JPS58207746A - Transmission system of control signal - Google Patents

Abstract

PURPOSE:To shorten the time required for connection of a line, by making a delay time from the reception of a retransmission request at each terminal station to the retransmission different. CONSTITUTION:When the terminal stations A, B make a call at the same time, supposing that a central station recognizes the presence of a call signal but can not confirm the content sufficiently because of collision. Then, after the central station determines the number of frames definitely from the receiving frame of errorneous data of an outgoing control signal to the request of retransmission, e.g., two frames, the central station proposes the retransmission request. Thus, since the terminal stations A, B receive the retransmission request two frames after the calling, it is discriminated that the central station receives the call signal of the own station in error. Then, the call signal is retransmitted, and this signal uses a different delay time from each terminal station or each retransmission, allowing to prevent the collision of the call signal again.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention provides a method for transmitting and receiving control signals from a G terminal station to a central station when a plurality of terminal stations exchange control $1 signals with a central station using a common control channel. The control signal is transmitted downstream from the central station.
The present invention relates to a system that enables channel sharing by synchronizing with the frame of the J control signal and making the signal length less than or equal to one frame of the downlink control signal, and relates to a control signal transmission method with short line connection time.

(b) Background of the technology In a system consisting of a large number of terminal stations that randomly send out call signals (hereinafter referred to as "call number 1") to a central station, the number of terminal stations is extremely large. However, in cases where the call time of each terminal station is very short, it is not preferable to allocate a dedicated call channel or transmission path to each terminal station because the channel utilization efficiency is extremely low. Therefore, in such a case, a plurality of communication channels are shared by a large number of terminal stations, and the central office allocates an empty communication channel to the calling terminal station based on the calling signal from the terminal station.

The so-called multi-channel access method improves channel usage efficiency. In these systems, the exchange of control signals between the terminal station and the central station, such as a call signal from the terminal station to the central station and a channel assignment signal from the central station to the terminal station, is usually common to these terminal stations. This is done via a control channel.

However, when many terminal stations share a control channel, calls from each terminal station occur randomly.
At the same time, two or more terminal stations may send calling signals through the same control channel, causing a collision and not being received correctly by the central station.

Furthermore, when using an uplink control channel from the terminal station to the central station and a downlink control channel from the central station to the terminal station, a code error (1>1) may occur.

The present invention aims to shorten the time it takes to connect a line in such a case.

(C) Conventional technology and problems When a certain amount of code errors occur in the transmission system, even though the terminal station sends out a call signal to increase reliability,
It is known to retransmit a call signal when no response signal is obtained from the central office.

FIG. 1 shows the flowchart. However, if multiple terminal stations make simultaneous calls, collisions will occur, and if a simple retransmission method is adopted in this case, the retransmitted signals will collide again. For this reason, the confirmation signal waiting time is changed for each terminal station, and retransmission is performed after the confirmation signal waiting time has elapsed. In the chart 70 of FIG. 2, the response signal waiting time is the same, but the delay time from the time-out to retransmission is changed for each terminal station or for each retransmission. However, with the above method, even if an error occurs on the lower control channel and the calling signals do not collide, the terminal station will still In order to retransmit the response signal, the former method requires waiting until the response signal waiting time has expired, and terminal stations with long waiting times have the disadvantage that it takes a long time to connect the line. Since the waiting time t has exceeded and retransmission is performed after further waiting for the delay time before retransmission, terminal stations with a long delay time until retransmission have the disadvantage that it takes a long time to connect the line (d) Purpose of the Invention The present invention The object of the present invention is to provide a control signal transmission system that eliminates the above-mentioned drawbacks and can shorten the time required to connect a line in the event that calling signals collide or an error occurs in the uplink or downlink control channels.

(e) Structure of the Invention In order to achieve the above-mentioned object, the present invention provides for the transmission of uplink control signals from each terminal station when a plurality of terminal stations exchange control signals with a central station using a common control channel. In a system that enables sharing of a control channel by synchronizing the downlink control signal with the frame of the downlink control signal from the central station and making the signal length one frame length or less of the downlink control signal, the central station Due to collision or signal error,
If the company can determine that there is a call from the terminal station, but the content cannot be confirmed sufficiently, it does not wait for the 7th frame of the downlink control signal that determines that there is a call signal, but until the frame that outputs the response signal in the case of normal reception. A control signal (pitch f) that makes a retransmission request is sent on the uniquely determined frame, and if possible, the terminal station determines whether or not there is a retransmission request for itself. When a station-directed retransmission request is received, it is determined that no response signal is received, and at that point, the terminal station that made the call is retransmitted after a different delay time determined for each terminal station. If the forwarding retransmission request is not received and no response signal is obtained during the response signal waiting time, it is determined that an error has occurred in the downlink control signal, and the downlink control signal is immediately retransmitted to shorten the time required for retransmission. It is characterized by 1.

(f) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a time chart showing an example of the temporal relationship of uplink and downlink control signals between the central station and the terminal stations to which the present invention is applied.

The calling signal in B) is synchronized with the frame of the downlink control signal shown in (a), and the signal length is less than or equal to the length of one frame of the downlink control signal fa), and the central station calls each terminal station (A). ,B)
When a calling signal is received from the terminal station, a response signal is sent to each terminal station after a predetermined frame in order to respond.

FIG. 4 shows the frame 7 format of the lower 9 control signals according to the embodiment of the present invention. In addition to the frame synchronization signal and information for each terminal station, a control bit area 1 is provided, and a retransmission request is sent to all terminal stations in this area. FIG. 8 is a flowchart of the operation of the terminal station according to the embodiment of the present invention, and FIG. 9 is a flowchart of the operation of the central station according to the embodiment of the present invention. .

