ECE 645: WIRELESS NETWORKS
PRESENTATION REPORT
(mmWAVES IN 5G NETWORKS)
Nithin Bidare Puttaraju(31410984)
Santosh Pishey Ramesh()
CONTENTS
ABSTRACT ………………………………………………………………………………….3
1. INTRODUCTION ……………………………………………………………………………4
1.1. EVOLUTION OF 5G ……………………………………………………………5
1.2. 5G USE CASES …………………………………………………………………6
2. 5G mmWAVES ……………………………………………………………………………..8
2.1. Advantages of mmWaves for 5G networks ……………………………….8
3. SPECTRUM ANALYSIS ……………………………………………………………………9
4. mmWAVES Mobile Communication for 5G – Beam Width Interference Resistance and Security .………………………………………………………………10
4.1. Beam width Interference Resistance ……………………………………..11
4.2. Security ………………………………………………………………………..11
5. ANTENNA ARRAY ……………………………………………………………………….12
6. LIMITATIONS OF mmWAVES ………………………………………………………….13
7. BANDWIDTH OF mmWAVES …………………………………………………………..14
8. COMMUNICATION STANDARDS FOR mmWAVES …………………………………15
9. ARCHITECTURE ………………………………………………………………………….16
10. IMPLEMENTATION ………………………………………………………………………17
11. CONCLUSION AND FUTURE SCOPE …………………………………………………21
12. REFERENCES …………………………………………………………………………….22
Abstract
In the near future, i.e., beyond 4G, some of the prime objectives or demands that need to be addressed are increased capacity, improved data rate, decreased latency, and better quality of service. To meet these demands, drastic improvements need to be made in cellular network architecture.
The massive amounts of bandwidth available at millimeter-wave frequencies (above 10 GHz) have the potential to greatly increase the capacity of fifth generation cellular wireless systems. The mmWave bands offer orders of magnitude greater spectrum than current cellular allocations and enable very high-dimensional antenna arrays for further gains via beamforming and spatial multiplexing. However, due to the unique nature of propagation in these bands, cellular systems will need to be significantly redesigned to overcome the high isotropic propagation loss experienced at these frequencies, at both the base station and the mobile terminal to achieve sufficient link budget in wide area networks. This reliance on directionality has important implications for control layer procedures. We will look into the advantages and limitations of mmWaves. Also, we depict the Spectrum analysis in mmWave based systems. This report also provides an example of the architecture of 5G networks which use mmWaves along with implementation.
1. Introduction
The present cell phones have it all. Today phones have everything ranging from the smallest size, largest phone memory, speed dialling, video and audio players, camera and so on. Recently with developments of piconets and Bluetooth technology data sharing has become a child's play. Earlier you can share a data using infrared by keeping two devices in line of sight then by Bluetooth you can transfer a data even when you have cell phone in your pocket up to range of 50 meters. The creation and entry of 5G technology into a mobile marketplace will launch a new revolution in the way international cellular phones and plans are offered.
Regarding the 4G, its focus is towards seamless integration of cellular networks such as GSM and 3G. Multimode user terminals are seen as must have for 4G, but different security mechanisms and different QoS support in different wireless technologies remain a challenge. However, integration among different wireless networks is functioning in practice even today. Just around the corner, the newest 5G technologies will hit the mobile market with phones used in China being able to access and call locally phones in Germany. Truly innovative technology changing the way mobile phones will be used. With the emergency of the cell phones, which are similar to a PDA, you can now have your whole office within the phone. Even today there are phones with gigabytes of memory storage and the latest operating systems. Thus, one can say that with the current trends. The industry has a real bright future if it can handle the best technologies and can produce affordable handsets for its customers.
5G Network's router and switch technology delivers Last Yard Connectivity between the Internet access provider and building occupants. 5G's technology intelligently distributes Internet access to individual nodes within building.
The primary technologies of 5G wireless networks include Millimeter wave bands, Massive MIMO, Low-Band 5G and Mid-band 5G. Millimeter wave bands offer performance as high as 20 gigabits per second. The millimeter wave systems are designed for 20 gbps peak downloads. Their estimated median bandwidth is 3.5 gbps. The estimated median bandwidth for the band of 3.5 GHz-4.2 GHz with additional MIMO antennas is 490 megabits per second. In mid-band frequencies, the modelled 5G speed is very similar to the 4G LTE speed, assuming the same bandwidth and antenna configuration.
