Sharing Spectrum Licenses in mmWave Cellular Systems

Due to scarcity of spectrum at conventional cellular frequencies (CCF), the use of higher frequencies such as mmWave has been proposed for 5G cellular networks. The cellular systems consist of multiple networks, each deployed by an independent cellular operator with possibly closed access only to its customers. It is worth noting that communication at mmWave frequencies has non-trivial differences when compared to communication at CCF. This leads to the possibility of a new kind of sharing called spectrum license sharing, where independent cellular operators who own licenses for separate frequency bands agree to share the complete rights of operation in each other’s bands without any explicit coordination. Sharing licenses may allow all networks to use the full spectrum simultaneously without impacting the individual achieved rates and helps operators reduce their expenses by sharing license costs.

WNCG graduate student Abhishek Gupta and WNCG Professors Jeffrey G. Andrews and Robert W. Heath Jr. have established the theoretical feasibility of spectrum license sharing among mmWave cellular operators. They present a tractable model for a multi-operator system containing multiple independent cellular networks, each owned by an operator. They compute the performance in terms of the SINR and rate distribution for downlink mobile users of each network. Using the analysis, they compare systems with fully shared licenses and exclusive licenses for different access rules and explore the trade-offs between system performance and spectrum cost. They show that sharing spectrum licenses increases the per-user rate when antennas have narrow beams and is favored when there is a low density of users. They also consider a multi-operator system where BSs of all the networks are co-located to show that the simultaneous sharing of spectrum and infrastructure is also feasible. 

Relevant Papers:

A. K. Gupta, J. G. Andrews, and R. W. Heath Jr, “On the feasibility of sharing spectrum licenses in mmWave cellular systems,” Submitted to IEEE Trans. Commun., available at http://arxiv.org/abs/1512.01290.

A. K. Gupta, J. G. Andrews, and R. W. Heath Jr, “Can operators simply share millimeter wave spectrum licenses?” in Proc. ITA, San Diego, CA, Feb. 2016. Available at http://ita.ucsd.edu/workshop/16/files/paper/paper_323.pdf