On-Time Communications Over Fading Channels

TL;DR

This paper studies how to maximize the on-time reception rate of packets over fading channels by modeling scheduling as a Markov decision process and proposing optimal control strategies, improving reliability in time-sensitive communications.

Contribution

It introduces a novel framework for on-time packet reception over fading channels and develops an optimal scheduling policy using MDPs to enhance on-time reception rates.

Findings

Optimal scheduling significantly improves on-time reception rate.

On-time reception rate decreases with sequence length without control.

Increasing target interval or reducing channel randomness improves on-time reception.

Abstract

We consider the on-time transmissions of a sequence of packets over a fading channel.Different from traditional in-time communications, we investigate how many packets can be received $\delta$-on-time, meaning that the packet is received with a deviation no larger than $\delta$ slots. In this framework, we first derive the on-time reception rate of the random transmissions over the fading channel when no controlling is used. To improve the on-time reception rate, we further propose to schedule the transmissions by delaying, dropping, or repeating the packets. Specifically, we model the scheduling over the fading channel as a Markov decision process (MDP) and then obtain the optimal scheduling policy using an efficient iterative algorithm. For a given sequence of packet transmissions, we analyze the on-time reception rate for the random transmissions and the optimal scheduling. Our analytical and simulation results show that the on-time reception rate of random transmissions decreases (to zero) with the sequence length.By using the optimal packet scheduling, the on-time reception rate converges to a much larger constant. Moreover, we show that the on-time reception rate increases if the target reception interval and/or the deviation tolerance $\delta$ is increased, or the randomness of the fading channel is reduced.