Performance enhancement of multicarrier CDMA systems impaired by chip timing jitter

In this paper we deal with the effect of chip timing jitter (or chip synchronization error) in multicarrier code division multiple access (MC-CDMA) schemes. The downlink is considered in the analysis. We show that the presence of a timing error less than about 20% of the sampling period can be modelled by an equivalent additional amount of additive white Gaussian noise. This result is useful for two reasons. Firstly, we can get analytical or semi-analytical formulas for the error probability. Secondly, the effect of chip timing jitter can be mitigated by using a simple time diversity technique in combination with forward error correction coding and an ARQ scheme, as in a type-I hybrid ARQ protocol. Results are given in terms of bit error rate for a typical multipath indoor radio channel