by A.B.Kamalesh (III Year – Computer Science and Engineering), Sastra University, Tamil Nadu
5G or 5th generation of wireless technology is a new global wireless standard after 1G, 2G, 3G and 4G networks. The proprietors of 5G technology promise that, if all components of 5G are fully functional, there will be need of no wired medium to deliver communications even to fixed devices like HDTV, smart appliances, etc. It is designed to produce the optimum solution to the classic “last mile” problem i.e. delivering completely digitalised connectivity from tip of carrier network to customer.
Evolution of 5G
1G or first generation of wireless device delivered analog telecommunication in which voice was carried over unencrypted radio waves. Anyone with a radio or any other component with radio wave detection ability can hear the message. It was devised in late 1970s
The second generation or 2G wireless network introduced digital voice using Code Division Multiple Access (CDMA) which introduced the ability to text messages. 2G was associated with rise of cellular technology Global System of Mobile communication (GSM). Using CDMA was beneficial for efficient use of wireless spectrum and encrypted the messages to be sent, hence enforcing security. The speed of the network was on par with dialup internet.
3G or third generation wireless technology brought in mobile and wireless internet connection which was very crucial in revolution of smartphones. It gave a bandwidth boost using CDMA2000 protocol giving speeds at Mbps for the first time with a peak of 30-40 Mbps. Hence, it was associated with a technology called UMTS or Universal Mobile Telecommunication System because of higher networking speed which makes it possible to have faster download speeds and real-time video calls.
After an interim between 3G and 4G was called 3.5G which was stepping stone for 4G. 4G or fourth generation, usually called as 4G LTE, uses OFDM (Orthogonal Frequency Multiple Division Access) in 3Ghz band. It introduced the concept of mobile broadband i.e. extending wireless internet through portable modems like USB wireless modem, smartphones and tablets, etc. The LTE-A version made it possible to access application servers with reduced delay and made triple-play traffic possible wirelessly anytime, anywhere.
Using the capabilities and improvement of all the before generation, 5G or fifth generation technology has come into existence. The speed is estimated to be 10Gbps which is 10 times faster than Google Fiber’s home standards. It is built over same networking principles as 4G LTE but enhances its flexibility and scalability.
1. Millimeter Wave Communication
To achieve 1000x speed enhancement, 5G will bring in wider bandwidths. It expands the use of spectrum of user resources form sub-6GHz to mmWave (24 GHz and up) different to the current technology saturated at 750 – 2600 MHz spectrum. In addition to this, forming massive MIMO beams on unlicensed spectra and providing radio resources through cloud will lead to faster transfer rates and guaranteed availability. Hence, ultra-low latency communication will be possible.
2. Energy Efficiency
Every new network requires to be energy efficient. Therefore, reduction in energy is a major aspect of 5G. 5G is expected 90% reduction in network energy usage. Researchers have studied different stacks of candidate 5G frameworks. These stacks include network defined MAC, network functional virtualisation, cell size reduction. Some efforts include separating logical separation of control and data planes to create a heterogeneous network. Cloud resource allocation should be done sensibly to reduce idle time and hence energy.
According to communication principles, shorter the frequency, larger the bandwidth. The use of shorter frequencies such as millimeter waves, boosts the speed to 10 Gbps data rate, which is 10-100x speed improvement over 4G. This also comes with added advantages of more availability, high coverage, extension of battery life for low power IoT devices. This essential means that a 4k-HD movies can be downloaded in 25 seconds
The architecture for software defined 5G network has a well-connected core network called 5G core (5Gc) and cloud-RAN.
Cloud-RAN is an idea for decomposing radio signal processing stack into functions so that they can be individually deployed on virtualized cloud environments. Since, analog elements are non-virtualizable, they are deployed on site. These digital and analog elements are interconnected by baseband digital-to-analog and analog-to-digital conversion function. This 5G system decomposition will create new interfaces, known as “RAN splits”, which will be used to interconnect cloud functions among themselves and with cell site functions. The performance of such mm-wave RAN, in Giga KOREA 5G project has been evaluated.
5G core is shifted from high-speed fibre connectivity to mm-wave backbone. Even the interconnected base stations should have high bandwidth connections. 5GC is designed to be modularised as User Plane Functions (UPFs) and Control Plane Functions (CPFs). The UPFs are threaded to Session Management Functions and other backend functionalities. CPFs communicate through a software bus which uses JSON/HTTP2 messaging protocols to map into microservices based cloud service environment.
5. Modulation Techniques
Features of the mentioned candidate waveforms are:
- GFDM or Generalized Frequency Division Multiplexing is a block-based approach which combines both OFDM and Single Carrier Frequency Division Multiplexing. The modes can split the bands into smaller number of subcarriers with wide individual bandwidth or narrow band subcarriers. Hence it reduces synchronization issues.
