Ergodic Capacity of NOMA-Based Uplink Satellite Networks With Randomly Deployed Users

Allowing multiple users access simultaneously, a power-domain nonorthogonal multiple access (NOMA) scheme can provide enhanced resource utilization efficiency and has been viewed as a promising strategy in the satellite networks, to provide high quality-of-service for large number of users within limited spectrum and time resources. Taking into account the random location information of served users, imperfect channel state information (CSI), and antenna-pointing error, we study the ergodic capacity of a NOMA-based uplink satellite network in this article. Specially, we first develop a general framework for the NOMA-based system by applying standard recommendations, configurations, and channel characteristics. Then, the analytical expression for the achievable ergodic capacity of the considered network is derived. Finally, numerical simulations are provided to attest the validity of theoretical results and show the impact of various key parameters, such as location information, link quality, transmission power, imperfect CSI, and antenna-pointing error, on the considered network.