Wireline and Mobile Networks

In the PSTN the voice band transmission possible in the frequency band 3003400 Hz by the traditional technologies. The digital transmission and switching are spreading however users need access through cheap analogue sets. The analogue line interfaces and sets limit very often the capabilities of networks. The digital technologies like ISDN support functional developments as well. The integrated service means, that the whole system generally supports bearer and teleservices. The PSTN ISDN...

Literature

6.8.1 Atj r , Nemzeti Teleh z Strategia es Program 2000-2006. sszefoglal , Szerkesztette Gaspar Matyas, Telehaz Kht, 2000. (Passageway, National Telecottage Strategy and Program) 6.8.2 . Perspectives on Distance Education Telecentres Case Studies and Key Issues, Szerkesztettek Latchem, Colin, Walker, David, The Commonwealth of Learning, 2001., Vancouver, www.col.org 6.8.3 Community Teleservice Centres, CTSC International, 1994 (A nemzetk zi telehaz sz vetseg jelentese a vilag telehazair l)....

VSAT networks

VSAT networks are satellite private networks established by regional or global corporations for handling their data traffic, in some cases also voice traffic. Earlier, this requirement was met by the Intelsat Business Service (IBS), but in order to meet the increasing demand, Telecom General (USA) developed in 1979 their system designated VSAT, for serving hotel chains, banks, news agencies etc. At present, the VSAT designation is no longer referring to the manufacturer, and is generally...

The radio spectrum

The electromagnetic spectrum spreads over the frequency range from near zero to 1023 Hz. In this very wide band take place the radio waves and also the light. The radiospectrum is a part of the electromagnetic spectrum at which frequencies the waves can generated, radiated and received efficiently and therefore will be applicable for different radio services. The part of the electromagnetic spectrum below 3000 GHz concerns radio waves. The radio waves propagate of radiation from an antenna...

Signals on Analog Subscriber Loop

Traditionally the analog subscriber loop is a twisted pair of copper wires so this loop is suitable for transmission of voice band (300-3400 Hz), DC and out of band signalling. DC signalling Closing the loop initiated by off-hook of handset means the intention of user to start a call or other cases during the ringing signal means the intention of user to answer the incoming call. The on-hook the handset means the intention for ending the call. The pulse dialling means a special coding of...

Standardization of networks network equipment

There is a strong, worldwide tendency for description of the networks by their interfaces towards the outer world and not bothering with the devices used for realization of the services provided through the interfaces (black box). Of course, the services are considered together with their quality. The Hungarian regulation omitted already at the start the transmission, power supply, network management and cable TV equipment from the set of equipment submitted to an obligatory type approval...

System utilizing meteorite burst

Meteorites entering the atmosphere are glowing and producing an ionized band lasting from a few tenth of a second up to a few seconds at a hight of 80 to 120 km. Depending on the density of the charged particles, this burst will either scatter or reflect electromagnetic waves in the 40 to 100 MHz range, allowing communication to be established over distances of 400 to 2000 km 2.1.7.4 . This phenomenon was discovered in 1935, and later on, between 1950 and 1975, intensive development work has...

System based on tropospheric scattering

The troposphere is the lowest 10 km part of the atmosphere. The inhomogenities within the common beam volume of the transmit and receive antenna act as sources scattering the electromagnetic waves into all directions of space. Thus components will be generated establishing coupling between transmitter and receiver. Tropospheric links are based on this weak coupling mechanism 2.1.7.4 . The first troposcatter link has been put into operation in 1953. It follows from the geometry of the link that...

Atmospheric absorption and dispersion

If electromagnetic waves are propagating in media of low loss the effect of the medium can be characterized with a complex permittivity, imaginary part of which is significantly smaller than its real part. Loss due to the electrically neutral molecules of the air can be characterized like that and is usually negligible. Electrically asymmetrical molecules cause higher loss it is reasonable to characterize them more precisely. Of this type is the molecule of water vapor and also of several gases...

