Compatibility Research On OFDM Based Ultra-Wideband Technology

UWB technology has various advantages including low interference to othercommunication systems, high data rates, low power consumption, resistence tomultipath and efficient ultilization of frequency spectrum. With these technicalsuperiorities, UWB technology has already become one of the most advanced wirelesscommunication technologies in short range. Supported by a great number ofenterprises，research institutes and universities, UWB is on its way to universalcommercilization in golable scope. However, because of the extremely widefrequency bandwidth of UWB technology which rangs from3.1to10.6GHz, UWBsystems may be intefered by other communication systems operating in the same orneighboring frequency band, or interfer others as well. This compatibility issue willinfluence the application and popularization of UWB technology. Meanwhile, OFDMbased UWB technology has also been widely used and adopted as internationalstandards. Therefore, a comprehensive compability research on OFDM based UWBtechnology is significantly necessary.This paper investigates the compatibility of OFDM based technology in variousaspects which include the interference issues between UWB systems and narrowbandsignals, WCDMA system,802.11b/g and UWB systems. To study the interferencecaused by narrowband signals to UWB systems, an OFDM-UWB system model isbuilt on SystemVue. Furthermore, the interference caused by other communicationsystems is modeled as the one caused by narrowband signals. After designing in-bandand out-of-band interfering scenarios, the author simulates the interference caused bysingle and multiple narrowband signals to the UWB system under these two scenarios.To study the interference from UWB signals to other communication systems, thispaper studies the influence imposed by UWB signals on a WCDMA system.Considering the future application of UWB, the author proposes two differentpractical interfering scenarios, which are extreme short distance and indoorinterference. By utilizing the UWB system and a WCDMA system built on Simulink, the interference caused by UWB signal to a WCDMA system is simulated. Based onthe simulation results, hardware tests on anti-interference performance of UWBtechnology is also performed. A compatibility test hardware platform is constructedwith the DV9110UWB development kit. A Wireless USB adaptor set and an802.11b/g wireless router are used to simulate the interference between UWB systems andthe out-of-band interference.The results of simulations and hardware tests demonstrated the followingconclusions. First, the interference caused by single in-band narrowband signal ismainly determined by the signal power. Furthermore, interference occurs only if thepower is relative high enough. Second, multiple in-band narrowband signals willsignificantly effect UWB systems. Third, even if EIPR is in accordance with the FCCregulation, UWB signals still will largely interfere with WCDMA systems. Thereforea more strict EIRP regulation should be set based on this. Fourth, the interferencebetween UWB systems is serious. Fifth, out-of-band interference has no impact on theperformance of UWB systems. The analyses and results of simulations and hardwaretests provide guidelines and reference to the researches on UWB technology.