Patent ID: 8094617

Claim:
A method of recognizing an available channel in order to prevent channel occupation requirements from colliding with each other when one wireless channel is shared by plural terminals in a CSMA/CA mechanism using an IEEE 802.15.4 protocol slot, in which a backoff time varies by allocating different backoff exponents (BEs) for determining a random backoff time, the method comprising: initializing, by a processor, a CW counter, as 2; determining, by the processor, if a channel is occupied; decreasing, by the processor, the CW counter by 1 when the channel is determined to be idle; re-determining, by the processor, if the channel is occupied; and determining if the CW counter is 1 when the channel is re-determined to be occupied; and wherein if the CW counter is 1, then the BE is set to a first value, and wherein if the CW counter is not 1, then the BE is set to a second value that is different than the first value.