Timing Recovery Using Soft Information Feedback and Efficiency of Array Codes

of the Dissertation Timing Recovery Using Soft Information Feedback and Efficiency of Array Codes by Esteban Luis Vallés Doctor of Philosophy in Electrical Engineering University of California, Los Angeles, 2007 Professor John D. Villasenor, Co-Chair Professor Richard D. Wesel, Co-Chair The main contribution of the thesis provides techniques for symbol frequency and phase tracking in a pilotless Low-Density Parity-Check (LDPC) coded transmission over an AWGN channel. In traditional receiver architectures, symbol acquisition and tracking are performed using phase-lock techniques that are independent of the channel-code decoding process. In burst reception scenarios, bandwidth inefficient piloting must often be embedded in a transmission in order to accelerate acquisition to aid symbol time tracking at low signal-to-noise ratios (SNRs). In this thesis we show that outputs from the constraint node side of a bi-partite decoding graph can be used to improve the estimation of symbol frequency and phase. We focus on the problem of a symbol frequency and/or timing offset between transmitter and receiver and describe a method capable of handling very large offsets with