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5G key technologies from Radio interface, multiple access schemes, 5G Networking to Cognitive networks driving Worldwide Race

Mobile communications systems have evolved through wireless technology innovation into 2G, 3G, and then 4G to keep pace with ever-increasing voice and data traffic. All mobile communication system generations have had a clear key application driver: 1G for analog voice, 2G for digital voice and text messaging, 3G for multimedia and Internet connectivity, and 4G for true mobile broadband.

 

Every generation of wireless technology brought many improvements including speed enabling many new applications. 1G was analog cellular. 2G technologies, such as CDMA, GSM, and TDMA, were the first generation of digital cellular technologies. 3G technologies, such as EVDO, HSPA, and UMTS, brought speeds from 200kbps to a few megabits per second. 4G technologies, such as WiMAX and LTE, have scaled up to hundreds of megabits and even gigabit-level speeds.

 

5G, short for 5th generation mobile networking or 5th generation wireless systems is the latest iteration of cellular technology that will provide seamless coverage, high data rate, low latency, and highly reliable communications. Part of the 5G spec allows 5G phones to combine 5G and 4G channels invisibly and seamlessly to the user. Initially, all 5G networks used 4G to establish their initial connections, something called “non-standalone.” We’re starting to move away from that now into “standalone” networks.

 

A fully evolved 5G system needs to support diverse application areas such as enhanced mobile broadband (eMBB), massive Internet of things (MIoT), and mission-critical communications (MCC) . All these use cases have distinct and partly contradictory requirements in terms of their key performance indicators, making the system concept design, as a whole, extremely complex. In most of the cases, not all of the requirements need to be simultaneously met. Thus, advanced 5G infrastructures move away from a “one architecture fits all” nature towards a “multiple architectures adapted to each service” concept

 

It will increase energy efficiency, spectrum efficiency, network efficiency and act as an information duct to connect billions of Internet of Things (IoT) devices. The upcoming universal specification will support a million connected devices per square kilometer; 1-millisecond latency, or the amount of time a packet of data takes to get from one point to another; higher energy and spectral efficiency; and a peak data download rate of up to 20 gigabits per second.

 

5G is hitting the mainstream fast: According to a GSA report, around 70 countries had 5G networks as of June 2022, up from just 38 in mid-2020. Approximately 15 more have had 5G mobile technology deployed in part. It is expected that 5G will reach 1 billion users in 2022 after just in 3.5 years in use, compared with 4 years for 4G and 12 years for 3G. The total number of deployments increased dramatically during the same time period with 85,602 deployments on November 30, 2021 compared to 17,428 on November 30, 2020, highlighting the degree to which 5G networks scaled during the year.

Global 5G mobile subscriptions were estimated to be more than 660 million by the end 2021, with China accounting for almost 80% of the total, according to Ericsson Mobility report. This growth is being driven by high levels of consumer demand in North America and North East Asia, particularly China; early deployment and commitment to 5G networks; and falling smartphone prices.

5G subscriptions in North East Asia far outstripped any other region in the world, with subscriptions totaling 517 million. China made up 460 million of these or 70% of the global total. By contrast, North America totaled 80 million subscriptions and Europe 33 million.

South Korea is the country that deployed the first 5G network and is expected to stay in the lead as far as penetration of the technology goes, By 2025, almost 60 percent of mobile subscriptions in South Korea are expected to be for 5G networks. A launch in India is expected in 2023 and an auction for 5G bandwidth frequencies kicked off this week.

 

Speedtest Intelligence data from Q3 2021 shows a wide range of median 5G speeds among global capitals. Seoul, South Korea and Oslo, Norway were in the lead with 530.83 Mbps and 513.08 Mbps, respectively; Abu Dhabi, United Arab Emirates; Riyadh, Saudi Arabia and Doha Qatar followed. Stockholm, Sweden and Oslo, Norway had some of the the fastest median upload speeds over 5G at 56.26 Mbps and 49.95 Mbps, respectively, while Cape Town had the slowest at 14.53 Mbps.

 

“Groundbreaking innovations will drive 5G technologies to meet the unprecedented speeds, near-wireline latencies, ubiquitous connectivity with uniform QoE, and the ability to connect massive amounts of devices with each other, all working in unison to provide the user with an immersive experience, even while the user is on the move,” says Samsung 5G vision.

 5G Standards

The primary 5G standards-making bodies include:

3GPP

The 3rd generation partnership project formulates the 5G technical specifications which ultimately become standards. Release 15 was the first release to define 5G implementations. The release also includes a set ongoing 5G studies to explore the next-generation architecture and 5G NR, focusing on enhanced mobile broadband, ultra-reliability and low latency, frequency ranges, and the importance of forward compatibility in radio and protocol design.

3GPP is a global standard for mobile communication. 5G – the new generation in mobile communications, was released in 2019, and as of December 2021, 133 countries around the globe have begun to invest in the technology. 5G networks are the latest 3GPP standard– boasting speeds between 10 and 100 times faster than 4G. The 3GPP decided to set a 100 MHz width in frequencies below 6 GHz and a 400 MHz width in frequencies above 6 GHz as the maximum bandwidths of 5G-only frequencies.

The 3GPP – the primary standards group developing 5G technologies – is putting the finishing touches on its “Release 17” package of specifications. Another noteworthy service that could be enabled by Release 17, according to Qualcomm, is 5G NR-Light. This technology promises to bring low-power, slow-speed Internet of Things (IoT) wireless connections to 5G networks. “They allow efficient support for lower complexity devices such as wearables, industrial sensors and surveillance cameras,” wrote Qualcomm’s John Smee. Other technologies within Release 17 include battery-waving technologies, improved positioning capabilities, and support for some satellite-based services.

IETF

The Internet Engineering Task Force (IETF) partners with 3GPP on the development of 5G and new uses of the technology. Particularly, IETF develops key specifications for various functions enabling IP protocols to support network virtualization.  For example, IETF is pioneering Service Function Chaining (SFC), which will link the virtualized components of the 5G architecture—such as the base station, serving gateway, and packet data gateway—into a single path. This will permit the dynamic creation and linkage of Virtual Network Functions (VNFs).

