SDR--the wave of the future.

Users of manpack and vehicle-mounted tactical radios are faced with two choices in how they communicate voice and data across the Tactical Internet. They can acquire the current generation single channel 'software-controllable' radios, which typically operate in a single frequency band and are often updated versions of familiar radios, or postpone procurement until the next generation of multi-channel simultaneous operation multi-band, multi-mode Software Defined Radios (SDR) become widely available.

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Any decision made today regarding the purchase of combat net radios will result in a twenty-year investment to say the least, as indeed radios have advanced considerably over the past two decades. In the 1980s radios could be described as: having an architecture that was largely hardware based, were reliant on a combination of Application Specific Integrated Circuits (Asic) and Digital Signal Processing (DSP), operating on a single frequency band and single channel only, offering few MIL-STD interfaces and having crypto algorithms that were hardware based and external to the set.

The 1990s saw the development of the software-controlled radio. These were specific to the company that had developed them and were not portable. Field Programmable Gate Arrays began emerging for the first time, gradually displacing Asic hardware. Single channel sets started to be fielded and these were also capable of operating multiple frequency bands, according to the operators' requirements. They had more flexible MIL-STD interfaces and for the first time included commercial standard serial port interfaces. Crypto for this class of radio remained hardware based but was finally embedded within the radio.

With the advent of the JTRS programme, developers moved away from vendor-specific software architecture to a common openly available architecture. This would enable the portability of waveforms across multiple radios irrespective of commercial origin through the JTRS Software Communications Architecture (SCA) 'common operating environment'. In addition to voice and data, sufficient bandwidth has become available to support video. Ethernet interfaces are now being incorporated in the sets. Asics have been entirely displaced in SDRs by general-purpose processors, and Crypto in SDRs, particularly in the case of the JTRS, has moved to embedded but now programmable chips.

Interest in the SDR is currently dominated by the high-volume US Joint Tactical Radio System (JTRS) programme, due to replace 750,000 radios in 30 families across the entire Department of Defense. Rather than dedicated specialised hardware solutions, SDRs exploit advances in software to manage the operation of the radio. The basis of the JTRS is the SCA, the radio equivalent to the 'PC' standard in computing, allowing large numbers of waveforms used by the Department of Defense to be stored as code within the radio and to be used when required. The initial acquisition of JTRS radios, Cluster 1, will see radios supporting 33 waveforms. Once expressed in this form and compliant with the SCA, these waveforms could be ported to each and every JTRS set ensuring that they are all interoperable and also backward compatible with the legacy radios they will initially supplement/support but ultimately replace. Multiple channel simultaneous operation, as well as multiple waveforms, allows one radio to replace multiple, single channel single waveform radios; saving space in often cramped platforms such as those found in the Army Aviation arena. Reducing radios also reduces costs. Although each unit is individually more expensive than typical radios today, the cumulative cost of the multiple radios that JTRS will replace is considerable. The JTRS Joint Program Office (JPO) estimates that the Air Force Tactical Air Control Party (TACP) will save over $ 300,000 alone with each vehicle it equips with a JTRS radio.

New Radios

Single-waveform, hard-coded radios are obsolete and will ultimately be replaced by SDRs. While this destination is not in any doubt, countries are taking different paths to reach the goal; balancing the need to replace their obsolescing equipment today with anticipating the potential of next generation performance several years from now.

As part of the Sincgars Omnibus Requirement Contract, America continues to buy large numbers of radios. Even though they are due to begin delivery of the estimated $14.4 billion (measured in FY02 Dollars) buy of 138,913 Cluster 1 radios in 2005, the United States continues to invest heavily in non-JTRS radios. In the presidential budget for defence this year there has been $ 45 million set aside to buy Sincgars to equip the National Guard. In addition, ITT has sold over 2700 of its export variant of the Sincgars, the Advanced Tactical Communication System, in the last twelve months.

