Compatibility of Ultra Wide Band (uwb) Radio with Power Line Communication Systems in Indoor Environment

INTRODUCTION The Ultra wideband (UWB) radio communication is known as a “carrier-free”, “baseband” or “impulse” technology. The basic concept is to transmit and receive an extremely short duration burst of pulses, typically having few tens of picoseconds in duration, with the resulting waveforms extremely broadband in frequency [1]. The UWB systems send a train of pulses with a very low duty cycle (on the order 1/100, 1/1000 or less) using usually the Time Hopping (TH) modulation [2]. Typical duty cycle in TH modulation is about 10-50 ns, which gives signals with repetition pulse frequencies from 20 MHz to 100 MHz. The Federal Communication Commission (FCC) requirements for UWB signal in communication devices [3] are fixed in terms of lower and higher frequency limits. The FCC regulation limits the bandwidth occupancy of a single UWB pulses in the range 3.1 GHz 10.6 GHz with different limits for indoor and outdoor environments. Current regulations have not a coordinated frequency allocation across European Union; the ETSI requirements for UWB do not exist, but two working groups are active: the CEPT SE24 and the ETSI TG31a. Due to the increasing interest of UWB technology for possible application as wireless personal area network (WPAN), it is important to evaluate the coexistence between UWB radio communication systems and other communication systems operating in indoor environment as power line communication (PLC) systems [1]-[6]. The PLC technology is used to transfer data on power lines. New generation of PLC have been developed in the last few years allowing data transmission rates of a few Mbit/s with frequencies up to 30 MHz [4]-[5]. Since the frequency occupancy of a single UWB pulse and PLC are very different, it seems difficult that UWB and PLC systems can interfere. Nevertheless, train of UWB pulses can have frequency peaks at few megahertzs and therefore interferences can occur. To this aim in this work the interferences produced by UWB systems on PLC systems are analysed experimentally in order to evaluate the compatibility between UWB and PLC systems.