The multiple input and multiple output MIMO and smart antenna SA technique have been widely accepted as promising schemes to improve the spectrum efficiency and coverage of mobile communication systems.
The denition of direction-of-arrival DOA estimation is that multiple directions of incident signals can be estimated simultaneously by some algorithms using the received data. The conventional DOA estimation of User Equipments UEs is one by one, which is named as sequential scheme. The Virtual MIMO VMIMO
scheme is that the Base Station BS estimates the DOAs of UEs in a parallel way, which adopts the SA simultaneously. Obviously, when the power is fixed, the VMIMO scheme is much more energy ecient than the sequential scheme. In VMIMO scheme, a set of UEs
are grouped together to simultaneously communicate
with the BS on a given Resource Block RB Then the BS using multiple antennas can estimate the 2DDOA of the UEs in the group simultaneously. Based on
VMIMO system, the 2DDOA estimation algorithm for uncorrelated and coherent signals is proposed in this paper. The special structure of mutual coupling matrix MCM of uniform linear array ULA is applied to eliminate the eect of mutual coupling. The 2DDOA of
uncorrelated signals can be estimated by DOAmatrix
method. The parameter pairing between azimuth and elevation is accomplished. Then these estimations are utilized to get the mutual coupling coecients. Based on spatial smoothing and DOA matrix method, the 2D-DOA of coherent signals can be estimated. The CramerRao lower bound CRB is derived at last. Simulation results demonstrate the eectiveness and performance of the proposed algorithm.
Keywords VMIMO system DOA estimation multipath mutual coupling