Receivers for wireless local area networks based on the IEEE 802.11b standard are required to operate well in heavy multipath, as well as additive noise impairments. This paper discusses a practical approach to combined equalizing and decoding for IEEE 802.11b systems, based on the Fano sequential decoding algorithm. Simulation results are presented demonstrating the greatly improved performance attained using this algorithm to the performance obtained using separate equalization and decoding blocks. This method has been implemented in TI's ACX100 chip. Measured laboratory results are presented that demonstrate superior throughput results obtained from this device compared with throughputs obtained by competitive devices available on the market.

In this paper, trellis group codes are introduced as an extension of Slepian group codes to codes over sequence spaces. A trellis group code is defined over R/sup n/ as the orbit of a bi-infinite "seed sequence", x/sub 0//spl isin/(R/sup n/)/sup Z/, under an infinite, defining group of transformations. This group of transformations is generated by a symbolic system. The theory is developed by combining a nontrivial extension of the notion of an isometric labeling, with results from the theory of symbolic dynamics over groups. New results presented here include a useful characterization of uniform partitions and a symbolic dynamic classification of trellis group codes. The theory is used to develop a class of rotationally invariant, nonabelian trellis group codes for QAM modulation. It is also shown that the 8-state, rotationally invariant trellis code designed by Wei (1984), used in the V.32 (and V.32 bis) international modem standard, belongs to this class.>