JP2000217143A - Mobile communication system and channel allocation method for data of the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mobile communication system with which voice and data channel can be assigned, while keeping prescribed communication quality without causing rapid fluctuation in an interference amount due to fluctuation in traffic by dialing or end of call of a mobile station. SOLUTION: This mobile communication system is provided with a plurality of base stations and a plurality of mobile stations connected to the base stations via a radio channel. An accommodated channel number is decided to suppress traffic fluctuation in its own cell on the basis of past communication traffic, so as to assign voice and data to each channel in response to the accommodated channel number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for allocating voice and data channels in a mobile communication system to which DS-CDMA is applied, and more particularly to a plurality of base stations and mobile stations constituting a plurality of radio communication areas. The present invention relates to a channel allocation method in wireless communication between stations.

[0002]

2. Description of the Related Art A method of allocating channels for voice and data (hereinafter, referred to as data packets) in conventional wireless communication will be described. DS-CDMA (Direct
In a mobile communication system to which Sequence Code division multiple access is applied, a plurality of base stations form a communication area called a cell, and in that cell, a mobile station and a base station wirelessly generate a link, and perform communication. Do. In this mobile communication system, for example, radio signals (voice and data) transmitted from a plurality of mobile stations are transmitted to a base station.

The radio signals transmitted to these base stations are E
It is very important to keep b / I0 (the ratio of signal power to interference power per bit) at a constant level, and DS-CD
A mobile communication system to which the MA is applied is a system in which, for example, when data is transmitted with high power such that Eb / I0 of one mobile station is improved, the line quality of another mobile station is degraded. Therefore, in a mobile communication system to which DS-CDMA is applied, for example, transmission power control is performed by each mobile station in order to keep Eb / I0 of a radio signal transmitted to a base station constant.

FIG. 8 shows, for example, the document RCS97-10.
3 (The Institute of Electronics, Information and Communication Engineers THE INSTITUTE OF ELECTRONICS,
INFORMETION AND COMMUNICATION ENGINEERS;
TECHNOCAL REPORT OF IBICE SST97-64, RCS97 103 (1997
10 is a diagram schematically showing a conventional channel assignment method shown in FIG. 9; for example, a reservation packet (transmission data packet by mobile station number) for each mobile station shown in FIG. Assigned.

FIG. 8 shows the relationship between data packets transmitted from a plurality of base stations and the time axis. The conventional channel allocation method shown here is a communication system in which an immediate circuit switching system (voice communication) and a standby packet switching system are mixed. In particular, when transmitting a packet, It is assumed that reserved channel allocation is used. The numbers in each reservation packet in FIGS. 8 and 9 are individual numbers assigned to each mobile station.

As can be seen from the drawing, in the conventional channel allocation method for reserved packets, the base station grants a data packet transmission permission to each mobile station transmitting each reservation packet after a predetermined time, and receives this transmission permission. Each mobile station transmits a data packet as needed. However, at this time, if the number of accommodated channels exceeds a predetermined capacity limit determined by Eb / I0, the base station gives a delay instruction to the mobile station transmitting the reservation packet, and as shown in FIG. Limits the number of mobile stations transmitting data packets to the base station. Specifically, in FIG. 8, by giving a delay instruction to the fifth mobile station, the corresponding data packet is delayed as shown by the arrow.

[0007] With respect to traffic fluctuations occurring in a conventional mobile communication system, for example, due to a call or termination of a mobile station, the base station changes the transmission power to each mobile station each time. An instruction is transmitted, and transmission power control is performed in each mobile station. As described above, in the conventional channel assignment method in wireless communication, by controlling the transmission power of each mobile station and limiting the number of mobile stations transmitting packet data, voice and data can be maintained at a certain quality. That is, communication is performed such that Eb / I0 can be maintained at a constant level.

[0008]

SUMMARY OF THE INVENTION However,
Fluctuations in traffic that occur in a conventional mobile communication system may cause a sudden fluctuation in the amount of interference (such as fluctuations at time t8 in FIG. 8). Then, the base station transmits a transmission power change instruction to each mobile station so that the reception power from each mobile station becomes constant. In such a case,
In each mobile station, there is a limit to the amount of change in transmission power due to a single transmission power control instruction, so that there is a problem that the transmission power control cannot completely follow this rapid change in traffic.

Further, in the same case as described above, even when transmission power control is performed by each mobile station, there is a problem that, for example, line quality is deteriorated until transmission power control is completed. there were.

