Mobile Communications Wireless Telecommunication

Transcription

1 Mbile Cmmunicatins Wireless Telecmmunicatin Systems Generatin 1 (1G) Generatin 2 (2G) Generatin 2.5 (2.5G) Generatin 3 (3G) Generatin 4 (4G) TETRA Mbile Cmmunicatin Wireless Telecmmunicatin 1 Histry Mbile Cmmunicatin: transmissin f signals and messages between statins ti frm which h at least ne is mbile Ges back t the 1920 s: public wireless radi system perated by the train in Germany (Reichsbahn) 1946 first prtable mbile telephne in the US: 18kg, 8min. battery life 1957 first mbile telecmmuncatin ti system in Germany (nwadays called PLMTS stands fr Public Land Mbile Telecmmunicatins System) s called A-system, manually switched, 137 calling znes 1972 start f peratin f the B-System, autmatic switching, but separate phne number in each calling zne (i.e. ne had t knw wh is where, if that ne is t be called) Mbile Cmmunicatin Wireless Telecmmunicatin 2 Histry 1981 first analg cellular system with fixed number fr subscribers, autmatic ti handver between cells. NMT 450 in Scandinavia. This is smetimes called 1 st generatin (1G) C-Netz in Germany, analg, in peratin until wrk begins n a standard fr a pan-eurpean digital PLMTS which ffers new services (SMS, call frwarding, ) by Grup Speciale mbile (GSM) 1987 "Memrandum f Understanding" signed by 18 cuntries t deply GSM (nw Glbal System fr Mbile Cmmunicatin ). In 1988 the standards were taken ver by ETSI (Eurpean Telecmmunicatin Standards Institute). This is a system f the 2 nd Generatin (2G) 1992 first GSM netwrks in peratin 1993 ne millin subscribers t GSM Mbile Cmmunicatin Wireless Telecmmunicatin 3

2 Histry 1998 intrductin f GSM Wireless Applicatin Prtcl (WAP) 1999 HSCSD 2000 GPRS, Generatin 2.5 (2.5G) first peratin f a 3 rd Generatin (3G) netwrk in Eurpa (UMTS) in Austria 2006 NTT DCM starts 4 th Generatin (4G) trial netwrk in in Yksuka in Japan. Maximum transmissin rate 2,5 Gigabit pr Sekunde G trial netwrks with100 Gigabit/s at 10 km/h First 4G-Netwrks n the Basis f LTE (Lng Term Evlutin) in 2011 Mbile Cmmunicatin Wireless Telecmmunicatin 4 Main characteristics f different generatins Generatin 0 (0G): calling znes, n handver Generatin 1 (1G): analg, unifrm subscriber number, handver between cells Generatin 2 (2G): fully digital Generatin 2.5 (2.5G): data transmissin Generatin 3 (3G): brad band digitalit Generatin 4 (4G): all IP based, brad band, high speed Mbile Cmmunicatin Wireless Telecmmunicatin 5 Generatin 1 (1G) wasn t the beginning f mbile cmmunicatin, but the beginning i f cellular l with handver and raming between sme netwrk peratrs analg transmissin f user channels, mstly fr speech nly already digital signalling fr switching purpses n dminant standard: Nrdic Mbile Telephne NMT-450 und NMT-900 Ttal Access Cmmunicatin System (TACS), Japan, GB Advanced Mbile Phne Services (AMPS) in US C-Netz (Germany) Radicmm 2000 (France) Mbile Cmmunicatin Wireless Telecmmunicatin 6

3 Generatin 1 (1G) Example C-Netz (Germany) Technical features: speech and signalling is transmitted in parallel (in band) speech frm 300 t 3400 Hz dwnlink 461,30 t 465,74 MHz uplink 451,30 t 455,74 MHz duplex separatin10 MHz channel separatin 20 khz (222 channels) transmit pwer 5mW t 15W Mbile Cmmunicatin Wireless Telecmmunicatin 7 Generatin 1 (1G) cell radius 2km 20km cell arund base statin switching system Mbile Cmmunicatin Wireless Telecmmunicatin 8 Generatin 1 (1G) Sender divides speech signal int blcks f 12,5 ms cmpressin f the blcks results in extra time slts f 11ms 1,1 extra time slts are used t transmit signalling infrmatin, e.g. handver, Receiver separates signalling data frm speech and decmpresses the signal Mbile Cmmunicatin Wireless Telecmmunicatin 9

