Aditya Wadaskar, Shamik Sarkar, Danijela Cabric


Millimeter wave (mmWave) cellular networks are characterized by dense deployments of base stations and users. Identifying spectrum-sharing opportunities in these bands is
of crucial importance to ensure optimal spectrum utilization. However, non-cooperating cellular operators sharing spectral resources suffer from capacity degradation due to wideband interference. Without explicit channel knowledge and coordination across operators, interference suppression with the analog phased antenna arrays deployed by the mmWave antenna front end is difficult. In this context, this paper proposes a low-complexity and low-latency wideband nulling solution using analog True-Time-Delay arrays to facilitate spectrum sharing between operators. The proposed method does not require explicit channel estimation and strict coordination between operators and exploits the spatial
degrees of freedom to achieve the desired beamforming and null steering, based on the estimated Angles of Arrival (AoA) of the incoming signals. We also present simulation results to demonstrate the interference suppression capabilities of the proposed algorithm, and provide comparison with digital array-based algorithms.