JP2001224072A - Base station unit for dsa communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable impartial sharing of frequency bands between a DSA communication system and a CSMA communication system when both communication systems use the same frequency band in common and stably transmits a notice channel (Bch) to prevent out of frame synchronism in the DSA communication system. SOLUTION: In the case that transmission/reception of a burst signal is stopped through the detection of an interference wave at the head of a frame period, when no interference wave is detected continuously for a prescribed period from prescribed timing in the frame period until the end of the frame, a reservation signal to acquire a token for a succeeding frame is transmitted. In the case that no burst signal is transmitted due to the detection of an interference wave and a token is acquired by a succeeding frame, part or all of an area assigned to a random access burst (Rch) in the frame is used for a communication area depending on the stored information amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a centralized control type DS.
A wireless data communication system (DSA communication system) using the A (Dynamic Slot Assign) method and a wireless data communication system (CSMA communication system) using the CSMA (CarrierSense Multiple Access) method of autonomous distributed control use the same frequency band. The present invention relates to a base station device of a DSA communication system used for fair sharing of a frequency band in a shared situation.

Here, in the DSA communication system, a base station manages a frame cycle which is a basic cycle of communication, performs burst allocation to each terminal at the beginning of the frame cycle, and communicates with the base station and each terminal. It is a configuration for performing communication between devices, and standardization is being promoted by a telecommunication standardization organization such as MMAC in Japan and ETSI / BRAN in Europe. CS
The MA communication system has a configuration in which transmission can be started at an arbitrary timing without detecting an interference wave received at a predetermined level or higher without depending on a frame period.
Complies with the recommendations of 2.11. Each of these wireless data communication systems is considered to share the same frequency band during actual operation.

[0003]

2. Description of the Related Art FIG. 9 shows an example of a frame configuration of a DSA communication system. In the figure, a broadcast channel (Bch) for the base station apparatus to perform burst allocation to each terminal apparatus is arranged at the head of the frame. The broadcast channel contains control information such as an assigned terminal number, a start position of a subsequent communication burst, a burst length, and transmission / reception.

[0004] Next, a downlink (D
own-link) and uplink from terminal to base station (Up-li
nk) is placed. The downlink and uplink accommodate one or more communication bursts composed of a control channel (Cch) and a data channel (Dch). Further, one or more random access bursts (Rch) for a new terminal or the like to perform temporary data transmission are allocated to each frame. Here, in one frame, a portion other than those allocated to the broadcast channel (Bch), the downlink and the uplink is defined as a random access burst (Rch), and the length thereof depends on the amount of data allocated to the downlink and the uplink. Fluctuate.

FIG. 10 shows an outline of the operation of the CSMA communication system. In the figure, the horizontal axis indicates time, and the signal transmission status of the base station apparatus and the two terminal apparatuses from the top is shown.
The region of Δt provided before the transmission time 21a to 21f of each data indicates a time for monitoring the presence or absence of an interference wave received at a predetermined level or higher. Before transmitting data, the base station apparatus or the terminal apparatus monitors a received signal from another station, and after confirming that an interference wave received at a predetermined level or more for a predetermined time (Δt) is not detected continuously, the base station apparatus or the terminal apparatus transmits the data. Start sending.

[0008] For example, the terminal device “a” generates traffic immediately at time t 1 and immediately detects an interference wave. If no interference wave is detected for a predetermined time Δt, data transmission can be started thereafter. Similarly, the terminal device b performs interference wave detection when traffic occurs, but the terminal device a
Is transmitting data, the time t at which the transmission ends
2. Data transmission can be started only after a predetermined time Δt during which no interference wave is detected. Thereby, collision of signals can be prevented.

FIG. 11 shows a configuration example of a base station device of a conventional DSA communication system. In the figure, the base station device
A data input / output unit 31 for inputting / outputting data to / from the network, a buffer 32 for storing input data,
A scheduler 33 for determining a frame configuration; a timing management unit 34 for managing transmission / reception timing; a transmission control unit 35 for performing signal transmission control; a transmission unit 36 for performing transmission processing; a reception unit 37 for performing signal reception processing; The system includes a reception control unit 38 for performing reception control and an interference wave detection unit 39 for detecting an interference wave received at a predetermined level or higher.

Data input from the network is stored in a buffer 32 via a data input / output means 31.
Further, control information is added by the transmission control means 35 and transmitted from the transmission means 36 by a downlink communication burst allocated to each terminal device according to an instruction from the scheduler 33.

[0009] Here, the scheduler 33 transmits the information of each terminal device included in the control information of each terminal device input from the reception control means 38 and the information of the buffer 32 of the base station device to each terminal device. Then, burst assignment information such as an assigned terminal number, a start position of a communication burst, and a burst length is instructed to the transmission control means 35. The transmission control unit 35 receives the burst allocation information from the scheduler 33 and generates a frame based on the transmission timing based on the frame period provided from the timing management unit 34. Also,
The burst assignment information is notified from the transmitting means 36 to each terminal device via a broadcast channel (Bch). At this time, within a predetermined time at the head of the frame period, the reception signal of the reception means 37 is monitored by the interference wave detection means 39, and if an interference wave received at a predetermined level or higher is detected, the transmission control means 35 Instructs the transmitting means 36 not to transmit the broadcast channel (Bch) of the frame.

