Capacity Analysis of Millimeter-Wave Fading Interference Channels with Beam Misalignment

Ergodic capacity of a point-to-point millimeter-wave (mmWave) communication link is significantly influenced by antenna gain. In this paper, the joint impact of beam misalignment, multi-user interference and small signal fading on the achievable capacity of mmWave beamformed point-to-point links is analyzed. The angular spread of rays constituting the non-line-of-sight mmWave multi-path cluster is accounted for while deriving the expression for achievable spectral efficiency (SE) of such links. The evaluation provides accurate bounds on achievable capacity due to the consideration of clustering phenomenon which is peculiar to millimeter wave signal propagation. Numerical evaluation reveals the dependence of achievable SE on the extent of beam misalignment, angular spread of multi-path rays and the number of interfering users, thus providing useful insights into the design of beamforming and beam tracking schemes for next generation wireless communication systems.