Broadband Wireless Access Systems Research Articles

SYSTEM OBJECTS – A NEW TECHNOLOGY FOR STUDYING SIMULATION MODELS OF RADIO ENGINEERING SYSTEMS IN MATLAB

Most of the best universities in the world have adopted MATLAB as a unified software environment in almost all areas of training in all courses of study. The purpose of this work is to illustrate the level of simplicity of programming a simulation modeling of the transmission channel of a wireless broadband access system built on the most modern and future-proof MIMO technology. This can be done without much time, since the developer of the MATLAB product, MathWork, monitors the emergence of new technologies in the field of communications and constantly creates examples of the use of its products for the research and design of new communications equipment, providing them with a detailed description and recommendations for users around the world on how to independently create radio engineering devices and systems. The subject of consideration is object programming technology. Using a particular example, it is shown that the introduction of this technology into the educational process allows not only to reduce the time spent on programming for a computer by several times when students perform experimental studies of radio engineering systems and devices through their simulation, but also to significantly simplify the dialogue between the student and the computer in an interactive mode.

Substantiation of technical characteristics of promising high-speed multi-band broadband military radio stations

The issue of improving the technical characteristics of promising high-speed multi-band broadband military radios is an important issue. It happens because of the increase in the number of devices of communication in information and telecommunication networks, as well as the growing requirements for the level of technical characteristics of these devices. Given the above, the object of the research is a promising high-speed multi-band broadband military radios. The subject of the research is the technical characteristics of promising high-speed multi-band broadband military radios. In the course of the research, classical methods of analysis and synthesis were used. The research analyzes global trends in the construction and development of wireless access networks, which allows concluding on the prospects of development (purchase) and implementation of high-speed multi-band broadband military radios for the Armed Forces of Ukraine. The results of the analysis of characteristics and parameters of high-speed multi-band broadband radio stations of the world's leading countries allow to determine the main features and requirements for promising radios, as well as to substantiate the use of high-speed radio stations in the Armed Forces of Ukraine. The conditions and factors influencing the possibilities of using promising broadband radio stations in the conditions of modern wars and armed conflicts are determined. The analysis allows to conclude that broadband radio access systems will be used to organize access to information resources in the information and telecommunications environments of network-centric and information wars.

Efficient and reliable hybrid deep learning-enabled model for congestion control in 5G/6G networks

Future generation networks such as millimeter-wave LAN, broadband wireless access systems, and 5th or 6th generation (5G/6G) networks demand more security, low latency with more reliable standards and communication capacity. Efficient congestion control is considered one of the key elements of 5G/6G technology that allows the operators to run various network instances using a single infrastructure for a better quality of services. Artificial intelligence (AI) and machine learning (ML) are playing an essential role in reconfiguring and optimizing the performance of a 5G/6G wireless network due to a vast amount of data. A smart decision-making mechanism is required for the incoming network traffic to ensure load balancing, restrict network slice failure and provide alternate slices in case of slice failure or overloading. To circumvent these issues, a hybrid deep learning-enabled efficient congestion control mechanism is proposed in this paper. This hybrid deep learning model consists of long short term memory (LSTM) and support vector machine (SVM). The applicability of the proposed model is validated by simulating for one week using multiple unknown devices, slice failure conditions, and overloading conditions. An overall accuracy rate of 93.23% is calculated for the proposed hybrid model that reflects the applicability. Apart from this, other performance metrics such as specificity, recall, time consumption, varying training, test sets, true-false rates, and f-score were used for the performance evaluation purposes of the proposed model.

Implementation of Convolutional Codes with Viterbi Decoding in Satellite Communication Link using Matlab Computational Software

This paper describes the design of convolutional encoders encoding broadband data with coding rates (r) 3/4 and 5/6 at the transmitter, and the Viterbi decoders for the decoding of the encoded data with same coding rates at the receiver. This design uses BPSK (Binary Phase Shift Keying) modulating scheme in an AWGN (Additive White Gaussian Noise) channel in analysing the BER (Bit-error rate) performance of next generation broadband wireless access systems. The constraint length of the convolutional encoder is K=7, with number of states n=2k-1, and the design was implemented using Matlab Computational Software. The higher coding rates of the convolutional encoders were achieved using puncturing codes and de-puncturing codes for the corresponding Viterbi decoders. In satellite network design, it is vital to compliment the system design with the BER requirement of the network. Plots of BER against SNR ( ) were made for the various coding rates and for data rates of 50000 bits and 12000 bits. The results were analysed based on comparison of coding gain obtained for the different coding rates, theoretical BER and calculated BER. In this paper, Matlab simulation of the convolutional encoder and Viterbi decoder shows improved coding gain for higher data rates and data sequences.

