Energy Efficiency Maximisation in Large-Scale MIMO Systems

Energy Efficiency Maximisation in Large-Scale MIMO Systems Analysis of Energy Efficiency Maximisation in Large-Scale MIMO Systems Introduction and Motivation 1.1 Background The development of smart terminals and their application, the need for multimedia services rapidly increases lately [1]. The capacity of wireless the Quality of Service necessities of mobile applications of wireless communication networks is increasing exponentially [1]. Bandwidth Efficiency is typically one of the important metrics to Systems [1], [1]. Energy Efficiency become a metric for assessing the performances of wireless communications systems with some BE restrictions [1] [1]. 1.2 Research Motivations An accurate modelling of the total power consumption is the primary of (BS) antennas and number of active (UEs) for LS-MIMO systems [15]. 1.3 Research Aim and Objectives The research objectives which are briefly explained and summarized as below: To compare the performance of the proposed uplink and downlink of LS-MIMO systems for ZF, MRT/MRC, and MMSE processing schemes at BS. To implement a new refined model of the total power consumption for LS-MIMO system. To derive closed-form EE-maximal values of number of (BS) antennas, number of active (UEs), and the transmit power using ZF processing in single-cell system and new refined model of the total power consumption when the other two are fixed. To evaluate analytic results for ZF processing scheme with perfect CSI. To measure numerical results for ZF, MRT/MRC, and MMSE processing schemes processing schemes with perfect CSI in a single-cell scenario. To measure numerical results for ZR processing schemes with imperfect CSI, and in a multi-cell scenario. 1.4 Main Contributions This thesis has contributions to knowledge in three research issues for LS-MIMO system, which are the new refined circuit power consumption model, energy efficiency maximisation with ZF processing scheme, and deployment of imperfect CSI case and symmetric multi-cell scenario. Those main contributions of this thesis are summarized and elaborated more detail as follows: The circuit power consumption is the sum of the power consumed by different analogue components and digital signal processing. The new refined model of the total power explicitly described how the total power consumption depends non-linearly on number of number of UEs, number of BS antennas, and transmit power. The closed-form EE expression under the assumption of ZF processing scheme is employed in the uplink and downlink for optimal number of UEs, number of BS antennas, and transmit power for a single-cell scenario with perfect CSI. This option is driven by analytic convenience and numerical results likewise which are close to optimal. Analysis of imperfect CSI case and symmetric multi-cell scenarios deployment are extended using the same method above. A New achievable rate derived for symmetric multi-cell scenarios with ZF processing. 1.5 Research Methodology In the first stage of the research, literature review of past and current works on the area of MIMO, MU-MIMO, and LS-MIMO are extensively conducted to broaden the perspective on such areas of study. Furthermore, state of the art related to those addressed issues are deeply studied and intensively explored during this period. Following the literature review phase, implementation starts with formulating the EE maximisation problem. A new refined circuit power consumption model is proposed. All this then used to compute closed-form expression for the optimal number of UEs, number of BS antennas, and transmit power under the assumption of ZF processing scheme. The testing stage starts with simulation. All the simulations were performed using Monte Carlo Simulation techniques in Matlab. Monte Carlo simulation can handle very complex and realistic. Monte Carlo Simulation were executed for all the investigated schemes with perfect CSI, for ZF with imperfect CSI, and in a multi-cell scenario In the validation stage, numerical results are used to authenticate the theoretical analysis and make comparison amongst different processing schemes. 1.6 Thesis Structure This thesis comprises of six chapters, where each chapter is inter- dependent. Chapter 1 Introduction: Chapter 2 LS-MIMO-An overview: This chapter presents an overview of the LS-MIMO concept. Chapter 3 Literature Review- Energy Efficiency Maximisation in LS-MIMO: Chapter 4 Techniques to Maximise Energy Efficiency: The simulation procedures will be explained in this chapter. Chapter 5 Result and Analysis: This chapter describes description and evaluation for this investigation of LS-MIMO . Chapter 6 Conclusion Further Work: This chapter concludes the results of the implementations, and recommendation of developing revised model for LS-MIMO systems. LS-MIMO An Overview 2.1 Introduction to LS-MIMO Wireless communication is one of the most successful technologies is one of the most successful technologies in modern years, given that an exponential growth rate in wireless traffic (known as Coopers law) [1]. This trend will certainly drive by; for example, augmented reality and internet-of-things [1]. Figure 2-1:[6] 2.2 Antenna configurations Radio-Frequency (RF) circuit is usually connected to its physical antennas through an RF cable in a passive AA. A Remote Radio Unit (RRU) in with a Baseband Unit (BBU) has become a preferred configuration recently [1]. 2.3 Channel Measurements Realistic channel measurements have been carried out in in an effort to identify the main characteristics of LS-MIMO channels [15] 2.4 Channel Model Three types of channel models have been used for evaluating the performance of wireless communications systems, namely the Correlation-Based Stochastic Model (CBSM), the Parametric Stochastic Model (PSM) and the Geometry- Based Stochastic Model (GBSM) in [1]. 