Naval Forces' Capability for Theater Missile Defense (2001) / Chapter Skim
Currently Skimming:
Appendix B: Analysis of the Capabilities and Limitations of Link 16
Appendix B: Analysis of the Capabilities and Limitations of Link 16
Pages 151-158
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 151... ...
The messages include surveillance tracks, weapons coordination, air control, target information, PPLI, and even digitized voice networks. JTIDS radios or their MIDS variants will be installed on a variety of aircraft, surface ships, and submarines over the next 7 years, as well as in Patriot and THAAD forces.
|
From page 152... ...
Welch, LCDR David, USN, "U.S. Navy Tactical Data Links," briefing to the Tactical Network Panel of the Committee on Network-Centric Naval Forces on February 17, 1999, Command and Control Systems Directorate, Office of the Chief of Naval Operations (N62G)
|
From page 153... ...
In this, the most complex mode, all terminals share a single pool of time slots, as is also true for contention access. Rather than transmit at will, however, the terminals perform a distributed algorithm to apportion the time slots.
|
From page 154... ...
Since JTIDS divides its available L-band spectrum into 51 channels, the extreme upper bound on the number of bits per second that can be transmitted simultaneously from all JTIDS terminals in a tactical arena is 51 x 115,200, or 5,875,200 bps. This assumes that all available spectrum is devoted to JTIDS, that all terminals use the maximum possible data rate, and that all time slots in all channels are used for transmission, and it ignores the overhead of housekeeping bits.
|
From page 155... ...
/TacLink weapons Incremental increases in the flexibility of Link 16 networks, perhaps coupled with greater ease of planning and configuring for such networks Higher bandwidth communications across Link 16 radio channels More accurate relative position and time information for Link 16 platforms Increased ability to transmit J-series messages across non-JTIDS radio channels Gateways between Link 16 radios and their messages, on the one hand, and the Army's messaging system on the other Tactical command and position/location links to guided munitions B.2.1 Dynamic Network Management System for Link 16 These are a set of interrelated changes to the JTIDS channel access protocols that should allow more flexible use of JTIDS networks. Key technical features are improvements in the methods used for late net entry, for reallocating time slots as demand changes, and for varying the throughput rate dynamically.
|
From page 156... ...
Maximum rates for wireless communications are usually achieved only for stationary objects that are quite close to each other in a clear RF environment, because performance degrades quickly with Doppler effects, distance, and interference. Since JTIDS is generally employed between mobile platforms across relatively long distances, the actual data rates may be well below maximal.
|
From page 157... ...
The proper solution and one that has been universally adopted in the commercial communications world, both in the Internet and in all telephone technology, for decadeshas been to use a layered protocol stack so that any type of message can flow across any type of communications medium. Rather than sort out how J-series messages should be conveyed across any type of medium, these programs are attempting minor incremental "kludges" to work across satellites and so on.
|
From page 158... ...
On the other hand, JTIDS provides a poor starting point for this concept, partly because JTIDS networks have proven extremely difficult to plan and configure, but mainly because thus far JTIDS radios are extremely expensive. It is certainly possible that both problems could be overcome, but the solution would certainly be much easier if a different starting point were adopted.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.