Figure 5 is a time chart for the case (b) in which terminal stations A and B make simultaneous calls in an embodiment of the present invention, and it can be seen that there was one calling signal at the central station because the calling signals collided. If the content cannot be confirmed sufficiently, the central station sends a retransmission request after uniquely determining the period from the error data reception frame of the downlink control signal (a) to the retransmission request (two frames in this example).

These two frames are selected as early as possible based on time + [i] than the frame that sends the response signal.
Since it receives a two-frame temporary retransmission request after making a call, it can be seen that the central station has received its own calling signal in error. Therefore, the calling signal is forwarded, but this takes a different delay time for each terminal station or for each repeater, and this time, in FIG. 5, is m frames for station A.

Station B retransmits after n frames. This prevents the calling signals from colliding again. If an error occurs in the uplink control channel and, for example, the central station mistakenly receives the calling signal from station A, it will issue a retransmission request two frames later in the same way as above, and station A will issue a retransmission request. Receive, from t
The calling 111 signal is retransmitted after n frames. This retransmission signal performs the above operation n
Repeat several times and abandon if no confirmation signal is obtained. still,
In the flowchart of FIG. 8, the confirmation signal is seen during a delay time that differs for each terminal station. This is a measure to be taken when the terminal station receives an erroneous retransmission request due to an error in the downlink control channel or the like.

FIG. 6 is a time chart of an embodiment of the present invention when an error occurs in the response signal on the lower control channel. When an error occurs in the lower 9 control channels, in the conventional example, after the response signal waiting timer overflows, each terminal station retransmits the entire call signal after a different predetermined delay time. In this case, there is no retransmission request for all terminal stations, so the calling signal is received by the central station without error, and it can be determined that there was no collision in the calling signal.
If the response signal waiting timer overflows, the entire calling signal is immediately retransmitted. This situation k (al
In response to the lower control signal shown in (bJ), terminal station A sends a call trigger signal, and the central station receives this, so it does not issue a retransmission request two frames later, and terminal station A However, an error occurs on the lower control channel and the response signal does not come to terminal station A. When the response signal waiting timer overflows, terminal station A immediately retransmits the entire calling signal. It shows that.

FIG. 7 is a time chart when a retransmission request is received in the third frame after terminal station A makes a call in the embodiment of the present invention. For the downlink control signal (alK), as shown in (b), terminal station A makes a call in the first frame, and
If terminal station B and terminal station C make a call in the th frame, the calling signals of terminal station B and terminal station C will collide, so
The central station sends a retransmission request to all terminal stations in the fourth 7 frames, but terminal station A ignores this and responds, since the retransmission request is made less than two frames after the call is made. wait. Therefore, the subsequent confirmation signal for station A can be received normally. Terminal stations B and C received a retransmission request 27 frames after the call was made, indicating that a collision or error had occurred on the uplink control channel and that the central station could not receive the call. As described above, according to the present invention, when an error occurs in the terminal station's calling signal on the uplink control channel, the central station retransmits the calling signal after n frames or θ frames. In this example, a retransmission request is sent two frames later before the response signal is issued, so the time required to connect the line is shortened by this time difference. Also, if a response signal error occurs on the downlink control channel, the retransmission request is sent two frames later. Since the calling signal is retransmitted immediately after the signal waiting timer overflows, it is retransmitted earlier by a predetermined delay time for each terminal station, and the time until line connection is shortened by this amount.

This effect becomes more significant as the number of retransmitted calls increases.

The above operation can be easily realized by making the programs of the central station and terminal stations compatible with this.

(b)) Effects of the Invention As explained in detail above, according to the present invention, in the event of a collision of calling signals or an error occurring in the uplink or downlink control channels, the time required to connect the line can be shortened. There is.

[Brief explanation of the drawing]

1 and 2 are flowcharts of the operation of a conventional terminal station, and FIG. 3 shows an example of the temporal relationship of uplink and downlink control signals between the central station and the terminal station to which the present invention is applied. FIG. 4 is a time chart of the downlink control signal frame format according to the embodiment of the present invention, FIG. 5 is a time chart when terminal stations A and B call simultaneously during implementation of the present invention, and FIG. FIG. 7 is a time chart when an error occurs in the lower control channel according to the embodiment of the present invention. 8 is a flowchart of the operation of the terminal station according to the embodiment of the present invention, and FIG. 9 is a flowchart of the operation of the central station according to the embodiment of the present invention. Fig. 2 Rain Fig. 8 Fig. 1 210 = Fig. 9 - -1-, -

Claims (1)

[Claims] When multiple terminal stations exchange control signals with the central station using a common control channel, the upper 9
In a system that makes it possible to share a control channel by synchronizing a control signal with 7 frames of a lower control signal from the central station and making the signal length one frame length or less of the lower control signal, If the central station can determine that there is an uplink control signal 4N from the terminal station, but cannot confirm the content sufficiently, it can check the case of normal reception from the frame of the downlink control signal that has been determined to have the uplink control signal. Without waiting until the frame that sends the signal, all control bits are inserted into a predetermined control bit area on the frame after the frame, and each terminal station requests retransmission. The delay time from receiving to resending is set to be different.
Each terminal station that sent out the upper 9 control signal will retransmit the upper 9 control signal with a delay of W, and if the terminal station that sent the uplink control signal does not receive the retransmission request and the central station・If one word is not received within the waiting time, the uplink control signal must be retransmitted immediately.
-Characteristic control signal transmission method.