Radio Equipment and Systems (RES); Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 2: Physical Layer (PHL) (Second Edition)
This second edition European Telecommunication Standard (ETS) gives an introduction and overview of the complete Digital Enhanced Cordless Telecommunications (DECT) Common Interface (CI). This part of the DECT CI specifies the physical channel arrangements. DECT physical channels are radio communication paths between two radio end points. A radio end point is either part of the fixed infrastructure or a Portable Part (PP)@ typically a handset. The assignment of one or more particular physical channels to a call is the task of higher layers. The Physical Layer (PHL) interfaces with the Medium Access Control (MAC) layer@ and with the Lower Layer Management Entity (LLME). On the other side of the PHL is the radio transmission medium which has to be shared extensively with other DECT users and a wide variety of other radio services. The tasks of the PHL can be grouped into five categories: a) to modulate and demodulate radio carriers with a bit stream of a defined rate to create a radio frequency channel; b) to acquire and maintain bit and slot synchronization between transmitters and receivers; c) to transmit or receive a defined number of bits at a requested time and on a particular frequency; d) to add and remove the synchronization field and the Z-field used for rear end collision detection; e) to observe the radio environment to report signal strengths.