Link 22
Comparison with Link 11
Link 11 has been in existence since the mid-1950s. It was conceived to support small numbers of units performing mainly an Anti-Air Warfare (AAW) role on a single network.

Link 22

Section Title: Comparison with Link 11
Table Section Text: Link 11 has been in existence since the mid-1950s. It was conceived to support small numbers of units performing mainly an Anti-Air Warfare (AAW) role on a single network.

Link 11	Link 22

Roll Call Transmission allocation. Increased net cycle times due to increasing numbers of Participating Units (PUs) and tracks.	Uses TDMA which provides deterministic access to the network. Prioritization of messages ensures most important are transmitted before less important

No way to transmit urgent information	The use of Priority Injection timeslots in the TDMA structure can be used to minimize the delay in the transmission of urgent information

Limited number of participants (62)	More units (125)

A restrictive "playing area" based on the ranges of individual platforms, and more importantly, on its method of reporting its position, and that of its tracks, based on its distance from a Data Link Reference Point (DLRP).	Uses the Worldwide Geodetic System (WGS-84), same as Link 16, so no limitation. Each NILE unit can operate simultaneously on up to four networks; a Super Network can be composed of up to 8 networks.

All units have to be in RF connectivity with the Net Control Station, again limits the area of operation	The use of routing & relay protocols greatly increases the playing area, even when using line-of-sight UHF.

Relatively easy to spoof because of weaknesses in the security of the system	More difficult to spoof, and any attempts to spoof are easier to detect, due to features such as time based encryption

Relatively easy to jam a single HF or UHF fixed frequency network	A single HF or UHF fixed frequency network can still be jammed, however with multiple networks it is more difficult to jam all at the same time.

The encryption level is not sufficient for the processing power of modern computers	Uses same crypto chip as Link 16. Crypto technology is being updated to meet future requirements

The loss of the Net Control Station will cause the network to collapse	Does not use a Net Control Station. Designed with no single point of failure

The accuracy of Link 11's M-Series messages is inadequate for modern targeting	Data items are designed with improved ranges and granularity using same data dictionary as Link 16

Available waveforms limit communications under bad RF conditions (as occur in polar regions)	A variety of more robust waveforms. In bad conditions strong coding can be used to maintain communication at the expense of throughput

M-Series messages difficult to translate making data forwarding between links complex	Link 22 is part of the J-Series family of messages, uses the same data dictionary as Link 16 and so makes translation and forwarding relatively easy compared to Link 11

Limited Bandwidth (1,800 bit/s for fast and 1,090 bit/s for slow)	Range of bandwidths available depending on coding and media for example fixed frequency: HF 1,493 – 4,053 bit/s UHF 12,666 bit/s

Sentence(s)

For Link 22, the UHF fixed frequency data transfer rate is 12,666 bit/s.

final_sentence: For Link 22, the UHF fixed frequency data transfer rate is 12,666 bit/s.