Time-frequency interleave frequency domain equalization in single carrier UWB system

In dense multipath channel, ultra wideband (UWB) high rate short range applications mainly face long delay and severe inter-symbol interference (ISI). Due to high rate, the spreading factor is so small that the traditional direct sequence (DS) spreading is difficult to obtain satisfactory performance. Faced with long delay and severe ISI, the length of spreading sequence and the filter length of time domain equalization (TDE) are too long to implement. With ideal synchronization and channel estimation, single carrier (SC) time-frequency interleave (TFI) frequency domain equalization (FDE) we proposed can effectively overcome the severe ISI through Matlab simulation. But we still need to design the system and frame structure with considering the feasibility and complexity of hardware implementation. So this paper proposes a SC TFI-FDE frame structure, designs the improved training sequence and channel estimation method. Permuted copies of data block are transmitted, and the SC TFI-FDE system is computationally-efficient due to the use of FFT transform. With considering practical synchronization and channel estimation, SC TFI-FDE shows 2.3dB gains over SC DS-TDE at BER of 10^-3, eliminates the error floor of convolution code, and significantly reduces the outage probability more than 50% at E_b/N₀ of 15 in severe UWB channel.