НАРУЖНАЯ ПЛАНАРНАЯ АНТЕННАЯ РЕШЕТКА МОБИЛЬНОГО ИНТЕРНЕТА 3G/4G

Internet antennas-busters are one of the most common antennas of suburban subscriber stations of broadband radio access systems. In many ways, the speed of information transmission in such systems limits the signal level provided by the base station in the entire operating band of the Internet signal. Since the antenna located on the wall of the house is stationary, it can be made relatively large, which allows you to implement a higher gain and accordingly increase the signal level on the router. At the same time, the market for such antennas is quite saturated with a wide variety of antenna designs, but due to the increase in the number of people working in remote mode and the expected transition to mobile communication systems 5G, it still continues to develop rapidly. The paper proposes a new design of the transceiver mobile Internet antenna-buster, whose main advantage is absolute imperceptibility when installed outdoors. We consider a planar in-phase 8-element antenna array installed on the window glass of a suburban building. As the individual emitters of the lattice are encouraged to use a planar wave dipoles. A feeding scheme for the antenna array on flat two-wire lines has been developed, which provides in-phase and almost equal amplitude excitation of all array elements of the array. Calculations of antenna radiation patterns in the range of 1700-2700 MHz are given. It is shown that the developed antenna has a gain of 8-9 dB in the range of 1700-2100 MHz and 10-12 dB in the range of 2400-2700 MHz. These values are practically not inferior to similar indicators of known collinear antenna arrays and in the upper part of the work range, they have a gain of 1-2 dB compared to their analogs. A planar array matching scheme has been developed that provides a VSWR of about 2.5 in the range of 1700-2100 MHz and no worse than 2 in the range of 2400-2700 MHz. Variants of constructing planar antenna arrays with broadband emitters that provide similar matching without the use of additional matching devices are presented.

A Fair and Efficient Packet Scheduling Scheme for IEEE 802.16 Broadband Wireless Access Systems

A Fair and Efficient Packet Scheduling Scheme for IEEE 802.16 Broadband Wireless Access Systems

Performance Comparison of Handover mechanisms in mobile wireless communication networks for Broadband Wireless Access Systems

Mobility is the mobile communication characteristics which make it diverse and attractive for all. Wireless communication is now attractive to the whole world and provides the ability of users to communicate very active. Transferring the users from one radio network to another is accomplishing the IT. The process is called the handover process. The transfer takes place by adjusting the duration of the soft transfers, the area size and either by cell crossing or by deterioration in the signal quality of the current channel — the brief overview of handover, Handover in WiMAX and LTE, types of handover, handover types solutions, approaches used in literature are typically transfer parameters and I contemporary the convergent fact for continuance in the area of mobile and wireless communication Handover.

THE INCREASE OF THE ENERGY EFFICIENCY OF THE RADIO EQUIPMENT BASED ON THE USE OF MODULATION BY ORTHOGONAL HARMONIC CARRIERS

Most of the theoretical results, as well as methods using OFDM modulation, are obtained in order to increase the rate of information transmission with energy constraints and the bandwidth. For broadband radio access systems, this task is primarily due to the commercial purpose of these systems and the desire of the communications developers to provide high-speed wireless access to the Internet as much as possible at the same time. This article is devoted to the issue of increasing the energy efficiency of radio equipment using modulation orthogonal harmonic carriers under conditions of intentional interference and frequency-selective fading while ensuring a given level of reliability and speed of information transmission.

