5G standards updated ahead of industry freeze

While many 5G standards on speeds, technologies, latency, and efficiency are set to be frozen by the end of the year, spectrum and radio specifications are still being debated.

The International Telecommunication Union (ITU) and 3GPP have updated their 5G characteristics and requirements standards, with speeds, spectrum, and latency all due to be decided later this year.

Speaking at the 5G Innovation Summit at the Huawei Digital Transformation Forum in Barcelona on Sunday, ITU Radiocommunication Bureau director Francois Rancy said the key characteristics and requirements of 5G will be subject to final formal approval in November 2017 when study group 5 meets.

Under the current International Mobile Telecommunications (IMT) 2020 technical performance requirements, 5G networks must be capable of downlink peak data rates of 20Gbps; uplink peak data rates of 10Gbps; downlink user-experienced data rates of 100Mbps; uplink user-experienced data rates of 50Mbps; 4ms latency for enhanced mobile broadband; and 1ms latency for ultra-reliable low-latency communications devices.

5G networks must also enable mobility maximum speeds of between 0km/h and 10km/h for pedestrians, 10km/h to 20km/h for vehicles, and 120km/h to 500km/h for high-speed vehicles; a connection density of 1 million devices per square kilometre; downlink peak spectrum efficiency of 30 bits/Hz; uplink peak spectrum efficiency of 15 bits/Hz; and area traffic capacity of 10Mbps per square metre.

Other parameters being decided include energy efficiency, reliability, control plane latency, and mobility interruption time, Rancy said.

Frank Mademann, chair of SA2 for 3GPP -- the technical specification group working on 5G network architecture service system aspects -- also provided an update on the characteristics and features of 5G, with much of it hinging on network slicing.

"The 5G system is defined as a set of self-contained network functions that allow for flexible as well as customised deployments, specifically via network slicing," Mademann explained at the 5G Innovation Summit.

According to SA2's most recent list of characteristics and features, 5G networks must be deployed in virtualised environments; have a service-based architecture to support modular design; have a common core network that supports various access networks; support IP and other data sessions and have a flexible QoS framework; and separate their authentication function from all other security functions.

They must also have access control and mobility management, policy, and charging control functionalities; contain options for IP session or service continuity in support of edge computing; support interworking and migration from 4G networks; support applications for IMS providing voice and emergency services; expose network capabilities and features for use by internal and external users; support access via untrusted non-3GPP access networks; and have a public warning system and short messaging service.

"One of the most interesting things is probably network slicing ... we can share or separate the resources now, providing multiple networks for the operators that are more or less separated from each other," Mademann said.

Burkhard Alfert, head of 5G Architecture at Deutsche Telekom, said that while it is encouraging to hear that 3GPP is looking into network slicing, more still needs to be done.

"I was very happy to be reminded again that SA2 is pretty much active on this arena, and network slicing has been in dedicated slides compared to all those other technologies," he said.

"On the other hand, I think network slicing is one of the areas we have to push further."

Deutsche Telekom earlier this month demonstrated Ericsson's federated network slicing system in partnership with South Korean telecommunications provider SK Telecom, making network slices from each telco available to the other across continents.

While Rancy said that the final spectrum band arrangements and detailed radio specifications are not due to be set until 2019-2020, the United Kingdom's Ofcom is in the midst of a push towards global harmonisation of the 26GHz frequency band.

"Spectrum is the lifeblood of the mobile industry," Philip Marnick, head of Spectrum for Ofcom, said at the Huawei 5G event.

"One of the key things we believe in is ensuring that spectrum bands are not just national, but actually spectrum bands can be global as much as possible."

As such, Ofcom is looking into three bands in Europe -- the 700MHz band, the 3.4-3.8GHz band, and the 26GHz band, the last of which it labelled as having the potential to be the global "pioneer 5G mmWave band".

According to Ofcom, the 26GHz frequency is also a prime band enabling spectrum sharing.

"In the UK, we're great fans of spectrum sharing. We need to live in a world where you share something in a way that co-exists," he said. "The 26GHz band is already shared by lots of services."

"We are supportive and are actively promoting this band as the priority millimetre wave band for global harmonisation, and we are contributing to the international work in the relevant ECC working group and with the ITU (for WRC-19), including taking a leading role in the studies on coexistence," Ofcom detailed in its 5G UK spectrum update [PDF] earlier this month.

"This band presents significant advantages compared to other millimetre wave bands. It already has a mobile allocation in the ITU Radio Regulations across most of the band; this makes it feasible for other countries to start using it for 5G.

"On the domestic side, we have initiated a program of work to develop proposals on how to make all or part of the 26GHz band available for early 5G deployment in the UK. We intend to publish a consultation on this in the first half of 2017."

Ahead of the standards freeze, NTT DoCoMo and China Mobile both outlined plans for their second-phase 5G trials during 2017.

Liu Guangyi, CTO of Wireless Development at China Mobile Research Institute, said the Chinese telco has already planned 5G field trials in Chengdu and Shanghai with Huawei, Beijing with Ericsson and Datang Mobile, Hangzhou with Nokia, and Guangzhou with ZTE.

Its second-phase 5G trials will make use of 100MHz of spectrum in the 3.4-3.6GHz frequency band and Massive Multiple-Input Multiple-Output (MIMO) using 128 antennas, with China Mobile also introducing 3D MIMO -- wherein 128 antenna elements will be deployed in both vertical and horizontal dimensions -- on its 4G networks from this year.

Similarly, NTT DoCoMo attained 18.27Gbps peak throughput speeds during its multi-user MIMO 5G trial in November in Yokohama Minato Mirai 21 District using 192 antenna elements over the 4.5GHz spectrum band, ahead of deploying two 5G trial sites before mid-year.

"From this year, we plan to conduct larger-scale and system-wide trials that we are calling 5G trial sites," said Takehiro Nakamura, VP and general director of NTT DoCoMo's 5G Lab.

"This year, we are using the proprietary specifications, but hopefully next year we can use the 3GPP-compliant specifications."

NTT DoCoMo's 5G trial sites will be offered in two Tokyo districts from May 2017 -- Skytree Town and Odaiba waterfront -- and will utilise the 28GHz and 4.5GHz frequencies.

Disclosure: Corinne Reichert travelled to Barcelona as a guest of Huawei