Comparative Examination of CO-OFDM Formats for Varied Fiber-Length and Bit Rate

The use of multiple carriers in Orthogonal Frequency Division Modulation (OFDM) makes it bandwidth-efficient and suitable for modern communication such as Long-Term Evolution (LTE), Digital Subscriber Line (DSL) internet access, optical fiber communication, digital television, audio broadcasting, etc. In this paper, four modulation formats by using Coherent Optical Orthogonal Frequency Division Modulations (CO-OFDM) have been analyzed. These are Single Port Dual Polarization (SP DP) 16 QAM, Single-Port Single Polarization (SP SP) 16 QAM, Dual Port Single Polarization (DP SP) QPSK 16-QAM, and Single Port Dual Polarization (SP DP) QPSK. Operation characteristics such as Bit Error Rate (BER) versus fiber-length and BER versus bit-rate have been examined. The range of fiber length used for this investigation is from 0 Km to 1000 Km with loop count equal to 2 and the range of bit rate of operation is from 20 Gbps to 200 Gbps. The present investigation helps in determining the relative suitability of CO-OFDM formats at various bit-rates of operation for different fiber lengths.

Influence of non-stationary interference in analyzing information models with one and several carrier modulation

The aim of the study is to try to analyze the most common mechanisms of impulse noise impact on data transmitted in the symbols of single-carrier and multi-carrier modulation systems. The paper solves the problem of a qualitative analysis of the destructive effect of impulse noise on the possibility of restoring symbols of digital modulation systems operating on the basis of a copper cable infrastructure. The performed analysis uses induction as research methods, which allows extending isolated special cases of symbol distortion to the generalized procedures for degrading the transmitted information quality; an analogy involving the consideration of similar mechanisms for modifying data in a stream of modulated signals with one carrier and multiple ones. The novelty of the findings obtained consists in generalizing the process of decoding errors due to noise bursts to the systems with one carrier and several ones, as well as in differentiating the influence of the noise pulse duration and power on the transmitted symbols. As the main findings of the work, we can note the identification of the impact ambiguity of impulse noise on the transmission systems of digital subscriber lines, expressed in the necessity to take into account while analyzing both the parameters of the noise itself and the type of modulation, and the energy and time relationships between the useful signal and noise. Thus, the work shows that the destructiveness degree of the impulse noise impact on the transmission system of a digital subscriber line is determined by several characteristics that should be taken into account when developing mechanisms for the protection against interference, or, conversely, to justify the inappropriateness of their use.

Wi-Fi for Affordable Broadband & 5G in Rural Areas

The importance of Internet in our lives today cannot be overemphasized. So much so that access to Internet has been declared a fundamental right of citizens in several countries such as Finland, Spain, and Greece [1]. In most of the developed countries, high-speed Internet connectivity is enabled through wired communication infrastructure such as Fiber-to-the-Home (FTTH) and Very high bit-rate Digital Subscriber Line (VDSL). Unfortunately, the situation is not particularly encouraging in developing countries due to non-availability of such a pervasive communication infrastructure. The difference in the fiber-deployed-to-population ratio across developed and developing countries further underscores this disparity; while this ratio is 1.2 in USA, it is barely 0.1 in India [2]. Owing to this inadequacy of fiber/DSL availability, cellular access technology has emerged as the primary broadband access mechanism in developing countries. However, the penetration of cellular network is limited in rural areas as its deployment becomes unviable due to challenges such as low average revenue per user, sparse population density, and intermittent availability of electricity. This situation leaves majority of the rural people unconnected thereby creating a massive rural urban digital divide. The next generation cellular system along with the use of unlicensed Wi-Fi Technology can bridge this divide if we overcome the above-mentioned challenges. However, since the Fifth Generation (5G) cellular technology has focus on requirements such as 10 Gbps data rate, 1 ms latency, and very high speed mobility, the problems of coverage and affordability are likely to persist, further widening the digital divide [3]. This article explains how Wi-Fi is being used for affordable high speed broadband in rural areas. A successfully implemented case study of Jharkhand state is also presented, and it can be adopted as reliable business model for 5G or 5G type services in rural areas [4].

