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Wireless communications has become an emerging and fastly growing field in our modern life and creates enormous impact on nearly every feature of our daily life. A tremendous technological transformation during the previous two decades has provided a potential growth in the field of digital communication and lot of latest applications and technologies are coming up every day due to these valid reasons. Digital modulation schemes contribute to the evolution of mobile communications by increasing the capacity, speed as well as the quality of the wireless network. In communication, the concept of modulation is a prime factor because without an appropriate modulation scheme, it would be impossible to achieve an expected throughput. Available bandwidth, permissible power and inherent noise level of the system are the constraints which should be considered while developing the communication systems. Due to error-free capability in digital modulation, it is preferred over the analogue modulation techniques. The Worldwide interoperability for Microwave Access (Wi-max) uses combinations of different modulation schemes which are BPSK, QPSK , 4-QAM AND 16-QAM and it is a promising technology which offers high speed voice, video and data services. In this paper the literature review on the different digital modulation techniques which are generally used for the wireless communication is presented.
For transferring data to increase performance and implementation simplicity different analogue and digital techniques are used in fiber optic communication channel. Different digital modulation formats maximizes spectral efficiency and also improves tolerance to transmission impairments. This paper reviews a comparative analysis for the different digital modulation formats within 100Gb/s and beyond the 100Gb/s. A brief overview over different transmission systems transmitting huge amount of data at channel bit rates up to 1Tb/s or beyond this. In this specific article we survey in a comparative tabular manner to analyse the advantages of digital modulation formats over old analogue modulation formats.
Digital communication is a transfer of information from source to destination in the form of discrete signals. These signals are manipulated by electronic circuits (analog or digital) for making it possible to transmit and receive the data or information. Digital transmission is the physical transfer of data over a point-to-point or point-to-multipoint communication channel such as copper wires (guided and unguided channels), optical fibres, wireless communication channels, and storage media. The data is represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. In communication systems, the noise is an error or undesired random disturbance of a useful information signal, introduced before or after the detector and decoder. The noise is a summation of unwanted or disturbing energy from natural and sometimes man-made sources. If we transmit the baseband signals directly, the signals from different transmitters will get mixed up and the information will be lost. Because of these reasons, we use the technology of modulation, for transmitting message signals effectively for long distances Modulation is the process of varying one or more properties of a high frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted. The main goal of modulation today is to squeeze as much data into the least amount of spectrum possible. That objective, known as spectral efficiency, measures how quickly data can be transmitted in an assigned bandwidth expressed in terms of bits per second per Hz (b/s/Hz). Multiple techniques have emerged to achieve and improve spectral efficiency. There are various analog and digital modulation techniques used to transmit the signals. Due to various advantages of digital signals over analog signals, digital modulation techniques are preferred widely. This paper presents a brief study of different digital modulation methods and their uses for a particular application.
Most of all, we thank Our beloved families for their immeasurable support, encouragement, and patience while working on this project. Without their love and understanding, this book and our project would not have come to fruition.
In wireless communication demand of high data rate transmission is increases rapidly on the other side limited amount of spectrum makes it difficult. For such cases signal modulation is a dominant method for transforming the information signal over the air and the choice of modulation scheme is crucial for wireless communication. In wireless communication, conventional FDM (Frequency Division Multiplexing) does not utilize the bandwidth because there is no frequency subband overlap. OFDM is a technique which provides the full bandwidth utilization by overlapping the sub carriers. In this paper the BER performance for QAM and PSK has been analyzed in the presence of AWGN noise. Further we will investigate the effect of QAM-OFDM for different orders in the presence of frequency selective Rayleigh fading channel through MATLAB simulation.
About the digital modulation techniques that are used in the modern wireless and mobile systems.
For a specialized device or set-up in case of any practical communication related problem definition, a sound communication system consisting of the necessary integral parts is very crucial. As such, the design and an analysis of the various communication system is very critical as it directly effects the performance of the device and also reveals the inherent capacity of the system to produce the desired results. In this respect our topic for this paper is the design and analysis of different digital communication systems with a view to determine the most effective system considering all the parameters so that it can be used for important communication based problems and situations. In the next section we will mainly focus on the design processes of various systems, the theory involved, the simulation results, some special techniques of error correction and also the error performance of the systems.
