A detailed analysis of MMDS and LMDS

The Local Multipoint Distribution System (LMDS) and Multichannel Multipoint Distribution System (MMDS) are the regulatory acronyms given to the 28 GHz and 2.5 GHz transmission bands in many jurisdictions around the world. Each of these bands have associated technical and application parameters that will have a profound affect on the quickly converging markets. This article addresses the technical issues associated with these bands and examines the application environment for these systems. The primary technical focus of equipment vendors for both of these bands has to be the network design and the way that the networks can be constructed to provide ubiquitous service to customers. As such there are a number of technical parameters that affect the design of the system including signal propagation characteristics, carrier energy levels, modulation schemes, error detection and correction mechanisms, and interference isolation requirements. The technical issues tie directly into operating issues such as coverage area, reliability, capacity, and the general feature/benefit relationship required for any successful system.