Improved Bit-Error Analysis for Time-Hopping Spread-Spectrum Impulse Radio Systems

This paper develops an improved and generalized analytical model for time-hopping ultra-wideband (UWB) systems. In particular, the important effects of multiple access, multipath channels, and imperfect power control are incorporated in the analysis, whereas in prior work they were often neglected. Bit-error probability is derived for two different modulation schemes: time-hopping spread-spectrum with pulse position modulation (TH-PPM) and time-hopping spread-spectrum with binary phase shift keying (TH-BPSK). Invariant of the channel model, number of users, or power control error, it is found that binary antipodal modulation has superior performance to PPM. The developed model and analytical framework is quite general and can be adapted to the analysis of future impulse radio piconet systems.