Leveraging Edge Caching in NOMA Systems with QoS Requirements

TL;DR

This paper explores how integrating caching with NOMA in 5G systems can reduce outage probabilities, especially when weaker users cache data for stronger users, with analytical and simulation validation.

Contribution

It introduces cache-aided NOMA with a focus on outage probability analysis and optimal power allocation strategies to enhance system reliability.

Findings

Cache-aided NOMA reduces union-outage probability.

Optimal power allocation minimizes outage in cache-aided NOMA.

Simulation confirms analytical outage probability results.

Abstract

Non-Orthogonal Multiple Access (NOMA) and caching are two proposed approaches to increase the capacity of future 5G wireless systems. Typically in NOMA systems, signals at the receiver are decoded using successive interference cancellation in order to achieve capacity in multi-user systems. The leveraging of caching in the physical layer to further improve on the benefits of NOMA is investigated, which is termed cache-aided NOMA. Specific attention is given to the caching cases where the users with weaker channel conditions possess a cache of the information requested by a user with a stronger channel condition. The probability that any of the users is in outage for any of the rates required for this NOMA system, defined as the "union-outage," is derived for the case of fixed-power allocation, and the power allocation strategy that minimizes the union-outage probability is derived. Simulation results confirm the analytical results, which demonstrate the benefits of cache-aided NOMA on reducing the union-outages probability.