Coexistence study on ultra-wideband and mobile cellular systems

This paper presents the results of a series of laboratory and field measurements conducted for the co-existence study on ultra-wideband (UWB) and mobile cellular systems. In these studies, we introduced UWB interference to the GSM/GPRS and IMT-DS handsets in two circumstances, firstly in the lab under controlled conditions, and subsequently in the field using commercial GSM and pre-commercial IMT-DS networks. In the laboratory, we determined how the BER (for GSM) or BLER (for GPRS) of the radio downlink varies with the C/I/sub UWB/ ratio for 30 different impulse-based UWB signal types. Measurement results obtained in the laboratory showed that a C/I/sub UWB/ ratio of 11 dB and 10 dB should be used as the condition of coexistence between a UWB device and a GSM (1800 MHz) handset, and between a UWB device and a GPRS (1800 MHz) handset respectively. For IMT-DS, results obtained using voice and data services showed that all the threshold EIRP values (for different UWB signal types used) are higher than the level currently permitted by the FCC's emission mask for handheld UWB systems i.e. -63.3 dBm/MHz for 1610-1900 MHz band and -61.3 dBm/MHz for 1 990-3 100 MHz band. This study also validates the assumption that UWB power adds up in a simple linear manner.