What is PDMA?
This page describes what is PDMA or Polarisation Division Multiple Access and PDMA application.
There are many multiple access techniques evolved for sharing the common resources among multiple subscribers or users or clients. These include FDMA,TDMA,CDMA,OFDMA etc. PDMA is also multiple access technique which separates the signals using different polarisation type of teh antenna. PDMA uses vertical and horizontal polarisation as shown in the figure.
This helps two different signals share the same frequency without resulting into any interference issue between them as both will be transmitting different polarised signals. Typically satellite communication systems employ this PDMA technique.
The fibre optic communication system employs DP-QPSK referred as Dual Polarisation Quadrature Phase Shift Keying for multiplexing. This technique help increase the data rates over single fibre optic cable. To achieve this high speed data first is divided into slow data streams, which later vertically and horizontally polarised before transmission.