5G is being developed with three broad use case families in mind: enhanced mobile broadband (eMBB), massive machine-type communications (mMTC) and ultra-reliable low-latency communications (URLLC). eMBB focuses on across-the-board enhancements to the data rate, latency, user density, capacity and coverage of mobile broadband access. mMTC is designed to enable communication between devices that are low-cost, massive in number and battery-driven, intended to support applications such as smart metering, logistics, and field and body sensors. Finally, URLLC will make it possible for devices and machines to communicate with ultra-reliability, very low latency and high availability, making it ideal for vehicular communication, industrial control, factory automation, remote surgery, smart grids and public safety applications.
To meet the complex and sometimes contradictory requirements of these diverse use cases, 5G will encompass both an evolution of 4G LTE networks and the addition of a new, globally standardised radio access technology known as New Radio (NR).
Technologies and Frequency Bands
5G NR operates in frequency ranges from below 1 GHz to 100 GHz with different deployments; 3GPP 38.101 FR1 specifying sub-6 GHz bands, and 3GPP 38.101 FR2 specifying mmWave bands. To provide high service quality and optimal reliability, licensed spectrum will continue to be the backbone of the wireless network in 5G, and transmission in unlicensed spectrum will be used as a complement to provide even higher data rates and boost capacity.
Aggregation of LTE + NR has been defined in 3GPP 37.863, termed Dual Connectivity (DC). Like LTE, NR supports QPSK, 16QAM, 64QAM and 256QAM modulation formats, with the addition of л/2-BPSK in UL to enable a further reduced peak-to-average power ratio and enhanced power-amplifier efficiency at lower data rates.
Multi antenna techniques such as Massive MIMO and MU-MIMO are essential for NR deployment. On lower FR1 bands a low to moderate number of active antennas (up to around 32 transmitter chains) can be deployed. On upper FR1 bands a larger number of antennas can be employed in a given aperture, which increases the capability for beamforming and MU-MIMO. For mmWave (FR2) bands, analog beamforming is typically required, which limits the transmission to a single beam direction per time unit and radio chain.
The standardisation of NR started in 3GPP in April 2016, with the aim of making it commercially available before 2020. 3GPP is taking a phased approach to defining the 5G specifications. A first standardisation phase with limited NR functionality will be completed by 2018, followed by a second standardisation phase that fulfils all the requirements of IMT-2020 (the next generation of mobile communication systems to be specified by ITU-R) by 2019. It is likely that NR will continue to evolve beyond 2020, with a sequence of releases including additional features and functionalities.
The first 5G NR commercial deployment was Ooredoo Qatar, with their implementation of an n78 (3500 MHz) 5G network with peak data rates in excess of 1 Gbps advertised.