Traffic models

Traffic consists of single or multiple arrivals of discrete entities (packets, cells, etc.). It can be mathematically described by a point process. There are two characterizations of point processes by the counting processes or the interarrival time processes 3.3.1 . The counting process N(t) 0 is a continuous-time, nonnegative integer-valued stochastic process, where N(t) max n Tn < t is the number of arrivals in the interval (0,t . The interarrival time process is a real-valued random...

Languages for describing test suites TTCN2

TTCN (Tree and Tabular Combined Notation) was first published as a standard by the International Organization for Standardization (ISO) in 1992. Since then, it is more and more used by the big telecommunication vendors as well as the operators and test laboratories. The language is supported by a large variety of sophisticated tools such as test systems, editors, compiliers, syntax checkers and simulators. TTCN has been used successfully to specify tests mainly for conformance testing but it is...

Principle of regenerative repeaters

Regenerative Repeaters

The application of regenerative repeaters allows the transmission of digital signals over theoretically arbitrary distances. The method has originally been developed for the first PCM systems using cables with copper conductors, but the principle is even today generally applied in other transmission systems too, independently of the transmission medium and the bit rate 2.1.5.2 . In the following, the principle of regenerative repeaters will be described. The electrical or optical representation...

Integration on the basis of 3rd generation mobile networks

Vast majority of users are connecting today to the Internet by a wireline solutions but forecasts for the near future predict significant increase in the number of users connected via mobile networks. Mobile Internet access technologies as GPRS (see subchapter 4.9) and 3rd generation mobile networks (3G) like UMTS (Universal Mobile Telecommunication System, one of the European members of the IMT-2000 family) provide sufficient bandwidth and expected to boom during the next a few years. However,...

Terrestrial mobile networks

Andrea Schmitterer-Bausz, dr. (4.9.0.-3.), Karoly Fiala, dr. (4.9.3.), Gyula Simon, dr. (4.9.4-8.), authors Mobile communications is a general term to cover different mobile systems developed for various user needs and consequently providing different services. The common feature of mobile systems is to offer mobility, i.e. the freedom to move and stay in touch, though the extent of mobility depends on the system type. Mobile terminals have access to the network through the air interface, and...

Attenuation by moisture

Usually the attenuation caused by the rain is the main effect investigated. Usually only the rain rate R in millimeters of water per hour can be easily measured. A light drizzle corresponds to a rain rate of 0.25 mm h, light rain corresponds to R 1mm h, moderate rain to 4 mm h, heavy rain to 16 mm h, and cloud bursts up to many centimeters per hour. The drop-size distribution is a function of rain rate, with a greater concentration of large drops occuring for heavy rain. Marshal and Palmer...

Functional Model of Networks

During the functional modelling of the networks we group the tasks performed by them into hierarchical functional layers. The functional model of the electronic communication networks is not wider than the model of the infocommunication networks, as fewer types of network tasks are carried out in the broadcast communication networks than in the infocommunication networks. We can obtain the model of the infocommunication networks if we merge the different functional models of the computer...

Internet over satellite

Satellite communication proved to be successful when terrestrial solutions became cumbersome because of the long period and high cost of the installation. In the eighties, the satellite market was enlarged by the large-scale proliferation of VSAT systems. However, these have been profitable for large companies only because of the high price of terminals and of the transponder leasing in 2001, appr. half a million VSAT terminals operated worldwide, two-third of them in the USA. Recently, the...

A Transmission properties of symmetrical lines

In their application pairs are characterized by the image impedance Z (R + jwL) (G + jwC) 1 2 and by the image (propagation) constant y ( R + jwL).(G + jwC ) 1 2 ,where R, L, G and C are the loop resistance ohm km , inductance mH km , conductance 1 ohm.km and the effectiv capacitance nF km per unit length, while w is the angular frequency rad sec . The calculation of frequency characteristics of these primary parameters is complicated and hardly useful. Their qualitative behaviour can easily be...

Order of bits in data transmission

Another convention shall be the order of bits on the line. Seen from the frame level of communication the addresses, commands, responses and sequence numbers are transmitted (to the line) with the low-order bit first (for example, the first bit of the sequence number that is transmitted have the weight 20). The FCS, the frame checking sequence is transmitted to the line commencing with the coefficient of the highest term (bit position 16).(See ITU-T Recommendation X.25 and X.75) A facsimile...

