6.1 Broadcasting · the PrTV-G which took effect on 01.08.2001. After tenders had been invited by...

6.1 Broadcasting

Broadcasting is regarded as the simultaneous distribution of information to a multitude of subscribers ("one to many"). In radio broadcasting the subscriber receives the information via an audio signal, whereas in television both an audio signal and a video signal are received. The further development in analogue radio broadcasting also allows to transmit additional data. Examples are RDS (Radio Data System) in radio broadcasting and broadcast videotex in television. The television standard used in many European countries is PAL ("Phase Alternation Line").

Broadcasting is characterised by the following three groups of functions:

Production: by means of sound and video recording, programmes are produced (news, movies, commercials etc.). Transmission: the appropriately processed signal is transmitted from the studio to the radio or TV user via different paths. This transmission can be carried out via terrestrial transmitters or satellite technology as well as by using cable networks. Reception: to make the distributed signals audible and/or visible, consumers need appropriate receivers, such as antenna systems, radio and TV sets as well as additional equipment (decoder, set-top box), if required.

Basically, three types of distribution can be distinguished in broadcasting:

Satellite broadcasting: the signals are distributed via broadcasting satellites.

Info-Box 28: Broadcast videotex

Broadcast videotex is digital information that is added to the analogue television picture. The page-oriented broadcast videotext is inserted in the gaps of the transmission of the picture sequences.

Info-Box 29: RDS

Radio Data System (RDS) uses a free space in the stereo multiplex signal at 57 kHz. The additional information is transmitted on an auxiliary carrier at a data rate of 1.2 kbit/s. RDS enables, among other things, automatic tuning to a selected station. The basic idea of RDS, i.e. to provide additional information for mobile reception, is continued in digital audio broadcasting.

Info-Box 30: Television standards

The PAL ("Phase Alternation Line") television standard delivers 625 lines at 25 frames (50 half-frames) per second, 576 of which carry picture information. Another television standard is, for example, NTSC. This television standard, which is widely used in the USA, delivers 525 lines at 30 frames per second.

In the broadcasting sector, digitisation has already arrived in many areas, such as in studio engineering, satellite transmission and, to a limited extent, also in the distribution via cable networks. Terrestrial transmission, on the other hand, is implemented in most European countries still according to analogue technology. However, there is no doubt that, because of the further development of communications technology that has been under way long since, digital transmission will be introduced probably in all European countries in the next few years, eventually replacing the analogue transmission links as from the second half of this decade.

On the part of the EU, for some time the year 2010 has been assumed to be the deadline for the final turn-off of the analogue frequencies. Only recently, on the occasion of the summit of the Council in Seville 2002, the action plan "eEurope 2005" was adopted, which stipulates, inter alia, that all member states will have to submit detailed time schedules for the switchover from analogue to digital transmission technology in the field of broadcasting.

Against the background of this European scenario, which has been developing for quite some time, the Austrian legislator laid down specific provisions under the heading of "digitisation" in section 6 of the PrTV-G which took effect on 01.08.2001. After tenders had been invited by the Federal Chancellor, the working group "Digital Platform Austria" was founded. Its central task is to support the regulatory authority in working out a digitisation plan, thereby involving all broadcasters and other affected market players.

The digitisation plan to be prepared shall guarantee a smooth transition from analogue to digital reception. In this process, all technical, economic and, also, legal framework conditions shall be taken into account or newly created. On the one hand, comparable measures (pilot trials or introduction of DVB-T) in other countries shall serve as benchmarks, on the other hand, it will be indispensable take account of the characteristics of the Austrian situation (dual broadcasting system only under construction, particular shortage of available frequencies, extremely mountainous country, fierce competition due to successful TV broadcasters from Germany etc.).

By means of a test operation various technical parameters shall be tested. In addition, it is intended to examine also the acceptance of new contents (applications) by the audience (additional offerings, data services, interactive applications).

Info-Box 34: Digital Platform Austria

"Digital Platform Austria" is a working group that was established by the Federal Chancellor. It supports KommAustria in working out a plan for the introduction of digital broadcasting in Austria.

These satellites orbit at a height of approx. 36,000 km above the equator, i.e. at the same speed as the earth; thus, the broadcasting satellites are "standing" still above a specific position on the earth. They receive a data signal from a ground radio station and, after amplifying or processing this signal, send it back to the earth. The coverage area thus achieved, also called "footprint", is much bigger, as compared to terrestrial coverage. Broadcasting satellites supply parts of continents or entire continents. In Austria, broadcasting programmes are received, in particular, via the ASTRA and EUTELSAT satellite systems. For this kind of reception, a satellite receiver ("dish") is required and, possibly, additional equipment, such as a set-top box. Furthermore, a decoder is required for decoding those TV programmes for which the broadcaster has not acquired the broadcasting rights for the entire coverage area. Terrestrial transmission: the signal is distributed via a large number of transmitters which are located at sites that are suitable in topographical respect and for radio transmission (similar to the mobile radio communications network). The terrestrially distributed signal is received by means of a room or house aerial. Cable broadcasting: the broadcasting signal is directly fed into a cable network. This method is similar to the distribution via a telephone network. Cable broadcasting is possible only in households that have a connection socket to the cable network. Cable networks are provided by different operators. In Austria, there are about 250 cable network operators. The largest Austrian cable network supplies more than 440,000 households in the capital of Vienna; however, a large number of cable networks only has a few hundred subscribers.

Frequency coordination (frequency management) is the process which is required to integrate a newly planned transmitter into an existing transmitter network. It has to be observed that national and internationally guaranteed rights are not violated and that no interferences are caused.

When the set-up of the broadcasting networks was started in the 1960’s and only few transmitters were operative, the coordination activities were easier insofar as enough frequencies (channels) were still

Info-Box 31: Service area

Service area: this is the area which is technically supplied (terrestrially or via satellite) with broadcasting signals by a transmitter. The terrestrial coverage area is defined by the location of the transmitter (topography), by the transmit power and/or the antenna characteristics of the system and, eventually, by the number and strength of the interference signals.

Info-Box 35: DAB and DVB

DAB (Digital Audio Broadcasting): this is a process developed and standardised by the EU research initiative EUREKA for the digital transmission of radio programmes. Besides improved sound quality, the digital transmission technology also allows to transmit additional information. So far, the DAB system has not gained acceptance to the extent expected.

DVB (Digital Video Broadcasting): this is an international standard for the digital transmission of TV and radio programmes, as well as various data services. DVB can be distributed via satellite (DVB-S), cable (DVB-C) or also via terrestrial transmitters (DVB-T). In addition to improved receive quality and the possible "taking along" of additional services, the more efficient usage of the frequency spectrum is an advantage of DVB.

Info-Box 36: Switchover

This term refers to the migration from analogue to digital broadcasting. Due to the shortage of frequencies, analogue and digital transmission in full configuration is not possible in parallel. Therefore, the digital transmission technology has to be set up step by step, while the analogue technology is being maintained (simulcast phase). Only when the highest possible degree of coverage by means of DVB-T has been reached, turn -off of analogue transmission can be considered. The simulcast operation will end with the switchover (also called ATO = Analogue Turn Off). In the simulcast phase consumers will be given the opportunity to replace their equipment (set-top boxes or digital TV sets) during reasonable periods of time.

Info-Box 37: Set-top box

This technical equipment allows to receive digital signals and make them visible on analogue TV receivers (DVB). The TV set itself can also assume the function of the set-top box, provided the required modules are integrated.

Info-Box 38: Conditional Access (CA)

Basically, "free to air" and "pay TV" are distinguished in the reception of broadcasts. "Free to air" reception means that any technically functioning receiver can present the broadcasting signal correctly. No additional charges are incurred, the signal is not encoded. In the case of "pay TV", there is a defined user group and only authorised users can present the received broadcasting signals correctly. The data stream, which is encoded before it is sent out, is decoded at the receiver by means of a smart card. Simultaneous decoding of several programmes (programme bouquet) depends on the content provider.

In summary, CA refers to commercial and technical system components that serve the purpose of making a signal visible and audible to those users who are given the corresponding authorisation by the programme provider (e.g. pay TV).

