Explicit and Implicit Temperature Constraints in Energy Harvesting Communications.

We consider an energy harvesting communication system where the temperature dynamics is governed by the transmission power policy. Different from the previous work, we consider a discrete time system where transmission power is kept constant in each slot. We consider two models that capture different effects of temperature. In the first model, the temperature is constrained to be below a critical temperature at all time instants; we coin this model as explicit temperature constraint model. We investigate throughput optimal power allocation for multiple energy arrivals under general, as well as temperature and energy limited regimes. In the second model, we consider the effect of the temperature on the channel quality; we coin this model as implicit temperature constraint model. As the dynamic range of the temperature changes significantly, the change in the thermal noise becomes non-negligible, affecting the signal to interference plus noise ratio (SINR). In effect, transmitted signals contribute as interference for all subsequent slots. In this case, we investigate throughput optimal power allocation under general, as well as low and high SINR regimes.