Age of Information of Multi-Source Systems with Packet Management

In this paper, we propose a new transmission scheme in the multi-source system to improve the freshness of the received packets. In our proposed scheme, each source generates its packet through an independent and identical Bernoulli process at the beginning of each time slot, and then randomly selects one channel from multiple orthogonal frequency channels to perform repeat transmission of its packet across multiple time slots. We then analyze the average age of information (AoI) to characterize the freshness of the received packets. Specifically, we derive new closed-form expressions for the average AoI achieved by the proposed transmission scheme for three packet management policies. The simulation results corroborate our analysis and demonstrate that the proposed transmission scheme can achieve a lower average AoI than the existing scheme for the three considered packet management policies. In addition, the impact of system parameters, such as the packet generation probability, the numbers of time slots and orthogonal frequency channels, and the channel error probability, on the average AoI is examined.