JP2000032530A - Digital mobile communication random access control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the transmission of a mobile station resident remotely from a base station from being disturbed by continuous transmission of a signal from a mobile station which is located in the vicinity in a mobile communication system. SOLUTION: Mobile stations MS-A to MS-D access an access enable slot in a timing chart 401 and the MS-A resident in the vicinity is successful, then a base station informs the mobile stations of disable access other than the MS-A, and in the case of the end of transmission by the MS-A and even when signals to be sent next are present, access is awaited in reception by access enable 404 immediately after that and the other mobile station can access the frame. The access of all the MS-A to MS-D is successful and the transmission of the final MS-D is finished, when access enable slots 411, 412 are received continuously, all of the MS-A to MS-D become access transmission available.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air line control type access control method for notifying random mobile stations of access availability information in a digital mobile communication system in which a plurality of mobile stations share a framed radio channel. Things.

[0002]

2. Description of the Related Art As a typical example of this kind, there is a digital car telephone system standard (RCR STD27F revised: Radio Industries Association) currently provided in Japan.
In this RCR STD27, a random access method of the airline control system with partial echo (ICMA-PE) is standardized. In this case, the mobile station transmits a signal when transmitting a plurality of signals continuously. After the completion, when the access permission information becomes available, the next signal is transmitted.

When a plurality of mobile stations perform random access in mobile communication, a signal having a strong radio wave reaching the base station can be received. Therefore, a signal of a mobile station existing near the base station is received. There is a high probability feature. In such a situation, when one mobile station continuously transmits a plurality of signals, a mobile station that has successfully transmitted by random access has a high probability of succeeding in the next random access. However, in the method in which the random access of the next signal is immediately performed, there is a risk that a mobile station near the base station occupies the radio channel and the signal transmission of other mobile stations is hindered.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to prevent a mobile station located far from a base station from being hindered by continuous signal transmission of a mobile station located near the base station in a mobile communication system. It is to realize a mobile communication random access method that can perform the method.

[0005]

According to the present invention, when a mobile station transmits a signal and then transmits a next signal, the waiting time until the access permission / rejection information is notified at least twice consecutively is transmitted. Is provided. According to this configuration, there is an opportunity for another mobile station to transmit a signal during the waiting time.

[0006]

Embodiments of the present invention will be described below.
FIG. 1A shows a functional configuration of a mobile station to which an embodiment of the present invention is applied. The radio unit 101 performs modulation / demodulation / code decoding of transmission / reception signals of the mobile station, and the notification information analysis unit 102 analyzes the access availability information notified from the base station and notifies the base unit when transmitting the head unit. Analyze the information identifying the mobile station. Here, the information for specifying the mobile station includes an error detection code (CRC code) of a unit used in the above-mentioned RCR STD27 standard.
However, it can also be realized by using the machine number of the mobile station. The signal dividing means 103 divides a signal to be transmitted for each unit.
As adopted in the aforementioned RCR STD27 standard, whether or not the unit is the head unit of the divided signal, whether or not it is the last unit, and how many units remain after the unit The embodiment of the present invention can be realized by adding the unit division information indicating whether or not there is a difference. As shown in FIG. 2, the transmission signal (FIG. 2A) at the mobile station is divided into a plurality of units US, for example, as shown in FIG. 2B, and the head of each unit US has unit division information UH followed by transmission information. A main body UB is provided. As shown in FIG. 2C, the contents of the unit division information UH include a bit SB indicating whether the unit US is the first unit, a bit EB indicating whether the unit US is the last unit, and a bit EB indicating whether the unit US is the last unit. Followed by a continuation number UN indicating the number of units US. Each unit US not shown
Is provided with a CRC code. The number of units to be divided is determined by the length of the transmission signal.

When there is a transmission signal, transmission control means 104 in FIG. 1A controls transmission of units based on the notification result of access permission / inhibition of notification information analysis means 102 and mobile station identification information. Sent via 101. Further, when transmitting the first signal in succession, the transmission control means 104 immediately transmits the head unit when the access permission / inhibition information receives "permitted" once, but transmits the subsequent signals after the completion of the first signal transmission. In this case, in this embodiment, control is performed so that transmission is waited until the access permission / inhibition information is notified twice in succession.