But what ITT has discovered is that most Sincgars users want a "soldier's radio"--more power being the oft-requested element. In this vein ITT has continued development of its initial Suo Sas (Small Unit Operations Situational Awareness System) programme, recently renamed Slice (Soldier Level Integrated Communications Environment), to include the production of the first useable soldier waveform. As the primary deliverable of the Slice programme, the first completed Soldier Radio Waveform should have been delivered to Cecom by the time these lines are read. For the Slice programme, ITT has received a nine million dollar contract modification for 2004, which has fuelled an extension through 2006--at which time a third software release is expected.

France, like America, is pursuing an advanced SDR programme while also acquiring new radios based on current technology. In 2004, Thales will deliver the first PR4NG--known commercially as F@stnet radio--to the French Army. This 30 to 88 Mhz-band VHF radio has output power selectable up to ten Watts and a 64 Kbps ECCM waveform.

Several other countries in Europe are also in the process of acquiring radios. Finland has recently acquired the Tadiran Communications CNR9000 VHF and HF radio. The company is expected to announce the increase of its throughput from 32 kbps to 64 kbps during this year. Tadiran also has an agreement with the Danish company Terma to market the radios in Scandinavia and elsewhere in Europe. Denmark is also to publish details for its CNR requirements in early 2004. Last year Hungary joined Norway in selecting the Kongsberg MRR and Bulgaria is deploying Harris Falcon II radios as part of the Marconi Selenia primed Field Integrated Communications and Information System programme.

Multilateral interoperability also has its part to play in procurement. Large numbers of countries have selected new radios to support their activities, with Harris being particularly successful in winning Nato Partnership For Peace (PFP) related communications projects, with its Falcon II family. ITT reports that Sincgars has been selected by Uzbekistan, Latvia and the Czech Republic for PFP.

ITT will have received news of the first successful trials of its Spearhead handheld radio from a "former Eastern European" nation by the time this issue goes to print. The Spearhead is the company's new Sincgars and JTRS compliant secure radio offering two Watts of operating power that, as a result of field trial inputs, is to be boosted to five. The modular unit can be dismantled into three user-changeable parts: interface, frequency module and battery. Interestingly, the company is finding that the market for the Spearhead is steadily defining itself, with Special Forces and paramilitary groups finding faith in its capabilities, although initial trials with one African nation were for border patrol applications. The Spearhead offers 2320 channels with single-channel and frequency hopping modes, operates within the 30 to 88 MHz bandwidth and is software reprogrammable.

Others are actively pursuing software radios. Sweden has embarked on an over-arching project to renew their military communications structure post 2010. To this end it has signed agreements with the JTRS joint programme office on implementing the tetra waveform on the Software Communications Architecture and has used US-supplied radios including the Rockwell Collins Talon to explore ad hoc networking. It is also pursuing a tactical level SDR procurement through its CTRS (Common Tactical Radio System) programme, which is due to enter service after 2007.

Sweden is also a customer for trial numbers of the Rohde & Schwarz M3TR, reportedly the first single-channel SDR on the market. The M3TR, manufactured locally by the company EID, is in service with Portugal and has also been exported to Belgium and Brazil.

Finland also has a development programme due to deliver Army and Navy SDRs from 2009.

France is currently pursuing three SDR activities: the Wide Band Waveform (WBWF) demonstrator, the Multimode Multirole Radio (MMR) and the future Software Architecture. The goal is to use these projects to develop and field a wideband software defined radio, the 'PR2', potentially using the JTRS SCA, by 2010. Work on this project is being led by Thales and supported by Raytheon in the area of incorporating the software communications architecture.

A hybrid approach is being explored in some countries with incremental acquisition of SDRs in conjunction with other system procurements. Belgium's Bams system is due for replacement around 2012 to 2015. Consideration, however, is being given to acquiring a new SDR in the 2007 to 2008 timeframe, for installation on new armoured fighting vehicles. A similar approach is being discussed in Britain with the Future Rapid Effects System programme. Separate to this, the JTRS JPO has said Britain would acquire Cluster 1 vehicular JTRS radios through Foreign Military Sales.

