Communication systems

As networks grow both in importance and size, there is an increasing need for effective security monitors such as Network Intrusion Detection System to prevent such illicit accesses. Intrusion Detection Systems technology is an effective approach in dealing with the problems of network security. In this paper, we present an intrusion detection model based on hybrid fuzzy logic and neural network. The key idea is to take advantage of different classification abilities of fuzzy logic and neural network for intrusion detection system. The new model has ability to recognize an attack, to differentiate one attack from another i.e. classifying attack, and the most important, to detect new attacks with high detection rate and low false negative. Training and testing data were obtained from the Defense Advanced Research Projects Agency (DARPA) intrusion detection evaluation data set.

As part of the National Center for Border Security and Immigration (NCBSI) led by the University of Texas at El Paso (UTEP), researchers from the University of Washington, Wayne State University, and UTEP conducted a three-site study of border security operations and the role of command, control and communication (C3) systems in support of those operations. While inevitably bringing some positive capability to the environment, if C3 systems are not consciously aligned with desired practices and decision-making, the implications will not always be for the better. This is especially true of C3 systems in the border security environment because these systems are intimately intertwined with complex and critical workflow and decision-making processes, often in the context of complex and, at times, competing missions.

In many packet-based communication systems such as TCP/IP-based systems, packets are communicated over a noisy physical layer (a channel), and if a packet cannot be decoded correctly, then the transport layer retransmits it. Of course, retransmissions consume significant resources and their use should be limited. However, decreasing the likelihood of retransmission requires to encode the packets with strong channel codes in the physical layer, which also requires additional channel resources. In this paper, we study the cross-layer tradeoff between coding and packet retransmissions, and optimize over the total channel resource consumption. We show that as the packet length k increases, the redundancy r beyond the k/C channel uses implied by Shannon's channel capacity C is Theta(radickln(k)) extra channel uses. Moreover, as k increases we must use stronger channel codes. We then apply these results to universal coding over a piecewise memoryless channel with transitions between unknown i.i.d. statistics. Our constructive universal algorithm has redundancy r=O(k2/3radicln(k)) using packets of polynomially increasing lengths while accounting for possible packet drops caused by transitions in the statistics.

In wireless sensor networks, data encryption and channel coding are considered together for ensuring secure and robust communication. In order to achieve this purpose, we introduce a new joint scheme, namely 'Multilevel/Advanced Encryption Standard-Low Density Parity Check Coded-Continuous Phase Frequency Shift Keying (ML/AES-LDPCC-CPFSK)'. AES algorithm is the most powerful and widely used symmetric key cryptography in providing secure data transmission. LDPC codes have very large Euclidean distance and use iterative decoding algorithms. In this study, we have increased error performance employing multilevel structure to AES and LDPC. In all communications systems, phase discontinuities of modulated signals result in extra bandwidth requirements. CPFSK, which is a special type of continuous phase modulation, is a powerful solution for this problem. In this paper, we simulate error performance of ML/AES-LDPCC-CPFSK for regular LDPC codes. Simulation results are drawn for 4CPFSK, 8CPFSK and 16CPFSK over wireless cooperative sensor networks. Using this scheme, we are able to improve bit error performance, channel throughput, security level of communication and reduction in complexity compared with related schemes such as various turbo code structures.

https://www.ijert.org/implementation-of-internal-communication-to-develop-employee-loyalty

https://www.ijert.org/research/implementation-of-internal-communication-to-develop-employee-loyalty-IJERTV10IS030266.pdf

This study aimed to discover the internal communication implementation of PT BT in developing employee loyalty. This study was carried out using a descriptive qualitative study method through the case study approach. The data collection was conducted via interviews and observations. The study results revealed that the internal communication implemented by PT BT's HRD was by conducting monthly activities for employees to implement internal communication within the company. Non-conducive condition greatly affects employee performance, which results in productivity. What most determines the means in the company are the leaders and the systems that manage the company. The higher the comfort of working in the company, the more influential it is in creating a comfortable condition in the company because they are the ones who greatly affect the productivity of the company.Communication with employees was carried out in several ways, i.e., weekly briefing with the Sales and After Sales division by creating various communication forums using the Planning, Implementation, and Evaluation concept. The communication activity was conducted in person using a regularly held online media forum according to each division's schedule. Interactions created within the forum grow the sense of togetherness and loyalty for employees. Besides, the company created events to better implement internal communication by conducting internal and external events. If the event was general, all divisions were gathered and selected for the best of the best and was given rewards as an output, such as allowances.

