Wireless Mesh Network-based Query Optimization Technology

As the extension of wireless ad hoc network, the wireless Mesh network (WMN) addresses a great attention for its easy organize, extensible, wireless multi-hop, scalable, high bandwidth and light interfere since 2002. As yet a mass of routing protocols, MAC protocols and various transmission protocols have been put forward, specially focus on WMN's characteristics. Contrarily, the application oriented technologies such as query processing and optimization based on the WMN have rarely been studied. Query optimization is playing a very important role in database technologies such that in each step of the database development, it always gains researchers'most attention. As distribute wireless database is one of the potential applications in wireless Mesh networks, how to combine the characteristics of WMN to process query optimization is becoming the new hotspot in WMN s and database technologies.This paper is study on the query optimization technologies based on WMN. And proposed three algorithms named two phase plan generation (TPPG) algorithm, query migration algorithm (QM) and multi-query optimization (MQO) algorithm. The first phase of TPPG generates a logically optimized centralized plan, and the second phase generates distributed plans with the multiple cost evaluation models. With consideration of the load and bandwidth of the execution nodes, the algorithm mainly solves the nodes overload and disconnected problem. For the query performance degrade problem caused by some important nodes overloaded, the QM improve the possibility of decreasing transmission cost of the whole network when balancing the loads. For the case that there are many overlaps among queries, this paper takes the data sources angle, setups multi-level data sources for those queries and processes optimizing bottom up. Although takes some communication and maintaining cost, it may reduce the global transmission cost greatly, and extend the lifetime of the networks. At last, designed a proto system and evaluated these algorithms through experimental analyze.