Minimum Age of Information in Internet of Things with Opportunistic Channel Access

TL;DR

This paper proposes an optimization framework for minimizing the Age of Information in IoT systems with opportunistic channel access, using advanced mathematical techniques to find the global optimum.

Contribution

It introduces a novel optimization approach combining Dinkelbach, BCD, and monotonic optimization to minimize AoI in IoT with opportunistic access.

Findings

The proposed method effectively minimizes average AoI.

Global optimal solutions are obtained via polyblock algorithm.

Numerical results confirm the method's validity.

Abstract

This paper investigates an Internet of Things (IoT) system in which multiple devices are observing some object's physical parameters and then offloading their observations back to the BS in time with opportunistic channel access. Specifically, each device accesses the common channel through contention with a certain probability firstly and then the winner evaluates the instant channel condition and decides to accept the right of channel access or not. We analyze this system through the perspective of Age of Information (AoI), which describes the freshness of observed information. The target is to minimize average AoI by optimizing the probability of device participation in contention and the transmission rate threshold. The problem is hard to solve since the AoI expression in fractional form is complex. We first decompose the original problem into two single-variable optimization sub-problems through Dinkelbach method and Block Coordinate Descent (BCD) method. And then we transform them to Monotonic optimization problems by proving the monotonicity of the objective functions, whose global optimal solution is able to be found through Polyblock algorithm. Numerical results verify the validity of our proposed method.