Info-Box 39: Programme bouquet

A programme bouquet is an arrangement of different programmes of one or several programme providers.

available for the transmitters to be newly planned. Because of the extreme density of today’s existing networks, coordination is extremely difficult, as almost no gaps can be found in the frequency spectrum any more, despite highly efficient technical methods. With regard to the utilisation of the frequency spectrum, we are approaching the limits of what is physically and technically feasible.

Broadcasting frequencies are a scarce resource, as more and more programme providers have to share a limited part of the frequency spectrum. It is not possible to expand the spectrum, since other radio services as well (mobile radio, military and public radio services, radio relay etc.) have to cope with the shortage of the share of the frequency spectrum allocated to them.

The entire coordination activities are based on international conventions and agreements on the European and worldwide levels. Special reference is made to the conferences on radio broadcasting in Geneva 1984 and on television in Stockholm 1961.

Info-Box 32: Channel

The TV frequency scale has different channel numbers (2 to 69). These channel numbers correspond to specific frequencies with associated bandwidths. The digital channel 34, for example, corresponds to a centre frequency of 578 MHz and a bandwidth of 8 MHz.

Info-Box 33: Transmission capacity

One technical definition of the term transmission capacity is limited to the parameters location, radiated power and frequency, such as Wien 1 - Kahlenberg, 500 kW, centre frequency of 578 MHz (channel 34).

Info-Box 40: EPG (Electronic Program Guide)/Navigator

A digital TV channel can transmit several programmes. Although this is an essential advantage, compared to analogue TV, it also creates a great number of programmes. The EGP/Navigator provides for orientation, with regard to the individual programmes, by offering additional information. In the set-top box, this additional information is separated from the programme contents again. So, the EGP, in a similar way as a programme journal, guides through the variety of programmes and provides background information.

Info-Box 41: MHP (Multimedia Home Platform)

The MHP system developed by European industry shall be used by all programme providers, terminal equipment manufacturers and network operators as uniform standard and common basis for interactive additional applications.

Info-Box 42: Multiplexing and Multiplexing Platform

Multiplexing: this term refers to the process, which is typical of digital transmission, where the different video, audio and data signals are compiled into a common data stream which is transmitted via satellite, cable or terrestrial antenna to the terminal equipment. In the digital TV set the received data stream is split up into its individual components again ("demultiplexing"). The term "multiplexer" refers to the actual technical device.

Multiplexing platform: this refers to the technical infrastructure for merging and distributing the programmes and additional services compiled in a digital data stream.

6.2 Telecommunications

6.2.1 Digital telecommunications systems

Irrespective of their embodiment, modern telecommunications systems operate "digitally". Messages, such as texts, pictures, speech or music, for example, are presented by sequences of the symbols "0" and "1"1 . The conversion of analogue messages into sequences of "0" and "1" is called "digitisation". The advantage of digital transmission is that the receiver of a message only has to identify where the transmitter communicated a "0" or a "1". This means - in complete contrast to analogue transmission, where every minute change in a transmitted signal carries some information – that small interferences are of no consequence, as long as the symbols "0" and "1" can be distinguished. Digital telecommunications systems therefore transmit messages with more reliability than analogue systems, and they can also be manufactured easily and at low costs with today's common production processes (VLSI technology).

The quality of a transmitted speech signal depends largely on the transmitted frequency range. For voice telephony services, only those frequency portions of an analogue speech signal are transmitted that are in the frequency range of 300 to 3,400 Hz (in comparison to that, the reproduction range of high-quality amplifiers and loudspeakers in the area of consumer electronics is within the frequency range of 20 to 20,000 Hz).

A deterioration in quality may also appear in case of digital transmission by (massive) interferences along the transmission path, as they occur time and again, in particular in mobile radio communications systems.

For (speech) connections, telephone networks today use a data rate of 64 kbit/s. This value is the result of the technical process, which is at the basis of digitisation. 8,000 times per second (every 125 micro-seconds) the current value of an analogue signal is measured ("scanned" by short pulses).

Each of these 8,000 values is then assigned to one of 256 value levels by means of a specific method, which includes the human physiological hearing perception. Each of these 256 value levels can be shown in technical form by an 8-bit number ("binary coding"). For a connection, 8,000 values of 8 bit each are ultimately transmitted every second (8,000 x 8 = 64,000 bit, or 64 kbit). This process is called "pulse code modulation" (PCM).

1 The Morse telegraph code uses the two symbols "dot" and "dash" to present all letters, numbers and relevant punctuation.

6.2.2 Circuit and packet switching

Today's switched networks in the area of voice telephony (in the fixed and the mobile network areas) operate according to the principle of "circuit switching". The characteristic features of circuit switching are the following: establishing a connection, the data transmission phase, and discontinuing a connection. When establishing a connection, the destination of the connection (and the type of connection) is indicated.

The "resources" reserved in a network in the course of establishing a connection (for example, the transmission capacities in all relevant transmission paths, as well as in the switching exchanges) will then remain as an exclusive right of access for the terminal systems of that connection until the end of the connection - even if no useful data is transmitted at a specific moment. The transmission path has been physically "connected through" between the two terminal systems, the useful data therefore needs no addressing information in order to reach its destination, but simply follows the established physical path.

A typical example of this would be the previously mentioned 8-bit speech data transmitted every 125 micro-seconds in the framework of a speech connection. However, this only applies to a user channel connection, in modern voice telephony networks the signalling data is transmitted separately in a separate signalling network (see section 6.2.4.1 ). The transmission method used here corresponds to the principle of a packet-switched datagram service.

Packet switching is characterised in that - for a connection - there is no exclusive reservation of transmission capacities along the different sub-sections between the terminal points.

The useful data is split up into packets, each of which is passed on from the terminal system to the network, together with their destination information. In case of packet switching, there are also connection-oriented and connectionless transmission variants within a network. In the case of the connection-oriented option, the path is determined only once in all switching exchanges when establishing the connection, on the basis of the information on their destination (target address). A logical connection number is allocated to the respective connection and transmitted to the terminal systems. During the transmission phase, the terminal systems will only forward the logical connection number in the individual data packets, which greatly simplifies the search for the path in the switching exchanges. In addition, the utilisation of the individual network nodes can be taken into consideration when establishing the connection, which is of benefit for the "quality of service" of a service (example of an application: ATM networks).

Contrary to that, in the case of connectionless packet switching, the terminal system will forward the complete target address with every data packet, which the switching exchanges will evaluate.

As no connection-specific data is stored in the different switching exchanges with this system (this is why one speaks of "connectionless"), it may also happen that subsequent data packets will take different paths in a network and will arrive in a different sequence at the receiver (example of an application: the Internet, which is based on the IP protocol).

6.2.3 Transport network (core network) and access network

Basically, two sub-areas are distinguished in telecommunications networks: the access network and the core network.

The control centres (switching exchanges, backbone routers, network nodes) and the associated - as a rule broadband – transmission paths must be classified as part of the core section of a network.

In the access section, the individual subscribers (terminal systems) are linked up by means of line transmission technologies or by means of radio communications. In both cases, concentrators (multiplexers) are used within the access network in order to be able to achieve a connection to the core network at favourable costs, once the traffic has been concentrated.

6.2.4 Telecommunications in fixed networks

Fixed network services are characterised by terminal equipment which is at a fixed location. It does not matter, in this connection, whether the data transmission to or from the subscriber is handled by means of line transmission technology or by means of radio communications.

In the access section of a fixed telecommunications network that has grown in the course of time, such as that of Telekom Austria, a copper wire pair ("twisted pair cable") is allocated to every subscriber. This twisted pair cable connects the subscriber's network socket to the nearest switching exchange in the core network of the network operator. The length of such a line varies from 10s of meters to several kilometres.

New network operators will also use alternative technologies in order to link customers to their network, given the costs of building one's own lines and when leaving aside the possibility of unbundling the subscriber lines of Telekom Austria2. One option in this connection is the WLL technology ("Wireless Local Loop"), where the distance between subscriber and the closest switching or concentrating exchange is bridged by radio technology.

