JPH08237735A - Mobile communication system and radio communication equipment used for the system and radio data transmission method - Google Patents

Abstract

PURPOSE: To minimize the reduction in the transmission efficiency due to re- transmission and to improve the transmission efficiency in the state of not requiring re-transmission. CONSTITUTION: When it is discriminated that re-transmission of data to mobile stations MS1-MSm is required by base stations BS1-BSn, a channel operating state discrimination means 21 discriminates the operating state of all radio channels. When dead channels more than the number of channels required for re-transmission are available, the dead channels are used and a request of re- transmission of data by using the dead channels is reported to the mobile stations, and although dead channels are available but the number of the channels is less than the required number of channels for re-transmission, a request of re-transmission of data by using the dead channels and radio channels in use by a concerned mobile station is reported to the mobile stations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital mobile communication system adopting a TDMA system or a CDMA system as a connection system such as a digital automobile / mobile phone system or a digital cordless phone system, and more particularly to a data transmission procedure. The present invention relates to a system having a retransmission procedure, a wireless communication device used in this system, and a wireless data transmission method.

[0002]

2. Description of the Related Art In recent years, various developments and practical applications of digital mobile communication systems such as digital automobiles and mobile phone systems have been made, and among them, there are systems provided with a retransmission procedure as a data transmission procedure.

There are the following two types of conventional data retransmission methods in this type of system. That is, first of all, the first method is to set a plurality of radio channels fixedly as channels for each mobile station to perform data transmission and retransmission, and when retransmission is required during data transmission, This is a method in which the data transmission is temporarily suspended and retransmitted using the channel on which the data transmission was performed. On the other hand, in the second method, a plurality of wireless channels are fixedly divided and set in advance into a transmission channel and a retransmission dedicated channel, and if retransmission is necessary during data transmission, the data transmission is not changed. This is a method of continuously retransmitting using the dedicated channel for retransmission.

[0004]

However, each of these methods has the following problems to be solved.
That is, in the first method, the retransmission data is resent using the channel currently used for transmission as it is. Therefore, when there is untransmitted transmission data, the transmission of this untransmitted transmission data is temporarily suspended until the above-mentioned retransmission is completed, and as a result, the average transmission speed becomes slower and the transmission efficiency is reduced. Cause decline.

On the other hand, in the second method, when it becomes necessary to retransmit, the retransmission is performed using the dedicated channel for retransmission.
When there is untransmitted transmission data, it is not necessary to interrupt the transmission of this data, and therefore, it is possible to perform the transmission more efficiently than the first method. However, if the transmission quality is relatively low and the transmission quality is relatively low, the channel set for dedicated retransmission will not be used at all. Therefore, when it is desired to improve the transmission efficiency as much as possible when the communication traffic becomes high, the demand cannot be met.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress the decrease in transmission efficiency due to retransmission as much as possible and to improve the transmission efficiency in a state where retransmission is not required. (EN) Provided are a mobile communication system, a wireless communication device used in this system, and a wireless data transmission method.

[0007]

In order to achieve the above object, the mobile communication system of the present invention comprises a channel use state determining means and a channel allocation control means. Then, when executing the retransmission procedure, the channel use state determining means determines whether or not there are a plurality of empty wireless channels necessary for executing the retransmission procedure among the plurality of wireless channels, and the retransmission procedure is performed. When it is determined that there are as many free wireless channels as necessary to execute the above, the free wireless channels are allocated by the channel allocation control means for the retransmission procedure.

The channel assignment control means assigns a fixed wireless channel to the mobile station among a plurality of wireless channels when starting wireless data transmission, and retransmits the wireless channel during the wireless data transmission. When executing the procedure, an empty radio channel is selected from the radio channels fixedly assigned to other mobile stations and assigned to the mobile station based on the determination result of the channel use state determination means. It is characterized by that.

Further, in the mobile communication system of the present invention, when the channel use status determining means determines that there are no empty radio channels necessary for executing the retransmission procedure, the channel allocation control means It is also characterized in that the transmission by the radio channel being used for radio data transmission is temporarily suspended, and then a necessary number of radio channels including the used radio channel and an empty radio channel are allocated for the retransmission procedure. .