A signal transmitted from each terminal device is received by the receiving means 37. The reception control unit 38 receives the burst allocation information from the scheduler 33, identifies the received signal based on the reception timing based on the frame period provided from the timing management unit 34, and extracts control information and data. The data is output to the network via the data input / output means 31, and the control information is used by the scheduler 33 for burst allocation of the next frame.

FIG. 12 shows a configuration example of a terminal device of a conventional DSA communication system. In the figure, a terminal device includes a data input / output unit 41 for inputting / outputting data to / from an external data processing device, and a buffer 42 for storing input data.
Management means 4 for managing transmission / reception timing
3, a transmission control means 44 for performing signal transmission control and a transmission means 45 for performing transmission processing, a reception means 46 for performing signal reception processing, and a reception control means 47 for performing reception control.

The data input from the data processing device is
The data is accumulated in the buffer 42 via the data input / output unit 41, and the control information is added by the transmission control unit 44.
The transmission control means 44, according to the burst allocation information of the broadcast channel (Bch) input from the reception control means 47,
An uplink communication burst assigned to each terminal device is formed, and transmitted from the transmission unit 45 based on a transmission timing based on a frame period provided from the timing management unit 43.

The signal transmitted from the base station device is received by receiving means 46. The reception control means 47 receives the broadcast channel (Bch) based on the reception timing based on the frame period given from the timing management means 43 and notifies the transmission control means 44 of the uplink burst position assigned to the own station. At the same time, the communication burst addressed to the own station is identified from the downlink burst allocated to each terminal device. The reception control unit 47 extracts data from the identified communication burst addressed to the own station, and outputs the data to the data processing device via the data input / output unit 41.

[0014]

Conventionally, a centralized control type D
The case where different control systems such as the SA system and the autonomous distributed control type CSMA system coexist on the same frequency band has not been studied much. However, in practice, wireless data communication systems (DSA) using different control schemes
A situation in which a communication system and a CSMA communication system share the same frequency band is occurring. For this reason, some organizations are beginning to study a policy of monitoring interference waves from other stations during signal transmission and refraining from transmitting signals when interference waves are detected. However, such a policy alone cannot sufficiently address the following problems.

(First Problem) FIG. 13 shows a conventional DSA.
An outline of the operation when the communication system and the CSMA communication system share the same frequency band will be described. In the figure, time is plotted on the horizontal axis, scales indicate frame divisions in the DSA communication system, and 1 to 6 indicate frame numbers. On the upper side of the time axis, the bandwidth use times 51a to 51 of the DSA communication system
b, and the bandwidth use time 52a to 52h of the CSMA communication system is shown below the time axis. Frames 2-5 in the figure
In this example, the CSMA communication system is communicating at the beginning of the frame, and the DSA communication system will refrain from transmitting signals in order to avoid signal collision.

The DSA communication system uses a broadcast channel (Bc
h), the frame cannot be used unless this broadcast channel can be transmitted. Therefore, at the head position of the frame of the DSA communication system, C
If the SMA communication system is performing communication, transmission of the broadcast channel cannot be performed, so that transmission is stopped for one frame. In FIG. 13, four frames cannot be transmitted continuously.

On the other hand, since the CSMA communication system is of an autonomous distributed control type that does not depend on the frame period, transmission can be started if an interference wave is not detected for a predetermined time Δt at an arbitrary timing. can do.

The DSA communication system usually has at least one random access burst (Rch) in each frame in order to quickly accommodate a newly registered terminal device.
Is assigned. However, if there is no terminal device that uses this random access burst, there is no signal section (shown by broken lines in the band use times 51a and 51b in FIG. 13). Therefore, in the DSA communication system, even when the input traffic amount is large, the time period during which the transmission is stopped constantly exists within the frame period. For this reason,
When CSMA communication systems coexist, there is a possibility that the CSMA communication system will interrupt the non-signal random access burst area of the DSA communication system. In FIG. 13, an interrupt (5
Even after the occurrence of 2a), the CSMA communication system occupies from frame 5 to frame 5, and even if the DSA communication system finally secures the band in frame 6, the CSMA communication system interrupts again (52h), and the transmission of the next frame stops. I have.

Thus, the DSA communication system and the CSM
When the A communication system shares the same frequency band,
The autonomous distributed control type CSMA communication system tends to occupy the frequency band preferentially.
There is a problem that the transmission quality of the A communication system is significantly deteriorated.

FIG. 14 shows a DSA communication system and CSMA.
4 shows a conventional delay time characteristic of a communication system. here,
The case where each communication system operates alone and the case where each communication system shares the same frequency band are shown as evaluation results by computer simulation. In the figure, the horizontal axis indicates the ratio of the total input traffic amount to the total bandwidth capacity, and the vertical axis indicates the average delay time. The simulation conditions are that the frame length is 2 msec and the average transmission speed is
20 Mbps, the number of terminals of the CSMA communication system is 40, and the traffic distribution for burst length 64, 128, 256, 512, 1024, 1516 byte packets is 0.6, 0.06, 0.04, 0.02, 0.2.
The ratio of 5, 0.03 was assumed, and the traffic volume of each communication system was equal when shared.

