Mobile Radio Communications

Transcription

1 Session 1: Introduction Session 1, page 1

2 COMMUNICATIONS information source channel information sink Session 1, page 2

3 HISTORY: stone age Initial communications were wireless: human voice (air pressure) visual messaging fires along chinese wall (3000 B.C.) Indian smoke signalling Semaphores Session 1, page 3

4 HISTORY: electrical era Communications through a wire: 1729 Stephen Gray: electrostatic telegrahp A B C Session 1, page 4

5 HISTORY: electrical era Communications through a wire: 1850 Telegraph lines across US (Morse code) Submarine cables in the English Channel Alexander Graham Bell: telephony DIGITAL ANALOG Session 1, page 5

6 HISTORY: radio era Communications through free space: Heinrich Rudolf Hertz: EM waves Guglielmo Marconi: RADIO Detroit Police Radio Armstrong: Frequency Modulation Cellular concept (Bell labs) / trunked radio Session 1, page 6

7 Electrical transmission Guided wave transmission: guided by material copper/fiber Unguided wave transmission: free-space propagation radio, EM waves Session 1, page 7

8 Modern mobile communications Analog cellular radio: 1 st generation - reachability - voice, voice, voice Digital cellular radio: 2 nd generation - improved capacity - improved performance - lower cost - security - voice, voice, data Wideband cellular radio: 3 rd generation - increased data rate - packet services - multimedia services Session 1, page 8

9 Why 1 st generation analog? History Messaging: light on/off keying semaphore multilevel telegraph, marine radio Morse code Telephony voice } digital analog ANALOG TELEPHONE LINE ANALOG MOBILE RADIO Session 1, page 9

10 Why 2 st generation digital? Performance improved spectral efficiency increased capacity improved voice quality time division cheaper radio implementation encryption Session 1, page 10

11 Why 3 rd generation at all? Services new IMT-2000 spectrum available increased data rates multimedia services service flexibility / differentiation CIRCUIT ORIENTED PACKET ORIENTED Session 1, page 11

12 Circuit switching Reserved circuits Constant bandwidth Telephony paradigm SWITCH SWITCH Session 1, page 12

13 Packet switching Packet transmission Variable bandwidth Data paradigm ROUTER ROUTER Session 1, page 13

14 System classification (1) Mobile systems MSC PSTN PLMN BSC Session 1, page 14

15 System classification (2) Wireless extensions PSTN Session 1, page 15

16 System classification (3) Ad-hoc connectivity Session 1, page 16

17 Radio systems in use Mobile systems (public cellular, cell phone systems) AMPS: Advanced Mobile Phone System NMT: Nordic Mobile Telephone system (E)TACS: (Extended) Total Access Cellular System GSM: Groupe Spéciale Mobile/Global System for Mobile communication, PCS1900, DCS1800 IS-136: Interim Standard 136 (formally IS-54), D-AMPS, USDC Pacific Digital Cellular PDC: IS-95: Intermin Standard 95 Session 1, page 17

18 Radio systems in use Future Mobile systems UMTS: Universal Mobile Telephone System CDMA2000 IMT-2000: International Mobile Telecommunications (formerly FPLMTS: Future Public Land Mobile Telephone Systems) 3G, 3GPP: Third Generation Partnership Project Session 1, page 18

19 Radio systems in use Wireless extensions DECT: Digitally Enhanced Cordless Telephony system PHS: Personal Handy Phone System WLAN : Wireless Local Area Network HIPERLAN: High Performance Local Area Network Session 1, page 19

20 Radio systems in use Ad-hoc connectivity Walky-talky Bluetooth TM Session 1, page 20

21 Public versus private Private emergency/rescue (land-mobile radio) company/campus (WLAN) Public telephony internet IMPORTANCE STANDARDS Session 1, page 21

22 Paging systems One-way messaging Replaced by two-way cellular solutions US use due to billing Satellite use due to in-building penetration Paging functionality in cellular systems ERMES, (RE-)FLEX Session 1, page 22

23 Paging in cellular systems Location areas Location registers VLR MSCI HLR MSC LA1 LA2 LA3 Session 1, page 23

24 Mobile satellite systems GEO: geostationary earth orbit INMARSAT ACeS (Asia Cellular Satellite MEO: medium earth orbit ICO LEO: low earth orbit GLOBALSTAR IRIDIUM Satellite mode in IMT-2000 Session 1, page 24

25 System definitions operator subscriber, user base station mobile station mobile, terminal, portable, handy, cell phone forward reverse channel (downlink/uplink) control & traffic channels paging roaming Session 1, page 25

26 Forward and reverse transmissions unit A unit B SIMPLEX FULL DUPLEX HALF DUPLEX t=t0 t=t1 Session 1, page 26

27 How to design a radio system? System architecture Frequency band Multiple access method Medium access control Call setup Standby mode Radio protocol Security Session 1, page 27