FIG. 1B shows a functional configuration of a base station to which an embodiment of the present invention is applied. The radio unit 201 performs modulation / demodulation / encoding / decoding of a transmission / reception signal of the base station, the unit analysis unit 202 analyzes a signal from a unit received from the mobile station, and when the received unit is a head unit of the signal, Information for identifying the mobile station is extracted from the received unit. Further, the unit analysis means 202 determines whether or not the next frame is to be continued based on the unit continuation number information UN received from the mobile station. Received signal assembling means 2
Reference numeral 03 combines the received units US to assemble an original transmission signal and transmits it to the signal processing unit. In this embodiment, the assembling of the received signal and the processing of the assembled signal are not essential, and a detailed description thereof will be omitted. The notifying unit 204 generates information for notifying the mobile station of the mobile station and information of access permission / prohibition information based on the analysis result of the analyzing unit 202, and the information is transmitted via the wireless unit 201.

FIG. 3 shows a transmission process of the base station and the mobile station in the embodiment of the present invention. In this example,
A radio channel having a three-slot TDMA configuration, which is also adopted in the above-mentioned RCR STD27 standard, will be described as an example. R
According to the CR STD27 standard, after the transmission from the base station, the transmission and reception timings of the mobile station are not the same.
The configuration is such that the mobile station transmits after a certain period of time, and random access control is performed for every three slots constituting a radio frame. In this embodiment, four mobile stations MS-A, MS-B, MS-C, and MS-D in slot 3
The operation of the mobile station and the base station will be described by taking as an example the case where the mobile station performs random access. In FIG. 3, the base station has not received a signal from any mobile station before the slot timing 401 in FIG. 3A, and transmits the access permission information as the access permission as shown in FIG. 3B at the timing 401. ing. Mobile stations MS-A, MS-B,
Although MS-C and MS-D transmit the first unit based on the access permission / non-permission information 401, the base station cannot receive a plurality of signals at the same time, and receives only signals from mobile stations with strong radio waves. Will be. Here, MS-
Assuming that the radio wave to the base station is strong in the order of A, MS-B, MS-C and MS-D, the signal of the mobile station MS-A is received. Naturally, if the radio wave intensities of a plurality of mobile stations are almost the same, there may be cases where the signals interfere with each other and neither signal can be received normally. However, in this embodiment, for the sake of simplicity of explanation, The operation in the case where any signal is always received will be described. In the base station that has received the head unit of the mobile station MS-A, the mobile station M
Information for specifying the SA (FIG. 4C) and information for inhibiting access by other mobile stations are transmitted. Since it is known that the signal of the mobile station MS-A has been normally received, the mobile station MS-A transmits the continuation unit as shown in FIG.
B, MS-C, and MS-D wait for transmission until the access permission information is permitted.

In the base station, the transmission permission / inhibition information is enabled at the next transmission timing 404 after receiving the last unit from the mobile station MS-A, and the mobile stations MS-B, MS-C and MS-C.
D receives the information and performs random access again, but the mobile station MS-A waits for access. In this embodiment, since the mobile station MS-B has a stronger radio wave than the other two mobile stations as described above, transmission is continued through the same process as the above-described mobile station MS-A, and then the mobile station MS-B is transmitted. C, MS-D
Is transmitted sequentially. At the next timing 411 after the transmission of the mobile station MS-D is completed, the base station transmits the access permission information as “permitted”, but the mobile stations MS-A, MS-B, and MS-C.
Since MS and MS-D are all in the transmission standby state, no access from any mobile station occurs at this timing.
Accordingly, the base station transmits the access permission / prohibition information again as permitted at the next timing 412.
Since A, MS-B, MS-C and MS-D receive the access permission / inhibition information twice consecutively,
The random access is started all at once, and the signal is transmitted in the order of the mobile stations MS-A, MS-B, MS-C and MS-D through the same process as described above.