It can be seen that, when the DSA communication system shares the frequency band with the CSMA communication system, the delay characteristic is greatly deteriorated as compared with the case of the single operation. On the other hand, CSMA
The delay characteristic of the communication system is more improved when the frequency band is shared with the DSA communication system than when the DSA communication system operates alone. This means that despite the same input traffic volume,
This is because the CSMA communication system can easily secure and occupy a band. As described above, when the DSA communication system and the CSMA communication system share the same frequency band, fair sharing of the frequency band is difficult, and unilateral degradation of the characteristics of the DSA communication system is inevitable.

(Second Problem) In a DSA communication system, frame synchronization is achieved by transmitting and receiving a broadcast channel (Bch) between a base station apparatus and a terminal apparatus. Therefore, if transmission of the broadcast channel is continuously stopped, frame synchronization may be lost.

The terminal device usually sets a small aperture window before and after the expected frame start timing in order to avoid erroneous detection of the frame start timing, and performs timing detection only within this window. Further, after the timing of the head of the frame is detected, there is a device for suppressing power consumption by transmitting and receiving only a subsequent broadcast channel and a communication burst addressed to the own station specified by the broadcast channel. In the case of wireless mobile terminals, battery saving by suppressing power consumption is a very important issue, and such ideas are being actively adopted.

However, once the frame is out of frame, the aperture window is released and the timing is detected at all timings in the frame, so that the probability of erroneous detection of the head timing of the frame greatly increases. Furthermore, since power saving cannot be used effectively, it is expected that the power consumption of the terminal device will increase.

FIG. 15 shows that the DSA communication system is CSMA.
It shows the time ratio of the continuous transmission stop state when sharing the same frequency band with the communication system. Here, the relationship between the number of frames Nf and the time rate in a state where the DSA communication system continuously stops transmitting the broadcast channel for Nf frames or more is shown as an evaluation result by computer simulation. The simulation conditions were the same as in the above-described example, and the case where the total of the input traffic was 80% of the bandwidth capacity was taken as an example.

In this simulation, the time rate that cannot be used for more than 6 frames (12 msec) exceeds 10%, and even when the number of forward protection stages for frame synchronization is set to about 5, frame synchronization on the terminal device side is frequently lost. It can be seen that there is a risk of getting up.

According to the present invention, the DSA communication system is a CSMA communication system.
When sharing the same frequency band with a communication system, considering the two problems described above, it is possible to share the frequency band fairly between both communication systems,
DS that can stably transmit a broadcast channel (Bch) to prevent frame synchronization loss in an SA communication system
An object of the present invention is to provide a base station device of the communication system A.

[0028]

According to a first aspect of the present invention, there is provided a base station apparatus for a DSA communication system, wherein when transmission / reception of a burst signal (broadcast channel (Bch)) is interrupted by detection of an interference wave at the beginning of a frame period, the frame is transmitted. If no interference wave is continuously detected for a predetermined time between a predetermined timing in the cycle and the end of the frame, a reservation signal for acquiring a communication right is transmitted in the next frame.

Thus, even when the base station device of the DSA communication system shares the same frequency band with the CSMA communication system, the transmission of the reservation signal eliminates the interruption from the CSMA communication system and grants the communication right of the next frame. Acquisition can be reliably obtained, and loss of frame synchronization due to transmission of the broadcast channel (Bch) can be avoided, and a decrease in throughput can be prevented. However, once the reservation signal is transmitted, CSMA
Since the interruption from the communication system becomes impossible, the predetermined timing for starting the detection of the interference wave for transmitting the reservation signal is appropriately adjusted so that the DSA communication system and the CSMA communication system can share the frequency band fairly.

For example, the predetermined timing is usually set slightly before the end of the frame, and the influence of the reservation signal of the DSA communication system on the CSMA communication system is minimized. When a predetermined number of frames in which neither the burst signal nor the reservation signal can be transmitted continues,
Predetermined timing for performing interference wave detection for transmitting a reservation signal is advanced, and the opportunity to transmit a reservation signal is increased (claim 2).

Since the reservation signal ensures the acquisition of the communication right for the next frame, the interference wave detection process at the beginning of the frame period may be omitted in that frame, and the broadcast channel (Bch) may be transmitted immediately. (Claim 3).

On the other hand, a decrease in throughput may not be avoided only by acquiring the communication right of the next frame by the reservation signal. That is, even if a frame in which neither the burst signal nor the reservation signal can be transmitted continues, and even if the communication right of the frame can be finally obtained, if the random access burst (Rch) to be assigned is no signal, the CS signal is always output.
This is a case where the interruption of the MA communication system is permitted and the communication right of the frame cannot be continuously obtained. In such a case, the configuration of the base station apparatus according to claim 4 or later is effective.

The base station apparatus of the DSA communication system according to claim 4 cannot transmit a burst signal due to interference wave detection,
When a communication right is acquired in a subsequent frame, a part or all of an area allocated to a random access burst (Rch) in the frame is used as a communication area according to the amount of stored information. Accordingly, when sharing the same frequency band with the CSMA communication system, the base station apparatus of the DSA communication system increases the communication area in the subsequent frame even if a frame in which a burst signal cannot be transmitted occurs and data is accumulated. Throughput can be improved.

When the amount of information stored in the information storage means exceeds a predetermined value, the entire area allocated to the random access burst (Rch) is used as the communication area in the frame for which the communication right has been acquired. Further, the communication right of the succeeding frame is acquired (claim 5). That is,
Large amount of stored information, random access burst (Rch)
If the processing cannot be performed in one frame even if the area allocated to is set to 0, the area becomes a communication area until the end of the frame period.
This performs substantially the same function as the reservation signal, and the next frame is not interrupted by the CSMA communication system, and the communication right of the frame can be continuously obtained.