2.5 Processing Schemes Precoding LS-MIMO is based on linear processing at the BS. BS has observation of the multiple access channels from the terminals [6]. The BS applies linear receive combining to discriminate the signal transmitted [6]. The simplest choice is maximum ratio (MR) combining by adding the signal components coherently. In [6], this result signal amplification proportional to. Energy Efficiency Problem Literature Review 3.1 System and Signal Model The uplink and downlink of a single-cell multiuser MIMO system operating is considered over a bandwidth of B Hz [15]. 3.2 Channel Model and Linear Processing The M antennas at the BS are spaced apart such that the channel components between the BS antennas and the single-antenna UEs are uncorrelated [15]. The channel describes propagation channel between antenna at the BS and the UE. We assume small scale fading distribution [15]. 3.3 Uplink In [15], under the assumption of Gaussian, linear processing, and the perfect CSI, the achievable uplink rate of the th UE is (3.6) the pre-log factor accounts for pilot overhead and is the fraction of uplink transmission [15]. In addition, (3.7) 3.4 Downlink A normalized precoding vector and the downlink signal to the kth is assigned a transmit power of . In [15], assuming Gaussian codebooks and perfect CSI the achievable downlink rate of the kth UE with linear processing is (3.13) 3.5 Problem Statement The EE of a communication system is measured in bit/Joule and the average total power consumption (in Watt = Joule/second) [15]. The total EE of the uplink and downlink is (3.20) Energy Efficiency Maximisation-Techniques 4.1 Realistic Circuit Power Consumption Model The sum of the power consumed by different components and signal processing is the circuit consumption is [15]. A power consumption model is proposed (3.22) 4.2 Energy Efficiency Maximisation with ZF Processing The EE maximisation problem is resolved under the assumption that ZF processing is employed. This solution is driven by analytic and the numerical results [15]. For ZF processing, Problem 1 reduces to (3.30) 4.3 Extension to Imperfect CSI and Multi-Cell The analysis is prolonged to single-cell scenarios with imperfect CSI. A new achievable rate is derived with ZF forcing processing. The achievable user rates in single-cell scenarios with imperfect CSI [15]. (3.52) Simulation Setup and Numerical Results 5.1 Simulation Setup Simulations used to validate the system design guidelines under ZF processing and to make comparison with other processing schemes [15]. Numerical results provided under both perfect and imperfect CSI, and for single-cell and multi-cell scenarios [ 15]. For stimulating ZF, and MRT analytic results were executed and MMSE, and Monte Carlo simulations were performed to maximise EE [15]. 5.2 Single-Cell Scenario The chosen deployment model validated. 5.3 Multi-Cell Scenario A lot of studies have been carried out. Conclusions and Future Research 6.1 Conclusions This thesis focuses on the energy maximisation improvement of the LS-MIMO systems to cope with energy maximisation problem. The thesis has three main contributions; all are elaborated in detail. 6.2 Future Research Several recommendations, which may guide to the future research directions on LS-MIMO systems. Bibliography [1] K. Zheng, L. Zhao, J. Mei, B. Shao, W. Xiang and L. Hanzo, Survey of  Large- Scale MIMO Systems, in IEEE Communications Surveys   Tutorials, vol.17, no. 3, pp. 1738-1760, third quarter 2015. [2] D. Feng et al., A survey of energy-efficient wireless communications, IEEE Commun. Surveys Tuts., vol. 15, no. 1, pp. 167-168, 1st Quart. 2012. [3] T. Kailath and A. J. Paulraj, Increasing capacity in wireless broadcast   systems using Distributed Transmission/Directional Reception (DTDR), U.S. Patent 5 345 599, Sep. 6, 1994. [4] E. G. Larsson, F. Tufvesson, O. Edfors, and T. L. Marzetta, Massive MIMO for next generation wireless systems, IEEE Commun. Mag., vol. 52, no. 2, pp. 186-195, Feb. 2014. [5] Views on Rel-12 and Onwards for LTE and UMTS, 3GPP RWS-120006, HUAWEI and HiSilicon, 2013. [6] E. Bjà ¶rnson, E. G. Larsson and T. L. Marzetta, Massive MIMO: ten myths  and One critical question, in IEEE Communications Magazine, vol. 54,  no. 2, pp.114-123, February 2016. [7] S. Tombaz, A. Và ¤stberg, and J. Zander, Energy- and cost-efficient ultra- high-capacity wireless access, IEEE Wireless Commun. Mag., vol. 18, no. 5, pp. 18-24, Oct. 2011. [8] E. Bjà ¶rnson, M. Kountouris, and M. Debbah, Massive MIMO and small  cells: Improving energy efficiency by optimal soft-cell coordination, in  Proc. ICT, 2013, pp. 1-5. [9] E. Bjà ¶rnson and E. Jorswieck, Optimal resource allocation in  Coordinated multi-cell systems, Found. Trends Commun. Inf. Theory,  vol. 9, no. 2/3, pp. 113-381, 2013. [10] Y. Wu, R. Zhou, and W. Zhang, Active antenna system: Utilizing the full  potential of radio sources in the spatial domain, Huawei, Shenzhen,  China, 2012. [11] S. Payami and F. Tufvesson, Channel measurements and analysis for very large array systems at 2.6 GHz, in Proc. 6th EUCAP, Prague, Czech Republic, Mar. 2012, pp. 433-437. [12] Further Advancements for E-UTRA Physical Layer Aspects (Release   9),3GPP TS 36.814, Mar. 2010. [13] H. Boche and M. Schubert, A general duality theory for uplink and  downlink beamforming, in Proc. IEEE VTC-Fall, 2002, pp. 87-91. [14] R. Kumar and J. Gurugubelli, How green the LTE technology can be?in  Proc. Wireless VITAE, 2011, pp. 1-5. [15] E. Bjà ¶rnson, L. Sanguinetti, J. Hoydis and M. Debbah, Optimal  Design of Energy-Efficient Multi-User MIMO Systems: Is Massive  MIMO the Answer?, in IEEE Transactions on Wireless  Communications, vol. 14, no. 6, pp. 3059-3075, June 2015.

