Benefits of ISI in the Indoor Environment

In this section, the problems caused by a multipath channel are discussed in more detail. First, a short descriptive overview will be given on the specific categories under which a multipath environment can be classified. Along with this, it is indicated how this is anticipated for in some of the wireless systems (e.g. 802.11a/b/g) that have been discussed earlier in this book. Towards the end of this section, it should become clear to the reader under which particular circumstances the extra costs of using a special architecture such as the multifinger rake receiver or a multi-antenna setup can be justified as a way to increase diversity and as such also the reliability of a wireless link. First, in the next few sections, some important concepts such as the delay spread of the radio channel will be introduced. After this, the impact of the properties of the wireless channel on the reliability of the link are discussed. It will be pointed out that, in contrast to common belief, intersymbol interference is actually a necessary precondition to improve the reliability of a wireless system that is operated in a multipath indoor environment.