Efficient multimedia packet forwarding for multihomed users in wireless LANs

摘要

In many cases, a mobile user has the option of connecting to one of several 802.11 access points (APs), each using an independent channel. We consider the case when users multihome, i.e., split their traffic among all available APs, based on the channel burstiness, transmission rates and required application resilience. We consider two solution approaches for this problem: static and dynamic traffic splitting algorithms. Static algorithms solve a nonlinear program, which maximizes the average effective transmission rate satisfying the required resiliency against channel losses, and determines the number of packets transmitted over each channel a priori to the first packet transmission. In contrast, dynamic algorithms progressively select for each packet the channel that is most likely to be successful based on the most recent channel outcomes. The resiliency against channel losses is explicitly calculated, and accurate approximations suitable for the solution of the nonlinear program are given. We provide detailed characterization of static and dynamic policies with respect to varying channel conditions, resiliency, transmission rates, and number of available channels. We show that using a simple algorithm which keeps track of the most recent channel outcomes, it is possible to significantly improve the system performance over algorithms that only consider long-term channel statistics.