ABOUT RELATIONSHIP BETWEEN THE SIGNAL POWER, NUMBER OF M-QAM POSITIONS AND NOISE IMMUNITY IN BROADBAND WIRELESS ACCESS SYSTEMS

Is studied the effect of measurement error on the accuracy of selecting the modulation type in the transmitter of the base station. The article discusses changes in the statistical characteristics of the measured signal as it passes through the stage of the feedback loop of the system of the LMDS type. Probabilistic characteristics of pilot-signal are determined at the output of this loop. The aim of the work was to find a compromise between the type of modulation and the power of the BS transmitter to maintain the transmission faithfulness within the given limits in the forward channel of an interactive wireless broadband radio access system of the LMDS. In this system a transition is made from one type of modulation to another in order to maintain the noise immunity of the system within the admissible limits. An adaptive controlling method of modulation type makes it possible to obtain an energy gain in the forward channel of the system. It is useful to determine the type of modulation by measuring the current value of the signal-to-interference ratio at the base station (BS) receiver. For this purpose a pilot signal is transmitted on the reverse channel of the system. This signal, passing through the turbulent medium, undergoes attenuation, and therefore at the input of the BS receiver we have a random process. Moreover, the distribution law of this process can be different and is determined by the communication channel model. The problem consisted in determining the necessary probabilistic characteristics of the output process by using the system parameters and probabilistic characteristics of the input random process. For this purpose the cumulants of the input random process and the random process at the output of the linear inertial system are determined. An expression for the probability density of the random process at the output of a linear inertial system is obtained. The graphics of the error probability on the energy parameter at 16-QAM and 64-QAM type of modulation are constructed. The influence of the measurement error on the accuracy of the choice of the modulation type in the transmitter of the BS is studied. The limits of the change in the energy parameter are defined graphically, under which the modulation type changes to ensure a given error probability. It is determined, that the system is more critical to the measurement error at high admissible error probability, i.e. at high error probabilities, small errors in the measurement of the signal-to-noise ratio make it necessary to transition to a more noise-immune modulation mode.

ELECTROMAGNETIC CONDITIONS HYGIENIC ASSESSMENT AT WORKPLACES WITH PERSONAL COMPUTERS: HISTORY AND PRESENT STATUS

Introduction. Currently, in force hygienic normative-methodical documents (SanPiN 2.2.2/2.4.1340-03, SanPiN 2.2.2/2.4.2620-10, SanPiN 2.2.4.3359-16) do not allow to objectively estimating EMF on modern workplaces of personal computers (PCs) users by and other means of information and communication technologies (ICT). Aim of the study is scientific substantiation of improvement of normative-methodical documentation on hygienic regulation and evaluation of EMF in computerized workplaces using modern ICT. Material and methods. The analytical method of evaluation of modern normative-methodical documentation regulating hygienic norms and methods of evaluation of EMF in the workplace of PC users is used. More than 11 thousand measurements of EMF levels were carried out. Results. A critical analysis of the current hygienic regulations of EMF in the workplace of PC users and other means of ICT in Russia showed they to be not scientifically justified, and the existing methodology does not allow an adequate hygienic assessing of the electromagnetic environment (EME). The main sources forming EME on modern workplaces of PC users are both PCs, and switching power supplies, network support devices (UPS), cable lines, wiring, broadband wireless access systems (base stations, Wi-Fi routers, access points, external and built-in laptops USB modems), cell phones, lamps of local and general lighting. EMFs on a workplace of PC users are characterized by complex amplitude-frequency composition: electric and magnetic fields at frequencies of 30 Hz - 300 kHz, EMF at frequencies above 300 MHz, electrostatic fields, hypogeomagnetic fields. New EMF hygienic standards at workplaces of PC users and other means of ICT are scientifically proved. Conclusion. The introduction of new regulations will ensure an adequate hygienic assessment of EMF in the workplaces of PC users in each normalized frequency band in total from all sources and will eliminate the current contradictions and shortcomings. The introduction of new EMF hygienic standards in the practice of sanitary and epidemiological supervision will preserve the health of the PC users and other ICT facilities.

An optimal bandwidth allocation algorithm for improving QoS in WiMAX

In the last few years, the term “quality of service” has become increasingly synonymous with digital cellular networks and has greatly influenced the way we manage network traffic. The IEEE 802.16 standard is a broadband wireless access system that enables high speed data transfer over large distances. It is one of the standards that meet the IMT-Advanced specifications. It also incorporates a quality of service framework to provide quality of service to both realtime and non-realtime multimedia applications. One of the critical contributions of a QoS framework is efficient scheduling of network traffic. This paper dilates on a two-level scheduling algorithm for base station uplink scheduler to provide quality of service to various classes of traffic. The proposed algorithm ensures efficient and fair multimedia transmission. We also deliberated on a video transmission framework based on the proposed algorithm. The performance of two-level scheduling algorithm has been extensively analyzed through simulations and the results have effectively established the efficacy of the proposed algorithm. The results reveal that the the proposed algorithm is able to fairly and efficiently schedule network traffic while ensuring quality of service for all classes of traffic.

