一种无线多媒体传感器网络分区链路调度算法

Partitioned link scheduling for wireless multimedia sensor networks

链路干扰是无线多媒体传感器网络实现大容量、实时、可靠传输的主要困难。为提高多跳传输模式下无线网络性能,基于MAC层的调度算法得到了广泛关注。调度算法为每条链路分配合理的传输时槽,降低了冲突和重传次数,能显著提高网络传输性能。但随着网络规模的增大,无论是集中式还是分布式调度算法,都存在调度开销增大和性能降低的问题。针对这一问题,根据节点分布密度和承载网络流量大小,将网络划分为密集区域和稀疏区域。稀疏区域的节点传输冲突较小,直接采用CSMA的协议。密集区域的节点传输冲突大,采用基于队列长度的分布式调度。分区调度能够有效降低网络规模扩大导致的调度算法复杂性增大的问题。仿真实验表明,分区调度算法无论是在队列长度,还是在延时性能上,较传统算法有明显改善。

Link scheduling is one of the main difficulties for large data, real-time and reliable transmission in wire- less multimedia sensor networks. To improve multi-hop transmission performance, MAC layer link scheduling algo- rithms have received extensive attention. These algorithms allocate slots for every data link. They can reduce the number of conflicts and retransmissions. However, as the network size increases, both centralized or distributed scheduling algorithms will encounter performance degradation problem. To overcome this problem, a novel schedul- ing algorithm based on network partition is proposed, which is suit for following 2 situations, in sparse region, the MAC layer switches to a simple 802.11 mode, in intensive region, the MAC layer switches to queue length based scheduling mode. Emulation results show that the proposed algorithm has a better performance in both terms of total queue length and average delay.