| 摘要 |
A receiver decodes unknown information symbols interlaced with known information symbols transmitted using a signal modulated either with Gaussian Minimum Shift Keying (GMSK) or alternatively with Offset 16-Quadrature Amplitude Modulation (O-16QAM) and compensates for inter-symbol interference caused by a multipath propagation delay. The receiver comprises a state memory (14) for storing a plurality of states, each state comprising a decoded value string and associated path metric. Each decoded value string corresponds to different hypotheses of information contained in signal samples already processed, and each of the associated path metrics is indicative of a likelihood that the corresponding hypothesis was a correct hypothesis. The receiver also comprises a channel estimator (11) for estimating channel coefficients indicative of the phase and amplitude of each path of the multipath propagation based on received signal samples that correspond to the known information symbols. A detector detects whether the known information symbols were transmitted using GMSK or O-16QAM modulation, and produces an equaliser mode indication signal. A Viterbi processor (20) controls the processing of each successive signal sample to update each state of the state memory (14) by extending the decoded value string and updating the associated path metric, each updated state being derived from one or four previous states when the equaliser mode indication signal is indicative of O-16QAM, and alternatively derived from one of two previous states when the equaliser mode indication signal is indicative of GMSK. <IMAGE> |