Other options are to use the cable television networks or to use energy supply lines ("power line") - which was undergoing field-testing during the period under review.

The core section of a network consists of the individual switching exchanges and the transmission lines between the switching exchanges. The connections between the switching exchanges are often implemented as broadband glass fibre lines and with redundancy, so that natural disasters will not destroy the sub-connections and thus disturb the availability of telecommunications services.

While, as a rule, new network operators will only have few switching exchanges, on account of the still small number of their directly connected end-users, but also because of the use of modern access network systems that allow an economical link-up of subscribers from major distances, the opposite is true for the network of Telekom Austria for reasons of its historical development.

2 Operators of cable television networks do not know this problem, as telecommunications services may also be provided via

their hybrid glass fibre/coaxial networks. The electricity grid can also be used to provide telecommunications services. 6.2.4.1 Core network structure 6.2.4.2 Different types of subscriber lines 6.2.4.3 Data traffic – Internet access 6.2.4.4 Inter-network connections:

interconnection 6.2.4.5 Carrier network operators 6.2.4.6 Number portability 6.2.4.7 Unbundling 6.2.4.8 Bitstream access

6.2.4.1 Core network structure

Since early 2000, only computer-controlled switching exchanges that also have a digital switching array are used in Austria. The individual switching exchanges in a network are connected by means of 2 Mbit/s systems (PCM30). Within a PCM30 system, 30 voice and/or data connections (user channels) can be handled simultaneously, each having 64 kbit/s. In this connection, a time frame of 125 micro-seconds is divided into 32 time slots (two of these are used for special purposes and are not available for transmitting useful data). Within every time slot, one 8-bit value is transmitted 8,000 times every second.

The 2 Mbit/s systems between the network nodes of big switching networks should not be imagined to be independent individual systems with regard to their implementation. These fixed connections (which cannot be influenced by subscriber signalling) between the switching exchanges are implemented in the so-called transmission technology network which is below the switching network in the overall model. Modern long-distance transmission networks are based on SDH systems ("synchronous digital hierarchy") which, inter alia, use glass fibre lines as their physical medium. These glass fibres often connect the individual network nodes in a ring topology. For reasons of redundancy, two rings operating in opposite directions are typically used. As a rule, SDH systems also form the basis of ATM networks. The data rates of SDH systems are about 155 Mbit/s ("STM-1"), 622 Mbit/s ("STM-4" = 4 x STM-1) and 2488 Mbit/s ("STM-16" = 4 x STM-4). Via the so-called add/drop multiplexers the low bit-rate "transport units" (e.g. 64 kbit/s, 2 Mbit/s, 34 Mbit/s) are input to, or output from, the SDH system. In the transmission network there are software-controlled network nodes, which are called cross-connectors. They serve for the "semi-permanent" switching (not for specific connections) of paths in the transmission network by means of network management functions.

The switching array of a digital switching exchange serves to connect ("to put through") the incoming 64 kbit/s user channels to the outgoing 64 kbit/s user channels, as determined by the software control of the switching exchange. During switching, the physically used PCM30 system and/or the number of the used time slot may change ("space/time switching array").

The individual switching exchanges of Telekom Austria are not fully intermeshed (i.e. not every exchange is linked to all the others), but according to a hierarchical network structure. Occasionally, one still refers to three network levels: central switching exchanges (HVSt), network switching exchanges (NVSt) and local switching exchanges (OVSt). In the future, there will only be a distinction between central switching exchanges (without any connected subscribers) and subscriber switching exchanges. With a view to the future, the TKK interconnection arrangements have basically

There are subscriber modules for analogue subscriber lines (POTS) and digital ISDN lines. At present, there are more than a thousand UVSts in addition to about 200 switching centres ("main exchanges") in the Telekom Austria network.

A UVSt is controlled by the central switching computer by means of signalling along the 2 Mbit/s systems. The main task of a UVSt is to concentrate traffic - in addition to analogue/digital conversion in the case of POTS. Traffic concentration means that the number of user channels between one UVSt and the attached subscribers (in case of POTS one channel per line, in case of ISDN two or 30 channels per line) is much higher than the number of channels between the UVSt and the switching exchange. It is therefore impossible for all subscribers to make calls at the same time. In practice, this is no problem. On the basis of the "traffic intensity" (average frequency/duration of calls) of the connected subscribers, the dimensions are structured according to the rules of "traffic theory" in such a way that the number of necessary 64 kbit/s user channels (or the number of 2 Mbit/s systems) between UVSt and switching exchange are kept at a minimum, without there being any noticeable constraint on subscribers. Difficulties may arise if the assumed traffic intensity, of several subscribers, suddenly goes up dramatically. The modem dial-up connections to the Internet are one subject that is being discussed intensively in this connection, since the traffic volume of individual subscribers may go up considerably, on account of the typically long connected periods - especially if the costs for such connections are very low or completely independent of use ("flat rate").

Within a switching network, one must distinguish between the user channel network and the signalling network. Whereas the user channel network serves to transport the useful data of the end-users (speech, data), the signalling network is used to exchange information between the switching exchanges - especially for controlling purposes when establishing or breaking a connection.

Just like the user channel network, the signalling network also uses the 64 kbit/s channels in the 2 Mbit/s systems to and/or from the switching exchange. However, whereas the user channel network always physically connects "joined" switching exchanges directly, the linking of switching exchanges in the signalling network is usually indirect.

To optimise the number of signalling connections between the switching exchanges, as well as the special hardware and software facilities required in the individual switching exchanges, the signalling channels of every switching exchange are typically only connected directly (failure protection) to two central transfer computers ("Signalling Transfer Points" - STP). As every message contains the address of the switching point at destination ("point

provided for only two levels from the very beginning (HVSt level - without directly linked -up subscribers - and the lower network (hierarchy) level as the level of the subscriber switching exchanges).

The core network of Telekom Austria comprises the special feature of the so-called "dependent" switching exchanges (UVSt) in the area of the subscriber switching exchanges. From a technical viewpoint, the UVSt is a component of a switching system that is operated at a different location than that of the switching exchange, with the switching of the system components being achieved by means of 2 Mbit/s transmission systems. By using UVSts the number of the expensive switching exchanges can be kept small, on the one hand, while the length of the subscriber lines can be limited, on the other. At the sites of the UVSts, the subscriber lines are linked at the so-called main distribution frame to the respective lines from the subscriber modules of the UVSts (without UVSts, the subscriber modules are used directly at the site of the switching centre).

codes" of the ITU Common Channel Signalling System No. 7), an STP can implement a correspondingly (transparent) forward transmission of the messages. In addition to the lower costs, the central function of the STP also promotes additional network monitoring functions, such as, for example, screening of the entire signalling traffic. Depending on the signalling volume, also several STP pairs may be implemented.

As already mentioned in the chapter on "circuit switching and packet switching", the process used in the ITU Common Channel Signalling System No. 7 (ZGV 7) for forwarding signalling messages corresponds to a datagram service, with the reliability of the technical components used in the signalling network of a classical voice telephony service being very high. Moreover, on account of the redundant double link-up of the switching centres to the STP pairs, the system is practically failure-safe.

6.2.4 Telecommunications in fixed networks 6.2.4.2 Different types of subscriber lines

6.2.4.3 Data traffic – Internet access 6.2.4.4 Inter-network connections:


6.2.4.2 Different types of subscriber lines

In the field of voice telephony, two types of lines are distinguished: "common" analogue lines ("Plain Old Telephone Service" - POTS), on the one hand, which account for about 90% of all lines in Austria, and the digital ISDN lines, on the other. In the case of ISDN lines, the analogue/digital conversion of voice already occurs in the terminal equipment, whereas in POTS lines the signals are transmitted in analogue form along the subscriber line, with the analogue/digital conversion only taking place in the switching exchange assigned to the line.

