Efficient Integer Frequency Offset Estimation Architecture for Enhanced OFDM Synchronization
Pham, Thinh Hung
Fahmy, Suhaib A
McLoughlin, Ian Vince
- Publisher: IEEE
An integer frequency offset (IFO), in orthogonal\ud frequency-division multiplexing (OFDM) systems, causes a circular\ud shift of the sub-carrier indices in the frequency domain.IFO\ud can be mitigated through strict RF front-end design but this\ud is challenging and expensive. Therefore, IFO is estimated and\ud removed at baseband, allowing the RF front-end specification\ud to be relaxed, thus reducing system cost. For applications\ud susceptible to Doppler shift, and multi-standard radios requiring\ud wide frequency range access, careful RF design may be\ud insufficient without IFO estimation. This paper proposes a novel\ud approach for IFO estimation with reduced power consumption\ud and computational cost. A four-fold resource sharing architecture\ud reduces computational cost, while a multiplierless technique and\ud carefully optimised wordlengths yield further power reduction\ud while maintaining a good accuracy. The novel method is shown\ud to achieve excellent performance, similar to the theoretically\ud achievable bound. In fact, performance is significantly better\ud than conventional techniques, while being much more efficient.\ud When implemented for IEEE 802.16-2009, the proposed method\ud saves 78% power over the conventional technique on low-power\ud FPGA devices. The method is applicable to IEEE 802.11 and\ud IEEE 802.22.