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LTE Evolution Lays the Foundation for Success in the 5G EraLTE Evolution Lays the Foundation for Success in the 5G Era

On the path to 5G commercialization, an increasing number of operators have recognized the importance of building a high-quality LTE network in the 5G era.

February 26, 2019

7 Min Read
LTE Evolution Lays the Foundation for Success in the 5G Era

LTE Evolution Lays the Foundation for Success in the 5G Era As commercial deployment of 5G networks begins, LTE, a foundation network in the 5G era, has ushered in another round of explosive growth. China Mobile obtained an FDD license in 2018 and will roll out FDD-LTE networks across China. In February 2019, China Unicom completed a tender for 416,000 LTE base stations to improve network coverage on the 900 MHz band and expand site capacity, laying a foundation for 5G deployment. British telecoms giant BT Group has been extensively deploying LTE networks before 5G commercialization and has planned to boost LTE geographic coverage from 90% in 2018 to 95% by 2020.

On the path to 5G commercialization, an increasing number of operators have recognized the importance of building a high-quality LTE network to business success in the 5G era.

1. LTE will replace 2G and 3G as the foundation network for voice, data, and IoT services, improving operation efficiency in the 5G era.

In the 5G era, we will witness the coexistence of 2G, 3G, 4G, and 5G. According to statistics, the proportion of operating expense (OPEX) to operator revenue increases by 10% for every new radio access technology (RAT) introduction. Coexistence of multiple RATs results in high OPEX. Moreover, 2G and 3G network revenue is declining. In some cases this means some operators cannot offset their OPEX on them. Migrating 2G and 3G services and spectrums to 4G networks with higher spectral efficiency is an inevitable trend for 5G-oriented evolution. This can reduce O&M costs and improve operation efficiency.

Thirty operators, including NTT Docomo, Korea Telecom, and AT&T, have shut down their 2G or 3G networks, and another ten-plus operators have announced their plans to shut down 2G or 3G networks in the next five years. In addition, the terminal industry has prepared for the migration of 2G and 3G services to 4G networks. VoLTE-capable feature phones have been launched at a price of lower than 20 USD. As IoT services are difficult to migrate, NB-IoT networks have been widely deployed for new IoT connections. The price for NB-IoT modules has dropped to 3 USD, which is comparable to GSM modules.

2. LTE evolution + 5G NR is the future-proof target network, allowing LTE and NR to evolve in parallel.

The 3GPP Release 15 frozen in June 2018 determined that LTE and NR would complement each other and evolve in parallel. LTE evolution is one of the integral parts of the 5G era.

The LTE+NR architecture defined in 3GPP specifications allows for quick 5G NR deployment using LTE coverage and the existing network facilities. E-UTRA-NR Dual Connectivity (EN-DC) exerts ubiquitous LTE coverage to provide superior 5G user experiences. With uplink and downlink decoupling for coordination between LTE and NR, the uplink LTE spectrum can be used to compensate for the insufficient coverage in NR high-frequency bands. The VoLTE technology enables quick voice service provision over 5G NR.

It is also important to highlight that it will take a long time for 5G NR to provide nationwide continuous coverage. Before that, enhanced LTE networks can guarantee optimal user experience for 5G users even when the users leave NR coverage areas. This also enables uninterrupted high-speed 5G services such as VR, AR, and cloud gaming.

3. With a growing number of users and boosting data traffic, LTE will still carry most data services for a long period of time in the 5G era.

715 commercial LTE networks have been deployed worldwide, serving 3.2 billion users. With advantages in terms of coverage and ecosystem, LTE will still be the main bearer for data services in the early 5G era. According to GSMA Intelligence, the number of LTE users is forecast to increase by 2.3 billion by 2025. ABI Research predicted that the proportion of MBB traffic carried on LTE networks will grow from 67% to 82% by 2022. LTE will become the optimal bearer for surging data traffic before the large-scale commercial deployment and maturity of 5G NR.

