DB - Digital Battlespace

Bandwidth challenges existing data link order

6th June 2019 - 16:45 GMT | by Thomas Withington in Toulouse


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For almost four decades NATO’s Link 16 tactical data link has proved its worth as a vital communications conduit for air operations, but thoughts are now turning to its successor.

The Link 16 tactical data link (TDL) is used throughout NATO and among allied nations to share track and tactical data between air platforms, and between aircraft, land and sea platforms or installations involved in the air battle. 

When Link 16 commenced its roll out in the 1970s/early 1980s it was revolutionary, with the TDL transmitting across an ultra-high frequency waveband of 960MHz-1.215GHz. The ‘secret sauce’ in Link 16’s approach is its Time-Division, Multiple Access (TDMA) approach.

In sharing its data, a Link 16 network will connect in turn with each link in the system, presenting new information as necessary while also providing a hub to which returning data can be assessed and further distributed. 

This ‘roll call’ is performed several times a second, however the approach has its limitations. 

There is a time lag, albeit small, between when participants can receive and exchange information. Essentially, they have to ‘wait their turn’ on the roll call. This can inhibit the TDL from acting in a true real time fashion which, given the speed of contemporary air operations, and their expected increases in velocity in the future, can have shortcomings. 

The other restriction is bandwidth. A Link 16 network typically handles data at rates of between 2.4kbps to 16 kbps. As a means of comparison, an average household wifi network handles data at speeds of megabits per second. Until now the TDL’s data rates have been adequate for supporting air operations. Nonetheless, the quantity of data which will be needed to support air operations in the future will only increase. 

The growing number of sensors hosted by aircraft, not to mention the so-called ‘Internet of Battlefield Things’ where platforms and weapons are networked as well as sensors, will trigger ever more demand for bandwidth.

One potential solution could be found in cloud computing. Israel’s IAI is one company which has developed cloud-based air operations command and control/situational awareness tools, as illustrated by its OPAL product (pictured). 

This can tie a host of air platforms together using only minor modifications to their conventional voice radios and TDLs allowing them to share information on a cloud. Such a network can grow and shrink organically according to the number of participants, and work in a real time manner, thanks to eschewing the TDMA approach. 

Moreover, significant increases in bandwidth can comfortably accommodate the exponential growth in data associated not only with air operations, but their counterparts in the land and sea domains. Link 16 certainly has several more years of service ahead, yet advances in cloud computing do offer a potential means to augment the TDL’s capabilities, possibly even replacing it one day.

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