Patent ID: 7403892

Claim:
A method of controlling the operation of an Adaptive Multi-Rate encoder for encoding speech signals to be sent between a first node and a second node in a wireless communication system, the encoder being operable to encode the speech signals in at least two modes having different degrees of robustness, the method comprising the steps of: sensing a first communication condition in a communication channel between the first and the second node; identifying a first mode applicable to said encoder corresponding to the first communication condition in the communication channel; storing a value indicative of the first mode in a memory, the length M of which is selected responsive to an Adaptive Multi-Rate loop delay, where M is an integer; and comparing the value indicative of the first mode to a plurality of values previously stored in the memory, each of said plurality of values being indicative of one of a set of previous modes corresponding to one of a plurality of previously sensed communication conditions wherein, compared to the plurality of previously stored values, if the value indicative of the first mode indicates that the first communication condition is degraded relative to the plurality of previously sensed communication conditions, selecting said first mode as a selected mode to be applied by said encoder; or is improved over at least one of the plurality of previously sensed communication conditions, selecting one of said previous modes as the selected mode to be applied by said encoder.