Joint Transmission Reception Point Selection and Resource Allocation for Energy-Efficient Millimeter-Wave Communications

In this paper, we study the joint transmission reception point (TRP) selection and resource allocation problem to maximize the weighted sum energy efficiency under imperfect channel state information (CSI) for an uplink mmWave network considering beam training overheads and delay constraints with and without inter-beam interference, respectively. First, to guarantee the delay constraints of all UEs, we use the worst-case approach to cast the considered problem to a deterministic optimization problem. Then, for the scenario without inter-beam interference, the product of transmitting and receiving beams and the power allocation scheme for each pair of UEs and TRPs are derived iteratively, where the former is obtained by some relaxation operations under given power allocation policy, and the latter is searched by bisection under given beamwidth selection policy. After that, Kuhn-Munkres algorithm is used to find the joint TRP selection and resource allocation policy. For the scenario with inter-beam interference, coalition game is proposed to solve the considered problem, where UEs form coalitions to select their respective serving TRPs. At each iteration of the coalition game, the beamwidth control and power allocation are performed successively, where the transmitting and receiving beamwidths are solved by particle swarm algorithm under given power allocation policy, and the power allocation strategy is designed by a novel cooperative cost mechanism under given beamwidth selection policy. Finally, extensive simulation results are provided to verify that the proposed schemes achieve better weighted sum energy efficiency than existing schemes.