Pilot-Free Frequency Tracking Method for Ultra-Wideband Receivers

Abstract

Abstract-This paper suggests a pilot-free frequency tracking scheme for ultra-wideband orthogonal frequency-division multiplexing (UWB-OFDM) receivers. The proposed scheme uses a frequency-domain spreaded data symbols which is provided in the current UWB-OFDM system. Based on this property, we develop an improved frequency synchronization receiver without the use of pilot symbols. The simulation results indicate that the proposed scheme achieves much better performance than the conventional pilot-based schemes.

Adaptive Turbo-Equalizer Design for Multi-User Mobile Communication Channel

“…Its soft output will be in the mathematical form as This is used in first iteration, from the second iteration on the feedback filter coefficients b l are approximated and calculated from the priori information so that x fb = 2a. The advantage we find here over a linear equalization or a zero forcing equalizer, primarily its capability to handle ISI channels with spectral nulls, but DFE [7][8][9][10] are not the optimum equalizer solutions in terms of performances. It is obvious that the simulated result of MMSE MAP sequence detectors performances is better than having higher computational complexity.…”

“…The common term takes into account that it has to be regained from the multiuser signal and all users' data could be detected parallely in the same manner. After de-interleaving & demodulation the sequencex T C,1 has to be decoded by the Turbo decoder [6][7][8][9], producing the estimation of this user's datax 1 and extrinsic information about bit probability for iterative use of the whole Turbo scheme Receiver. Fig.…”