This paper assesses the performance of dual header pulse interval modulation (DH-PIM) over indoor optical wireless systems. DH-PIM being anisochronous scheme offers a built-in symbol synchronization capability. Theoretical and simulation results demonstrate that DH-PIM offers shorter symbol length, improved transmission rate and bandwidth requirement and a comparable power spectral density profile compared with digital pulse interval modulation (DPIM) and pulse position modulation (PPM) schemes.

Base station antenna tilt is a powerful tuning parameter in traditional cellular network optimization. With the introduction of Self-Organizing Networks (SON), this parameter may now be used also in the context of self-optimization. One envisioned scenario is load balancing (LB), where the coverage shaping properties of the antenna radiation pattern can be used to control the cell borders. In this paper, a generalized framework for antenna tilt LB is presented and discussed. In order to assess the performance of antenna tilt as a tool for load balancing, simulations are performed to determine the effect of tilt angle, vertical beamwidth and handover offset. The results show that there is a direct relation between these parameters and the number of users that can be shifted towards neighboring cells. In conclusion, it is found that using antennas with narrow vertical beamwidths together with small hand over offsets is an efficient way of performing load balancing but results also in high SIR variations. CONCLUSION In this paper we discussed the process of antenna tilt load balancing and analyzed the impact of vertical beamwidth and handover offsets. A general framework on which antenna tilt LB can be introduced in mobile networks was presented, based on a centralized SON architecture. This approach does not require additional functionalities at the base station and it is based on standard performance reports, e.g. Call Blocking Rates (CBR), Call Dropping Rates (CDR). The definition of "cell load" and "resource" can be adapted depending on Radio Access Technology (RAT) to derive specific solutions. The efficiency of antenna tilt as a tool for LB is closely related to the vertical beamwidth of the antenna and also to the HO offset values between the congested cell and the neighbors. Narrow vertical beamwidths together with small HO offsets showed the best results in respect to the considered metric. On the other hand, LB using antennas with narrower vertical beamwidths also resulted in higher SIR variations.

The term wide area measurement system (WAMS) implies a system including new digital metering devices (e.g., phasor measurement unit) together with communication system which is designed for monitoring, operating, and controlling power systems. Generally, a WAMS process includes three main functions: data acquisition, data transmitting, and data processing performed by measurement devices, communication systems, and energy management systems, respectively. While these three functions are seriously interdependent, most researches carried out on this topic investigate these functions independently. In this paper, meters placement and their required communication infrastructure for state estimation program are co-optimized simultaneously. To perform this, these two planning issues are jointly formulated in a single genetic algorithm (GA) problem. Then, three IEEE test networks without any conventional measurements and communications are used to investigate the advantages of considering dependability of optimization of these two sections. The results confirm that the proposed method is advantageous over the techniques optimizing each section independently. The results indicate that while the total number of measurement devices for system observability may increase (and therefore, the observability is improved), the total cost for the plan is reduced. Index Terms-Communication link placement, meter placement, power system communication infrastructure, state estimation, wide area measurement system. I. INTRODUCTION W IDE AREA measurement system (WAMS) is a term introduced to the power system literature, recently. This term implicitly implies a system including new digital metering devices (e.g., phasor measurement unit) together with communication system which is designed to monitor, operate and control power systems in wide geographic area [1]. In general, a WAMS process includes three different interconnected functions [2]: data acquisition, data transmitting, and data processing. Measurement devices and communication systems together with energy management systems perform these functions.

