Partner interview: Ahead of the GSMA’s Mobile 360 Europe event, Mobile World Live spoke with Alex Ai, director of the Wireless Network Solution Department, European Region, at Huawei, about 4.5G and its potential to enable new services for operators.

Alex Ai: Given the current explosive development of mobile broadband (MBB), we expect the number of MBB users around the world to reach 6.7 billion by 2020, while each user is expected to use as much as 5GB of data per month. Meanwhile, there is already a need for wide scale development of an Internet of Things (IoT). By 2020, there will be some 31 billion IoT connections worldwide. These days, mobile network operators are placing more and more importance on the exploration of vertical markets and IoT is a typical example of this trend.

Huawei proposed the 4.5G concept based on a deep understanding of the mobile broadband industry. 4.5G has two targets: first is to provide gigabit transmission capability for MBB; second is to explore new vertical markets for operators.

4.5G will need to be able to support 2K/4K video, virtual reality (VR), augmented reality (AR), drones and IoT services, which may emerge in the next two to three years. 4.5G is based on 4G evolution, so what is required to transition from 4G to 4.5G is only software upgrades or minor hardware changes. Current investments in 4G infrastructure are well protected.

4.5G is the ineluctable way to 5G. 4.5G will coexist with 5G, which will adopt a new air interface, for a long time.

Another important role for 4.5G is to prepare for the arrival of 5G. It allows us to adopt certain 5G candidate technologies in 4.5G networks, benefiting operators before 5G arrives. It also gives the opportunity to adjust network architectures ahead of time for the introduction of 5G.

What are the defining characteristics of 4.5G technology?
Huawei 4.5GAA: After more than a year of development, 4.5G has already made great progress.

The three guiding principles for 4.5G proposed by Huawei have become the new network benchmark in the MBB industry:

  • Gb/s: A peak rate of over 1Gb/s
  • Experience 4.0: A mean opinion score (MOS) over 4.0 for voice and vMOS over 4.0 for video services, showcasing the high definition (HD) user experience
  • Connection+: Empowering vertical markets, including NB-IoT for cellular narrowband internet of things and LiTRA for public safety networks based on LTE integrated broadband trunked radio.

With regard to 4.5G standardisation, in October 2015 3GPP approved LTE Advanced Pro as a distinctive marker that evolves the LTE and LTE-Advanced technology series. In terms of deployment, over a dozen of the world’s leading operators began deploying 4.5G on pre-commercial or trial networks. We can expect that more than 60 4.5G networks will be commercially deployed around the world in 2016.

Another important role for 4.5G is to prepare for the arrival of 5G. It allows us to adopt certain 5G candidate technologies in 4.5G networks, benefiting operators before 5G arrives. It also gives the opportunity to adjust network architectures ahead of time for the introduction of 5G. Finally, 4.5G can help investigate and cultivate new services and market sectors for 5G.

The following are key technologies of 4.5G:

  • Massive MIMO (FDD)
    4T4R RF modules working in medium and high frequency bands will be widespread by 2016. With four TX channels, these RF modules support 4×2 MIMO and 4×4 MIMO. Terminals with two or four RX channels can be used. Massive MIMO fully uses spatial multiplexing and diversity technologies, significantly increases spectral efficiency, and improves cell edge user (CEU) experience. Huawei’s innovative enhanced MIMO (eMIMO) can maximise the benefits offered to terminals with two RX channels when RF modules have four TX channels. eMIMO can support Blade RRU with traditional antennas, Blade RRU with split antennas, or AAU (Active Antenna Unit) with 4T4R capability. With enhanced features in Release 12 and beaming forming coordination between cells, eMIMO will provide more gains to UE with two RX channels. Moreover, eMIMO will be further enhanced in 3GPP Releases 14 in order to maximise the value of 4T4R RF deployment.
  • Massive CA
    4CC and 5CC CA will be deployed for commercial use in 2016. By aggregating four or five carriers (including FDD and TDD), CA not only increases the peak rate for users but also increases the cell edge and average cell throughput. Huawei’s innovative enhanced CA (eCA) implements inter-eNodeB carrier aggregation based on relaxed backhaul to greatly increase the proportion of SCell activations. In addition, eCA allows flexible aggregation of optimal PCells and SCells for CA UEs to significantly increase perceived data rates. CA will further optimise PCell and SCell selection, simplify implementation, and decrease inter-cell interference.
  • High-order modulation
    256QAM is expected to be deployed commercially in 2016. It increases the peak rate by 33 per cent compared with 64QAM. While 256QAM can be used for both indoor micro cells and outdoor macro cells, the main target is to maximise the capacity for outdoor macro cells.

What is the state of progress with regard to operators rolling out 4.5G?
AA: Global mainstream operators have unveiled large scale deployment of 4.5G networks, which is dependent not only on terminal maturity, but also on the early verification of key technologies and on the readiness of the whole industry.

Norway, Germany, Italy, Belgium, France, Kuwait, Saudi Arabia, UAE, China, Hong Kong, Japan, Canada, Singapore and other countries have demonstrated a transmission rate of over 1Gb/s on commercial networks.

UK and South Korea have started constructing their national LiTRA-based public-safety networks using broadband trunked radio.

“It is estimated that, in 2016, there will be more than 60 4.5G networks around the globe”

Countries including Spain, Korea, China, UAE and Germany have started pre-commercial deployment of NB-IoT. It is estimated that, in 2016, there will be more than 60 4.5G networks around the globe.

By April 2016, there were 20 commercial or trial 4.5G networks.

