An Iterative ET Authorization Algorithm Clause Samples

An Iterative ET Authorization Algorithm. ‌ Motivated by the fact that energy is highly attenuated during long-distance propa- gation and in order to improve the energy efficiency, an ET authorization algorithm that can be implemented in the CP to authorize the RRHs to transmit energy directly towards the ETs located within their hexagonal energy serving area and set as ac- tive ETs is considered, whilst other ETs will be set as idle ETs. Note that only the active ETs will be assigned with dedicated beamformers for power transmission. Consequently, the active ETs can harvest energy not only from the RRHs, but also from the ambient RF signals whilst the idle ETs merely harvest energy from the surroundings. The steps of authorization are summarized in Algorithm 2. By adjusting the value of ℘nm, the size of the hexagonal energy serving area can be controlled by the CP as per practical situations, e.g., capacity restrictions and power budgets. Then, the total energy harvested by the e-th active ET, e ∈ Le, can be expressed as G [ET] = η |gHve|2 + ∑ |gHv j|2 + ∑ |gHwi|2! , (4.5) j∈Le, ▇ ▇ i∈ Li 1e where 0 ≤ η ≤ 1 indicates the conversion efficiency from the harvested RF energy to the electrical energy and is assumed to be constant and identical for all ETs; ge = [gH , · · · , gH ]H ∈ CMN×1 represents the aggregate channel vector from all the Algorithm 2 An iterative ET authorization algorithm