1.1. Evolution of 5G
The industry now refers to as generations of technology. In reality, generations are always based on groups of standards, which may be deployed for a period of time. It is very likely to continue with 5G, so there will be no single point where 5G is deployed, rather it will be deployed in stages as the capability is defined and developed. Below is the summary of the mobile generations:
" 1G: Analogue technology from the 1980s – no longer used.
" 2G: Digital systems from the 1990s, mostly using Global System Mobile (GSM). Data rate up to 9.6kbps per channel.
" 2.5G: GSM Extension with Enhanced Data GSM Evolution (EDGE) and General Packet Radio Service (GPRS) – the first virtual data network using the Wireless Application Protocol (WAP) and delivering up to 144kbps, or 384kbps with EDGE.
" 3G: Introduces High Speed Packet Access (HSPA), a true IP‐based Internet access at higher data rates. Rates of 3Mbps became possible, rising to a theoretical 14Mbps (real life average 3Mbps) with the 3.5G technology, high speed packet access (HSPA).
" 4G: Introduces LTE, initially defined in 3GPP Release 8 in 2008, which enables an end‐to‐ end IP network to be deployed. Now widely deployed in the UK, 4G can deliver true broadband speeds of up to 100Mbps, with 10 to 20Mbps being typical in urban areas.
" 5G: Introduces heterogeneous radio interfaces, improved antenna design, and more frequency bands. The definition started in version 11 in 2012 and will last until the last announcement of release 15
Things are moving at the speed of blisters in the next generation of 5G mobile communications world, although many mobile users have yet or only recently upgraded to 4G LTE communications, and even as 4G continues to develop.
5th generation mobile networks or 5th generation wireless systems, abbreviated 5G, are the proposed next telecommunications standards beyond the current 4G/IMT-Advanced standards, operating in the millimetre bands (28, 38, and 60 GHz).
5G planning aims at higher capacity than current 4G, allowing a higher density of mobile broadband users, and supporting device-to-device, more reliable, and massive machine communications. 5G research and development also aims at lower latency than 4G equipment and lower battery consumption, for better implementation of the Internet of things. There is currently no standard for 5G deployments.
1.2. 5G Use Cases
Fig1: 5G use cases
The Next Generation Mobile Networks defines the following requirements that a 5G standard should fulfil.
" Data rates of tens of megabits per second for tens of thousands of users
" Data rates of 100 megabits per second for metropolitan areas
" 1 Gb per second simultaneously to many workers on the same office floor
" Several hundreds of thousands of simultaneous connections for wireless sensors
" Spectral efficiency significantly enhanced compared to 4G
" Coverage improved
" Signalling efficiency enhanced
" Latency reduced significantly compared to LTE.
In addition to providing simply faster speeds, they predict that 5G networks also will need to meet new use cases, such as the Internet of Things (internet connected devices), as well as broadcast-like services and lifeline communication in times of natural disaster. Carriers, chipmakers, OEMS and OSATs, such as Advanced Semiconductor Engineering (ASE) and Amkor Technology, Inc., have been preparing for this next-generation (5G) wireless standard, as mobile systems and base stations will require new and faster application processors, basebands and RF devices.
Although updated standards that define capabilities beyond those defined in the current 4G standards are under consideration, those new capabilities have been grouped under the current ITU-T 4G standards. The U.S. Federal Communications Commission (FCC) approved the spectrum for 5G, including the 28 GHz, 37 GHz and 39 GHz bands, on 14 July 2016.
2. 5G mmWaves
Fig 2: mmWaves Spectrum
Millimeter wave spectrum is the band of spectrum between 30 GHz and 300 GHz. Wedged between microwave and infrared waves, this spectrum can be used for high-speed wireless communications as seen with the latest 802.11ad Wi-Fi standard (operating at 60 GHz). It is being considered by standards organization, the Federal Communications Commission and researchers as the way to bring "5G" into the future by allocating more bandwidth to deliver faster, higher-quality video, and multimedia content and services. It has two characteristics because wave is located in the overlapping wavelength range of microwave and far of infrared wave.
2.1. Advantages of mmWaves for 5G networks
mmWaves have greater frequency allocation along with highly directional beam forming antennas. They have the best QoS (Quality of Service). But, above 24 GHz, everything gets more difficult. Like, semiconductor process capabilities decline, design difficulty increases, propagation losses increase and non-line-of-sight communications becomes a real challenge and system designs to address the above become more challenging. Yet, we choose to use mmWave frequencies because the best way to achieve the peak data rates of up to 10Gbps and wider channel bandwidths to increase the channel capacity.
mmWaves have high data rates, gives improved battery life, are more reliable, have high level of security and are highly efficient.
