Open-loop unitary precoding for parallel interference cancellation in MIMO systems

In this paper, we propose open-loop unitary pre ceding for a parallel interference cancellation (PIC) named zero forcing unitary-precoded PIC (ZF-UPIC). This technique consists of three parts: zero-forcing equalization with unitary decoding, PIC, and maximal ratio combining. At the transmitter, symbols are multiplied by a predefined unitary vector in precoding process, and then, the preceded signals are combined upto the number of transmit antennas. At the receiver, the symbols can be decoded in parallel by means of the property of unitary vectors, which enables to cancel perfectly the co-channel interference. Simulation results confirm that the proposed method yields an equivalent performance to ordered successive interference cancellation methods, while maintaining the computational complexity comparable to those of linear detection algorithms.