Digital Bandpass Modulation Methods

2021 ◽  
pp. 215-304
Author(s):  
Stevan Berber
Keyword(s):  
Communication Systems ◽  
Orthonormal Basis ◽  
System Structure ◽  
Special Cases ◽  
Frequency Domains ◽  
Shift Keying ◽  
Modulation Methods ◽  
Power And Energy ◽  
Digital Communication Systems ◽  
Generic System

This chapter presents mathematical models of baseband and bandpass digital communication systems based on binary and quaternary phase-shift keying, frequency-shift keying, and quadrature amplitude modulation. The systems are deduced as special cases from the general generic system structure and the related theory of orthonormal basis functions. The systems are uniquely presented using mathematical operators and detailed derivatives for signals in time and frequency domains at the system’s vital points, that is, the transmitter, the receiver, and the noise generator, using the concepts of both stochastic (continuous and discrete) and deterministic (continuous and discrete) signal processing. The vital characteristics of the system and its blocks are expressed in terms of amplitude spectral density, autocorrelation functions, power and energy spectral densities, and bit error probability.

Discrete Bandpass Modulation Methods

2021 ◽  
pp. 305-385
Author(s):  
Stevan Berber
Keyword(s):  
Phase Shift ◽  
Discrete Time ◽  
Time Domain ◽  
Communication Systems ◽  
Intermediate Frequency ◽  
System Structure ◽  
Phase Shift Keying ◽  
Shift Keying ◽  
Modulation Methods ◽  
Power And Energy

This chapter presents mathematical models of discrete baseband and bandpass communication systems based on binary phase-shift keying, quaternary phase-shift keying, frequency-shift keying, and quadrature amplitude modulation. The operation of intermediate-frequency systems where all processing is performed in the discrete-time domain are presented. The systems are deduced as special cases from a generic system structure that is based on the application of orthonormal basis functions. The block schematics of systems are uniquely presented using mathematical operators. Detailed derivatives are presented for signals in the discrete-time domain at the vital points of the system’s structure, using the concepts of both discrete stochastic and discrete deterministic signal processing. The vital characteristics of the discrete system and its blocks are expressed in terms of amplitude spectral density, autocorrelation functions, power and energy spectral densities, and bit error probability.

Operation of a Discrete Communication System

2021 ◽  
pp. 172-214
Author(s):  
Stevan Berber
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Likelihood Function ◽  
System Structure ◽  
Mathematical Expressions ◽  
System P ◽  
Special Cases ◽  
Shift Keying ◽  
Correlation Receiver ◽  
Discrete Counterpart

In this chapter, based on definitions of signal synthesizers and analysers, a general and generic scheme of a discrete communication system is developed in order to deduce practical systems as its special cases. The synthesizer is transferred into a discrete transmitter, and the analyser is used as a correlation receiver followed by an optimum detector. The system structure is presented in terms of mathematical operators and supported by exact mathematical expressions based on the theory of discrete-time stochastic processes. The likelihood function is derived, and the maximum likelihood rule is applied to specify the decision process and construct the optimum detector. A multilevel system and a quadrature phase-shift keying system are deduced as special cases, and the bit error probability expression is derived. For the sake of continuity and completeness in presenting communication systems theory, a generic digital communication system is developed and related to its discrete counterpart.

scholarly journals Application of Ultra Narrow Band Modulation in Enhanced Loran System

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4347
Author(s):  
Boyun Lyu ◽  
Yu Hua ◽  
Jiangbin Yuan ◽  
Shifeng Li
Keyword(s):  
Narrow Band ◽  
Data Rate ◽  
Modulation Method ◽  
Phase Shift Keying ◽  
Spectrum Utilization ◽  
Frequency Domains ◽  
Shift Keying ◽  
Modulation Methods ◽  
Binary Phase Shift Keying ◽  
Signal Time

The Enhanced Loran (eLoran) system is valued for its important role in the positioning, navigation, and timing fields; however, with its current modulation methods, low data rate restricts its development. Ultra narrow band (UNB) modulation is a modulation method with extremely high spectrum utilization. If UNB modulation can be applied to the eLoran system, it will be very helpful. The extended binary phase shift keying modulation in UNB modulation is selected for a detailed study, parameters and application model are designed according to its unique characteristics of signal time and frequency domains, and it is verified through simulation that the application of this modulation not only meets the design constraints of the eLoran system but also does not affect the reception of the respective signals of both parties. Several feasible schemes are compared, analyzed, and selected. Studies have revealed that application of UNB modulation in the eLoran system is feasible, and it will increase the data rate of the system by dozens of times.

