UWB wireless LAN by 2D-communication tile system based on direction-dependent frequency shift

To overcome the lack of bandwidth due to increase of wireless devices, using ultra-wideband (UWB) technology is attractive. However, a problem is the signal transmission power of UWB is restricted to as small as -41.3 dBm/MHz. To enhance the communication range, two-dimensional communication (2DC) technology is effective. UWB 2DC environment can be extended to cover the entire room by laying the 2DC sheet over the floor. As 2DC tile system behaves as just a physical medium, conventional communication protocols including Wi-Fi can be used. A previous study proposed to use the frequency range allocated for UWB radios as an alternative spectrum resource for conventional wireless local area network (WLAN) system in the 2DC environment. Devices on the 2DC tile can use the system by attaching an adapter. The adapter consists of couplers and a circuit that converts 2.4-GHz WLAN signals to UWB frequency range signals. In this paper, we propose direction-dependent frequency shift (DDFS) scheme for active tile 2DC. Experimental results demonstrate that the WLAN connection through prototype system can achieve 60% of throughput compared to the original 2.4-GHz WLAN connection, where at most 40-dB signal attenuation in the 2DC sheet and the coupler is assumed.