Modulation and coding for land mobile satellite channels

A summary is presented of the various modulation and coding techniques that have been investigated for 2.4/4.8-kb/s 5-kHz-spaced, land mobile satellite (LMS) channels. Two detection schemes are described which have many inherent advantages due to their common feed-forward processing structure. These are differentially coherent and pilot-aided detection. Based on the channel throughput and bit error rate (BER) performance requirements, i.e. 4.8 kb/s and 10/sup -3/ BER at 11 dB E/sub b//N/sub 0/, it is shown that rate-2/3, eight-phase-shift-keying (8PSK), trellis-coded modulation (TCM) with data symbol interleaving is the preferred modulation type. The receiver is implemented using differential detection augmented with feed-forward Doppler estimation. >