3. SPECTRUM ANALYSIS
Shannon's Theorem gives an upper bound to the capacity of a link, in bits per second (bps), as a function of the available bandwidth and the signal-to-noise ratio of the link. The Shannon Theory tells the maximum rate at which information can be transmitted over a specified bandwidth channel in the presence of noise.
The Theorem can be stated as:
C = B * log2(1+ S/N)
where C is the achievable channel capacity, B is the bandwidth of the line, S is the average signal power and N is the average noise power.
The signal-to-noise ratio (S/N) is usually expressed in decibels (dB) given by the formula:
10 * log10(S/N)
So for example a signal-to-noise ratio of 1000 is commonly expressed as
10 * log10(1000) = 30 dB.
Here is a graph showing the relationship between C/B and S/N (in dB):
Fig: graph showing the relationship between C/B and S/N (in dB)
4. mmWave Mobile Communication for 5G – Beam Width Interference Resistance And Security
The main benefit that millimeter Wave technology has over RF frequencies is the spectral bandwidth of 5GHz being available in these ranges, resulting in current speeds of 1.25Gbps Full Duplex with potential throughput speeds of up to 10Gbps Full Duplex being made possible. Service providers can significantly expand channel band width way beyond 20 MHz Once market demand increases and better modulation techniques are implemented, spectral efficiency of the equipment will improve allowing the equipment to meet the higher capacity demands of prospective future networks.
4.1. Beam Width Interference Resistance
Millimeter wave signals transmit in very narrow focused beams which allows for multiple deployments in close range using the same frequency ranges. This allows Millimeter wave ideal for Point-to-Point Mesh, Ring and dense Hub & Spoke network topologies where lower frequency signals would not be able to cope before cross signal interference would become a significant limiting factor. The beam width is approx. 2 degree this benefit from increased interference protection and spectrum reuse. The highly directional and narrow radiation pattern from millimeter wave allows many transmitters to be deployed near each other without causing troublesome interference even when they are using the same frequencies. Using cross-polarization techniques allows even more radios to be deployed in an area, even along the 16 same path.
4.2. Security
Since millimeter waves have a narrow beam width and are blocked by many solid structures they also create an inherent level of security. In order to sniff millimeter wave radiation a receiver would have to be setup very near, or in the path of, the radio connection. The loss of data integrity caused by a sniffing antenna provides a detection mechanism for networks under attack. Additional measures, such as cryptographic algorithms can be used that allow a network to be fully protected against attack.
Fig 3: 4.2.0 milimeter wave beam width
5. ANTENNA ARRAY
Due to the recent advancements in VLSI technology it is possible to develop circuits that work in millimeter wave frequency range. The choice of integrated circuit (IC) technology depends on the implementation aspects and system requirements. The former is related to the issues such as power consumption, efficiency, dynamic range, linearity requirements, integration level, and so forth, while the later is related to the transmission rate, cost and size, modulation scheme, transmit power, bandwidth, and so forth.
At millimeter wave, there are three competing IC technologies, namely: (1) Group III and IV semiconductor technology such as Gallium Arsenide (GaAs) And Indium Phosphide (InP) (2) Silicon Germanium (SiGe) technology such as HBT and BiCMOS (3) Silicon technology such as CMOS and BiCMOS. There is no single technology that can simultaneously meet all the objectives defined in the technical challenges and system requirements.
For example, GaAs technology allows fast, high gain, and low noise implementation but suffers poor integration and expensive implementation. On the other hand, SiGe technology is a cheaper alternative to the GaAs with comparable performance. In the first millimeter wave fully antenna integrated SiGe chip has been demonstrated.
Typically, as have been witnessed in the past, for broad market exploitation and mass deployment, the size and cost are the key factors that drive to the success of a particular technology. In this regard, CMOS technology appears to be the leading candidate as it provides low-cost and high integration solutions compared to the others at the expense of performance degradation such as low gain, linearity constraint, poor noise, lower transit
Fig 4: Antenna Array for highly directional MIMO transmission
6. LIMITATIONS OF MILLIMETER WAVES
In order to implement the systems which are to accommodate millimetre waves, we need to study the limitations and thus, build our system around these limitations. The major limitations of mmWaves are that
1. mmWaves cannot propagate over long distances. There is a path loss due to oxygen absorption and water absorption. The blue circles in the below graph of sea level attenuation versus the frequency (GHz) represents the oxygen absorption and the green circles represent the water absorption.