Further, in the conventional channel allocation method, when interference occurs due to an increase in traffic, the transmission power is increased by many mobile stations, and the power consumption is wasted. .

The present invention has been made in view of the above, and does not cause a sudden change in the amount of interference caused by a change in traffic caused by a call or termination of a mobile station.
An object of the present invention is to provide a mobile communication system capable of allocating voice and data channels so as to maintain constant communication quality, and a method of allocating data channels in the system.

[0012]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, in a mobile communication system according to the present invention, a plurality of base stations (corresponding to a base station 101 in an embodiment described later) are connected to these base stations via a radio line. A plurality of mobile stations (corresponding to the mobile stations 1 to 10), and determines the number of channels to be accommodated based on past communication traffic so as to suppress traffic fluctuations within the own cell, thereby enabling voice and data transmission. Is assigned to each channel according to the number of accommodated channels (see FIG. 1).

According to the present invention, channels are allocated based on the result of statistical processing of past communication traffic, for example, the average of the number of accommodated channels in the past, so that traffic fluctuations within the own cell can be suppressed to a low level. . As a result, traffic fluctuation does not occur unlike the conventional mobile communication system. In a conventional mobile communication system, for example, until transmission power control is completed,
Although the line quality is degraded, the mobile communication system of the present invention does not degrade the line quality because the traffic fluctuation is kept low. Further, in the mobile communication system according to the present invention, since the traffic fluctuation is suppressed low, the transmission power is not increased by many mobile stations, and the power consumption is wastefully consumed as in the related art. It doesn't happen.

[0014] In the channel allocation method according to the next invention, the number of channels to be accommodated is determined based on past communication traffic so as to suppress traffic fluctuations within the own cell, thereby allowing voice and data to be accommodated. Channel assignment steps to assign to each channel according to the number of channels (steps S1 to S8, steps S11 to S14, step S
21 to step S26).

According to the present invention, the channels are allocated based on the statistical processing result of the past communication traffic, for example, the average of the number of accommodated channels in the past, so that the traffic fluctuation in the own cell can be suppressed low. . As a result, traffic fluctuation does not occur as in the conventional channel allocation method. In addition, in the conventional channel allocation method, for example, the line quality is deteriorated until the transmission power control is completed. However, in the channel allocation method of the present invention, since the traffic fluctuation is suppressed low, the line quality is reduced. Does not deteriorate. Further, in the channel allocation method according to the present invention, since the traffic fluctuation is suppressed low, the transmission power is not increased by many mobile stations, and the power consumption is wastefully consumed as in the related art. It doesn't happen.

In the channel allocating method according to the next invention, the channel allocating step determines the number of channels to be accommodated from past circuit-switched traffic and packet traffic, which are the communication traffic, and further allocates more channels than the number of channels. In the case where a request is generated, a delay step (corresponding to steps S3 to S5 of an embodiment described later) for holding a certain number of channels by delaying the packet is included.

According to the present invention, the required number of channels is determined from the past circuit-switched traffic and packet traffic. Therefore, when a channel allocation request exceeding the number of accommodated channels occurs, that is, a reservation packet is transmitted from the mobile station. In this case, the number of channels and communication traffic can be kept constant by waiting for a transmission data packet corresponding to the reservation packet.

In the channel allocation method according to the next invention, the channel allocation step is a step of increasing the number of channels to be allocated when the packet exceeds a predetermined delay amount when the number of channels is kept constant. (Corresponding to step S11, step S13, and step S14 of the embodiment described later).

According to the present invention, when a channel allocation request equal to or more than the number of accommodated channels occurs, that is, when a reservation packet is transmitted from a mobile station, a transmission data packet corresponding to the reservation packet is made to wait, and , The number of accommodated channels, the average number of channels in the past,
Predetermined number: It is the value of the sum of N (arbitrary constant determined by the system). At this time, the predetermined number: N may be the number of channels accommodated before the transmission data packet corresponding to the newly arrived reservation packet is allocated, or the number of channels allocated to the transmission data packet may not exceed a certain rate of change. You may decide. As a result, it is possible to perform channel allocation while keeping the traffic fluctuation low.

[0020] In the channel assignment method according to the next invention, the channel assignment step is based on the number of accommodated channels determined from the data length of the packet and the past circuit-switched traffic or packet traffic, which is the communication traffic. , Assigning voice and data to each channel according to the number of accommodated channels,
At the end of data communication, voice and data channels are allocated so that abrupt changes in the number of channels or traffic do not occur (corresponding to step S7 in an embodiment described later).

