JP2576777B2 - Communication Slot Assignment Method in Time Division Multiplex Communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital mobile radio communication system of a time division multiplex transmission system, in which a plurality of mobile stations share one or a plurality of radio communication slots and an inter-station data is transmitted between radio relay stations. The present invention relates to a control method of a communication slot of a wireless line and a digital line when the digital line is connected by a time division multiplex transmission system via an exchange.

[0002]

2. Description of the Related Art As a digital mobile radio communication system of the time division multiplex transmission system, an automobile telephone system or a portable telephone system has been constructed, and it is not affected by an ever-changing position of a mobile station. There is a communication control technique that constantly assigns a specific communication slot to each mobile station while constantly changing a dependent wireless relay station.

[0003] A method of adjusting the transmission timing of a time division multiplex transmission radio slot has already been established in a car telephone system and a satellite communication system.

However, a plurality of mobile stations share one or a plurality of time division multiplex radio communication slots, and the radio relay stations are connected by a time division multiplex transmission digital line via an interoffice data switch. In a system for performing standby communication, a communication control technique for assigning a communication slot in consideration of a transmission delay and adjusting a frame timing of a digital line is an unprecedented technique.

[0005]

A plurality of wireless relay stations accommodating a plurality of mobile stations sharing one or a plurality of communication channels are connected by a time-division multiplex transmission system digital line via an interoffice data switch. There are the following problems in the method of selecting a communication slot for a wireless line and a digital line in the system described above.

First, when a signal of an uplink radio slot from a mobile station received by a radio relay station is transferred to an uplink digital line, an uplink radio slot to be transferred and a slot of the uplink digital line to be transferred are transmitted. Is randomly selected, the transfer time becomes indefinite, causing a problem that the data transmission delay time increases. Therefore, before starting communication at the radio relay station, a combination of an uplink radio slot with a minimum transfer time and a line slot of an uplink digital is determined in advance, and the communication slot is assigned by such a combination of slots. Control to be performed is required.

Second, when a signal of a downlink digital line slot from the inter-station data exchange received by the radio relay station is transferred to the downlink radio line, the downlink digital line slot to be transferred and the downlink radio line to be transferred are transmitted. If the slot of the line is selected at random, the transfer time becomes indefinite, causing a problem that the data transmission delay time increases. for that reason,
Before starting communication at the wireless relay station, a combination of a downlink digital line slot with a minimum transfer time and a downlink wireless slot is determined.
Control performed by such a combination of slots is required.

Third, when the signal of the upstream digital line slot from the radio relay station received by the inter-station data exchange is transferred to the downstream digital line, the upstream digital line slot to be transferred and the downstream digital line to be transferred are transferred. If the slot of the line is selected at random, the transfer time becomes indefinite, causing a problem that the data transmission delay time increases. Therefore, before starting communication in the interoffice data exchange, the combination of the upstream and downstream digital line slots that minimizes the transfer time is determined, and the communication slot allocation is controlled by the combination of such slots. Is required.

Fourth, in the first and second methods in which the transfer time is shortened by a combination of slots, the time that can be shortened is a slot length unit, and there is a problem that the transfer time shorter than the slot length cannot be shortened. Therefore, it is necessary to perform control for finely adjusting the transfer time by adjusting the time difference between the frame timings of the wireless line and the digital line.

[0010]

In order to solve the above-mentioned problems, the present invention provides an inter-office data exchange with a combination of uplink and downlink digital line slots allocated for communication under conditions that minimize the transfer time. , Means for searching and determining before commencing communication. Furthermore, means for detecting the uplink and downlink digital channel reception frame timing for each radio relay station, which is information necessary for this determination, and the downlink digital channel transmission frame timing, Means is provided for fine-tuning the data transfer time to the slot.

Further, a means is provided for automatically determining a combination of wireless slots that minimizes the transfer time of data corresponding to the uplink and downlink digital line slots in the wireless relay station. Further, there is provided means for assisting detection of the frame timing of the upstream and downstream digital channels and fine adjustment of the transmission frame timing of the downstream digital channel. Here, there is no means for finely adjusting the transmission frame timing of the uplink digital line.

[0012]

Next, the present invention will be described with reference to the drawings. FIG. 1 shows an example of a system configuration which is a premise of the present invention. In the figure, 1 is an interoffice data exchange, 21, 22,
.., 2n indicate wireless relay stations, which are connected to the interoffice data switch 1 by a time division multiplex digital line 40. 31,3
,..., 3n indicate mobile stations, each of which is a radio relay station 2
, 2n and the time-division multiplexing radio circuits 51, 52,
, 5n are connected wirelessly. Time-division multiplexed wireless link 5
There are two types of wireless slots constituting 1, 52,..., 5n, a control slot for transmitting information for communication connection, and information for transmitting communication data information and terminating communication. There is a communication slot for transmitting the data. Similarly, the time-division multiplex digital line 40 is composed of two types, a control slot and a communication slot. However, the numbers of wireless relay stations, digital lines, mobile stations, and wireless lines shown in the figure are merely examples, and generally do not limit the numbers.

