Polarisation division multiple access
Encyclopedia
Polarization division multiple access (PDMA) is a channel access method
used in some cellular network
s. Separate antennas
are used in this type, each with different polarization and followed by separate receivers, allowing simultaneous regional access of satellite
s.
Each corresponding earth station antenna needs to be polarized in the same way as its counterpart in the satellite. This is generally accomplished by providing each participating earth station with an antenna that has dual polarization. The frequency band allocated to each antenna beam can be identical because the uplink signals are orthogonal in polarization. This technique allows frequency reuse.
Channel access method
In telecommunications and computer networks, a channel access method or multiple access method allows several terminals connected to the same multi-point transmission medium to transmit over it and to share its capacity...
used in some cellular network
Cellular network
A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver known as a cell site or base station. When joined together these cells provide radio coverage over a wide geographic area...
s. Separate antennas
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
are used in this type, each with different polarization and followed by separate receivers, allowing simultaneous regional access of satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s.
Each corresponding earth station antenna needs to be polarized in the same way as its counterpart in the satellite. This is generally accomplished by providing each participating earth station with an antenna that has dual polarization. The frequency band allocated to each antenna beam can be identical because the uplink signals are orthogonal in polarization. This technique allows frequency reuse.
See also
- frequency division multiple access
- code division multiple accessCode division multiple accessCode division multiple access is a channel access method used by various radio communication technologies. It should not be confused with the mobile phone standards called cdmaOne, CDMA2000 and WCDMA , which are often referred to as simply CDMA, and use CDMA as an underlying channel access...
- time division multiple accessTime division multiple accessTime division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...