A smart factory is an extremely digitalized and associated fabrication capability that depend on smart industrialized. the model of the smart factory is considered as new idea for the 4th manufacturing revolution. The major features for smart factory are perceptibility, communication and independence. Industrial unit have extended trusted on robotics. The GLOVA G7-DR20U is used as a programmable logic controller PLC for control the action of smart factory while using the NodeMcu esp8266 as the IOT board for communication between owner and the factory using the smart phone programming. The software programming in the mobile phone was written in MQTT program. The program which written inside PLC by using ladder language for controlling the work of PLC. The prototype of smart factory was containing from two motor one for horizontal movement while the other for vertical movement. The scheme moreover has six sensors. Every motor attach with double sensors to bound its movement. The other two sensors are one for detect the exist of production while the other for count the production in the output side. When running the system, it is shown that the system is working very well and the response to the communication system via IOT is very good also receiving and sending the information to the mobile phone without errors.

In this paper, we present a basis for treating, evaluating and measuring knowledge as an energy acquired by knowledge centric objects in society. The energy level acquired is indicated as their knowledge potential or KnP. Some objects get more charged in the knowledge domain and exhibit a longer and/or more intense energy trail. The Rate of knowledge acquisition, intellectual caliber and need intensity driving to acquire knowledge all play a role in the knowledge energy (Kenergy) thus acquired. Bounded by established principles of measurement, units, quantification and equations for dealing with knowledge, it becomes amenable to its own (knowledge) science with laws derived from the many disciplines and their own distinctive principles. We fall back on equations from thermodynamics, electrical engineering, fluid mechanics and transmission theory to quantify the flow-properties of knowledge. Though not completely precise and accurate at this stage of development in the science of kno...

Fear of security breaches has been a major reason for the business world's reluctance to embrace the Internet as a viable means of communication. A widely adopted solution consists of physically separating private networks from the rest of Internet using firewalls. This paper discusses the current cryptographic security measures available for the Internet infrastructure as an alternative to physical segregation. First the IPsec architecture including security protocols in the Internet Layer and the related key management proposals are introduced. The transport layer security protocol and security issues in the network control and management are then presented. The paper is addressed to readers with a basic understanding of common security mechanisms including encryption, authentication and key exchange techniques.

In recent years, several phenomena have caused significant pressures on the traditional, centralized urban structure. These phenomena include urban sprawl, separation of business and residential areas and concomitant dependence on transportation, the absence of effective or widespread mass transit, and declining oil reserves with rising energy costs. These conditions have made decentralization more attractive to many large organizations currently located in the central business districts (CBD's) of major urban areas. The increasing availability of sophisticated communications and computer technologies may encourage the continued growth and future decentralization of "information industries," thereby producing major urban changes. The telecommunicationsaugmented decentralization of a traditional, centralized organization to a diffused one with an intraorganizational telecommunications network is described. The key factors in this process are discussed: 1) the ability o...

The current 3GPP working assumption on the Evolved Universal Terrestrial Radio Access (E-UTRA) physical layer is that it will be based on single carrier frequency division multiple access (SC-FDMA) for the uplink and orthogonal frequency division multiple access (OFDMA) for the downlink. According to the concept specification, inter-cell interference mitigation techniques applicable to SC-FDMA and OFDMA systems are expected to be the key radio resource management techniques for E-UTRA. In this paper we propose and analyze a simple reuse partitioning technique (assuming coordinated subcarrier allocation in the cells) that is able to minimize intercell interference. We propose a model that is able to take into account that sessions dynamically enter and leave the system. Rigid sessions require a class-specific fixed number of subcarriers, while elastic sessions can enter the system if a minimum number of sub-carriers is allocated to them. In this rather general setting we analyze the system performance in terms of the expected number of sub-carrier collisions, the session blocking probabilities and the signal-to-noise-and-interference ratio performance. We present numerical results on the various trade-offs between these measures that provide insight into the behavior of OFDM based cellular systems and help dimension the parameters of a reuse partitioned system.

Mobility management is required to ensure the session continuity for multiple IP-enabled devices onboard a satellite that hands off between ground stations. Network Mobility (NEMO) can efficiently manage the mobility of multiple IP-enabled devices that are connected as a mobile network. However, existing mobility management solutions for satellite networks are unable to route through intermediate satellites links when a direct connection with a ground station is lost. We propose an architecture of NEMO in satellite networks with the routing through multiple satellite links using nesting where a mobile network connects to another mobile network. However, NEMO Basic Support Protocol (BSP) can be inefficient in satellite networks due to poor nesting formation leading to the routing loop, inefficient routes and overloaded links. We extend NEMO BSP for the efficient use in satellite networks by augmenting it with a decision criteria for the nesting. Results verify that the extended protocol ensures loop-free and continuous connection despite the loss of direct connection to the ground, and provides an insight on how to form the nested NEMO to avoid overloading. The architecture and the extended NEMO protocol can be used for the efficient and continuous transfer of data from satellite networks to the ground.