ITU

Based in Geneva, the International Telecommunication Union is the United Nations specialized agency focused on information and communication technologies. ITU World Radio communication conferences revise the international treaty governing the use of the radio-frequency spectrum and the geostationary and non-geostationary satellite orbits.

The International Telecommunications Union, the United Nations agency overseeing development of the IMT 2020 standard for 5G technologies, has said the upcoming universal specification will support a million connected devices per square kilometre; 1 millisecond latency, or the amount of time a packet of data takes to get from one point to another; higher energy and spectral efficiency; and a peak data download rate of up to 20 gigabits per second.

ITU published the only globally agreed IMT standard for radio interface technologies in February 2021 under the designation Recommendation ITU-R M.​2150. Three technologies met the stringent IMT-2020 performance requirements. Two of those (3GPP 5G-SRIT and 3GPP 5G-RIT) came from the Third Generation Partnership Project (3GPP), while another (5Gi) was submitted by the Telecommunications Standards Development Society of India.

 

Spectrum and Frequency

Multiple frequency ranges are now being dedicated to 5G new radio (NR).

Low-band 5G operates in frequencies below 2GHz. These are the oldest cellular and TV frequencies. They go great distances, but there aren’t very wide channels available, and many of those channels are being used for 4G. So low-band 5G is slow. It acts and feels like 4G, for now. Low-band 5G channels are from 5MHz in width (for AT&T) up to 20MHz (for T-Mobile), so you can see they aren’t roomier than 4G.

 

Mid-band 5G is in the 2 to 10GHz range. That covers most current cellular and Wi-Fi frequencies, as well as frequencies slightly above those. These networks have decent range from their towers, often about half a mile, so in most other countries, these are the workhorse networks carrying most 5G traffic. Most other countries have offered around 100MHz to each of their carriers for mid-band 5G.

 

The portion of the radio spectrum with frequencies between 30 GHz and 300 GHz is known as the millimeter wave, since wavelengths range from 1-10 mm. Frequencies between 24 GHz and 100 GHz are now being allocated to 5G in multiple regions worldwide.

 

3GPP’s new Release 17 promises to expand 5G networks into a completely new spectrum band: 52.6GHz to 71GHz. That’s important considering the 60GHz band is widely available on an unlicensed basis around the world, thus potentially allowing network operators to offer high-speed services in the millimeter wave (mmWave) spectrum bands without needing to acquire new spectrum licenses.

 

They’re very short range; PCmag tests have shown about 800-foot distances from towers. The diversity of frequencies employed can be tailored to the unique applications considering the higher frequencies are characterized by higher bandwidth, albeit shorter range. The millimeter wave frequencies are ideal for densely populated areas, but ineffective for long distance communication.

 

5G Network Architecture

The cellular network provides wireless connectivity to devices that are on the move. These devices, which are known as User Equipment (UE), have traditionally corresponded to smartphones and tablets, but will increasingly include cars, drones, industrial and agricultural machines, robots, home appliances, medical devices, and so on.

 

Like other cellular networks, 5G networks use a system of cell sites that divide their territory into sectors and send encoded data through radio waves. Each cell site must be connected to a network backbone, whether through a wired or wireless backhaul connection.

 

The cellular network consists of two main subsystems: the Radio Access Network (RAN) and the Mobile Core. The RAN manages the radio spectrum, making sure it is used efficiently and meets the quality-of-service requirements of every user. It corresponds to a distributed collection of base stations. In 4G these are (somewhat cryptically) named eNodeB (or eNB), which is short for evolved Node B. In 5G they are known as gNB. (The g stands for “next Generation”.)

 

Backhaul Network interconnects the base stations that implement the RAN with the Mobile Core. For example, the Passive Optical Network (PON) that implements Fiber-to-the-Home is a prime candidate for implementing the RAN backhaul.

 

The Mobile Core is a bundle of functionality (as opposed to a device) that serves several purposes.

  • Provides Internet (IP) connectivity for both data and voice services.
  • Ensures this connectivity fulfills the promised QoS requirements.
  • Tracks user mobility to ensure uninterrupted service.
  • Tracks subscriber usage for billing and charging.

Note that Mobile Core is another example of a generic term. In 4G this is called the Evolved Packet Core (EPC) and in 5G it is called the Next Generation Core (NG-Core).

 

 

The primary goal of previous generations of mobile networks has been to simply offer fast, reliable mobile data services to network users. 5G has broadened this scope to offer a broad range of wireless services delivered to the end user across multiple access platforms and multi-layer networks. 5G is effectively a dynamic, coherent and flexible framework of multiple advanced technologies supporting a variety of applications.

5G network architecture

As shown 5G network uses flat IP concept so that different RANs (Radio Access Networks) can use the same single Nanocore for communication. RANs supported by 5G architecture are GSM, GPRS/EDGE, UMTS, LTE, LTE-advanced, WiMAX, WiFi, CDMA2000, EV-DO, CDMA One, IS-95 etc.

 

5G aggregator aggregates all the RAN traffics and route it to gateway. 5G aggregator is located at BSC/RNC place. 5G mobile terminal houses different radio interfaces for each RAT in order to provide support for all the spectrum access and wireless technologies.

 

Another component in the 5G network architecture is 5G nanocore. It consists of nanotechnology, cloud computing, All IP architecture. Cloud computing utilizes internet as well as central remote servers to maintain data and applications of the users. It allows consumers to use applications without any installation and access their files from any computer across the globe with the use of internet.

 

5G utilizes a more intelligent architecture, with Radio Access Networks (RANs) no longer constrained by base station proximity or complex infrastructure. 5G leads the way towards disaggregated, flexible and virtual RAN with new interfaces creating additional data access points.

 

Protocol layers

5G network architecture | 5G Architecture

OWA Layer: OWA layer is the short form of Open Wireless Architecture layer. It functions as physical layer and data link layer of OSI stack.

Network Layer: It is used to route data from source IP device to the destination IP device/system. It is divided into lower and upper network layers.

