Synchronization sensitivity of multicarrier systems

In this paper, we give an overview of the sensitivity of a number of multicarrier systems to carrier and clock synchronization errors. A comparison is made between orthogonal frequency division multiplexing/multiple access (OFDM(A)) and two combinations of the orthogonal multicarrier technique and the code-division multiple access (CDMA) technique, i.e., multicarrier CDMA (MC-CDMA), where the spreading is accomplished in the frequency domain, and multicarrier direct-sequence CDMA (MC-DS-CDMA), where the spreading is done in the time domain. We evaluate the effect of small synchronization errors on the BER performance by deriving simple analytical expressions for the BER degradation that are based upon truncated Taylor series expansions. To allow a fair comparison, all considered systems are able to accommodate the same number of users, and each user operates at the same data rate. Under these conditions, we show that all multicarrier systems exhibit the same sensitivity to carrier phase jitter and timing jitter. Further, when the number of carriers is equal to the maximum number of users, the different multicarrier systems also are equally affected by a carrier frequency offset or a clock frequency offset. 2 I