Therefore, LTE evolution is crucial to operators' success in the 5G era. LTE networks and technologies need to be continuously evolved. In the face of the imminent 5G era, how should operators promote LTE evolution?

First, operators should enhance LTE coverage and enable VoLTE to achieve “zero fallback”.

LTE coverage is still smaller than 2G and 3G coverage. According to GSMA Intelligence, LTE covered 78% of the global population in 2018, lagging behind 2G and 3G, with coverage exceeding 90% of the global population. As a result, a large amount of data falls back to 2G or 3G networks in areas with no LTE coverage.

The VoLTE service provisioning rate or coverage is insufficient. As a result, voice services of 4G users fall back to 2G or 3G through CS Fallback (CSFB). Consequently, data also falls back to 2G or 3G for a short period of time.

Operators can accelerate 2G and 3G spectrum refarming to align LTE coverage with 2G and 3G networks. In addition, VoLTE can be enabled to achieve “zero fallback” for 4G services, laying a foundation for future 2G and 3G service migration and spectrum refarming.

Second, operators should improve network capacity and user experience to construct a “zero wait” foundation network for NR.

According to Analysis Mason, the global average handset data traffic per user per month (DOU) has reached 2.7 GB, and this figure will increase over the next few years at a compound annual growth rate (CAGR) of 50%. LTE capacity is facing unprecedented challenges. According to OpenSignal's data, the average global LTE user experienced data rate has been declining since 2017 as the network load increases. The average rate decreased from 17.5 Mbps in September 2016 to 16.2 Mbps in October 2017.

With the rollout of new services such as ultra-HD video, VR, and mobile gaming, users have higher experience requirements. Currently, the user experienced data rate of major operators around the world has reached 20 Mbps. In the not too distant future, a data rate of 50 Mbps anytime anywhere with “zero wait” time will become a basic requirement.

In addition to traditional capacity expansion, LTE technologies need to evolve to achieve zero-wait experience. Technologies such as Massive MIMO, Massive CA, and Short TTI can be introduced to achieve higher spectral efficiency and better user experience.

Third, operators should reconstruct their networks towards the 5G-oriented target network where the antennas, RF modules, and spectrum are ready for NR deployment. The main challenge in 5G NR deployment is insufficient antenna installation space. 70% of existing sites have no room for new antennas. It is recommended that 1+1 antenna modernization be used to support all frequency bands of the target network: one antenna for all Sub3G frequency bands and the other using C-Band Massive MIMO. In subsequent network reconstruction, Sub3G RF modules need to be NR-ready, avoiding on-site mounting during NR deployment in the distant future. These RF modules should also support dynamic spectrum sharing between LTE and NR to dynamically adjust the Sub3G spectrum resources allocated to LTE and NR based on their respective traffic volume.

Figure 1:

Huawei continuously develops innovative technologies for LTE evolution to help operators unleash LTE potential and pave the way towards 5G success.

In recent years, Huawei has continuously developed the following innovative technologies for LTE evolution:

  • The industry-first Smart Massive MIMO, 4T6S, and TDD 8T8R soft split solutions for improving network capacity.

    • The exclusive SuperBAND solution provides 5G-like large bandwidth, achieving “zero wait” user experience.

    • The industry-first CloudAIR solution enables quick refarming of GSM and UMTS spectrum to LTE, achieving “zero fallback” for 4G services.

    • A series of NR-ready hardware and the 1+1 antenna solution to meet operators' requirements for 5G-oriented network reconstruction.

    • The CloudAIR3.0 solution enables dynamic spectrum sharing between LTE and NR. With this solution, NR and TDD can be simultaneously deployed on the C band or 2.6 GHz frequency band at the early stage of 5G deployment, and the Sub3G spectrum can be refarmed for NR deployment in the distant future. In the coming 5G era, Huawei will continue to work with operators to develop innovative technologies for LTE evolution. Huawei aims to help operators improve LTE network operation efficiency, protect their investments, and pave the way towards 5G success.

      For more information about LTE evolution, please click this link to download the LTE evolution white paper.

      Huawei Technologies Co. Ltd

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