ISDN lines are offered in two versions: as ISDN basic access line (ISDN-BA) on the one hand, and as ISDN primary access line (ISDN-PRA) on the other. Basic access consists of two distinct user channels (B channels) at 64 kbit/s each, to transmit voice, fax or data, as well as a signalling channel (D channel) of 16 kbit/s which, inter alia, controls connection set-up. Basic access lines are primarily used by small and medium -sized enterprises, as well as private customers with more sophisticated demands, for example a voice connection is possible in parallel to an active Internet access. The primary access consists of 30 user channels (B channels), which are independent of one another, of 64 kbit/s each, as well as a signalling channel (D channel) of 64 kbit/s. The primary access line is used to supply big companies, which have their own PABXs, with voice telephony.

As the digitisation of switching exchanges has been completed since the beginning of 2000, a large number of service features is available to all POTS and ISDN subscribers, such as, for example, "Call Waiting", "Call Forwarding" or "Call Completion Busy Subscriber", with the services features of ISDN being more comprehensive on account of the signalling channel that is always available in parallel to the user channels.

Most recently, CLIP (Calling Line Identification Presentation), which is a common feature in ISDN and/or mobile networks, has now also been made available to POTS subscribers. It indicates the number of the caller to the called subscriber (whenever the available terminal equipment does not support this feature, a small additional unit can be used).

As was previously mentioned, the network of Telekom Austria used to rely on switching exchanges with analogue switching arrays and fewer end-user functionalities, as opposed to the "digital" switching networks of today. In the transition period, the expression "digital line" or "digital connection" has unfortunately become common terminology for analogue lines to digital Telekom Austria switching exchanges, which is not correct technically speaking and sometimes leads to misunderstandings. As described above, this term, technically speaking, only applies to ISDN lines. In the case of POTS lines, where additional new systems are implemented in the frequency range above the analogue voice signal (e.g. ADSL), the (use of a) line consists of an analogue and a digital component. The latter, however, is connected to a separate data network, upstream from the subscriber switching exchange - from the perspective of the voice network this continues to be an "analogue line".

6.2.4 Telecommunications in fixed networks 6.2.4.3 Data traffic – Internet access 6.2.4.1 Core network structure 6.2.4.4 Inter-network connections:


6.2.4.3 Data traffic – Internet access

In the near future, the area of fixed network services will experience a major change, as classical voice telephony is stagnating, while data traffic, especially on account of the Internet boom with the ever larger number of attractive Internet services (www, e-mail, FTP, Newsgroups, VoIP, etc.) is growing vigorously. This trend is even further enhanced by the up-and-coming "e-commerce". One of the consequences of increased (private) Internet usage in the evening, which in many cases occurs via dial-up modems, is that the so-called "rush hour", i.e. that hour in the course of a day when most traffic can be observed, on an hourly average, is shifting from the classical mid-morning hour (10 - 11 hrs.) to the evening hours (approximately in the area of 19 to 20 hrs.).

Telecommunications providers offer their customers new high-bit-rate data services, in addition to the classical dial-up modem, where up to 56 kbit/s can be transmitted downstream, depending on the quality of the line. To some extent, this is done on the basis of alternative infrastructures, such as the network of the cable television operators (with the cables being adapted for bi-directional traffic).

Another technical variant, based on the telephone lines, is to implement high bit-rate DSL services (Digital Subscriber Line), the best-known of which is available on the market by the name of "ADSL" (Asymmetric Digital Subscriber Line). The term "asymmetric" refers to the different transmission rates in the downlink (to the subscriber, high bit-rate) and in the uplink (to the switching exchange, low bit-rate). The usefulness of this asymmetry, when used by private users, becomes apparent when looking at a typical Internet session, where the user keys in a few data and retrieves large data volumes from the Internet (to build up a new image or because the downloading of a 10-MB file has just been triggered).

The ADSL service may easily be conducted via an existing POTS or ISDN basic access, together with the existing subscriber line, since voice telephony (POTS, ISDN-BA) and the ADSL data service use disjunctive frequency bands (ADSL works in the higher frequency band).

The associated signals are divided at the customer's location by means of frequency filters ("splitter") and at the local connection exchange where there are also the ADSL modems. On the side of the switching exchange, the ADSL modems are implemented technically as so-called DSLAM (Digital Subscriber Line Access Multiplexer), where the data packets of the individual subscriber lines are compiled for further transmission (or where the packages are distributed in the direction of the subscribers). For the transport of the data packages from the DSLAM at the central distribution frame of the local exchange to the service provider (typically an Internet Service Provider) a separate data network is used (e.g. on the basis of ATM). In other words, the "classical" line-switched voice telephony network is not burdened with these data connections. In Austria, ADSL is currently offered with a downstream data rate of 512 kbit/s, which corresponds to about ten times the rate of a modern V.90/V.92 dial-up modem.

The V.90/V.92 dial-up modems and the ADSL service (upstream data rate - 64 kbit/s) are primarily of interest for private users and small companies. A special variant for business customers are ADSL accesses with upstream bit rates of up to 256 kbit/s, which are used for special applications. For large-account customers data services and the Internet access are normally implemented via leased lines ("dedicated lines"). Here, the provider makes available to the customer a fixed, pre-set data rate, on a permanent basis, between two geographically defined network termination points. The data rates of these leased lines range from a multiple of the ISDN B channel (64 kbit/s) at the lower end to 155 Mbit/s at the upper end of the service range.

6.2.4 Telecommunications in fixed networks 6.2.4.4 Inter-network connections:

interconnection 6.2.4.1 Core network structure 6.2.4.5 Carrier network operators 6.2.4.2 Different types of subscriber lines 6.2.4.6 Number portability

6.2.4.7 Unbundling 6.2.4.8 Bitstream access

6.2.4.4 Inter-network connections: interconnection

In order to facilitate the communication between subscribers in different national networks, the national networks must be connected to one another. Such national "interconnections" are implemented in a form that is technically analogous to that of the international connections, where the operators of different countries are connected to one another via the large switching exchanges ("international exchanges") of the respective networks, on the basis of the relevant technical standards 3 of ITU or ETSI, among others.

The networks of the different national network operators are connected to one another at defined locations that are called "Points of Interconnection" (PoI). The standard solution ("end of span" variant) for an interconnection between networks ("joining link") provides for an electric coupling by means of 2 Mbit/s transmission systems (PCM30) at the PoI. When interconnecting with the network of Telekom Austria, the latter will implement - as a rule – the interconnection link up to the specific PoI in the network of the interconnection partner. For network operators that have the necessary glass fibre infrastructure, an interconnection option on an optical level is also provided ("in span" variant).

With regard to the interconnection of two exchanges in different networks, one must also distinguish between the linkage on the level of the user channel and the signalling level. Here, the fundamental explanations in the general chapter on the core network apply. Concerning interconnection with the network of Telekom Austria in the signalling network, Telekom Austria uses two STP pairs, on account of the traffic volume. The STP Pair West with STPs in Salzburg and Graz, as well as the STP Pair East with STPs at Vienna-Arsenal and Vienna-Schillerplatz.

The recent enormous increases in traffic of the SMS services constitute a burden on the inter-network signalling network capacities. SMS messages between subscribers in different mobile networks are currently transited via the signalling network of Telekom Austria. The signalling network, which was basically designed for the transmission of intra-network messages to control the connections in the user channel network between exchanges, actually serves the SMS services as a combined user channel/signalling network. The corresponding capacity demand is difficult to calculate - if necessary a direct interconnection of the mobile networks would provide a remedy in this context.

Below, the fundamental routing mechanisms are briefly summarised. They are of relevance, last but not least, for various aspects in the field of interconnection.

Establishing a connection begins, as a rule, when the calling subscriber ("subscriber A") dials the

Whereas it is ultimately a question of the subscriber’s terminal equipment configuration in the case of ISDN, en-bloc dialling is used, as a matter of principle, for (GSM) mobile radio communications, in order to use more efficiently the scarce resource radio channel - after dialling all digits, the en -bloc sending is triggered, as is known, by pushing the "dial" button on the mobile phone.

At the first switching exchange ("subscriber switching exchange") the incoming dialled digits are evaluated. If it is clear, on account of the received digits, that the connection will leave the range of subscribers of the switching exchange, the connection (user channel) to the closest switching exchange is established, selected on the basis of the received dialled digits.