Further, as long as there is an amount of information stored in the information storage means, a part or all of an area allocated to a random access burst (Rch) is used as a communication area over a plurality of frames for which a communication right has been acquired. (Claim 6). The accumulated information amount may be equal to the accumulated information amount of each terminal device.

[0036]

FIG. 1 shows an embodiment of a base station apparatus of a DSA communication system according to the present invention. The base station apparatus according to the present embodiment has a configuration capable of simultaneously executing the functions described in claims 1 and 4, but the functions corresponding to the respective claims may be individually executed. It should be noted that the terminal device for the base station device of the present invention can be handled with the conventional configuration.

In the figure, a base station device comprises a data input / output means 1 for inputting / outputting data to / from a network,
A buffer 2 for storing input data, a scheduler 3 for determining a frame configuration, a timing management unit 4 for managing transmission / reception timing, a transmission control unit 5 for performing signal transmission control, a transmission unit 6 for performing transmission processing, Receiving means 7 for performing reception processing of the above, reception control means 8 for performing reception control, interference wave detecting means 9 for detecting an interference wave received at a predetermined level or higher, and reservation for acquiring a communication right in the next frame. Reservation signal generating means 10 for generating a signal;
Rch allocation control means 11 for controlling allocation of random access bursts (Rch).

The data input from the network is stored in the buffer 2 via the data input / output means 1, further added with control information by the transmission control means 5, and assigned to each terminal device in accordance with an instruction from the scheduler 3. It is transmitted from the transmission means 6 by a communication burst of the downlink.

Here, the scheduler 3 performs the control of each terminal device based on the information of the buffer of each terminal device included in the control information of each terminal device input from the reception control means 8 and the information of the buffer 2 of the base station device. Then, burst assignment information such as an assigned terminal number, a start position of a communication burst, and a burst length is instructed to the transmission control means 5. The transmission control means 5 receives the burst allocation information from the scheduler 3 and generates a frame based on the transmission timing based on the frame period provided from the timing management means 4. Further, the burst assignment information is notified from the transmitting means 6 to each terminal device on a broadcast channel (Bch). At this time, the transmission control means 5 and the interference wave detection means 9 instruct the transmission means 6 not to transmit the broadcast channel (Bch) of the frame when the interference wave is detected within a predetermined time at the beginning of the frame period. I do.

The signal transmitted from each terminal device is received by the receiving means 7. The reception control means 8 receives the burst assignment information from the scheduler 3, identifies the received signal based on the reception timing based on the frame period provided from the timing management means 4, and extracts control information and data. The data is output to the network via the data input / output means 1, and the control information is transmitted to the scheduler 3.
Is used for burst allocation of the next frame. The basic operations related to transmission and reception described above are the same as those of the conventional base station apparatus.

This embodiment is characterized in that the transmission control means 5 and the interference wave detection means 9 detect an interference wave within a predetermined time from the beginning of the frame period and stop transmitting the broadcast channel (Bch), or There is a process in a frame subsequent to that frame, and the reservation signal generation unit 10 or the Rch allocation control unit 11 starts up and performs a required process. The function and detailed processing procedure of the reservation signal generating means 10 will be described with reference to FIGS. The function and the detailed processing procedure of the Rch assignment control means 11 will be described with reference to FIGS.

(Processing Procedure of Base Station Apparatus of DSA Communication System According to Claim 1) FIG.
4 shows a processing procedure of a base station apparatus of the communication system A. Less than,
A description will be given also with reference to the configuration of the base station apparatus shown in FIG.

The transmission control means 5 of the base station apparatus determines whether the interference wave detection means 9 does not detect the interference wave for a predetermined time from the beginning of the frame period (S1), Is not detected, the broadcast channel (B
ch) (S2), and subsequently, transmission / reception of communication bursts (Cch, Dch) for one frame is performed (S3). On the other hand, when the interference wave is detected during the predetermined time, the transmission of the broadcast channel (Bch) is stopped, and the reservation signal generating means 10 is activated (S4).

The reservation signal generating means 10 detects the interference wave for a predetermined time after the predetermined timing based on the frame period provided from the timing management means 4 in the frame in which the transmission of the broadcast channel (Bch) is stopped. It is determined whether the means 9 does not detect an interference wave (S
5) When the interference wave is not detected continuously for a predetermined time, a reservation signal is generated and transmitted from the transmitting means 6 (S6). On the other hand, when the interference wave is detected during the predetermined time, the above processing is repeated until the end of the frame, and between the predetermined timing and the end of the frame, when the time during which the interference wave is not detected does not continue for the predetermined time, , The reservation signal cannot be transmitted, and the process ends (S7).

An outline of the operation when the DSA communication system and the CSMA communication system using such a base station apparatus share the same frequency band will be specifically described with reference to FIG.

In FIG. 5, the horizontal axis represents time, and the scale is DS.
Frame divisions in the communication system A, 1 to 6 indicate frame numbers. Band utilization times 61a to 61c of the DSA communication system are shown above the time axis, and bandwidth utilization times 62a to 62g of the CSMA communication system are shown below the time axis.

