Wireless LAN on 2-D Communication Tiles Using Ultra-Wideband as an Alternative Spectrum Resource

Abstract

To meet the ever increasing demand for wireless local area network (WLAN) connectivity, we propose to use the frequency range allocated for ultra-wideband (UWB) radios as an alternative spectral resource for conventional WLAN systems. Since the maximum permitted emission of UWB radios is 50-dB smaller than that of conventional WLAN devices, aerial communication range will be shortened to less than 1 m. To enhance the communication range while reducing the emission, two- dimensional communication (2DC) technology can be used. The low power UWB signals can be transferred along a 2DC-tiled floor with acceptably low loss, and can be received at arbitrary points on the floor of a room. This paper presents a scheme to use the UWB 2DC system for WLAN signal transmission. An adopter device is attached to each of WLAN access point and client station. The adopter upconverts WLAN's 2.4-GHz signal to 8- GHz (in UWB's frequency range), and downconverts the received 8-GHz signal to 2.4-GHz. The adopter is connected to the antenna port of the WLAN device, and no other modifications to the circuit, firmware, and software of the WLAN device are needed. The upconverted UWB signal is attenuated to the UWB's permitted emission level before sending. Experimental results demonstrate that the WLAN connection through prototype converters and a 2DC sheet can achieve the same order of throughput as the original 2.4-GHz aerial WLAN connection. Since each converter can choose individual upconversion frequency from the UWB's frequency range, the WLAN devices in the system virtually share the UWB's bandwidth up to 7 GHz, much wider than the 80- MHz bandwidth originally allocated for 2.4-GHz WLAN devices.