Open Transport Layer: It combines functionality of both transport layer and session layer.
Application Layer: It marks the data as per proper format required. It also does encryption and decryption of the data. It selects the best wireless connection for given service. In this layer, intelligent algorithms are used to overcome loss values in parameters such as delay, reliability, losses, bandwidth, and jitter in the 5G handset and to provide Quality of Service (QoS). 5G provides an intelligent behavior facility using a large number of algorithms for selecting the best wireless connection among different networks. In this layer, terminals have information storage and access to quality testing.

 

5G Technology requirements

With spectral efficiency requirements set to 10 bps/ Hz levels (in contrast to the 1-3 bps/Hz on 4G networks), 5G is also expected to deliver efficient use of the spectrum by using MIMO, multiple access, advanced coding and modulation schemes and new waveform design.

 

To meet dramatic traffic growth over the next decade, 5G mobile networks are expected to achieve higher capacity increases compared to 4G networks, with considerably higher-speed data rates. This objective can be accomplished with dense small cell deployment, utilization of the millimeter-wave band, and Multiple MIMO and beamforming.

 

5G supports the 4th generation + wireless world wide web (4G + WWWW). WWWW is used to interconnect the entire world and also capable of supporting services and applications.

 

Enabling Technologies

Some of the technology enablers are

  • Enhanced radio interface using advanced modulation, coding and multiple access schemes. 5G works with Orthogonal Frequency Division Multiplexing (OFDM) encoding wireless communication technique and aims to access high-speed unlimited information anytime and anywhere from any location to the entire world. 5G operates using IPv6 protocol which utilizes Code Division Multiple Access, Beam Division Multiple Access, and millimeter wireless which provides larger than 100 Mbps, 1 Gbps at full speed, low speed respectively.
  • Advanced Antenna and multi site technologies
  • Flexible spectrum usage
  • Simultaneous transmission and reception
  • Technologies that support wide range of emerging services, M2M and group communications
  • Technologies that enhance user experience: cell edge enhancement, QOS enhancement, mobile video enhancement, broadcast and multicast, low reliability technologies, RLAN networking, context aware.
  • Technologies that enhance network efficiency, network level power management, energy efficient network deployment,user-centric resource management and allocation, physical layer enhancement and interference handling.
  • Terminal technologies: interference cancellation and suppression.
  • Network technologies: technologies to simplify management and improve network reliability, network architectures. For 5G to deliver on its promise, it will also need enabling technologies for deploying networks efficiently and flexibly. Some of them are IoT devices,  Network Function Virtualization (NFV), Network Slicing (NS),  Software Defined Networks (SDN), Distributed or Edge Cloud Computing and Artificial Intelligence / Advanced Analytics.
  • Enhance privacy and security

 

Dense small cell deployment

As a baseline, 5G systems will provide gigabit-rate data services regardless of a user’s location as shown. To provide this uniform QoE, 5G network deployments are expected to be much denser compared to 4G networks, so making cost-effective deployment is a very important requisite. Deployment of Small Cells increases network capacity and spectrum reuse. Small cells must be deployed with a limited cell radius to help reuse the spectrum (increase spectral efficiency) and increase the network capacity (as the network resources increase). Small cells (or microcells) serve fewer mobile users but are much easier to install and maintain as well as cheaper, and more energy-efficient.

 

As 5G rollouts gather steam, the deployment is driving the surge for small cells, and it is estimated there will be 1.56 million private 5G small cells deployed by 2027. While it is important to fulfill strict zoning and permitting standards, small cells are getting smaller—smaller radios, more compact antennas, and so forth, to meet performance targets.

 

The inclusion of radically high mmWave radio spectrum in 5G requires beamforming and beam-management equipment at the small-cell BSs. Furthermore, the ultra-dense deployment of cells, i.e., small-cells with cell-radius of only a few meters, necessitates massive infrastructural provisions. Small cell site is more than just the radio and antenna—it’s also about the power distribution, fiber-optic backhaul connectivity, and ideally, battery backup power.

 

Millimeter Wave

5G technologies will need to be capable of delivering fiber-like 10 Gb/s speeds will depend on ultra-wide bandwidth with sub-millisecond latencies. The scarcity of conventional microwave band has led to the exploration of mmWave realm. The multi-gigahertz bandwidth available in mmWave range has a strong potential in addressing the capacity demands of 5G and beyond wireless networks.

 

MmWave spectrum operates in high frequencies found between 30 GHz and 300 GHz, and is attractive for a number of reasons. One advantage in these high frequency bands is availability of wider bandwidth channels. Additional radio spectrum would be available at millimetre wave frequencies from 30 GHz to 300 GHz will provide 10 times more band¬width than the 4G cellular-bands.

 

Second, there is more mmWave bandwidth available, which improves data transfer speed and avoids the congestion that exists in lower spectrum bands (prior to researching potential 5G uses of mmWave frequencies, the only major operators in that area of the spectrum were radar and satellite traffic).  The shorter wavelengths of mmWave create narrower beams, which in turn provide better resolution and security for the data transmission and can carry large amounts of data at increased speeds with minimal latency. Finally, mmWave components are smaller than components for lower bands of the spectrum, allowing for more compact deployment on wireless devices.

 

However, mmWave has its share of challenges. While its short wavelengths and narrowness of its beam allow for improved resolution and security of data transfer, these qualities can also restrict the distance at which mmWaves can propagate. The mm-Wave suffers from more path loss compared to microwaves i.e., due to an increase in frequency, the received power is reduced to low. Secondly, because of the rain and atmosphere, the mm-Wave signal suffers from high absorption losses.

 

This creates a high infrastructure cost, as a mmWave network would require densely populated base stations throughout a geographic area to ensure uninterrupted connectivity. This challenge is further aggravated by the fact that mmWaves can be easily blocked by obstacles like walls, foliage, and the human body itself.

 

There are ongoing efforts to mitigate these physics challenges, such as massive MIMO (multiple-input, multiple-output) and beamforming. To handle narrow beams effectively, mm-Wave systems contain high directional antennas in a large number of arrays which also appropriate for short-range communication. 5G systems use both mm-Wave spectrum and microwave due to limited spatial coverage of mm-Wave.

