# 5G Technology

## Summary


5G is next big evolution in cellular networks from its previous technologies of LTE, UMTS, and GSM. 5G is simply named as 5G, unlike 4G aka LTE, or 2G aka GSM. 5G offers very high throughput with ultra-low latency and more connected devices. With these new capabilities, 5G can support diverse applications including AR/VR, IoT, autonomous driving, 4K streaming, and more. 

Millimeter Wave, Small Cells, Massive MIMO, Beamforming, and Full Duplex are the foundations of 5G. Major changes seen in 5G architecture is with network elements, signal processing, interfaces between network elements, and protocol stack. 5G also migrates from traditional telecom-style protocol interfaces to a *Service-Based Architecture (SBA)* that uses web services and APIs. 

5G was first standardized in 3GPP Release 15 specifications (2018). First commercial 5G networks were launched in April 2019.

## Discussion

### What are the key features or capabilities of 5G?

A comparison of 5G with 4G is insightful into what 5G has to offer. 5G improves on 4G in terms of latency (1 ms vs 10-50 ms), throughput (20 vs 2 Gbps), spectral efficiency (100 vs 30 bps/Hz), density (1M vs 100K conns/km²), traffic capacity (1000 Mbps/m² vs 10 Mbps/m²), and network energy efficiency (15% savings). 

Another source lists 5G capabilities as promising up to 10 Gbps in data rate; 1 millisecond latency; 1000x bandwidth per unit area; 100x device density compared to 4G; 99.999% availability; 100% coverage; 90% energy savings; and up to 10-year battery life for low-power IoT devices. 


### How is 5G technology able to promise 1000x data throughput?

Capacity in cellular systems is the number of bits that can be carried per second per unit area within a given spectrum. It's dimensions are bits/s/km². In general, capacity is composed of three parts: **cell density**, **spectral efficiency** and **available spectrum**. 5G improves capacity by improving each of these parts. Back in 2011, Nokia proposed to achieve 1000x by improving each part by 10x. In 2012, SK Telecom proposed improvements in the order of 56x, 6x and 3x. 

Cell density can be increased provided interference is managed. Spectral efficiency can be improved by using an array of antennas so that all users in a cell can be sending/receiving at the same time using narrowly focused beams. This is what *Massive MIMO* is all about. Finally, more spectrum can be obtained if we go to millimeter waves, usually in the range of 30-300 GHz. However, this requires new hardware and signal propagation is limited. 


### What are the main techniques that make 5G possible?

We note the following technical foundations of 5G: 

    + **Millimeter Wave**: This refers to spectrum bands above 24 GHz. The abundant spectrum available at these high frequencies is capable of delivering extreme data speeds and capacity that will reshape the mobile experience.
    + **Massive MIMO** : Uses large antenna arrays at base stations to simultaneously serve many autonomous terminals. The rich and unique propagation signatures of the terminals are exploited with smart processing at the array.
    + **Beamforming** : Beamforming is a type of RF management in which an access point uses multiple antennas to send out the same signal. It ensures efficient data-delivery route to a user and reduces interference to other users. Along with massive MIMO, beamforming improves spectrum efficiency and capacity.
    + **Full Duplex** : This allow us to transmit and receive on same channel. Benefits include more spectrum efficiency, symmetric fading characteristics, better filtering, novel relay solutions and enhanced interference coordination.
    + **Small Cell** : Small cells are low-power miniature base stations. They operate in licensed or unlicensed spectrum, based on cellular technologies or Wi-Fi. Small cells can help 5G achieve 1000x throughput.

### What are some use cases and applications of 5G?

ITU has identified three main categories of 5G applications based on performance attributes: 

    + **Enhanced Mobile Broadband (eMBB)**: Enables large volumes of data transfer and extreme data rates. Applies to mobile phones, tablets and laptops. Covers human-centric use cases.
    + **Massive Machine Type Communications (mMTC)**: Also called *Critical Machine Type Communications (cMTC)*. In the context of IoT and machine communications, this serves massive number of devices of low complexity and bandwidth that send small amounts of data. Good coverage is important. Serves low-cost battery-powered sensors, meters, actuators, trackers, and wearables.
    + **Ultra-Reliable Low Latency Communications (URLLC)**: Like mMTC, this is also machine-centric but with a focus on reliability and latency. Applications include AR/VR, advanced wearables, autonomous vehicles, real-time industrial control, and more.We can also visualize the above applications mapped to a 3D vector space defined in terms of throughput, delay and density. For example, smart sensors would require high density, tolerable delay and only low throughput. Interactive HD TV would require good throughput, delay and density. Thus, there are many use cases that are a hybrid of the above categories. 


### Could you give an overview of the 5G architecture?

**Next Generation Radio Access Network (NG-RAN)** consists of gNB and ng-eNB. *gNB* serves a 5G UE over 5G New Radio (NR), a new air interface developed for 5G. gNB connects to 5G Core, though some can connect to 4G EPC as well. *ng-eNB* connects to 5G Core but serves a 5G UE over 4G radio. 

5G NR brings performance, flexibility, scalability and efficiency to spectrum usage. Spectrum includes low-band (600 MHz), mid-band (3-5 GHz), and high-band (24-86 GHz) regions. 

**5G Core (5GC)** adopts a service-based architecture consisting of many interconnected *Network Functions (NFs)*. Rather than use fixed network elements, all of these can be virtualized in the cloud. Via *Network Slicing*, many virtual networks with different characteristics can reside on the same physical nodes. Automation, programmability, flexibility and interoperability come from this architecture. 

