JPH0468722A - Statistic multiplex radio accessing system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field to which the Invention Pertains) The present invention relates to a wireless mobile communication system such as a car telephone, in which a time division multiplexing method is used for wireless transmission between a base station and a mobile terminal. This invention relates to a method of multiplexing user information into channels.

(Prior art and its problems) The time division multiplexing system (referred to as % A) in a wireless mobile communication system uses a fixed time interval (length approximately 5 ms to 20 m5) called a TDMA frame, as shown in Fig. 5.
Further time slot (Time 5lot: TS
The TS is divided into even smaller fixed intervals called TSs, and each TS is divided into the mobile terminals that are currently talking (Termi).
nal (hereinafter referred to as TERM), thereby securing a communication path between the base station (hereinafter referred to as BS) and TERM.

Telephone voice requires simultaneous transmission in both directions, so TDM
The TS included in the A frame is first divided into two as shown in Figure 5, one of which is used to transmit the call signal from the BS to the TERM, and the other half is used to transmit the call signal from the TERM to the BS. Furthermore, a pair of identically numbered TSs of both parts are assigned to one TERM.

Each TS in one TDMA frame shown in FIG.
S from one BS to each TERM, and from one BS to each TERM
- Each TS in the BS portion is transmitted from each TERM toward the BS on radio waves. Each TS to BS and each TE
In order to discriminate individually in RM, BS and total TER are required.
It is necessary to operate in synchronization with the timing specified by M or TDMA frames. This timing usually differs depending on whether it is transmitted by radio waves from the BS to all TERMs, the length of the transmission path, or the location of the TERMs, so the difference in propagation time causes a "shift" in the recognition of timing in each TERM. In order to absorb this "shift", a guard time (referred to as GT) is provided between each TS.

Furthermore, in each TERM, when receiving radio waves from the BS, reception on a wireless carrier is started at the start of the assigned TS, and reception is stopped at the end of the TS. Regarding reception, although there is no problem in terms of operation principle if each TERM or all TSs are received, the above-described operation is normally performed in order to save power consumption of the TERM. On the other hand, when transmitting from a TERM, the assigned T
Is it necessary to start transmitting the wireless carrier at the start of S and stop transmission at the end of TS? In order to start and stop transmission and reception of this wireless carrier, several preamble bits (referred to as PU) are placed before and after each TS.

In addition, C0NT (Control Part
) section is used for communication between the BS and TERM during a call (various status displays, status switching instructions, etc.). Furthermore, although not shown in the figure, the CoNT section includes codes necessary for frame synchronization and carrier modulation method.
Consists of 0 bits. The remaining part of the TS is the part that carries user information (User Data), which also includes error detection bits (ECC) such as parity.

Now, in the conventional example with the above configuration, a call connection control channel (not shown) is used to exchange control information regarding call origination or call arrival between the BS and the TERM, and a call is set up. One pair of TS (BS-TERM and TERM
→ Select one TS from each BS and assign it to the call. Thereafter, these TSs are held on that call until the end of the call, and are released at the end of the call.

Traditionally, telephone voice was the mainstream user information, so there was no practical problem with such a simple TS allocation formula, but with the shift to 15DN in wired networks, user information now includes data in addition to telephone voice. As a result, the bit rate and the amount of information transmitted and received differ from call to call, resulting in a disadvantage that the efficiency of using the wireless channel becomes low.

(Object of the Invention) The present invention is directed to a radio mobile communication system or a public telephone network.
When transmitting multiple information such as data and still images in addition to voice in response to the The purpose of this invention is to provide a statistical multiplexing radio access system that increases the number of calls that can be connected in a band.

(Structure and operation of the invention) FIG. 4 is a side view of the structure of a wireless mobile communication system to which the present invention is applied. Public telephone network (PSTN)
5w1tched Te1ephon Network
) or Public Integrated Services Digital Network (IsD)
N:rntegratedService Digi
tal Network> is a digital synchronous multilayer line (SDH: 5 synchronous digital network).
base station (B S
: Ba5e 5tation) is connected.