 

Sub-6 includes the range of spectrum below 6 GHz. Sub-6 can provide broad area network coverage with lower risk of interruption than mmWave due to its longer wavelength and greater capacity to penetrate obstacles. It therefore requires less capex and fewer base stations, as compared to mmWave.

 

Network technologies

5G NR is a new radio interface released by 3GPP to satisfy the growing needs of radio access in future wireless networks. The 5G-NR provides a number of significant new technologies and advantages compared to the 4G networks.

 

The outer edge of a 5G network begins with 5G devices, where smartphones, IoT devices, autonomous vehicles, and other equipment connect to a 5G network to send and receive data.

 

Some of the Terminal technologies include simultaneous transmission and reception and interference cancellation and suppression. Common features of all 5G devices, however, will include 5G-compatible modems for translating data into a form that can be sent via radio waves; 5G radio frequency front end systems (RFFEs) for processing signals transmitted over 5G frequencies; and 5G-compatible antennas for sending and receiving those radio signals.

 

The signals travel through a transport network—known as the backhaul—before reaching the telecom’s core network. The backhaul comprises routers, switches, fiber-optic cables, optical transceivers, and microwave transmission equipment.

 

The router and switch market is currently led by Cisco, Huawei, Nokia, and Juniper, which together account for 90 percent of the market share. Ethernet switches are the most common type of network switches, however, the market for ethernet switches may be overtaken by “white box” routers—generic, low-cost hardware using cloud-based software.

 

Significant components include antenna arrays, data converters, Power transistors for low noise and power amplifiers serving to amplify the signal received by the small cell’s antenna. Small cells also require “field programmable gate arrays” (FPGAs) to connect baseband units and the transport network. Many of these components can be combined into a single “chipset.” Qualcomm Snapdragon 855 chipset, which grants smartphones 5G capabilities.

 

RF components can include subcomponents ranging from semiconductors to switches and amplifiers. Integrated chipsets combine various subcomponents and other subsystems such as integrated modems to interface with system components on a motherboard. Semiconductor technologies considered include SiGe, GaN, GaAs, and CMOS.

 

MMWave also present many challenges including circuit design, and as these frequencies do not travel as far and are absorbed almost completely by obstacles like walls, foliage, and the human body.

 

Advanced Antenna technologies that allow handsets to have both sub-6 GHz and mmWave antenna systems coexisting in the same device while achieving strict performance requirements is a new challenge. Advanced materials can be combined with smart antenna and MIMO technologies to create flexibly performing antennas with ultra-wide bandwidth and high efficiencies.

 

The enormous wide variation in the requirements from superfast downloads to small data requirements for IoT than any one system will not be able to meet these needs. As a result, it will heavily rely on emerging technologies such as cloud computing, Software Defined Networking (SDN), Network Functions Virtualization (NFV), Mobile Edge Computing (MEC) and Fog Computing (FC) to achieve the required performance, scalability and agility to meet the growing user and service demands.

 

Distributed / Edge Computing MEC

Traditional cloud computing offers many economic advantages from centralizing compute server functions particularly by sharing of resources. However, these server farms are often located at remote locations where cost of power and cooling are economically advantageous, which also means that applications that need rapid response / low latency are disadvantaged. Edge computing locates the shared compute resources much closer to the service endpoints like 5G base stations or NFV servers.

 

MEC is an evolution in cloud computing that brings the applications from centralized data centers to the network edge, and therefore closer to the end users and their devices. Mobile Edge Computing (MEC) integrate the computing, storage and networking resources with the base station will empower the network edge to process delay-sensitive and Compute intensive applications like augmented reality.

 

5G networks based on the 3GPP 5G specifications are an ideal environment for MEC deployment. The 5G specifications define the enablers for edge computing, allowing MEC and 5G to collaboratively route traffic. In addition to the latency and bandwidth benefits of the MEC architecture, the distribution of computing power will better enable the high volume of connected devices inherent to 5G deployment and the rise of the Internet of Things (IoT).

 

Software-defined networking (SDN), network functions virtualization (NFV), and network virtualization (NV)

5G will be driven by software. Network functions are expected to run over a unified operating system in a number of points of presence, especially at the edge of the network for meeting performance targets.

 

As a result, it will heavily rely on emerging technologies such as Software Defined Networking (SDN), Network Functions Virtualization (NFV), Mobile Edge Computing (MEC) and Fog Computing (FC) to achieve the required performance, scalability and agility. The focus for 5G will be on building more intelligence into the network, to meet service quality demands by dynamic use of priorities, adaptive network reconfiguration, and other network management techniques.

 

Network Slicing refers to the partitioning of 5G networks to provide dedicated capacity for technologies and applications. For example, network slicing in 5G could provide dedicated resources to IoT devices to ensure that they work effectively in particular areas or industries. Network slicing may also allow for sharing of a capital-intensive 5G network between many operators.

 

This technology adds an extra dimension to the NFV domain by allowing multiple logical networks to simultaneously run on top of a shared physical network infrastructure. Operators can effectively manage diverse 5G use cases with differing throughput, latency and availability demands by partitioning network resources to multiple users or “tenants”. Network slicing becomes extremely useful for applications like the IoT where the number of users may be extremely high, but the overall bandwidth demand is low.

 

Network function virtualization (NFV) decouples software from hardware by replacing various network functions such as firewalls, load balancers, and routers with virtualized instances running as software. Network Functions Virtualization (NFV) uses high-performance computing server farms to implement via software many functions of a wireless infrastructure like the physical and medium access layers that were earlier implemented by dedicated hardware/semiconductors.

 

This eliminates the need to invest in many expensive hardware elements and can also accelerate installation times, thereby providing revenue-generating services to the customer faster.  Those devices include expensive routers and switches that are replaced with a software implemented on high volume servers, switches and storage units located in the clouds. In such way, the cost is deducted, the power and locations of those equipment are saved, and the adaptation of those devices will be facilitated.

