Antenna design and measurement are at the heart of the race to 5G
In a world where mobile devices have outnumbered people, it is easy to forget we lived without smartphones 15 years ago. From 1G to 4G, each new generation of mobile networks has brought higher speeds and new uses, which have had huge impacts on our personal and professional lives. Today, the industry is buzzing about the arrival of “5G,” which is expected between 2017 and 2020. With speeds up to 10 gigabits per second and ultra-low latency around one millisecond (50-times faster than 4G), this next-generation network holds enormous promise, including smart cities, driverless cars, critical health care and the “internet of things” revolution, to name just a few. It is no surprise that, similarly to the Olympic Games, a technological worldwide race is on to be the first and to set the standard. The challenges ahead are manifold, and mostly revolve around the harmonization of the radio spectrum, antenna design and measurement.
A brief overview of the challenges ahead
A drastic harmonization of the radio spectrum will be instigated by 5G. Firstly, remember that data is transmitted via radio waves, which are split into bands of different frequencies, with each band reserved for a different type of communication: aeronautical and maritime navigation signals; television broadcasting; mobile data; military use; etc. As new protocols are developed, radio frequencies are limited to what’s left over. Finding new space and coordinating the use of that space will demand complex negotiations.
Secondly, new applications such as driverless transportation or remote surgery mean that a sudden data connection drop is not an option. An uninterrupted user experience will have to be provided by 5G every time as if capacity were limitless. Several networks are currently providing connectivity for end-user wireless devices: cellular, Wi-Fi, millimeter wave and machine-to-machine are a few examples. It is believed that 5G is likely to integrate the coordination of the various protocols and dispersed frequency bands so as to offer the end-user the expected seamless connection.
Many technologies are being evaluated. And, similar to the coordination of protocols, 5G networks will not be based on one single technology but on a combination of several. These technologies will have to work alongside each other – if not together – in an optimum way to support a wide range of upcoming exciting applications.
Millimeter wave technologies and massive multiple-input/multiple-output antenna technologies are two such advances. Millimeter waves allow for high-speed and high-capacity data transmission, yet they can only be used for short-range, point-to-point, line-of-sight connections.
Massive MIMO could be a valid alternative. The term refers to a technique in which the base station employs a high number of antennas that create localized beams toward each device, allowing significant gains in capacity and traffic density. The basic physics principles for massive MIMO are already proven and experimental systems are being deployed.
The measurement industry is being put to the test
The necessary mix of technologies required for 5G to hit the airwaves means the antenna measurement industry is being put to the test. Innovation in this industry will have to rapidly follow suit with flexible solutions to measure the variety of new devices that will need evaluation. On top of testing each new technology, it will also have to test the many various combinations of technologies, network elements and protocols to ensure correct interoperability.
Among the many to take shape, both millimeter wave and massive MIMO technologies bring challenges. For those aiming to benefit from the high-speed, high-capacity of the millimeter wave spectrum, the players will require systems capable of providing measurements in the millimeter wave bands. As most available wider bandwidths of the radio frequency spectrum are in the higher frequency bands – as high as 100 gigahertz – a key part of the challenge resides in designing the right antennas as well. Once they have the two that coincide, they’ll gain considerable traction in the race.
The MIMO system works by having the baseband algorithm respond to the RF channel characteristics. As the baseband is split between the transmitter and the receiver, and as these two elements are likely to come from different suppliers – the infrastructure vendor and the device vendor – then the full detailed list of the parameters required for the algorithm must be specified in the technology standards documents. For massive MIMO, this is likely to be a very complex and detailed specification to ensure full interoperability.
Another challenge related to this area is the issue of “connectorless devices,” as large antenna arrays required for massive MIMO will be designed to be compact, and therefore cost and deployment efficient. This means there is unlikely to be space for RF connectors or test ports to attach test equipment. The miniature size of millimeter wave antennas has already led to this dilemma. The expected logical next step is therefore “over-the-air” testing.
Generally speaking, the future of RF device testing is challenging and will ask for very precise instrumentation and flexible testing solutions in order to deal with millimeter wave transceivers and/or better intelligence for massive MIMO. More complex, shielded chambers will be required, even tunable to a variety of frequency bands. Alongside this, the simulation of multipath signals using fading simulators will continue to grow in importance, as well as the technical demands and capabilities required in such equipment.
Lastly, did we mention the pressure of time? This complex testing needs to take place in the minimum amount of time because the race is on.
The Olympic Games of 5G development
World sporting events are a key driver for technology deployment and trials on a grand scale. In 2018, the Winter Olympics in South Korea and the World Cup in Moscow both offer the perfect opportunity to launch 5G trials in real-life scenarios.
In 2020, the Japan Summer Olympics look set to become a starting point for a live demonstration of 5G, which could be the base of a commercial deployment.
At this stage, it’s not possible to know which country or which company – or consortium of companies – will win the 5G race, but what is sure is that the win will depend on not only the speed of innovation but also the speed at which testing capabilities for those devices will follow. This is a complex challenge that the industry excitedly faces, and I believe the first one to pass the tests with flying colors will hit the market running and set the standard for the rest to follow.
Nicolas Gross is currently the director of applications for MVG Industries, Paris. After receiving his engineering degree from Ecole Nationale Supérieure de Techniques Avancées Bretagne in 2005, he joined the company SATIMO (part of the MVG group) where he worked for several years as an antenna engineer. In 2007, he was made head of multiprobe antenna measurement systems development. In August 2009, he became director of the applications department, leading software, systems and product developments in the field of antenna measurement. In addition to his industrial responsibilities, he has participated in several studies and has to his credit several publications and patents in these fields.
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