Wireless access system for Wide Area Ubiquitous Network

This paper introduces a wireless access system for the wide area ubiquitous network (WAUN), which is a large cell-based public sensor network, and provides feasibility study results gained through field tests. The wireless access system uses several key technologies to accommodate widely dispersed small simple terminals. First, to realize the large cell radius of several kilometers, space and site diversity technique based on digital radio over optical fiber (DROF) is developed. Second, an intelligent multiple access control scheme, a combination of demand assignment and random access, is employed to effectively accommodate tens of thousand of wireless terminals (WTs) per cell. Finally, techniques that yield low power consumption are introduced to create the long WT lifetimes needed. The system performance realized by the above-mentioned technologies is confirmed by field tests.