 

It focuses on optimizing the network services themselves. NFV decouples the network functions, such as DNS, caching, etc., from proprietary hardware appliances, so they can run in software to accelerate service innovation and provisioning, particularly within service provider environments. In addition, operators can have flexible services based on geographical location and customer privileges. Moreover, resources can be shared in an easier way with other operators located at the same server. NFV will bring enormous savings and flexibility in rolling out 5G wireless networks.

 

Software-Defined Networking (SDN( is another technology that can be utilized to implement wireless virtualization in C-RAN. It separates the network’s control (brains) and forwarding (muscle) planes and provides a centralized view of the distributed network for more efficient orchestration and automation of network services. Network switches are considered as forwarding devices that are monitored by a centralized entity.

 

In traditional IP protocol networks, routers were placed at confluence points to route or switch the flow of packets to ultimately reach the destination node. The associated routing table was based on local knowledge of link congestion which may vary from time to time and the routing logic was determined by the IP address of the destination node. In SDN the routing tables are managed centrally by an entity that has a global view of the network link states. Also, routing strategies can be more flexible than IP address of the destination node. These features allow much more efficient routing, and SDN will be a key technology for 5G.

 

SDN and NFV, complementing each other, enable programmability of control and network functions and eventual migration of these key constituents of the network to the cloud.

 

Cloud RAN

The part of the cellular networks that needs to be modified to handle such growth is called Radio Access Networks (RAN).

 

The virtualization and automation of network functions enable cloud-based deployments of 5G Core Networks which creates exciting opportunities for cloud-native deployments of Radio Access Networks (RAN).  Cloud-RAN functionalities, allow a remote radio head to connect to a cloud server via a fronthaul. Centralizing some of the radio functionalities in a cloud close to the wireless edge has shown substantial cost savings and performance improvements.

 

RAN includes base stations and users connections wirelessly to the system besides handling user signaling and managements.  It is a novel mobile architecture that has the potential to handle as many base stations as the network needs using the concept of virtualization. In C-RAN, the baseband and channel processing is virtualized and shared among operators in a centralized baseband pool.

 

Virtualization technology facilitates the logical isolation of resources while the physical resources are shared in a dynamic and scalable way. Those resources include network, computing or storage resources. From those resources, network virtualization is critical in C-RAN and its deployment architectures. Network virtualization consists of multiple nodes and links that are deployed on the same physical machine. Thus, such technology enables flexible control mechanism, efficient resources, low cost and diverse applications.

 

Cloud Radio Access Network (CloudRAN) reduces costs and facilities efficient allocation of resources. Such centralization and sharing allows for more dynamic traffic handling and better utilization of resources including base stations deployments. Such architecture would have the potential to decrease the expenses cost as base stations are virtualized instead of physically deployed in different areas. In addition, it reduces the energy and power consumption compared to traditional networks due to the fact that base stations will be located on the same physical device. Therefore, C-RAN architecture was highly appreciated and targeted by mobile operators including China Mobile, IBM, Huawei, Nokia Siemens Networks, Intel and many more.  A cRAN architecture has three primary components — a centralized baseband unit (BBU) pool, remote radio unit (RRU) networks, and transport network or fronthaul.

 

Fixed Wireless allow for cellular coverage within buildings and homes by communicating with microcell towers through fixed wireless antennas placed on top of homes and buildings. Specially designed modems and routers can convert the wireless signal to conventional Wi-Fi.

 

Multiple Access Schemes

Next generation wireless networks require massive uplink connections as well as high spectral efficiency. It is well known that, theoretically, it is not possible to achieve the sum capacity of multi-user communications with orthogonal multiple access. To meet the challenging requirements of next generation networks, researchers have explored non-orthogonal and overloaded transmission technologies–known as new radio multiple access (NR-MA) schemes–for fifth generation (5G) networks.

 

There are several candidate systems that are being considered as the 5G multiple access scheme. They include a variety of different ideas. The key feature of codebook based MA schemes is the direct mapping of each user’s data stream into a multi-dimensional codeword in a codebook. The codeword has two characteristics: i) signal spreading to obtain diversity/shaping gain, and ii) ‘zero’ elements in a codeword to suppress inter-user interference in a sparse manner. The positions of zero elements in different codebooks are distinct so as to avoid a collision of any two users.

 

Two schemes that belong to this category are sparse code multiple access (SCMA) and pattern division multiple access (PDMA). The main difference between SCMA and PDMA is the resource-utilization pattern. SCMA codewords in all codebooks have the same number of zero/non-zero elements as a regular pattern. In contrast, the PDMA system allocates a different number of non-zero elements by considering each user’s channel state. For example, to obtain a high diversity gain for a user with a weak channel gain, the PDMA can assign a codebook with more non-zero elements than those of another codebook.

 

Orthogonal frequency division multiple access, OFDMA

OFDMA has been widely used and very successful for 4G and could be used as a 5G multiple access scheme. However it does require the use of OFDM and requiring orthogonality between carriers and the use of a cyclic prefix has some drawbacks. As a result other multiple access schemes are being investigated.

 

Sparse Code Multiple Access, SCMA

SCMA is another idea being considered as a 5G multiple access scheme and it is effectively a combination of OFDMA and CDMA. Normally with OFDMA a carrier or carriers is allocated to a given user. However if each carrier has a spreading code added to it, then it would be able to transmit data to or from multiple users. This technique has been developed to use what are termed sparse code and in this way significant numbers of users can be added while maintaining the spectral efficiency levels.

Non-orthogonal multiple access, NOMA

The provision of wireless medium’s access to multiple users was conventionally achieved through the allocation of (sliced) distinct channel resources (time, frequency, or code, etc.) among the users and spatial re-utilization of the resources. The massive growth in the number of network users and the limited availability of usable frequency spectrum has led towards the evolution of multiple-access methods from orthogonal to non-orthogonal resource allocation based methods. The NOMA scheme allocates non-orthogonal channel resources to the users while exploiting an additional dimension/domain of power. Signal processing methods for channel estimation and interference suppression are the prime operations required in NOMA transceivers.

