Robust transmission scheduling and power control for dynamic wireless access in a hospital environment

We propose a robust optimization framework for the multiple-access problem in a hospital environment. The users of e-Health applications (referred to as secondary users) coexist with active and passive medical devices (referred to as primary and protected users, respectively) under uncertainty in the channel (i.e. propagation) conditions. In particular, we design robust transmission scheduling and power control methods for secondary users in multiple spatial reuse time-division multiple access (STDMA) networks. The objective of the optimization framework is to maximize the spectrum utilization of secondary users and minimize their power consumption subject to the electromagnetic interference constraints for primary and protected users. In this framework, we model the channel uncertainty as ellipsoidal uncertainty sets and the transmission scheduling and power control are optimized taking this uncertainty into account. Numerical results show that the proposed framework can achieve robust scheduling and power control against channel variations. By adjusting the robustness parameter (i.e. the degree of conservatism), we can balance the tradeoff between robustness and spectrum utilization.