28 How a mobile call is made Locking Registration Idle/standby mode Mobile-originated call: connection request Mobile-terminated call: page Session 1, page 28

29 Registration Mobile scans for forward CCH Registration VLR MSCI HLR MSCI AUCI Session 1, page 29

30 Registration Subscriber identity MIN: Mobile Identification Number IMSI: Internation Mobile Subscriber Identity SIM: Subscriber Identity Mobile Equipment identity ESN: Electronic Serial Number IMEI: Internation Mobile Equipment Identity Authentication Roaming Session 1, page 30

31 Connection Paging / channel request Authentication (billing) Traffic channel assignment Hand-off Attach/detach Session 1, page 31

32 Radio spectrum usage MHz MHz 3-30 MHz MHz MHz 1-10 GHz GHz LF MW HF VHF UHF microwave millimeter wave long-distance communications AM radio broadcasting CB radio TV and FM radio broadcasting mobile radio mobile radio, satellite satellite Session 1, page 32

33 Why radio in 300MHz - 30GHz? antenna dimensions: λ/4 = c/4f path loss: PL = -10log(λ 2 /(4πd) 2 ) shadowing, directional 0.3 GHz < f < 30 GHz 1 m < λ < 1 cm Session 1, page 33

34 Spectrum allocation cellular analog cellular digital unlicensed Session 1, page 34

35 Licensed and unlicensed licensed unlicensed dedicated undedicated public cellular telephony high-power applications cordless telephonly local area Session 1, page 35

36 Regulatory bodies CEPT: Conférence Européne des Administration des postes et des télécommunications ETSI: European Technical Standards Institute FCC: Federal Communications Commission MPT: Ministry of Posts and Telecommunications of Japan ITU-R: International Telecommunications Union - Radiocommunication section WARC: World Administration Radio Conference Session 1, page 36

37 Standardization bodies ETSI: European Technical Standards Institute TIA: Telecommunications Industry Association ARIB: Association of Radio Industries and Businesses ITU: International Telecommunications Union IEEE: Institute of Electrical and Electronics Engineers Session 1, page 37

38 FDD AND TDD FDD forward reverse f TDD forward/reverse f Session 1, page 38

39 A layered structure OSI protocol stack application session application session transport transport network network data link data link physical physical Session 1, page 39

40 From source to sink information source information sink source coding channel coding source decoding channel decoding modulation transmission radio propagation demodulation reception Session 1, page 40

41 Source coding/decoding Remove redundancy Minimize amount of information to be transmitted Voice: Data: Video: vocoders (model + excitation), LPC spaces, Huffman coding transform techniques (DCT) Not covered in this course. Chapter 7 in book for those interested. Session 1, page 41

42 Channel coding/decoding Add controlled redundancy Correlation between correct and incorrect bits HELPS ONLY IF CHANNEL CONDITIONS VARY: good bits help bad bits Session 5: Equalization, channel coding, and interleaving Session 1, page 42

43 Modulation/demodulation Mapping of bits to symbols Mapping of symbols to physical parameters AMPLITUDE / PHASE Q AM PM I Session 4: Modulation & transmission Session 1, page 43

44 Transmission/reception Up and downconversion from baseband to RF Amplification, filtering I Q Σ PA LNA ~ cos sin sin Session 4: Modulation & transmission Session 1, page 44

45 Propagation channel Radio wave propagation Noise, range Blocking, shadowing, diffraction Multi-path effects, reflections Session 3: Radio propagation Session 1, page 45

46 Multi-path effects λ T s τ τ T s fading inter-symbol interference Session 1, page 46

47 Fading Session 1, page 47

48 Interference Co-channels and adjacent channels Capacity Medium access Session 2: The cellular concept Session 6: Multiple access Session 1, page 48

49 Radio systems Session 7: Wireless LAN systems Session 8: Mobile systems Session 9: Ad-hoc systems Session 1, page 49

50 FOR NEXT WEEK Read: Chapter 1: Chapter 2: (not 2.7.3) Chapter 8: 8.7 Solve problems: Chapter 1: 1.5, 1.6, 1.8, 1.10 Session 1, page 50

51 Case study UMTS frequency auctioning: UK: GBP 22.5 billion Germany: DM 99 billion Holland: DFL 5.9 billion How many years before break-even point? Session 1, page 51

52 Penetration Population: UK: Germany: Holland: 59 million 82 million 16 million Subscriber growth: year 1: 0.5% of population year 2: 2% year 3: 10% year 4 and beyond: 30% Session 1, page 52

53 User traffic & expenses Usage pattern: voice: data: 10 minutes/day 10Mbytes/day Billing: subscription: DFL 25 / month voice: DFL 0.25/minute data: DFL 0.10/Mbyte Total: DFL = DFL /user year Session 1, page 53

54 Operator expenses Network roll-out: DFL 150 per (expected) user Operation&maintenance: DFL 200 per user License Session 1, page 54