 

NOMA superposes multiple users in the power domain, using cancellation techniques to remove the more powerful signal. NOMA could use orthogonal frequency division multiple access, OFDMA or the discrete Fourier transform, DFT-spread OFDM.

 

Novel sequence-based MA techniques utilize nonorthogonal complex number sequences to overlap multi-user signals as shown. This method contrasts with that of using orthogonal pseudo noise sequences in a code division multiple access (CDMA) system. The key issue in sequence-based MA is how to design and assign non-orthogonal sequence sets to users. In multiuser shared access (MUSA), the real and imaginary parts of sequence elements are randomly generated from {-1, 0, 1}. Thanks to the zero elements in the sequences, inter-user interference is efficiently mitigated as in the codebook-based MA.

 

In fact, in the Third Generation Partnership Project (3GPP), NTT DOCOMO introduced the power domain non-orthogonal multiple access (NOMA). The NOMA allows multiple users to share the same radio resources. NR-MA schemes may be described as a user overloading technology that expands a capacity region. The key is how well a large number of users’ signals are superimposed and recovered within a controllable and acceptable amount of interference. An important metric for the NR-MA in this regard is the overloading factor defined as the ratio of the number of overloaded signals to that of orthogonal resource grids.

 

Full-Duplex

Full-duplex is a key 5G technology, which theoretically has the potential of doubling the channel capacity through the concurrent transmission and reception of information in a single channel resource. The performance of full-duplex method relies on the performance of self-interference-cancellation methods, which may practically be performed through active analog/digital cancellation or passive cancellation methods

 

Artificial Intelligence / Advanced Analytics

The recent advances in communication network technologies, proliferation in the number of connected devices, and growing multimedia applications are leading towards a flourishing expansion in the data generation. The radio communication networks are not only the carriers but also a leading source of generation of data. Appropriate exploitation of big data analytics has a strong potential in facilitating the improvement in the performance of the communication systems as well as in maximizing the revenue generation opportunities for the stakeholders.

 

The number and variety of 5G links will increase by 100X over those supported in current 2G, 3G and 4G networks. This will both complicate network management, anomaly/ fault detection and optimization. The role of machine learning and advanced analytics will vastly increase in 5G networks.

 

The data-aware intelligence for extracting useful information from the data and enhancing the network performance for IoT applications have been discussed. Also, a collaborative processing framework while combining the benefits of edge and cloud computing for live data anaytics in IoT networks has been proposed. Along with the benefits offered by big data analytics, there are also various critical concerns being raised regarding the ethics of the analytics

 

The heterogenous nature of future wireless networks comprising of multiple access networks, frequency bands and cells – all with overlapping coverage areas – presents wireless operators with network planning and deployment challenges. Machine Learning (ML) and Artificial Intelligence (AI) can assist wireless operators to overcome these challenges by analyzing the geographic information, engineering parameters and historic data to:

  • Forecast the peak traffic, resource utilization and application types
  • Optimize and fine tune network parameters for capacity expansion
  • Eliminate coverage holes by measuring the interference and using the inter-site distance information

 

Multiple Input Multiple Output (MIMO)

Multiple Input Multiple Output (MIMO) wireless multiplies data rates by using multiple antennas both at the transmitter and the receiver to enable ‘Spatial Multiplexing’ that creates parallel data streams equal of the number of antennas. MIMO therefore effectively multiplies the radio spectrum, a scarce and a very expensive resource. The technique requires special encoding of signals at the transmitter and corresponding decoding of the entangled signals at the receiver.

 

Current LTE and WiFi systems support eight MIMO streams. 5G networks are moving to millimetric band spectrum will allow the use a much larger number of antennas. This will boost MIMO leverage by 100X or more in the next few years. In 4G systems, where the number of the antennas supported at the base station (BS) cannot be larger than 64,

 

Massive (or Very Large) MIMO techniques use more than 100 antennas for high performance gains.  This technique has a big potential. A massive MIMO technique can increase 10 times or more channel capacity and improve 100 times or more energy efficiency. MIMO technique is well matched at a high frequency technique such as millimeter wave (mmWAVE) techniques.

 

Massive MIMO is an antenna array that will greatly expand the number of simultaneous connections and throughput, and will give base stations the ability to send and receive signals from many more users at once and increase the capacity of networks significantly, assuming multiple RF paths to users exist.  Beamforming is a technique for identifying the most efficient data-delivery route to a particular user and reducing interference for nearby users in the process.

 

These options can improve the propagation of mmWaves, but challenges remain with maintaining connectivity across a broader area using this part of the spectrum. Significant time and R&D will have to be devoted to solving the mmWave propagation problem before it can be deployed as a more universal wireless network solution.

 

Beamforming

Another breakthrough technology integral to the success of 5G is beamforming. Conventional base stations have transmitted signals in multiple directions without regard to the position of targeted users or devices. Through the use of multiple-input, multiple-output (MIMO) arrays featuring dozens of small antennas combined in a single formation, signal processing algorithms can be used to determine the most efficient transmission path to each user while individual packets can be sent in multiple directions then choreographed to reach the end user in a predetermined sequence.

 

Beamforming is a technique in which the base station computer will continuously calculate the best route for radio waves to reach each wireless device and will organise multiple antennas to work together as phased arrays to create beams of millimeter waves to reach the device. Mobile networks require antenna units to capture signals from user devices as well as a host of electrical processing components to clean, amplify, modulate, and route incoming and outgoing RF signals. With 4G, this process was done by “baseband processing units” (BBUs) co-located with the cell towers. For 5G networks, however, network processing activities are predicted to move away from cell site towards centralized, cloud-based BBUs.

 

Millimeter Wave Antennas

Given that current mobile phones operate in frequencies between 0.8 to 2.5 GHz, they are capable of download speeds of only 230 Mbps. Therefore, mobile devices operating in the millimeter-wave band are essential to cope with the higher-speed data transmissions required from 5G.

 

The considerably high propagation loss of mmWave makes it suitable for dense small cell deployment, which leads to higher spatial reuse. In these bands, the cell sizes also drop to < 200 Meters. However, the challenge is how to overcome the additional signal losses which could be compensated for using beamforming and a larger antenna array. Beamforming is the concentration of power in a certain direction with a limited beam width but a large gain. The use of the millimetre wave frequency band, which is 30-300GHz, will have significant implications for chipset makers, In particular, the general switch from CMOS to gallium arsenide and gallium nitride process technologies.