Tools and technology applied in wireline transmission systems

In open wire cupper, bronze lines of 2 to 5 mm diameter are applied. Bronze represents a compromise for meeting simultaneously the requirements of low resistance and greatest possible tensile strength. The bronze wire has been fastened to insulators mounted on steel supports, attached to wooden poles. The nominal distance between poles is 50 m. The wires have been fastened with hang-down provided for taking into account temperature changes. The different pole arrangement can be seen on Figure...

Frame type frame structure and frame address in LAPB

The LAPB used in X.25 assumes a direct physical link betwen a single DTE and a single DCE, where frames are interchanged between the two. Each frame is either a command or a response Information type Information (I) frame is allways a command. Supervisory types Receive Ready (RR), Receive Not Ready (RNR) and Reject (REJ) frames may be commands or responses, Selective reject (SREJ) frame may only be a response. Unnumbered types Set Asynchronous Balanced Mode (SABM), Set Asynchronous Balanced...

Teleservices and Bearer Services

Teleservices are defined at the user interfaces but the bearer services at the network interfaces of the terminal equipment as can be seen in figure 5.3.1. teleservices are telecommunication services which provide full communication in between users according to the agreed protocol of network operators including the terminal equipment functions bearer services are telecommunication services providing the signal transmission capabilities in between network access points Fig 5.3.1 Definitions of...

Binary modulation systems

Signals of digital sources are virtually always binary (M 2) and wave shapes are very simple NRZ (Non Return to Zero) pulses. Thus a digital signal stream is composed of a sequence of high and low voltage levels. Level transition can occur only at instances t kT. It is reasonable to regard this sequence as an analog signal and apply one or an other of methods described in the previous section. This results in modulations described in the sequel. i. Binary Amplitude Shift Keying (ASK) Signal...

Classical encryption procedures

A variant of the Caesar cipher that is more difficult to decipher is simple substitution. This process replaces each letter of the input alphabet of the clear text by another letter of the output alphabet, always using the same output letter for an input letter and assigning each input letter to a different output letter. Since the number of possible output alphabets is extremely high, one is tempted to believe that the key space is infinite. However, most of those possibilities are equivalent...

Necessity and Conditions of the Interconnection

During the development of telecommunications technology, in one of the archetyps of telecommunications switched networks, in the telephone network, early demand had emerged for an opportunity to communicate with the subscribers of other telephone exchanges and vice versa. Later on, this demand had been expanded to the accessibility of the subscribers of larger territories such as other countries. That development has brought along the structuring of the networks the local networks incorporating...

Public encryption processes Des Aes Idea

Cryptography has traditionally been used by the military, the intelligence agencies, and diplomacy. All of these organizations are typically centralized. They usually set up an intelligence center entrusted with the task to select the encryption algorithm, develop and enforce the security policy, and organize the continuous generation and distribution of encryption keys. The users of the application are well-defined communication end points that form a closed network. Closed network a...

Hi

Figure 3.1.3 Double-stage link interconnection metal ensuring good contact. Economic aspects also demanded applying bridges with a small number of crossover points (10 or 20). Bridges mounted on one common mechanical frame with the attached marking magnets and bars are called together a crossbar switching device. Through multiplication of horizontal outputs of the bridge a matrix of arbitrary size can be produced, the common mechanical frame and designation does not affect the size of the...

Map

The MAP (Mobile Application Part) protocol is used for gathering the appropriate pieces of information to establish mobile calls and for the management of the mobility. The MAP uses transactions, so it is a typical user of the TCAP. The MAP can be functionally divided into several subprotocols. The B interface describes the connection of an MSC and a VLR, but since they are always implemented as one functional unit, it is not implemented in practice. The C interface specifies the messages...

Building up of the CATV Systems

The place of CATV network in the program transmission reference network is shown in Figure 4.8.1. The parts of reference network are international network, regional network and the national network. Inside of latest one are the broadcasting network and CATV network (head-end and distribution network). International and regional parts are only in extraordinarily large systems. CATV systems consist of head-end, distribution network and at its end house networks and subscribers' outlets. worked...

