Theoretical analysis of M-ary/SS communication systems using racing counters and a Hadamard matrix

1996 ◽  
Vol 14 (8) ◽  
pp. 1569-1575 ◽  
Author(s):  
K. Ohuchi ◽  
H. Habuchi ◽  
T. Hasegawa
Keyword(s):  
Theoretical Analysis ◽  
Communication Systems ◽  
Hadamard Matrix

scholarly journals Spherical Dielectric Resonator Antenna for 5G Application

2021 ◽  
Author(s):  
Ashok kumar ◽  
Rajveer Singh Yaduvanshi
Keyword(s):  
Wireless Networks ◽  
Wireless Communication ◽  
Theoretical Analysis ◽  
Dielectric Resonator ◽  
Communication Systems ◽  
Return Loss ◽  
Wireless Communication Systems ◽  
Dielectric Resonator Antenna ◽  
Good Match ◽  
Good For

Abstract In this article Spherical DRA has been formulated , simulated and proto type developed. The detailed theoretical analysis along with simulations and measured results at 5.8 GHz have been presented in this article. The SDRA at 5.8 GHz covering 5G frewuenci band. The proposed design antenna provides the gain of 7.3 dB and return loss -25 dB. The measured results are in good match with simulated result. The proposed SDRA are good for 5G wireless networks, as well as other sub-6 band in wireless communication systems.

scholarly journals Theoretical approaches to the synthesis of discrete signals with necessary properties

Radiotekhnika ◽  
2021 ◽  
pp. 25-32
Author(s):  
I.D. Gorbenko ◽  
A.A. Zamula
Keyword(s):  
Information Security ◽  
Information Exchange ◽  
Communication Systems ◽  
Noise Immunity ◽  
Hadamard Matrix ◽  
General Characteristic ◽  
Software Complex ◽  
Theoretical Approaches ◽  
Discrete Signals ◽  
Information And Communication

Methods for information exchange, formation and processing of data used in information and communication systems (ICS), as well as classes of broadband signals used as a physical data carrier, do not provide the necessary (for individual ICS applications) indicators of cyber and information security, noise immunity of reception signals and secrecy of IKS functioning. Most of the existing systems use signals, the construction of which is based on linear laws, which allows an attacker, based on the establishment of the parameters of the signals used in the system, to carry out deliberate interference in the operation of the ICS with minimal energy consumption. The article presents conceptual approaches to the construction of secure ICS, which determine the need to cover the entire spectrum of information transformations in the complex, and based on the synthesis of signal systems with improved ensemble, correlation, structural properties. A method is proposed for synthesizing discrete derivatives of signals based on nonlinear discrete complex cryptographic signals (CS) and orthogonal signals formed on the basis of the rows of the Hadamard matrix (initial signals),. Based on computer modeling and the performed calculations, it is shown that the derivative signals formed on the basis of cryptographic sequences and rows of the Hadamard matrix have improved properties compared to orthogonal and linear classes of signals. Approaches to the construction are stated and a general characteristic of the hardware-software complex for synthesis, analysis, study of properties, generation, processing of a number of studied signal classes is given. It is shown that the use of such signals will improve such indicators of the system functioning as information security, noise immunity of signal reception and secrecy of functioning.

Multi-Mode Narrow-Frame Antenna for 4G/5G Metal-Rimmed Mobile Phones

2020 ◽  
Vol 35 (8) ◽  
pp. 908-915
Author(s):  
Ming Yang ◽  
Yu-Fa Sun ◽  
Tong-Qing Liao
Keyword(s):  
Theoretical Analysis ◽  
Mobile Phones ◽  
Communication Systems ◽  
Return Loss ◽  
Band 3 ◽  
Monopole Antenna ◽  
Experimental Results ◽  
5G Communication ◽  
Multi Mode

A novel multi-mode narrow-frame antenna is presented for 4G/5G metal-rimmed mobile phones in this paper. The proposed antenna is constituted by a monopole antenna and a coupling strip, which is printed on FR4 substrate with thickness of 0.8 mm. The overall area occupied by the antenna is only 60 × 10.4 mm2, which can be used as a promising narrow-frame antenna. The simulated results shows that the return loss of the antenna can provide four operating bandwidths of 822– 961 (band 1), 1697–3075 (band 2), 3280–3835 (band 3) and 4475–5050 MHz (band 4), which respectively cover 824–960, 1710–2690, 3300–3600 and 4800–5000 MHz in 4G/5G communication systems. In order to verify the accuracy of theoretical analysis and simulated results, the proposed antenna is fabricated and measured. The experimental results are basically consistent with the simulated results, suggesting that the presented antenna has attractive performance for mobile phones.

