Abhishek K. Gupta, Ahmed Alkhateeb, Jeffrey G. Andrews and Robert W. Heath, Jr.
To appear in Proc. of GLOBECOM 2016.
Sharing the spectrum among multiple operators seems promising in millimeter wave (mmWave) systems. This is mainly due to the highly directional transmission in mmWave, which reduces the interference caused by one network on the other networks sharing the resources. While uncoordinated sharing is better than orthodox allocation, allowing static network coordination based on large channel statistics may further improve network performance. In this paper, we model a mmWave cellular system where an operator owns an exclusive-use license of a certain band with a provision to sell a restrictive secondary license of the same band to another operator. This secondary license has a restriction on the maximum interference each of its base stations can cause to any nearby user of the original network. Using stochastic geometry, we derive expressions for the coverage and rate of both networks, and establish the feasibility of secondary licensing in licensed mmWave bands. Results show that the restricted secondary operator can achieve good coverage with a small impact on the original operator. Results also illustrate that these spectrum sharing gains increase when narrow beams and dense networks are deployed.