In frame 1, when the DSA communication system does not detect an interference wave for a predetermined time Δt, transmission of the broadcast channel (Bch) and communication burst (Cch, Dc)
h) is transmitted and received (61a). However, when the random access burst (Rch) assigned in advance becomes no signal as indicated by the broken line in the band use time 61a, an interrupt from the CSMA communication system is generated (62a).

In frame 2, an interference wave is detected by the communication (62b) of the CSMA communication system, and the DSA communication system stops transmitting the broadcast channel (Bch). At this time, interference wave detection is performed from a predetermined timing M in frame 2 (for example, at the end of 90% of the frame), and if no interference wave is detected for a predetermined time Δt, the reservation signal 63a
And continues to the end of frame 2. Thereby, in frame 3, the DSA communication system can acquire the communication right (61b). The reservation signal may be a signal that continues to the end of the frame, or may be transmitted in bursts at intervals that can eliminate interruption from the CSMA communication system.

However, even in frame 3, the CSMA communication system interrupts the random access burst (Rch) assigned in advance because there is no signal (62c).
In frame 4, the DSA communication system transmits a broadcast channel (Bc
h) cannot be sent. At this time, interference wave detection is performed from a predetermined timing M in the frame 4. However, the interference wave is detected by the communication (62d) of the CSMA communication system, and after the end of the communication, the interference wave is detected for a predetermined time Δt. The transmission of the reservation signal 63b is started after the disappearance, and continues until the end of the frame 4. Thereby, in frame 5, the DSA communication system can acquire the communication right again (61c). When the communication of the CSMA communication system continues until the end of the frame, or when the frame ends within a predetermined time Δt after the end of the communication, no reservation signal is transmitted.

In frame 5, despite the fact that the communication right of frame 4 could not be obtained, the input traffic is small and the area of the random access burst (Rch) with no signal is large. Thereby, the communication right can be easily transferred from the DSA communication system to the CSMA communication system. In frame 6, due to the communication (62f, 62g) of the CSMA communication system, the DSA communication system cannot transmit the broadcast channel (Bch) and cannot transmit the reservation signal from a predetermined timing M to the end of the frame.

As described above, even when the base station apparatus of the DSA communication system shares the same frequency band with the CSMA communication system, the transmission of the reservation signal eliminates the interruption from the CSMA communication system, and the communication right of the next frame. Can be acquired preferentially.

However, there are cases where the reservation signal cannot be transmitted as in the case of frame 6 in FIG. 5, and in some cases, the communication right cannot be continuously obtained in a plurality of frames and the reservation signal cannot be transmitted. As a method to cope with such a case, for example, the predetermined timing M for starting the detection of the interference wave for transmitting the reservation signal is made variable. Usually, the predetermined timing M is set slightly before the end of the frame (for example, at the end of 95% of the frame), and the broadcast channel (Bc
h) When a predetermined number of frames in which neither the reservation signal nor the transmission of the reservation signal can be transmitted continues, the predetermined timing M is advanced (for example, at the end of 90% of the frame), so that the opportunity to transmit the reservation signal is increased. For this purpose, the reservation signal generation means 10 counts the number of frames for which the reservation signal could not be transmitted, and when the number reaches a predetermined number, sets a predetermined timing M earlier so that the reservation signal can be transmitted or the broadcast channel can be transmitted. If (Bch) can be transmitted, the count value is reset (claim 2).

In the next frame after the transmission of the reservation signal, the interference wave detection process at the beginning of the frame period may be omitted, and the broadcast channel (Bch) may be transmitted immediately. Therefore, when the reservation signal generation unit 10 transmits the reservation signal, it notifies the transmission control unit 5 and simplifies the processing in the next frame.

(Processing Procedure of Base Station Apparatus of DSA Communication System According to Claim 4) FIG.
4 shows a processing procedure of a base station apparatus of the communication system A. Less than,
A description will be given also with reference to the configuration of the base station apparatus shown in FIG.

The transmission control means 5 of the base station apparatus determines whether the interference wave detection means 9 does not detect the interference wave for a predetermined time from the beginning of the frame period (S11), Is not detected, the broadcast channel (B
ch) is transmitted (S12). At this time, the transmission control means 5
Determines whether there is a frame for which the broadcast channel (Bch) could not be transmitted for a predetermined number of frames before that (S13), and if there is such a frame, activates the Rch allocation control means 11 (S14). ). On the other hand, when the interference wave is detected during the predetermined time, the transmission of the broadcast channel (Bch) is stopped, and the history is stored in the transmission control means 5 (S
16).

The Rch allocation control means 11 performs random access burst (Rch) according to the amount of information stored in the buffer 2 and the amount of information stored in each terminal device obtained from the reception control means 8.
The scheduler 3 is controlled so that a part or all of the area allocated to is used as the communication area (S15). For example, if there is no stored data, the area allocated to the random access burst (Rch) is left as it is, and if there is stored data, part or all of the area allocated to the random access burst (Rch) is used as a communication area.

FIG. 4 shows a specific example of the condition S13 for starting the Rch allocation control means 11 and the processing S15 according to the amount of stored information. The transmission control means 5 of the base station apparatus sets 0 to N (N is 1
A counter for counting values up to the above integer), and depending on whether the broadcast channel (Bch) has been transmitted (S21),
Decrements or increments a counter. That is, when the broadcast channel (Bch) can be transmitted, if the current counter value n is 1 or more, the counter value n is decremented by 1 (S22, S23). Further, when the broadcast channel (Bch) cannot be transmitted, if the current counter value n is smaller than N, the counter value n is incremented by 1 (S24, S25).