In East Asia there are a number of radio opportunities; perhaps most significant are South Korea's Force Integration Project 216 to replace its license produced AN/PRC-77/VRC-12 VHF inventories and the Po-Sheng joint digitisation programme in Taiwan. Japan is in cooperation with the JTRS joint programme office Software Radio Co-operative Research Programme and, with Raytheon's support, is funding NEC to develop a wideband and narrow band software communications architecture SDR. ITT reported adding new customers for its ATCS product recently in the Middle East.

Backbone Radios

While tactical nets are using VHF and HF sets to support soldiers in the field, greater demands for data are leading to the introduction of higher capacity wideband UHF 'backbone radios'. These offer considerably more bandwidth than the 16 to 64 kbps and 4.8 to 9.6 kbps offered by today's VHF and HF radios.

Two American manufacturers today dominate the market: Raytheon with the RT-1720(V) Enhanced Position Location Reporting System(EPLRS) which is being fielded with the US Army and Marine Corps, and ITT with the Mercury radio, which is in service with the US First Digitized Corps and 2nd Brigade of the 265th Air Defense Artillery as the Near Term Data Radio. The Mercury was also selected by Britain as part of the winning General Dynamics solution to provide the Bowman High Capacity Data Radio (HCDR) requirement. The data rate for the HCDR is 1 Mbps, while that of the Mercury NTDR is 360 kbps and the EPLRS is up to 525 kbps.

The United States uses the 250 Mercury radios it ordered in 1998 and a further 324 it had contracted in April 2003 to support inter Tactical Operations Center communications. Britain has opted to embed its 3400 plus HCDRs across its tactical Internet with approximately one in six Bowman-equipped vehicles fielded with the HCDR. Several other countries including Canada, Germany, The Netherlands, Sweden and one unnamed in Asia have acquired the Mercury for trials. Canada, who has taken approximately 40 Mercury radios, is also considering upgrading its Iris tactical communications system--on which General Dynamics based its Bowman solution--and is eyeing a possible wideband upgrade. Raytheon has delivered 10,000 of the 12,900 EPLRS systems ordered against an Army Acquisition Objective of 33,000. A third wideband system manufacturer, BAE Systems North America, is also reporting interest amongst several US and international customers in reference to its 1300 to 1500 MHz, 19-channel backbone solution--the AN/VRC-99A wideband radio.

JTRS

Two of the JTRS programme clusters address the requirements of tactical vehicle mounted and manpack radios: Cluster One provides three and four channel radios and Cluster 5 is responsible for providing manpack, handheld and embedded radios.

The Cluster 1 contract, valued at up to $ 856 million, covers the System Development and Demonstration and Low Rate Initial Production (Lrip) for the Cluster 1 radio. It was awarded in June 2002 and won by Boeing Integrated Defense Systems in competition with a Raytheon-led consortium. The Boeing team comprises TRW Tactical systems, Rockwell Collins Government Systems, BAE Systems Communications and Harris RF Communications. Full rate production is due to be awarded in late 2007/early 2008. It is at this point that the Department of Defense has reserved the right to reopen competition for the production of Cluster 1 sets. FMS exports of the radio are expected to start from 2009. Cluster 1 will initially equip US Air Force TACP parties, Army and Marine Corps vehicles initially prioritising FCS units and Army Aviation helicopters.

In June 2003, the JTRS joint programme office launched the JTRS Cluster 5. This Cluster will provide handheld, manpack radios and embedded Small Form Factor (SFF) sets--designed to cope with the difficult size, weight and power constraints in systems ranging from the Land Warrior to the Joint Direct Attack Munition. An award is scheduled for as early as February 2004 although industry expects this to slip into the Spring. Over 165,000 radios are required: 73,000 handheld, 44,000 manpack radios and 47,000 SFF embedded radios. A General Dynamics Decision Systems team that includes BAE Systems, Rockwell Collins, Thales Communications. Motorola, Vanu, Agile Communications, Altera and RedZone Robotics are competing against ITT, Boeing and Harris who form 'NetForce 5'.

As an aside, JTRS Clusters 3 and 4 have been merged and renamed AMF--Airborne Maritime Fixed--signifying the programme's airborne forces and naval affiliations.

