Frequency-Hopped Spread-Spectrum Systems Have a Larger Multiple-Access Capability: The Effect of Interfering Signals with Unequal Power Levels

摘要

In this report we present a new method for the evaluation of the probability of error of uncoded frequency-hopped spread-spectrum multiple-access (FH/SSMA) communications. For systems with binary FSK modulation, the method provides an accurate approximation and a tight upper bound to the bit error probability; for systems with M -ary FSK modulation, it provides tight upper bounds to the symbol error probability. This method relies on the integration of the product of the characteristic function of the envelope of the branch of the BFSK demodulator, which carries the desired signal, and of the derivative of the characteristic function of the envelope of the other branch; it can achieve any desirable accuracy and the computational effort required for its evaluation grows linearly with the number of interfering users. In the M -ary case, tight upper bounds based on the union bound and the results of the binary case are derived. Keywords: Frequency hopping, Spread spectrum, Multiple access, and Error control coding. (RH)