| 主权项 |
1. An initial synchronization apparatus for receiving a received signal comprising a training sequence, the initial synchronization apparatus comprising:
an over-sampling unit, sampling the received signal to obtain N over-sampling signals; a receiving buffer, which is coupled to the over-sampling unit, has N storage units, and stores the 0th˜(N−1)th over-sampling signals; a channel estimation unit, which is coupled to the receiving buffer and performs a channel estimation on the over-sampling signals according to a local training sequence to obtain D channel tap-weighting coefficients, wherein the local training sequence comprises D discrete training signals represented as s[0], s[1], . . . , s[D−1]; D matched filter operating units, each matched filter operating unit having D input terminals, wherein the Jth input terminal of each of the matched filter operating units receives the over-sampling signal of the (MT×J)th receiving buffer, wherein a matched filtering operation is performed on the over-sampling signal of the Kth input terminal of the (m′)th matched filter operating unit and a conjugate of the discrete training signal s[MOD(K−m′)] to obtain a Kth matched operation result, wherein the (m′)th matched filter operating unit combines all the matched operation results into a (m′)th filter signal, where MOD(x) represents a remainder obtained after x is divided by D; a time maximum ratio combining unit, which is coupled to the D matched filter operating units and the channel estimation unit, and performs a weight-product operation on the Ith filter signal and a conjugate of the Ith channel tap-weighting coefficient to obtain an Ith time tap-weighting coefficient result, wherein the time maximum ratio combining unit combines all the time tap-weighting coefficient results into a time combining signal, wherein every predetermined time, the receiving buffer replaces data of the Mth storage unit with data of the (M−1)th storage unit, and updates the first storage unit, and every predetermined time, a new time combining signal is generated, wherein the Qth time combining signal is generated in the Qth predetermined time; and a time decision unit, which is coupled to the time maximum ratio combining unit, collects R time combining signals, performs a maximum estimation on the R time combining signals, finds out a maximum time combining signal, and extracts a time index corresponding to the maximum time combining signal as a timing error estimation value; where D, N, and MT are positive integers, N≧MT×D, J, K, m′, I are integers ranging from 0 to D−1, M is a positive integer, 2≦M≦N, R is a positive integer, and Q is a real number. |