On the other hand, the radio communication apparatus of the present invention used as a base station is provided with a channel use state judging means and a retransmission request sending means, and when executing the retransmission procedure, a plurality of channels are used by the channel use state judging means. It is determined whether or not there are as many free wireless channels as necessary to execute the above retransmission procedure in the wireless channels of, and it is determined that there are as many free wireless channels as necessary to perform the retransmission procedure. In this case, the resending request sending means sends a request for resending using the vacant radio channel to the corresponding mobile station.

Further, the radio communication device used as a mobile station is provided with a channel use state determining means and a retransmission request sending means, and when executing the retransmission procedure, the channel use state determining means causes a plurality of radio channels to be transmitted. If it is determined that there are as many free wireless channels as necessary to execute the above retransmission procedure, and if it is determined that there are as many free wireless channels as necessary to perform the retransmission procedure. In the above, the resending request sending means sends a request to the base station for resending using the empty radio channel.

Further, in the wireless data transmission method of the present invention, when executing the retransmission procedure, it is determined whether or not there are a number of empty wireless channels necessary for executing the retransmission procedure among the plurality of wireless channels. And a step of allocating the vacant radio channel for the retransmission procedure when it is determined by this step that there are the number of vacant radio channels necessary for executing the retransmission procedure. It is a thing.

[0013]

As a result, according to the mobile communication system, the wireless communication device and the wireless data transmission method of the present invention, when retransmission is required during data transmission, the presence or absence of a vacant wireless channel is judged at that time, and the vacant wireless channel is determined. If there is a wireless channel of, this free channel is assigned for retransmission. For this reason, it is possible to continue data transmission on the wireless channel assigned to the own station during transmission and to retransmit data on an idle channel in parallel with the data transmission. Therefore, since it is not necessary to interrupt the original data transmission, the transmission efficiency can be increased accordingly.

Further, since the empty channel is used only when the need for retransmission occurs, it is possible to allocate all of the above empty channels to each mobile station as channels for data transmission in a state where there is no need for retransmission. It will be possible. Therefore, it is possible to improve the data transmission efficiency in a state where the wireless transmission quality is good, and thereby it is possible to provide a system having a high accommodation capacity.

Further, according to the system of the present invention, in the system which employs a so-called pre-assignment system in which a fixed wireless channel is fixedly assigned to the mobile station at the start of data transmission, the above-mentioned pre-assignment method is used when performing retransmission. If the wireless channel assigned to another mobile station is free, then this free channel will be assigned for retransmission of the mobile station without paying attention to the assignment. That is, it is possible to dynamically allocate and use radio channels despite the system of the pre-assign system, which can improve the transmission efficiency when retransmission is required.

Further, when there are not enough free wireless channels to execute the retransmission procedure, the transmission by the wireless channel in use is temporarily suspended, and then the unused wireless channel and the free wireless channel are used. The required number of radio channels, including radio channels, are allocated for the retransmission procedure. Therefore, it is possible to reliably perform retransmission even when there is no free channel.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a digital mobile communication system according to an embodiment of the present invention.

This system comprises a control station CS, a plurality of base stations BS1, BS2, ... And a plurality of mobile stations MS1, MS.
2, ... and are provided. The control station CS is connected to the wired public network NW via the wired line CL. The base stations BS1, BS2, ...
It is connected to the control station CS via 2, ... The base stations BS1, BS2, ... Form radio zones E1, E2 ,. Base station BS
1, BS2, ... Are assigned radio frequencies so that radio frequencies are different at least between adjacent radio zones.

By the way, the base stations BS1, BS2, ...
Time-division multiple access / time-division bidirectional (TDMA-TD) using mobile stations existing in their own radio zones E1, E2, ...
Wireless communication is performed by the D) method.

For example, four mobile stations MS are provided in the base station BS1.
1 to MS4 are connected, a radio frequency f1 is assigned between these base station BS1 and each mobile station MS1 to MS4. As shown in FIG. 2, the transmission format divides one frame into a forward link period and a reverse link period, and further divides these periods into four slots T1 to T4 and R1.
To R4. These forward link slots T1 to T4 and reverse link slots R1 to R4 form a pair, and thereby four bidirectional radio channels CH1 to CH4 are configured.