What is needed to enable 4.5G to become more widely adopted?
AA: Huawei has launched eRAN11.1 software and GigaRadio platform for 4.5G deployment. At the same time, the ecosystem needs to be mature for 4.5G. LG and Samsung have launched 600Mb/s smartphones and Qualcomm announced its X16 modem at Mobile World Congress 2016.

When do you think we will see operators deploying narrowband IoT connectivity (NB-IoT)?
AA: The NB-IoT standard will be finalised in June 2016. Commercial deployment is expected in the second half of 2016.

What are the advantages that NB-IoT offers over other low power, wide area alternatives?
AA: NB-IOT is a 3GPP standardised LPWA technology; it could reuse the most legacy network elements to achieve fast deployment, and works on licensed spectrum which is already owned by operators. It can accompany UMTS or LTE networks. Licensed spectrum adoption guarantees network performance with less interference than other LPWA alternatives.

How does 4.5G help operators move toward 5G technology and services
AA: Getting prepared for 5G is one of the most important goals of 4.5G. It involves two aspects:

  • Introduction of certain candidate 5G technologies on 4.5G networks phase by phase based on their technological maturity. These technologies can be implemented by software, with no need for major hardware changes. They have little impact on terminals.
  • Network architecture adjustment in 4.5G. There are two reasons why the network architecture will need to be modified.
    First, 4.5G and 5G networks will have to coexist for quite some time. The network architecture must be designed with long term coexistence of 4.5G networks with the new air interface of 5G networks kept in mind. Second, 5G networks will need a network architecture that meets backhaul requirements for lower end-to-end latency and ultra-high bandwidth; accommodates network slicing; and meets openness requirements for programmability and adaptation to different service types.

What is LiTRA, and how does it fit into the 4.5G landscape?
AA: Another solution that empowers vertical markets, LiTRA, is well suited to public safety, including fire services, ambulances, and the police.

Trunked radio systems came into being in the late 1960s and early 1970s. Unlike common point-to-point full-duplex mobile communications, trunked radio, also known as push to talk (PTT), works half-duplex, point-to-multipoint. PTT has low latency and large capacity. It is good for group communications and allows for instant responses and onsite real-time dispatching. It is widely used in the public safety, public utility and enterprise fields.

Trunked radio systems are currently evolving from narrowband to broadband and from private networks to public networks. Traditional trunked radio technologies were developed for narrowband private-network communications. Narrowband technologies are voice-centric. They do not support high-speed data services, such as video and multimedia. In addition, the private-network architecture creates a variety of issues, including closed industry chains, high equipment and network construction costs, expensive terminals, and high maintenance costs. These technologies do not meet customers’ business needs.

PTT over LTE, represented by LiTRA, addresses these issues. With the high bandwidth and low latency of LTE networks, LiTRA not only rivals traditional trunked radio systems in performance, but also provides professional multimedia trunking services, which includes video calls, video surveillance, file transfer, and GIS services. More important, however, is that LiTRA is deployed using operators’ existing LTE networks. This significantly reduces network construction and maintenance costs, provides better network coverage and roaming services, and is compatible with smart LTE terminals. In this sense, LiTRA breaks out of the closed industry chain and can provide more professional, more efficient trunking services.

“Huawei believes there will be special challenges if commercial LTE networks are directly used for public safety services”

LiTRA is a Huawei-developed professional trunked radio solution that complies with 3GPP specifications and is based on public LTE networks. This solution aims at helping operators build secure, efficient, and professional LTE networks to provide public-safety services.

Huawei believes there will be special challenges if commercial LTE networks are directly used for public safety services. To enhance LTE network abilities to address public safety emergencies, LiTRA has made improvements to five different aspects of LTE networks, including QoS, MCPTT, and congestion control. Moreover, LiTRA has end-to-end products and solutions to help operators rapidly deploy trunking services and seize market opportunities. These products and solutions include the application platform, dispatch consoles, apps, and anti-shock, waterproof and dustproof terminals.

How can 4.5G enable operators to meet growing demand for high-quality video services?
AA: In the next few years, the visual experience will undergo a transition from HD video (currently popular for mobile video 720p) to 4K, ultra-HD and even virtual reality. People’s demand for better video experience will be endless and UHD and virtual reality are steps forward in delivering such immersive experiences. From a mobile network perspective, 4.5G presents the platform for ensuring such an experience. 4.5G is the natural evolution of 4G. It offers enhancements on LTE-Advanced to meet new services and the trends emerging in the next years.

Before answering “How?” let’s see what we have today. Currently video is the dominating data service which is the guarantee of revenue growth for the mobile operators. The expected CAGR of video traffic for the coming three years is 66 per cent. At the same time, subscribers have a higher requirement of mobile video experiences – one third of subscribers expressed a strong view that video buffering is simply unacceptable. 50 per cent of users blame mobile operators for video delivery lagging behind the latest handset technology, which is driving the industry forward.

Then let’s see what are the targets defined for 4.5G. The higher throughput (1Gb/s) will bring also higher average speed for playing/streaming video, thus ensuring the support of higher video resolutions. Lower latency is another aspect of 4.5G. Reducing the E2E RTT to 10ms will bring optimisation of approximately five times compared to LTE and will allow smooth video play with faster loading and no stalling. The higher number of connections (100k/sq.km) means that more users will be able to enjoy the high-quality video service simultaneously. And finally, the mobile network quality will be improved, so that it can guarantee best user video experience (U-vMOS level 4.0).