Accelerating Instrumentation System’s Closure of Live Training’s Capability Shortfall

Historically ground live collective training using laser-based weapon effect enables simulation of 40% to 50% of a unit’s combat capabilities.  Technology advances now allow the inclusion of higher echelon capabilities (e.g. Intelligence Surveillance Reconnaissance, Indirect Fire, Logistics) plus ability to sense, see and engage Computer-Generated Forces (CGF) in the Live domain, closing that training deficiency.   This next generation training technology requires a paradigm shift in data rates and opportunity for consolidation of previously separate (manoeuvre / event / CGF, audio, video) streams into one media.   In this paper we evaluate communication system requirements necessary to support next generation training, focusing on a 3G Partnership Project (3GPP; 4G, 5G) network. We present our analysis in a three-part framework.
     
Firstly, training requirements and their derived communication requirements are presented and underpinned by a comparison of alternative data transportation mechanisms. Secondly, a communications model defining individual trainee’s data is presented.  Modelling considers media requirements by unit size and training objective to further demonstrate life cycle cost of delivering each system at the tactical edge on a global scale.

Live training delivery spans expansive, austere, congested, complex, contested and cluttered environments.  Therefore, our third perspective will utilize propagation modelling to compare current range infrastructure with 3GPP.   The comparison is relative, noting the introduction of laser-less, Non-Line-Of-Sight (NLOS), CGF, Augmented Reality (AR) and on-board analysis increases communications and computation requirements at the tactical edge. Our evaluation extends to the consideration of public / private spectrum utilization and multi-national interoperability.

Future ground training capability evolution has the potential to be significantly constrained through insufficient instrumentation and this paper will analyse how the critical enabling bandwidth, latency and augmented reality entity implications can be met through the incremental transition from a narrow band to a 3GPP network. 
 

INTRODUCTION    

Collective training provides a mechanism to facilitate realistic combined arms, joint, inter-agency and multi-national training most often at Platoon to Brigade level.  Exercise objectives are the employment and performance assessment of units and their commanders, in complex, representative force on force tactical environments.    Collective training for larger units often has requirements for scalable multi-domain (land, sea, air, cyber, space; live, virtual, constructive) effects and a multi-national construct.    

 

Historically, training range austerity and scale (as Table 1), medium-high entity count, low data rates, and asymmetric download/upload data streams led to the development of purpose-built communications architectures.  These bespoke training and technology specific network architectures provide Simulated Area Weapon Effects (SAWE; e.g. minefield, artillery, etc) plus near real time reporting of Live entity manoeuvre and direct fire laser engagement activity.   

To meet the parallel instructor and safety requirements, specialist collective training networks have incrementally evolved around proprietary instrumentation by superimposing additional, parallel voice and/or video/data communications networks onto the training data network.  This traditional approach historically and currently delivers collective training across many Tier 1 military nations.

The 2020 decade will see exponential demand in network capability growth in collective training.  Transition from laser to laser-less (geometric pairing), non-line-of-sight (NLOS) weapon effect simulation and emergent Augment Reality (AR) are critical enablers for enhanced Live, Virtual, Constructive (LVC) simulation integrated into contemporary Live training as illustrated in Figure 1.

Legacy communications networks primarily reported manoeuvre and direct fire outcomes where the complex contemporary operating environment requires a training Network to support: 

a)    Increased realism, through tactically deployable virtual sensors, weapons and effects (e.g. Synthetic Wrap); computer generated forces (effects, entities; visualised in Augmented Reality), and representative geometric pairing of capabilities when they cannot be represented by lasers and/or tracking;

b)    Enhancing objective performance assessment, from individual to unit & commander, utilising multimedia data streams which require increased, time sensitive data capture, analysis, communication and readiness evaluation;

c)    Safety overlay, dynamically monitoring soldier/vehicle safety using real-time training exercise data (e.g. heat-stress, vehicle Health and Management System (HUMS), geo-templating, live-fire templating, Casualty Evacuation (CASEVAC), manoeuvre conduct, etc).