When performing data transmission, these radio channels CH1 to CH4 are fixedly assigned to predetermined mobile stations MS1 to MS4, as shown in FIG. 3, for example. The correspondence between the mobile stations MS1 to MS4 and the radio channels CH1 to CH4 for this fixed allocation is stored in advance in the memory table. On the other hand, when it is necessary to retransmit the data, the radio channels CH1 to CH4 are connected to the mobile station MS as shown in FIG.
It is possible to assign to any of 1 to MS4. That is, the radio channel C for the mobile stations MS1 to MS4
As for the allocation of H1 to CH4, the pre-assign method is used at the time of transmission, and the demand assign method is used when it is necessary to retransmit the data.

In order to allocate a retransmission channel by the demand assign method, the base station BS1 monitors the usage status of each of the wireless channels CH1 to CH4 and finds the number of vacant wireless channels required for retransmission by this monitoring. By.

The base station used in the above system is constructed as follows. FIG. 4 is a circuit block diagram showing a main configuration of the base station. In the figure, a wireless carrier signal sent from a mobile station (not shown) via a wireless channel is received by an antenna 1 and then input to a receiving circuit (RX) 3 via a high frequency switch circuit (SW) 2. The frequency is converted into a reception intermediate frequency signal or a baseband signal by mixing with the reception local oscillation signal output from the frequency synthesizer (SYN) 4. Then, this received signal is an A / D signal including a low pass filter.
After being sampled in the converter 6, it is input to the digital demodulation circuit (DEM) 7.

The digital demodulation circuit 7 establishes frame synchronization and bit synchronization for the received signal and then performs digital demodulation processing. The baseband digital demodulation signal obtained by this demodulation processing is a time division multiple access circuit ( TDMA) 8 and the time slot destined for itself is separated and extracted for each frame.
The frame synchronization and bit synchronization information obtained by the digital demodulation circuit 7 is input to the control circuit 20.

The digital demodulated signal output from the TDMA circuit 8 is an error correction code decoding circuit (CH-CO).
D) 9 is input and is subjected to error correction decoding processing. If the error-correction-decoded digital demodulated signal is a voice signal, the voice signal is converted into a voice code decoding circuit (S
P-COD) 10 is further subjected to voice decoding processing,
It is sent from the line interface circuit (I / F) 11 to the control lines CS (not shown) to the wired lines CL1 to CLn. On the other hand, if the digital demodulated signal output from the error correction code decoding circuit 9 is data sent from a data terminal device such as a personal computer, this data passes through the voice code decoding circuit 10 as it is,
From the line interface circuit (I / F) 11 to the control station CS
To the wired lines CL1 to CLn. This digital demodulated signal is sent from the control station CS to a data terminal device such as a telephone device or a personal computer (not shown) of a communication partner via the wired public network NW.

On the other hand, from the telephone equipment or the data terminal equipment of the communication partner, the wired public network NW and the wired lines CL1 to CL1 are connected.
The digital signal arriving via CLn is input to the line interface 11. If the digital signal is a digital voice signal, the digital voice signal is input to the voice code decoding circuit 10 after the acoustic echo is canceled by an echo canceller (not shown), where it is voice coded and then an error correction code. It is input to the decoding circuit 9. On the other hand, if the digital signal is data, the data passes through the echo canceller and voice code decoding circuit 10 as it is and is input to the error correction code decoding circuit 9. In the error correction code decoding circuit 9, error correction coding processing is performed on the digital signal, and the digital signal subjected to the error correction coding is TDM.
It is input to the A circuit 8.

In the TDMA circuit 8, a transmission frame compatible with the TDMA-TDD system is generated, and a process for inserting the digital signal in the time slot assigned to the own device in the transmission frame is performed. This T
The digital signal output from the DMA circuit 8 is subsequently input to the digital modulation circuit (MOD) 12. In the digital modulation circuit 12, a transmission intermediate frequency signal digitally modulated by the digital signal is generated,
This transmission intermediate frequency signal is converted into an analog signal by the D / A converter 13 and then input to the transmission circuit (TX) 5. As a digital modulation method, for example, π / 4
Shifted DQPSK (π / 4 shifted, differentially e
ncoded quadrature phase shift keying) method is used.

