Mobile Communications I Chapter 1: Introduction and History. Applications History Development of wireless systems

Transcription

1 Mobile Communications I Chapter 1: Introduction and History Applications History Development of wireless systems

2 Wireless networks in comparison to fixed networks Higher loss-rates due to interference and other mechanisms in wireless transmission emissions of, e.g., engines, lightning (only in lower frequency range up to 200 MHz) mainly interference with other users in the higher frequency range As a rule of thumb: BER (wired) ; BER (wireless) Restrictive regulations for use of frequencies frequencies have to be coordinated, useful frequencies are almost all (statically) occupied New approaches for cognitive radio is in research and development (overlay/ underlay approaches) Transmission rates typically lower than in wired networks local >>100 Mbit/s, cellular currently up to 30 (HSPA+) In the new generation of cellular networks the speed difference between Local and regional will not play any more any role. E.G. LTE will support up to 100 Mb/s Wired fiber based communication > 10Gb/s Higher delays, higher delay-jitter connection setup time with GSM in the second range, several hundred milliseconds for other wireless systems Jitter and delay may impact the QoS (quality of service) but with LTE low latency services that will be as good as in wired networks Lower security, simpler active attacking radio interface accessible for everyone, base station can be simulated, Security is an important issue of research in wireless systems Always shared medium The capacity of a network is divided between the participants. This is a growing concern for the further development of wireless systems. Chapter 1 Page 54

3 Early history of wireless communication Many people in history used light for communication heliographs, flags ( semaphore ), BC smoke signals for communication; (Polybius, Greece) 1794, optical telegraph, Claude Chappe Here electromagnetic waves are of special importance: 1831 Faraday demonstrates electromagnetic induction J. Maxwell ( ): theory of electromagnetic fields, wave equations (1864) H. Hertz ( ): demonstrates with an experiment the wave character of electrical transmission through space Chapter 1 Page 55

4 History of wireless communication I 1896 Guglielmo Marconi first demonstration of wireless telegraphy (digital!, UWB puls-transmission) long wave transmission, high transmission power necessary (> 200 kw) 1907 Commercial transatlantic connections huge base stations (30*100 m high antennas) 1915 Wireless voice transmission New York - San Francisco 1920 Discovery of short waves by Marconi reflection at the ionosphere (radio works arround the spheric-shape of the earth) smaller transmitter and receiver, possible due to the invention of the vacuum tube which allows to build amplifiers for signals (LNA Low Noise amplifier; PA power amplifier) (1906, Lee DeForest and Robert von Lieben) 1926 Train-phone on the line Hamburg Berlin wires parallel to the railroad track Chapter 1 Page 56

5 History of wireless communication II 1928 many TV broadcast trials (across Atlantic, color TV, TV news) 1933 Frequency modulation (E. H. Armstrong) 1958 A-Netz in Germany analog, 160 MHz, connection setup only from the mobile station, no handover, 80 % coverage, customers 1972 B-Netz in Germany analog, 160 MHz, connection setup from the fixed network too (but location of the mobile station has to be known) available also in A, NL and LUX, customer in D 1979 NMT (Nordic Mobile Telecommunication) at 450 MHz (in Scandinavian countries) 1982 Start of GSM-specification goal: pan-european digital mobile phone system with roaming 1983 Start of the American AMPS (Advanced Mobile Phone System, analog) 1984 CT-1 (Cordless Telephony) standard (Europe) for home use Chapter 1 Page 57

6 History of wireless communication III 1986 C-Netz in Germany analog voice transmission, 450 MHz, hand-over possible, digital signaling, automatic location of mobile device was in use until 2000, services: FAX, modem, X.25, , 98 % coverage 1988 first discussion of UMTS networks as a solution of a worldwide wireless communication system (later known as IMT-2000 ) 1991 Specification of DECT Digital European Cordless Telephone (today: Digital Enhanced Cordless Telecommunications) MHz, ~ m range, 120 duplex channels, 1.2 Mbit/s data transmission, voice encryption, authentication, up to several user/km 2, used in more than 50 countries 1992 Start of GSM commercial operation in D as D1 and D2, fully digital, 900 MHz, 124 channels automatic location, hand-over, cellular roaming in Europe - now worldwide in more than 200 countries services: data with 9.6 kbit/s, FAX, voice,... Chapter 1 Page 58