According to the present invention, since the channel is allocated based on the data length of the packet, a decrease in the number of channels due to the end of the data communication can be suppressed, thereby preventing a rapid change in traffic. .

[0022] In the channel assignment method according to the next invention, the channel assignment step is based on the data length of the packet to be assigned to the channel and the data length of the packet already assigned to the channel. By performing channel assignment, a sudden change in the number of channels that occurs at the end of data communication is suppressed (corresponding to step S7 in an embodiment described later).

According to the present invention, the last slot of the data length of the packet to be allocated to the channel and the last slot of the data length of the packet already allocated to the channel can be directly confirmed. Since the channels are allocated according to the above, the decrease in the number of channels due to the end of the data communication can be minimized. As a result, a sudden change in traffic can be more strongly prevented.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a mobile communication system according to the present invention and a data channel allocation method in the system will be described below in detail with reference to the drawings. The present invention is not limited by the embodiment.

FIG. 1 shows a result of channel allocation for voice and data (hereinafter referred to as a transmission data packet) by a mobile communication system for realizing the channel allocation method according to the present invention. Note that this channel assignment result is obtained, for example, as shown in FIG. 2 by a base station 101 constituting a communication area and each mobile station (1, 2, 3, 3).
4, 5, 6, 7, 8, 9, 10).

Hereinafter, the channel assignment method according to the present invention will be specifically described. First, FIG. 3 shows a state in which reservation packets from a plurality of mobile stations as shown in FIG. 2 have randomly arrived at the base station. For example, each of these reservation packets is shown based on a time axis. It is a thing.
FIG. 4 schematically shows the packet length of each transmission data packet included as information in the reservation packet shown in FIG.

When these reservation packets are transmitted through a random access channel, for example,
As illustrated (corresponding to times t0 and t7), a plurality of reservation packets may arrive at the base station at the same time. The number of the reservation packet in FIG. 2 represents the type of each mobile station (corresponding to mobile station 1 to mobile station 10 shown in FIG. 2).
Also, in the present embodiment, the channel is DS-S
2 shows a channel realized by a spreading code in the DMA system. Further, each mobile station does not necessarily need to transmit the reservation packet in slot units, and may transmit the reservation packet to the base station using a channel other than the random access channel.

FIG. 5 shows a flowchart of a specific channel allocation method executed in the mobile communication system of the present invention. In the channel assignment method according to the present invention, in a communication system in which an immediate circuit switching system (voice communication) and a standby packet switching system are mixed, in particular, the reservation assignment of a packet channel is used. As shown in FIG. 1, two voice communications have already been allocated using the circuit switching method, and before time t1, data packets x1 and x2 to which channels have been allocated have been allocated. It is assumed that the average number of accommodated channels in the past is four.

For example, at time t0 shown in FIG.
Number of reserved packets reserved: RSVbuf is 1 or more, or number of newly reserved packets from each mobile station: R
When the value of SVnew is 1 or more (step S1, Y
es) updates the packet priority table of the base station by giving a priority to the reserved packet held before time t0 (step S2). At this time, the number of reserved packets held before time t0: RSVbuf
Is 0, the reservation packet transmitted from the mobile station at time t0 has the highest priority.

On the other hand, before time t0, the number of reserved packets held: RSVbuf and the number of newly arrived packets: RS
When both values of Vnew are 0 (Step S1, No)
Does not perform channel assignment for transmission data packets (end). However, the base station, based on the packet length information of the transmission data included in the reservation packet transmitted by the mobile station,
Each reservation packet may be weighted, and a packet priority table may be created based on the weighted reservation packet. The priority of the reservation packet may be determined by a preset mobile station number (for example, corresponding to 1 to 10 in FIG. 3) or, for example, a priority number included in the reservation packet. Alternatively, it may be determined so that the variation in the number of accommodated channels at the end of the call is minimized.

Next, in the base station, the number of accommodated channels composed of transmission data packets and circuit-switched voice: AS
Update Sch (step S3). Here, a method of updating the number of accommodated channels: ASSch will be described in detail with reference to FIG.

For example, the average traffic in the past, that is, the average number of accommodated channels before the time T from the time of channel allocation: TRAFave (here, previously defined as 4), the number of newly arrived packets: RSVnew, and the next Number of channels already allocated in the slot:
RSVold and the number of reserved reserved packets: RSV
buf (Step S11, Ye
s), number of accommodated channels: The value of ASSch is TRAFa
The value of ve is substituted as it is (step S12). If TRAFave does not become an integer in the average before the time T from the time of channel allocation, a value obtained by truncating the decimal part or an integer greater than the average number of channels and closest to the average number of channels may be used as TRAFave.