4 Generatin 1 (1G) Already in the first generatin the smallest part f the transmissin path is dne wireless air interface cellular user cre netwrk Handynutzern cre netwrk fixed netwrk gateway Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 10 Generatin 2 (2G) digital fr user traffics and signalling higher h capacity, wider spectrum than 1G hierarchical cell structure: Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 11 Generatin 2 (2G) Main standards Glbal System fr Mbile Cmmunicatin (GSM) Digital AMPS (D-AMPS) IS-95 Persnal Digital Cellular (PDC) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 12

5 Generatin 2 (2G) - GSM Glbal System fr Mbile Cmmunicatin (GSM) is the mst successful cellular system wrldwide, >80% market share 1988 first trials f GSM, 1991 first netwrk in peratin 1993 first millin 1993 first implementatins utside Eurpe (Australia, New Zeeland, Hngkng) 2011 apprx. 5 millin subscribers ( Cverage map ( Operatins in different bands, e.g. 450MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, Raming cntracts between peratrs result in a single wrld wide netwrk Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 13 Generatin 2 (2G) - GSM Cverage by China Mbile surce: GSM Assciatin Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 14 Generatin 2 (2G) - GSM Cverage by AT&T Mbile surce: GSM Assciatin Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 15

6 Generatin 2 (2G) - GSM Cverage by Radimvil (Mexic) surce: GSM Assciatin Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 16 Generatin 2 (2G) - GSM Cverage by E-Plus (Germany) surce: GSM Assciatin Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 17 Generatin 2 (2G) GSM system architecture VLR HLR BSC BTS (G)MSC Cre Netwrk (CN) fixed netwrk, Base Statin Subsystem (BSS) = Radi Access Netwrk (RAN) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 18

7 Generatin 2 (2G) GSM cmpnents MS Mbile Statin max. transmit pwer is 2-20W MS nly wrks with a SIM (Subscriber Identificatin Mdule): smart card with memry identifies the subscriber in the netwrk can stre persnal data such as address bk can be prtected by PIN Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 19 Generatin 2 (2G) GSM cmpnents BTS Base (Transceiver) Statin is the ppsite f the MS is clse t the center f a cell Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 20 Generatin 2 (2G) GSM cmpnents BSC Base Statin Cntrller supervises several base statins frequency allcatin handver functinality Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 21

8 Generatin 2 (2G) GSM cmpnents (Gateway) Mbil Switching Center (G)MSC Interface t the fixed netwrk Cmplete switching system with all necessary ruting functinality t switch cnnectins within the system and the utside Cntains all relevant data fr each f the subscribers f the netwrk that perates this (G)MSC Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 22 Generatin 2 (2G) GSM cmpnents HLR Hme Lcatin Register is the hme f a subscriber be (actually the SIM) cntains all relevant data f all subscribers permanent data, e.g.: IMSI (Internatinal Mbile Subscriber Identificatin Number) is nt identical with phne number shared secrets (keys) infrmatin abut supplementary services f each subscriber tempral data, e.g. address f the current VLR destinatin fr call frwarding Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 23 Generatin 2 (2G) GSM cmpnents VLR Visitr Lcatin Register cntains all relevant ee data a f a subscriber be currently within a MSC tempral data are smewhat different frm HLR, e.g. TMSI (Tempral MSI), use fr cnfidentiality reasns, s that the IMSI desn t have t transmitted n the air interface several times Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 24

