While the drive towards 5G systems is irresistible, foreign commercial developers leading the charge present unavoidable security concerns.
Military communications at the tactical edge always struggle to obtain the bandwidth they need, particularly for the most demanding applications such as real time transmission of high definition video. The current generation of serving soldiers, and even more so the upcoming generation from whom militaries seek to recruit, have grown up with mobile phones, smartphone and tablets with constant high bandwidth connectivity. They are digital natives who can make the most of these technologies and often find creative ways of using them unanticipated by their inventors and developers, so armed forces want to make their tactical communication systems feel, work and behave as much like the smart devices their soldiers are used to using.
These have been key drivers behind military adoption of 3G and 4G/4G Long Term Evolution (LTE) cellular communications technologies and their keenly anticipated take up of emerging 5G (fifth generation) systems, the first commercial applications of which are due to roll out this year, which as well as greater capacity also promises greater speed and security.
Higher radio frequencies offer greater bandwidth and carrying capacity fundamentally because more radio waves (peak-to-peak cycles), which can be modulated to carry the desired signal, pass a notional fixed point in a given time. For example, 4GLTE networks use seven frequency bands between 700MHz (700 million cycles per second) and 2.6GHz (2.6 billion cycles per second) with wavelengths in the microwave bands. Using bands of frequencies between 1GHz and 6GHz, 5G overlaps with 4G LTE at the lower end, with most services expected to be around 3.5GHz. This is well into the millimetre wavebands and promising much greater bandwidth and consummately higher data rates, and channel widths up to 100MHz. However, some services will even use spectrum from bands above 24GHz with channel widths between 50MHz and 400MHz, according to the International Telecommunications Union (ITU). Potentially, 5G can use frequencies up to 300GHz.
Wavelength trade-offs
While higher frequencies can carry much more information, the shorter wavelengths suffer more from attenuation in the atmosphere and the effects of airborne obscurants including rain, so effective communication ranges tend to be shorter. This implies an inevitable trade-off between bandwidth and range, as some signals won’t propagate more than a few hundred metres, while some wavelengths have difficulty passing through walls, which is bound to cause problems in urban environments.
Shorter signal ranges can be overcome by a variety of techniques including simply providing more relays, which can be dedicated devices or functions built into others, perhaps every cooperating radio in a given operational area, so that they can relay friendly third party signals without interrupting services to the primary user, for example.
One of the keys to this kind of capability is 5G’s support for ‘massive MIMO’, which is a significant extension of the Multiple Input, Multiple Output concept used by existing LTE and wifi systems to increase signal carrying capacity without occupying more bandwidth.
Massive MIMO
MIMO systems can carry more than one digital data signal over the same radio channel at the same time. One method is to exploit polarity. If the channel can handle a vertically polarised and a horizontally polarised radio signal at the same time they can carry different information, effectively doubling the channel’s data capacity. Massive MIMO systems make use of multiple antennas, with eight receive and eight transmit antennas usually considered the threshold for a system to be defined as massively MIMO. With different polarities and multiple antennas to manage, massive MIMO communication systems need advanced signal processing capabilities and therefore complex software and a lot of computing muscle in every network node, but the computer industry is more than capable of providing that.
What is likely to be more of a challenge is making decisions about how much to rely on civilian 5G infrastructure, in which Chinese telecoms giant Huawei has both a big lead in global deployment and a major price advantage over western competitors (the two are not unconnected), and how much to invest in dedicated military equipment that operate independently of potentially compromised infrastructure overseas and provide connectivity where there is no other infrastructure.
Chinese puzzles
Naturally, the fear is that that Chinese equipment will have back doors in it that will allow the Chinese government access to sensitive information, either directly or through pressure on Huawei. This suspicion was given more credence by the latest annual report published in March to the UK National Security Adviser by the Huawei Cyber Security Evaluation Centre (HCSEC) Oversight Board.
HCSC is a facility in Banbury, Oxfordshire, belonging to the Chinese company’s UK division established eight years ago under a set of arrangements between Huawei and the UK Government to mitigate any perceived risks arising from Huawei’s involvement in critical national infrastructure. Established in 2014, the Oversight Board is is chaired by Ciaran Martin, who is the chief executive officer of the National Cyber Security Centre (NCSC), and is an executive member of GCHQ’s Board with responsibility for cyber security. The Oversight Board includes a senior executive from Huawei as deputy chair, senior representatives from the British Government and telecommunications sector.
Limited assurance
Despite acknowledging capability improvements the report found a number of ongoing problems. These include significant technical issues in Huawei’s engineering processes, leading to new risks to UK telecommunications networks, and that no progress had been made on the remediation of issues identified in the previous report. Furthermore, the report found, the Oversight Board can provide only limited assurance that the long-term security risks regarding currently deployed equipment can be managed, that it will be difficult to risk-manage future products appropriately.
James Andrew Lewis, senior vice president and director, Technology Policy Program at the Centre for Strategic and International Studies CSIS), a US think tank, wrote that the US and, by implication, other western countries can manage 5G risks by ensuring that their companies can continue produce advanced technologies and that they face “fair competition” overseas and by working with “like minded” nations to develop a common approach to 5G security.
He noted that western companies routinely outspend their Chinese competitors in 5G research and development, that they hold 10 times as many 5G related patents and that Chinese companies depend on western companies for the most advanced 5G components, but accused the Chinese government of effectively subsidising its industry with easy access to state finance. He also recommended that the US invest in, research and adopt a comprehensive approach to combating non-tariff barriers to trade.
It’s clear from this that the military’s adoption of a still evolving communications system over which it has no direct control and key elements of which are produced by potential adversary countries is something that has to be handled with extreme care, involving high politics and trade policy as much as technology.
Published in Tactical Radios 2019/2020 supplement.
