A Systematic Design Approach to the Band-Tracking Packet Detector in OFDM-Based Ultrawideband Systems

Multiband orthogonal frequency-division multiplexing (MB-OFDM) systems employ a frequency-hopping technology to achieve the capabilities of multiple access and frequency diversity. However, they also complicate the packet detector (PD) and time-frequency code synchronization in terms of the requirement for fast synchronization of frequency hopping, extremely low receiver sensitivity, and high hardware complexity. In this paper, we first systematically analyze the differences between MB-O-DM and conventional OFDM systems and then propose a band-tracking PD (BT-PD) that can cope with a worse-case multipath channel signal-to-noise ratio of -8.4 dB with a packet detection error rate of less than 10^-5. We also propose several low-cost design schemes for the BT-PD, such as Walsh-Hadamard decomposition, buffered-summation, and sign-bit-remaining methods. The estimated gate count of the resulting implemented BT-PD is less than half that of the existing solutions.