9 Generatin 2 (2G) GSM frequency 35 MHz bandwidth = 175 x 200 Khz channels (FDMA) 8 users per channel (TDMA) Mhz (uplink) Mhz (dwnlink) 891,2 Mhz 891,0 Mhz 890,8 Mhz 890,6 Mhz... channel 45 channel 44 channel Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 25 Generatin 2 (2G) GSM TDMA Mhz (uplink) Mhz (dwnlink) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 26 Generatin 2 (2G) GSM TDMA access t a frequency band is nly allwed during certain times (time slts) a mbile statin may have a slt in a TDMA frame MS A TDMA frame 4,615 ms Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 27

10 Generatin 2 (2G) GSM TDMA A mbile statin is allcated t the same TDMA time slt fr uplink and dwnlink, hwever, uplink and dwnlink are shifted by 3 slts, advantages: n sending and receiving at the same time less energy cnsumptin less cst Time Divisin Duplex dwnlink uplink Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 28 Generatin 2 (2G) GSM TDMA energy built up and dwn at the antenna (data burst) db (148 bits) 28 s s 28 s Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 29 Generatin 2 (2G) GSM TDMA structure f a Nrmal Burst in a time slt: T 3 User Data 57 Bits S 1 Training Sequence 26 Bits S 1 User Data 57 Bits T 3 GP 8, Bits = s T (Tail Bits) S (Signalling/User g Data) GP (Guard Perid) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 30

11 Generatin 2 (2G) GSM TDMA ther bursts: Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 31 Generatin 2 (2G) GSM Hierarchy f frames Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 32 Generatin 2 (2G) GSM Physical vs. Lgical channels Physical channels are frmed by all the available time slts in a BTS. If the BTS uses 6 frequency bands (carriers), the there are 48 physical channels. The lgical channels are a structure n tp f the physical nes. One physical channel may carry several lgical channels. Each lgical channel perfrms a specific task Lgical channels: Speech traffic channels (TCH) Full-rate TCH (TCH/F) Half-rate TCH (TCH/H) Bradcast channels (BCH) Frequency crrectin channel (FCCH) Synchrnizatin channel (SCH) Bradcast cntrl channel (BCCH) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 33

12 Generatin 2 (2G) GSM Physical vs. Lgical channels Lgical channels (cnt.): Cell bradcast channel (CBCH) Cmmn cntrl channels (CCCH) Paging channel (PCH) Access grant channel (AGCH) Randm access channel (RACH) Dedicated cntrl channel (DCCH) Slw assciated cntrl channel (SACCH) Stand-alne alne dedicated cntrl channel (SDCCH) Fast assciated cntrl channel (FACCH) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 34 Generatin 2 (2G) GSM Synchrnizatin Synchrnizatin f an MS with a netwrk (prcedure lasts 2-20 sec) BTS uses an FDMA carrier (ne cmplete 200kHz band) as a base channel On this channel the BTS transmits with maximum pwer, i.e. every single time slt in a frame is filled, mst f them with a dummy burst The MS lks fr a FCCH n this base channel If the FCCH has been fund the MS can synchrnise n frequency and time and lk fr the BCCH in the same frequency band. BCCH cntains infrmatin, e.g. fr describing the current cntrl channel structure and ther infrmatin abut the netwrk and hw t gain access Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 35 Generatin 2 (2G) GSM Lcatin update MS BTS BSC MSC VLR HLR Channel request Channel activatin cmmand Channel Activatin acknwledge Channel assignment Lcatin update request Authenticatin request Authenticatin respnse Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 36

13 Generatin 2 (2G) GSM Lcatin update (cnt.) MS BTS BSC MSC VLR HLR Cmparisn f Authenticatin parameters Assignment f the new area and the TMSI Acknwledgement f the new area and the TMSI Entry f fthe new area and TMSI int VLR and HLR Channel release Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 37 Generatin 2 (2G) GSM MOC Mbil-Originating-Call (MOC) MS BTS Channel request Channel assignment Call establishment request Authenticatin ti ti request Authenticatin respnse Ciphering cmmand Ciphering cmplete (nw ciphering) Setup message, indicating the desired number Call prceeding, the netwrk rutes the call t the desired number Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 38 Generatin 2 (2G) GSM MOC (cnt.) Mbil-Originating-Call (MOC) MS BTS Assignment f a traffic channel fr the user data Assignment cmplete, frm nw n all messages are exchanged n traffic channel Alerting, the called number is nt busy and the phne is ringing Cnnect, the called party accepted the call Cnnect acknwledge, nw the call is active and bth parties can talk t each ther Exchange f speech data Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 39

