PDMA (Polarisation Division Multiple Access) Explained

This article explains PDMA, or Polarisation Division Multiple Access, and its applications. Over time, numerous multiple access techniques have been developed to allow multiple subscribers, users, or clients to share common resources. These include FDMA, TDMA, CDMA, and OFDMA, among others.

PDMA is another multiple access technique. Its distinguishing feature is that it separates signals using different polarisation types of the antenna.

PDMA leverages vertical and horizontal polarisation, as illustrated below:

This approach allows two distinct signals to share the same frequency without causing interference, since each signal is transmitted with a different polarisation.

Applications of PDMA

Satellite communication systems commonly utilize PDMA. In fibre optic communication, DP-QPSK (Dual Polarisation Quadrature Phase Shift Keying) is used for multiplexing. This technique significantly increases data rates over a single fibre optic cable. To achieve these high speeds, the initial high-speed data stream is divided into slower streams, which are then vertically and horizontally polarised before transmission.