Communication method, communication system and communication apparatus

A communication method of performing channel assignment between a transmitting station and a plurality of receiving stations, comprising:

• the transmitting station assigning a communication channel to at least one receiving station from among the plurality of receiving stations to perform successive transmission of frames with the one receiving station;
• the transmitting station receiving, from a requestor receiving-station from among the receiving stations to which the transmitting station has assigned the communication channel, a retransmission request;
• the transmitting station stopping the communication established with the requestor receiving-station;
• the transmitting station assigning the communication channel to a receiving station other than the requester receiving-station and giving a priority to the communication with that other receiving station;
• the transmitting station checking whether information relating to a quality of communication line has been received from the requestor receiving-station, and upon the information relating to the quality of communication line indicating that the quality of communication line has recovered, resuming communication with the requestor receiving-station.

A communication system that includes a transmitting station and a plurality of receiving stations, wherein the transmitting station includes a unit that assigns a communication channel to at least one receiving station from among the plurality of receiving stations to perform successive transmission of frames with the one receiving station;

• receives, from a requestor receiving-station from among the receiving stations to which the transmitting station has assigned the communication channel, a retransmission request indicating retransmission of a particular frame;
• switches the communication with the requestor receiving-station to a communication according to an SAW (Stop and Wait) scheme that is one implementation of an ARQ (Automatic Repeat request) scheme;
• retransmits the particular frame according to the SAW scheme to the requester receiving-station;
• assigns the communication channel that is assigned to the requestor receiving-station to a receiving station other that the requestor receiving-station, by making use of the fact that there is a decrease in a number of frames to be transmitted in the SAW scheme and giving a priority to the communication with that other receiving station;
• switches the communication with the requestor receiving-station to the successive transmission upon reception from the requester receiving-station of a reply signal indicative of reception of the particular frame as retransmitted without error, and gives a priority to the communication with the requestor receiving-station.

A communication system that includes a transmitting station and a plurality of receiving stations, wherein the transmitting station includes a unit that:

• assigns a communication channel to at least one receiving station from among the plurality of receiving stations to perform successive transmission of frames with the one receiving station;
• receives, from a requestor receiving-station from among the receiving stations to which the transmitting station has assigned the communication channel, a retransmission request;
• stops the communication established with the requestor receiving-station;
• assigns the communication channel to a receiving station other than the requester receiving-station and giving a priority to the communication with that other receiving station;
• checks whether information relating to a quality of communication line has been received from the requestor receiving-station, and upon the information relating to the quality of communication line indicating that the quality of communication line has recovered, resumes communication with the requestor receiving-station.

A transmitting side communication device that assigns a channel to a plurality of receiving side communication devices according to an ARQ (Automatic Repeat request) scheme, comprising a unit that:

• assigns a communication channel to at least one receiving side communication device from among the plurality of receiving side communication devices to perform successive transmission of frames with the one receiving side communication device;
• receives, from a requestor receiving side communication device from among the receiving side communication devices to which the transmitting station has assigned the communication channel, a retransmission request indicating retransmission of a particular frame;
• switches the communication with the requestor receiving side communication device to a communication according to an SAW (Stop and Wait) scheme that is one implementation of the ARQ scheme;
• retransmits the particular frame according to the SAW scheme to the requestor receiving side communication device;
• assigns the communication channel that is assigned to the requestor receiving side communication device to a receiving side communication device other that the requester receiving side communication device, by making use of the fact that there is a decrease in a number of frames to be transmitted in the SAW scheme and giving a priority to the communication with that other receiving side communication device;
• switches the communication with the requestor receiving side communication device to successive transmission upon reception from the requestor receiving side communication device of a reply signal indicative of reception of the particular frame as retransmitted without error, and gives a priority to the communication with the requestor receiving side communication device.

A transmitting side communication device that assigns a channel to a plurality of receiving side communication devices, comprising a unit that:

• assigns a communication channel to at least one receiving station from among the plurality of receiving stations to perform successive transmission of frames with the one receiving station;
• receives, from a requestor receiving-station from among the receiving stations to which the transmitting station has assigned the communication channel, a retransmission request;
• stops the communication established with the requester receiving-station;
• assigns the communication channel to a receiving station other than the requester receiving-station and gives a priority to the communication with that other receiving station;
• checks whether information relating to a quality of communication line has been received from the requester receiving-station, and upon receiving line quality information indicating that the quality of communication line has recovered, resumes communication with the requestor receiving-station.