Reversible logic has attracted substantial interest due to its low power consumption which is the main concern of low power VLSI systems. In this paper, a novel 4x4 reversible gate called inventive gate has been introduced and using this gate 1-bit, 2-bit, 8-bit, 32-bit and n-bit group-based reversible comparator have been constructed with low value of reversible parameters. The MOS transistor realizations of 1-bit, 2-bit, and 8-bit of reversible comparator are also presented and finding power, delay and power delay product (PDP) with appropriate aspect ratio W/L. Novel inventive gate has the ability to use as an n-to-2n decoder. Different novel reversible circuit design style is compared with the existing ones. The relative results shows that the novel reversible gate wide utility, group-based reversible comparator outperforms the present style in terms of number of gates, garbage outputs and constant input.

Aiming at optimizing the use of a wireless sensor network (WSN) as a miniature components integrated on chip (according to SoC technology), the adoption of specific protocols in the fields of applications of such network type is crucial. WSNs differ largely from the traditional wireless networks, they consequently require the use of new variations of energy-preserving protocols to ensure a prolonged life span for a sensor and to allow autonomy for a mostly dynamic topology-characterized network. Indeed, several routing and medium access control (MAC) protocols were proposed, and often adapted to the targeted applicability (house automation, biology, security, rural…). In this paper, we put forward a layered model for WSNs, with reference to OSI, TCP/IP and IEEE802 models which guaranteed a simple design and an easy implementation, for computer networks on (LAN/Wi-LAN, WAN, PAN…), thanks to layer decomposition reducing complexity and outlining functionalities relating to layers/levels coordinating through specific interfaces. The suggested model defines the levels of abstraction features of a WSN nodes according to their types (sensor, base station "BS"…) and intelligence level so as to serve as a basic model for design and future implementations of WSNs protocols and applications. This layered model allows the interconnection of a WSN with any other type of computer network. .

We report on the subjective comparison of speech enhancement algorithms using the ITU-T P.835 standard. A Matlab toolbox, i.e. P835Tool, has been developed to comply with the ITU P.835 standard. The ITU-T P.835 methodology was designed to evaluate the speech quality along three dimensions: signal distortion, noise distortion and overall quality. The subjective comparison of five speech enhancement algorithms is presented. Results show the effectiveness of our developed toolbox for subjective comparison of speech enhancement algorithms. Furthermore, a new performance index based on subjective (ITU-T P.835) and objective (PESQ, ITU-T P.862) evaluations has been proposed.

Use of discontinuities in ground planes or in microstrip lines is currently employed to improve the performance of different passive circuits. It includes size reduction of amplifiers; enhancement of filter characteristics and applications to suppress harmonics in patch antennas. This paper presents an improved method of size reduction of a microstrip antenna using Defected Microstrip Structure. It does so by

Packet classification is an enabling technology for next generation network services and often the primary bottleneck in high-performance routers. The performance and capacity of many algorithms and classification devices, including TCAMs, depend upon properties of the filter set and query patterns. Despite the pressing need, no standard filter sets or performance evaluation tools are publicly available. In response to this problem, we present ClassBench, a suite of tools for benchmarking packet classification algorithms and devices. ClassBench includes a Filter Set Generator that produces synthetic filter sets that accurately model the characteristics of real filter sets. Along with varying the size of the filter sets, we provide high-level control over the composition of the filters in the resulting filter set. The tool suite also includes a Trace Generator that produces a sequence of packet headers to exercise packet classification algorithms with respect to a given filter set. Along with specifying the relative size of the trace, we provide a simple mechanism for controlling locality of reference. While we have already found ClassBench to be very useful in our own research, we seek to eliminate the significant access barriers to realistic test vectors for researchers and initiate a broader discussion to guide the refinement of the tools and codification of a formal benchmarking methodology. The ClassBench tools are publicly available at the following site:

In this paper a complete communication system simulation package is described, which includes digital as well as analog operations to be performed on the signal to be transmitted. The package simulates the transmitter, the communication channel, and the receiver.