Cell search and synchronization in 5G NR

An overview of the physical signals foreseen by the 3GPP 5G New Radio specification for frame synchronization and cell search in fifth- generation wireless broadband access systems is presented in the paper. The frame synchronization algorithm and the cell initialization procedure are demonstrated. An estimate of probability of error detection of a physical identifier by the signals of the primary and secondary synchronization is obtained. The comparison of the successful synchronization in AWGN channel for 4G LTE and 5G NR is shown.

Combined centralised and distributed mechanism for utilisation of node association in broadband wireless network

Mobile broadband wireless access system has the stations that might be fixed, nomadic or mobile. Regarding the mobility, the node association procedure is critical for network entry as well as network re-entry during handover. The flexibility and utilisation of MAC protocols scheduling have an important role. The standard provides the Partition Scheme as the scheduling mechanism which separates the allocation of minislots for scheduling. However, minislots cannot be flexibly reserved for centralised and distributed scheduling. In this paper we analysed the scheduling mechanism to improve the utilisation of minislots allocation during the exchange of MAC massages. The centralised and distributed scheduling is implemented in some topology scenarios. The result shows the proposed mechanism has better performance for node association than partition scheme.

Entropy Analysis of Broadband Wireless Access Systems

A Broadband Wireless Access (BWA) system consists of a base station and a set of $M$ users within its antenna sector, with $N$ simultaneously active users, $0\le N\le M$ , working in Point-to-Multipoint (PMP) mode. We model this system as family of Birth–Death Processes (BDPs), with size $M+1$ , in equilibrium, indexed by system utilization parameter $\rho$ , ratio of its primary birth and death rates. Relying on the fundamental concepts of system information $i$ and system entropy $S=E(i)$ , we develop an entropy analysis of BWA systems. Thereby, by definition, the system entropy, as the mean value of system information, is the uncertainty, related to the system. Taking system information as loss function, we identify risk and uncertainty, related to the system. Using the maximization of entropy, given the average number $\overline{N}$ of active users, we promote belt-zone of deviation from maximum uncertainty and a function of relative risk, regarding $\overline{N}$ , for a BWA system. This analysis is illustrated on BWA systems with finite user population, such as the binomial $M$ -server BWA systems, modeled by the family of BDPs with binomial distribution, and the delay single-server BWA systems, modeled by the corresponding family of BDPs; both systems represent private networks.

An Uncertainty Quantification methodology for Broadband Wireless Access systems

A Broadband Wireless Access (BWA) system comprises a Base Station and a group of M users in its vicinity, simultaneously serving N active users, N∈{0,1,2,…,M}, in Point-to-Multipoint (PMP) fashion. Depending on the concepts of system information and system entropy (i.e., mean information) we promote an Uncertainty Quantification (UQ) methodology for BWA systems. We evaluate the measures: system entropy (which represents the uncertainty, inherent to any system), average number of simultaneously active users, system resource utilization and availability, and average throughput per user, with respect to the parameters: system utilization and system size. Entropy is studied through its both components: nominal part and additional part. In information linear BWA system the additional part of entropy vanishes. Moreover, this methodology offers an entropy-based procedure for system utilization parameter estimation, showing that Maximum Likelihood Method (as an estimation procedure) and Fisher Information (as an uncertainty measure) can be successfully applied only to the information linear BWA system. Thus, the change of BWA system features is inherently built in this approach through the change of entropy additional part. Further, using the function of relative risk, given the active user average number, we quantitatively show that smallest uncertainty is associated to the Binomial BWA system (representing a private network), greater to the Erlang loss BWA system, and greatest at all to the information linear BWA system (both representing public networks), where the quantity N obeys Binomial, truncated Poisson and truncated geometrical distribution, respectively.