In the transmission circuit 5, the modulated transmission intermediate frequency signal is mixed with the transmission local oscillation signal output from the frequency synthesizer 4, and thereby converted into a radio carrier frequency corresponding to a radio communication channel. Then, the radio carrier signal is controlled to a predetermined transmission power level by a transmission power amplifier (not shown) and then transmitted from the antenna 1 to the mobile station (not shown) via the high frequency switch circuit 2.

The control circuit 20 includes, for example, a microprocessor (CPU) as a main control unit,
It is provided with a channel use state determination means 21 and a channel allocation control means 22.

When it is necessary to request the mobile stations MS1 to MS4 to retransmit data during data transmission, the channel use status judging means 21 is in use for the three radio channels for other mobile stations. It is to determine whether it is empty or not.

The channel allocation control means 22 is a mobile station MS.
1 to MS4, or a data transmission request to the mobile stations MS1 to MS4 from the wired public network NW, a predetermined radio channel for these mobile stations MS1 to MS4. C
Allocate H1 to CH4. On the other hand, if it is necessary to request the mobile stations MS1 to MS4 to retransmit data during data transmission, another channel is determined based on the determination result of the usage status of another wireless channel by the channel usage status determination unit 21. It is determined whether or not there are as many free channels as required for retransmission in the wireless channel, and if there are the required number of free channels, the mobile station issues a retransmission request to perform data retransmission using these free channels. Send to. If the required number of empty channels does not exist, the mobile station transmits a retransmission request to the mobile station to retransmit using the wireless channel during data transmission.

Next, the data retransmission operation by the above system will be described by taking the case where the base station BS1 is performing data communication with the mobile station MS1 as an example. Figure 5
And FIG. 6 is a flowchart showing a retransmission control procedure by the base station BS1 and its control content.

It is assumed that the mobile station MS1 is now transmitting the data Da using the radio channel CH1 as shown in FIG. 7A, for example. At this time, the base station BS1 controls the data reception from the mobile station MS1 in step 4a of FIG. In this data reception control, the radio channel CH being used for communication with the mobile station MS1.
The received electric field strength and the data error rate of No. 1 are detected, and based on the detection result, it is determined whether it is necessary to request the retransmission of data. Then, when it is not necessary to request the retransmission of the data, the process directly proceeds from step 4b to another control routine. The detection results of the received electric field strength and the data error rate can also be used for diversity control, burst error prediction, and the like.

By the way, the error rate of the received data Da increases due to the influence of fading, etc.
Suppose that it is determined that it is necessary to request the retransmission of. Then, the base station BS1 makes a transition from step 4b to step 4c, where all the radio channels CH1 to C are first
Determine the usage status of H4. And all wireless channels C
If all of H1 to CH4 are in use, step 4d
To Step 4e, the mobile station MS1 sends a request to the mobile station MS1 for instructing retransmission using the radio channel CH1 being used for data transmission.

Therefore, in this case, the mobile station MS1 suspends the transmission of the untransmitted data even if there is untransmitted data, and instead resends the data Da instructed by the resend request. The transmission data to be retransmitted and the transmission data that has not been sent are stored in the transmission buffer memory.

On the other hand, the radio channels CH1 to CH4
Suppose you have found a free channel in. In this case, the base station BS1 moves to step 4f and first determines here whether or not the number of wireless channels in use is only one channel, and if there is only one channel, determines that there are three or more empty channels. Then, subsequently, in step 4g, it is determined whether or not the retransmission data is less than or equal to 3 slots. When it is determined that there are three empty channels and the retransmission data is less than or equal to three slots, an empty channel corresponding to the number of slots required for retransmission is selected from the above empty channels in step 4h, and this wireless channel is selected. The mobile station MS1 is requested to retransmit using.

For example, if the radio channels CH2 to CH4 are empty channels and the number of slots required for retransmission is one slot, the radio channel CH2 is selected and the retransmission using this radio channel CH2 is requested. Therefore, the mobile station MS1 that has received this retransmission request newly captures the radio channel CH2 as a retransmission channel as shown in FIG. 7B, and this radio channel CH2
To send the data Da to be retransmitted to the base station BS1. At this time, the transmission of the transmission data Db that has not been transmitted is
Using the radio channel CH1 for data transmission, the retransmission operation is continuously performed in parallel.

