JPS6135036A - Transmitter for multiple address communication - Google Patents

Abstract

PURPOSE:To attain automatic retransmission control with less number of times of retransmission by comparing a content of a reception response inputted from a receiver with a content of a reception state storage circuit by a reception decision circuit so as to apply retransmission control and writing the reception state of each reception station to the reception state storage circuit. CONSTITUTION:An information frame to be transmitted is transmitted from a transmitter 3 via a transmission information addition circuit 2 from a buffer 1 and a receiver 6 receives a reception response from each reception station. The reception response received is inputted to a reception decision circuit 7 and when the reception response is a reception confirmation, the circuit 7 updates a frame after reception confirmation by each reception station written in a reception state storage circuit 8. If the reception response is a retransmission re-request, the content of a retransmission register 5 is transmitted to the retransmission request received at first and retransmitted to a prescribed number of frames and when the 2nd and succeeding retransmission requests comes from the same station, the requested information frame is retransmitted from the buffer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The present invention relates to a transmitting device in a transmitting station when performing broadcast type communication in a packet communication system.

(Prior Art and its Problems) Communication in which there are multiple communication partners and the same information is transferred simultaneously to multiple destinations is called broadcast communication. Automatic error retransmission control (ARQ: AUTOMA) in broadcast communication
Various protocols for TICREPEAT REQUEST have been proposed, and one of them is a method called a selective retransmission method (5EIJCTIVE REPEAT). In this system, the transmitting station transmits a plurality of information frames, and if the receiving station detects an error in the transmitted information frame, it issues a retransmission request to the transmitting station. The transmitting station then retransmits only the information frame for which a retransmission request has been made due to erroneous reception from the receiving station.

However, unlike in the case of one-to-one communication, since there are a plurality of receiving stations, the frames that are erroneously received generally differ for each reception.

For example, 101r sent by a transmitting station! Among the information frames of A, receiving station 1 incorrectly receives the second frame, receiving station 2 receives the seventh frame, and receiving station 3 incorrectly receives the ninth frame. In response to a retransmission request from the station, we have to retransmit three frames: the second frame, the seventh frame, and the ninth frame. However, in this case, only receiving station 1 has received the second frame in error, and the other receiving stations have already received the second frame. In this way, although each receiving station needs to retransmit one frame at a time, the transmitting station must retransmit three frames. This leads to a decrease in the utilization efficiency of the packet communication channel.

(Objective of the Invention) An object of the present invention is that when each receiving station receives at most one frame in error as in the above example, even if the received frame is different in each receiving station, An object of the present invention is to provide a transmitting device that can simultaneously achieve retransmission to all receiving stations by retransmitting one frame.

(Structure of the Invention) According to the present invention, there is a buffer that stores and outputs information frames to be transmitted frame by frame, and adds transmission information to the information frame input from the buffer or the frame input from the retransmission register described later. A transmission information addition circuit that outputs the information, a transmitter that transmits the output of the transmission information addition circuit, and an information frame that is output from the buffer and inputs one of the previously transmitted information frames to one input terminal. An exclusive OR circuit that inputs the output from the retransmission register that stores the frame obtained by exclusive ORing all parts or all bits to the input terminal of the song, and outputs the exclusive OR of both parts bit by bit. and.

A retransmission register that inputs and stores the output of the exclusive OR circuit, a receiver that receives reception responses from each receiving station, and a reception status storage circuit that checks the contents of reception responses input from the receiver and is described later. Broadcast communication characterized by comprising: a reception determination circuit that controls retransmission by comparing and updating the contents of the data; and a reception status storage circuit in which the reception status of each receiving station is written by the reception determination circuit. A transmitting device for use is obtained.

(Principle of the Invention) The present invention achieves the above object based on the principle described below.

N equal length M) strings (x(1,1).

x(2,1),-=,X(M,] ))(x(1,2)
,x(2゜2), ・-,x(M,2)),-,(x(
1, N), x (2°N), ...X (M, N)).

y(j)=x(j, 1)ex(j, 2)Φ−IBX(j
, n) (j=], 2...M) where e indicates exclusive OR.

The bit string (y(1), y(2L...y(M)) of length M formed by y(j) obtained by the operation is
We will call it an N-sum bit string. By defining each bit string as above, when any N-1 bit string among the original N bit strings is known, this N-1 bit string and the N sum bit string can be divided bit by bit. By performing exclusive OR, the remaining 901 bit strings can be obtained. I also like this principle.

After transmitting a predetermined number of information frames (let's say N), if a retransmission request is received due to erroneous reception, the transmitting station retransmits the frame for which retransmission was requested in response to the initial retransmission request. Instead, the exclusive OR of the information parts of all N information frames is retransmitted, and subsequent retransmission requests are handled in response to second or more retransmission requests from the same receiving station. Only then will the requested frame be retransmitted.

On the other hand, at each receiving station where there was one or more false receptions.