 

 

FUTURE DATA STREAMS AND DATA SETS

The ability to route multimedia data to and from Live trainees at the tactical edge was not envisaged nor easily achievable two decades ago when Live Combat Training Centres (CTCs) first deployed as an overlay to (often in-service) laser-based force on force engagement systems.   Today multimedia communications (e.g. 3GPP) are prevalent and allow enhanced data communication to and from all tactically deployed Live entities as shown in Table 2.  Key data sets in this table are:
•    Traditional tactical status and location (Time, Space, Position Information (TSPI)) augmented with posture, orientation, etc plus rate of change information;
•    Biometrics, audio (e.g. intra-section radio) and video (e.g. body or headcam) are new data streams for increased readiness evaluation and/or reduction in training infrastructure;
•    Geometric pairing weapon effects simulation and AR visualisation are emergent data streams allowing seamless inclusion of (virtual, constructive) CGF, limited today to sensor stimulation (e.g. Synthetic Wrap).
Data stream’s Quality of Service (QoS) assignment shown in Table 2  reflects the immediacy of weapons effects and observation data and lower priority on audio & video.  

A unit’s size, training objectives, and analytical tools / requirements influences the usage of Table 2 data streams; i.e. Brigade and higher formations focus on intelligence, surveillance, target acquisition, and reconnaissance (ISTAR) ‎[2], indirect/precision fires ‎[3] and logistics whereas a smaller unit will focus on the direct fire battle and (urban) video monitoring.  Applying empirical (authors’ experience) factors to Table 2 data streams result in network up-stream / down-stream capacity by Unit of Figure 2.

A contemporary Combat Training Centre’s increasing appetite for objective analysis demonstrates a clear requirement for richer data sets and increased meta-data as a key enabler.  The Table 2 highlights are as follows:
•    Consolidation of previously individual networks;
•    Increased information capture driving exponential growth in communication demands; e.g. legacy ‘location’ is now location & orientation with rate of change, etc;
•    Increased real-time audio & video capture in conjunction with a paradigm shift from wired urban training video to wireless, however, it should be recognised that video data dominates network volumes and demands edge processing to apply QoS requirements.

A second parameter defining (3GPP) base station capacity is the number of ‘connected users’, which for training requirements of Table 2 plateaus at approx. 500 (Battalion-) entities.   This design parameter is defined from manoeuvre expectation for likely entities within a multi-kilometre, 120o sector.   It should be noted that peak entity density (connected users) may be exceeded during concentrated activities; i.e. issue, in-briefing, After Action Review (AAR) and receipt albeit with lower communications (latency, capacity) requirements during those periods.

Future data dependent collective training will, by necessity, expand the type and volume well beyond the capacity of current collective training data streams.  The resulting high network capacity can be managed through prioritisation of media QoS, reporting rates, edge processing and noting selected data stream employment versus unit scale.     The following subsection considers collective training physical communication media alternatives.
 

ALTERNATIVES

Previous doctrine and historical lessons drove the requirement for a direct fire training capability that could meet the needs of the Infantry / Armour Combined Arms battle.  The contemporary environment has changed dramatically, and the victor is more likely to be decided by their command of the electromagnetic spectrum, precision fires and tempo derived from real-time shared situational awareness.

Direct fire training capability traditionally used system specific networks based on low-data-capacity, medium-latency, medium-high player count and nationally assigned spectrum.    These solutions continue to deliver effective training but their limited capacity and use of proprietary protocols preclude further capability growth and/or advancement into a contemporary multi-domain training ecosystem.   Furthermore, multi-national interoperability can be challenging across nationally assigned spectrum and lack of endorsed international standards.  Clearly these points are only amplified by the timing of individual nation’s training system acquisition activities.    

Collective training communication alternatives include the following:
1.    Narrow-Band, expanding legacy multi-network architectures supporting direct fire laser engagement plus indirect fires (e.g. platoon / company mortars; small geometric pairing fleet) with separate voice and data / video, but remains lacking a ‘standard’ basis and consequently is funded as a bespoke architecture.
2.    Battlespace Communications, utilising an existing media although coverage, capacity, security and configuration control considerations limit flexibility compared to a purpose-built training network;
3.    3GPP (4G, LTE, 5G, etc), as proven Commercial Off the Shelf (COTS) standard, noting constraints on spectrum availability and propagation ‎[4]‎[5];
4.    Low Earth Orbit Satellite (LEOS) plus terrestrial (mesh, star) nodes, representing an infrastructure-less communications media, albeit foliage, size and Radio Frequency (RF) safety considerations require the secondary terrestrial network.
5.    Mesh Networks, with advantages of little to no fixed infrastructure but lack assured real time communications to all Live training entities.