 

Adaptive Antennas

Adaptive antenna systems represent a significant element of design for enhanced small‐cell deployment. These kinds of adaptive antenna systems can enable extension of transmission range, increase of data throughput, enhance spectrum reuse, and substantially reduce co-channel interference which is one critical issue in future heterogeneous wireless communications systems . Adaptive antenna systems can steer the main beam in a desired direction and spatial nulls in undesired directions to avoid interference.

 

A breakthrough in 5G networking

With its 5G CPE router, the leading innovator Huawei has just released the world’s first commercial end device for the new 5G wireless mobile standard. Available in both indoor and outdoor units, its 5G CPE router features the specially developed Balong 5G01 chipset – the world’s first commercial chipset to support the 3GPP standard for 5G, reaching possible downlink speeds of up to 2.3 Gbps. What’s more, the device is designed to support all frequency bands including sub-6 GHz and millimeter wave (mmWave), making Huawei the first company to combine network, device and chipset functions in one end-to-end 5G solution.

 

SK Telecom to offer 10x faster processing breakthrough for 5G standardization consideration

SK Telecom has developed a “breakthrough technology” that will help 5G process data traffic 10 times faster than LTE, and it’s hoping the 3GPP and ETSI will adopt it as part of the global 5G standard. In the existing LTE network, the maximum speed for packet switching per server is 20 gigabits per second. With this technology, the speed will reach 200 gigabits per second at the same server and can even break the terabit-per-second barrier with the addition of virtual servers, according to the mobile operator.

 

SK says the network innovation it developed is the world’s first implementation of the terabit-per-second capability for packet switching. In addition, the new technology helps make packet switching equipment compact, so network operators can deploy them at base stations and therefore implement ultralow latency for more traffic in 5G services.

 

“Ultra-fast packet processing technology is essential in delivering best quality of 5G services,” said Park Jin-hyo, senior vice president and head of Network Technology R&D Center at SK Telecom, in a statement. “It is a significant result for SK Telecom as this virtualization-based high performing equipment could enable us to deliver a faster, efficient 5G rollout.”

 

5G Phones Get Closer with Qualcomm’s mmWave Antennas

In July 2018 , Qualcomm unveiled  5G millimeter-wave module  t— the QTM052 mmWave antenna module family and the QPM56xx sub-6 GHz RF module —  the first fully-integrated 5G NR millimeter-wave and sub-6 GHz RF component built for mobile. They can offer modem-to-antenna capabilities across different spectrum bands. And because the modules are so small, they integrate easily into mobile devices — so much so that Qualcomm actually built it so that up to four modules can be included on a phone.

 

With these part now available to Qualcomm’s phone-building partners, we’ve just taken a big step toward 5G-capable devices landing in the hands of consumers, Qualcomm says. “Because these modules exist, millimeter wave-capable smartphones can exist,” Hanna said. “And because millimeter wave-capable smartphones, the [5G] networks can launch.”

 

Signalchip unveils India’s first indigenous semiconductor chips for 4G/LTE and 5G NR modems

Bengaluru-based fab-less semiconductor company, Signalchip, unveiled in Feb 2019, India’s first semiconductor chips for 4G/LTE and 5G NR modems in the presence of Telecom Secretary Ms. Aruna Sundararajan. The combined multi-standard system on chip (SoC) can serve as a base station chipset for a wide range of form factors from low-cost indoor small cells to high performance base stations. These are optimally designed to support evolving network architectures like Open RAN/CRAN with flexible interface configurations.

 

SCRF4502: 2X2 5G NR/LTE/WCDMA Analog-RF transceiver chip:

This device builds on SCRF3402 to add 5G NR features and extends the capabilities of the complete transceiver chain including low noise amplifiers, power amplifier interfacing with the antenna, filters, high speed data converters, frequency synthesizers, and mixers to meet the requirements of 5G NR Frequency Range 1. Owing to the high degree of integration, this device can enable a compact form factor RRU for 5G massive MIMO and RAN systems.

 

5G phased array antenna

A phased array uses an antenna element arrangement so that the relative phase of each element is varied to steer a radiation pattern or beam. The antennas are connected by a system of microwave transmission lines and power dividers. A phased array antenna is designed to control the direction of an emitted beam by exploiting interference between two or more radiated signals, or “beamforming.” The antenna enables beamforming by adjusting the phase difference between the driving signal sent to each emitter in the array. The number of emitters in a phased array antenna range from a handful to literally thousands.

 

A phased array antenna is critical for 5G to achieve wider bandwidths, coverage, and greater capacity in the millimeter-wave spectrum. Although millimeter-wave systems are relatively easy to deploy in short-range indoor applications, their use outdoors, however, results in propagation loss, rain fades, atmospheric absorption, and high attenuation and shadowing.

 

Ericsson and IBM were named as the ISSCC (International Solid-State Circuit Conference) 2017 Lewis Winner for a research breakthrough unveiled in February 2017. The two companies created a compact silicon-based chip, or Radio Frequency Integrated Circuit (RFIC), on 28 GHz and designed a Phased Array Antenna Module (PAAM) to integrate four of these chips for use in future 5G base stations.

 

As part of their two-year collaboration on 5G, Ericsson and IBM developed an integrated circuit with a phased array antenna module that operates on the 28GHz spectrum band, to be used in 5G base stations. mmWave bands, portions of the electromagnetic spectrum, allow for speeds that are more than 10 times faster than the frequencies used currently for mobile devices.

 

The 2.8×2.8-inch device has four monolithic integrated circuits and 64 dual-polarised antennas that allow it to be deployed in dense areas and indoors. Ericsson and IBM also announced their successful demonstration of simultaneous dual polarisation to receive and transmit signals, which enables one of its phased array antenna modules to form two beams concurrently, thereby supporting double the end users.

