ORDER RECURSIVE LATTICE DECISION FEEDBACK EQUALIZATION FOR DIGITAL CELLULAR RADIO

摘要

A received time division multiple access (TDMA) signalhaving a time slot comprised of a plurality of symbolsincluding at least one sequence of synchronizing symbols anda plurality of data symbols is demodulated by adaptivelyfiltering the received signal to minimize inter-symbolinterference due to an effect of channel signal propagationdelay. The adaptive filtering step is performed byprocessing the received signal with a multi-stage latticedecision feedback equalizer having (M = N1 - N2) stagesfollowed by (N2 - 1) two-dimensional stages. A metric isnext formed for each of the stages in accordance with apredetermined mathematical relationship between the outputsignals of each of two stages. A plurality of the formedmetrics are next accumulated over a plurality of time slots.A number of stages are then recursively determined for thelattice decision feedback equalizer for use during the nexttime slot by comparing, to a threshold value, the differencebetween the values of two accumulated metrics.