International Journal of VLSI design & Communication Systems (VLSICS) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of VLSI Design & Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced VLSI Design & communication concepts and establishing new collaborations in these areas.

Authors are solicited to contribute to this journal by submitting articles that illustrate research results, projects, surveying works and industrial experiences that describe significant advances in the VLSI design & Communications.

The use of networks for communications between the electronic control units (ECU) of a vehicle in production cars dates from the beginning of the 1990s. The specific requirements of the different car domains have led to the development of a large number of automotive networks such as Local Interconnect Network, J1850, CAN, TTP/C, FlexRay, media-oriented system transport, IDB1394, etc. This paper first introduces the context of in-vehicle embedded systems and, in particular, the requirements imposed on the communication systems. Then, a comprehensive review of the most widely used automotive networks, as well as the emerging ones, is given. Next, the current efforts of the automotive industry on middleware technologies, which may be of great help in mastering the heterogeneity, are reviewed. Finally, we highlight future trends in the development of automotive communication systems.

The design and hardware implementation of a multi-carrier Gaussian minimum shift keying (GMSK) modulator, based on a direct digital synthesizer, suitable for global system for mobile (GSM) base station applications is described. The synthesizer does not only generate the baseband GMSK signal, but also delivers it at a low IF. Special care has been taken in order to minimize the required memory of the synthesizer. The hardware implementation is mainly based on a field programmable gate array device (FPGA) and a D/A converter. The number of carriers depends on the size of the FPGA. Finally, the hardware implementation of a two-carrier modulator is given.

This book describes the essential tools and techniques of statistical signal processing. At every stage theoretical ideas are linked to specific applications in communications and signal processing using a range of carefully chosen examples. The book begins with a development of basic probability, random objects, expectation, and second-order moment theory followed by a wide variety of examples of the most popular random process models and their basic uses and properties. Specific applications to the analysis of random signals and systems for communicating, estimating, detecting, modulating, and other processing of signals are interspersed throughout the book. Hundreds of homework problems are included and the book is ideal for graduate students of electrical engineering and applied mathematics. It is also a useful reference for researchers in signal processing and communications.

Wireless LANs have gone through rapid changes with respect to their security architecture in recent years. One view has been to incorporate WLANs under already existing VPN umbrellas and to view them merely as an alternative access method -thus preserving existing VPN infrastructure. Another view has been to address the security of the airwaves which has been demonstrated to be extremely vulnerable. The evolution of security standardisation based upon the work of the IEEE has evolved from WEP to WPA which introduced new key management and integrity mechanisms through to WAP2 (IEEE 802.11i) which maintains the management and integrity mechanisms of WPA but introduces AES encryption as well as moving much of the security functionality to the hardware. This paper traces the evolution and development of this new WLAN security architecture.

The need to secure information systems and networked infrastructures is now commonplace in most enterprises. The use of novel communication technologies has became a crucial factor that can considerably improve or affect productivity. This is essentially due to the importance of the information transmitted across communication networks and stored in servers. As a consequence, strong ties are being built between security and the enterprise business activity. Risk management, which is the discipline that deals with this aspect, integrates a litany of architectures, techniques, and models that are described in this paper. A global view is proposed to the reader through a presentation of the research activity that has been directed towards this field. sophisticated malicious acts. Such assertion is obviously wrong as the real weakness resides at the security planning level. Henceforth, structured methodologies that identify, analyse, and mitigate computer security risks have been evolved to help enterprises integrate security in their strategic plans. In fact, experience has shown that the appropriate application of a risk management (RM) approach would considerably limit the aforementioned losses.

TCP is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid-task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system to its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modeling and practical experiments; finally we propose and test one possible solution to resolve this performance bottleneck in Linux TCP.