This is done by using the available 2 Mbit/s connecting lines, by means of the "Common Channel Signalling System No. 7" protocol. If necessary, a further connection is built up via several intermediate switching exchanges, in sub-steps from switching exchange to switching exchange. In the signalling messages the switching exchange, to which the user channel connection is built up, is always recorded as the destination. It should be mentioned that, when building up a connection, not only the signalling network (output capacity and computer capacity within the switching exchanges) is used, but the corresponding resources are also reserved in the lines and switching exchanges of the user channel network. If the connection is ultimately not established, for example, because the subscriber B is busy, then the entire path along the user channel is taken down in the opposite direction.

During the first phase of liberalisation, national interconnection with Telekom Austria was only possible at the central switching exchanges. Now, this is increasingly also handled by the local switching exchanges ("lower network level"). This makes it possible for new network operators to forward telephony traffic into the network of Telekom Austria close to the destination (i.e. close to the dialled subscriber), or to accept incoming traffic from the (carrier) network of Telekom Austria close to its origin. The consequence are correspondingly lower interconnection fees. This, in turn, has a positive effect on end-users, as telephone rates go down.

At the end of 2000, Telekom Austria presented an expansion programme regarding the interconnection points on a lower network level and the accessibility of all Austrian local networks. In the final expansion stage, i.e. at the end of the first quarter 2002, about 40 switching exchanges will cover all local networks. At the end of the period under review, approximately 90% of these switching exchanges had been adapted for interconnection, and almost 80% of all Austrian

individual digits of a telephone number (number of "subscriber B"). This dialling may be in the form of an independent transmission of the digits to the subscriber line ("overlap sending") or by the transmission of the complete call number as one message ("en -bloc sending"). A technical requirement for the latter is that there be a distinct data channel between the terminal equipment and the exchange, as it is the case with ISDN, for example, or in digital mobile radio communications.

subscribers could be reached on a lower network level by means of interconnection.

3 The major communications protocol for the interconnection of international and national networks is the ITU Common

Channel Signalling System No. 7

6.2.4 Telecommunications in fixed networks 6.2.4.5 Carrier network operators6.2.4.1 Core network structure 6.2.4.6 Number portability6.2.4.2 Different types of subscriber lines 6.2.4.7 Unbundling6.2.4.3 Data traffic – Internet access 6.2.4.8 Bitstream access

6.2.4.5 Carrier network operators

If a fixed network subscriber of Telekom Austria wishes to make, and pay for, his calls via one of the new network operators, although the new network operator did not connect this subscriber line to his network, the customer only needs to dial the combination of digits "10xx" before dialling the desired number at destination (always with the local network area code, just as when making calls from a mobile phone). The two-digit code "xx" always clearly identifies the desired operator. What is needed beforehand is an agreement with the respective operator, who acts as "carrier network operator" in this case (in the variant operator selection/carrier selection or "call by call"). Telekom Austria forwards the call from the selected carrier network operator ("origination") and sets up the connection to the requested destination ("termination" in the target network). During the first semester 2000, "carrier pre-selection" was introduced in Austria as an additional pre-selection process. This is an alternative to dialling "10xx" for every call, enhancing the convenience of end-users. Previously, this had only been possible by using so-called "routers" (an additional piece of equipment that is interconnected between the telephone and the network termination socket and that automatically adds the "10xx" before the sequence of numbers dialled by the subscribers).

In the case of carrier pre-selection, a note is entered into the relevant subscriber connection data of a Telekom Austria subscriber at the relevant subscriber switching exchange that all connections are to be routed to the "pre-set" carrier network operator. It is always very easy to override a pre-selection when making a new call (by dialling 1001). After removing carrier pre-selection it is possible to make the next call as though there were no active carrier pre-selection for this line.

For various reasons, carrier selection and carrier pre-selection is not effective for all target numbers. The entire series 1 (numbers in the public interest, e.g. emergency numbers) and all services numbers are exempt. In the latter case, the target network operator fixes a uniform end-user rate for all networks (together with the services provider). These are so-called "target-network-tariffed" services numbers.

Until year -end 2000 the Telekom Austria network, in its switching exchanges, did not allow for a differentiated treatment of calls to specific groups of numbers, depending on whether carrier selection or carrier pre-selection had been chosen for a call. The TKK ruled a different handling, for example, for the segments of numbers that were not covered by carrier (pre-)selection. Whereas, in the case of carrier pre-selection (which does not include these numbers), such calls are to be transmitted by Telekom Austria via its network, in the case of carrier selection, where a subscriber explicitly indicates for every connection that a specific call be handled via the indicated carrier network operator (and that the subscriber be invoiced only by that operator), the connection is not made, or the subscriber is informed accordingly by an announcement that the connection cannot be made.

Moreover, a configured carrier pre-selection for local calls (i.e. calls within the same local network) was only effective if the respective local network area code was also dialled. Since 01.01.2001, these technical constraints no longer apply. However, it is still not possible to handle certain specific number segments individually for (carrier) network operators, i.e. there are individual number segments where traffic is only forwarded to all or to none of the carrier network operators.

6.2.4 Telecommunications in fixed networks 6.2.4.6 Number portability 6.2.4.1 Core network structure 6.2.4.7 Unbundling 6.2.4.2 Different types of subscriber lines 6.2.4.8 Bitstream acess 6.2.4.3 Datenverkehr - Internetzugang 6.2.4.4 Inter-network connections: interconnection

6.2.4.6 Number portability

In connection with number portability, a distinction is made between

operator portability, geographical portability, services portability.

Operator portability means that a user can change the network operator by "taking along" the number used by him. In these cases, there is a transferring network (operator) and an accepting network (operator).

In the case of geographical portability, a user can take along a telephone number to another geographical location. This may (but need not) be connected to a change in operator (operator portability).

Services portability means that a telephone number can be taken along, although the service is changed. On the international level, there are already countries where a geographical number from the fixed network can be "taken along" to a mobile network (or vice versa). POTS and ISDN are not separate services in this connection, but different forms of the voice telephony service in the fixed network.

As the NVO provides only for portability in the fixed network, the following comments are limited to this sector. There are different types of implementation throughout the world. An essential distinguishing feature in this connection is where the porting information regarding a number is stored, and which networks may access it. Below follows a brief description of the basic variants.

The best solution, in terms of technology, is a process where the transferring (original) network is no longer involved in the switching and accounting processes of calls to the ported number, once the portability option has been implemented. Otherwise, the services quality continues to be influenced by the transferring network. This will cause problems whenever the transferring network no longer meets the technical standards or fails completely and permanently, in an extreme case on account of bankruptcy. The technical implementation of such a process requires that every subscriber network or carrier network always has up-to-date information on porting, and that the calls are forwarded directly to the accepting network. Whenever a transit network is involved, the necessary routing information has to be forwarded to it. When beginning to set up a connection, there is therefore the so-called "all call query", where the current target network for a selected number is retrieved from a database. A technically efficient implementation of this approach requires that an inter-network database exists.

In several European countries, there are network operator associations or companies, where - as a rule - the major network operators, at least, will be represented. These have implemented such central databases - often by commissioning third parties. Changes in the central database, which is controlled and documented by means of workflow applications, lead to updates in the routing-relevant data in the networks of the network operators involved (for example, an update of the routing data on an IN platform). The real-time access in the course of a current connection is therefore not in the central database but in the individual networks.

Unlike this technically sophisticated solution, onward routing is another possibility. Here, after porting, only the transferring network (here also called the anchor network) knows to which network the ported number must be currently assigned. In consequence, all connections are established via the anchor network, which adds special routing information upstream from the dialled number before forwarding a call. This information contains the current target network for the subsequent (transit) networks. After a further porting, the anchor network will keep its function, the first accepting network is no longer involved after porting. This solution was developed in Austria by the AK-TK and implemented as a technical basis in the relevant TKK procedures.

An intermediate step between the two variants described above is a method called "query on release" or "call drop back". In contrast to the "all call query", no check for a possible porting is made in the subscriber or carrier networks every time a connection is established, but only if the wish to be connected, which continues to be forwarded to the original (transferring) network, is rejected by it with a special "porting reference".

