HISTORY & CONTEXT Jasleen Kaur Fall 2017

8/24/17

COMP 635: WIRELESS & MOBILE COMMUNICATIONS

HISTORY & CONTEXT

Jasleen Kaur

Fall 2017

SOME HISTORY Light, Electromagnetic Waves, TV, WLANs, …

Using Light for Communication

q Ancient Times: Ø Smoke signals (150 BC, Greece) Ø Light towers (206 BC, China)

q Not-so-ancient: Ø Heliographs, semaphores, navy

q 1794, Claude Chappe Ø Optical telegraph

Electromagnetic Waves

q Discovery of electromagnetic waves: Ø Faraday (1831): demonstrated electromagnetic induction Ø Maxwell (1860s-70s): theory of electromagnetic waves Ø Hertz (1886): demonstrated the wave character of electrical transmission

q Marconi (1896): Ø First demonstration of wireless telegraphy Ø Long-wave transmission, high transmission power needed (> 200 kW)

q 1907: Commercial transatlantic connections Ø Huge base stations (Thirty 100m high antennas)

q 1915: Wireless voice transmission (NY-SFO) Ø Still needed huge antennas, high transmission power

Small Antennas, Small Power

q 1920: Discovery of short waves (Marconi, again) Ø Get reflected at the ionosphere Ø Enabled sending short radio waves around the world, bouncing at the ionosphere § Technique still used today for amateur radio

q 1906: Invention of vacuum tube (DeForest, Leiben) Ø Helped reduce the size of senders and receivers Ø Still used for amplifying sender output in radio stations

q 1920s: Mobile Transmitters Ø First phone in a train (wires parallel to track as antennas) Ø 1927: First commercial car radio § 1922: 18-yr Frost (Chicago) integrated radio into a Ford

Rise of Broadcasting: TV & Radio

q 1928: Many TV broadcast trials Ø Baird: TV transmission across Atlantic, Color TV Ø WGY (Schnectady, NY): regular TV broadcasts, TV news

q 1932: CBS started first tele-teaching

q 1933: Frequency modulation (E.H. Armstrong) Ø Much better quality than amplitude modulation Ø Both FM and AM still used for today’s radio broadcasting § FM results in better quality

q 1930s: Ø Many radio stations broadcasting all over the world

Analog Mobile Phone Systems

q 1960s: Bell Labs, US completed initial cellular system design

q 1960s-70s: Several European mobile phone projects Ø German: A-Netz (1958), B-Netz (1972) § Carrier freq of 160 MHz, no handover § connection setup: – only from mobile station (A-Netz), fixed network too (B-Netz) § 1971: 80% coverage; 11,000 customers Ø Scandinavian countries: NMT (1979) – carrier freq 450 MHz

q 1982: Start of GSM specification Ø Several incompatible analog mobile phone standards

q 1983: US AMPS system started Ø Advanced Mobile Phone System – 850 MHz Ø Included handoffs

q 1984: CT1 (cordless home phone standard) Ø 1987: CT2 – carrier freq 864 MHz, channel rate 32 Kbps 7

Digital Wireless Systems

q 1991: DECT (Digital European Cordless Telephone) Ø 1880-1900 MHz; 100 – 500 m range; 120 duplex channels Ø 1.2 Mbps data transmission; encryption, authentication Ø Up to several 10000 users/km2 ; used in 110+ countries Ø Renamed: Digital Enhanced Cordless Telecommunications

q 1992: Start of GSM (standardized) Ø 900 MHz, 124 duplex channels Ø Full international roaming, automatic location services, authentication, encryption, interoperation with ISDN, relatively high quality audio Ø Includes SMS, fax, data services (9.6 Kbps) Ø Offers compatibility despite provider accounting diversity § Currently 400 providers, 190 countries, 70% of world market Ø Renamed: Global System for Mobile Communication 8

Mobile Communication w/ Satellites

q 1998: Iridium system Ø 66 satellites in low earth orbit; uses the 1.6 GHz band Ø First small and truly portable mobile satellite phones § Including data service

q 1998: UMTS (European) Ø Universal Mobile Telecommunications System Ø Combines GSM with bandwidth-efficient CDMA solutions

q IMT-2000: International Mobile Telecommunications Ø ITU worldwide framework for future mobile communication Ø Service framework, network architecture, radio interface requirements, spectrum considerations, … Ø Includes strategies for developing countries

WLAN: Wireless Local Area Networks

q 1996: HIPERLAN (European) Ø High-performance Radio LAN family of standards Ø Type 1 (5.2 GHz, 23.5 Mbps) – Type 4 (17 GHz, 155 Mbps)

q 1997: IEEE 802.11 standard Ø Uses the License-free Industrial, Science, Medical band § 2.4 GHz and infra-red Ø Initially offering 2 Mbps

q 802.11 emerged as winner for LANs Ø Standards vs. market forces Ø In contrast to GSM vs. US technologies

q 1999: more powerful WLAN standards Ø IEEE 802.11b: 2.4 GHz, 11 Mbps Ø Bluetooth: 2.4 GHz, < 1 Mbps, short-range, piconets

Third Generation (3G)

q 2000: GSM higher data rates (up to 57.6 Kbps)

q Late 90s: UMTS spectrum auctions Ø Hype: portraying 3G as high-performance mobile Internet § UMTS announced as capable of handling interactive video streaming for all users at 2 Mbps Ø Thus, auctions for licensing 3G spectrum started Ø More than 100 Billion pounds paid in Europe alone § Companies that had never run a network before paid billions § Most companies now bankrupt

q 2001: Start of 3G systems Ø FOMA (Japan), UMTS (Europe) cdma2000 (Korea)

