission method according to any one of claims 1 to 10, characterized in that the frequency is the same as the reception frequency of the signal portion required in (1). 12. The transmission is performed by intermittently and periodically arranging a signal portion necessary for maintaining the wireless channel, and thinning out a signal necessary for maintaining the wireless channel. It is assumed that the transmission signal is not transmitted in a portion corresponding to a signal necessary for forming a signal and maintaining the thinned wireless channel, and is necessary for maintaining the wireless channel by changing the thinning number. 12. The signal transmission method according to claim 1, wherein the transmission frequency of the signal portion is changed. 13. A signal transmission device that performs communication using a code division multiple access (CDMA) system and transmits a transmission signal on a wireless channel to perform communication, the signal being necessary for maintaining the wireless channel. A necessary signal generating means for generating a portion, a transmission signal generating means for generating a transmission signal including a control signal or a user signal to be transmitted on the wireless channel, and a synchronous detection reception when there is no transmission signal to be transmitted on the wireless channel. Pilot signal or
Is a small amount of transmission power control information required for transmission power control.
A signal format is configured so as to include only a signal portion necessary for maintaining the wireless channel including at least one and not include a signal portion unnecessary for maintaining the wireless channel including a transmission signal portion. A signal transmission device comprising: a signal forming unit; a modulating unit that modulates the signal format; and a unit that generates and transmits the transmission signal based on the modulated signal format. 14. The signal composing means composes the signal format by combining the transmission signal and a signal necessary for maintaining the radio channel when there is a transmission signal to be transmitted on the radio channel. When there is no transmission signal to transmit on the wireless channel,
14. The signal transmission device according to claim 13 , wherein the signal format is configured by a signal necessary for maintaining the wireless channel. 15. The required signal generating means, the signal transmission apparatus according to required signal for maintaining the radio channel, in claim 13 or 14, characterized in that to produce a maximum transmission frequency at all times. 16. The signal composing means has a transmission signal for transmitting on the wireless channel, the transmission frequency of a signal portion necessary for maintaining the wireless channel when there is no transmission signal for transmitting on the wireless channel. 15. The signal transmission device according to claim 13 or 14 , wherein the signal format is configured to be smaller than a transmission frequency of a signal portion required to maintain the radio channel at that time. 17. The signal constructing means, when there is no transmission signal to be transmitted next after the transmission signal transmission immediately before on the radio channel is completed, immediately after the transmission signal immediately before is completed, claim, characterized in that each of the signal format so as to gradually reduce the transmission frequency of the necessary signal portions in maintaining the channels 13 or
14. The signal transmission device according to 14 . 18. The signal forming means, when there is no transmission signal to be transmitted on the wireless channel, reduces the transmission frequency of a signal portion necessary for maintaining the wireless channel to a frequency lower than the maximum transmission frequency, and transmits the signal. When the transmission signal is generated, the signal format is configured to transmit the transmission signal after transmitting only the signal portion necessary for maintaining the wireless channel at the maximum transmission frequency for a predetermined period. The signal transmission device according to claim 13 or 14 . 19. The apparatus further comprises means for measuring a reception quality of a signal portion necessary for maintaining the received radio channel, wherein the signal configuration means maintains the radio channel as the reception quality deteriorates. The signal transmission device according to claim 13 or 14 , wherein the signal format is configured so as to increase the frequency of transmission of the signal portion required above. 20. The means for measuring the reception quality of a signal portion necessary for maintaining the received radio channel is characterized by measuring a desired wave reception level to an interference wave reception level ratio (reception SIR). The signal transmission device according to claim 19 . 21. The signal transmission device according to claim 19 , wherein the means for measuring the reception quality of the signal portion necessary for maintaining the received radio channel measures a bit error rate. 22. The apparatus further comprises means for detecting that a signal portion necessary for maintaining the wireless channel has not been received for a predetermined period or longer, and the signal forming means is necessary for maintaining the wireless channel. If the a signal portion can not be received over a predetermined time period, according to claim 13, characterized in that each of the signal format to maximize the transmission frequency of the necessary signal portions in maintaining the radio channel or 14. The signal transmission device according to 14 . 23. Further comprising means for measuring a reception frequency of a signal necessary for maintaining the received wireless channel, wherein the signal composing means is necessary for maintaining the wireless channel transmitted from the own station. 7. The signal format is configured such that the transmission frequency of a different signal portion is the same as the measured reception frequency.
23. The signal transmission device according to any one of 13 to 22 . 24. The signal composing means intermittently and periodically arranges a signal portion necessary for maintaining the wireless channel, and is necessary for maintaining the wireless channel. The transmission signal is formed by thinning out the signal, and the transmission signal is not transmitted in a portion corresponding to a signal necessary for maintaining the thinned radio channel, and the radio channel is changed by changing the thinning number. 13 through claim, characterized in that each of the signal format to change the transmission frequency of the necessary signal portions in maintaining
23. The signal transmission device according to any one of 23 .