If the wireless channels CH2 to CH4 are empty channels and the number of slots required for retransmission is two slots, the wireless channels CH2 and CH3 are selected and the retransmission using these wireless channels CH2 and CH3 is performed. To request. Therefore, the mobile station MS1 that has received this retransmission request newly captures the radio channels CH2 and CH3 as retransmission channels, as shown in FIG. 7C, and uses these radio channels CH2 and CH3 to retransmit. Of the data Da and Db are transmitted to the base station BS1.
At this time, the transmission of the transmission data Dc that has not been transmitted is continuously performed in parallel with the above-described retransmission operation using the wireless channel CH1 for data transmission.

Similarly, the radio channels CH2 to CH4 will be described below.
Is a vacant channel and the number of slots required for retransmission is 3, the wireless channels CH2 to CH4 are selected and retransmission using these wireless channels CH2 to CH4 is requested. Therefore, the mobile station MS1 that has received this retransmission request newly captures the wireless channels CH2 to CH4 as retransmission channels, as shown in FIG. 7D, and uses these wireless channels CH2 to CH4 as the retransmission target. Of the data Da, Db, Dc are transmitted to the base station BS1.

On the other hand, it is assumed that there are three empty radio channels, but the number of slots required for retransmission is four. In this case, the base station BS1 moves to step 4i, where the vacant radio channels CH2 to CH4 are mentioned.
In addition to this, the mobile station MS1 selects the radio channel CH1 being used for data transmission, and these four radio channels CH1
A retransmission request is transmitted to the mobile station MS1 to retransmit data using all of CH4. Therefore, the mobile station MS1 newly captures the radio channels CH2 to CH4 and retransmits the data Dc, Db, Da as shown in FIG. 7E in response to the retransmission request, and retransmits the untransmitted data by the radio channel CH1. The transmission is temporarily stopped and the data Dd is retransmitted on the same channel CH1.

On the other hand, if it is determined in step 4f that the number of wireless channels in use is not one, the base station BS1 moves to step 4j and the number of wireless channels in use is two. Or not. If the number of used channels is 2, that is, if the number of free channels is 2, then step 4k
Then, it is determined whether or not the retransmission data is equal to or less than 2 slots. When it is determined that there are two empty channels and the retransmission data is equal to or less than two slots, an empty channel corresponding to the number of slots required for retransmission is selected from the above empty channels in step 4l, and this wireless channel is selected. Retransmission using mobile station MS1
To request.

At this time, it is assumed that there are two free radio channels, but the number of slots required for retransmission is three or more. In this case, the base station BS1 proceeds to step 4m, where the mobile station MS1 selects the radio channel CH1 being used for data transmission in addition to the above-mentioned two free radio channels and uses these three radio channels. The mobile station MS to send a retransmission request to retransmit the data.
Send to 1.

Similarly, in the above step 4j,
When it is determined that the number of wireless channels in use is not two, the base station BS1 proceeds to step 4n to determine whether the number of wireless channels in use is three. If the number of used channels is three, that is, if the number of free channels is only one,
The process proceeds to step 4o, where it is determined whether or not the retransmission data is one slot or less. When it is determined that there is one empty channel and the retransmission data is one slot or less, the one empty channel is selected in step 4p, and the mobile station MS1 is requested to retransmit using this wireless channel. .

At this time, it is assumed that there is one free radio channel, but the number of slots required for retransmission is two or more. In this case, the base station BS1 proceeds to step 4q, where the mobile station MS1 selects the radio channel CH1 being used for data transmission in addition to the above-mentioned one radio channel which is available and uses these two radio channels. The mobile station MS to send a retransmission request to retransmit the data.
Send to 1.

As described above, in this embodiment, the base stations BS1 to BS1.
When BSn determines that it is necessary to retransmit the data to the mobile stations MS1 to MSm, the channel usage status determining means 21 determines the usage status of all wireless channels. If there are more free channels than required for retransmission, the mobile station is notified of the request to retransmit the data using these free channels, while there are free channels but it is necessary for retransmission. If the number of channels is less than the above, the mobile station is notified of a request to retransmit the data using the idle channel and the radio channel being used by the mobile station.

