Performance of Trellis-Coded-Modulation for a Multi-Gigabit Millimeter-Wave WPAN System in the Presence of Hardware Impairments

Abstract

This paper proposes the employment of trelliscoded-modulation (TCM) to improve error performance and/or to increase system throughput in a multi-gigabit physical layer (PHY) design for millimeter-wave 60 GHz wireless personal area network (WPAN) systems. Hardware impairments such as the 60 GHz power amplifier (PA) non-linear distortion and the 60 GHz phase-locked loop (PLL) phase noise (PN) are considered in the system design. It is found that for residential environment, in the AWGN and line-of-sight (LOS) multipath channels, TCM with hard decision Viterbi decoding is able to offer coding gain of approximately 1.5 dB, and in the non-line-of-sight (NLOS) multipath channel, approximately 1.2 dB, compared with quadrature phase shift keying (QPSK). By considering non-linear distortion in the PA, bit error rate (BER) degradation of 0.8 dB is observed in LOS channel. As for NLOS channel, the same non-linear distortion causes error floor at BER=10 5. It is also observed that a maximum of 2-times improvement of the PHY throughput can be achieved by TCM in the NLOS environment. Additional gain of 0.8 dB can be obtained in NLOS channels by employing longer decoder traceback length (TBL) of 20 instead of 10.