- BFDM or bi-orthogonal frequency-division uses a relaxed orthogonality mechanism in which transmitter and receiver pulse are pairwise orthogonal and not individually orthogonal. Due to this frequency offset advantage, it is more robust than OFDM.
- FBMC or Filter Bank Multi Carrier provides flexible resource allocation in both frequency and time domains. It uses Preamble Burst approach for resource allocation and is proven to give better results in air interface.
- UFMC or Universal Filtered Multi-carrier counters the loss of orthogonality problem at receiver end. This differentiated from FMBS as it can account for short burst communications. Instead of cyclic prefix as in OFDM it uses sub-band filters.
Challenges in evolving to 5G
- All parts must be Functionally ready – Since the network is said to be fastest as it’s slowest link, so every functional component in the network has to be fast in order to support 5G speed.
- Distributed Cloud-Based Architecture – Edge computing is the crux of the 5G architecture. There should be perfect load-balancing between centralised and edge cloud components and their interconnections to pull out this architecture with the aforesaid ultra low latency.
- Security – Security is required at every edge (switch/router), cloud and database/ warehouse. This means security should be implemented at every step of network operation so that data is not used for unintended purposes.
- New Services – Spectral efficiency depends on the kind of modulation and multiple access scheme used. OFDM used for 4G network is used as a baseline for 5G multiplexing. Similarly, OFDMA surpasses CDMA used in 3G by providing lesser inter-block interference and high peak-to-average-power ratio. 5G NR air interface is based on OFDM principles with high scalability and flexibility. However, application of OFDM over wide band mmWave is not certain. Researchers are devising new modulation techniques such as GFDM, BFDM, FBMC, UMFC etc. The package for 5G offers gigabits per second and has reliability, speed and latency added to it. This package must be set specifically for devices and sensors that support 5G connections. This means to prepare for operating new service models. The best way to do this is through AI and automation techniques.
The rollout of 5G will provide advances in three application specific domains:
Ultra-Reliable Low Latency Communication Use Cases
The ultimate goal of Autonomous vehicles is to automatically respond to instantaneous changes in their surrounding environment. Due to reduced latency, communication between the devices will be 10 times faster over cellular networks.
Smart City and Traffic Management
Many cities around the world are deploying Intelligent Traffic Management Systems (ITS) to promote safety. These systems are the based on the concept of Vehicle route congestion and emergency routes. Introduction of 5G will provide high throughput, reliability and low latency to enable bi-directional communication between vehicles and communication between vehicle and the infrastructure. Therefore, the communication backbone for the vehicle technology will be boosted by deployment of 5G.
Augmented Reality and Virtual Reality
Again, the low latency advantage of 5G will make the AR/VR more interactive and immersive. For a cloud-based server to provide real-time sensory and believable interaction, at least 5 gigabits per second is required. In addition to it the compute intensive workload for AR/VR can be carried out by edge computation i.e. servers stationed near users, pretty suitable for 5G architecture.
Massive IoT Applications
Industry 4.0 relates to IoT providing support for industrial services such as manufacturing and delivers horizontal and vertical integration for different levels of automation pyramid. These applications today working on cables and Wi-iF, don’t have long range mobility and QoS. 5G can make it fully wireless and at a high speed, enabling efficient automation. It will also provide real-time sensing to robots which will again reduce human interference from production line.
IoT for Drones
Today, in addition to video and photography, drones are used for varied application. Logistic companies aim at using drones for delivering goods to varying destinations. But in today’s scenario, drones are limited to site and range of controllers. Introduction of 5G will extend the reach of controllers beyond kilometres through end-to-end edge computation. These advances will have secure benefits in military applications as well.
High Speed Use Cases
Higher bandwidth availability will allow streaming in 4K and 8K in videos in future. It will also allow 360 degrees immersive experiences which means, as a viewer, we will be able to control the angles from which we want to look around.
Enhanced Mobile Broadbands
It aims to service the metropolitan areas with downlink speed of 1 Gbps indoors and 300 Gbps outdoors through the use of mmWaves. These antennas can be installed in lamp posts, side of buildings, branches of trees and mobile or other electronic towers. Even for the suburban and rural areas it can provide 50 Mbps downlink speed.
Cloud and Connectivity
5G will also change the view of connectivity from business point of view. Due to high speed, low latency and high coverage, we will be able to store data in cloud-based infrastructures instead of using on-premise servers. This will give a feel as if the app or data is on local device but instead using these high-end applications it can be accessed as fast. This will largely reduce wiring related costs and cost of installing on premise servers.