A special constellation after porting will exist if the subscriber of a network calls a number that was originally part of another network, but was then ported to the caller's own network. The routing of such a connection via the anchor network should be avoided, even though there may be a basic implementation of onward routing, so as to use the total network resources economically. In case of calls to services numbers, the TKK has imposed the obligation for such cases that the respective accepting network must recognise the situation and must handle the routing within its network. In case of calls to geographical numbers, Telekom Austria was not required to meet this obligation. Other arrangements were made instead, as Telekom Austria claimed technical problems, on account of the resulting high requirements on performance. For the other fixed network operators the aforementioned arrangement for services numbers also applies to geographical numbers.

6.2.4 Telecommunications in fixed networks 6.2.4.7 Unbundling 6.2.4.1 Core network structure 6.2.4.8 Bitstream access6.2.4.2 Different types of subscriber lines

6.2.4.3 Data traffic – Internet access 6.2.4.4 Inter-network connections: interconnection

6.2.4.5 Carrier network operators

6.2.4.7 Unbundling

In connection with unbundling, a distinction is made between

full unbundling (incl. the variant sub-loop unbundling) and shared use.

In the case of full unbundling, the full length of the copper wire pair from the subscriber to the switching exchange of Telekom Austria is given to the unbundling partner for his exclusive usage. In the case of sub-loop unbundling, this applies to sub-sections which, as a rule, extend from the subscriber to a certain point on the way to the switching exchange.

In the case of shared use, Telekom Austria and the unbundling partner will share the frequency range on the copper wire pair of the subscriber lines that has been technically prepared for use. Here, the unbundling partner gets the higher frequencies, Telekom Austria gets the lower frequencies, which are already used now for voice telephony transmission.

The following comments relate to the full or sub-loop unbundling, on which the unbundling proceedings that were conducted during the period under review focused. For a better understanding of the underlying technical processes, the line infrastructure in the subscriber area (local loop) in the network of Telekom Austria is briefly described below.

Although one speaks of a "subscriber line" or the "copper wire pair", a closer look reveals that there is no continuous double-wire line from a switching exchange to the end-user. Rather, the local loop consists of several electrically linked sub-sections. The part called line-technology network (which, in turn, consists of sections) leads from the switching exchange to the distribution frame in the building, where the so-called cabling inside the building begins, which is the final section of the subscriber line that leads to the telephone socket in the house or apartment of the end-user.

The line-technology network starts out with thick cables (e.g. 1200 paired), in the area of the switching exchanges, which then become thinner lines in a step-by-step process on their way to the distribution cabinet inside a specific building. One distinguishes between a rigid network and the switching network. In the rigid network, the cables are divided and put into sleeves in the ground, which does not allow for any changes at a later date. In the switching network, however, the cables are branched inside the distribution cabinets. Both, the lines of the (underground) cable on the side of the exchange and on the side of subscriber, are made accessible at a distribution rail. Connections can easily be made and modified between the two distribution rails ("patching"). One speaks of line branching and cable branching points. From the latter, the cable extends to the distribution cabinet

In the building of the switching exchange, the individual lines (wires) in the cables that come from the switching system and from the subscribers are made accessible in one distribution rail each. The distribution elements are mounted both horizontally and vertically. From the horizontal side of the main distribution frame (HVt), cables with plastic insulation extend to the subscriber connections at the exchange system. From the vertical side of the main distribution frame cables with plastic insulation extend to the sleeves' room in the basement, where the connection is made to the underground cables. The patching of the individual subscriber lines (local loop) is always between the vertical and the horizontal side of the HVt. Fig. 101 shows the possible connecting points all the way up to the end-user, beginning at the point where the cable is led into the building of the switching exchange.

In case of full unbundling, the local loop to be unbundled is led from the horizontal main distribution rail via a transfer cable to the transfer distribution frame. Here begins the responsibility of the unbundling partner. If the transfer distribution frame is in the building of Telekom Austria, this step is called collocation. If there is not enough room in the building, containers may be used that are set up on the premises of Telekom Austria (outdoor container) or in the immediate vicinity (street cabinet). One ultimate possibility is the so-called "passive extension", for example up to apartments or basement compartments in the immediate vicinity, which the unbundling partner rents.

The implementation of sub-loop unbundling is much more complex, from a technical viewpoint. In the framework of the present report the many different possible problems cannot be described, which may occur due to the construction or the structure of the respective switching exchange in a specific case. A central question is how the transfer to the unbundled section of the TASL (local loop) can be implemented at the switching point (line branching point, cable branching point, distribution cabinet in a building, distribution cabinet on a building floor) that the unbundling partner wishes to have, without affecting the remaining infrastructure of the Telekom Austria line. It may be said in general, though, that indoor sub-loop unbundling (i.e. the switching point in question is inside a building) is less complex, as a rule, than outdoor unbundling. Reference is made to an outdoor cable branching point by way of example, where - as a rule – a mechanical access (borehole) must first be provided for the patching cable or the cable of the unbundling partner, which should then be closed again as a connection and should be tight against humidity. Moreover, such distribution frames in the public sector will not always be in places where another distribution cabinet for the unbundling partner may be set up without problems. Another area of complex problems relates to the lightning and overvoltage protection, where existing protective measures must not be affected by unbundling. Practical experience to date shows that

inside the building. In big office or residential buildings, there will be additional distribution cabinets on every floor, before the final line section leads up to the subscriber's socket.

the sub-loop unbundling variant is of little practical significance (at present).

6.2.4 Telecommunications in fixed networks 6.2.4.8 Bitstream access6.2.4.1 Core network structure 6.2.4.2 Different types of subscriber lines 6.2.4.3 Data traffic – Internet access 6.2.4.4 Inter-network connections: interconnection

6.2.4.5 Carrier network operators 6.2.4.6 Number portability

6.2.4.8 Bitstream access

In the case of bitstream access, Telekom Austria makes available to other network operators, or ISPs, a continuous high bit-rate access from the subscriber to the established transfer points (at present, there are seven in Austria). An overview of the technical implementation was already given in the chapter on "Data traffic - Internet access". In contrast to the unbundling variant "shared use", the complete infrastructure up to the transfer point is owned by Telekom Austria in this case.

The available bit rates, the concentration factor in the data network, and other technical parameters are set by Telekom Austria. Here again, the non-discrimination rule applies, which means that Telekom Austria must offer to third parties all those facilities that it offers to its own ISP (Jet2Web Internet Services GmbH).

6.2.4 Telecommunications in fixed networks 6.2.4.1 Core network structure 6.2.4.2 Different types of subscriber lines 6.2.4.3 Data traffic – Internet access 6.2.4.4 Inter-network connections: interconnection

6.2.4.5 Carrier network operators 6.2.4.6 Number portability 6.2.4.7 Unbundling

6.2.5 Telecommunications in mobile networks

Mobile radio communications services are characterised in that the terminal equipment is not connected by means of cables but via radio to the telecommunications network and that it is possible to make mobile use of terminals. Services of this kind make it possible to reach subscribers at mobile user terminals ("mobiles") in the most diverse settings. For the transmission of speech and data between the user terminal and the telecommunications network different frequency ranges are used, depending on the mobile communications systems.

6.2.5.1 Private mobile radio communications systems

PMR (Professional Mobile Radio) systems use radio links to allow closed user groups to use mobile communications. Such PMR networks are typically operated by the users themselves (private trunked radio communications networks), for example, taxi companies or authorities.

Simple analogue FM voice radio systems are increasingly being replaced by digital trunked radio systems (e.g. TETRA). The modern systems make better use of the frequency resources and offer additional features. In particular, both speech and data can be transmitted.

In addition to the professional radio systems, there are cordless systems, such as the digital system DECT, which is designed for use at home or at the office. It uses defined frequency bands that are not assigned to any specific operator. In the case of DECT, the radio resources are managed by intelligent DECT terminals that will always select the best channel. In such systems, the radio connection is between the base station, which is plugged into the telephone outlet of the fixed network, and the mobile - cordless - telephone.

