Acquisition of an Unknown Hopping Code in an Ultra-Wideband FH-OFDM System

In this paper, we study methods for code acquisition in a burst-type ultra-wideband (UWB) frequency-hopped (FH) orthogonal frequency division multiplexing (OFDM) system. In the first scenario, the time-frequency code (TFC) that controls the frequency-hopping is assumed to be completely unknown to the receiver, while in the other scenario we make simplifying assumptions with regard to the TFC. Data-aided (DA) decision variable generation method is used, which aims at keeping the acquisition time and training data overhead to a minimum. Parallel and serial receiver algorithms are proposed for the scenarios, and an iterative serial method for acquiring the TFC is developed. While the parallel receiver enables fast detection, in some cases it is unfeasible due to its complexity. The receiver using the low-complexity serial approach needs more information about the TFC to ensure efficient operation. Simulation results prove that it achieves good performance when such conditions exist.