Structure of SDH networks

Principle building blocks of SDH SONET networks are the following. Single mode fibre (e.g. ITU-T G.652) for connecting the netework devices. In some cases, this is substituted by a multi-mode fibre or a copper cable, for spanning short distances. Regenerator for signal regeneration, amplification and parity control. ADM (Add and Drop Multiplexer) for branching lower bit rate containers (e.g. VC-4, VC-12) from a high bit rate sequence (e.g. STM1, 4 or 16). DXC (Digital Cross Conect) for digital...

Quality of service indicators [1133

According to the different QoS definitions, QoS is a non-quantitative term, but there are a lot of factors, characterizing QoS. The name of them is quality of service indicators or measures or determinant of QoS.They are measurable in objective way, with tools or, in subjective way, by customer opinion surveys. So, there are two groups of QoS indicators, objective and subjective ones. The objective measurements are performed generally by the service provider itself, hence these measures are...

Modulation in the optical domain

Optical frequency band differs in many aspects from the electrical band. Bandwidth of the transmission medium is by several orders of magnitudes higher. Nearly exclusively waveguide-bound links are applied, thus users don't interfere with each other. Mainly due to these two reasons virtually always binary transmission is applied. A further characteristic of the optical band makes plausible and virtually exclusive a special modulation method, not applied in the electrical domain intensity...

From Community Antenna Television Systems to Broadband Cable Networks

The history of program distribution on cable began long time ago and it started with the distribution of audio programs for subscribers. Hungarian examples are the so-called News on Telephone (Telefonhfrmondo in Hungarian) service and wire broadcasting system (WBS). The WBS was operated in the 1950s. The mass spreading of television (TV) sets, the increasing number of available TV channels for reception in a given place and the building of the new block of flats needed the application of...

Coaxial part of distribution network and its building elements

The coaxial part of distribution network is between optical node at the end of trunk and subscribers' outlets. Its active elements are two-way, broadband amplifiers with and without bridger as well as amplifiers of house network. Its passive elements are coaxial cable, splitters (power dividers), taps, attenuators, cable equalizers, filters, power inserters and subscribers' outlets. Requirements of ideal signal transmission for this section of transmission path are also free from linear...

Nmleml Interface

The composition of today's networks has contributed to the complexity of managing these networks. These networks are commonly composed of network elements provided by various vendors. The task of interoperability extends beyond the network element layer up to the management layers, to include interoperability between multi-vendor Element and Network Management Systems. Service Providers have also taken advantage of technological advancements in transport network equipment. It is not uncommon...

The MG1 queue

The queueing system with Poisson arrivals, general service time distributions and a single server M G 1 is a very important category in teletraffic theory. In this subsection we overview the major results related to this queueing system 1.7.1 , 1.7.2 , 1.7.3 , 1.7.4 . W waiting time in the queue T response time in the system Nq number of customers in the queue N number of customers in the system S service time The average waiting time and the number of customers in the queue for the M G 1...

The data connection layer

Basic functions of this layer are the regulation of the medium access and the hiding of the physical layer from before the upper layers transparency . The WLAN MAC protocols present new challenges as compared with conventional LAN protocols Ethernet, Token Ring . This is explained by the fact that multipath propagation is present in an indoor radio environment, so the field strength may drastsically change within small distances, and even fall below the required level. Another problem is...

Common channel signalling concept

The conventional channel-associated signalling systems are not suitable for the ISDN. The transmission of speech data and signalling requires different features from the transmission medium. In speech transmission, for a relatively long time, we have to transmit a lot of information in a strictly scheduled way 1-1 octet long samples in every 125 us . The signals do not require so strict scheduling, their information content is relatively small, and typically there is quite a lot of time between...

Leased Line Services

Leased line is composed of dedicated transmission circuits to use by a customer that provides for transparent transmission capacity between fixed network terminating points. It does not contain switching functions controlled by the user. Leased line service consists in the provision of transmission capacity in the backbone network, or between customer site and backbone network of the carrier. Leased line services are often used by other operators for their network build out. In another usual...