On the other hand, TRAFave is set to RSVnew and RVnew.
If the value of the transmission permission delay value of the transmission data packet corresponding to the reservation packet: Tbuf is equal to or less than the maximum transmission permission of the transmission data packet corresponding to the reservation reservation packet, when the value is smaller than the sum of SVold and RSVbuf (step S11, No) Delay time: Either less than DLYmax or the product of TRAFave and Tbuf is the total number of transmission request data packets of all new reservation packets:
When Pnew is smaller than the sum of the total number of transmission request data packets of the reservation reservation packet: Pbuf (step S1)
3, Yes), the number of accommodated channels: the value of ASSch is T
The value of the sum of RAFave and a predetermined number: N (arbitrary constant determined by the system) is substituted (step S14).

When TRAFave is smaller than the sum of RSVnew, RSVold, and RSVbuf (step S11, No), the value of Tbuf is DLYm.
If the product of TRAFave and Tbuf is larger than the sum of Pnew and Pbuf (step S13, No), the value of the number of accommodated channels: ASSch is substituted with the value of TRAFave as it is (step S12).

The predetermined number: N may be the number of channels accommodated before the transmission data packet corresponding to the newly reserved packet is allocated, or the number of channels allocated to the transmission data packet may exceed a certain rate of change. You may decide not to. When N is determined so that the number of channels allocated to transmission data packets does not exceed a certain rate of change, for example, the rate of change may be set to 10%, or the variation in the amount of interference may be 1 dB. The value may be within the range, or ASSch and R
It may be a difference from SVold.

Thus, the number of accommodated channels: ASSch
Is updated (step S3), the base station further compares the updated ASSch with RSVold (step S3).
4) In the case where RSVold is less than ASSch (Step S4, No), channel assignment of a transmission data packet corresponding to the reservation packet is performed, and when channel assignment is possible (Step S6, Yes), the corresponding mobile station is assigned. Send a packet transmission instruction to
7) Update the packet priority table again (step S2). If the channel cannot be allocated (step S6, No), the process ends without performing the channel allocation.

On the other hand, in the comparison in step S4, when RSVold is equal to or larger than ASSch (step S4, Yes), a standby instruction is issued to the mobile station corresponding to the reservation packet (step S5).

Here, the channel assignment method in step S6 will be described in detail with reference to FIG. First,
For example, a reserved packet having the highest priority is selected from the packet priority table updated in advance (step S21). Then, the number of fluctuations of the accommodated channel due to the allocation of the selected reservation packet is obtained, and the number of fluctuations of the accommodated channel is compared with a predetermined allowable number C of accommodated channels (step S22). If the number is equal to or less than C (step S2
(2, Yes) allocates the channel of the transmission data packet corresponding to the selected reservation packet (step S2).
3). In the comparison in step S22, when the delay amount of the reserved packet having the highest priority: DLYmax exceeds the preset reserved packet maximum delay permission amount: DLYlim (step S22, YES), the reserved packet having the highest priority is also set. (Step S23).

On the other hand, in the comparison in step S22, when the accommodated channel fluctuation number is larger than C (step S22).
(22, No) selects the next higher priority reserved packet from the packet priority table updated in advance (step S24). Then, the predetermined number: L is compared with the number of reserved packets from the highest priority to the reselectable reserved packet, which is determined in advance to be reselected (step S25), and the number of reselectable reserved packets is determined. Is less than or equal to L (Yes in step S25), the number of accommodated channel fluctuations due to the allocation of the reselected reserved packet is determined, and the accommodated channel fluctuation rate and C are compared again (step S22). Note that the value of C may be a fixed value set in advance. Alternatively, it may be a value obtained from a ratio corresponding to the number of accommodated channels. Further, the number of accommodated channel fluctuations may include not only the fluctuation caused by allocating the reservation packet, but also the accommodated channel fluctuation accompanying the end of communication of the already accommodated channel.

In the comparison in step S25, if the number of reselected reserved packets is larger than L, or if there is no reserved packet to select (step S25, No)
Does not perform channel assignment (step S26).

Next, the case where a transmission data packet (see FIG. 4) corresponding to the reservation packet of FIG. 3 is actually allocated will be described according to the channel allocation methods of FIGS. 5, 6 and 7. Here, the value of T is set to 2 packet slot lengths. For example, when the average number of channels is not divisible, an integer smaller than the average number of channels and closest to the average number of channels is set to TRAFave, and the value of Tbuf is set to 2, The past value of TRAFave is 4, the allowable accommodation channel fluctuation rate C is 1, the number L of reselectable reserved packets is 1, the maximum permitted delay amount of reserved packets: DL
Assuming that Ylim is 5 packet lengths and the predetermined number: N is 1, the channel assignment operation when the reservation packet of FIG. 2 arrives at the base station will be described.