FIG. 2 shows a configuration of a data transmission route and a delay time. 1A is the transmission of the uplink radio circuit slot at the originating mobile station, 2A is the reception of the uplink radio circuit slot at the originating radio relay station, 2B is the transmission of the uplink digital circuit slot at the originating radio relay station, and 3A is the inter-station data exchange. , Reception of the downlink digital slot at the destination wireless relay station, 4B transmission of the downlink digital slot at the destination wireless relay station, 4B transmission of the downlink digital slot at the destination wireless relay station, and 5A indicates reception of a downlink radio channel slot from the terminating mobile station.

T1 is the transmission delay time of the uplink radio channel from the uplink radio channel slot transmission 1A at the originating mobile station to the uplink radio channel slot reception 2A at the originating radio relay station;
T2 is the data transfer time from the uplink wireless channel slot reception 2A to the digital channel slot transmission 2B, T3 is the transmission delay time of the uplink digital channel from the uplink digital channel slot transmission 2B to the uplink digital channel slot reception 3A, and T4 is the uplink digital channel Data transfer time from slot reception 3A to downlink digital line slot transmission 3B,
T5 is the transmission delay time of the downlink digital channel from the downlink digital channel slot transmission 3B to the downlink digital channel slot reception 4A, and T6 is the downlink digital channel slot reception 4A.
T7 indicates a data transfer time from downlink wireless channel slot transmission 4B, and T7 indicates a transmission delay time of the downlink wireless channel from downlink wireless channel slot transmission 4B to downlink wireless channel slot reception 5A. T2, T4, and T6 in FIG.
The means for shortening is described below.

FIG. 3 shows a data transfer time Tup from an uplink radio slot to an uplink digital line slot in a radio relay station. Uplink radio line UMA,
UMB and UMC form one frame with n radio slots, and the upstream digital line UDA also has the same frame structure, but the frame timing Toff
Are shifted by Tup + 1 slot length.

A frame configuration as shown in the figure and arrows A1,
If a combination of slots capable of performing transfer as indicated by A2 and A3 is performed, the wireless relay station does not take extra time storage time . Therefore, in the radio relay station, as described later,
The data transmitted from the interoffice data exchange in the control slot of the down-link digital line is used by the interoffice data exchange.
In response to the determined uplink communication slot designation information of the digital line, a search is made for a free communication slot from among the radio slots that are combined as indicated by the arrow, and if there is a corresponding uplink radio slot, it is immediately allocated. If the slot is occupied by another communication, wait until the slot becomes empty. However, the numbers of the uplink radio lines and the uplink digital lines shown in the figure are merely examples, and are generally not limited thereto.

FIG. 4 shows a data transfer time Tdown from the downstream digital slot to the downstream wireless slot in the wireless relay station. Downlink digital line D
DA forms one frame with n radio slots as in FIG. 3, and the downlink radio channels DMA, DMB and DMC have the same frame configuration.
It is shifted by down + 1 slot length.

The frame structure shown in FIG.
If a combination of slots capable of performing transfer as indicated by 1, B2, and B3 is performed, the wireless relay station does not take extra temporary storage time . Therefore, the wireless relay station will be described later.
As sent from the interoffice data exchange in the control slot of the downstream digital line , this interoffice data exchange uses
In response to the downlink call slot designation information of the digital line that has been decided to perform, a search for an empty communication slot is performed from among the wireless slots that are combined as indicated by the arrow,
If there is a corresponding downlink wireless slot, it is immediately allocated. If it is occupied by another communication, it waits until the slot becomes empty, and allocates it when it becomes empty. However, the number of downlink <br/> radio channel, and the downlink digital line shown in this diagram is an example,
This does not apply to a general.

FIG. 5 shows a radio relay station for detecting the frame timing of the up-link digital line, detecting and adjusting the frame timing of the down-link digital line, and determining the communication slot of the digital line and the communication slot of the radio line. FIG. 2 is an example of a block diagram of an interoffice data exchange.

This figure comprises an interoffice data switch 1 and radio relay stations 21 and 22. The interoffice data exchange 1 and the radio relay station 21 are connected to each other, and the interoffice data exchange 1 and the radio relay station 22 are connected by digital lines 41a and 41b and 42a and 42b, respectively.

