Optimizing the use of the space segment is a key criterion for selecting a satellite modem: the space segment is a recurring leasing cost which cannot be avoided. Thus, the choice of multiple access protocol in this segment by a network of stations will depend on the duration of the project, investment materials, flexibility and facilities requested.
zThere are several communication protocols: SCPC FDMA, TDMA, TDM (DVB-S2)/TDMA, CDMA, etc. that define how VSATs access and use the space segment allocated by the owner of the satellite.
We propose the use of TDMA (Time Division Multiple Access) FM (Frequency multiplier) DAMA (Dynamic Allocation Multiple Access).
To this goal, we propose the use of SKYWAN family of satellite modems manufactured by NDSatcom, Skywan 5G
This modem is a MF-TDMA VSAT system that can use up to 16 frequencies. Each frequency has a maximum capacity of 20 Mega Symbols per second allowing a network capacity up to 320 Mbps, depending on the selected FEC (Forward Error Correction) convolution algorithm.
A single frequency, with a transmission rate of the aggregate, can transmit any type of information ranging from pure data, voice, and facsimile to the multimedia applications.
Depending on the size of the required capabilities, transmission rates on different frequencies are configurable from 200 kBaud to 12 MBaud. It is then possible through frequency-hopping to switch from a transmission rate to another.
The SKYWAN series of modems can be a so-called DAMA (Dynamic Allocation Multiple Access) that can allocate bandwidth on demand, by sharing a set of carriers between all applications. This means that at any time the satellite bandwidth is allocated according to individual demands of the stations, and released as soon as it is no longer used. When a station does not transmit, available capacity can be used by any other station in the network.
Each station is able to apply all the bandwidth from 100 to 125 ms in the configured frame structure. This allocation of capacity is effective in less than a second after the demand for bandwidth providing unmatched dynamic allocation of bandwidth in the industry.
Network topology based on a Star configuration concept may then be advanced to migrate to a hybrid or mesh topology where each station can directly communicate with any other station without passing through a hub or a station master. The system can be configured according to more flexible criteria in terms of priority, minimum bandwidth, permalinks, etc. This is done between each station being more or less important in terms of transmission capacity.
At any time, the user can become its own operator as independently as possible.