Fig 5: Attenuation by oxygen absorption and water absorption
2. mmWaves cannot pass through obstacles like concrete walls etc., so we need to have a line of sight from the transmitter to the receiver. We need to build our transmitters which are of a few 10s or 100s of meters around the receivers such that the line of sight communication is made possible.
Fig 6: Figure showing mmWaves being blocked off by hard surfaces
3. Implementation of beam forming and beam steering antennas are complex and expensive. Beam forming and beam steering antennas use complex algorithms to find the exact location of the receiver so that all of the transmitted power is directed towards a specific point.
7. BANDWIDTH OF MILLIMETER WAVES
Extremely high speeds in 5G requires extremely high frequency and a high bandwidth. Millimeter wave spectrum is the band of spectrum between 30 GHz and 300 GHz. Millimeter waves is placed between microwave and infrared waves, and this spectrum can be used for high-speed wireless communications as seen with the latest 802.11ad Wi-Fi standard (operating at 60 GHz). It is being considered by standards organization, the Federal Communications Commission and researchers as the way to bring "5G" into the future by allocating more bandwidth to deliver faster, higher-quality video, and multimedia content and services.
High frequency means narrow wavelengths, and for mm waves that sits in the range of 1 millimeter to 10 millimeters. Its strength can be reduced due to vulnerabilities against gases, rain and humidity absorption. Due to those factors millimeter, wavelengths only reach out to a few kilometers.
8. COMMUNICATION STANDARDS FOR MILLIMETER WAVES
IEEE 802.11 ad (WiGig or Wireless Gigabit):
The IEEE 802.11ad standard aims to provide data throughput speeds of up to 7 Gbps. To achieve these speeds, the technology uses the 60 GHz ISM band to achieve the levels of bandwidth needed and ensure reduced interference levels.
Using frequencies in the millimeter range IEEE 802.11ad microwave Wi-Fi has a range that is measured of a few meters. The aim is that it will be used for very short range (across a room) high volume data transfers such as HD video transfers. When longer ranges are needed standards such as 802.11ac can be used. As part of the marketing, the scheme will be known by the name WiGig after the Wireless Gigabit Alliance that endorses the system.
In order to provide support to the industry and an easy marketing name, the IEEE and Wireless Gigabit Alliance have worked together on developing the IEEE 802.11ad WiGig standard. The WiGig MAC/PHY specification aligns exactly with the 802.11ad standard. This provides industry standardization, industry recognition, input from industry to ensure that the standard is realizable and also meets the industry needs, and it also provides an easy marketing name.
IEEE 802.11 ay
"Enhanced Throughput for Operation in License-Exempt Bands above 45 GHz".
IEEE 802.11 ay is expected to develop an amendment that defines standardized modifications to both the IEEE 802.11 physical layers (PHY) and the IEEE 802,11 medium access control layer (MAC) that enables at least one mode of operation capable of supporting a maximum throughput of at least 20 gigabits per second (measured at the MAC data service access point), while maintaining or improving the power efficiency per station. This amendment also defines operations for license-exempt bands above 45 GHz while ensuring backward compatibility and coexistence with legacy directional multi-gigabit stations (defined by IEEE 802.11ad-2012 amendment) operating in the same band.
9. ARCHITECTURE
Fig 7: General 5G architecture
Architecture of 5G is highly advanced, its network elements and various terminals are characteristically upgraded to afford a new situation. Likewise, service providers can implement the advance technology to adopt the value-added services easily. The general architecture of 5G is shown in the figure above. The main focus for millimeter wave implementation is in the small cells where the communication is line-of-sight.
However, upgradeability is based upon cognitive radio technology that includes various significant features such as ability of devices to identify their geographical location as well as weather, temperature, etc. Cognitive radio technology acts as a transceiver (beam) that perceptively can catch and respond radio signals in its operating environment. Further, it promptly distinguishes the changes in its environment and hence respond accordingly to provide uninterrupted quality service.