Atmospheric refraction

If we ignore special cases such as links between satellites, all radio path travel through the atmosphere. The lower part of the atmosphere, the troposphere has the main role in the refraction of the radio waves propagating through. Here the atmospheric gases have the concetration high enough to refract the radio waves from the straight line. This effect is caused by the spatial variation of the troposphere refractivity. The radio refractive index of the trophosphere is due to the molecular...

Statistical properties of video signals

When describing video as random processes one is encountered by long range dependence meaning that the correlation pattern is considerably high even in the case large time lags between the corresponding values of the video signal. One of the reasons for this behaviour is that there are repeated pixel patterns, which tend to appear in each frame. Therefore, video signals have a quasi-periodicity at the frame frequency. Some typical correlation's is shown by figure 1.2.7. Figure 1.2.7. Temporal...

FDDI and CDDI

The Fiber Distributed Data Interface FDDI is a 100-Mb s token-passing, dual-ring LAN using fiber-optic cable. FDDI is frequently used as high-speed backbone technology because of its support for high bandwidth and greater distances than copper. A new specification, called Copper Distributed Data Interface CDDI has emerged to provide 100-Mb s service over copper. CDDI is practically the implementation of the FDDI protocol over twisted-pair copper wire. FDDI uses a dual-ring architecture with...

PDH Plesyochronous Digital Hierarchy

Pdh Hierarchy

The following multiplexing methods are applied in PDH telephone networks. Plesiochronous nearly synchronous . The clock signals of individual network tools multiplexers are identical only within specified tolerance limits. Their phase relations are not defined as they are not synchronized in lack of a synchronizing network. Note that this applies only for higher hierarchical levels because the 64 kb s signals and the 2 Mb s frames are synchronized to each other. Typically, a single equipment is...

VPN Virtual Private Network Services

VPN virtual private network service is a network service for business customers, primarily for voice transmission and computer network applications. Nowadays it is used for combined voice and data applications as well. Private voice network service is a VPN made of private telephone branch exchange network and specialised to specific traffic distribution of the customer therefore its usage is cost-effective. Cost savings come from network provision over software based networking equipment...

Sccp

While the MTP is suitable to transmit signalling traffic between any two signalling points only of the same signalling network, the SCCP Signalling Connection Control Part is suitable to perform signalling between any two signalling points even of different signalling networks. What makes it possible The SCCP has the routing capability based not only on the CCSS7 point codes, but it can also use the Global Titles for routing. Global Titles are identifiers that are out of scope of the CCSS7 like...

Conditions of distance work

The technical background, the telecommunications devices, and adequate knowledge and skills for the use of those devices, with continuous further learning abilities and willingness are conditions for the spread of distance work, accepted by everybody. The technical requirement for distance work is a network relationship between the employer and employee, which is either established for this purpose, or exists independently from it, too. This network could be general Internet or intranet...

Power supply interface of telecommunications equipment

One basic condition of the implementation of a power supply system, which is optimal both from technical and economical points of view, is that the parameters of the power supply interfaces of the powered equipment shall be standardised or uniformed. The power supply interface is the common interface between two functional units, at which the power unit is connected to the telecommunications equipment. With the standardisation of the parameters of the power supply interface the compatibility...

References

5.6.1 ETSI EN 300 001 1998-10 Attachments to Public Switched Telephone Network PSTN General technical requirements for equipment connected to an analogue subscriber interface in the PSTN 5.6.2 ETSI EN 300 386 2000-03 Electromagnetic compatibility and Radio spectrum Matters ERM Telecommunication network equipment ElectroMagnetic Compatibility EMC requirements 5.6.3 ITU-T Recommendation K.20 Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltage and...

Powering of wire communication networks

In the traditional wire line telecommunication systems the individual customers are connected via metallic conductors cables to the nearest telephone exchange. The metallic conductor e.g. copper pair is used for telecommunications and for the transmission of signals necessary for the building up of the connections. The required energy is provided by the powering system installed within the exchanges, or the energy is supplied via the metallic network to the equipment to be powered. In this...

