METHOD FOR RECOGNIZING AVAILABLE CHANNEL IN IEEE 802.15.4 PROTOCOL

摘要

The present invention relates to a method for checking a channel occupancy state under a protocol CSMA / CA scheme of IEEE 802.15.4. In the present invention, a plurality of terminals share one wireless channel under a protocol slot using CSMA / CA scheme of IEEE 802.15.4 protocol. A method of checking the occupancy state of a channel so that channel occupancy requests do not collide with each other, the first step of initializing a counter (CW) used for a CCA attempting before transmitting a frame to 2 and a channel to be used. A second step of determining whether the channel is occupied, a third step of decreasing CW by one if the channel is not occupied in the second step, and a fourth step and a fourth step of determining again whether the channel is occupied As a result of the determination that the channel is occupied, the fifth step of determining whether or not the CW has a value of '1' by including the first CCA fails and the second CCA In case of failure, the channel occupancy status is checked under the protocol CSMA / CA method of IEEE 802.15.4, characterized by differently assigning backoff exponents (BE) to determine a random backoff time. The method is presented.;IEEE 802.15.4; slotted CSMA / CA