We investigate the age-of-information (AoI) in the context of random access networks, in which transmitters need to send a sequence of information packets to the intended receivers over a shared spectrum. Due to interference, the dynamics at the link pairs will interact with each other over both space and time, and the effects of these spatiotemporal interactions on the AoI are not well understood. In this paper, we straddle queueing theory and stochastic geometry to establish an analytical framework, that accounts for the interplay between the temporal traffic attributes and spatial network topology, for such a study. Specifically, we derive accurate and tractable expressions to quantify the network average AoI as well as the outage probability of peak AoI. Besides, we develop a decentralized channel access policy that exploits the local observation at each node to make transmission decisions that minimize the AoI. Our analysis reveals that when the packet transmissions are scheduled in a last-come first-serve (LCFS) order, whereas the newly incoming packets can replace the undelivered ones, depending on the deployment density, there may or may not exist a tradeoff on the packet arrival rate that minimizes the network average AoI. Moreover, the slotted ALOHA protocol is shown to be instrumental in reducing the AoI when the packet arrival rates are high, yet it cannot contribute to decreasing the AoI in the regime of infrequent packet arrivals. The numerical results also confirm the efficacy of the proposed scheme, where the gain is particularly pronounced when the network grows in size because our method is able to adapt the channel access probabilities with the change of ambient environment.
翻译:我们从随机访问网络的角度调查信息年龄( AoI) 。 在随机访问网络中, 发送器需要通过共享频谱向预定接收器发送一系列信息包。 由于干扰, 链接对配的动态将在空间和时间上相互影响, 以及AoI上这些局部时际互动的影响, 我们无法很好地理解。 在本文中, 我们通过排列队列理论和随机几何来建立一个分析框架, 用于计算时间流量属性和空间网络表层之间的相互作用。 具体地说, 我们得出准确和可移动的表达方式, 以量化网络平均访问量以及最大访问量的概率。 此外, 我们开发了一个分散的频道访问政策, 利用每个节点的本地观测做出传输决定, 最大限度地减少 AoI 。 我们的分析显示, 当包传输安排在最后到的首存( LCFS) 顺序中, 因为新收到的数据包可以替换未交付的版本, 具体取决于部署密度, 我们获得的数据量的准确性和可移动的表达方式, 特别是AOFI 递增的版本的速度, 当A 递增到A 时, 当OFI 时, 递增到的版本的速度是不断递增到 时, 当OFI 时, 当OFI 时, 递增 递增到 时, 时, 递增 递增到 时, 当OFI 时, 时, 机率 递增 递增 时, 递增到 。