Depending on the traffic situation, the traffic of multiple BSs may be transferred to a remote line concentrator (RLC) as shown in the figure.
(Line Concentrator) and connected to PSTN or 15DN.

The information transferred by SDH is either telephone voice or data, whether it is transmitted in circuit-switched form, or
Connection to both A5IC and Primary standardized ink interfaces is possible.

The BS in the figure is, for example, installed corresponding to a microcell of a local mobile communication system, and connected to a similar cell S installed in another remote cell via PSTN or 15DN.
Each BS is connected to mobile terminals in the corresponding cell through a radio channel, and ultimately mobile terminals in mutually remote cells connect the BS to the PSTN or l5.
It will be connected via DN.

The present invention provides a link between a BS and a mobile terminal (TER) in the system.
M).

The basic configuration of the wireless access of the present invention is the same as that of conventional TDMA. In addition, each time slot (TS) of TDMA
The control method for assigning TERM to each call is also the same as the conventional TDM.
It may be exactly the same as A.

FIG. 1 is an explanatory diagram showing an example of the bit configuration of a TS in an embodiment of the present invention. Figure 1 (1) shows the basic configuration of the TS.
) is the same as the conventional example shown in Fig. 5, but in the present invention, as shown in Fig. 1 (2), 6T
S(7) SMAC between CONT and USERDATA
(Stochastic Multiple Access
By providing a ss Control section, each T
This makes it possible to allocate S to a call requiring transfer of user information for each TDMA frame (perform dynamic demand assignment for each frame). In other words, the dynamic
Due to dayman assignment, it is possible to multiplex user information for one call and a plurality of calls on a wireless channel by utilizing the fact that the times at which user information transfer requests occur are statistically distributed.

For this reason, the multiplexing method of the present invention is based on statistical multiple access (S
MA: 5tochastic Multiple
This is called the ``Access'' method.

The SMAC in Figure 1 (2) uses the SMA method to
This is used to notify the TERM from the BS that S has been allocated. The operation sequence for this purpose is shown in FIGS. 2 and 3.

Figure 2 shows the case where user information is transferred from the BS to the TERM, and in the frame before the actual transfer of user information, an instruction is sent from the BS to the TERM to indicate whether to transfer it using SMAC or TS. Based on this instruction, the TERM takes in user information addressed to its own TERM from the designated TS of the next frame.

FIG. 3 shows a case where user information is transferred from TERM to BS. TERM is used when there is information to be transferred to the BS.
Since there is no SMAC part in the TS from ERM to BS, T
T by the C0NT part of the TS sent from ERM to BS
Request S allocation. The BS allocates the TERMi:TS in response to this allocation request, and sends a designation notification to the TERM using the SMAC unit as in the case of FIG. 2. TERM transfers the user information to the BS using the assigned TS of the next frame. If there is still more information to be sent at this time, the C0NT section of this TS requests TS allocation at the same time. TER
A TS allocation request from M to BS cannot be sent unless a TS for information transfer from TERM to BS is allocated, so BS cannot send transfer information for calls that transfer information in SMA mote or for TERM that is set up. Periodically (for example, once every few 10 frames) to inquire about the presence or absence of T.
Allocates a TS for information transfer from the ERM to the BS.

The operations of TS allocation request, TS allocation specification, and user information transfer in Figures 2 and 3 can be executed independently or simultaneously in parallel, so TS allocation specification and user information transfer are performed in the same frame. A so-called pipeline operation is possible, and there is no possibility that the user information transfer is hindered by the TS allocation specification and the information throughput is reduced.

FIG. 6 is a control flowchart for performing the above operations, and shows call connection and user information transfer control.

1(3) and (4) are detailed bit configuration diagrams of the SMAC section provided according to the present invention in FIG. 1(2).

