Millimeter Wave Subscriber Loops

Advantages and drawbacks of using millimeter waves in the telephone and data subscriber distribution network are listed. Fields in which it seems attractive to use millimeter wave loops are examined. For such applications, cost and reliability constraints led to the design of very simple systems. Two systems will soon be introduced into the French subscriber plant. The first one will be commissioned in 1983 to connect groups of remote subscribers, working at 31 GHz, using a homodyne millimetric front end. The second one, still under experiment, is designed for the connection of subscribers of the integrated service communication network; working at 23 GHz, it uses time-division multiplexing to assume duplex operation. The most drastic constraint when setting up such systems is the line-of-sight requirement. Investigations of that problem, using computer-aided coverage map plotting are discussed.