When the base station receives the reservation packet,
After a certain delay, the base station issues a packet transmission instruction (step S8 in FIG. 5) and a standby instruction (step S5 in FIG. 5). Further, the mobile station receives the packet transmission instruction and the standby instruction and receives a certain delay. The transmission of the transmission data packet will be performed later. Here, the transmission delay time of the mobile station and the base station is, for example, one packet slot length.

Accordingly, in response to the reservation packet transmitted by the mobile station, the base station gives a packet transmission instruction after one packet slot length, and the mobile station also transmits a transmission data packet after one packet slot length. Will be performed. In the present embodiment, even when the standby instruction is not issued, the standby instruction may be issued by not issuing an instruction from the base station to the mobile station. Further, the transmission delay time of the mobile station and the base station may be longer than one packet slot length, but is not limited thereto.

First, at time t1 shown in FIG. 3, there is no reserved packet held before time t0, and TRA
Fave is 4, RSVold is 2, RSV
Since new is 2 (reserved packet (1), reserved packet (2)) and RSVbuf is 0 (step S11, Yes), the number of accommodated channels: ASSch is
4. Therefore, here, the base station operates at time t in FIG.
In step 2, channel allocation is performed for the transmission data packet (1) and the transmission data packet (2), and a packet transmission instruction is issued to the mobile station that transmitted the reservation packet (1) and the reservation packet (2).

Next, at time t2 shown in FIG.
TRAFave is 4, RSVold is 4,
RSVnew is 1 (reservation packet (3)) and RSVnew
Vbuf is 0 (Step S11, No), DLYmax is 0, and TRAFave (= 4)
And Tbuf (= 3) are 12 and Pnew is 5
And Pbuf is 0 (step S13, N
o), number of accommodated channels: ASSch becomes 4, and the base station issues a hold instruction to the mobile station that transmitted the reservation packet (3).

Next, at time t3 shown in FIG.
TRAFave is 4, RSVold is 4,
RSVnew is 1 (reservation packet (4)) and RSVnew
Vbuf is 1 (reserved packet (3)) (step S11, No), DLYmax is 1 (reserved packet (3)), TRAFave (= 4) and Tbu
The product with f (= 3) is 12, Pnew is 4,
Since Pbuf is 5 (step S13, No), the number of accommodated channels: ASSch is 4, and the base station
The mobile station that has transmitted the reservation packet (4) issues a hold instruction.

Next, at time t4 shown in FIG.
TRAFave is 4, RSVold is 4,
RSVnew is 0 and RSVbuf is 2 (reserved packet (3), reserved packet (4)) (step S
11, No), DLYmax is 2 (reserved packet (3)), and TRAFave (= 4) and Tbuf
(= 3) is 12, Pnew is 0, and P
Since buf is 9 (step S13, No), the number of accommodated channels: ASSch is 4, and the base station gives no instruction.

Next, at time t5 shown in FIG.
TRAFave is 4, RSVold is 3 because data packet (1) ends, and RSVnew is 1
(Reservation packet (5)), RSVbuf is 2 (reservation packet (3), reservation packet (4)) (step S11, No), and DLYmax is 3 (reservation packet (3)). TRAFave (= 4) and T
Since the product with buf (= 3) is 12, Pnew is 3, and Pbuf is 9 (step S13, Ye
s), number of accommodated channels: ASSch is 5. Therefore, at time t6 in FIG. 1, for example, the base station allocates a channel to the transmission data packet (3) corresponding to the reservation packet (3), which is the reservation packet with the highest priority in the priority table. , Reservation packet (3)
A packet transmission instruction is issued to the mobile station that has transmitted the packet.

For the transmission data packet corresponding to the reservation packet (4), which is the next highest priority reservation packet, TRAFave is 4, and RSVol is
d is 4, RSVnew is 0, RSVbuf
Is 2 (reserved packet (4), reserved packet (5)) (step S11, No), DLYmax is 2 (reserved packet (4)), and TRAFave (=
4) and the product of Tbuf (= 3) is 12 and Pnew
Is 0 and Pbuf is 7 (step S1).
3, No), the number of accommodated channels: ASSch is 4, and the base station gives no instruction. That is, no new channel is allocated.

