Physical relationships

There is continuing effort to increase the data transmission rate in evolving wireless systems. These evolving wireless systems include cellular mobile systems and wireless local area networks (WLANs). However, because of the complexity of these systems, it appears that fundamental physical relationships between transmission rate and the range over which transmission is possible are frequently overlooked. This can result in overly optimistic expectations for new wireless data systems or comparisons between systems that are not on an equal basis. This article reviews fundamental relationships between wireless system transmission rate (bit rate) and transmission range and includes the effects of some other system parameters on these relationships.