FIG. 1 (4) shows an example in which TS allocation is performed for two TERMs. In the figure, S/T is one bit indicating whether or not TS allocation by SMA is to be performed. For example, the case where it is performed is indicated by a logic "1". Next term
AD indicates the address of one of the two TERMs, and if this is, for example, 3 bits, 8 bits per TS.
It is possible to specify up to 3 TERMs. The next T/R indicates whether the assigned TS or TERM is used for transmitting or receiving user information. The next TSAL indicates the number of the TS to be assigned. For example, by a bit pattern corresponding to each TS that the BS has, the bit corresponding to the assigned TS is indicated by logic "1", and the other bits are indicated by logic "0". The next C/lower is 1 bit indicating whether or not there is a further TS allocation designation, and it is a logic “1” bit.
” indicates that TS allocation specifications for other TERMs will follow, and as shown in the figure, after P, other TE
TS designation for RM is done in the same manner as described above. If C/lower is a logic "0", it indicates that this is the trailing edge of the SMAC section. The next P under C/ is a parity check attached to each TS allocation specification for the relevant TERM, and in some cases an error correction code (EC
C: Error CorrectingCode).

FIG. 1(3) shows a case where no TS allocation is specified for the TS, and the S/T becomes, for example, a logic "O" and a parity bit P is attached to it.

Next, the operation of the embodiment of the present invention will be explained. Although not shown in Fig. 1, there is a call connection control channel, which is a device configuration that mutually transfers control information between the BS and TERM in order to allocate a time slot (time slot to the TERM that performs call setup) during call setup. and operation is similar to conventional TDMA.

In the present invention, one part of the TS is changed to the TE for each call setup, as in the past.
It is also possible to allocate it to RM. Therefore, it is also possible to bring a mobile terminal used in the conventional system into the area of the system operated in the embodiment of the present invention.

Now, when a call is set up by calling a TERM that performs TS allocation using an SMA, or by receiving a call from such a TERM, the BS sends the TS for TS allocation specification and the TERM address to be used at that time to the TERM. number and notify it to the corresponding TERM. The method of designation and notification at this time can be easily inferred from the method of designating a TS in TDMA. TER for one TS
As many TERMs as can be expressed by the bit length of M AD
can be made to correspond. Therefore, for example, B in 1)
If S has n TSs and TERM AD is 3 bits, then there are a maximum of 8Xn TER'Mi:.

You can set up a call.

The SMAC section becomes as shown in FIG. 1 (3) for a frame in which there is no information to be transmitted even after a call is set up, and as shown in FIG. 1 (4) when there is information to be transmitted.

TS allocation specification by SMA is valid for one frame only, and is specified for each frame as necessary. In addition, it is possible to allocate multiple TSs to one TERM within one frame, and the number of TSs to be allocated is determined based on the amount of user information to be transmitted and the status of TS free/occupied TSs.
It is determined as appropriate by the S allocation program.

Following the TS SMAC used for TS allocation specification <USE
The RDATA part is the TER specified in the previous frame
It is used for user information transfer between M and BS. TERM of this user information transfer destination and destination TERM of TS allocation specification
can be determined completely independently of each other. That is, T
It may be the same as or different from the destination TERM specified for S allocation.

Therefore, the TS sent from the BS to the TERM will be received by a TERM that receives SMAC, a TERM that receives USERDATA, and a plurality of TERMs.

In addition, when transmitting user information from TERM to BS, the desired number of TSs to be allocated is sent from TERM to BS using the C0NT part at the same time as the TS allocation request according to the amount of information to be transmitted, and the BS side informs the BS of available TSs. Check the blockage situation and make TS as appropriate.
Decide on the number of quotas. If the allocated TS cannot send all the user information and there is residual information, a request for TS allocation is made again.

(Effect of the invention) The effects and advantages of implementing the present invention are as follows.