6.2.5.2 Public mobile radio communications

systems 6.2.5.3 GSM frequency channels 6.2.5.4 Frequency spectrum UMTS/IMT-2000

6.2.5.2 Public mobile radio communications systems

In addition to public trunked radio communications networks (PAMR, Public Access Mobile Radio, the European ETSI standard in the digital area is TETRA), which are used by companies or authorities, during the period under review the following public mobile radio communications networks were operative, or in preparation, in Austria:

four GSM networks (the networks of Mobilkom, T-Mobile, Connect and tele.ring) with digital voice transmission at the air interface); one mobile radio communications network (the D network of Mobilkom) with analogue speech transmission at the radio interface; this analogue network was closed down at the end of February 2002; six UMTS networks (the networks of Mobilkom, T-Mobile, Connect, Mannesmann, 3G Mobile and Hutchison) [in preparation].

Each of the operative networks has its own infrastructure, which covers the entire Austrian federal territory. Call connections within one network can therefore be implemented without having to resort to the services of other networks. In order to facilitate call connections to other networks, several switching exchanges to other fixed and/or mobile radio communications networks are interconnected directly or indirectly.

The infrastructure of a mobile radio communications system consist essentially of the following components:

Access network:

base stations (BTS - Base Transceiver Station) base station controllers (control units for groups of base stations) connections between these network components

Transport network (core network):

mobile switching centres (switching exchanges) connections between these network components

A typical mobile network operator operates both an access network (i.e. he uses radio frequencies) and a core network. Alternatively, a Mobile Virtual Network Operator (MVNO) only operates a core network, while the access network is provided by another network operator. Outgoing and incoming calls of a customer with a SIM card of the MVNO are always carried over the switching centres of the MVNO.

Several base station controllers, in turn, are connected and linked to the exchanges. Every GSM operator has about ten to 20 mobile switching centres (MSC). Databases (Home Location Registers, HLR) available in every mobile network know the approximate whereabouts of every subscriber. Incoming calls are signalled in the area where the subscriber is located ("location area").

A distinction is made between the Home Location Register (HLR), where the data on the whereabouts of the subscriber assigned to the MSC in question is stored, and the Visitor Location Register (VLR), where data for subscribers from other MSCs is stored. Whenever the "visitors" are subscribers of another network, they are called roaming subscribers (Roaming).

In Austria, at present roaming is only possible between networks in different countries. After the introduction of UMTS, it will be also possible to roam between UMTS and GSM networks (national roaming).

For public mobile radio communications systems - such as digital GSM - separate frequency ranges are laid down in the frequency usage plans. Parts of this frequency range will be allocated to mobile radio communications operators, who therefore have different frequency ranges at their exclusive disposal. The frequency ranges used for GSM are 900 MHz (GSM-900) or 1800 MHz (GSM-1800 - previously called DCS 1800). In addition to voice telephony, which forms the larger part by far of the generated traffic, operators offer circuit-switched data services at transmission rates of up to 9.6 kbit/s. The modern variant HSCSD (High Speed Circuit Switched Data which is offered in Austria by one operator) achieves up to 57.6 kbit/s with four trunked time slots.

The circuit-switched data services are increasingly being replaced by packet-switched data services (General Packet Radio Service, GPRS).

With GPRS, the radio channel is seized only when data is actively transmitted. Thus, the limited radio frequencies are used more efficiently. Billing can be carried out on the basis of the amount of data transmitted – regardless of the online time.

GPRS will also form the basis for the data transmission of UMTS, but at a significantly higher transmission rate (approx. 384 kbit/s) and shorter delay than with GSM. The rate of 2 Mbit/s that is often stated for UMTS, in practice, will not be found very often in the first generation.

In addition to GSM, which is widely distributed worldwide, several countries still operate mobile radio communications networks with analogue voice telephony at the air interface, such as the D network in Austria (900 MHz frequency range), which was closed down at the end of February

The connections between the aforementioned network components in the access or the core networks are implemented with the operator's own lines, leased lines or by means of radio relay.

In GSM as well as in the first two releases of UMTS (release 99 and release 4) voice will be transmitted by means of circuit-switching, release 5 will introduce Voice over IP (VoIP), using the Session Initialization Protocol (SIP).

The base stations consist of antennas that are mounted on masts or building roofs, and switching cabinets that contain the necessary technical transmission equipment. The connection to the mobile units is set up by means of radio transmission via the base stations. A base station has a range between approx. 100 metres and several tens of kilometres. In order to secure full coverage in Austria, one operator needs 2,000 to 3,000 base stations. In areas where an operator must handle a very big volume of traffic, i.e. in regions where there are many telephone calls, further base stations must be built, in addition to those basically required for coverage. These are often so-called micro cells, using very small antennas, which are mounted on buildings, only a few metres above the street level. Micro cells cover an area with a diameter of several hundred metres and are used in densely populated urban areas.

Several dozens of base stations each are linked to a base station controller, which is responsible for the logical control of these base stations. These connections are implemented by leased lines and via radio relay.

2002. These networks can be regarded as forerunners of GSM. They offered limited functionalities. For example, data transmission and short-message services (SMS) are available only within certain limits.

Satellite systems, such as INMARSAT, are also used for mobile communications. INMARSAT uses geo-stationary satellites at an altitude of about 36,000 km and facilitates communication to almost every place on earth. The radio connection is between the mobile unit, which is much bigger than a conventional GSM unit, and a satellite. The capacity, i. e. the number of subscribers per square kilometre that can be serviced, is much lower with satellite systems than with GSM. Low-orbit systems (LEO, MEO systems) are under development or have not been able to gain market acceptance (e.g. IRIDIUM, Globalstar).

Paging systems only make it possible to send a message to a subscriber. They are increasingly being replaced by GSM.

In addition to the aforementioned systems, which all may also be used by private as well as business customers, there are systems that are specifically adapted to the communications needs of companies and undertakings. These so-called trunked radio systems work similarly to GSM, but permit more comprehensive group communication and a very fast call set-up. The users of such systems will be, for example, the police, the fire brigade, ambulance services, construction businesses or taxi companies. The standard defined by ETSI for digital trunked radio systems is TETRA. TETRA uses frequency channels with a bandwidth of 25 kHz. So far, the individual organisations have built up their own trunked radio networks. In Austria, frequencies in the 400 MHz range are used for TETRA.

Fig. 102 gives an overview of the frequency bands for GSM-900, GSM-1800, DECT and UMTS:

6.2.5 Telecommunications in mobile networks 6.2.5.3 GSM frequency channels6.2.5.1 Private mobile radio communications systems

6.2.5.4 Frequency spectrum UMTS/IMT-2000

6.2.5.3 GSM frequency channels

A frequency channel always consists of a band with a width of 200 kHz from the uplink and downlink area. The frequency channels for the GSM 900 band are marked with the numbers 1 to 124 (beginning at the lower frequencies), as well as the numbers 512 to 885 for the GSM 1800 band and the numbers 975 to 1023 for the extension GSM band.

One frequency channel (protection channel) each is kept vacant between the individual frequency packets that are assigned to different operators to avoid mutual interferences between the networks.

In border areas, agreements between countries contain arrangements on preferred frequency regulations, in order to avoid any mutual interferences between GSM operators in neighbouring countries. Along the border between two states, the preferred frequency spectrum of one state will be a non-preferred frequency spectrum in the other state. The conditions for preferred frequencies and non-preferred frequencies are contained in CEPT recommendations T/R 20-08 and 22-07. A certain field-strength value must be maintained in the neighbouring state at a distance of 15 km from the border in connection with preferred frequencies. For non-preferred frequencies this value must be maintained directly at the border.

The use of non-preferred frequencies to supply border areas is therefore possible only to a very limited extent. An operator must therefore have a sufficient number of preferred frequencies in all border regions which he wishes to supply with his services.

