1 Access Networks Types of Access Networks - - continue: other types: Radio Access Networks, CATV – AN, exploitation of power lines in AN lecture No.5 and /09- w.t.

2 -radio broadcasting (LF, MF, HF), TV bands (VHF,UHF), bands of mobile teleph. networks, satellite lines, and finally tens of GHz for RR lines and broadband AN - exclusively radiowave networks (or with retransmission stations) or combination with cable lines -advantages:...., disadvantages Radio Access Networks - RAN -RITL – Radio In The Loop, and also other names (RLL- Radio Local Loop, WLL-Wireless Local Loop) - general properties of RLL - in standard- ETSI ETR 139

3 Type of deviding Types of radiocommunications BandwidthNarrow-bandWide-band Transmission direction Broadcasting - unidirectional Bidirectional communications SystemPoint-to-multipointPoit-to-point User mobility Fixed wireless (cordless) user line Mobile terminal Transmission media terrestrial Satellite (and others…) see also fig Other classification – according to: services provided (teleph., data,...) method of sharing of information capacity... modulation methods:... private and public Classification of radio wave media Tab

4 RLL Fig General RLL Reference Model. SS – switching system, BSC- Base Station Controller, BS – Base Station, RT- Radio termination, TE - Terminal equipment, IF – interfaces, OAM-Operation, Admin. and Maintenance functions, NMA-Network Management Agent

5 - possibilities of including of RITL into AN: - cordless telephone - wireless AN (RLL – Radio in the Local Loop) - mobile cellular network Fig Radio wave network in AN: a) cordless telephone (CT) with individual connection, b) cordless telephone with common connection c) mobile cellular network (MS – mobile station) RTTE CT RTTE BS MSBS Exchange Cell a) b) c) user circuit circuits trunk trunk TN

6 Fig RLL (radio relay link) - point-to-point connection Fig RLL in the transport part of AN Switching network SS Switching network

7 CT – Cordless telephone and DECT system - history: CT1, CT2, CT3....  DECT Fig General reference model of DECT system Fig : DECT architecture in Access network Legend: FRT-Fixed Radio Termination PRT- Portable Radio Termination Global networkLocal network Switching network cell 1 cell n cell 2 Application

8 DECT - continue - it is narrowband cordless access to public or private network - there exist also P-MP type of DECT and complex applications similarly to mobile networks - 3 generations - it is the base for UMTS

9 multipoint scheme named LMDS (Local Multipoint Distribution Systems) – fixed radiowave access – the alternative option to cable AN – there are cells, devided into the sectors operated from BS by means of radio termination, BS are connected to backbone network; mostly ATM technology, licenced bands (with guaranted QoS), without licence (so called general licence, WLAN); TDMA, FDMA and CDMA; unresistent to rain and vegetable disturbing MMDS – (Multichannel Multipoint Distribution System) – or „wireless cable“ – utilised e.g. for TV signal distribution (DVB-C) in bands 2-3 GHz, LOS condition (Line-Of-Sight) must be satisfy for perfect receiving WLAN (Wireles Local Area Network): - radiowave type - IR (infra-red) type -fixed AP (access point) connected to LAN (e.g. Ethernet) + end station (client = power adapter, transmitter, receiver, antenna, etc.), but there can be also ad- hoc network without support infrastructure (stations communicate straightaway - each with another) - standards IEEE , HIPERLAN, HomeRF:... Broadband access systems FWA (Fixed Wireless Access)

10 WiFi – wireless technology, WiFi Alliance corporate mark; - for more possibilities of interconnections and connection in the frame of LAN (WLAN) - standard IEEE b (the first utilized), 2.4 GHz band, disturbed by MW- ovens, cordless telephons and by Bluetooth; a – 5GHz – is not disturbed. (There are also other standards ) - unlicenced bands, for short distances (in the building or premise, up to 11 Mbps), (they say, that without obstacles up to tens of km; up to 54 Mbps), the longer distance the less data speed,... WiMAX – Worldwide Interoperability for Microwave Access – system of WiMAX Forum company, this company certificates anything with WiMAX mark - wireless broadband acces within the framework of the last mile, alternative possibility to cables and DSL systems - standard IEEE (latest ), transmission over the long distances, as similar technology as mobile telephony, licenc. and unlicenced spectrum -...

11 WPAN (Wireless Personal Area Network) - less reach than WLAN - as such technologies as Bluetooth, ZigBee, HomeRF :...

12 Mobile Communications Network Fig Mobile communications system - cellular architecture, frequence planning, frequences repetition Generations: 1. – analalogue. narrowband FM, only national systems, MHz 2G – GSM, narrowb.TDMA, afterwards broadband CDMA, upstream , down MHz 2.5G or GSM 2+ = GPRS EDGE – between GSM and IMT G - UMTS and others (IMT-2000), in the 2 nd phase IP supporting network (TCP/IP protocol, radio network UTRAN) “3.9 G” – LTE (Long Term Evolution) 4G - ? Access network Supporting network External systems

