Khi máy phát hiện tối đa, khả năng là quá phức tạp, chúng ta xem xét một cấu trúc nhận đơn giản như trong hình. 8,18 [36]. Người nhận bao gồm một máy dò không gian-thời gian bộ lọc phù hợp và một ngân hàng của các bộ giải mã STTC, một cho mỗi người dùng. Giả sử những kiến thức của các ma trận kênh, | Performance of STTC in CDMA Systems 277 Figure Block diagram of the space-time matched filter receiver This is equivalent to maximizing 2Re xHAHhShr - xHAHhShSHAx. As the maximum-likelihood detector is too complex we consider a simple receiver structure as shown in Fig. 36 . The receiver consists of a space-time matched filter detector and a bank of STTC decoders one for each user. Assuming the knowledge of the channel matrices the matched filter detector generates decision statistics of the transmitted spacetime symbols for all users and all transmit antennas at a given symbol period. The matched filter is represented by an nTK X nRNc matrix HhSh. The decision statistics at the output of the detector can be represented by a complex nTK X 1 column vector given by y Hh SH r Hh Sh SHAx n MAx ny where M Hh Sh SH is the space-time correlation matrix and ny Hh Sh n is the resulting noise vector. The K i 1 k th element of the decision statistics vector y denoted by yk is simply the space-time matched filter output for the signal of the ith antenna and user k obtained by correlating each of the nR received signals with its Lp multipath spreading sequences sk i sk 2 . sk Lp weighting them by the complex conjugate of the corresponding channel coefficients h 1 h-P2 . hk Lp j 1 2 . nR and summing over the multipath indices l and receive antenna j 33 . The decision statistics for user k yk y2 . ykT are then passed to the user s STTC decoder which estimates the transmitted binary information data bk. Error Probability for The Space-Time Matched Filter Detector The space-time matched filter detector in demodulates the received signal using the knowledge of the kth user s spreading sequence timing and channel information for each transmit antenna. It does not take into account the structure of the multiple access interference MAI . The error probability for the signals of the ith antenna of the kth user conditioned on the other users data and on the .
