Adaptive coded modulation for mobility constrained indoor wireless environments

The performance of rate adaptive trellis-coded and uncoded M-ary quadrature amplitude modulation (M-QAM) over large open office indoor wireless environments is studied in this paper. An appropriate composite fading/shadowing channel model termed the joint fading and two-path shadowing (JFTS) model is adopted for such an indoor wireless environment, where mobility of users remains constrained within a small space. Mathematically tractable expressions for the spectral efficiency and average bit error rate (ABER) of adaptive coded and uncoded M-QAM over the JFTS channel are derived. Numerical results demonstrate that in contrast to conventional fading models like Rayleigh and Nakagami-m distributions, the error probability performance of rate adaptive M-QAM over a JFTS faded/shadowed link never approaches zero for lower channel signal-to-noise ratios (CSNRs).