When the broadcast control channel 5 is able to transmit the broadcast channel (Bch), if the counter value n is 0 (S2
2) At least the broadcast channel (Bc
h) has been transmitted, and the scheduler 3 is caused to perform normal burst allocation without activating the Rch allocation control means 11. If the counter value n is 1 or more, the broadcast channel (Bch) cannot be transmitted in a past frame, and data may be accumulated in the base station device and the terminal device. Then, the transmission control means 5 activates the Rch allocation control means 11,
Processing for using an area allocated to a random access burst (Rch) as a communication area is performed, and the counter value n is decremented.

The Rch allocation control means 11 determines the amount of information stored in the buffer 2 and the amount of information stored in each terminal device obtained from the reception control means 8 (S26). The area allocated to the access burst (Rch) is used as a communication area (S27). At this time, when the entire area allocated to the random access burst (Rch) is used as the communication area, the communication right can be continuously obtained even in the next frame. Further, if the counter value n is 1 or more in the next frame, the Rch allocation control means 11 is started again and the same processing is repeated.

If the amount of stored information is 0 or an amount that can be processed in a region allocated to a normal downlink and uplink, the Rch allocation control means 11 allocates a random access burst (Rch) as usual. At this time, the counter value n of the transmission control means 5 is reset to 0 (S2
8). With this, even if a frame in which the broadcast channel (Bch) cannot be transmitted continues and the counter n has a large value, if the accumulated information amount can be processed in one frame with 0 or a small value, the Rch allocation control unit 11 can be used in the next frame and thereafter. It can be prevented from being started.

Here, assuming that N = 1, the area allocated to the random access burst (Rch) is used as the communication area when the broadcast channel (Bch) cannot be transmitted in the immediately preceding frame. At this time, since the counter value n becomes 0, the amount of stored information is large, and the entire area allocated to the random access burst (Rch) is used as a communication area, and the broadcast channel (Bch) is continuously transmitted even in the next frame. Even if done, in the next frame R
The channel assignment control means 11 is not activated, and the random access burst (Rch) is assigned normally.

When N is set to a value of 2 or more, frames for which the broadcast channel (Bch) could not be transmitted are integrated, and then a plurality of frames that can transmit the broadcast channel (Bch) are used for random access burst (Rch). Can be controlled to be used as the communication area. However, as described above, only when there is stored data.

The outline of the operation when the DSA communication system and the CSMA communication system using such a base station apparatus share the same frequency band will be specifically described with reference to FIG.

In FIG. 6, time is plotted on the horizontal axis, and the scale is D
Frame breaks in the SA communication system, 1 to 6 indicate frame numbers. Band utilization times 71a to 71d of the DSA communication system are shown above the time axis, and band utilization times 72a to 72e of the CSMA communication system are shown below the time axis.
Is shown.

In the frame 1, the DSA communication system performs communication during the band use time 71a. However, since the random access burst (Rch) assigned in advance has no signal,
The CSMA communication system is interrupting (72a). In frame 2, communication of the CSMA communication system (72b)
As a result, the DSA communication system cannot transmit the broadcast channel (Bch), and the transmission control means 5 increments the counter.

In frame 3, the DSA communication system acquires the communication right and transmits the broadcast channel (Bch) (71).
b). At this time, since the counter value n becomes 1 or more, Rch
The allocation control means 11 is activated and uses an area allocated to a random access burst (Rch) in the frame according to the amount of stored information as a communication area (73a). As a result, data stored in the base station device and the terminal device because frame 2 could not be used can be transmitted and received, and the throughput can be improved.

If the communication is used up to the end of the frame 3, the CSMA communication system cannot interrupt,
In the next frame 4, the DSA communication system can acquire the communication right (71c). Therefore, even if the DSA communication system cannot acquire the communication right over a plurality of frames and a large amount of data is accumulated, the entire area allocated to the random access burst (Rch) is used as the communication area. The communication right once obtained can be continuously obtained.

As described above, when the base station apparatus of the DSA communication system shares the same frequency band with the CSMA communication system, even if a frame in which the communication right cannot be acquired continues, data is transmitted in the frame in which the communication right is acquired. Transmission and reception can be performed intensively, and throughput can be improved.
However, even if the communication right is continuously obtained from frame 3 as in frame 4 or the random access burst (Rch) area 73b is used as the communication area as in frame 6, if the transmission / reception data is small, the frame is not transmitted. A signalless area is generated in the CSMA communication system, and the communication right can be transferred to the CSMA communication system.

The operation outlines shown in FIGS. 5 and 6 described above are a process for acquiring the communication right of the next frame using the reservation signal and a process for using the area allocated to the random access burst (Rch) as the communication area. Although each is used alone, a synergistic effect can be obtained by combining both. In other words, when the DSA communication system cannot transmit the broadcast channel (Bch) and continues to transmit frames that cannot transmit the reservation signal, a large amount of data is accumulated, but the transmission of the reservation signal acquires the communication right of the frame. In a frame in which the communication right has been once obtained, the entire region allocated to the random access burst (Rch) is used as a communication region, so that the communication right of the next frame can be further obtained and the throughput can be improved. .