10. IMPLEMENTATION
In order to implement the systems which would use millimeter waves, we need to modify transmitters to include smart beam forming and beam steering antennas with complex algorithms. We also need to introduction of a new access technology – NOMA. We need to modify the receivers such that they are capable of performing complex algorithms. Mobile millimeter waves need control and data channel support for adaptive beamforming and beam-tracking techniques to enable use of high-band mmWave spectrum that deliver extreme data rates and capacity in a mobile environment.
1. Use beam forming and beam steering antennas
Beamforming is a type of Radio Frequency management in which an access point uses multiple antennas (or antenna array) to send out the same signal we need the same beam shape at the transmitter side and the receiver side, so we need antennas that are capable of beam forming. The below figure shows an instance of beam forming.
Fig 8: Figure showing antenna beam forming
Beam steering refers to changing the direction of the main lobe of the beams formed towards a particular direction based on algorithms. This can be done by changing the phases of the RF signals driving the elements. Steering the beams in a particular direction supports line of sight communication and there is no loss of power as the beams are focused towards one direction. The below figure illustrates how the beam steering is done in the antennas.
Fig 9: Figure showing antenna beam steering
2. New Access Technology – NOMA (Non-Orthogonal Multiple Access)
Non-orthogonal multiple access is having signals that possess significant differences in power levels. In NOMA, we totally isolate the high level signal at the receiver and then cancel it out to leave only the low level signal. In this way, NOMA exploits the path loss differences amongst users, although it does need additional processing power in the receiver.
Non-orthogonal multiple access (NOMA) is an essential enabling technology for the fifth-generation (5G) wireless networks to meet the heterogeneous demands on low latency, high reliability, massive connectivity, improved fairness, and high throughput. The key idea behind NOMA is to serve multiple users in the same resource block, such as a time slot, subcarrier, or spreading code. The NOMA principle is a general framework, and several recently proposed 5G multiple access schemes can be viewed as special cases. This can also be extended to 5G networks that are designed to accommodate millimeter waves.
The system model we used in this consideration is shown in the following image:
Fig 10: NOMA system model
Here we have a tiered model where the macro cell BS distributes resources to Macro Cell Users, Pico BSs and Femto BSs based on power level. Pico/Femto BS divides the allocated resources to Small Cell Users. The resource allocation is done based on power levels, using the NOMA method. At the small cells, we have a line of sight communication.
Successive Interference Cancellation (SIC)
Successive interference cancellation (SIC) is a well-known physical layer technique. SIC is, basically, the ability of a receiver to receive two or more signals concurrently (that otherwise cause a collision in today's systems). SIC is possible because the receiver may be able to decode the stronger signal, subtract it from the combined signal, and extract the weaker one from the residue. This technique needs to be implemented at the receiver side of systems implementing the NOMA method of access.
11. CONCLUSION AND FUTURE SCOPE
This project provides a study of millimeter waves used in future 5G wireless networks. As we have already seen, using the millimeter wave region for communication saves a lot of bandwidth and supports high data speeds. 5G mmWave wireless channel bandwidths will be more than ten times greater than today's 4G Long-Term Evolution (LTE) 20 MHz cellular channels. Since the wavelengths shrink by an order of magnitude at mmWave when compared to today's 4G microwave frequencies, diffraction and material penetration will incur far more attenuation, thus elevating the importance of line-of-sight (LOS) propagation, reflection, and scattering. Accurate propagation models are vital for the design of new mmWave signaling protocols (e.g., air interfaces). Over the past few years, measurements and models for a vast array of scenarios have been presented by many companies and research groups. Millimeter waves can be extended to be implemented in future cities, that can be built with millions of smart devices occupying its own bandwidth and interconnected using the Internet of Things.
12. REFERENCES
" http://www.radio-electronics.com/info/wireless/wi-fi/ieee-802-11ad-microwave.php
" http://www.ieee802.org/11/Reports/tgay_update.htm
" https://www.rcrwireless.com/20160815/fundamentals/mmwave-5g-tag31-tag99
" https://spectrum.ieee.org/video/telecom/wireless/5g-bytes-beamforming-explained
" https://spectrum.ieee.org/tech-talk/telecom/wireless/a-beam-steering-antenna-for-real-world-mobile-phones
" http://www.radio-electronics.com/info/rf-technology-design/noma-non-orthogonal-multiple-access/basics-tutorial.php
" https://arxiv.org/abs/1706.05347
" https://ieeexplore.ieee.org/document/7973146/
" http://synrg.csl.illinois.edu/papers/sic-camera.pdf
" https://ieeexplore.ieee.org/document/7999294/