论文标题
具有嘈杂渠道的超密集物联网（IoT）系统中信息时代的性能分析
Performance Analysis of Age of Information in Ultra-Dense Internet of Things (IoT) Systems with Noisy Channels
论文作者
论文摘要
在本文中，研究了一个密集的物联网（IoT）监视系统，其中使用载体Sense多重访问（CSMA）方案，大量设备竞争将及时的状态数据包传输到其相应的接收器的及时接收器。当每个设备完成一个变速箱时，由于可能的传输故障，必须考虑两个带有和没有传输反馈的情况。特别是，对于没有反馈的情况，该设备使用策略（i）：它将转到空闲状态并释放通道，而无论传输的结果如何。对于具有完美反馈的情况，如果传输成功，则该设备将转到空闲状态，否则，它使用策略（W），即，它将转到等待状态并重新登陆频道访问；或者它使用策略，即，它将保持在服务状态，并占据此渠道尝试其他传输。对于这三个政策，每个设备的平均信息年龄（AOI）的封闭形式表达式是在有或没有预先服务的方案下进行的。结果表明，对于每种政策，与没有先发制人的计划相比，在服务中先发制人的计划总是达到平均较小的AOI。然后，开发了具有保证准确性的平均场近似方法，以分析具有无限数量设备数量的考虑系统的渐近性能，并且系统参数对平均AOI的影响。仿真结果表明，即使对于少数设备，提出的平均场近似值也是准确的。结果还表明，与策略（i）和（w）相比，策略（S）达到了最小的平均AOI，并且平均AOI并不总是随着所有三个策略的到达率而降低。
In this paper, a dense Internet of Things (IoT) monitoring system is studied in which a large number of devices contend for transmitting timely status packets to their corresponding receivers over wireless noisy channels, using a carrier sense multiple access (CSMA) scheme. When each device completes one transmission, due to possible transmission failure, two cases with and without transmission feedback to each device must be considered. Particularly, for the case with no feedback, the device uses policy (I): It will go to an idle state and release the channel regardless of the outcome of the transmission. For the case with perfect feedback, if the transmission succeeds, the device will go to an idle state, otherwise, it uses either policy (W), i.e., it will go to a waiting state and re-contend for channel access; or it uses policy (S), i.e., it will stay at a service state and occupy this channel to attempt another transmission. For those three policies, the closed-form expressions of the average age of information (AoI) of each device are characterized under schemes with and without preemption in service. It is shown that, for each policy, the scheme with preemption in service always achieves a smaller average AoI, compared with the scheme without preemption. Then, a mean-field approximation approach with guaranteed accuracy is developed to analyze the asymptotic performance for the considered system with an infinite number of devices and the effects of the system parameters on the average AoI are characterized. Simulation results show that the proposed mean-field approximation is accurate even for a small number of devices. The results also show that policy (S) achieves the smallest average AoI compared with policies (I) and (W), and the average AoI does not always decrease with the arrival rate for all three policies.
