Viewpoint
Everyone in the telecommunications industry today believes and understands that we are in an unprecedented period of change and transformation. It’s not just about booming internet growth and huge bandwidth demand fuelled by an insatiable need for video, it’s about how people right across the planet are looking to communicate with each other.
Social media has already changed the way we live our lives, even if we perhaps don’t always realise it. The Internet of Things (IoT) is set to take things to a whole new level and behind all this is the network – the unsung “hero” trying to deliver increasing bandwidth and capability on a daily basis.
The saviour of the network, especially as the majority of this growth will require mobility, is thought to be 5G technology. While most people don’t anticipate 5G deployment much before 2020, growth is predicted to be exponential – with Juniper Research predicting revenues booming to 65 billion US dollars by 2025.
But 5G will not just appear overnight and ZTE has been working from its base in China and increasingly in Europe to make sure that networks smoothly evolve towards 5G. It is already working with leading European operator brands such as Hutchison and Deutsche Telekom and expects to name further Tier 1 operators in Europe very soon.
ZTE’s approach has been to deliver what it terms its Pre5G solution – which is exactly what it says – a solution prior to 5G itself which works with 4G elements in the network to deliver a 5G-like experience. It has already signed a Pre5G memorandum of understanding (MOU) with Hutchison Drei in Austria, which will see the very first Pre5G trial site set up anywhere in Europe.
This is just the latest development towards 5G by ZTE; now recognised across Europe as one of the pioneers behind what would follow 4G. It first proposed a cloud radio solution based on 4G access networks and mainstream mobile bearer as early as 2012. This solution suppresses interference on LTE networks and significantly improves network performance. It also gives consistent access beyond that of 4G users on LTE networks. Cloud radio has been commercially used by China Mobile, China Telecom and Hong Kong CSL and in all cases access experience was improved for users, particularly at the cell edge.
Austria to lead Pre5G in Europe
At the same time ZTE developed the Pre5G solution now about to be tested in Austria. This solution is backwards compatible with commercial LTE UEs. By utilising an operator’s existing sites and spectrum resources, Pre5G will greatly improve network capacity – a critical requirement for the future.
From a technical perspective, pre5G encompasses massive MIMO, virtual cells, Multi-User Shared Access (MUSA) and software-defined air interfaces.
As a potential 5G core technology, massive MIMO can use 100 or more antennas, which is an order of magnitude higher than that used by traditional base stations. Consequently, massive MIMO transmits more independent data streams between systems and UEs to ease spectrum efficiency. Simulated results show that the throughput of a massive MIMO base station can be six to eight times that of a traditional two-antenna base station. Massive MIMO enables an operator to meet growing demands for data with existing sites and spectrum. Even if commercially used 4G UEs could not support multi-antenna technology, massive MIMO base stations can increase the overall capacity of systems through multi-user MIMO.
Also, by achieving accurate 3D beamforming and user tracking, massive MIMO significantly improves network coverage and reduces interferences from neighbouring base stations.
Massive MIMO can be used in complicated wireless environments such as city centres or suburbs. Virtual cells turn traditional cell-centric mobile access networks into user-centric access networks. Each user that accesses the network has an associated virtual cell comprising several neighbouring physical cells of the user. These physical cells co-ordinate with each other to serve he user. When the user moves within the network, the physical cells contained in the virtual cell change, but the virtual cell ID remains the same. Because there is no handover when the user moves, the user always had good coverage and the best access services from multiple neighbouring physical cells.
Virtual cells are a revolution in mobile access because instead of users finding networks – the networks chase users.
Overload capacity on networks increased by up to 300%
Avoiding interference between users in this environment is vital and to achieve this 3G Code division multiple access (CDMA) uses code domain orthogonality and 4G OFDM uses sub-carrier orthogonality. However, the system access capacity is constrained by the orthogonality. By leveraging users’ transmit power differences ZTE’s MUSA applies non-orthogonal complex spreading sequences at the transmitter for data modulation, as well as successive interference cancellation algorithms at the at the receiving end in order to filter out interferences and restore user data. It also allows users to reuse the same degree of freedom (DOF) of an air interface to improve system resource multiplexing. In addition, there is no need to guarantee orthogonality between users or guarantee the scheduling mechanism of air interfaces. This is ideal for high-density, high-capacity mobile access scenarios which will be critical in the 5G world.
Theoretical simulations already carried out by ZTE show that the MUSA algorithms can increase the overload capacity of wireless access networks by more than 300% – meaning that the anticipated demands of the Internet of Things (IoT) can be met.
In the 5G era, diverse services will have different requirements in terms of access network performance. From smart terminal users, equal importance is given to both access rate and mobility. For IoT applications, massive access capacity, efficient low-rate forwarding and lower power consumption are core demands. For the rapidly developing vehicle to vehicle market, especially autopilot applications, low latency is very important.
The danger is that is dedicated access systems are deployed for different types of applications, 5G networks will become too complicated and the operational and maintenance (O&M) costs will be too high. There ZTE proposed software-defined air interfaces (SDA) that use a high performance mobile access network infrastructure to satisfy all the needs of a variety of services. This simplifies 5G access network architecture and saves significantly on network construction and O&M costs.
ZTE’s massive MIMO base stations have been deployed in trials in China as long ago as 2014 – with China Mobile. The highly successful results were initiated, monitored and confirmed by the China Mobile Research Institute (CMRI) and it is this R&D strength, coupled with real experience, that ZTE is now bringing to Europe.
Deutsche Telekom also partners with ZTE
As well as the agreement with Hutchison in Austria, where ZTE has already been a strategic partner for Drei’s RAN and core network modernisation, leading to a full nationwide 2G, 3G and 4G footprint, ZTE is a partner in the Deutsche Telekom 5G Innovation Lab. This facility is looking to develop the necessary architecture for 5G and to foster innovation and steer vital standardisation work.
In standards development, ZTE is working alongside China’s IMT-2020 Promotion Group, the IEEE 5G technology research group and last year also joined Horizon 2020, a European Union funded programme – a massive 80 billion Euro project looking to take ideas and indicatives from the laboratory to the market.
ZTE’s work in 5G is slowly being recognised in Europe and earlier this year this was acknowledged when the company won prestigious GSMA awards with Pre5G Massive MIMO – Best Mobile Technology Breakthrough and The CTO’s Choice for 2016.
Europe is driving hard to realise 5G and to make sure it has the network infrastructure to give the region a true world-class solution. Contributing hard towards that delivery behind the scenes is ZTE – with both its partner organisations within Europe and through its massive R&D labs and unique trials experience from the giant and highly demanding Chinese market.
About Dr FANG Min
Dr. FANG Min is director of 5G Research and Collaboration in the Wireless Division of ZTE Corporation. She has long experience of wireless communications research, innovation, standardization and development over 20 years. Currently, she is coordinating the internal and external resources on the 5G research and innovation activities. Her R&I interest include new services, new architecture, new air interface, virtualization and other enabling technologies for future wireless communications.
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