Joint Optimization of Power Allocation and Channel Ratio for Offloading in NOMA-HetNets

Surge in number of cellular users and data-intensive applications require the traditional cellular networks to evolve towards a more promising heterogeneous cellular networks (HetNets). Offloading in HetNets alleviates congestion on the overloaded cellular network where the femto base stations (FBS) acts as offloading spots. The offloaded user (OU) is paired with the user available at the FBS (called as pairing user (PU)) and served using non-orthogonal multiple access. Two parameters namely, power allocation factor (PAF), i.e., the power to be allocated to the OU, and channel ratio (CHR), i.e., the ratio of channel gain between the OU and the PU play a crucial role in determining the ergodic rate achieved by the OU. If the PAF and the CHR are not optimally selected, it results in degradation in overall rate performance. This work jointly optimizes the PAF and the CHR to maximize the ergodic rate performance of the OU. The impact of optimized and non-optimized parameters on the performance of OU is studied to prove the advantage of using optimized scenario for the OU. An increase of upto 3 times is observed in the ergodic rate and sum ergodic rate by using the optimized parameters.