Basics of Signal Duplexing

Signal Duplex

A duplex communication scheme is a point-to-point system composed of two or more connected devices that can communicate with one another in both directions.

Duplex systems are employed in many communications networks, either to allow for concurrent communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field.

There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX).

A full-duplex (FDX) system, allows communication in both directions, and, unlike half-duplex, allows this to happen simultaneously.

Land-line telephone networks are full-duplex since they allow both callers to speak and be heard at the same time, with the transition from four to two wires being achieved by a hybrid coil in a telephone hybrid. Modern cell phones are also full-duplex.

The Duplex Scheme Available for the Mobile Wimax are , FDD, TDD, H-FDD [Half Duplex FDD].

For the duplexing scheme FDD, TDD, H-FDD are available options in case of mobile wimax. 

• TDD: It has same frequency band for UL/DL.2. Frame is divided in to DL subframe & UL subframe in the time domain. 
• FDD: Different frequency band,2. UL/DL subframes are overlapped in the time domain. 
• H-FDD: Two different frequency bands for DLand UL .2. DL/UL subframes dont overlap in the time domain.

-DR