13 Mobile Communications Network - continue Fig GSM network architecture or see next page other BS other MSC BS public fixed network other BS BS- base station Legend:

14 Fig Functional scheme of GSM network Mobile Communications Network - continue

15 Fig GSM more detailed Mobile Communications Network - continue

16 GPRS (General Packet Radio Service) – mobile data service, accessible for GSM users (and for IS-136 mobil users) – for WAP services (Wireless Application Protocol), SMS, MMS and a www- access  „2,5G“ UMTS – Universal Mobile Telcom. System – 3G mobile system, W-CDMA, access to web pages and to other data services, up to 14 Mbps historical application: paging – unidirectional radio systems (transport of data only in the direct to TE)– for both smaller private, but also greater public areas

17 Fig One of possible ideas of 4G network architecture concept - interoperability of several types of radiowaves networks Mobile Communications Network - continue satellites cellular networks radio and TV broadcasting Support network WLAN WPAN WLL

18 Fig : Classification of RRL systems (Radio Relay Link) Radio-relay links - RRL - fixed access point + mostly also fixed user terminal (point-to-point) - data speeds from E1 (2Mbps) up to STM1(155Mbps), km, frequency bands and frequency channels, H/V polarizations of neighbour channels, QAM channel modulation according to link length system each-to- another purpose - portable - fixed

19 Tab. Frequency band for RRLs (point-to-poit) core networks – up to 11 GHz access networks – above 11 GHz notification

20 Tab. Bandwidths in RRLs and possible combinations of STM dig. streams Fig.: Example: RR channels in band 6U Digital streamBandwidthNuber of states - modulation XPIC – additional circuits for interference suppressing by utilizing different polarizations of waves of the same frequency

21 Fig Examples of shapes and dimensions of several satellites orbit types Satellite networks - advantages, disadvantages - VSAT technology(Very Small Aperture Terminal – for both narrowband and broadband data (Internet, VoIP a video) LEO: Argos, Orbcomm, Iridium, Teledesic, Globalstar, Skybridge GEO: Thuraya (, Inmarsat (maritime - communications), cca 36000km above equator

CATV in the role of access networks

23 specifications: - DVB-C dig. signal, MPEG-2 compress encoding, resp. MPEG-4 AVC (H.264) - 4 or 5 dig. channels in previous 1 analogue one  carrier is modulated by transport stream by means of QAM - central node – previously with distribution role – now is transformed for bidirectional transport (interactive services) – down MHz with 8 MHz per channel; up 5-65 MHz (in USA MHz / 5-42 MHz and 6 MHz channels) - possibility of POTS – the main station must be interconnected with PSTN (see the next figure) - needed modernization of whole network (several hierarchy level of network, amplifiers, optical sections, O/E convertors, freq. splitters,....) -comunications standards based on IP protocol (Ethernet-frames with variable word length, resp. ATM technology): DOCSIS - Data Over Cable Service Interface Specification = international standard for communications via CATV (DOCSIS 3.0) – is also for cabel modems DVB/DAVIC Euromodem – standard developed in Europe (by ETSI)

Fig Architecture of CATV- AN with optical network in the primary segment (primary level) splitter the components of distribution system see e.g. in: df splitter - user splitter (tap?) / coupler tap / coupler Main Station – there are antenna combiners, convertors, amplifiers, splitters distrib.node centr.office 2-way amplifier - user wall outlet splitter (or band separator) of down- and up- directions primary optical PON section aerial (antennas) system secondary – coaxial section

Fig Functional scheme of cable modem and its implemenation into network (it can be integrated in Set-Top-Box ) – upstream is realized by telephone line HF CATV modem MAC – Medium Access Controll telephone subscriber line return channel realization in the case of 1-directional CATV network 64/256-QAM demodulator, error correction interface (Ethernet, USB, PCI) control (CPU) splitter telephone modem CATV subscriber line

PLC - Power Line Communication - utilizing of power lines in the role of broadband AN -advantages: or: PDSL- Power DSL

27 -2-phase wires for providing of BB services - LF, HF filters - high security required Base unit HF LF HF LF LAN Internet 4 x 400 V customer User terminal customer kWh Power transformer station Fig Principle of using power network for broadband (BB) access

28 Tab : Frequence bands previously permited by european norm for communications BandFrequencies[kHz]Note 3 – 9Only for power contractors A9 – 95For power contractor, and with their agreement for customers B95 – 125For private pusposes of customers C125 – 140For customers – there is required the protocol about agreement D140 – 148,5Private purposes of customers -but – for PDSL – there are allowable bands up to tens MHz (the larger distance the less transported frequencies) - development in area e-m compatibility and mutual interferences of different tel-com systems and disturbing by power network (there are stated some treshold values… )

29 IPTV and Internet via convenience outlet (in the frame of home network)- architecture: - Internet connecting - router (or DSL modem) connected to both Internet and power network - adaptors of Powerline technology connected to outlets in residence (behind transformer station, in the same phase circuit) - in the reach of 10 1 m data speeds up to 200 Mbps - undesirable: overvoltage defence (protect) and filters (!)