Specs and security
Link-16 operates between the frequencies of 960-1215 MHz. This allocates a bandwidth of 255 MHz. Link-16 has a maximum capacity of 238 kbps.[14] Minimum Shift Keying is used to modulate the signal.[15]
Link-16 shares this radio band by using Time Division Multiple Access to allocate broadcasting slots. Slots are about 7.8 milliseconds each (128 time slots/second), and a participant will have several slots, broadcasting specific information on each slot. Link-16 uses synchronous TDMA, and if a participant has no new information to broadcast, the previous message is repeated. This way, if a new participant connects, it will have immediate access to the most recent information.[16]
Frequency Hopping
Because Link-16 is used primarily in military applications, data security and reliability is essential. One method used to prevent signal jamming is frequency hopping. The frequency is changed for each time slot so that the messages are not dependent on a single frequency.[5]
Link-16 shares this radio band by using Time Division Multiple Access to allocate broadcasting slots. Slots are about 7.8 milliseconds each (128 time slots/second), and a participant will have several slots, broadcasting specific information on each slot. Link-16 uses synchronous TDMA, and if a participant has no new information to broadcast, the previous message is repeated. This way, if a new participant connects, it will have immediate access to the most recent information.[16]
Frequency Hopping
Because Link-16 is used primarily in military applications, data security and reliability is essential. One method used to prevent signal jamming is frequency hopping. The frequency is changed for each time slot so that the messages are not dependent on a single frequency.[5]
Spread Spectrum Modulation
Another way to secure data is spread spectrum modulation.
This technique is based off Shannon's equation: Capacity = Bandwidth*log2 (1 + SNR)
It becomes clear that by spreading the signal over a wider bandwidth, the same capacity can be achieved in the presence of signal noise generated by jammers.[17] Using spread spectrum modulation means that in addition to producing a jamming signal over a much larger range of frequencies, the jamming signal must also be more powerful. The downside of this approach is the use of bandwidth. Spreading the spectrum over a range of frequencies is clearly a less efficient use of bandwidth.