A Beamformer Employing Pseudo-Interference Technique for Digital Communication Systems

2011 ◽  
Vol 403-408 ◽  
pp. 1214-1217
Author(s):  
Yi Chu ◽  
Wei Yau Horng
Keyword(s):  
Communication Systems ◽  
Superior Performance ◽  
Adaptive Array ◽  
Phase Shift Keying ◽  
Excellent Performance ◽  
Shift Keying ◽  
Gain Errors ◽  
Binary Phase Shift Keying ◽  
Digital Communication Systems ◽  
Array Gain

This paper presents a new receiver for antenna array to provide robustness against adaptive array imperfections. These imperfections include the array gain errors and the directional mismatch. The superior performance of the proposed receiver is primarily achieved by adding an injected pseudo-interference in the diagonally loaded Capon beamformer. Simulation results demonstrate that the proposed method has excellent performance for both binary phase shift keying (BPSK) and quadrature amplitude modulation (QAM) systems.

scholarly journals Pseudorandom Sequences in Spread-Spectrum Communications Generated by Cellular Automata

2012 ◽  
Vol 10 (5) ◽  
Author(s):  
F.C. Ordaz-Salazar ◽  
J.S. González-Salas ◽  
E. Campos-Cantón ◽  
H.C. Rosu
Keyword(s):  
Cellular Automata ◽  
Spread Spectrum ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Pseudorandom Sequence ◽  
Pseudorandom Sequences ◽  
Information Signal ◽  
Shift Keying ◽  
Golden Code ◽  
Digital Communication Systems

Dynamical systems methods have been recently used in spread-spectrum digital communication systems. Theexpansion of the spectrum using a pseudorandom sequence with a higher frequency than the information signal is thekey feature for its robustness against the signal traveling interference through the channel. In this work, we propose togenerate pseudorandom sequences by employing cellular automata and we check these sequences have thenecessary properties which are required in modern communication systems. The computed sequences obtained bythe cellular automata are tested in a quadrature phase shift keying (QPSK) spread-spectrum communication system.The efficiency of the system is analyzed by computing the bit error rate under different signal to noise ratio conditions.These results are compared with systems that employ Golden code and other typical pseudorandom sequences.

Security Analysis of Wireless Authentication Protocols

2019 ◽  
Vol 9 (2) ◽  
pp. 247-252 ◽  
Author(s):  
Ashish Joshi ◽  
Amar Kumar Mohapatra
Keyword(s):  
Execution Time ◽  
Communication Systems ◽  
Security Analysis ◽  
Cryptographic Protocols ◽  
Command Line ◽  
Time Analysis ◽  
Authentication Protocols ◽  
Replay Attack ◽  
Peer Communication ◽  
Digital Communication Systems

Background & Objective: Cryptographic protocols had been evident method for ensuring con dentiality, Integrity and authentication in various digital communication systems. However the validation and analysis of such cryptographic protocols was limited to usage of formal mathematical models until few years back. Methods: In this paper, various popular cryptographic protocols have been studied. Some of these protocols (PAP, CHAP, and EAP) achieve security goals in peer to peer communication while others (RADIUS, DIAMETER and Kerberos) can work in multiparty environment. These protocols were validated and analysed over two popular security validation and analysis tools AVISPA and Scyther. The protocols were written according to their documentation using the HLPSL and SPDL for analysis over AVISPA and Scyther respectively. The results of these tools were analysed to nd the possible attack an each protocol. Afterwards The execution time analysis of the protocols were done by repeating the experiment for multiple iterations over the command line versions of these tools.As the literature review suggested, this research also validates that using password based protocols (PAP) is faster in terms of execution time as compared to other methods, Usage of nonces tackles the replay attack and DIAMETER is secure than RADIUS. Results and Conclusion: The results also showed us that DIAMETER is faster than RADIUS. Though Kerberos protocol was found to safe, the results tell us that it is compromisable under particular circumstances.

scholarly journals Study of 5G-NR-MIMO Links in the Presence of an Interferer

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 732
Author(s):  
Avner Elgam ◽  
Yael Balal ◽  
Yosef Pinhasi
Keyword(s):  
Mobile Networks ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Local Area ◽  
Maximum Energy ◽  
Base Station ◽  
Small Cells ◽  
Diversity Coding ◽  
Shift Keying ◽  
Input Multiple Output

Many communication systems are based on the Multiple Input, Multiple Output (MIMO) scheme, and Orthogonal Space–time Block Transmit diversity Coding (OSTBC), combined with Maximal Ratio Receive Combining (MRRC), to create an optimal diversity system. A system with optimal diversity fixes and optimizes the channel’s effects under multi-path and Rayleigh fading with maximum energy efficiency; however, the challenge does not end with dealing with the channel destruction of the multi-path impacts. Susceptibility to interference is a significant vulnerability in future wireless mobile networks. The 5th Generation New Radio (5G-NR) technologies bring hundreds of small cells and pieces of User Equipment (UE) per indoor or outdoor local area scenario under a specific Long Term Evolution (LTE)-based station (e-NodeB), or under 5G-NR base-station (g-NodeB). It is necessary to study issues that deal with many interference signals, and smart jammers from advanced communication equipment cause deterioration in the links between the UE, the small cells, and the NodeB. In this paper, we study and present the significant impact and performances of 2×2 Alamouti Phase-Shift Keying (PSK) modulation techniques in the presence of an interferer and a smart jammer. The destructive effects affecting the MIMO array and the advanced diversity technique without closed-loop MIMO are analyzed. The performance is evaluated in terms of Bit Error Rate (BER) vs. Signal to Interference Ratio (SIR). In addition, we proved the impairment of the orthogonal spectrum assumption mathematically.

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