5GC control plane includes AMF (Access and Mobility Management Function) and SMF (Session Management Function). 5G user plane includes UPF (User Plane Function). 5GC implements *Control and User Plane Separation (CUPS)*. This enables it to centralize control plane functions while distributing user planes functions closer to users for better performance. 


### What are some common criticisms of 5G?

To obtain 1Gbps and 1ms performance, we need mmWave 5G. However, at this spectrum, range is limited. Users will get this performance in limited locations within urban areas. Coverage will be spotty. To counteract this, operators may need to install lots of small cells. 5G rollout will come at a high cost, some of which may be passed on to subscribers. New masts, antennas and smartphones will be needed. Batteries may need to be recharged more often. In rural areas, low-band 5G can give better coverage than 4G but can't offer peak 5G performance. 

With increase data rates and integration with IoT devices, 5G poses a data security risk. With many more connected devices, greater use of cloud and virtualization the attack surface increases. 

There have also been hoax theories concerning 5G. This has resulted in some groups distrusting 5G and even damaging 5G infrastructure. In 2020, 5G was linked to the coronavirus pandemic. The use of mmWave spectrum has been linked to cancer. However, it's known that only ionizing radiation at a much higher spectrum (Gamma rays and X-rays) is harmful.  

## Milestones

Mar  
2012

Huawei introduces the concept of "Beyond LTE". Meanwhile, at the initiative of the EU project METIS, a few organizations across the world start discussions on what should follow 4G/LTE networks. These discussions (2012-2014) lead to the first discussions within 3GPP in 2015. 

May  
2013

At 26GHz, **Samsung demos a prototype system** that achieves 1Gbps data rate. From 2013-2015, many more demos follow from Samsung, Ericsson, Nokia, Qualcomm, and others. The intent is to prove the feasibility of technologies that could be used in 5G, including the use of mmWave spectrum. In August 2015, FCC promotes five blocks of mmWave spectrum. 

Mar  
2017

3GPP begins the **standardization of 5G**. However, some requirements concerning Machine Type Communications (MTC) were already completed in earlier standardized features, namely LTE-M and NB-IoT. These were part of Release 13 (2016) and Release 14 (2017). 

Dec  
2017

3GPP approves the first specifications for 5G, called "early drop" of Release 15. Specifically, it ratifies **Non-Standalone (NSA) 5G New Radio (NR)** specification. This enables vendors to start implementing the first 5G products. NSA 5G will allow operators to leverage existing 4G infrastructure. However, it can't support some use cases that require ultra-low latency and higher capacity. 

Jun  
2018

Also part of Release 15, and called "main drop", 3GPP approves many specifications for 5G including the **Standalone (SA)** option. This allows operators without 4G networks to offer 5G service. 

Mar  
2019

3GPP approves "late drop" of Release 15. This might aid in migrating from 4G to 5G, or NSA 5G to SA 5G. However, some vendors and operators don't see this as essential since Release 16 or 17 specifications could offer alternatives.  

Apr  
2019

South Korean carriers SK Telecom and KT Corp become the first operators to launch the **world's first commercial 5G service**. Within an hour later, Verizon launches its own 5G service in the US in Chicago and Minneapolis. Though trials and limited deployments for enterprises happened in 2018, this is the first time 5G commercial networks connect to 5G smartphones. 5G smartphones used in these deployments are Samsung Galaxy S10 5G and Motorola's Moto Z3 with 5G Mod. 

Jan  
2020

Tests by OpenSignal shows Verizon delivering about 700Mbps download speeds in city downtown areas. In low-band 5G, AT&T and T-Mobile achieve speeds of about 60Mbps and 50Mbps respectively. This is better than what 4G can offer for rural areas. In another study from February to April, OpenSignal finds 5G giving better download speeds compared to 4G. This study included networks in the US, UK, South Korea and Australia. 

Mar  
2020

This year sees some **hoax theories** to discredit 5G. 5G is blamed for the coronavirus pandemic, either causing the pandemic, accelerating the spread of the virus or worsening the symptoms. In another incident, mass death of birds in Netherlands is blamed on 5G. Subsequent reports show that this is fake news. The birds died in another place and time due to other causes. 

Jun  
2020

There are now more than 35 countries with 5G service, with claims of faster rollout and adoption compared to 4G. Globally, there are now 114 commercial networks serving nearly **138 million 5G subscribers**. By August, **190 commercial 5G devices** are available in the market. In October, Apple announces **iPhone 12** models with support for 5G. 

Jul  
2020

3GPP finalizes **Release 16** specifications. This adds support for unlicensed spectrum. It improves on latency, power consumption, positioning and cellular-to-vehicle connectivity. Existing features enhanced by Release 16 include MIMO, beamforming, Dynamic Spectrum Sharing (DSS), Dual Connectivity (DC) and Carrier Aggregation (CA). 

2022

3GPP **Release 17** specifications is expected to come out in 2022. It would impact all three use case families: eMBB, URLLC and mMTC. The focus will be on supporting growing traffic requirements, plus customizing NR for specific verticals such as automotive, logistics, public safety, media and manufacturing. 

2023

First specifications of **5G Advanced** are expected to be released in 2023, with standardization work commencing in 2022. 5G Advanced will span releases 18, 19, 20 and 21.