The alternate physical media above ideally host consolidated training data streams of Table 2 in volumes of Figure 2.   From the alternatives, 3GPP represents an endorsed global standard, supporting multimedia communications typical of collective training.   3GPP provides flexibility, synergies with emergent device protocols (e.g. Bluetooth Low Energy (BLE), Wi-Fi; i.e. biometrics, AR) and scalable infrastructure requirements from Home Station using Network Operator to a bespoke network in an expeditionary training or operational theatre, as described in subsequent subsections. 

Network Operator 3GPP Infrastructure

Mobile Network Operators own or control access to licensed radio spectrum and elements of the network infrastructure necessary to provide subscriber services over licensed spectrum.   Here Network Operators are envisaged to provide complete or complementary Defence training coverage at a cost in both revenue and security terms. 

Network Operator’s coverage primarily addresses areas of revenue / population density, potentially overlapping Home Station training sites but less so remote training areas.  In this latter case training area coverage can be provided by a Network Operator while noting life cycle cost model review of Network ownership versus 3GPP as a Service.   Network Operator engagement is required to ensure adequate coverage, prioritisation and base station connected user capacity for collective training. Increasingly Network Operator planning will include multi-national training activities.      

Although not directly a topic of this paper, hosting defence training data streams on public networks requires communication security measures for which established standards and validation methodologies exist.   Cyber resilience in the face of potential adversaries that routinely exploit offensive electronic warfare below the threshold of warfare ‎[6] is a baseline requirement and is a common issue which a Network Operator of a public or private network must address effectively.    

Dual (Public, Private) 3GPP

Private 3GPP networks have advantages of frequency agility, additional network cyber measures and management of network entities.  Private networks may be hosted either in traditional 3GPP bands using Defence managed spectrum and network installation separate from a traditional Network Operator and/or in non-traditional spectrum.  

Non-traditional spectrum supports the 3GPP standard but in spectrum other than standard 3GPP frequency bands.  For example, a fielded non-traditional spectrum example utilises NATO bands E and F (S-band).  The term ‘non-traditional spectrum’ here is different from 3GPP (5G) use of unlicensed spectrum, where in that unlicensed spectrum case uncertainty remains on assured connectivity at scale and multi-national environments.

For majority of training, dual public / private Networks are favourable allowing Defence greater Network autonomy within their site(s) plus the additional flexibility afforded by domestic and international roaming autonomy.  Use of non-traditional bands provides further expeditionary flexibility and value for money in exercising seamlessly off and on Defence training areas without the need for additional network infrastructure.    In all cases communications are 3GPP standard, maximising the value of the exploitation of an open, participative, platform and network infrastructure.

COMMUNICATION SYSTEM FIELD EMPLOYMENT

3GPP has significant advantages in global deployment and multimedia communication.  This section considers its employment in typical training ranges and compares infrastructure to legacy narrow band (i.e. UHF, VHF; low data rate) systems.  System factors such as entities at range (i.e., poorer link margin) being afforded lower data rates than those closer to a base station become important. In this regards we note the transition from laser to laser-less weapon effect simulation, employment of AR and in-field virtual sensors significantly enhances realism but places more stringent requirements on the communications system.

Spectrum

Readily available and affordable spectrum allowing global exploitation is required to enable Users freedom of manoeuvre in conducting joint and multi-national training.   3GPP offers that flexibility albeit spectrum is Government and/or Network Operator managed/owned.  Realisation of a 3GPP training network is via Network Operator and/or privately managed network in either traditional or non-traditional spectrum as described earlier.

Propagation modelling discussed in the following subsection considers 700MHz (Band 28), 2.6GHz (Band 7) and S-Band (2GHz) as two traditional 3GPP global roaming and one non-traditional band respectively.  Propagation will favour 700MHz and remote austere ranges potentially allow its use. Higher frequency bands are included herein for comparison.

