A wireless sensor network (WSNET) can support various types of queries. The energy resource of sensors constrains the total number of query responses, called query capacity, received by the sink. There are four problems in the existing approaches for energy-efficient query processing in WSNETs:
1. | the fact that sensors near the sink drain their energy much faster than distant sensors has been overlooked, | ||||
2. | routing trees (RT) are rooted at the sink, and therefore, aggregative queries are less energy-efficient, | ||||
3. | data reception cost has been ignored, and | ||||
4. | flooding is used in query distribution or RT construction. |
Notes
1Sensors are randomly deployed in a rectangular area. The dark points denote sensors with odd number of shortest hops to the sink and the gray points denote sensors with even numbers of hops to the sink. The odd and even hop sensors are interleaved with each other.