A Two-Stage Link Scheduling Scheme for Variable-Bit-Rate Traffic Flows in Wireless Mesh Networks

Providing end-to-end quality of service (QoS) for delay-sensitive flows with variable-bit-rate (VBR) traffic in wireless mesh networks is a major challenge. There are several reasons for this phenomenon, including time-varied bandwidth requirements, competition for transmission opportunities from flows on the same link, and interference from other wireless links. In this paper, we propose a flexible bandwidth allocation and uncoordinated scheduling scheme, called two-stage link scheduling (2SLS), to support flow delay control in TDMA-based wireless mesh networks. The scheme is implemented in two stages: slot allocation and on-the-go scheduling. The slot allocation mechanism allocates contiguous time slots to each link in each frame based on predefined maximum and minimum bandwidth requirements. Then, each link´s on-the-go scheduling mechanism dynamically schedules the transmissions within the allocated time slots. The objective is to maximally satisfy the demand of all flows on the link according to the bandwidth requirements and channel condition. Compared with traditional slot allocation approaches, 2SLS achieves higher channel utilization and provides better end-to-end QoS for delay-sensitive flows with VBR traffic.