Correlation based-Frequency offset estimation Over UWB Channels in Wireless Networks

The demand for seamless mobile connectivity and wireless internet access across the globe has been increasing. OFDM has been shown to be very efficient in wireless and wire line communication over broadband channels. Frequency offset is mismatch between transmitter frequency and receiver frequency. Frequency offset is produced by unstable receiver clock generator or Doppler Effect. OFDM systems are very sensitive to these frequency offsets. The sensitivity is increased by increasing the number of sub carriers or constellation. Frequency offset degrades the performance of both channel estimation and symbol detection. Ultra-Wide Band (UWB) systems (e.g., impulse radios and transmitted reference schemes to name a few) offer improved ranging precision, better penetration through obstacles, higher data rate, and increased multipath or frequency diversity. By applying auto correlation or cross correlation techniques, the frequency offset of OFDM based UWB channels can be estimated. Index Terms – OFDM, UWB, Frequency offset, BER