The information part of the normally received information frame is subjected to exclusive OR, and the frame obtained by exclusive ORing all the retransmitted frames is subjected to exclusive OR. If there is only one erroneously received frame, the erroneously received frame can be obtained immediately no matter which one of the N erroneously received frames there is.

If there is one or more erroneously received frames, the frames for which the transmitting station issued a retransmission request after 20 will be retransmitted as described above, and these will be combined with the exclusive OR of the normally received frames. , and all the first retransmitted exclusive OR frames are sequentially exclusive ORed, and finally the erroneously received frame for which the retransmission request was made is also removed. Obtainable,(
Embodiment) An information frame to be transmitted is transmitted through a buffer 1, a transmission information addition circuit 2, and a transmitter 3, and at the same time is inputted into an exclusive OR circuit 4. The contents of the retransmission register 5 are input from the other input of the exclusive OR circuit 4,
The exclusive OR of each bit is stored again in the retransmission register 5. While the transmitter 3 transmits a predetermined number N of information frames, the receiver 6 receives reception responses (reception confirmations or retransmission requests) from each receiving station. The received reception response is input to the reception judgment circuit 7, and if the reception response is a reception confirmation, the reception judgment circuit 7 stores the reception confirmed frame for each receiving station written in the reception state storage circuit 8. If the reception response is a retransmission request, the content of the retransmission register 5 is transmitted for the first retransmission request received for the predetermined N frames, and if the second or more from the same station When a retransmission request is received, the requested information frame is retransmitted from buffer 1. No retransmission is performed for other retransmission requests.

FIG. 2 is a schematic diagram showing an example of a receiving device that receives a signal transmitted by the transmitting device of the present invention. The information frame transmitted from the transmission station 1 is input to the reception determination circuit 10, which receives the information frame from the receiver 9.

The reception determination circuit 10 detects the received frame according to a predetermined rule.
Determine whether the frame is within the range to be received and whether there is an error. When a frame to be received is normally received, the received frame is a bar.

The signal is input to one input of the filter 11 and the exclusive OR circuit 12, and the reception state storage circuit 13 is updated. The contents of the XOR register 14 are input to the other input of the exclusive OR circuit 12, and the bit-by-bit exclusive OR is stored in the XOR register 14 again. When a frame is received that is outside the range that should be received, it is simply discarded. When a frame to be received is received in error, the reception determination circuit 10 transmits a retransmission request to the transmitting station via the transmitter 15. When the received frame is the exclusive OR of the N frames that have been transmitted up to that point, the reception judgment circuit 10 uses the reception status storage circuit 13 to determine if the received frame has not been normally received by the local station. If there is none, the frame is discarded, and if there is only one frame that is not normally received by the local station, the received frame is input to one input of the exclusive OR circuit 12 and XORed. It is exclusive-ORed with the contents of the register 14, and its output is input to the buffer 11. If there are two or more frames that are not normally received by the local station, the received frames are sent to the exclusive-OR circuit 12. is input to one input of the XOR register 14, and its output is
It is input into register 14. If the received frame is a frame requested by the own station in the second or subsequent retransmission request, the received frame is input to one input of the exclusive OR circuit 12, and the contents of the XOR register 14 and exclusive logic are input. The output is inputted into the XOR register 14.

(Effects of the Invention) According to the present invention described above, the number of retransmissions is slightly less than that of the conventional automatic retransmission control system. The effects of the present invention are most noticeable when each receiving station receives at most one frame in error and the frames are different. For example, the number of consecutively transmitted frames is N, and the number of receiving stations is M (N>
M), and M receiving stations all have different frames as 1
Suppose that you receive an error message. While the conventional method required retransmission of M frames, this method requires only one retransmission.
It is sufficient to retransmit the data once.

FIG. 2 is a block diagram illustrating an example of a device for receiving information frames transmitted by the device of the present invention.

In the figure, 1.11 is a buffer, 2 is a transmission information addition circuit, 3.35 is a transmitter, 4.12 is an exclusive OR circuit, and 5
is a retransmission register, 6.9 is a receiver, 7.10 is a reception judgment circuit + 8.13 is a reception status storage circuit, and 14 is an XO
This is the R register.

Figure 1 Octopus 2

Claims (1)

[Claims] a buffer that stores information frames to be transmitted and outputs them one frame at a time; a transmission information addition circuit that adds transmission information to an information frame input from the buffer or a frame input from a retransmission register described later; A transmitter that transmits the output of the information addition circuit and the information frame output from the above buffer are input to one input terminal, and part or all of the previously transmitted information frames (described later) are exclusively ORed bit by bit. The output from the retransmission register that stores frames is input to the other input terminal, and the exclusive OR circuit that exclusive ORs the two bits and outputs the output, and the output of the exclusive OR circuit is input. Check the stored retransmission register, the receiver that receives reception responses from each receiving station, and the contents of the reception response input from the receiver, and compare and update the contents of the reception status storage circuit described later. 1. A transmitting device for broadcast communications, comprising a reception determination circuit that controls retransmission, and a reception status storage circuit in which the reception status of each receiving station is written by the reception determination circuit.