Having a Dream Becomes Reality Essay

Obstacles always hinder people when they are trying to reach their goals, and those are just ordeals to test their perseverance. In reality, nothing can be obtained or achieved smoothly without going through any difficulties, but once people overcome the obstacles they will achieve the desired goal. In the movie October Sky, directed by Johnston, is about a young man named Homer Hickam who grows up in Coalwood and aspires to become a miner like every male in the town. He becomes obsessed with building his own rockets after he witnesses an artificial satellite goes into orbit, and he achieves a wonderful goal even though he needs to surmount difficulties. However, his passion for building a real rocket makes him willing to take risks and explore new adventures even though he fails several times. There are many kinds of obstacles people face in life, if I had not persuaded myself to keep trying, my dream of going to a better college may not have come true. Indeed, successful people are never giving up their passion to achieve their desired goal even when they are encountering challenges. Accordingly, being adventurous, persistent, and never giving up can be the key characteristics needed for making a dream come true. Adventurous people look for solutions to seek out the answers to the problems they do not understand. Most adventures have elements of uncertainty and fear surrounding them; fear about an uncertain outcome can be a huge deterrent to do adventurous activities. Adventurous people have a mindset that teaches them to seek out new events or activities that can be scary since they do not know what is going to happen, but that is where people need to go. People challenge the difficulties, which is how they can get experience and surmount the obstacles. The main character from the movie, Homer Hickam likes to take risks and challenges himself by building a real rocket after he witnesses the Soviet Union successfully launch the first artificial satellite into orbit. Homer has never touched a welding machine and has no idea how to build a rocket due to limited experience and no professional help. His curious mind makes him studies the instruction books about building rockets. Homer tries so many times to rebuild the rockets due to the failure of launching. There is one time he even blows up his mother’s garden fence, and fortunately no one gets injured. Moreover, when he and his friends test out their rocket at a wasteland, the rocket almost kills his neighbor, Leon Bolden. Even though Homer does not earn his father’s support, and launching is dangerous, he still likes to take risks and continues building rockets. Homer’s adventurous mind makes him successfully launch his real working rocket into the sky eventually. Nevertheless, having only an adventurous mind is not enough to surmount obstacles; being persistent is another key characteristic overcomes obstacles and makes dreams come true. In fact, persistence is the key to success because perseverance will take people a long way, but being willing to be patient while they achieve their goal will take them even further. Homer never quits his dream even when he is accused of having started a forest fire with a rocket that has gone astray, and despite many launching failures, Homer still continues building his dream rocket. Although Homer does not get his father’s permission to build a rocket in their basement, and his father throws his equipment away and prohibits him from doing such unrealistic activity, Homer never gives up even though his launches fail so many times due to his father’s demands. He finds a wasteland and starts building rockets with his friends hoping to go for a national Science Fair. Moreover, Homer does not give up his dream after his father gets injured in the mine. He takes over his father’s work as a coal miner to support his family, and he quits his jobs immediately after his father recovers from injury. Furthermore, Homer proves that his rocket has not gone astray and started a forest fire by showing people where his rocket has exactly landed. Homer’s continuous trying eventually leads him to win the national Science Fair, and he receives a scholarship to go to college. Consequently, without Homer’s persistent mind that leads him keep trying new methods, his dreams would not have come true. Never giving up is the first way to overcome obstacles. People failing do not mean they cannot accomplish their dreams. Never giving up always gives them a second chance, they fail sometimes but it absolutely does not mean that they fail every time. Never giving up is my motto and is what I keep reminding myself to reach where I want to be. I was born in a small and remote village in China. Technological developments and education were relatively poor in my village. As I grew up, I realized the sense in my parents’ emphasis on my education. I discovered that I was their only hope for a lifestyle change, so I decided to study hard in order to help my family to have a better life. The language barrier was one of the difficulties I met when I immigrated to the US. It cost me a lot especially in my grades since I had an extremely difficult time in communicating with my classmates and my teachers. The effect was so immense that I even thought of quitting school at one time. All this negativity came regardless of my dream and promise. However, it completely changed when my parents came for a visit, which was due to a concerned call about my poor grades. To my amazement and shock, my parents had changed significantly with a lot of gray hair replacing with the black. Their thin bodies reflected on the efforts that they had sacrificed for my stay in school. Ever since that day, I have focused on surmounting any barriers. After a lot of efforts, I finally secured a place in a college with a better reputation. Therefore, without having never giving up mindset I might not have a chance to go a college. No matter what impedes them from reaching a desired goal, successful people face difficulties instead of avoiding them. Obstacles give people a chance to get insight on many new aspects and even change their perspectives on many situations. Surmounting obstacles is an essential step people face in order to make their dreams come true. For instance, if Homer is not willing to take risks and challenging the difficulties, he cannot launch his real working rocket into the sky successfully. Persistence means continuing to work toward a goal even when it takes a long time, without persistent belief that leads Homer keeps trying new methods, his dreams of building a rocket would not have come true. Furthermore, if I did not keep reminding myself of never giving up, I probably cannot secure a place in a better college. All the examples listed above demonstrate that being adventurous, persistent, and never giving up are the key characteristics needed to conquer obstacles and make a dream come true.