Therefore, according to the present embodiment, even if a radio channel to be assigned to another mobile station is required to be retransmitted during data transmission, if this radio channel is free at that time, this The wireless channel will be assigned for retransmission. For this reason, it is possible to continue data transmission on the wireless channel assigned to the own station during transmission and to retransmit data on an idle channel in parallel with the data transmission. Therefore, the data can be retransmitted without interrupting the transmission of the untransmitted data, and the transmission efficiency can be increased accordingly.

When the number of channels required for retransmission is less than the number of empty channels, data can be retransmitted by using a wireless channel for transmitting untransmitted data in addition to the above empty channels. Therefore, the retransmitted data can be transmitted relatively quickly without causing a large transmission delay. That is, it is possible to reliably execute the transmission control that prioritizes the retransmission procedure.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the system adopting the so-called pre-assign system in which the predetermined radio channels CH1 to CH4 are fixedly allocated to the mobile stations MS1 to MS4 at the time of data transmission has been described as an example. MS1-MS4 and each radio channel CH1-
The present invention may be applied to a system adopting a so-called demand assign method in which the correspondence relationship of allocation with CH4 is not predetermined.

In the above embodiment, the case where the base station determines the use status of the radio channel and assigns the radio channel for retransmission is explained as an example. However, each mobile station determines the use status of the radio channel. And a wireless channel for retransmission may be assigned. Further, the base station may determine the usage status of the wireless channel, notify each mobile station of the determination result, and each mobile station may allocate a wireless channel for retransmission. The configuration may be reversed.

In the above embodiment, the case where the present invention is applied to the retransmission at the time of data transmission has been described. However, when the retransmission procedure is adopted for the transmission of the voice signal, the retransmission of the voice transmission is performed. The present invention may be applied. further,
In the above embodiment, the system of the type capable of selectively performing both voice transmission and data transmission has been described as an example.
It may be applied to a type of system that only performs data transmission, or may be applied to a type of system that only performs voice transmission. Further, in a system of a type capable of selectively performing both voice transmission and data transmission, when the present invention is applied only to retransmission during data transmission, the error correction code decoding circuit 9 and the voice code decoding circuit 10 is provided with a changeover switch, and by changing this changeover switch, the voice code decoding circuit 1 is provided between the error correction code decoding circuit 9 and the line interface circuit 11 during data transmission.
It may be configured to transfer data without passing 0.

Further, in the above embodiment, TDMA-TDD is used.
Although the case where the present invention is applied to the method has been described as an example,
The present invention can also be applied to a system adopting other multiple access methods such as TDMA-FDD method and CDMA method. In addition, the determination procedure and the content of the means for determining the usage status of the wireless channel, the control procedure and control content of the wireless channel allocation control means, the configuration of the wireless communication device, the data retransmission procedure, the transmission format, etc. Various modifications can be implemented without departing from the above.

[0052]

As described above in detail, in the mobile communication system, wireless communication device and wireless data transmission method of the present invention,
When performing the retransmission procedure, it is determined whether or not there are as many free wireless channels as necessary to perform the above retransmission procedure among multiple wireless channels, and the number of radio channels required to execute the retransmission procedure is determined. When it is determined that there is a vacant wireless channel, this vacant wireless channel is assigned for the above-mentioned retransmission procedure.

Therefore, according to the present invention, untransmitted data can be transmitted and data can be retransmitted in parallel with the transmission, so that the reduction in the transmission efficiency due to the retransmission can be suppressed as much as possible, and moreover, it is dedicated to the retransmission. A mobile communication system and a radio used in this system capable of improving transmission efficiency in a state where retransmission is not required, since all radio channels can be assigned to mobile stations for transmission without providing radio channels A communication device and a wireless data transmission method can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a digital mobile communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a transmission format used in the system shown in FIG.

FIG. 3 is a diagram showing a correspondence relationship of radio channel allocation to mobile stations.

4 is a circuit block diagram showing a configuration of a base station in the system shown in FIG.

5 is a flowchart showing the retransmission channel allocation control procedure by the base station shown in FIG. 4 and the first half of the control contents.

FIG. 6 is a flowchart showing the retransmission channel allocation control procedure by the base station shown in FIG. 4 and the latter half of the control contents.