Special Operations

Special Forces requirements for communications place great emphasis on autonomy, intra-team communications and a Beyond Line of Sight (Blos) capability. Unlike conventional forces, Special Forces do not have the advantage of having repeater nets or other infrastructure to support operations. Autonomy is perhaps the defining characteristic of Special Forces, and radios have been developed to meet this need. In the 1990s, multiband, multimode radios (MMR) began being fielded to the black shirt forces, offering coverage in a single radio across HF, VHF and UHF frequency bands. Thus eliminating the need for the soldier to carry multiple radios.

The United States Socom (Special Operations Command) manpack radio inventory largely comprises the Harris AN/PRC-150, the 30 to 512 MHz AN/PRC-117F and the Raytheon MBMMR.

The distinction, however, between Special Forces and conventional requirements for communications is becoming blurred. One of the lessons the US has taken from operations in Iraq is that the move to operate with fewer conventional forces on the ground has meant a greater need for Special Operations-like Blos capabilities. The need tends to lean toward HF, but also for a UHF tactical satellite link, for fast moving columns that outrun their support infrastructure. To illustrate the adoption of Socom radios by more conventional forces, during the recent assault on the al-Faw Peninsula the Royal Marines used AN/PRC-117F radios to operate with the US Marine Corps.

Miniaturisation 

The use of commercial off-the-shelf technologies in the cellular TDMA has enabled commercial trends in miniaturisation. With the exception of the modern RF electronics, the radio is now software based with the previous Asics and functionality replaced with FPGA programmable logic. Opening up the EPLRS green box today would show it to be largely empty. The US Department of Defense has not, however, opted for a smaller box, as this would require the expense of redesigning rack and vehicle installations. Nonetheless, Raytheon has subsequently privately developed the EPLRS Lite--shown for the first time at Eurosatory 2002--and more recently the cigarette-pack sized EPLRS Micro-Lite, launched at the December 2003 Signal Symposium. Both use the common software framework of the standard EPLRS, giving them the same inherent capabilities although using a five-Watt battery powered RF amplifier. The signal power, however, is more limited than that available to the standard EPLRS using the vehicle power supply.

Jerk and Run

Vehicle installed radios may be required to decouple from a disabled vehicle and operate in the dismounted role. In the JTRS Cluster 5 requirement there is a need for a Vehicular Interface Unit allowing the product to be mounted in the vehicle while maintaining a capability for battery based operations 'jerk and run'. This enables the user to have backup mobility while taking advantage of vehicle powered RF amplification to increase the effective signal power. While the jerk and run requirement is important manufacturers are also concerning themselves with bringing handheld radios into vehicles and incorporating them in to the vehicle system. Thales Communications has matched the handheld 5-Watt AN/PRC-148 Multi-Band Inter/intra-Team Radio (Mbitr) with a 20-Watt frequency-hopping power amplifier. Into this the Mbitr (pronounced <<Em-biter>>) can be inserted and removed when the user enters and leaves a vehicle. With the addition of a further power amplifier it can also function as a repeater station to expand the range of other radios.

New Technologies

Software technology has not impacted the RF portion of the radio, but new development is pushing that same Radio Frequency technology forward. Under the Department of Defense's Challenge Programme, the US company Hypres is developing the All Digital Receiver (ADR) for applications across the JTRS programme, potentially including a technology insertion for Cluster 1. The ADR would replace silicon-based analogue to digital converters (ADC), using Rapid Single Flux Quantum technology running on cryogenically super-cooled, programmable and digital super conducting ADCs. This promises to more than double the number of simultaneous channels in the equivalent silicon-based form factor--decreasing heat dissipation and cost and further reducing the need for individual radios.

Frequency management under the Darpa XG programme is also an area that could be improved. Darpa found that only 15 per cent of the frequency allocated to users in the densest part of the Washington DC area was used at any one time. The average usage in the metropolitan areas they tested was six per cent. The XG programme team believes that in the future dynamically controlled localised spectrum management could provide a ten-fold increase in efficiency, with applications for both the military and civilian users.