[0070]

As described above, according to claims 1 to 3,
When the base station device of the SA communication system stops transmitting and receiving a burst signal due to interference wave detection at the beginning of a frame period, it transmits a reservation signal until the end of the frame, thereby eliminating an interruption of the CSMA communication system. Then, the acquisition of the communication right for the next frame can be ensured. In addition, when a frame in which the reservation signal cannot be transmitted continues, the timing of detecting an interference wave for transmitting the reservation signal is advanced, and the transmission of the reservation signal is facilitated, so that acquisition of the communication right of the next frame is ensured. Can be Also, in a frame obtained by transmitting a reservation signal, by starting transmission and reception of a burst signal without performing interference wave detection, the area used for communication is increased and the throughput can be improved.

The base station apparatus of the DSA communication system according to claims 4 to 7 cannot transmit / receive a burst signal, and when acquiring a communication right in a subsequent frame, the base station apparatus allocates an area allocated to a random access burst (Rch) of that frame. By using a part or the whole as a communication area, accumulated data can be transmitted and received intensively, and throughput can be improved. In particular, when the amount of stored information is large, by using the entire area allocated to the random access burst (Rch) as the communication area, the communication right once obtained can be continuously obtained in the next frame. Throughput can be improved. In addition, as long as the amount of accumulated information is present, throughput can be improved by using an area allocated to a random access burst (Rch) in a continuous frame as a communication area.

As described above, the base station apparatus of the DSA communication system according to claims 1 to 3 can easily acquire the frame communication right even when the same frequency band is shared with the CSMA communication system, and prevent frame synchronization loss. Can be transmitted stably on the broadcast channel (Bch). Further, D in claims 4 to 7
The base station apparatus of the SA communication system can intensively transmit and receive data in a frame for which a communication right has been once obtained, and can improve throughput. Therefore, by combining both, the DSA communication system and the CSM
The A communication system enables stable transmission of the broadcast channel (Bch) while fairly sharing the frequency band, and further improves the throughput of the entire system.

FIG. 7 shows delay time characteristics of the DSA communication system and the CSMA communication system to which the present invention is applied. Here, the case where each communication system operates alone and the case where each communication system shares the same frequency band,
This is shown as an evaluation result by computer simulation.

In the figure, the horizontal axis shows the ratio of the total input traffic amount to the total bandwidth capacity, and the vertical axis shows the average delay time. The simulation condition is that the frame length is 2 m
sec, average transmission rate is 20 Mbps, number of terminals of CSMA communication system is 40, burst length is 64, 128, 256, 512, 1024, 1
Traffic distribution for 516-byte packets is 0.6,0.
06, 0.04, 0.02, 0.25, 0.03, when sharing, the traffic volume of each communication system is assumed to be equal, and the predetermined timing to start interference wave detection for transmission of a reservation signal is set to a position 1.8 msec from the beginning of the frame, It is assumed that the maximum value N of the counter value n used for random access burst (Rch) allocation control is 16. As shown in the figure, the DSA communication system to which the present invention is applied is greatly improved as compared with the conventional characteristics shown in FIG. 14, and the frequency band is fairly shared between the DSA communication system and the CSMA communication system. You can see that it is done.

FIG. 8 shows a continuous transmission stop state rate when the DSA communication system to which the present invention is applied shares the same frequency band with the CSMA communication system. Here, the relationship between the number of frames Nf and the time rate in which the DSA communication system continuously stops transmitting the broadcast channel for Nf frames or more is shown as an evaluation result by computer simulation. The simulation conditions were the same as in the previous example, and the total input traffic was 80% of the bandwidth capacity.
% Is taken as an example. FIG. 8 also shows the conventional characteristics shown in FIG. 15 for reference.

According to the present invention, the probability of occurrence of a situation where the DSA communication system cannot be used continuously for several frames can be reduced, and the stability of frame synchronization on the terminal device side can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a base station apparatus of a DSA communication system according to the present invention.

FIG. 2 is a flowchart showing a processing procedure of the base station apparatus of the DSA communication system according to claim 1.

FIG. 3 is a flowchart showing a processing procedure of the base station apparatus of the DSA communication system according to claim 4.

FIG. 4 is a flowchart showing a specific example of a condition S13 activated by the Rch allocation control means 11 and a process S14 according to the amount of stored information.

FIG. 5 is a view for explaining an outline of operation when the invention of claim 1 is applied.

FIG. 6 is a diagram for explaining an outline of operation when the invention of claim 4 is applied.

FIG. 7 shows a DSA communication system and a CSM to which the present invention is applied.
The figure which shows the delay time characteristic of A communication system.

FIG. 8 is a diagram illustrating a DSA communication system to which the present invention is applied;
The figure which shows the time rate of the continuous transmission stop state when sharing the same frequency band with the communication system A.

FIG. 9 is a diagram illustrating an example of a frame configuration of a DSA communication system.

FIG. 10 is a diagram showing an operation outline of the CSMA communication system.

FIG. 11 is a block diagram showing a configuration example of a base station device of a conventional DSA communication system.

FIG. 12 is a block diagram showing a configuration example of a terminal device of a conventional DSA communication system.

FIG. 13 is a diagram showing an outline of operation when a conventional DSA communication system and a CSMA communication system share the same frequency band.

FIG. 14 is a diagram showing conventional delay time characteristics of a DSA communication system and a CSMA communication system.