Active optical networks Peer to Peer traffic Locality of traffic Power consumption and power efficiency a b s t r a c t Video streaming and video-on-demand are gaining popularity nowadays which dictates a need of bandwidth upgrade for Internet users. Many next generation optical access network architectures have been proposed to meet high capacity requirement on a peruser basis. However, the capacity upgrade in access networks, may lead to a huge traffic growth in the aggregation/core network. One way to avoid this problem is to keep the traffic locally (i.e., inside the access network area) as much as possible. It can be obtained by using locality-aware peer-to-peer (P2P) applications for content distribution and has the potential to offload the core segment. However, various optical access network architectures accommodate the P2P traffic in different ways. Thus, it is important to study these differences in order to identify the best architecture option for capacity offloading in the core network, energy efficiency and network resource utilization. By deploying a proper architecture in the access segment along with an efficient traffic locality aware strategy, the extra investment and capacity upgrade of the expensive core network resources needed to support the future traffic expansion can be minimized. However, to the best of our knowledge this kind of assessment is so far not available. Therefore, in this paper, we analyze the efficiency of supporting locality-aware P2P video distribution algorithm in three main types of optical access network architectures, i.e., active optical network (AON), wavelength division multiplexing passive optical network (WDM PON) and time/wavelength division multiplexing PON (TWDM PON). Our goal is to provide important design guidelines for the next generation broadband access architectures, while minimizing the need for the core network upgrade. We obtain this objective by utilizing the unique characteristics of each access network architecture in accommodating P2P video delivery applications. We have done an extensive literature study and for the first time we have compared performance of these architectures with respect to the amount of the traffic on the links in different aggregation levels, power consumption taking into account sleep mode functionality at the user premises, and required switching capacity in the nodes. Our results reveal that both active and passive architectures have good ability to localize P2P traffic, whereas they show distinct performance with respect to the other aforementioned aspects. This is caused by the different number of aggregation levels, link capacity, and resource allocation protocols. Considering the overall performance evaluation, it is shown that TWDM PON is the most promising option for the future broadband access, where locality-aware P2P video distribution is applied, thanks to its low energy consumption and required switching capacity of the network equipment needed to deliver this service. This conclusion is against the general intuition because of the PON's centralized control plane and passive

1. Consider a (7,4) code whose generator matrix is ...
(a) Find all the codewords of the code
(b) Find H, the parity-check matrix of the code
(c) Compute the syndrome for the received vector . Is this a valid code vector?
(d) What is the error-correcting capability of the code?
What is the error-detecting capability of the code?
2. Consider a systematic block code whose parity-check equations are where  are message digits and  are check digits:
(a) Find the generator matrix and the parity-check matrix for this code.
(b) How many errors can the code correct?
(c) Is the vector 10101010 a codeword?
(d) Is the vector 01011100 a codeword?
3. Consider the linear block code with the codeword defined by
(a) Show the generator matrix.
(b) Show the parity-check matrix.
(c) Find n, k, dmin;

The relatively less exploited terahertz band possesses great potential for a variety of important applications, including communication applications that would benefit from the enormous bandwidth within the terahertz spectrum. This paper overviews an approach toward terahertz applications based on SiGe heterojunction bipolar transistor (HBT) technology, focusing on broad-band communication applications. The design, characteristics, and reliability of SiGe HBTs exhibiting record of 375 GHz and associated max of 210 GHz are presented. The impact of device optimization on noise characteristics is described for both low-frequency and broad-band noise. Circuit implementations of SiGe technologies are demonstrated with selected circuit blocks for broad-band communication systems, including a 3.9-ps emitter coupled logic ring oscillator, a 100-GHz frequency divider, 40-GHz voltage-controlled oscillator, and a 70-Gb/s 4:1 multiplexer. With no visible limitation for further enhancement of device speed at hand, the march toward terahertz band with Si-based technology will continue for the foreseeable future. Index Terms-BiCMOS integrated circuits, communication systems, heterojunction bipolar transistors (HBTs), high-speed integrated circuits. N66001-02-C-8014. J.-S. Rieh was with the IBM Semiconductor Research and Development Center, Hopewell Junction, NY 12533 USA. He is now with the