Exploitation of 3GPP 5G (mmWave) bands may find utility in urban training facilities given potentially shorter propagation distances and increased video data streams.  Propagation limitations of the higher frequency 5G (mmWave) bands render it suboptimal for rural or austere CTC training.  

Range Propagation 

Laser engagement weapon effect simulation operates optically and does not require RF communications coverage.  In such legacy laser engagement ranges 95% to 97% training area coverage is typical.  Weapon effect simulation via geometric pairing with augmented reality visualisation of computer-generated forces requires low-latency dependent RF communications, requiring (say) 99.5% training area coverage.   Table 3 presents actual training areas comparing quantity of base stations required with legacy (UHF, VHF) communications at 95% coverage, 3GPP at 95% coverage and secondly 3GPP at increased 99.5% coverage.   

Note 1: In this range terrain and foliage preclude economic terrestrial only solution; aerial alternatives are deployed but not considered in this analysis.

Table 3 illustrates 3GPP has higher base station requirements than legacy (VHF, UHF) and increases further for 99.5% coverage, as expected given 3GPP’s higher operating frequencies.  For simplicity of comparison Table 3 assumes mobile terrestrial infrastructure.  Here the ‘Heavy foliated 50km2’ range is not suited to solely terrestrial 3GPP deployment and selected aerial (e.g. UAV, blimp) base stations provide an alternate flexible paradigm.   

3GPP frequencies and higher coverage requirements for multimedia data streams likely require increased infrastructure over traditional narrow-band Networks.  In the following section a 3GPP life cycle cost model is presented considering increased infrastructure cost plus 3GPP User Equipment technology sustainment cost reductions.

DISCUSSION

Previous doctrine and historical lessons drove requirements for direct fire training capability whereas the contemporary environment has changed dramatically favouring command of electromagnetic spectrum ‎[8]‎[9], precision fires and tempo derived from real time-shared situational awareness ‎[10].   Today realistic collective training with replication of these contemporary effects is largely now constrained by the limitations of legacy communications networks.  

Table 3 earlier demonstrates additional base station infrastructure required to support laser engagement training (i.e., 95% coverage) and future laser-less & CGF effects (i.e., 99.5%).  Life cycle cost acquisition compares legacy communications, typically with two or three (training data; instructor voice; instructor data/video) overlapping communications networks plus through life costs savings associated with reduced battery management support.  In this case battery savings capitalise on extensive 3GPP User Equipment development for commercial markets.  

The incremental life cycle cost model of Table 4 illustrates infrastructure cost offset by battery management (typical of a European or US range) over a ten-year life of type as a private network.   Significantly, at lower 3GPP frequency increased infrastructure payback can be within first year given battery and in-field contact team savings.   Higher frequencies and coverage accrue those same savings but to lesser financial outcome.   Note that life cycle cost itself does not account for increased training outcomes; i.e., most readers carry a Smartphone based on increased effectiveness, and that paradigm also applies here of increased cost/benefit. 

Joint and multi-national training is a cardinal requirement.   Live entity Network interoperability however has been constrained through national / regional spectrum allocations for legacy networks.  Here 3GPP allows multi-national interoperability through global roaming bands and or the use of non-traditional spectrum.

Capability like the ubiquitous Smartphone is (likely) realised in the Defence domain, an example being US Army’s Android Team Awareness Kit (ATAK).   3GPP allows device flexibility including Bring Your Own Device (BYOD) for Division size surge and/or Training as a Service events.   As earlier, cyber resilience is a baseline requirement noting the very real vulnerability of public Networks and/or fielding uncontrolled / BYOD User Equipment.

3GPP has generational advantages in on-going evolution and validation driven by commercial forces.  Strong standards basis, vendor community and global installed base ensure backward compatibility which is important in terms of Defence’s ten+ year life of type expectation.   While addressed separately, 3GPP communications may either embed with operational instrumentation or alternatively be supplied as a service and in this later case allowing industry flexibility in adopting selected 3GPP advances. Those selected advances would note the lesser utility of 5G (mmWave) in collective training’s predominantly rural environments, but equally self-interference cancellation ‎[7] (which realistically only a mass market can fund) significantly increases spectrum availability and hence longer-term training data streams. 

