Multiple access cellular communication with circular interleaving and reduced dropped-packet runlengths

摘要

An apparatus and method for reducing the runlength of dropped packets in multiple access cellular communication systems. The invention is particularly well suited for use in time-division multiple access (TDMA) systems such as, for example, shared time-division duplexing (STDD) systems, and TDMA/TDD systems with speech activity detection (SAD). Frame time or frequency slots for communicating information are allocated to a first set of active users. A second set of active users which are not allocated a slot in a given frame are identified. At least one of the users in the second set which remains active in a subsequent frame is provided with a priority in obtaining an allocated slot in the subsequent frame. In one embodiment, the slots allocated to particular active users in the given frame are shifted by at least one slot position if the same users are allocated slots in the subsequent frame. The priority allocation and slot position shifting may be implemented by circular interleaving of the first set of users which have been allocated slots in the given frame with the second set of users which remain active but were not allocated slots in the given frame. The circular interleaving may be utilized with fast speech activity detection (FSAD) in order to further reduce dropped-packet runlengths.