FIG. 7 is a diagram for explaining the operation of the mobile station that has received a retransmission request under the control shown in FIGS. 5 and 6 in the base station.

[Explanation of symbols]

BS1, BS2, ... Base station MS1, MS2, ... Mobile station CL1, CL2, ... Wired line CS ... Control station NW ... Wired public network CH1-CH4 ... Radio channel 1 ... Antenna 2 ... High frequency switch circuit (SW) 3 ... Reception Circuit (RX) 4 ... Frequency synthesizer (SYN) 5 ... Transmission circuit (TX) 6 ... A / D converter 7 ... Digital demodulation circuit (DEM) 8 ... Time division multiple access circuit (TDMA) 9 ... Error correction code decoding circuit (CH-COD) 10 ... Voice code decoding circuit (SP-COD) 11 ... Line interface circuit (I / F) 12 ... Digital modulation circuit (MOD) 13 ... D / A converter 14 ... Memory 20 ... Control circuit 21 ... Channel usage status judging means 22 ... Channel allocation control means

Claims (6)

[Claims] 1. A base station and a plurality of mobile stations are multiple-accessed via a plurality of radio channels, and radio data transmission is performed between the connected base station and the mobile station according to a sequence having a retransmission procedure. In a mobile communication system having a function of performing, when executing the retransmission procedure, it is determined whether or not there are a sufficient number of empty wireless channels required to execute the retransmission procedure among the plurality of wireless channels. And a channel use state determining means for determining the number of available wireless channels to be used for executing the retransmission procedure. A mobile communication system comprising: 2. The channel allocation control means allocates a wireless channel fixedly set in advance to the mobile station among the plurality of wireless channels when starting wireless data transmission, and during the wireless data transmission. When executing the resending procedure, an empty wireless channel is selected from a plurality of wireless channels which are fixedly set in advance for other mobile stations, based on the determination result of the channel use state determining means. The mobile communication system according to claim 1, wherein the mobile communication system is assigned to the mobile station. 3. The channel allocation control means, when the channel use state determining means determines that there are not enough free wireless channels for executing the retransmission procedure, the wireless channel being used for wireless data transmission. 3. The mobile communication system according to claim 1, wherein the transmission by the channel is temporarily suspended, and a required number of wireless channels including the used wireless channel and the idle wireless channel are allocated for the retransmission procedure. . 4. A base station and a plurality of mobile stations are multiple-accessed via a plurality of radio channels, and radio data transmission is performed between the connected base station and the mobile station according to a sequence having a retransmission procedure. In a wireless communication device used as the base station in a mobile communication system having a function to perform, when performing the retransmission procedure, a number of vacant spaces required to execute the retransmission procedure in the plurality of wireless channels. Channel use state determining means for determining whether or not there is a wireless channel, and if the channel use state determining means determines that there are as many free wireless channels as necessary to execute the retransmission procedure. And a resending request sending means for sending a request for resending using the vacant wireless channel to a corresponding mobile station. Apparatus. 5. A base station and a plurality of mobile stations are multiple-accessed via a plurality of radio channels, and radio data transmission is performed between the connected base station and the mobile station according to a sequence having a retransmission procedure. In a wireless communication device used as the mobile station in a mobile communication system having a function to perform, when executing the retransmission procedure, a number of vacant spaces required to execute the retransmission procedure in the plurality of wireless channels. Channel use state determining means for determining whether or not there is a wireless channel, and if the channel use state determining means determines that there are as many free wireless channels as necessary to execute the retransmission procedure. And a retransmission request transmitting means for transmitting to the base station a request for performing retransmission using the free wireless channel. 6. A base station and a plurality of mobile stations are subjected to multiple access via a plurality of radio channels, and radio data transmission is performed between the connected base station and the mobile station according to a sequence having a retransmission procedure. In the wireless data transmission method to be performed, when performing the retransmission procedure, a step of determining whether or not there are a number of empty wireless channels necessary for performing the retransmission procedure in the plurality of wireless channels, When it is determined by this step that there are the number of empty wireless channels required to execute the retransmission procedure, the step of allocating this empty wireless channel for the retransmission procedure is provided. Wireless data transmission method.