Sierra Wireless, Inc.
Methods and apparatuses for phase rotation in 2 sub-carrier PI/2 binary phase shift keying communication

Abstract:

The present invention provides methods and apparatuses for implementation of cyclic prefix (CP) and demodulation reference signal (DMRS) in 2 sub-carrier pi/2 binary phase shift keying (BPSK) modulation in a communication system. DMRS symbols are interleaved with data-carrying symbols and configured such that they are alternatingly transmitted on different ones of the two sub-carriers. When a DMRS symbol is transmitted on one sub-carrier, the other sub-carrier may be unused. In implementing CP, phase rotations may be applied to modulation symbols, such that each concurrently transmitted pair of symbols is subjected to a same phase rotation. The phase rotation can be derived based on an average frequency of the two (e.g. adjacent) sub-carriers in use. The phase rotations can be updated recursively, and the update multiplied by a scaling factor.