Performance Evaluation of Novel DSA Scheme that Combines Polling Method with Random Access Method

Ubiquitous wireless networks and wireless sensor networks, which consist of access points and a number of wireless terminals with simple functions, provide users with a wide range of applications such as environment monitoring and traffic surveillance. In these networks, even though each terminal sends only small data amounts at comparatively long transmission intervals, traffic loads are significant due to the very large number of terminals. The access point must be capable of accommodating the great many wireless terminals, while providing high throughput performance. This can be achieved by employing DSA, a typical centralized media access control scheme, since it has high resource utilization efficiency. In this paper, we propose a novel DSA scheme that employs both a polling-based method and a random access method; it improves throughput by using the feature that most terminals tend to send data periodically. In this scheme, the access point polls the terminals to decrease the random accesses made by the terminals as much as possible. Simulations verify that the proposed scheme offers better throughput performance than the conventional scheme