A closed-form BER expression for band-limited DS/SSMA communications

An accurate closed-form expression of approximate average bit error rate (BER) is derived for band-limited direct-sequence spread-spectrum multiple access (DS/SSMA) communications with aperiodic random quadriphase spreading sequences and the conventional matched filter receiver. Although some closed-form BER expressions have been available, they are only for systems with chip-time-limited chip waveforms and even fail to accurately evaluate the BER for some combinations of system parameters. The proposed expression instantly evaluates the average BER for band-limited systems with arbitrary chip waveforms of interest. Monte-Carlo simulation results are also provided to show the accuracy.