5G networks will be the first generation to benefit from location information that is sufficiently precise to be leveraged in wireless network design and optimization. We argue that location information can aid in addressing several of the key challenges in 5G, complementary to existing and planned technological developments. These challenges include an increase in traffic and number of devices, robustness for mission-critical services, and a reduction in total energy consumption and latency. This paper gives a broad overview of the growing research area of location-aware communications across different layers of the protocol stack. We highlight several promising trends, tradeoffs, and pitfalls. I. 5G: INTRODUCTION AND CHALLENGES 5 G will be characterized by a wide variety of use cases, as well as orders-of-magnitude increases in mobile data volume per area, number of connected devices, and typical user data rate, all compared to current mobile communication systems [1]. To cope with these demands, a number of challenges must be addressed before 5G can be successfully deployed. These include the demand for extremely high data rates and much lower latencies, potentially down to 1 ms end-to-end for certain applications [2]. Moreover, scalability and reduction of signaling overhead must be accounted for, as well as minimization of (total) energy consumption to enable affordable cost for network operation. To fulfill these requirements in 5G, network densification is key, calling for a variety of coordination and cooperation techniques between various kinds of network elements in an ultra-dense heterogeneous network. Moreover, by implementing sharing and coexistence approaches, along with new multi-GHz frequency bands, spectrum efficiency can be improved. An overview of a number of disruptive technologies for 5G is provided in [1]. It is our vision that context information in general, and location information in particular, can complement both traditional and disruptive technologies in addressing several of the challenges in 5G networks. While location information was available in previous generations of cellular mobile radio systems, e.g., cell-ID positioning in 2G, timing-based positioning using communication-relevant synchronization signals in 3G, and additionally dedicated positioning reference signals in 4G, accuracy ranged from hundreds to tens of meters, rendering position information insufficiently precise for some communications operations. In 5G, for the first time, a majority of

The 12th volume of Tabula Imperii Byzantini deals with the historical geography of Eastern Thrace in Antiquity and the Middle Ages. Being the European hinterland of Constantinople, capital of the Byzantine empire for more than thousand years, the region was one of the most significant landscapes in the Eastern Mediterranean. Bordering on the Aegean in the west, the Sea of Marmara in the south and the Black Sea in the east, the area is exposed to different climatic influences and shows a notable regional variety. Prominent places of Eastern Thrace are Constantinople with its suburbs and the Bosphorus, Mount Ganos the "holy mountain" (Işıklar Dağı), the peninsula of Chersonēsos and the Istranca mountain with its numerous nameless fortresses. The introduction of the volume deals with geography and climate, with history, traffic-routes and economy. Furthermore, an alphabetical catalogue offers more than 700 entries of settlements, place-names, fortresses, churches etc. from late Antiquity and Byzantine times; it was composed by using GIS, written, archaeological and toponymical sources. The main map of Eastern Thrace is drawn to a scale of 1:800,000, a more detailed map shows the Golden Horn and the European shore of the Bosphorus to a scale of 1:100,000.

The word communication arises from the Latin word “commūnicāre”, which means “to share”. Communication is the basic step for the exchange of information.

For example, a baby in a cradle, communicates with a cry that she needs her mother. A cow moos loudly when it is in danger. A person communicates with the help of a language. Communication is the bridge to share.

Communication can be defined as the process of exchange of information through means such as words, actions, signs, etc., between two or more individuals.

Need for Communication
For any living being, while co-existing, there occurs the necessity of exchange of some information. Whenever a need for exchange of information arises, some means of communication should exist. While the means of communication, can be anything such as gestures, signs, symbols, or a language, the need for communication is inevitable.

Language and gestures play an important role in human communication, while sounds and actions are important for animal communication. However, when some message has to be conveyed, a communication has to be established.
What is a Signal?
Conveying an information by some means such as gestures, sounds, actions, etc., can be termed as signaling. Hence, a signal can be a source of energy which transmits some information. This signal helps to establish communication between a sender and a receiver.

An electrical impulse or an electromagnetic wave which travels a distance to convey a message, can be termed as a signal in communication systems.

Depending on their characteristics, signals are mainly classified into two types: Analog and Digital. Analog and Digital signals are further classified, as shown in the following figure.