The detection of the frame timing of the upstream digital line in the figure is performed as follows. Radio relay station 2
1, the frame timing detection data transmission circuit 21
From I, the frame timing detection data of the upstream digital line is transmitted. This data is sent to the digital line transmitter 21
From H , the signal is received by the digital line receiver 1A of the interoffice data switch 1 via the uplink digital line 41a, and the reception timing is measured by the frame timing measurement circuit 1D. The measured received timing data is, uplink digital
The frame timing is stored in the frame timing storage circuit 1E as the frame timing of the line . Connected via digital line 42a
Similarly, the other wireless relay station 22 detects the frame timing of the uplink digital line.

The detection and adjustment of the frame timing of the downstream digital line are performed as follows. Interoffice data exchange 1
From the frame timing detection data transmission circuit 1B,
And it sends the data frame timing detection of the downlink digital data Le line. This data from the digital line transmitting unit 1C, the lower
The signal is received by the digital line receiver 21J of the wireless relay station via the digital line 41b , and the reception timing is measured by the frame timing measurement circuit 21G. In the frame timing measurement circuit 21G, the wireless relay station further includes
A frame timing signal of the downlink radio channel transmitted from the radio channel transmission unit 21B of the time division multiplex transmission system for communicating with the mobile station is compared with measured reception timing data, and information on the difference is used as a frame timing measurement circuit. 21G
To the inter-office data exchange 1 via the upstream digital line 41a . In the interoffice data exchange 1, the information on the difference is received by the frame timing measurement circuit 1D via the digital line receiving section 1A, and based on the received information, the frame timing adjustment of the downstream digital line is transmitted to the digital line. line intends for the part 1C. The adjusted frame timing data is stored in the frame timing storage circuit 1E. The interoffice data exchange 1 and the wireless relay station 21
And 22 is exchanged with some bit information in the control and communication slots. Do not elaborate further
According to the above, the frame timing detection data described above is
Or in the first slot of the frame of the downstream digital line
It is built into. At this time,
The first slot of a digital line frame is occupied by communications.
Regardless of whether they are sent. Therefore communication
When the communication data is not
Since there is no data, the dummy data is transmitted.

In the figure, allocation of communication slots for digital lines is performed as follows using control slots for digital lines. When a call request signal from a mobile station is received by the radio line receiving unit 21A of the radio relay station 21 and received by the communication slot determination circuit 1F of the interoffice data switch 1 via the digital line 41a, the communication slot determination circuit 1
F receives the upstream frame timing of the upstream digital line 41a and the downstream frame timing information of the downstream digital line 42b from the frame timing storage circuit 1E, calculates the time difference between them, and obtains the upstream time at which the data transfer time in the interoffice data switch 1 becomes minimum. Digital line and downlink
A combination of digital line slots is determined, and the corresponding combination of communication slots is determined by the communication slot monitoring circuit 1.
Search with G. If the slot is empty , the communication slot monitoring circuit 1G places the slot in a reserved state and immediately notifies the communication slot determination circuit 1F. The communication slot determination circuit 1F immediately transmits the information through the downstream digital line 41b.
It is transmitted to the communication slot determination circuit 21E of the wireless relay station 21 at the current position . Also, if the slot is not empty, wait until slot corresponding to the combination is free, open to the slot as the reservation state in <br/> time notified to the communication slot determination circuit 1F, a communication slot determined The circuit 1F sends the information to the communication slot determination circuit 21E of the wireless relay station 21 via the downlink digital line 41b. Also , wireless relay
Similarly, the communication slot of the determined digital line is transmitted to the station 22 .
The transmission information is transmitted through the route of the downstream digital line 42b . Then, when the notification of the acquisition of the communication slot of the radio channel , which will be described later, is transferred from the radio relay stations 21 and 22 to the communication slot determination circuit 1F of the interoffice data switch 1 through the uplink digital channels 41a and 42a. The communication slot determination circuit 1F notifies the start of communication to the communication slot determination circuit 21E of the wireless relay station 21 and the same circuit of the wireless relay station 22.

[0024] and have you in the figure, the allocation of communication for the slot of wireless access in the radio relay station is carried out in the following manner. In the case of the wireless relay station 21, the communication slot assignment information of the digital line communication slot
After accepting in E, the digital line slot and wireless
The slot of the wireless line that minimizes the data transfer time with the slot of the line is calculated, and the corresponding slot is searched by the communication slot monitoring circuit 21D. The slot is empty
If the communication slot monitoring circuit 21D is immediately notified to the communication slot decision circuit 21E to the slot and the reservation states. The communication slot determination circuit 21E sends a communication slot acquisition notification of the wireless line to the interoffice data exchange 1 via the upstream digital line 41a. Also, that slot
If not empty, waiting until the slot is free, the radio slot vacated <br/> time and reservation state, and notifies the communication slot decision circuit 21E.

