Patent ID: 7570656
Filing Date: 2009-08-04
Classification: H04B,H04L,H04W

Abstract:
1. A method of accessing a channel in a communication transceiver coupled to a communications channel, the transceiver adapted to provide carrier sense signals including a fast carrier detect (FCD) signal to predict the early start of transmission on said channel and having a high false alarm rate and a carrier detect (CD) signal having a low false alarm rate and indicating that a transmission is starting, said method comprising the steps of: establishing a channel contention period divided into a plurality of time slots, the width of each time slot substantially equal to the time of said FCD signal; initializing a backoff counter with a backoff count equal to a random number of time slots; decrementing said backoff counter while said medium is idle; suspending said backoff counter upon receipt of a FCD signal; resuming decrementing said backoff counter upon failure of a CD signal to arrive within a CD time, said CD time proportional to a time period during which the arrival of a CD signal is expected in the event a transmission is received; deferring transmission until a next contention period upon receipt of a CD signal; and starting transmission upon expiration of said backoff counter.