BAZAARS OF HYDERABAD Essay

In The Bazaars of Hyderabad is a vibrant, colorful poem describing the bazaars of Hyderabad. This poem was written during the British Rule when Indians were asked to boycott foreign products and buy goods from traditional Indian bazaars. During this time, publication of Indian newspapers was banned so she might have thought the best way to spread the message to people was through her poems. In The Bazaars of Hyderabad begins with a question from the poet to the merchants in the bazaar about what they are selling. The merchants reply that they are selling silver and crimson colored turbans, purple brocade tunics, mirrors framed in amber and daggers with handles made of jade. The first stanza ends there. The next stanza is about another stall and the same question is asked by the poet to the vendors about what they are weighing and selling. Saffron, lentils and rice are being sold by the vendors. The poet asks the maidens what they are grinding and she gets a reply that they are grinding henna, sandalwood and spices. The poet then questions the pedlars about what they are selling and they say chessmen dice made from ivory. The third stanza takes us to a jewelry store where the poet asks the goldsmith what ornaments they make. Wristlets, anklets and rings are made is the reply. Moreover, they say they manufacture bells for blue pigeons to be tied to their feet. The bells are as delicate as a dragonfly’s wing. Simultaneously they make gold girdles for dancers and sheaths for kings to keep their swords. The poet visits a fruit shop in the fourth stanza of the poem In The Bazaars of Hyderabad. There she enquires about what they are selling. They tell her they sell lemon, pomegranate and plum. Then the musicians are asked what they play and they say sitar, sarangi and drums are played. She even comes across magicians and asks them what they are chanting and they say that they are chanting magical spells to charm thousand ages to come. The final stanza is about the flower girls who are asked what they are weaving with strands of red and blue flowers. The girls reply that they making garlands for bride and groom to decorate their bed for their wedding night. They are also weaving sheets of white flowers which are placed on graves for fragrance purposes. In The Bazaars of Hyderabad is lucid and vivid in language. It creates beautifully a colorful picture of the bazaar in the minds of its readers.

Taking a Look at Greek Tragedies - 2583 Words

The word ‘tragedy’ can be traced back to Ancient Greece. Although it now holds a very firm meaning it once was believed to mean â€Å"goat-song† it had a connection to the Greek god Dionysus (â€Å"Tragedy†). Tragedies have evolved throughout the centuries and there is myriads of definitions for tragedies many of which refute the others, however, Aristotle’s Poetics gives its own definition as well as lots of insight. While there is no universal agreement of how a tragedy exactly should be concocted there are many reoccurring themes in tragedies which are present in Antigone such as the law of men against the law of the gods, Hamartia (the tragic flaw), View on Women, the bonds of family and the metaphor used by Aristotle which he values so highly: Catharsis. At the beginning of the play the audience is in ignorance but as the tragedy develops and uses its themes by the end it emanates knowledge. 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