Tactical Data Links Over Copper (DON10) ‐ simple and effective fibre ‐ optics alternative ‐ Alec Umansky Ian Thomas (MAJ Retired) Christoph Zuber ......................... Defence Communications Industry P/L DMO, JP2077 2B.1 ............................................. Melbourne, Australia Laverton, VIC Christoph.Zuber@ defence-comms.org alec.umansky@defence ‐ comms.org ian.thomas@defence.gov.au Tel 03 9523 9211 / 0417 501 510 This paper presents an innovative approach for tactical data links – developed in close collaboration with the Australian Army Signal Corps RASC, with the objective of overcoming the problem of fibre ‐ optic cables’ propensity to damage in the field. The result of this successful collaboration has led to the development of a field deployable communications product that uses copper cables (DON10 type) as its communications medium and is capable of extending data over 8kms at bandwidth of up to 60Mbs – a simple to use, secure and effective alternative to the fibre ‐ optic cable based systems, especially on a brigade level and below. The paper reviews the ‘off the shelf’ transmission technology and its adaptation for Defence, resulting in a versatile data link system for field deployed environment in military. Technical and logistical advantages of using copper wires in modern data applications are presented, including the Australian Army’s report of the early field trial. This collaboration and the resulting product won the AFCEA ‘Golden Link Award’ as well as a number of other prestigious industry awards for its outstanding innovation. Keywords: shdsl, transmission, bandwidth, data links, DON10 Introduction Yet another practical problem with FOC is that they are often impossible to roll ‐ out in difficult terrain e.g. in Rapidly deployed, simple to use, effective and reliable earthquake recovery operations, mountainous terrain, communications are vital in modern military operations. tunnels and similar harsh environment. Wireless The area of data tactical links and the so called ‘ad hoc’ technologies are often difficult to use in these locations networks requires equipment providing high bandwidth due to signal reach i.e. lack of direct line of sight and data transfer while being simple to install, operate and sometimes due to security constraints. repair. Invariably this equipment needs to be capable of With these concerns as its background brief, the a wide range of applications. Australian Army started to research alternative The commonly adopted standard in tactical data technologies that could alleviate FOC field deployable networks is the use of the fibre ‐ optic cables (FOC) problems. One technology that stood out was ‘DSL’ ‐ offering secure signal propagation and high bandwidth. transmission signal modulation specially designed for However, FOC have a propensity for damage, especially the delivery of internet and other data services over when used in areas of high troop and machinery telephone copper cables. This ‘dsl’ technology movement. This is particularly relevant to the ‘rear promised the use of common ‘field wire’ or WD ‐ 1/TT echelon’ or Troop Support Elements where FOC damage type steel reinforced copper wire in place of FOC in is a regular occurrence due to it being bent or torn. specific environments – most commonly, on a brigade Inherent to fibre ‐ optic networks is difficulty and often or below levels. impracticality to repair the damaged fibre ‐ in the field. Rationale for using copper cables (or ‘DON10’ as it is A compounding problem occurs when logistics troops known in Australia) was that the technology promised relocate (every few days) thus increasing recurrence relatively high bandwidth over distance, but more fibre ‐ optics outages, repairs, and associated costs. importantly, copper cables offered a ‘soldier friendly’ Page 1 “Tactical Data Links Over DON10” Defence Communications Industry Pty Ltd
transmission medium that even when damaged, could easily and quickly be repaired by soldiers and without REDEFINING A STANDARD IN TACTICAL DATA LINK special tools. WHY GO BACK TO COPPER? The general skepticism towards use of copper cables for ADAPTING DSL TECHNOLOGY FOR MILITARY modern data communications is historical. Copper cable APPLICATIONS and its field wire military variant have been used as a The key characteristic of an ‘off the shelf’ public telecom basic means of data and voice communications since DSL technology is that it is specified in two main before the First World War. Morse code transmission, variants: exchange (or switch) based modems and voice telephony or signal wire applications are the most customer premises based modems. Effectively, this common associations. Its use in modern corresponds to two types of equipment with different communications ‐ at least until now ‐ has been power and infrastructure requirements and thus perceived as archaic. restricts its use in portable deployable applications. In Transmission technologies used in today’s armed forces addition, chipsets performing signal (data) modulation for voice and data links are predominantly fibre ‐ optic are different at each end of the transmission and thus cable and satellite based. However, when transmission further restricts equipment configuration and more systems are used in a tactical environment, two importantly, its bandwidth flow. important disadvantages of using fibre ‐ optic cables The first challenge therefore in adapting an off the shelf (FOC) are overlooked: (1) FOC tendency to damage due dsl based equipment is redesigning its exchange and to troop movement and heavy machinery operation, (2) customer premises delineation. A programmable line inherent difficulty of repairing FOC in the field. interface or Master/Slave configuration is the first step DSL transmission technology allows copper cable to be that opens dsl to be used as portable field deployable used as a modern and relatively high bandwidth communications products. communications infrastructure and Australian Army has The second design challenge is selection of the suitable led the way in this technology adaptation for its transmission modulation (as defined by CCITT ‐ public requirements. telecommunications standards governing body). The The three important factors in considering this DMT (or Dual Multi ‐ Tone) modulation was determined alternative by the Army were: to be well suited for the field deployable environment (1) a significant cost reduction (by a factor of x20) in due to its noise immunity whereby the signal and the using copper compared to FOC effective bandwidth is modulated in multiple frequency (2) the ease of copper cable roll ‐ out and retrieval and carriers (up to 300) with each carrier being tested and (3) the ease with which copper cable can be repaired: then monitored for bit ‐ error ‐ rates, signal ‐ to ‐ noise ratio “as easy as tying shoelaces”. and other electrical parameters. Other significant issues with FOC are: its size and Once transmission issues weight, as well as difficulties with were clearly defined, the its roll ‐ out and retrieval. remaining design concerns In short, it was felt that “the old are typical of other portable DON10 could be reincarnated”. field deployable devices: battery backup power, EARLY TRIALS SUCCESS rugged carry case, dust and The first functioning prototypes of moisture proofing. tactical data modems using Rate Within a relatively short Adaptive DSL technology were period of six months a trialed in a field deployed logistics number of functioning environment during ‘Crocodile prototypes were built for West’ Army exercise (see also trials by the Australian Army Field Trial Report pg.5). The Army. The trials were a equipment viability was proven resounding success proving within the first two days of the conclusively the exercise when FOC links were effectiveness of DSL inadvertently damaged and the technology and establishing main data link between the two grounds for actual product development. Page 2 “Tactical Data Links Over DON10” Defence Communications Industry Pty Ltd
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