6.2.5 Telecommunications in mobile networks 6.2.5.4 Frequency spectrum UMTS/IMT-2000 6.2.5.1 Private mobile radio communications systems

6.2.5.2 Public mobile radio communications systems

6.2.5.4 Frequency spectrum UMTS/IMT-2000

UMTS (Universal Mobile Telecommunications System) is the European contribution to IMT-2000, the worldwide mobile communications system of the third generation. Mobile radio communications systems of the first generation are analogue systems, such as the D network in Austria. GSM (Global System for Mobile Communications) is the most successful representative of mobile communications systems of the second generation. With more than 640 million subscribers (source: GSM Association, December 2001), GSM, which is standardised in Europe, has spread far beyond Europe.

UMTS/IMT-2000 is to be implemented as of the end of 2002. It shall offer data rates that go far beyond those of current mobile systems. As a result, mobile multimedia applications (integration of voice, image and data communications) will be implemented.

IMT-2000 consists of a terrestrial system and a satellite system. The satellite system will facilitate mobile communications especially in those places where a terrestrial coverage is not available. The activities on the European and national levels currently focus mainly on the terrestrial component. Moreover, the terrestrial component of UMTS is being discussed.

For Europe the frequency bands for UMTS/IMT-2000 are defined in the decisions ERC/DEC/(97)07 and ERC/DEC(99)25. For the terrestrial part of UMTS/IMT-2000 a total of 155 MHz have been set aside. Of these, the ranges 1920 to 1980 MHz as well as 2210 to 2170 MHz, i.e. 2 x 60 MHz, can be used as paired frequency bands, and the ranges 1900 to 1920 MHz as well as 2010 to 2020 MHz are reserved for "non -licensed" applications. The range 2010 to 2020 MHz is therefore not available for assignment to operators in states that are transposing the relevant ERC decision. This means that 145 MHz (2 x 60 MHz + 25 MHz) can be assigned to operators.

Probably, as from 2008, additional frequencies (UMTS extension bands) will be available in the 2.5 to 2.69 GHz range.

UMTS, like GSM, will offer speech and data services. However, UMTS allows for higher data rates and shorter delays due to the more advanced radio interface. WAP and i-mode are protocols which use the GPRS (General Packet Radio Service) data service. Messaging services like MMS (Multimedia Messaging Services) can be transmitted by means of such applications. As a further expansion of SMS (Short Message Service), which is intensively used today, MMS allows to send and receive sounds and images in "multimedia" e -mails.

IMT-2000 (International Mobile Telecommunications) is the worldwide mobile communications system of the third generation. The ITU is responsible for standardising IMT-2000. IMT-2000 will combine different mobile communications systems of the third generation in the framework of a family design. "Roaming" will, however, be possible between the different systems.

UMTS, the European contribution to IMT-2000, was standardised by ETSI, together with other standardising institutes in the framework of 3GPP (3rd Generation Partnership Project). In January 1998, ETSI took a decision regarding the radio interfaces for UMTS. The radio interface UTRA (UMTS Terrestrial Radio Access) comprises W-CDMA (Wideband Code Division Multiple Access) for operation in the FDD mode (Frequency Division Duplex) and TD-CDMA (Time Division Code Division Multiple Access) for operation in the TDD mode (Time Division Duplex). The data rates of UMTS are said to be 144 kbit/s, as a minimum, in rural areas, and 384 kbit/s in urban areas. The frequently mentioned data rate of 2 Mbit/s is a theoretical maximum value which will not be relevant in practice.

For both access methods (W-CDMA and TD-CDMA) the bandwidth taken up by a channel is approx. 5 MHz.

6.2.5 Telecommunications in mobile networks 6.2.5.1 Private mobile radio communications systems

6.2.5.2 Public mobile radio communications

systems 6.2.5.3 GSM frequency channels

6.2.6 Numbering and addressing

6.2.6.1 The structure of international and national numbers

To be able to set up a connection via telecommunications networks, the address of the destination is an indispensable prerequisite for being connected. In voice telephony networks, although data may be transmitted via these networks, this address is a number with a clear assignment in the worldwide network. On an international level, the structure of these numbers has been laid down by the ITU (Recommendation E.164). An international telephone number has a maximum of 15 digits (without the international prefix). It consists of the country code and the national number.

To indicate to the exchange that an international number will be dialled, a so-called international prefix must be put in front of the international number. This international prefix is "00" in the case of Austria, which is often symbolised by a "+" in front of the international number (e.g.: +43158058). The country code is assigned by the ITU and is "43" for Austria.

The structure of the national number is determined by the NVO.

The leading "0" (= national prefix) is not part of the area code according to the NVO, but it must always be dialled before the respective area code if the calling subscriber is in Austria. The area code and therefore the national prefix need not be dialled when calling geographical numbers, i.e. when calling a subscriber number that is connected to the same local network as that of the caller.

A national number consists of the area code, or the access code, and a subscriber number with a maximum of nine digits, or a selection code with a maximum of four digits in case of numbers in the public interest. Numbers to emergency services and, in particular, special numbers consist only of the relevant access code.

6.2.6.2 Geographical numbers and services

numbers 6.2.6.3 Allocation of numbers 6.2.6.4 Other addressing elements 6.2.6.5 ENUM

6.2.6.2 Geographical numbers and services numbers

The numbering plan laid down in the NVO has already been implemented, except for the numbers of public geographically oriented networks and a few other exceptions. As today's local network codes overlap with other number segments, these number segments can therefore only be assigned with certain restrictions.

In the field of public mobile networks, there are also numbers to paging networks, in addition to the generally known mobile networks (D and GSM networks).

A number for private networks makes it possible for companies with different locations to be reached at one single number.

Personal services are services that facilitate calls from one person to another person, independent of the place, the terminal equipment, the type of transmission (cable or wireless) and/or the chosen technology.

It is expected that this number segment will especially be used for convergent services between mobile and fixed networks.

The EVO stipulates that calls to freephone services must be free of charge for the caller. For services with regulated fee limits, the EVO requires that callers to a number in the segment "0810" must not be invoiced more than € 0.0727 and in the segment "0820" not more than € 0.1453.

The tariff for premium rate services may be fixed at any amount. For consumer protection reasons, the minute rate charged must be announced to the calling subscriber in the first ten seconds after the connection has been set up, in keeping with the EVO. This announcement has been free of charge for the caller since 01.01.2001.

6.2.6 Numbering and addressing 6.2.6.3 Allocation of numbers6.2.6.1 The structure of international and national numbers

6.2.6.4 Other addressing elements

6.2.6.5 ENUM

6.2.6.3 Allocation of numbers

All numbers (except emergency numbers and special numbers) are allocated by the regulatory authority, in order to ensure a fair distribution of the numbers that are only available within limits. The corresponding framework conditions were laid down by the National Telecommunications Authority in the NVO. Emergency numbers and "special numbers" are allocated directly by the National Telecommunications Authority.

6.2.6.4 Other addressing elements

Upon request by the National Telecommunications Authority, the regulatory authority also administers those addressing elements that are not visible to the subscriber, such as "routing numbers" and "National Signalling Point Codes" (NSPC). The routing numbers are used in connection with special services (e.g. number portability). An NSPC is used to address the switching exchanges of different operators and is used for inter-network signalling.

6.2.6 Numbering and addressing 6.2.6.5 ENUM 6.2.6.1 The structure of international and national numbers


6.2.6.5 ENUM

A subject that was increasingly being discussed in 2001 is ENUM. ENUM stands for TElephone Number to Universal Resource Locator Mapping and makes it possible to obtain access to a great number of communications services by using the existing Internet Domain Name System (DNS) via a conventional E.164 telephone number. For example, a subscriber can reach other ENUM users via services, such as e-mail, Instant Messaging, Voice over IP, mobile and fixed network telephony or on the www, simply by using an E.164 telephone number.

Mainly, this is also a step towards convergence, the connection of the classical telecom world with the Internet. On the web site of RTR-GmbH a great deal of detailed information is available on this subject.

6.2.6 Numbering and addressing 6.2.6.1 The structure of international and national numbers


6.2.6.3 Allocation of numbers 6.2.6.4 Other addressing elements

6.1 Broadcasting · the PrTV-G which took effect on 01.08.2001. After tenders had been invited by...

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