Design and implementation of UWB systems with timing synchronization in MATLAB Simulink

Abstract

Ultra wide band (UWB) bandwidth is much higher than the system bandwidth requirement. Due to large bandwidth in UWB, its systems must have time resolution for system time distribution. But we need to improve data rate and efficiency of the system which uses ultra wide band channels as data rate may trade for power spectral density and performance in multipath. In order to increase data rate, here in this project the orthogonal frequency division multiplexing (OFDM) system is used. But we need to overcome the drawbacks in OFDM like peak to average power ratio (PAPR) (5), carrier frequency offset (CFO), inter symbol interference (ISI), inter carrier interference (ICI). In order to control the effect of PAPR and CFE the single carrier with frequency domain equalization (SC-FDE) can be used, as it has lower PAPR and lower sensitivity to CFO compared to OFDM but the problem is that it is less robust to timing error. As the data rate in UWB systems is high, there is heavy requirement of accuracy in timing synchronization constraints. Moreover the high dispersive nature of UWB channels is an extra challenge to acquire timing synchronization. In general, synchronization can be done based on auto correlation and cross correlation methods. Joint timing and channel estimation (JTCE) can also be done but the computational complexity while correlating will be more compared to correlation methods. But, for UWB systems the timing schemes cannot perform well as multi path UWB channels are denser and longer than wideband channels. Due to trade off's and computational complexity the implementation of large size Fast Fourier transform (FFT) and Inverse FFT (IFFT) can't be employed. In this paper, we discuss the design and implementation of UWB systems with timing synchronization by avoiding all the above discussed PAPR, CFO, ISI, ICI and timing synchronization in UWB channel problems and results are compared by transmitting signal through three different channels (dispersive, fading and addictive white Gaussian noise (AWGN) channels).