‘5G’ is succeeding in being overhyped before anyone even knows what it is, and before 4G has been widely deployed. Whether this points to shortening technology cycles or marketing desperation, most so-called 5G projects have been attempts by individual players to promote their favorite technologies as candidates for next generation standards. However, when Japanese carrier NTT Docomo talks next generation, there is usually more reason to listen, given the company’s track record in driving and shaping new technologies.
Docomo was so far ahead in 3G that ‘ ill-advisedly perhaps ‘ it launched its own pre-standard version, FOMA. It was also in the vanguard of R&D for 4G, feeding into LTE standards and testing gigabit systems way back in early 2011. It works closely with selected vendors to steer them in its preferred directions and tap into their combined R&D resources, an approach now matched by China Mobile. And it is doing the same for ‘5G’, working on experimental trials with six partners.
These partners include Docomo’s long term Japanese allies, NEC and Fujitsu, which are well versed in supporting the cellco’s R&D directions and, even in commercial scenarios, customizing equipment to ensure the operator can be early to market. The others are the major LTE OEMs ‘ Ericsson, Alcatel-Lucent, Nokia and Samsung ‘ but notably excluding Huawei and ZTE. That may reflect some of the same concerns about Chinese suppliers that the US has cited ‘ officially on the grounds of national security, but perhaps really because of commercial fear ‘ or a revival of the old competitiveness between Chinese and Japanese technology programs.
The basic aim of Docomo’s project is to get peak speeds to 10Gbps and above with very high availability and very low latency. The carrier wants the resulting systems to be commercially deployable in 2020.
The six partners will carry out experiments in parallel, with Docomo as the coordinating force. The particular focus is to test and confirm the potential for access networks running in high frequency spectrum, above 6GHz, but potentially up in millimeter wave ranges of 70GHz or 80GHz. This could theoretically support very dense, high capacity networks of very small cells.
In January, Docomo signed a memorandum of understanding with Nokia to explore the potential of the 70GHz band, with plans for an experimental 5G proof of concept system. This is being implemented using National Instrument’s (NI) baseband modules which currently make up the system for rapid prototyping of 5G air interfaces.
Ericsson said it would focus on the 15GHz band in its Docomo cooperation, as well as HetNet and antenna advances. And NEC’s particular activity will be to verify enhanced time-domain beamforming technologies, supporting very large numbers of antennas for small cells. This could improve Multiuser MIMO approaches to accelerating speeds, reducing interference and boosting capacity.
Another important focus will be to develop radio technologies which are optimized to new types of applications beyond conventional mobile broadband, particularly in M2M.
The first indoor trials will be held at Docomo’s R&D lab in Yokosuka, Kanagawa Prefecture this year, and it will move to outdoor field trials in 2015, in the same location. Its CTO, Seizo Onoe, said in a statement: “5G studies are starting to gain real momentum as we point toward 2020. I am delighted that we will collaborate on 5G experimental trials with multiple global vendors from this early stage.”
Late last year, Docomo achieved the world’s first transmission exceeding 1.2Gbps in a field test using a single-size antenna and a new technology called Smart Vertical MIMO for LTE-A. Docomo’s technology uses adaptive grouping of vertical antenna components according to the reception quality for mobile devices in the transmission area, enabling a single-size antenna to achieve throughput equivalent to that of a four-antenna system. Evolutions of such approaches will be fed into the 5G efforts too, as will work on high frequency bands, advanced MIMO and other key enablers, carried out in the individual 5G labs of Docomo partners such as Samsung.
However, the absence of Huawei means the cellco will not be tapping into that vendor’s extensive R&D program ‘ along with Samsung, the Chinese firm is supporting the UK’s 5G research center at the University of Surrey.
Despite all this effort, there is no real consensus in the industry, let alone the standards bodies, about what 5G will entail. There is dispute about whether it will need a fundamental change in the air interface, as 4G did, or whether the focus will be on other techniques which can boost data rates, network density and capacity, such as self-optimizing networks, software defined networking, new spectrum and new MIMO techniques.
However, some of these standards would not even be naturally governed by 3GPP, the body which controls mobile network standards. The IEEE in unlicensed spectrum networks, the IETF in web technologies, and other organizations might have a claim too, so the politics of standards organizations may well join the battles of vendors and operators to define the future.
Ulf Ewaldsson, Ericsson’s CTO, left the options suitably open and vague, saying in his statement: “5G will be a key component in the industry’s movement toward the Networked Society. I’m excited about the new technologies that we are exploring in the joint trial collaboration with NTT Docomo. This is an important step in the industry transformation we are experiencing.”