Abstract
Wide area ubiquitous wireless networks, which consist of access points (APs) connected to the fixed network and a great many wireless terminals (WTs), can offer a wide range of applications everywhere. In order to enhance network performance, we need to collect different kinds of data from as many WTs as possible; each AP must be capable of accommodating more than 103 WTs. This requirement 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 three new techniques to enhance throughput performance; (1) considering that most terminals tend to send data periodically, it employs both polling-based schemes, i.e. request-polling and data-polling, and a random access scheme. (2) In order to enhance bandwidth utilization effectiveness by polling, the polling timing is decided according to the data generation timing. (3) The AP decides the polled data size according to the latest distribution of data size and polls the WT for the data directly. If the data-polling size can not be determined with confidence, the AP uses request-polling instead of data-polling. Simulations verify that the proposed scheme offers better transmission performance than the existing schemes.