scholarly journals The Distribution of the Ratio of the Products of Two Independentα-μVariates and Its Application in the Performance Analysis of Relaying Communication Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ana Matović ◽  
Edis Mekić ◽  
Nikola Sekulović ◽  
Mihajlo Stefanović ◽  
Marija Matović ◽  
...  
Keyword(s):  
Distribution Function ◽  
Performance Analysis ◽  
Probability Density Function ◽  
Theoretical Analysis ◽  
Communication Systems ◽  
Cumulative Distribution Function ◽  
Cumulative Distribution ◽  
Wireless Communication Systems ◽  
Multihop Wireless ◽  
Probability Density Function Pdf

We present novel general, simple, exact, and closed-form expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the ratio of the products of two independentα-μvariates, where all variates have identical values of alpha parameter. Obtained results are applied in analysis of multihop wireless communication systems in different fading transmission environments. The proposed theoretical analysis is also complemented by various graphically presented numerical results.

scholarly journals Introduction to Communication Systems

2021 ◽  
pp. 1-17
Author(s):  
Stevan Berber
Keyword(s):  
Theoretical Analysis ◽  
Time Domain ◽  
Communication Systems ◽  
Theoretical Concepts ◽  
Analysis And Design ◽  
The Subject ◽  
Definition Of ◽  
The Time Domain ◽  
Analogue To Digital ◽  
Power And Energy

This chapter introduces the subject of the book, defines the main terms in communication systems that will be used in the book, and presents the objectives of the book. It also presents classifications of signals and systems, and theoretical concepts related to the signal conversions in the time domain that will be used in subsequent chapters. The signals are classified using various criteria, including periodicity and symmetry, continuity and discreteness, power and energy properties, randomness, and physical realizability of signals. Analogue-to digital and digital-to-analogue conversions and their places and importance in the processing of signals in relation to their application in communication systems are briefly explained. The final section returns back to the definition of the signals related to the continuity and discreteness in time and their values, due to the importance of distinguishing them in the theoretical analysis and design of digital and discrete communication systems.

Theoretical analysis of interference in satellite communication systems when using multistation access with code division of channels

2020 ◽  
Vol 4 ◽  
pp. 7-12
Author(s):  
Alexey Musaev ◽  
◽  
Sergey Zinkin
Keyword(s):  
Theoretical Analysis ◽  
Communication Systems ◽  
Satellite Communication ◽  
Experimental Studies ◽  
Radio Resource ◽  
Channel Separation ◽  
Effective Use

Abstract. To ensure the most effective use of the limited radio resource of the repeater, various methods of multistation access of earth stations to the repeater are developed and applied, based on one or another method of channel separation. The article presents a theoretical analysis of the occurrence of mutual and combination interference in satellite communication systems when using multi -station access with code separation of channels. Recommendations for further experimental studies are proposed.

scholarly journals Indoor multiuser visible light communication systems using Hadamard-coded modulation

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190183 ◽  
Author(s):  
Jie Lian ◽  
Mohammad Noshad ◽  
Maïté Brandt-Pearce
Keyword(s):  
Wireless Communication ◽  
Visible Light ◽  
Communication Systems ◽  
Hadamard Matrix ◽  
Coded Modulation ◽  
Optical Wireless Communication ◽  
Visible Light Communications ◽  
Optical Wireless ◽  
Entire Area ◽  
Indoor Space

Visible light communications (VLC) is a short-range optical wireless communication technology that uses light-emitting diodes (LEDs) as lighting devices and data transmitters. This paper describes a multiuser VLC system using Hadamard-coded modulation (HCM) for indoor data transmission. Considering the peak transmitted power limit of the LEDs, a DC-reduced HCM (DCR-HCM) is used to reduce the nonlinear clipping distortion. Since the Hadamard codewords have different bandwidth requirements for a given symbol rate, they can be assigned to users with varying hardware capabilities. Optimally assigning codewords to users is found to significantly improve the average throughput, up to twice higher than a random assignment for a typical scenario. When the number of active users is less than the size of the Hadamard matrix used, more than one codeword can be assigned per user, which further improves the throughput. This paper also examines a scenario where multiple lamps in an indoor space transmit the same data. Since the time of arrival for the received signals emitted from different lamps is different, the Hadamard codes received are no longer orthogonal, resulting in multiple access interference and inter-chip interference. The number of acceptable codewords is computed based on the specific interference experienced in different parts of the indoor space. The spatial distribution of the maximum throughput is also simulated, showing that the ratio of the maximum to the minimum data rate can be as high as 10 when considering the entire area of a typical indoor room. This article is part of the theme issue ‘Optical wireless communication’.

Theoretical analysis of optical pulse position modulation communication systems using semiconductor lasers

1991 ◽  
Vol 23 (8) ◽  
pp. 1077-1089 ◽  
Author(s):  
G. Aureli ◽  
S. Betti ◽  
G. De Marchis ◽  
E. Iannone ◽  
A. Mecozzi
Keyword(s):  
Theoretical Analysis ◽  
Semiconductor Lasers ◽  
Communication Systems ◽  
Optical Pulse ◽  
Pulse Position Modulation
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