COMMUNICATION SECURITY LECTURE 3 INTRODUCTION TO CELLULAR MOBILE

COMMUNICATION SECURITY LECTURE 3: INTRODUCTION TO CELLULAR MOBILE NETWORKS Dr. Shahriar Bijani Shahed University Spring 2016

MAIN REFERENCES A. S. Tanenbaum and D. J. Wetherall, Computer Networks (5 th Edition), Pearson Education, the book slides, 2011. Patrick Traynor, CS 8803 - Cellular and Mobile Network Security, Georgia Tech Information Security Center, 2012. General Packet Radio Service (GPRS) For Engineers, Aircom International. 2

OUTLINE Circuit Switching vs. Packet Switching Multiplexing Mobile Phone Standards Figures 3

CIRCUIT SWITCHING CIRCUIT SWITCH CIRCUIT SWITCH

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 5 4 3 2 1 PACKET SWITCH 4 3 PACKET SWITCH 2 5 PACKET SWITCH 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 5 4 3 2 1 PACKET SWITCH 4 2 1 3 2 1 PACKET SWITCH 3 2 5 PACKET SWITCH 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 1 5 4 3 2 1 PACKET SWITCH 4 2 3 3 PACKET SWITCH 3 PACKET SWITCH 2 5 2 1 PACKET SWITCH 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 1 PACKET SWITCH 4 3 PACKET SWITCH 1 3 PACKET SWITCH 2 3 4 5 2 PACKET SWITCH 3 2 1 PACKET SWITCH 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 5 4 3 2 1 PACKET SWITCH 4 PACKET SWITCH 3 3 1 2 PACKET SWITCH 2 5 2 PACKET SWITCH 3 1 PACKET SWITCH 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 5 4 3 2 1 1 PACKET SWITCH 4 3 PACKET SWITCH 2 5 PACKET SWITCH 2 3 1

PACKET SWITCHING PACKET ASSEMBLER/ DISASSEMBLER 1 3 2 2 4 PACKET SWITCH 1 3 PACKET SWITCH 3 1 2 2 2 1 3 2 3 3 3 1 1 PACKET SWITCH 2 3 4 5 2 1 PACKET SWITCH 3 1 PACKET SWITCH 2 3 1

ADVANTAGES OF PACKET SWITCHING More efficient use of existing carriers More suited to bursty-type traffic such as Internet access. Compatibility with existing packet-switched networks (PSNs) such as the Internet

ADVANTAGES OF CIRCUIT SWITCHING More suited to time-sensitive applications No contention for network resources Less data overheads for routing requirements Compatibility with existing circuit-switched networks (eg PSTN/ISDN)

PACKET ROUTING STRATEGIES Connection-Orientated (CONS): � Packet route established prior to data transfer � Supports flow control � Supports Qo. S functions Connectionless (CNLS) � No predefined route - packets routed individually � No guarantee of delivery � Difficult to implement Qo. S

PACKET DATA DELIVERY Acknowledged Mode: Guarantees error-free delivery � Supports flow control � Requires additional overheads � Lower data throughput � Unacknowledged Mode Packets are delivered to the network and forgotten � No indication of delivery or error correction � Generally relies on higher layer protocols for error detection and correction � More efficient in reliable networks �

PACKET SWITCHING TECHNOLOGIES X. 25 Frame Relay ATM

THE VIRTUAL CIRCUIT (VC) CONCEPT Virtual Circuit 1 3 2 2 1 1 2 3 1 PACKET SWITCH 3 3 2 2 3 PACKET SWITCH 1 3 PACKET SWITCH 2 1 3 2 1 2 PACKET SWITCH Virtual Circuit 3 1 PACKET SWITCH 2 3 1

VIRTUAL CIRCUIT CONNECTIONS Permanent Virtual Circuit (PVC): � Established by NMC � Dedicated resource for specific user � Connectionless Switched Virtual Circuit (SVC): � Setup on request � Temporary allocation of resources � Cleared on completion of session

OUTLINE Circuit Switching vs. Packet Switching Multiplexing Mobile Phone Standards Figures 19

MODULATION & MULTIPLEXING Modulation: To send digital information, we must change analog signals to represent bits. � includes: � Example: PCM (Pulse Code Modulation) sampling quantizing Encoding the simplest form of speech coding 2 standards: A-law in Europe (24 -channels), and µ-law in the USA (30/32 channels). Multiplexing: sharing one channel by multiple signals Using a single channel (wire) to carry several signals is better than to allocate a channel (install a wire!) for every signal. 20

MULTIPLEXING Different multiplexing methods: � Frequency Division Multiplexing (FDM) � Time Division Multiplexing (TDM) � Code Division Multiplexing (CDM) � Beam Division Multiplexing (BDM) 21