Optimalisasi Keamanan Jaringan Menggunakan Metode Port Knocking Pada LAZIS Wahdah Jakarta

Abstract— Network security system is very important, because it relates to the security of resources in network, if the networksecurity system is weak, so people are not interested could be easy to attacks on the system, either to manipulate the data or changing the configuration of the network . In Lazis Wahdah has not made the block on port network systems, and used of modem Asymmetric Digital Subscriber Line (ADSL) in the network do not block the port. This is because the ADSL Modem just can do simple configuration and also not have features such as Router. Focusing on the issue, the use of methods Port Knocking on Mikrotik RB951UI-2ND is an appropriate way to improve network security system. With Port Knocking only IP address that corresponds to the rule or according to a predetermined Knock can access Mikrotik, while that does not comply with the rule will remain blocked. So Port Knockingmethod can improve the security system on the network at Lazis Wahdah Jakarta. Intisari— Keamanan sistem jaringan sangat penting, karena berkaitan dengan keamanan sumber daya yang ada padajaringan berupa data-data, jika system keamanan jaringan lemah,maka orang yang tidak berkepentingan dapat denganmudah melakukan serangan pada sistem tersebut, baik untuk melakukan manipulasi data atau merubah konfigurasi padajaringan. Di Lazis Wahdah Jakarta belum melakukan blok pada port system jaringan, dan penggunaan modem AsymmetricDigital Subscriber Line (ADSL) pada jaringaan tidak melakukan blok terhadap port, ini karena Modem ADSL hanya bisamelakukan konfigurasi sederhana dan juga tidak memilik ifitur seperti halnya Router. Berfokus pada masalah tersebut,penggunaan metode Port Knocking pada Mikrotik RB941-2ND merupakan cara yang tepat untuk meningkatkan sistemkeamanan jaringan. Dengan Port Knocking hanya IP Address yang sesuai dengan rule atau sesuai dengan Knock yang telahditentukan yang dapat mengakses ke Mikrotik, sementara yang tidak sesuai dengan rule akan tetap diblok. Sehingga metodePort Knocking dapat meningkatkan system keamanan pada jaringan Lazis Wahdah Jakarta.

Determining of Optimal Telemedicine Communication Technologies with Regards to Network Interactive Modes: A Delphi Survey

Introduction: Different communication services with varying bandwidth are used to send information in the form of telemedicine technology. Bandwidth management, as defined in telemedicine technology, refers to using the desirable communication services according to the type of transaction and the information size to be transferred. Selection of communication services must be in such a way to result in minimum latency in the process of sending information and maintaining maximum cost-effectiveness.Material and Methods: This is an applied research which was conducted in 2019 by questionnaire survey amongst 60 participants, specialized in health information technology and medical informatics, who are working in hospitals and educational institutions of Tehran. Likert rating scale was used to quantify the research questions. Finally, by analyzing each weighted average, this study revealed the desirable communication services that correspond to the required transactions for deployment of telemedicine.Results: Transfer of multimedia information, using synchronized teleconferencing via primary low bandwidth technologies, had the lowest number average (0.96) and transmission of hybrid data (combination of picture, text, multimedia templates in synchronized or asynchronized modes) via Asymmetric Digital Subscriber Line (ADSL) technology had the highest average (4.96).Conclusion: Selection of communication services, with regard to its convergence with the information size and the type of their application, plays a significant role in controlling network traffic and preventing latency in the process of sending information in the context of telemedicine technology. High bandwidth communication services should be used for those telemedicine systems, which are offering services to many users, as well as those in which real-time transmission of information is essential. It needs to be pointed out that with regard to the cost-effectiveness of sending information, it is necessary to use low-cost services with low bandwidth for transfer of light weight information as well as for asynchronous applications in which latency in the process of information transfer is not detrimental.