The communication slot determination circuit 21E sends a notification of the acquisition of a communication slot for the wireless line to the interoffice data switch 1 via the digital line 41a. After receiving the same communication slot assignment information from the interoffice data switch 1, the wireless relay station 22 also performs the same control as the wireless relay station 21. The exchanges between the interoffice data exchange 1 and the wireless relay stations 21 and 22 on the digital line are all performed using control slots. However, in general, the number of wireless relay stations connected to the interoffice data exchange by a digital line is three or more.

[0026]

As described above, according to the communication slot search method of the present invention, the upstream and downstream digital line slots used in the communication are delayed by the transfer before starting the communication. By searching for a slot combination that minimizes the time and providing a means for allocating the corresponding slot when the slot corresponding to the combination becomes vacant, the slot data transfer at the interoffice data switch during communication can be performed. This has the effect of shortening the delay time.

In the radio relay station, there is provided a means for allocating a radio slot which minimizes the transfer time with the radio line based on the digital line slot designation information received from the interoffice data switch before starting communication. This has the effect of reducing the delay time due to the transfer of slot data at the wireless relay station during actual communication.

Further, by providing a means for adjusting the frame timing of the downlink digital channel in the radio relay station, there is an effect that the delay time due to data transfer from the downlink digital channel to the downlink radio channel can be further reduced.

With these effects, the transmission delay of communication in the entire system can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a system configuration which is a premise of the present invention.

FIG. 2 is a diagram showing a configuration of a data transmission path and a delay time.

FIG. 3 is a diagram showing a data transfer time from a wireless slot to a digital line slot in a wireless relay station;

FIG. 4 is a diagram illustrating a data transfer time from a downlink digital circuit slot to a downlink wireless slot in a wireless relay station.

FIG. 5 is a block diagram showing a configuration of a wireless relay station and an interoffice data switch in one embodiment of the present invention.

[Explanation of symbols]

, 2n Radio relay stations 31, 31, ..., 3n Mobile stations 40, 41a, 41b, 42a, 42b Time division multiplex digital circuits 51, 52, ..., 5n Time division multiplex radio circuits

Claims (1)

(57) [Claims] A plurality of mobile stations and one or more communication channels;
Communication over a time-division multiplex transmission wireless line
Wireless relay station to perform and time-division
Comprises an inter-office data exchange connected by a dual digital line
In the mobile communication system to be performed, the frame tie between the up line and the down line of the digital line is used.
Digital line frame timing that detects and adjusts timing
The frame detection and adjustment means includes a frame transmitted by the wireless relay station to an uplink digital line.
The timing detection data is received and the
Be prepared for the inter-station data exchange that measures frame timing.
The obtained first frame timing measuring means, and the frame transmitted by the inter-office data exchange to the downstream digital line.
Frame timing detection data and the radio relay station transmits
Receive the frame timing signal of the
Digital line frame timing and wireless line frame
Before the timing difference information via the upstream digital line.
Be prepared for the wireless relay station to be returned to the interoffice data exchange.
Second frame timing measuring means, and the second frame timing measuring means returned by the second frame timing measuring means.
Frame tie of downlink digital line based on difference information
A firmware provided in the interoffice data exchange for adjusting
Frame timing adjusting means, and the uplink measured by the first frame timing measuring means.
Digital line frame timing information and said frame
The timing of the downstream digital line adjusted by the timing adjustment means
In the interoffice data switch which stores the
Is composed of a gill frame timing storage means, said digital in the station between the data exchange at call set
First communication slot determination for determining communication slot of line
The means may be a communication target from the frame timing storage circuit.
Digital circuit frame timing information and downlink digital
Receives the frame timing information of the
Calculate the time difference between
Minimal slot data transfer time to downstream digital line
The combination of slots that will be
Determined from digital line and assigned communication slot
And transmit the assigned communication slot information to the downlink digital
Means for transferring data to the wireless relay station via a wireless line , wherein the wireless relay station transmits the wireless
Second communication slot determining means for determining a line slot
Is the digital data transferred from the first communication slot determining means.
Receive the communication slot information of the
Line communication slot and slot data transfer time is minimum
And determine the wireless line slot to be used.
Line slot information is transmitted to the inter-station
When, characterized in that it comprises means for transferring the over data exchange
Allocation scheme of the communication slots in division multiplex communication.