Network Management of Multicluster RT-WiFi Networks

Abstract

Applying wireless technologies in cyber-physical systems (CPSs) has received significant attention in recent years. In our previous work, a high-speed and flexible real-time wireless communication protocol called RT-WiFi was designed to support a wide range of CPSs, and we presented an implementation with a single access point (AP). To serve the CPS applications with communication nodes geographically distributed over a large area, multicluster RT-WiFi networks with multiple APs need to be deployed. Although effective scheduling algorithms have been designed to schedule tasks in RT-WiFi networks with a single AP, uncoordinated packet transmissions from multicluster RT-WiFi networks may suffer from cochannel interferences that cause performance degradation. The multicluster RT-WiFi network management problem is to resolve the cochannel interference through channel assignment for clusters and through phasing assignment for communication tasks. In this article, we first derive a conjunctive normal form encoding of the problem and design a TScheduler that searches feasible solutions through the SAT solver. A novel LRTree Scheduler is further designed to solve the problem in chain graphs while keeping the number of used channels small and the network management overhead low. A testbed of the multicluster RT-WiFi network is deployed to validate the design of the multicluster RT-WiFi network and evaluate the performance of the proposed scheduling algorithms compared to the contention-based methods in regular WiFi networks. Performance of these scheduling algorithms in large-scale networks is further evaluated through extensive simulations on both static and dynamic multicluster RT-WiFi networks.