1 Outage in Chaos Communication

The paper investigates the notion of outage, as an assessment of the likelihood of a bit being in error, for chaos-based communication systems. It is seen as a complementary measure of performance to bit error rate. For antipodal chaos shift keying (CSK) a theoretically exact formula is derived which is then used in specific cases to obtain useful qualitative and quantitative information. Illustrations are with independent Gaussian spreading as an upper benchmark and with the logistic map spreading as typical of effective chaos; a uniform spreading distribution is also used. Comparisons are obtained between these spreading distributions and between different extents of their spreading, calibrated against per bit signal to noise ratio. The distribution of bit error probability over spreading sequences is also obtained, being the fundamental quantity for both outage and bit error rate. The form of this distribution illustrates the degree to which bit error rate is a stable representation of performance.