Performance analysis of filter bank multicarrier system with non‐linear high power amplifiers for 5G wireless networks

The filter bank multicarrier (FBMC) with offset quadrature amplitude modulation (OQAM) is one of the alternative modulation schemes to orthogonal frequency division multiplexing for next generation broadband wireless access systems. The non-linearity of high-power amplifiers (HPA) has a crucial effect on the performance of FBMC systems. In this study, the impacts of non-linear distortion effects are considered in a FBMC-OQAM system when the signal is passed through a HPA for medium- and high-power signals which are modelled as amplitude and phase distortions. Specifically, memory-less HPA non-linear distortion models such as solid-state power amplifier (SSPA), soft-envelope limiter (SEL), travelling wave tube amplifier are proposed for FBMC systems. A closed-form expression for bit error rate expression is derived and analysed for SSPA and SEL models for FBMC/OQAM system with non-linear HPA in frequency-selective Rayleigh channel by varying constellation size in OQAM modulation and input back-off. The performance is compared for the models with 64 sub-channels and input back-off for 6 and 8 dB. In lieu of validating the obtained simulation results, theoretical results are being compared.

Method of contour integrals for the analysis of complex nonlinear distortions of narrowband Gaussian random processes

The method of contour integrals can be used to analyze interference in radio equipment of modern broadband radio-access systems resulting from the presence of nonlinear devices (NDs) with amplitude-to-phase conversion. Several nonlinear models of power amplifiers are considered as such devices. The analysis of interference is reduced to the determination of the interference power density at the ND output and the signal-to-interference ratio in the fundamental band of the signal.

Degrading the Effect of Channel Impairment on STBC-OFDM System in Rayleigh Fading Channel

This paper indicates the space time block code provides transmit diversity in wireless fading channel during the STBC-OFDM system. OFDM is enforced in broadband wireless access systems as the way to beat wireless channel impairments and to enhance and breadth potency. This research is to analyze the performance of non STBC-OFDM system and STBC-OFDM system. The performance has been evaluated for construction modulation (QAM) technique for orthogonal frequency division multiplexing (OFDM) systems using multiple transmit diversity antenna system in the channel. Conjointly the equation of SNR and BER has been derived for 16-QAM for multiple transmit and receive antenna for STBC-OFDM system by considering the have an effect on of Inter-symbol interference (ISI), phase noise and temporal arrangement noise in Raleigh fading channel.

A methodology for information and capacity analysis of broadband wireless access systems

Using a part of a general methodology for population analysis, developed recently in Lazov and Lazov [1], and relying on the fundamental concepts of system information i and system entropy $$S=E\left( i \right) $$S=Ei, this paper promotes a methodology for information and capacity analysis of broadband wireless access (BWA) systems. A BWA system consists of a base station (BS) and a group of M users in its coverage area, with N simultaneously active users, $$0\le N\le M$$0≤N≤M, working in point-to-multipoint mode. As in [1], we model this system as family of birth-death processes (BDPs), with size $$M+1$$M+1, in equilibrium, indexed by the system utilization parameter $$\rho $$ź, ratio of its primary birth and death rates, $$\rho =\lambda /\mu $$ź=ź/μ. We evaluate the BWA system information and entropy, and full system capacity, and then, assuming the same Gaussian distribution for the arrival traffic at BS from any user, system capacity (as a function of the system information) and its mean value, and mean normalized square deviation of the system capacity from its linear part. We compare the information of empty $$\left( {N=0} \right) $$N=0 and full $$\left( {N=M} \right) $$N=M system with system entropy, and further, system mean capacity with full system capacity, as functions of parameter $$\rho $$ź. The developed methodology is illustrated on families of BDPs with truncated geometrical, truncated Poisson and Binomial distributions as their equilibrium ones, which model the information linear, Erlang loss and Binomial BWA systems, respectively.

Utility-based Scheduling Frameworks to Provide Efficient Quality-of-Service Differentiation in a Mixture of Real-time and Non-real-time Traffics

This paper proposes a utility-based scheduling framework for efficient differentiation of users’ Quality-of-Service (QoS) in a broadband wireless access system involving heterogeneous mixed traffic flows. The utility-based scheduling framework, called Maximum QoS Satisfaction (MQS), is based on three novel Radio Resource Allocation (RRA) techniques; delay-based scheduling policy for Real-Time (RT), minimum-rate-based scheduling policy for Non-Real-Time (NRT) and a throughput-based scheduling policy for Best-Effort (BE) services. Simulation study shows that MQS achieves superior performances in terms of average system throughput and user satisfaction both in single and heterogeneous mixed traffic scenarios, when compared to some existing ones.