2000s

q Early 2000s: New WLAN developments Ø IEEE 802.11a: 5 GHz, up to 54 Mbps Ø IEEE 802.11g: 2.4 GHz, up to 54 Mbps Ø New Bluetooth applications: § Headsets, remote controls, wireless keyboards, hot syncing

q Deployment of 3G infrastructure (licensing pre-condition)

q Digital terrestrial TV: high quality, mobile, small antenna

q Next generation mobile and wireless systems: Ø Likely to be widely Internet based (IP protocols/apps) Ø Users will have choice of many different networks

q 2009: Netbooks, iphones, VoIPoWLAN, …

q Latest: 802.11ac, 802.11ad, GigaIR, WUSB-UWB, … 12

CURRENT STATE OF AFFAIRS Market & Spectrum

Explosion of User Base

100.0 Mobile cellular telephone subscriptions

90.0 Fixed -telephone subscriptions Active Mobile-broadband subscriptions 80.0 Fixed broadband subscriptions 70.0 Internet Users 60.0

50.0

40.0

30.0

20.0

10.0

- 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015*

~ 7 billion current mobile phone service subscriptions è more than 96% of world population ! 14

Cellular Subscribers Per Region

Regions Regions – September 2008- 2015

8% 19%0% 5%15% Africa 161%% Africa Americas 13% 11% Arab States Asia Pacific Asia & Pacific Europe: Eastern CIS Europe: Western 5%11% Europe Middle East The USA/Canada Americas 43% 53% www.gsmworld.com

Cellular Subscribers Per Technology

90 80 70 60 50

Percent 40 30 20 10 0

September 2008 www.gsmworld.com

Spectrum Allocation

q Limited frequency spectrum Ø Must be shared among various applications Ø Typically government regulated

q US spectrum allocation chart: http://www.ntia.doc.gov/osmhome/allochrt.html

q More in next lecture-set …

EXAMPLES OF WIRELESS COMMUNICATION SYSTEMS Paging, Cordless, Cellular

Some Terminology

q Portable (hand-held, walk speed) vs mobile (vehicle speed)

q Base stations: mobiles communicate to fixed base stations Ø Connected to power source, and a backbone network

q Classification: Ø Simplex systems: e.g., paging systems § Messages are received, but not acknowledged. Ø Half-duplex systems: e.g., walkie-talkies § Allow two-way communication, but use same radio channel for both transmission and reception. § “push-to-talk”, “release-to-listen” Ø Full-duplex systems: e.g., US AMPS standard § Allow simultaneous radio transmission and reception § Provide two separate channels (frequency division duplex), or adjacent time slot on a single channel (time division duplex)

Paging Systems

q Service: Ø Send brief messages to a subscriber Ø Simplex, reliable communication

q Architecture: Ø Transmit the page throughout the service area using base stations, which simultaneously broadcast the page on a radio carrier Ø Reliability achieved using large transmission power (~kw) and low data rates (~Kbps) 20

Cordless Telephony

q Full duplex in-home communication system Ø Radio connects portable handset to dedicated base station, which is connected to a dedicated phone line • nd q 2 -generation systems cover up to 100s of meters Ø But no coverage outside range

Cellular Systems

q Provides wireless connection to the PSTN for any user location within the system range

q Accommodate large number of users (using cells) over a large geographic area (using handoffs), within a limited frequency spectrum

q Base station Ø Several antennas Ø Full duplex Ø Connects to MSC

q MSC (Mobile Switching Center): Ø Handles channel allocation in base stations Ø Involved in call initiation, termination, and handoff 22

ARCHITECTURAL CONTEXT Layered Reference Model

Internet Structure

q Internet is a “network of networks” Ø A packet passes through many networks

local local ISP Tier 3 local local ISP ISP ISP ISP Tier-2 ISP Tier-2 ISP Tier 1 ISP NAP

Tier 1 ISP Tier 1 ISP Tier-2 ISP local Tier-2 ISP Tier-2 ISP ISP local local local ISP ISP ISP 25

Organizing the Structure

q Networks are diverse and complex Ø Many pieces and many designers § Hosts § Routers § Links of various media § Applications § Protocols § Hardware, software

Use layering for accommodating diversity and managing complexity

Why Layering?

q Explicit structure allows identification, relationship of complex system’s pieces

q Modularization eases maintenance, updating of system Ø Change of implementation of a layer transparent to rest of system

q Standard, well-defined interfaces a must Ø Single, simple IP glues the Internet together

Internet Protocol Stack

q Application layer Ø Supporting network applications application § ftp, SMTP, HTTP transport q Transport layer Different services Ø Host-host data transfer specified at each layer § TCP, UDP interface network q Network layer link Ø Routing of packets from source to destination § IP, routing protocols physical q Link layer Ø Data transfer between directly connected network elements § Ethernet, 802.11, SONET, …

q Physical layer Ø The insertion of individual bits “on the wire” 28

Impact of Wireless on Protocol Layers

Application layer service location new/adaptive applications multimedia Transport layer congestion/flow control quality of service Network layer addressing, routing device location hand-over Data link layer authentication media access/control multiplexing encryption Physical layer modulation interference attenuation frequency