Buferng techniques in sleep doze coordination and grid based clustering protocols as power management schemes for wireless sensor networks

In this paper, we outline an approach to improve the lifespan of a wireless sensor network by introducing a variant to standard sleep synchronization protocols. A multilayered architecture is used. To ensure even higher scalability and lower message size in any particular layer, number of layers is limited to four and each layer is broken into grids. Each grid acts a localized network where data aggregation and lifetime maximization algorithms are being run. In standard sleep protocols like GAF, each grid must have one of its nodes in active state. Our sleep protocol considers one node per grid to be in the idle listening state called the ´doze´ state for a fixed interval of time. Thus we propose a three state proactive algorithm in the form of the Sleep Doze Coordination (SDC) protocol to lower the duty cycle of the each sensor node and maximize the network lifespan with lower power consumption. Node buffers are provided to bring about higher data accuracy and lossless network operation. When node buffer gets filled to its capacity by data messages from the lower layer, it signals the ´dozing´ node to transit to the active state. Thus the node does not have to remain active throughout its ´on´ period and its overall lifespan increases for a given amount of energy. Results indicate that near-optimal performance of SDC is achieved when buffer size is large enough to hold 25 data messages. SDC increases network lifetime by approximately 20% over previous protocols like GAF and S-DMAC.