Oversampled CI-OFDM Baseband Transceiver Architecture and Its FPGA Prototype

Abstract

Orthogonal frequency division multiplexing (OFDM) scheme has been widely employed in the wireless communication systems. However, the scheme suffers a limitation of high peak to average power ratio (PAPR). Carrier Interferometry (CI) codes proved to be an efficient PAPR reduction method but these CI codes when employed with OFDM (CI-OFDM), acts as a single-carrier modulation scheme. To retain the principle of multi-carrier modulation and gain the advantage of low PAPR using CI codes, a new efficient oversampled CI-OFDM scheme is proposed in this paper. Furthermore, the architecture for the oversampled CI-OFDM transceiver with two modulation schemes is proposed and prototyped on the commercially available virtex5 FPGA device in the laboratory experimental setup. The proposed scheme exhibits a PAPR reduction of minimum 4 dB, and a bit error rate (BER) of is achieved for a signal to noise ratio (SNR) of 8.4 dB. To analyse the behaviour of the proposed scheme, various hardware performance parameters in terms of occupied bandwidth, channel power of main lobes and side lobes are measured, and the total bandwidth is found to be 240 KHz. The hardware resource utilization of the proposed architecture is also reported.