A Hybrid Method to Reduce PAPR of OFDM to Support 5G Technology

The orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation scheme used for the transfer of multimedia data. Well-known systems like ADSL (asymmetric digital subscriber line) internet, wireless local area networks (LANs), long-term evolution (LTE), and 5G technologies use OFDM. The major limitation of OFDM is the high peak-to-average power ratio (PAPR). High PAPR lowers the power efficiency, thus impeding the implementation of OFDM. The PAPR problem is more significant in an uplink. A high peak-to-average power ratio (PAPR) occurs due to large envelope fluctuations in OFDM signal and requires a highly linear high-power amplifier (HPA). Power amplifiers with a large linear range are expensive, bulky, and difficult to manufacture. In order to reduce the PAPR, a hybrid technique is proposed in this chapter with repeated clipping and filtering (RCF) and precoding techniques. The proposed method is improving the PAPR as well as BER. Five types of pre-coding techniques are used and then compared with each other.

Impact of twisting rate in 10 pairs of unshielded twisted-pair copper cables on insertion loss and crosstalk coupling for G.fast technology

An ultrafast digital subscriber line (DSL) technology called G.fast is important for ultrafast broadband Internet access services. In G.fast, the existing cable bundles installed for 250 m from the distribution point to the customer’s premises are used to support the gigabit data transmission (aggregated 1 Gbit/s) for frequency up to 106 MHz or 212 MHz. Since unshielded cable is used, and the frequency is 12 times higher compared to the very high-speed DSL2 (VDSL2), it is important to investigate the cable performance in terms of insertion loss and crosstalk coupling. In this paper, the impact of cable twisting rate on 10 pairs of unshielded twisted-pair copper cables for a small copper bundle on insertion loss and crosstalk coupling is investigated. A simulation model is developed based on the standard cable installed in Malaysia. The model reliability is validated by comparing the obtained result with the published result in the literature. Besides, the twisting rate of 100 m cable is manipulated by changing its lay size to determine its impact on insertion loss and crosstalk coupling. The results showed that a high twisting rate can reduce the far-end crosstalk but increase both the insertion loss and near-end crosstalk.

Physical IC Design Layout of Memory-Based Real Fast Fourier Transform Architecture using 90nm Technology

In this paper we present a low complexity physical IC layout for memory based Real Fast Fourier Transform (RFFT) architecture using 90nm technology. FFT architectures are the most important algorithms in the modern communication systems like and very high bit rate digital subscriber line (VDSL) asymmetric digital subscriber line (ADSL). In this FFT algorithm is based on radix-2 decimation-in-frequency. In order to meet the real time requirements of very large scale integration (VLSI), we designed a low complexity and high speed FFT architecture. The RFFT architecture was realised using Verilog hardware description language (HDL). This architecture is simulated using Native code launch of cadence and synthesized using RTL code complier of cadence tool. Each step of application specific integrated circuit (ASIC) physical IC design flow was synthesized using cadence Innovus 90nm technology and we optimize the design to reduce the area, power and timing requirements

Comparing simulation model for objective QoE video evaluation with real IPTV test scenario during appearance of packet losses

The aim of this article is to explain benefits of the simulation model for objective QoE (Quality of Experience) video evaluation in order to find similarities with real IPTV (Internet Protocol TeleVision) system distribution in a DSL (Digital Subscriber Line) network. In DSL networks, it is known that packet losses appear suddenly and might have a "burst" character, at any time during IPTV service delivery. In addition, these packet losses usually appear in groups and lead to huge degradation of the IPTV video service, which decreases a customer's QoE guaranteed level. Hence, estimation of this degradation in an access network is crucial and this paper explains a simulation model based on SSIM (Structural Similarity Index) analysis, which can be used as one perceptive video quality assessment by imitating a real environment with packet losses. To check this, we compared simulation model cases with the real ones in IPTV video distributed over DSL and exposed to different packet loss appearances.