FIG. 15 is a diagram illustrating a continuous transmission stop state time rate when the DSA communication system shares the same frequency band with the CSMA communication system.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 data input / output means 2 buffer 3 scheduler 4 timing management means 5 transmission control means 6 transmission means 7 reception means 8 reception control means 9 interference wave detection means 10 reservation signal generation means 11 Rch allocation control means 21 a to 21 f data transmission time 31 Data input / output means 32 buffer 33 scheduler 34 timing management means 35 transmission control means 36 transmission means 37 reception means 38 reception control means 39 interference wave detection means 41 data input / output means 42 buffer 43 timing management means 44 transmission control means 45 transmission means 46 Reception means 47 Reception control means 51a-51b Band usage time of DSA communication system 52a-52h Band usage time of CSMA communication system 61a-61c Band usage time of DSA communication system 62a-62g CSMA communication system Communication area allocated to the band use time 63a~63b reservation signal 71 a to 71 d DSA bandwidth utilization time of the communication system 72a to 72e CSMA bandwidth utilization time of the communication system 73a~73b random access burst (Rch)

Continued on the front page F-term (reference) 5K028 AA11 AA14 BB04 CC02 CC05 DD01 DD02 HH02 KK33 LL42 LL43 NN01 PP11 RR01 SS24 5K034 AA01 AA05 AA15 DD03 EE03 FF13 JJ11 LL02 LL04 LL06 NN13 NN11 AQ11 AQA11AQ11AQAQAQAQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ either Q or Q or Q? GG02 JJ02 JJ15 JJ16

Claims (7)

[Claims] 1. A base station apparatus comprising one or more terminal apparatuses, and the base station apparatus manages a frame cycle which is a basic cycle of communication, and performs burst allocation to each terminal apparatus at the beginning of the frame cycle. A base station apparatus of a DSA communication system that performs communication between the base station apparatus and each terminal apparatus; an interference wave detection unit that detects an interference wave received at a predetermined level or more; and manages transmission / reception timing based on the frame period. When the interference wave is not detected during a predetermined time from the beginning of the frame period, a communication right of the frame is acquired and a burst signal is transmitted and received based on the transmission and reception timing, and the burst signal is transmitted and received during the predetermined time. Transmission control means for stopping transmission and reception of a burst signal for one frame period when the interference wave is detected. In the base station device of the system, when the interference wave is not detected continuously for a predetermined time from a predetermined timing within a frame period in which the transmission of the burst signal is stopped to a frame end, the communication right is set in a next frame. A base station apparatus for a DSA communication system, comprising: a reservation signal generating unit that transmits a reservation signal for acquiring a reservation signal. 2. The base station apparatus of the DSA communication system according to claim 1, wherein the reservation signal generating unit is configured to, when a predetermined number of frames in which neither the burst signal nor the reservation signal can be transmitted continues, A base station apparatus for a DSA communication system, wherein detection of an interference wave is started at an earlier timing. 3. The DSA according to claim 1 or claim 2.
In the base station apparatus of the communication system, the transmission control unit transmits and receives the burst signal without detecting the interference wave at the beginning of the frame period in a frame next to the frame in which the reservation signal is transmitted. A base station apparatus of a DSA communication system having a configuration. 4. A base station apparatus comprising at least one terminal apparatus and a base station apparatus, wherein the base station apparatus manages a frame cycle which is a basic cycle of communication, and performs burst allocation to each terminal apparatus at the beginning of the frame cycle. A base station apparatus of a DSA communication system that performs communication between the base station apparatus and each terminal apparatus; an interference wave detection unit that detects an interference wave received at a predetermined level or more; and manages transmission / reception timing based on the frame period. When the interference wave is not detected during a predetermined time from the beginning of the frame period, a communication right of the frame is acquired and a burst signal is transmitted and received based on the transmission and reception timing, and the burst signal is transmitted and received during the predetermined time. Transmission control means for suspending transmission and reception of a burst signal for one frame period when the interference wave is detected; And information storage means for storing information becomes transmission canceled by the control, in the frame period, the random access as an area for data transmitted from the new terminals burst (R
and a random access burst allocating means for allocating channel (ch). If there is a frame for which transmission of the burst signal is stopped before a frame for which the communication right is acquired, the information storage means Random access burst allocation control means for using part or all of an area allocated to the random access burst (Rch) as a communication area between a base station apparatus and an existing terminal apparatus in accordance with the amount of stored information. A base station apparatus for a DSA communication system. 5. The base station apparatus of a DSA communication system according to claim 4, wherein said random access burst allocation control means is configured to: when the amount of information stored in said information storage means exceeds a predetermined value. A base station apparatus for a DSA communication system, wherein a whole area allocated to a random access burst (Rch) is used as the communication area, and a communication right for a subsequent frame is acquired. 6. The DSA according to claim 4 or claim 5.
In the base station apparatus of the communication system, the random access burst allocation control means may transmit the random access burst (Rch) over a plurality of frames for which the communication right has been acquired, as long as there is an amount of information stored in the information storage means. ), Wherein a part or all of an area allocated to the base station apparatus is used as the communication area. 7. The DSA according to claim 4 or claim 5.
In the base station device of the communication system, the random access burst allocation control means combines the amount of information stored in the information storage means with the amount of information stored in each terminal device notified from each terminal device, and performs random access burst allocation. A base station apparatus for a DSA communication system, wherein the base station apparatus has a configuration used for (Rch) allocation control.