3GPP is fielded in collective training, albeit in cases only as a replication of legacy narrow-band data streams. Experience from those sites include:
•    Public / private Network design decision requires life cycle cost assessment, in-turn driven by the communicated data streams;
•    Increased employment of (User Equipment, Network) cyber protection measures;
•    Adoption of a ‘participative platform’ model, ensuring effective technology insertion of new and third-party simulation subsystems;

3GPP is a generational upgrade decision, from which new capability and through life technology insertion is hosted.   Legacy narrow-band networks are constraining training capability growth.  Live Training is at a point of inflexion during this 2020 decade, predicated on enhanced LVC / CGF, weapon effect & visualisation training capabilities and readiness outcomes for which emergent technology is currently fielding on high capacity low latency Networks.

CONCLUSION

Paradigm changes in collective training will deliver generational improvement in force readiness outcomes during this decade.   In addition to Live weapon effect simulation improvements, the ability to integrate, sense & see engageable CGF will enable enhanced (entity, effect, environment, etc.) realism and training complexity. Delivery of this emergent capacity is dependent on the exploitation of pervasive wireless, low latency communications (Network) coverage across home station and larger collective training areas.  Future training capability will be enabled or precluded dependent on the Network. 

In-service fleet constraints led to current collective training sites employing multiple separate networks (training, voice, data) to meet the training need.  Live training’s paradigm shift, increased data streams and technology advancement now allow these Networks to transition to a globally endorsed standards-based communications architecture, enabling growth in capability and joint & multi-national interoperability. 

3GPP (i.e. 4G, LTE, 5G) global communications standards highlighted in this paper currently are successfully exploited in selected collective training sites.  These progressive sites are capable of hosting Live training’s multimedia data streams and seamlessly scaling from Platoon through to Brigade data capacity & entity counts.  3GPP exploitation requires key design decisions on the following:
•    Securing spectrum, either as private (traditional or non-traditional bands) or public (i.e. Network Operator) access;
•    Infrastructure deployment, ensuring necessary Network capacity and enhanced communications coverage for system migration and through life training technology insertion;
•    Cyber resilience, which while not a primary topic of this paper, notes migration from ‘bespoke’ to ‘public’ Network and User Equipment alternatives in the face of a persistent threat.
Deployment of that 3GPP training Network is a foundational Live training sub-system from which next generation training and platform capability will be hosted.  

REFERENCES    

[1]    SISO-GUIDE-003-00-2016, Guide for UCATT Live Simulation Standards and Architecture, Version 1.0, 9 May 2016; from https://www.sisostds.org/ 
[2]    ‘The contribution of ISTAR to operations’, UK House of Commons, Defence Committee, Eighth Report of Session 2009–10, 16 March 2010.
[3]    Watling, J., ‘The Future of Fires, Maximising the UK’s Tactical and Operational Firepower’, Royal United Services Institute for Defence and Security Studies, November 2019.
[4]    Jacobs, M.W., ‘Improving Spectrum Access for Military LTE Systems’, Armed Forces Communications and Electronics Association (AFCEA) Army Signal Conference, March 2018.
[5]    van Sambeek, M., ‘5G Technologies in Military Communications’, C2COE Symposium “Get Connected” 2019 Brussels, June 26 – 27, 2019.
[6]     ‘NATO and phone hacking; Enemy armies with black mirrors’, The Economist, 22 May 2021, p42.
[7]    J. Brand, ‘The Radio That Can Hear Over Itself: Self-interference cancellation allows radios to transmit and receive on the same frequency’, IEEE Spectrum, vol. 58, no. 3, pp. 30-35, March 2021; from doi: 10.1109/MSPEC.2021.9370027. 
[8]    ‘Electromagnetic Spectrum Superiority Strategy’, U.S. Department of Defense, October 2020.
[9]    Clay, M., ‘To Rule the Invisible Battlefield: The Electromagnetic Spectrum and Chinese Military Power’, War on the Rocks, 22 January 2021.
[10]    Nofi, A.A., ‘Defining and Measuring Shared Situational Awareness’, Center for Naval Analysis, CRM D0002895.A1/Final, November 2000.