Over-the-air computation is a promising technique for efficiently aggregating data in sensor networks. This method requires that signals from all nodes arrive at the sink aligned in signal magnitude, which faces the reliability issue, especially in times of channel fading. To solve this problem, in this letter, we propose an amplify-and-forward based relay, Coherent Relay with Node Scheduling (CohR-NS), where a relay node is used to help forward signals of multiple nodes. Relay transmission power (TP) increases with the number of nodes using the relay, which is a bottleneck. We investigate how relay TP changes with relay position, and under the constraint of relay TP, study (i) how to select nodes to use relay when not all nodes requiring a relay can be supported simultaneously, (ii) how to select more nodes to use relay so as to reduce node TP, when there is a surplus in relay TP. We formulate this as an ILP (integer linear programming) problem, propose an efficient heuristic method, and confirm its effectiveness by simulation evaluation.

中文翻译：

---

基于 AF 的无线计算的节点调度

空中计算是一种很有前途的技术，可以有效地聚合传感器网络中的数据。这种方法要求来自所有节点的信号到达接收端的信号幅度对齐，这面临着可靠性问题，特别是在信道衰落时。为了解决这个问题，在这封信中，我们提出了一个基于放大转发的中继，相干继电器与节点调度（CohR-NS），其中中继节点用于帮助转发多个节点的信号。中继传输功率（TP）随着使用中继的节点数量的增加而增加，这是一个瓶颈。我们研究了relay TP如何随relay位置而变化，并在relay TP的约束下，研究（i）当不能同时支持所有需要relay的节点时如何选择节点使用relay，（ii）如何选择更多的节点来使用relay。当中继 TP 有盈余时，使用中继来减少节点 TP。我们将其表述为 ILP（整数线性规划）问题，提出一种有效的启发式方法，并通过仿真评估确认其有效性。