Next, at time t6 shown in FIG.
TRAFave is 4, RSVold is 4,
RSVnew is 0 and RSVbuf is 2 (reservation packet (4), reservation packet (5)) (step S
11, No), DLYmax is 3 (reserved packet (4)), and TRAFave (= 4) and Tbuf
(= 3) is 12, Pnew is 0, and P
Since buf is 7 (step S13, Yes), the number of accommodated channels: ASSch is 5.

At this time, in the base station, if the priority is determined in the order of arrival of the reservation packet, the reservation packet (4) has a higher priority than the reservation packet (5), but if the reservation packet (4) is selected, Since the communication end time of the data packet (3) for which channel assignment has been completed and the communication end time of the data packet (4) are the same, priority is given to the reserved packet (5) with a smaller change in the number of accommodated channels. select. Therefore, at the base station, at time t7 in FIG.
For example, a channel is allocated to a transmission data packet (5) corresponding to the reservation packet (5), which is a reservation packet with a smaller change in the number of accommodated channels, and further to the mobile station that transmitted the reservation packet (5). Instructs packet transmission.

Next, at time t7 shown in FIG.
Since TRAFave is 4, RSVold becomes 3 with the end of one voice communication, and RSVnew is 0 (Step S11, Yes), the number of accommodated channels: AS
Sch is 4. Therefore, at time t8 in FIG. 1, for example, the base station allocates a channel to a transmission data packet (4) corresponding to the reservation packet (4), which is the reservation packet with the highest priority in the priority table, and Then, the mobile station that has transmitted the reservation packet (4) is instructed to transmit a packet.

Next, at time t8 shown in FIG.
TRAFave is 4, RSVold is 4,
RSVnew is 3, RSVbuf is 0 (Step S11, No), DLYmax is 0, the product of TRAFave (= 4) and Tbuf (= 3) is 12, and Pnew is 10. , Pbuf is 0 (Step S13, No), the number of accommodated channels:
ASSch becomes 4, and the base station gives no instruction. That is, no new channel is allocated.

Next, at time t9 shown in FIG.
TRAFave is 4, RSVold becomes 3 with the end of communication of data packet 5, RSVnew is 0, and RSVbuf is 3 (reservation packet (6), reservation packet (7), reservation packet (8)) ( (Step S11, No), DLYmax is 1, and T
The product of RAFave (= 4) and Tbuf (= 3) is 12
Since Pnew is 0 and Pbuf is 10 (No at Step S13), the number of accommodated channels: ASS
ch is 4. Therefore, at the base station, time t in FIG.
For example, a channel is allocated to the transmission data packet (6) corresponding to the reservation packet (6), which is the reservation packet with the highest priority in the priority table, and the mobile station transmits the reservation packet (6). Instructs the station to transmit packets.

Next, at time t10 shown in FIG. 3, TRAFave is 4, and data packet (3)
With the end of communication, RSVold becomes 3, and RSVne
w is 0, and RSVbuf is 2 (reservation packet (7), reservation packet (8)) (step S1).
1, No), DLYmax is 2, and TRA
Since the product of Fav (= 4) and Tbuf (= 3) is 12, Pnew is 0, and Pbuf is 10 (Step S13, No), the number of accommodated channels: ASSc
h becomes 4. Therefore, at the base station, time t1 in FIG.
For example, a channel is allocated to a transmission data packet (7) corresponding to the reservation packet (7), which is the reservation packet having the highest priority in the priority table, and the mobile station transmits the reservation packet (7). Instructs the station to transmit packets.

Next, at time t11 shown in FIG. 3, TRAFave is 4, and data packet (4)
With the end of the communication, RSVold becomes 3, and RSVne
w is 1 (reserved packet (9)) and RSVbuf is 1 (reserved packet (8)) (step S11, N
o) Further, since DLYmax is 3 (Step S13, Yes), the number of accommodated channels: ASSch is 5
Becomes

At this time, when the base station determines the priority in the order of arrival of the reservation packet, the reservation packet (8) has a higher priority than the reservation packet (9). Since the communication end time of the data packet (6) for which channel assignment has been completed and the communication end time of the data packet (8) are the same, priority is given to the reservation packet (9) with a smaller change in the number of accommodated channels. select. Therefore, at the base station, at time t12 in FIG.
In addition, for example, a channel is allocated to a transmission data packet (9) corresponding to the reservation packet (9), which is a reservation packet with a smaller variation in the number of accommodated channels, and further to the mobile station that transmitted the reservation packet (9). Then, it issues a packet transmission instruction.

