IS-136+ slot formation

Abstract

A system and method for demodulating slots having a mixed slot formation including differential and coherently encoded slots is disclosed. The method includes pre-phase encoding data and a predetermined sequence in a slot at a transmitter such that the encoded data and the predetermined sequence have equal reference phases from a reference symbol of a previous slot having a reference phase. Another method includes pre-phase encoding the predetermined sequence with a phase determined from a reference symbol from the previous slot at the transmitter. Yet another method includes differentially phase encoding the predetermined sequence according to IS-136A standards using a reference phase of π 4 . In another method pre-phase encoding data includes phase shifting data using one of a group of different phase angles, each of the different phase angles an integer multiple of π 2 . Also, an IS-136 compatible receiver utilizing a 8-Phase Shifting-Key (8-PSK) slot structure for downlink communications, comprises a receiver for receiving a plurality of slots having a slot structure comprising: a SYNC sequence, data bits, and a plurality of reserved bits.

Dependencies are inferred from the claim text.