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_UWB ratio for 30 different impulse-based UWB signal types. Measurement results obtained in the laboratory showed that a C/I_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.