After updating the packet priority table, the base station updates the ASSch again. At this time, T
RAFave is 4, and RSVo is associated with the end of communication of data packet (4) and allocation of data packet (9).
ld becomes 4, RSVnew is 0, and RSVbu
f is 1 (reserved packet (8)) (step S1)
1, No), and because DLYmax is 4 (step S13, Yes), the number of accommodated channels: ASSch
Is 5, but the reserved packet (8) does not satisfy the number of accommodated channel fluctuations, and further, there is no reserved packet to be allocated, so that channel allocation is not performed.

Next, at time t12 shown in FIG. 3, TRAFave is 4, and data packet (9)
With the end of communication, RSVold becomes 3, and RSVne
Since w is 0, RSVbuf is 1 (reserved packet (8)), and DLYmax is 4 (step S11, Yes), the number of accommodated channels: ASSch is
It becomes 4. However, when the base station selects the reservation packet (8), the communication end time of the data packet (7) and the communication end time of the data packet (8) for which channel assignment has already been completed are the same. No channel assignment for packet (8) is performed.

Finally, at time t13 shown in FIG. 3, TRAFave is 3, RSVold becomes 2 with the end of communication of data packet (6) and data packet (7), and RSVnew becomes 1 (reserved packet ( 10)), RSVbuf is 1 (reserved packet (8)), and DLYmax is 5 (step S11, Yes), so the number of accommodated channels: ASSch
Becomes 4. However, when the base station selects the reservation packet (8), the number of accommodated channel fluctuations becomes two. Therefore, the base station selects the reservation packet (10) having the next highest priority, and at time t14 in FIG. Channel assignment of the transmission data packet (10) corresponding to (10) is performed, and further, a packet transmission instruction is issued to the mobile station that transmitted the reservation packet (10).

After updating the packet priority table, the base station updates ASSch again. At this time, T
RAFave is 3, and RSVo is associated with the end of communication of data packet (6) and allocation of data packet (10).
ld becomes 3, RSVnew is 0, and RSVbu
f is 1 (reserved packet (8)) (step S1)
1, No), and since DLYmax is 6, the number of accommodated channels: ASSch is 4, but the reserved packet (8) exceeds DLYlim, so that channel allocation is performed regardless of the number of accommodated packet fluctuations. And
A packet transmission instruction is issued to the mobile station that has transmitted the reservation packet (8).

In the present embodiment, the case where voice and transmission data packets coexist has been described. However, the operation does not change even when only transmission data packets are used. Similarly, the operation does not change even when transmission data packets and voice packets coexist. In the case where transmission data packets and voice packets coexist, the maximum allowable delay amount for transmission data packets and the maximum allowable delay amount for voice packets may be set separately.

As described above, in the channel assignment method according to the present invention, unlike the related art, a sudden change in the amount of interference caused by a change in traffic due to a call or termination of a mobile station does not occur. For example, channel assignment of voice and transmission data packets can be performed so as to maintain a certain communication quality.

[0064]

As described above, according to the present invention, according to the present invention, a channel is allocated based on the statistical processing result of past communication traffic, for example, based on the average of the number of accommodated channels in the past. Traffic fluctuations can be kept low. As a result, there is an effect that the traffic does not fluctuate unlike the conventional mobile communication system. In a conventional mobile communication system,
Until the transmission power control is completed, the line quality is degraded. However, the mobile communication system of the present invention has an effect that the line quality does not degrade because the traffic fluctuation is kept low. Further, in the mobile communication system according to the present invention, since the traffic fluctuation is suppressed low, the transmission power is not increased by many mobile stations, and the power consumption is wastefully consumed as in the related art. This has the effect of not being lost.

According to the next invention, a channel is allocated based on the statistical processing result of past communication traffic, for example, the average of the number of accommodated channels in the past, so that traffic fluctuation in the own cell can be suppressed to a low level. it can. As a result, there is an effect that the traffic does not fluctuate as occurs in the conventional channel allocation method. In addition, in the conventional channel allocation method, for example, the line quality is deteriorated until the transmission power control is completed. However, in the channel allocation method of the present invention, since the traffic fluctuation is suppressed low, the line quality is reduced. Does not deteriorate. Further, in the channel allocation method according to the present invention, since the traffic fluctuation is suppressed low, the transmission power is not increased by many mobile stations, and the power consumption is wastefully consumed as in the related art. This has the effect of not being lost.

