Phase Noise Suppression in MIMO LoS Systems for High Capacity Backhauling

The ambitious capacity and pervasiveness requirements for future broadband wireless networks pose new challenges in the design of high capacity point-to-point (PtP) wireless microwave backhaul links. Multiple input multiple output (MIMO) architectures are the main solution for multiplying the wireless links capacity and their effectiveness has been already demonstrated in the PtP case, where channel propagation is dominated by the line-of-sight (LoS) component. In this paper we investigate the impact and performance of suppression methods for one of the main impairments in these systems, i.e. phase noise. In LoS-MIMO systems, the phase noise impact increases as the channel matrix leaves the orthogonality condition, in order to achieve practical antenna spacings and link distances. Here architectures for phase noise suppression based on pilots patterns are compared and discussed for the LoS-MIMO ( 2 × 2 ) system, revealing the advantages and numerical performance of the design options.