(1) Improve the efficiency of wireless channel usage. In the TDMA system, the TS is put on hold as long as the call is set up. In the case of bidirectional pair control, two TSs are reserved. but,
The time during which the audio signal is actually flowing during this hold time (
In most cases, the ratio of voiced sections is less than 50%, so even if the SMAC part is used for SMA control, it can be expected that the usage efficiency will be improved by at least twice as much.

In the case of data, since most of the uses will be much lower than the minimum line throughput that can be set with TDMA, it is possible to improve the usage efficiency by about 10 times.

(2) The same multiplexing system can flexibly respond to the different required throughputs of the various media being handled.

In other words, from media that requires high-speed throughput such that one terminal occupies all TSs of the BS, the TSs of the BS are
It is possible to support media that requires low-speed throughput connections to many times the number of terminals by simply changing the frequency of TS allocation.

(3) It is completely compatible and compatible with the conventional TDMA system, and even if a terminal for the TDMA system is brought in, the BS side recognizes the type of the terminal and transmits the TDMA system to that terminal. Assign the TS using the SM method.
Mixing with A-type terminals can be completely permitted. This also means that only TDMA and SMA can be used depending on the media, and the system has great flexibility. In other words, for voice calls that are extremely sensitive to transfer delays and variations in transfer delays, TDMA is used to set up calls, and for data calls that have large tolerances for both delays and delay variations, SMA is used. .

[Brief explanation of drawings]

FIG. 1 is a diagram of the bit configuration in the TS for specifying TS allocation in the embodiment of the present invention, and FIG. 2 is a diagram of the TER from the TS of the present invention.
FIG. 3 is a control sequence when transmitting user information from TERM to BS of the present invention; FIG. 4 is a side view of the configuration of a network to which the present invention is applied; FIG. The figure is a side view of the frame structure of a conventional TDMA radio channel, and FIG. 6 is a flowchart showing the operation control of the present invention. agent

Claims (7)

[Claims] (1) In a system where a base station performs bidirectional communication with multiple terminals within its service area using time-division multiplexed time slots, each time slot is assigned to which terminal within the time slots transmitted from the base station to the terminal. A first part is provided with a plurality of bit positions for specifying which bit positions to allocate, and when there is user information to be transferred, the first part is used for each time-division frame in a time-division multiplexing system to assign bit positions to the next frame. A statistical multiplexing radio access system in which control is performed to notify the relevant terminal of the allocation designation of multiple time slots according to the amount of information to be transferred. (2) The scope of the claim is such that control is performed to independently designate the destination terminal of the first part of each time slot and the second part consisting of a plurality of bit positions for transferring user information. The statistical multiplexing radio access method according to paragraph 1. (3) If there is no information to be transferred and there is no need to notify the time slot allocation designation using the first part,
The first part is only a bit indicating that there is no time slot allocation in that frame, and the remaining bit positions of the first part are renormalized into the second part and used for transferring user information. A statistical multiplexing radio access system according to claims 1 and 2, in which control is performed such that: (4) When specifying time slot allocation for each terminal, the specified time slot is used for transmission from the base station to the terminal or from the terminal to the base station for each frame or the first part. The statistical multiplexing radio access system according to claim 1, further comprising a bit position indicating either one of the following. (5) According to claim 1, the first part is provided with a bit position for independently specifying time slot allocation to a plurality of terminals of a certain number or less for each terminal. statistical multiplexing radio access scheme. (6) To transfer user information from the terminal to the base station,
A third portion consisting of a plurality of bit positions for transmitting control signals from the terminal to the base station is provided within the time slot, and the third portion comprises bit positions necessary for transmitting control signals from the terminal to the base station. The statistical multiplexing radio access system according to claim 1, wherein the statistical multiplexing radio access system performs control to request a number of time slot allocations. (7) The statistical multiplexing radio access system according to claim 1, wherein the base station performs control to periodically allocate time slots for transfer from the terminal to the base station to each terminal.