FREQUENCY DIVISION MULTIPLEXING (FDM) AKA: Frequency Division Multiple Access (FDMA) FDM: � divides the spectrum into frequency bands � each user having exclusive ownership of some band to send their signal. E. g. : AM radio. The allocated spectrum is about 1 MHz (~ 500 to ~1500 k. Hz) � Different frequencies are allocated to different logical channels (stations) � 22

FREQUENCY DIVISION MULTIPLEXING (FDM) (a) The original bandwidths. (b) The bandwidths raised in frequency. (c) The multiplexed channel. 23

TIME DIVISION MULTIPLEXING (TDM) AKA: Time Division Multiple Access (TDMA) TDM is used widely as part of the telephone and cellular networks. TDM is different from STDM (Statistical Time Division Multiplexing): � Channel is allocated according to the statistics of each stream’s demand � STDM is packet switching. 25

CODE DIVISION MULTIPLE ACCESS (CDM) AKA: Code Division Multiple Access (CDMA) Narrowband signal is spread over a wider frequency band. Advantages: � More tolerant of interference, � Allowing multiple signals from different users to share the same frequency band. 26

BEAM DIVISION MULTIPLE ACCESS (BDM) AKA: Beam Division Multiple Access (BDMA) New access technique for 5 th generation of mobile wireless communication. The base station allocates separate antenna beams to each of the mobile devices. Based on position and moving speed, base station will calculate both width and direction of the beam for all the mobile stations. BDMA helps in achieving higher system capacity. 27

MULTIPLE-ACCESS RADIO TECHNIQUES Courtesy of Petri Possi, UMTS World

CDMA Courtesy of Suresh Goyal & Rich Howard

ANALOG VS. DIGITAL TELEPHONE SYSTEMS Analog/ Digital telephone systems: Analog is the translation of voice into electrical impulses (pure waveform). � Cheap � Low bandwidth (limited data communication). � Noise Digital is an approximation of the waveform, represented in 0 s and 1 s � Expensive � High bandwidth � Better voice (less noise) 35

WIRELESS INTERNET VS. CELLULAR NET The Internet - Wireless Networks Classic Cellular Telecommunications Networks � Designed for voice, not for Internet access 36

OUTLINE Circuit Switching vs. Packet Switching Multiplexing Mobile Phone Standards Figures 37

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MOBILE PHONE STANDARDS 41

A COMPARISON OF ALL MOBILE GENERATIONS Technology Features Start/ Deployment Data Bandwidth 1 G 2 G 3 G 4 G 5 G 1970 / 1984 1980 / 1999 1990 / 2002 2000/ 2010 2020 2 kbps 64 kbps 2 Mbps 200 Mbs/ 1 Gbps + Wi. Max , LTE, Wi-Fi Unified IP & seamless combination of broadband , LAN, WAN, PAN, WLAN & www TACS, AMPS (Analog Cellular Technology) TDMA, CDMA, GSM, GPRS, EDGE (Digital) Mobile Telephony (Voice) Digital voice, SMS, Higher capacity packetized data Integrated high quality audio, video and data Multiplexing FDMA TDMA, CDMA Switching Circuit, Packet (Circuit, ) Packet All Packet Core Network PSTN Packet Network Internet Horizontal and Vertical Horizontal and Vertical Standard Service Handoff WCDMA, CDMA-2000, HSPA Dynamic Information access, Wearable devices with AI capabilities CDMA, BDMA

GSM / 3 GPP RELEASES GSM Phases GSM Release Start Date GSM Phase 1 1992 GSM Phase 2 1994 GSM Phase 2+ 1997 GSM Phase 2+ Release 97 1998 GSM Phase 2+ Release 99 (3 GPP UMTS Release 99) 1999 2000 3 GPP Releases Release 4 (all IP) Start Date 2001 … Release 7 Release 8 (LTE) Release 8 (LTE Advanced) Release 13 Release 14 2007 -8 2008 -9 2016 2017 43

MOBILE NETWORKS’ FIGURES Compound Annual Growth Rate 44

Compound Annual Growth Rate Mobile Usage 45 Source: Ericsson, Nov. 2015

Total number of mobile subscribers in Q 3 2015: ~7. 3 billion 87 million new subscribers 46 Source: Ericsson, Nov. 2015

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average 1. 7% of Android smartphone users upgraded to a new Android smartphone 49

Wi-Fi traffic is not included. Average data consumption increases between 20% and 45% per subscription after smartphone model upgrades 50

IRAN’S FIGURES Source: GSMA Intelligence 2016 Q 4 2015 Connections: 113. 9 M 4. 90% (annual growth) � Prepaid 71% -1. 07% � mobile broadband (includes 3 g & 4 G) 14% � Population 79. 6 M 1. 21% � SIM penetration 143% 3. 66% 2, 125% 51