 

While antennas at 28GHz are tiny, the combination of multiple antennas increases the range of connectivity as well as enabling beam-steering, the companies said. Ericsson and IBM’s device allows for a beamsteering resolution of less than 1.4 degrees.

 

Researchers Develop Energy Efficient Switches for 5G and Terahertz Communication Systems

An RF switch or microwave switch is a device to route high frequency signals through transmission paths. Smartphones are loaded with switches that perform a number of duties. One major task is jumping between networks and spectrum frequencies: 4G, Wi-Fi, LTE, Bluetooth, etc. The current radio-frequency (RF) switches that perform this task are always running, consuming precious processing power and battery life. The switch that the researchers have developed is more than 50 times more energy efficient compared to what is used today. It can transmit an HDTV stream at a 100 gigahertz frequency, and that is unheard of in broadband switch technology. This is the first switch that can function across the spectrum from the low-end gigahertz (GHz) frequencies to high-end terahertz (THz) frequencies that could someday be key to the development of 6G

 

The UT team’s switches use the nanomaterial hexagonal boron nitrite (hBN). It is an emerging nanomaterial from the same family as graphene, the so-called wonder material. The structure of the switch involves a single layer of boron and nitrogen atoms in a honeycomb pattern, which is said to be almost 1 million times thinner than human hair, sandwiched between a pair of gold electrodes. This research spun out of a previous project that created the thinnest memory device ever produced using hBN. The sponsors encouraged the researchers to find other uses for the material and that led them to pivot to RF switches .

 

Radio-frequency switches are pervasive in military communication, connectivity and radar systems. These new switches could provide large performance advantage compared to existing components and can enable longer battery life for mobile communication and advanced reconfigurable systems. The impact of these switches extends beyond smartphones. Satellite systems, smart radios, reconfigurable communications, the internet of things and defense technology are all examples of other potential uses for the switches.

 

The research was funded through grants from the U.S. Office of Naval Research, the Army Research Office, and an Engineering Research Center funded by the National Science Foundation. Fabrication of the switch was partly done at the Texas Nanofabrication Facility, and hBN samples were provided by Grolltex Inc.

 

5G RF filters

Top tier 4G/LTE mobile devices contain between 50 and 90 RF filters to support usage in countries across the world. These filters let desired RF signals pass while blocking adjacent unwanted signals that can interfere with the signal. A new filter is needed for every antenna and frequency band supported by the device. Thus, the addition of 5G frequencies and support of antenna diversity will drive the increase in filters in next-generation mobile devices, automobiles and other wireless connected systems.

 

The transition to 4G required new RF filter resonator structures — film bulk acoustic resonator (FBAR) and solidly mounted resonator, bulk acoustic wave (SMR-BAW) resonating structures were developed to accommodate the increases in frequency to around 2 GHz and in bandwidth to 70 MHz. Similar innovation is needed for 5G as these networks operate in higher frequency bands, requiring new underlying resonator structures to drive performance standards for RF filters. 5G envisions dramatic performance improvements in network capacity, mobile connections, latency, cost, data rates and coverage.

 

Resonant’s XBAR is a new bulk acoustic wave (BAW) structure that can be produced in silicon using standard processes. Simulated utilizing the company’s ISN platform, we believe XBAR outperforms best-in-class film bulk acoustic resonator (FBAR) devices in frequencies above 3 GHz. 5G wireless services for mobile devices are expected to operate in this higher frequency range to support high-bandwidth data applications. Today’s filter technologies (surface acoustic wave (SAW), temperature compensated SAW (TC-SAW), BAW and FBAR) have operating limitations at frequencies higher than 3 GHz. 5G technology holds the promise of brand new consumer and business services, but the requirements for filters to support high frequency, high power and high bandwidth are quite different from those of 4G.

Key performance metrics demonstrated in initial XBAR resonators:

Extremely large coupling coefficients, greater than 500 MHz at 5 GHz (Essential for the design of large bandwidth 5G filters )
High Q resonances, greater than 500, as high as 31 GHz

If successful, XBAR should provide for filter designs for 5G bands with better insertion loss, better rejection levels, higher power handling and wider passbands than currently available filters.

 

Acoustic filter technology

Acoustic filters are the most popular filter technology for mobile devices because of their small size and high performance. They use the piezoelectric effect to convert RF signals into electrical energy. The substrate is finely tuned to produce specific and minute fluctuations. These fluctuations determine which frequencies the filter will process. Filters can select designated signals from specific frequency bands while rejecting unwanted signals that cause interference. Key acoustic filter technologies include Surface Acoustic Wave (SAW) and Bulk Acoustic Wave (BAW) filters where the acoustic energy propagates either on the surface or the bulk of the piezoelectric respectively

 

 

GaN power semiconductors target 5G applications

GaN power semiconductors will play a key role in 5G RF solutions, thanks to their higher efficiency and high-frequency performance. High-performance power semiconductors such as GaN and SiC are playing a key role in 5G radio-frequency (RF) solutions, wireless power transfer (WPT), and base-station power supplies.

5G base stations need to transmit signals in low, medium, and mmWave bands. As frequencies increase, so does the power required to transmit over useful distances. Because of its high-frequency characteristics, GaN offers advantages over other processes for use in 5G base-station power amplifiers (PAs).

 

 

 

References and Resources also include:

http://ieeexplore.ieee.org/document/7839836/

http://www.zdnet.com/article/ericsson-and-ibm-announce-5g-breakthrough/

https://www.fiercewireless.com/wireless/sk-telecom-to-offer-10x-faster-processing-breakthrough-for-5g-standardization

http://dot.gov.in/sites/default/files/5G%20Steering%20Committee%20report%20v%2026.pdf

https://www.eurekalert.org/pub_releases/2019-11/uarl-apm112119.php

https://www.everythingrf.com/News/details/10275-Researchers-Develop-Energy-Efficient-Switches-for-5G-and-Terahertz-Communication-Systems

https://www.ookla.com/articles/state-of-worldwide-5g-2021

https://www.pcmag.com/news/what-is-5g

https://www.viavisolutions.com/en-us/5g-architecture

About Rajesh Uppal

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