Resource Allocation in OFDM-Based SWIPT with Statistical Delay Constraints

For 5G wireless networks, low latency and high energy efficiency are two of the most critical key performance indicators. In this work, a framework to consider these critical requirements simultaneously by applying the notion of effective energy efficiency, and simultaneous wireless information and power transfer (SWIPT) is proposed. At first, building on the effective capacity notion, we define the effective energy efficiency of SWIPT in multiuser orthogonal frequency division multiple access systems by considering time switching (TS) scheme. Afterwards, a resource allocation problem is formulated to maximize the effective energy efficiency, subject to three constraints: minimum harvested power, average sum transmit power, and delay quality of service. It is shown that the TS scheme affects on not only the rate, but also the communication delay. Numerical results illustrate that there is a fundamental tradeoff between delay and the performance in terms of effective energy efficiency.