Choose the system benefit that's best for you

PCMA Satellite Bandwidth Optimization

Frequency Re-Use for Two-Way Satellite Communications

PCMA pairs forward and return channels in ths same bandwidth.PCMA (Paired Carrier Multiple Access) - a patented Viasat technology - is a frequency re-use technique for two-way satellite communications. It enables two different earth stations to use the same frequency, time slots, and/or CDMA code at the same time.

Using PCMA, you can choose the system benefit that's best for you:

  • More capacity to serve more customers in the same bandwidth
  • Reduce bandwidth requirements/costs to save money
  • Allocate more bandwidth per customer to improve service levels with no increase in costs

This technique can be applied with any of the commonly-used multiple access techniques such as FDMA, TDMA, or CDMA. PCMA may also be applied independently of the modulation and coding technique for the link. PCMA is used in addition to -- not instead of -- other bandwidth and power efficient modulation, coding and multiple access techniques.The benefit of PCMA is that it may effectively double the throughput of satellite systems in terms of bits/sec/Hz, with a minimal impact on the Eb/No required to achieve a desired Bit Error Rate.

As part of the development process, Viasat has performed extensive performance testing both at IF, RF, and over-the-air. The chart below shows typical bandwidth throughput you can get, with corresponding required power, when using PCMA at any given data rate.

Bandwidth and power requirements with standard channels vs PCMA enhanced.