An Efficient Frequency Offset Estimation Scheme for Multi-Band OFDM Ultra-Wideband Systems

A frequency offset estimation scheme is presented for coarse frequency offset estimation of Ultra-Wideband (UWB) Multi-Band Orthogonal Frequency Division Multiplexing (MB- OFDM) systems. Cramer Rao Lower Bound (CRLB) for variance of the estimated frequency offset is derived and compared with the simulated results of the proposed scheme. Performance of the MB-OFDM system in terms of the Bit Error Rate (BER) with suggested frequency offset estimator is also reported. The algorithm is tested by computer simulation over multiple UWB channel models (CM), CM1: 0-4m line-of-sight, CM2: 0-4m non-line-of-sight (NLOS), CM3: 4-10m NLOS, and CM4: 25 nsec. delay spread as suggested by IEEE 802.15 Channel Modeling sub-committee. With higher number of iteration the algorithm shows improvement of the system performance by 8.8 dB in both CM1 and CM2; 7.6 dB for CM3 and 8.3 dB for CM4 at BER=10^-4.