Blind uplink channel and DOA estimator for space-time block coded MC-CDMA system with uniform linear array

Space-time coded multi-carrier code division multiple access (MC-CDMA) is studied in this paper. For macrocellular systems with the frequency-selective fading, we propose a scheme including a uniform linear array (ULA) at the base station, a Tarokh space-time block code (STBC) at every user side, and using only one spreading code for each user. Moreover, its blind channel identification and Directions-Of-Arrival (DOA) estimation algorithm is proposed also and includes two steps: first, by dividing the ULA into two identical overlapping subarrays, we construct a specific auxiliary matrix including both uplink channels and DOAs information of all active users. DOAs can be estimated and the users with different impinging DOAs are separated via an ESPRIT-like algorithm; second, a joint space-frequency uplink vector channel impulse response (VCIR) identification algorithm is developed for all active users within one macrocell by exploiting the structure of the STBC and the singular value decomposition. Finally the closed-form solution of the uplink VCIRs and DOAs for all active users can be obtained. Computer simulation results demonstrate the validity of this proposed scheme.