CONGESTION CONTROL IN A COMMUNICATION NETWORK BASED ON THE CSMA/CA PROTOCOL

摘要

The present invention relates to a congestion control method for a communication system supporting layered radio channel structure for communication between at least a first communication device and a second communication device, the layered structure comprising at least a physical layer and a medium access layer. The communication system is arranged to offer a first type of service with a first priority order and a second type of service with a second priority order, in the communication system messages comprising a preamble and a payload can be transmitted between devices, each message being separated by at least a period corresponding to a minimum allowable period between two messages. In the method the first communication device first (a) generates (301) a physical layer message pertaining to the first type of service; (b) senses (303) the radio channel idle for at least a period corresponding to the minimum allowable period between two messages; and (c) transmits (305) the physical layer message comprising a special preamble indicative of the type of service the message pertains, wherein the content of the preamble is arranged to be detected by the second communication device within a communication range irrespective of the decoding state of the payload of the transmitted message.