14 Generatin 2 (2G) GSM Handver If an MS in peratin mves frm ne cell t anther, a handver prcedure takes place The BTS tells the MS n the base channel a list f channels f neighburing cells The MS cnstantly measures the signal levels fr these channels f neighburing base statins The signal levels f the wn cell and thse f the neighburing cells are reprted back by the MS t the wn BTS If handver is necessary, i.e. the signal quality f a neighburing cell is significantly better than the wn ne, handver will be perfrmed Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 40 Generatin 2 (2G) GSM Handver (cnt.) receive level BTS ld receive level BTS new HO_MARGIN MS MS BTS ld BTS new Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 41 Generatin 2 (2G) GSM Handver (cnt.) Types f handver MS MS MS MS BTS BTS BTS BTS 1 Intra-Cell 2 Inter-Cell 3 Inter-BSC 4 Inter-MSC BSC BSC MSC BSC MSC Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 42

15 Generatin 2 (2G) GSM Handver (cnt.) Handver prcedure MS BTS ld BSC measurement measurement reprt result HO cmmand BSC ld HO decisin HO required HO cmmand HO cmmand HO access Link establishment clear cmmand clear cmplete clear cmmand clear cmplete MSC HO request BSC new BTS new resurce allcatin ch. activatin HO request ack ch. activatin ack HO cmplete HO cmplete Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 43 Generatin 2 (2G) GSM Services GSM ffers three service dmains Bearer Services Telematic Services Supplementary Services Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 44 Generatin 2 (2G) GSM Bearer Services Telecmmunicatin services t transfer data between access pints Specificatin f services up t the terminal interface (OSI layers 1-3) Different data rates fr vice and data (riginal standard) data service (circuit switched) synchrnus: 2.4, 4.8 r 9.6 kbit/s asynchrnus: bit/s data service (packet switched) synchrnus: 2.4, 4.8 r 9.6 kbit/s asynchrnus: bit/s In 2.5G much higher data rates are pssible, will be cvered later Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 45

16 Generatin 2 (2G) GSM Tele Services Telecmmunicatin services that enable vice cmmunicatin via mbile phnes All these basic services have t bey cellular functins, security measurements etc. Offered services mbile telephny primary gal f GSM was t enable mbile telephny ffering the traditinal bandwidth f 3.1 khz Emergency number cmmn number thrughut Eurpe (112); mandatry fr all service prviders; free f charge; cnnectin with the highest pririty (preemptin f ther cnnectins pssible) SMS (Shrt Message Service), alphanumerical shrt messages fr the display at the receiver mbile phne Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 46 Generatin 2 (2G) GSM Supplementary Services Services in additin t the basic services, cannt be ffered stand- alne Similar t ISDN services besides lwer bandwidth due t the radi link May differ between different service prviders, cuntries and prtcl versins Imprtant services: identificatin: frwarding f caller number suppressin f number frwarding autmatic call-back cnferencing with up t 7 participants lcking f the mbile terminal (incming r utging calls)... Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 47 Generatin 2 (2G) Other standards IS-95 (CDMAne): a Nrth American standard f 2G that already uses DS-CDMA n the Air interface. Culdn t gain much territry against GSM/UMTS and als it s fllw-up CDMA2000. Persnal Digital Cellular (PDC) Japanese Standard Based n TDMA 800 and 1500 MHz Physical characteristics similar t D-AMPS (the fllw up f the Nrth American AMPS standard) Nt successful utside Japan Japan was ne f the prime pusher f 3G (UMTS) Generatin 1 (1G) Mbile Cmmunicatin Wireless Telecmmunicatin 48