|FEBA: A Bandwidth Allocation Algorithm for Service Differentiation in IEEE 802.16 Mesh Networks
In wireless mesh networks, the end-to-end throughput of traffic flows depends on the path length, i.e., the higher the number of hops, the lower becomes the throughput. In this paper, a fair end-to-end bandwidth allocation (FEBA) algorithm is introduced to solve this problem. FEBA is implemented at the medium access control (MAC) layer of single-radio, multiple channels IEEE 802.16 mesh nodes, operated in a distributed coordinated scheduling mode. FEBA negotiates and width among neighbors to assign a fair share proportional to a specified weight to each end-to-end traffic flow.
This way traffic flows are served in a differentiated manner, with higher priority traffic flows being allocated more bandwidth on the average than the lower priority traffic flows. In fact, a node requests/grants bandwidth from/to its neighbors in a round-robin fashion where the amount of service depends on both the load on its different links and the priority of currently active traffic flows. If multiple channels are available, they are all shared evenly in order to increase the network capacity due to frequency reuse.
The performance of FEBA is evaluated by extensive simulations. It is shown that wireless resources are shared fairly among best-effort traffic flows, while multimedia streams are provided with a differentiated service that enables quality of service.
ALGORITHM / TECHNIQUE USED:
We propose a fair end-to-end bandwidth allocation (FEBA) algorithm for IEEE 802.16 nodes to negotiate bandwidth in a multi-channel environment.1 our contributions can be summarized as follows.
1) FEBA tackles the “spatial bias” problem by keeping separate queues at each node for each traversing traffic flow. Furthermore, differentiated service is provided by serving traffic flows proportionally to their priority, specified in the standard IEEE 802.16 MAC header.
2) The “hidden node” problem, which can lead to information asymmetry between flows that are one hop away from each other, can be substantially mitigated by FEBA through the so-called regranting procedure.
3) Unlike most solutions for TDMA MAC protocols, FEBA is able to react promptly to short-term variations of the traffic load in the network. FEBA is implemented in a fully distributed manner, thus, it does not incur the overhead
of signaling towards/from a centralized node, which often makes existing solutions impractical.
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