We propose and evaluate the performance of a Non-Orthogonal Multiple Access (NOMA) dual-hop multiple relay (MR) network from an information freshness perspective using the Age of Information (AoI) metric. More specifically, we consider an age dependent (AD) policy, named as AD-NOMA- MR, in which users only transmit, with a given probability, after they reach a certain age threshold. The packets sent by the users are potentially received by the relays, and then forwarded to a common sink in a NOMA fashion by randomly selecting one of the available power levels, and multiple packets are received if all selected levels are unique. We derive analytical expressions for the average AoI of AD-NOMA-MR. Through numerical and simulation results, we show that the proposed policy can improve the average AoI up to 76.6% when compared to a previously proposed AD Orthogonal Multiple Access MR policy.

翻译：我们提出并评估了一种用信息新鲜度指标的角度考虑的非正交多用户接入（NOMA）双跳多中继（MR）网络的性能。具体而言，我们考虑了一种年龄依赖（AD）策略，命名为AD-NOMA-MR，在该策略中，用户仅在达到一定的年龄阈值后以一定的概率进行传输。用户发出的数据包可能被中继接收，然后通过随机选择可用功率级别将其以NOMA的方式转发至一个公共汇聚点。如果选择的所有功率级别均唯一，则可以接收多个数据包。我们推导了AD-NOMA-MR的平均Age of Information（AoI）的解析表达式。通过数值和仿真结果，我们表明所提出的策略可以将平均AoI提高高达76.6％，并与先前提出的AD正交多用户接入MR策略进行了比较。