At the local level, Combat Net Radios (CNR) are programmed to give voice priority over data, temporarily interrupting the dataflow. The growth of data on the battlefield has outstripped voice requirements and militaries are now exploring ways of ensuring that voice communications are always available while maintaining data communications. The US Army Cecom (Communications Electronics Command) is currently funding development by ITT of the SIVD (Simultaneous Independent Voice Data) mode, which allows the user to carry on voice conversation simultaneously with data routing through the radio. A new vocoder enables voice communication to take up only 4 Kbps as opposed to the 16 Kbps in previous vocoders. This leaves 12 Kbps available for data transmission. Signed in 2002, development work is nearly complete and the waveform will be rolled out in the very near future. Reflecting today's software controlled architectures it can be provided as a software upgrade to all SDR radios that are fielded. A similar facility is also included in the Thales PR4G F@stnet radio.

All Told

The SDR is the undeniable future for radio communications; manpack, vehicle-mounted or otherwise. The flexibility in their use of waveforms, multi-channel operations and improved bandwidth are a significant boost to battlefield-networked effectiveness. They will also provide the basis of joint but not international interoperability. Having the same waveform is not the same as having the same crypto, which is the type of interoperability this level requires.

A Comparative Selection of Handheld Radios

Tadiran CNR-9000
Frequency Range [MHz]                    30 to 108
Data Rate [Kbps]                                32
Power Output                         5 to 50 Watts
Dimensions [mm]                     227 x 245 x 87
Weight                                      3.1 kg

Notes: In service with Finland, upgrade to 64 Kbps
expected shortly

Thales Comm. PR4G F@stnet

Frequency Range [MHz]                     30 to 88
Data Rate [Kbps]                                64
Power Output                              10 Watts
Dimensions [mm]                     259 x 181 x 79
Weight:                                       3 kg

Notes: Due to enter French service in 2004

ITT Mercury UHF (HCDR)

Frequency Range [MHz]                   225 to 450
Power output                           1, 3, 5, 20
Dimensions [mm]                   2754 x 138 x 381
Weight                                     11.4 kg

Notes: In service with USA (NTDR), UK (HCDR/
VRC-340) plus five trial countries

ITT ADR+

Frequency range [MHz]                     30 to 88
Power Output                 1 mW, 0.1, 5 and 16 W
                          (16 with second battery)
Dimensions [mm]                     88 x 185 x 234
Weight                     4.5 kg with one battery

Notes: Basic CNR for UK under Bowman designated
PRC-355

Harris AN/PRC-117F

Frequency Range [MHz]                    30 to 512
Data Rate [Kbps]                                64
Power Output                         1 to 20 Watts
Dimensions [mm]                     343 x 267 x 79
Weight                                      3.5 kg

Notes: SF radio in service with US, UK, Canada, New
Zealand, Germany and Poland

Rohde & Schwarz M3TR

Frequency Range [MHz]                   1.5 to 108
Data Rate [Kbps]                                64
Power Output                     0.001 to 20 Watts
Dimensions: [mm]                    117 x 74 x 308
Weight                                        5 kg

Notes: First SDR on the market

ITT Spearhead

Frequency Range [MHz]                     30 to 88
Power Output                    2 Watts, soon to 5
Dimensions [mm]                      155 x 65 x 45
Weight:                                  500 grams

Notes: First trials results by end Feb 2004

Raytheon EPLRS Microlite

Frequency Range [MHz]                   420 to 450
                        (optional band extensions)
Data Rates [Kbps]                      57/6 to 525
Power Output                     5 Watts w/battery
Dimensions [mm]                      128 x 70 x 26
Weight                  450 grams w/o power supply

Notes: Launched Dec. 2003 at Land Warrior market

Harris RF-5800H Falcon II

Frequency Range [MHz]                    1.6 to 30
Data Rate [Kbps]                               9.6
Power Output                       1, 5, 20, 100 W
Dimensions [mm]                     267 x 81 x 343
                                 incl. Battery box
Weight                        4.5 kg incl. battery

Notes: Integrated GPS in British Bowman solution,
in US services as AN/PRC-150