Ultra-wideband Wireless
Avoiding interference from other devices

The most challenging technical problem associated with using UWB, is finding ways to prevent other emitters from interfering with UWB devices. Other radio systems have a strong advantage in this area. All other systems are fitted with a front-end filter, which prevents interference from transmitters operating outside of their reception bands. Unfortunately, a UWB receiver needs to have an open front-end filter, to allow for a broad spectrum of frequencies, including signals from potential sources of interference. The ability to overcome this impediment, which is sometimes referred to as jamming resistance, is a key attribute of a well-designed UWB receiver. One approach to improving jamming resistance is to install notch filters, which attenuate the narrow parts of the spectrum, where interference is likely to occur. Another solution is to use automatic notch filters, which seek out and diminish the signals of particularly strong sources of narrowband interference.

Multipath Interference
Multipath interference, as discussed in Module 4, is also an issue. However, clever design can permit UWB systems to take advantage of this phenomenon. The narrow pulses of UWB make it possible for some receivers to resolve the separate multipath streams and simultaneously lock onto the various reflected signals. Then a comparison in near real-time determines if a received bit is a one or a zero. This bit-checking function actually improves the performance of the receiver.