According to the next invention, the required number of channels is determined from the past circuit-switched traffic and packet traffic. Therefore, when a channel allocation request exceeding the number of accommodated channels occurs, that is, when the reservation packet is transmitted from the mobile station, In the case of transmission, the transmission data packet corresponding to the reserved packet is made to stand by, so that the number of channels and communication traffic can be kept constant.

According to the next invention, when a channel allocation request equal to or larger than the number of accommodated channels occurs, that is, when a reservation packet is transmitted from a mobile station, a transmission data packet corresponding to the reservation packet is made to wait. Furthermore, the value of the number of accommodated channels is calculated by comparing the average number of channels in the past with
Predetermined number: It is the value of the sum of N (arbitrary constant determined by the system). At this time, the predetermined number: N may be the number of channels accommodated before the transmission data packet corresponding to the newly arrived reservation packet is allocated, or the number of channels allocated to the transmission data packet may not exceed a certain rate of change. You may decide. As a result, there is an effect that channel allocation can be performed while keeping the traffic fluctuation low.

According to the next invention, the channel allocation is performed based on the data length of the packet, so that a decrease in the number of channels due to the end of data communication can be suppressed.
As a result, there is an effect that a rapid change in traffic can be prevented.

According to the next invention, the last slot of the data length of the packet to be allocated to the channel and the last slot of the data length of the packet already allocated to the channel can be directly confirmed. , The decrease in the number of channels due to the end of data communication can be minimized. As a result, there is an effect that a sudden change in traffic can be more strongly prevented.

Therefore, according to the present invention, voice communication is performed so as to maintain a constant communication quality without causing a sudden change in the amount of interference caused by a change in traffic due to a call or termination of a mobile station. And a mobile communication system for allocating data channels.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a result of voice and data channel allocation by a mobile communication system that implements a channel allocation method according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a mobile communication system.

FIG. 3 is a diagram showing a state in which reservation packets from a plurality of mobile stations have randomly arrived at a base station.

FIG. 4 is a diagram schematically showing the packet length of each transmission data packet included as information in a reservation packet.

FIG. 5 is a flowchart showing a specific channel allocation method executed in the mobile communication system of the present invention.

FIG. 6 is a flowchart illustrating a method of updating the number of accommodated channels: ASSch.

FIG. 7 is a flowchart showing a specific channel assignment method.

FIG. 8 is a diagram showing a result of voice and data channel allocation by the conventional mobile communication system.

FIG. 9 is a diagram schematically illustrating the packet length of each transmission data packet included as information in a reservation packet.

[Explanation of symbols]

101 base stations, 1, 2, 3, 4, 5, 6, 7, 8,
9,10 Mobile station.

Claims (6)

[Claims] 1. A mobile communication system comprising a plurality of base stations and a plurality of mobile stations connected to these base stations via radio lines, comprising: A mobile communication system characterized by allocating voice and data to each channel according to the number of accommodated channels by determining the number of accommodated channels so as to suppress traffic fluctuation. 2. A method for allocating voice and data channels in a mobile communication system comprising a plurality of base stations and a plurality of mobile stations connected to these base stations via radio lines, comprising: A channel allocation step of allocating voice and data to each channel according to the number of accommodated channels by determining the number of accommodated channels so as to suppress traffic fluctuation in the own cell based on A method for allocating voice and data channels in a mobile communication system. 3. The channel allocating step determines the number of channels to be accommodated from past circuit-switched traffic and packet traffic, which are the communication traffic. 3. The voice and data channel allocation method in a mobile communication system according to claim 2, further comprising: a delay step of maintaining a constant number of channels by delaying the number of channels. 4. The method according to claim 1, wherein the step of allocating the channel includes a step of increasing the number of channels to be allocated when the packet exceeds a predetermined delay amount when the number of channels is kept constant. Item 4. A method for allocating voice and data channels in the mobile communication system according to Item 3. 5. The channel allocating step includes: transmitting voice and data based on a data length of a packet and the number of accommodated channels determined from the past circuit-switched traffic and packet traffic as the communication traffic.
Channels are allocated to each channel according to the number of accommodated channels, and further, voice and data channels are allocated at the end of data communication so that a sudden change in the number of channels or traffic does not occur. 4
The voice and data channel allocation method in the mobile communication system according to any one of the above. 6. The channel allocating step includes: a data length of a packet for which a channel is to be allocated;
3. A sudden change in the number of channels that occurs at the end of data communication is suppressed by allocating voice and data channels based on the data length of packets already allocated to channels. 5
The voice and data channel allocation method in the mobile communication system according to any one of the above.