7 History of wireless communication IV 1994 E-Netz in Germany GSM with 1800 MHz, smaller cells As Eplus in D ( % coverage of the population) 1996 HiperLAN (High Performance Radio Local Area Network) as part of BRAN (Broadband Radio Access Network) ETSI, standardization of type 1: GHz, 23.5 Mbit/s recommendations for type 2 and 3 (both 5 GHz) and 4 (17 GHz) as wireless ATM-networks (up to 155 Mbit/s) 1997 Wireless LAN - IEEE IEEE standard, GHz and infrared, 2 Mbit/s already many (proprietary) products available at the beginning 1998 Specification of GSM successors for UMTS (Universal Mobile Telecommunication System) as European proposals for IMT Iridium 66 satellites (+6 spare), 1.6 GHz to the mobile phone Chapter 1 Page 59

8 History of wireless communication V 1999 Standardization of additional wireless LANs IEEE standard b, GHz, 11 Mbit/s Bluetooth for piconets, 2.4 Ghz, < 1 Mbit/s Decision about IMT-2000 Several members of a family : UMTS, cdma2000, DECT, Start of WAP (Wireless Application Protocol) and i-mode First step towards a unified Internet/mobile communication system Access to many services via the mobile phone 2000 GSM with higher data rates HSCSD offers up to 57.6 kbit/s First GPRS trials with up to 50 kbit/s (packet oriented!) UMTS auctions/beauty contests Hype followed by disillusionment (100 B DM paid in Germany for 6 licenses!) 2001 Start of 3G systems (Release-99) CDMA 2000 in Korea, UMTS tests in Europe, FOMA (almost UMTS) in Japan GPP took over further international standardization of cellular radio networks 2010 Roll out of first LTE systems in Germany Chapter 1 Page 60

9 Global ICT development Chapter 1 Page 61

10 Wireless systems: Overview of the development cellular phones 1981: NMT : NMT : GSM 1994: DCS : GPRS 2008 (dev. end): UMB 1983: AMPS 1991: CDMA 1991: D-AMPS 1993: PDC 2001:IMT : IMT-SC EDGE (UWC-136) 2002: IMT-MC CDMA : IMT-TC UMTS 2001: IMT-DS UMTS 2010: LTE Year?: LTE Advanced satellites 1982: Inmarsat-A 1988: Inmarsat-C 1992: Inmarsat-B Inmarsat-M 1998: Iridium 2005: M Satelliten time cordless phones 2001: IMT-FT DECT 1980: CT0 1984: CT1 1987: CT : CT : DECT wireless LAN 2007: IP-OFDMA WiMAX digital analogue 199x: proprietary 1997: IEEE : b; Bluetooth 2004: WiMAX 2000: a 2005: e mobile WiMAX 2009: n 2011: ac/ad Chapter 1 Page 62

11 FDMA CDMA TDMA OFDMA Development of mobile telecommunication systems CT0/1 AMPS NMT CT2 IS-136 TDMA D-AMPS GSM PDC GPRS EDGE IMT-FT DECT IMT-SC IS-136HS UWC-136 IMT-DS UTRA FDD / W-CDMA IMT-TC UTRA TDD / TD-CDMA HSPA IMT-TC TD-SCDMA UMB IS-95 cdmaone cdma2000 1X IMT-MC cdma2000 1X EV-DO Rev.0 (1X EV-DV (3X)) 2005 aufgegeben cdma2000 1X EV-DO Rev.A & Rev.B LTE LTE Advanced 1G 2G 2.5G 3G 3G Trans. 4G Chapter 1 Page 63

12 Wireless Communication Areas of research in mobile communication capacity and bandwidth efficiency due to shortage in available spectrum transmission quality (bandwidth, error rate, delay) modulation, coding, interference media access, regulations security and reliability Cognitive Radio based on SDR (software defined radio) systems Mobility location dependent services location transparency quality of service support (delay, jitter, security)... Portability power consumption limited computing power, sizes of display,... usability Chapter 1 Page 64

13 Development of Mobile Access Speed Source: VTC-2007, Fettweis Chapter 1 Page 65

14 Simple reference model used here Application Application Transport Transport Network Network Network Network Data Link Data Link Data Link Data Link Physical Physical Physical Physical Radio Medium Chapter 1 Page 66