In the last 10-15 years traffic on Satcom Networks has ex-grown exponentially. Data services (Internet) are the major user of bandwidth followed by voice. Bandwidth is a scarce resource as it is limited by the Satellite capacity. The sharing of bandwidth is a primary focus area by network and communication provider.
DAMA (Demand Assigned Multiple Access) provides this need for sharing a limited resource as and when required. This technology is defined as using a channel only when required by clients.A user terminal requests the use of a communication channel via a satcom modem. The request is logged to a network control system (NCS). After the user has completed the task the channel reverts back to the NCS and is assigned to the next user.
How DAMA Works?
This system is a useful addition in areas where network bandwidth is used by many clients and PAMA (Permanently Assigned Multiple Access) is not possible. Communication channels are dual carrier frequencies used for transmission and receiving signals. The system ensures that once a channel is allotted a particular time slot it is not available for others until their session has ended. The sequential use of a single channel by many users and at different times allows for maximum use of the channel. For example a six channel system using DAMA modems can allow six conversations at the same time with multiple nodes whereas a six channel PAMA employed system on a similar network can also have six conversations but no other nodes can use the channel when it is not being used.
This technology is used mainly for satellite communications particularly in VSATs (Very Small Aperture Terminal). VSATs primary function is on-the-move communications. Maritime use by onboard VSATs allows for internet and voice access via satellites that are in geosynchronous orbits allowing for very fast and reliable ship-to-shore communication or ship-to-ship through satcom modems.
DAMA was designed in 1968 by the United States government primarily for the military. As communication needs expanded private telecommunication players adopted this standard and brought it to mainstream communication.
DAMA technology ensures reliable communication connectivity when satellite bandwidth is limited and cost is an important consideration. Its use in DAMA modems has become an industry standard used by Raditek and other leading telecommunication technology hardware manufacturers.