Performance and parameter optimization of RAKE reception with interchip interference

In this paper, performance and parameter optimization of RAKE reception for time-hopping ultra wideband (TH-UWB) systems is investigated when interchip interference (ICI) is taken into consideration. For a TH-UWB system, ICI is closely related to the relationship between the number of chips in a frame (N_c), and the period of the TH code (N_f). In a fixed data-rate case, larger N_f implies higher transmitted symbol signal-to-noise ratio (SNR) and larger ICI in RAKE fingers. So there is a tradeoff between N_c and N_f to optimize the RAKE performance. In this paper, two models are suggested to describe the ICI, and this tradeoff is investigated in the single user case based on the traditional Gaussian approximation method and other flexible methods. Given the lack of explicit knowledge of the relationship among N_f, N_c and the interference, a rule of thumb is proposed to configure N_f and N_c.