On symbol timing recovery in all-digital receivers

摘要

Sandia National laboratories (SNL) currently achieves a bandwith efficiency ( eta ) of 0.5 to 1.0 bps/Hz by using traditional modulation schemes, such as, BPSK and QFSK. SNL has an interest in increasing the present bandwidth efficiency by a factor of 4 or higher with the same allocated bandwidth (about 10 MHz). Simulations have shown that 32-QAM trellis-coded modulation (TCM) gives a good bit error rate (BER) performance, and meets the requirements as far as the bandwidth efficiency is concerned. Critical to achieving this is that the reciever be able to achieve timing synchronization. This paper examines a particular timing recovery algorithm for all-digital receivers.