Efficient OFDM Reference Signal Design for Multi-Layer Transmission

In this paper, we newly design a reference signal in OFDM based multi-layer transmission. Among the all reference signals, some of them on different transmit layers are partially overlapped, who are occupying the same resource element. In the receiver, an iterative estimation mechanism is considered to gradually filter and precisely separate the overlapped reference signals relying on non-overlapped (orthogonal) reference signals, by means of, for instance, two-dimensional linear filter. As a consequence, the total number of resource elements dedicated to reference signal is condensed by a factor of at least quarter, only suffering somewhat negligible performance degradation.