Low complexity frequency offset estimation in the presence of DC offset

This paper describes how to perform a low complexity frequency offset estimation in the presence of direct current (DC) offset based on a received periodic preamble. By designing a suitable preamble, we perform frequency and DC offsets estimation concurrently, followed by a simple compensator which reduces the frequency offset error induced by the presence of either a residual or actual DC offset. Its performance is illustrated based on the preamble of wireless LAN system defined in IEEE 802.11a, as well as another preamble design that offers additional performance gain. Compared to the case when no compensator is used, the proposed solution gives superior performance over a wide range of dc offset power in both AWGN and multipath quasi-static channels.