This article presents downlink initial synchronization and cell identification algorithms for long term evolution (LTE) of third-generation (3G) mobile communication systems, which are based on synchronization channel (SCH) and cell specific pilot symbols, respectively. The key features of the proposed scheme are: it can improve performance of the frequency synchronization through oversampling of the SCH, it can support a large number of target cells by modulating a cell-specific pilot sequence over two symbols within a subframe, and it can guarantee cell identification performance by maximally ratio combining the frequency domain differential cross-correlation. Simulations show that the proposed scheme has a potential use in 3G LTE.
The Wide-Sense Stationary Uncorrelated Scattering (WSSUS) model has long been viewed as a basic channel model to describe the fading dispersive channel. But non-WSSUS models have more universal applicability when the wireless mobile channel with broadband is studied with finer and more detailed knowledge of propagation environments. So the four-Dimension (4-D) characteristics of channel, namely time, lag, frequency, and Doppler, should be studied together. In this paper, Wigner-Ville distribution of Time-Frequency (TF) domain is introduced to analyze channel in which the incidence rays are non-stationary and correlated with each other. Several channel models, according to different move modes of incidence rays, with time-varying Doppler shift are designed and 4-D Local Scattering Function (LSF) are computed and simulated respectively. Our simulation results show the LSF present asymmetric and non-periodic TF distribution for some symmetric and periodic move modes of incidence rays.