For a specialized device or set-up in case of any practical communication related problem definition, a sound communication system consisting of the necessary integral parts is very crucial. As such, the design and an analysis of the various communication system is very critical as it directly effects the performance of the device and also reveals the inherent capacity of the system to produce the desired results. In this respect our topic for this paper is the design and analysis of different digital communication systems with a view to determine the most effective system considering all the parameters so that it can be used for important communication based problems and situations. In the next section we will mainly focus on the design processes of various systems, the theory involved, the simulation results, some special techniques of error correction and also the error performance of the systems. Keywords- modulation, digital, communication
The first wireless service was broadcast radio. In this application, information is transmitted to different, possibly mobile, users (see .1). Four properties differentiate broadcast radio from, e.g., cellular telephony:
For a specialized device or set-up in case of any practical communication related problem definition, a sound communication system consisting of the necessary integral parts is very crucial. As such, the design and an analysis of the various communication system is very critical as it directly effects the performance of the device and also reveals the inherent capacity of the system to produce the desired results. In this respect our topic for this paper is the design and analysis of different digital communication systems with a view to determine the most effective system considering all the parameters so that it can be used for important communication based problems and situations. In the next section we will mainly focus on the design processes of various systems, the theory involved, the simulation results, some special techniques of error correction and also the error performance of the systems.
Communication technology has become pervasive in the modern world, and ever more complex. This introductory textbook allows students to understand the principles underlying the reliable transmission of information by focusing on the most basic ideas of digital communications. Carefully paced, logically structured, and packed with insights and illustrative examples, this is an ideal textbook for anyone who wants to learn about modern digital communications. • The simple, logical presentation covers the fundamentals in sufficient detail to allow students to master the basic concepts in digital communications without being overwhelmed. • Step-by-step examples and extensive problem sets, including MATLAB exercises, allow hands on use of the key concepts, to reinforce learning. • Mathematical derivations are complete, but kept clear and simple to ensure a thorough understanding. • Initial chapters provide background material to remind students of the basics. • Advanced topics and applications are also covered to stimulate the reader's interest and appreciation. • Extensive illustrations provide an intuitive understanding of the derivations and concepts. where he has developed and taught undergraduate and graduate courses in signals and systems, digital communications, error control coding, and wireless communications. He currently serves as an Associate Editor for the
For a specialized device or set-up in case of any practical communication related problem definition, a sound communication system consisting of the necessary integral parts is very crucial. As such, the design and an analysis of the various communication system is very critical as it directly effects the performance of the device and also reveals the inherent capacity of the system to produce the desired results. In this respect our topic for this paper is the design and analysis of different digital communication systems with a view to determine the most effective system considering all the parameters so that it can be used for important communication based problems and situations. In the next section we will mainly focus on the design processes of various systems, the theory involved, the simulation results, some special techniques of error correction and also the error performance of the systems. Keywords- modulation, digital, communication
Sameer Shahid, 2019
Communication plays a vital role in our lives, it is impossible to think life without it. it is the basic process of exchanging information or transferring data from one place to another. So, it is very important for us to understand the technology behind it which has made our lives so simple and fast. This paper is about the di erent types of modulation schemes like AM, FM, PM, PAM, PWM, PPM, PCM etc used in the communication system and their importance.
The demand for high-speed mobile wireless communications is growing at a very fast rate. OFDM technology is a key technique for achieving the high data rate and spectral efficiency requirements for wireless communication systems. Orthogonal Frequency Division Multiplexing (OFDM) [3–6] has emerged as a successful air-interface technique. The Orthogonal frequency division Multiplexing was originally developed from the multi-carrier modulation techniques used in high Frequency military radios. This paper presents, using Additive White Gaussian Noise channel (AWGN) and racian channel to studyand compair the performance analysis of Bit Error rate (BER) Vs Signal to Noise ratio (SNR). The model of OFDM with Rician fading channel using simulink in MATLAB is discussed. This model is used for performance enhancement of the OFDM with QPSK and QAM modulation schemes and channel condition. The throughput and packet error rate are used to evaluate the performance of communication with the change in physical layer parameter. The performance analysis of different technique used in the QAM OFDM is compared by visualizing the BER vs SNR curve.
Scholars-Press Publication
In this book deals with the fundamental cellular radio concepts such as frequency reuse and handoff. This also demonstrates the principle of trunking efficiency and how trunking and interference issues between mobile and base stations combine to affect the overall capacity of cellular systems. It presents different ways to radio propagation models and predict the large scale effects of radio propagation. This also covers small propagation effects such as fading, time delay spread and Doppler spread and describes how to measures signal bandwidth. The objective of the student should be made to know the characteristic of wireless channel, learn the various cellular architectures, understand the concepts behind various digital signalling schemes for fading channels and also be familiar the various multipath mitigation techniques and multiple antenna systems. The outcomes of the course, the student should be able to characterize wireless channels, design and implement various signalling schemes for fading channels, design a cellular system, compare multipath mitigation techniques and analyze their performance, design with transmit/receive diversity and MIMO systems.
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