Layered modell of networks

Communication protocols developed as communications technologies grow and expand, became and should evolve to a more and more sophisticated form as a result of the prevalence of man-machine and machine-to-machine communication beyond the traditional man-to-man one. Open systems, like intercommunicating computers and similar intelligent data terminals need for data communication among them such sets and suits of communication protocols, which can serve or support all of the requirements of any...

Integrated mobile personal terminal

Some fifteen years ago the European businessman visiting the USA was shocked about the widespread usage of mobile phones in public places. Ten years ago having one here in Europe was a status symbol, five years ago the parents began to attach one to their kids making them connectable and today in numerous countries the penetration of mobile phones exceed that of the terrestrial. Listening to one anywhere except particular places or events and speaking to one if not too loudly is no more...

Data communication networks

In data networks data terminal equipment change data with other data terminal equipment or network devices. The rules governing data interchange between data terminal equipment and between terminals and networking devices are called communication protocols. In that sense computer networks are data communication networks. This section deals with data communication networks and concentrating on the problematic of the data link layer. Every data interchangein data communication networks are...

Regulation of quality of service [1135 [1138

The key questions related to the QoS regulation are the following character of the regulatory enviroment monopoly or competitive enviroment , determination of QoS indicator set, published by service providers, policy applied to the service provider, as he she does or does not perform the in case of new services, timeschedule of introducing QoS parameters, the method and steps of maintaining quality, by the service provider. In the era of monopoly, first of all in the 80-es there were two basic...

Tcap

For controlling the GSM calls, transactions are used. For the transactions there is no need to establish signalling connections, but the transactions must somehow be identified, and if a transaction has a request answer form as in most of the cases , then somehow it must be able to pair the proper messages. Among others, these are the tasks of the TCAP Transaction Capabilities Application Part protocol, that uses the UDT UnitData message of the connectionless service of the SCCP. The SCCP is...

GSM Supplementary Services

Calling Line Identification Presentation CLIP Calling Line Identification Restriction CLIR Connected Line Identification Presentation COLP Connected Line Identification Restriction COLR Call Forwarding Unconditional CFU Call Forwarding on Mobile Subscriber Busy CFB Call Forwarding on No Reply CFNRy Call Forwarding on Mobile Subscriber Not Reachable CFNRc Barring of All Outgoing Calls BAOC Barring of Outgoing International Calls BOIC Barring of All Incoming Calls BAIC Barring of Incoming Calls...

Optically terminated multiplexer OTM

The OTM is suitable for receiving and transmitting N independent digital pulse trains over N independent wavelengths. The OTM is connected via protocol specific transponders to the client layers. Usual client signals are shown in the Table. In the case of protocol independent transmission, the bit error rate cannot be monitored. Figure 2.1.5.7. Functional representation of an optically terminated multiplexer OTM Figure 2.1.5.7. Functional representation of an optically terminated multiplexer...

Structure of the ISUP signals

The functionality of most of the ISUP messages is similar to those of the channel associated signalling. The most important differences are the digital format and the wide parameter set. An illustration of the general format of an ISUP message can be seen on Figure 3.4.9. Each ISUP message contains the already mentioned routing label and a circuit identification code. The latter identifies the voice ISDN circuit the signal refers to. It is followed by the message type code. Each message may...

The generalized Benes formula

Consider a service system with unlimited buffer. Assume that the system is stationary so that 0 represents an arbitrary time instant. The server capacity is 1 unit work per unit of time. The complementary distribution of the amount of work in the system at time 0 can be computed 1.7.5 by P V0 gt x JP u gt x gt u du and V-u 0 , where t is defined by t A t -1, t gt 0, and A t is the amount of work arriving to the system in the interval -t,0 . The result covers all realizable queueing systems and...

Concept of network and service quality

One of the newest and most general definitions of quality, derived from ISO ISO 9000 2000 DIS was born in year 2000 the quality is ability of a set of inherent characteristics of a product, system or process to fulfil requirements of customers and other interested parties The product may be a traditional product or a service, too. The services are intangible, inseparable, perishable and variable. The differences between the products and services lay in their quality interpretations, too. The...