That is, the mobile station performs the processing shown in FIG.
First, the end flag is reset, that is, initialized to OFF (S
1) Waiting for the reception of the access permission in the access permission information (S)
2) Upon receiving this, it is checked whether the end flag is ON (S3). If the end flag is not ON, that is, OFF, it is checked whether there is a signal to be transmitted (S4). Returning to S2, if there is a transmission signal in step S4, the access unit is transmitted (S5),
If the access is successful (S6), it is checked whether the signal has ended (S7). If the signal has not ended, the continuation unit is transmitted and the process returns to step S7 (S8). When the signal ends (S7), Set end flag, ie ON
Then, the process returns to step S2 to wait for reception of access permission in the access permission information (S9).

If the end flag is ON in step S3, it is checked whether the next received access permission information is accessible. If not, the process returns to step S2 to wait for reception of access permission information (step S3). S10).
If the access permission / inhibition information received next in step S10 indicates that access is permitted, the end flag is reset and the process proceeds to step S4 for checking whether there is a transmission signal (S11).

[0013] By performing the above operation, when a plurality of mobile stations continuously transmit signals, the signals of the plurality of mobile stations are not significantly improved by a mobile station having a strong radio wave reaching the base station. Transmission becomes possible. Where RCR STD
As described in Standard 27, there is a method that employs a method of prohibiting random time access after an access failure in order to minimize access collision at the next timing after a random access failure. This has the effect of reducing the number of mobile stations colliding at the timing 404 in FIG. 3, for example, but does not affect the essence of the operation of this embodiment, and can be used together with this embodiment.

[0014]

As described above, according to the present invention,
In the mobile communication system, it is possible to prevent transmission of a mobile station located far from the base station from being hindered by continuous transmission of a signal by a mobile station located near the base station.

[Brief description of the drawings]

FIG. 1 is a diagram showing each functional configuration of a mobile station and a base station to which an embodiment of the present invention is applied.

FIG. 2 is a diagram showing an example of a transmission signal, its divided units, and the contents of unit division information.

FIG. 3 is a diagram showing examples of states of access permission / inhibition information, mobile station identification information to be allowed to transmit, access standby, success, and failure of each mobile station when the present invention is applied;

FIG. 4 is a flowchart showing an embodiment of a mobile station access control method.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04Q 7/28 H04L 12/28 (72) Inventor: Hidehide Sawayanagi 2-10-1 Toranomon, Minato-ku, Tokyo NTT -F-term in T-Mobile Communication Network Co., Ltd. (reference) 5K033 AA09 CA06 CB01 DA01 DA19 5K067 AA03 BB02 CC01 DD48 EE02 EE10 EE22 FF16 GG01 GG11 JJ02 JJ13 JJ22 JJ38 JJ74

Claims (2)

[Claims] An air line control type random access method in which a plurality of mobile stations communicate with a base station by sharing a framed radio channel and notify access permission / non-permission information from the base station to the mobile station. In the digital mobile communication method used, the mobile station transmits all units of a signal, and then, if there is a signal to be transmitted continuously, notifies access permission / non-permission information at least twice consecutively. A mobile communication random access method characterized by waiting for transmission of the signal until the signal is transmitted. 2. An air line control type random access method in which a plurality of mobile stations communicate with a base station by sharing a framed radio channel, and notify access permission information from the base station to the mobile station. In the digital mobile communication random access method used, when a signal to be transmitted is detected, a first step of waiting for reception of access permission information of access permission / inhibition information, and when the access permission is received, access transmission is performed in the case of the first transmission. And when the access permission is received, and when the transmission is continuous with the first transmission, the access permission information received next to the access permission information of the access permission is accessible. The process returns to the third step of determining whether or not the access is not permitted in the third step, and the first step of waiting for reception of the access permission of the access permission information. 4 and process, it is determined that access is possible in the third step, the digital mobile communication random access control method characterized by having a fifth step of access transmission.