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Introduction to IP-Based Next Generation Wireless Networks

Introduction to IP-Based Next Generation Wireless Networks. 1.1 Evolution of Wireless Networks 1.2 Evolution of Public Mobile Services 1.3 Motivations for IP-Based Wireless Networks 1.4 3GPP, 3GPP2, and IETF. 1.1 Evolution of Wireless Networks.

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Introduction to IP-Based Next Generation Wireless Networks

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  1. Introduction to IP-Based Next Generation Wireless Networks

  2. 1.1 Evolution of Wireless Networks 1.2 Evolution of Public Mobile Services 1.3 Motivations for IP-Based Wireless Networks 1.4 3GPP, 3GPP2, and IETF

  3. 1.1 Evolution of Wireless Networks • Based on radio coverage ranges, wireless networks can be categorized into • Wireless Personal Area Networks (PANs) • Wireless Local Area Networks (WLANs) • low-tier wireless systems • public wide-area (high-tier) cellular radio systems • mobile satellite systems

  4. Coverage Area Sizes v.s. Bit Rates

  5. PANs • use short-rangelow-power radios to allow a person or device to communicate with other people or devices nearby

  6. Example • Bluetooth • supports three power classes, which provide radio coverage ranges up to approximately 10m, 50m, and 100m, respectively • supports bit rates up to about 720Kbps

  7. HomeRF • a wireless networking specification (Shared Wireless Access Protocol-SWAP) for home devices to share data • uses frequency hopping spread spectrum (FHSS) in the 2.4 GHz frequency band and could achieve a maximum of 10 Mbit/s throughput

  8. its nodes can travel within a 50 meter range of an access point while remaining connected to the PAN • allows both traditional telephone signals and data signals to be exchanged over the same wireless network • in HomeRF, cordless telephones and laptops, for example, could share the same bandwidth in the same home or office

  9. IEEE 802.15 (WPAN) • defines a short-range radio system to support data rates over 20Mbps

  10. applications • example • allow a person to communicate wirelessly with devices inside a vehicle or a room • people with PDAs or laptop (notebook) computers may walk into a meeting room and form an ad-hoc network among themselves dynamically

  11. a service discovery protocol may be used over a PAN to help individuals to locate devices or services (e.g., a printer, a viewgraph projector) that are nearby

  12. Low-tier wireless systems • use radio to connect a telephone handset to a base station that is connected via a wireline network to a telephone company • designed mainly to serve users with pedestrian-moving speeds • the coverage ranges of such low-tier base stations are less than 500m outdoors and less than 30m indoors

  13. Low-tier standards • Cordless Telephone, Second Generation (CT2) • Digital European Cordless Telecommunications (DECT) • Personal Access Communications Systems (PACS) • Personal Handyphone System (PHS) • CT2 and DECT primarily are used as wireless extensions of residential or office telephones • PACS and PHS operate in public areas and provide public services

  14. 1.1.1 Wireless Local Area Networks • WLAN • provides a shared radio media for users to communicate with each other and to access an IP network, e.g., • Internet • enterprise network • Internet Service Provider • Internet Application Provider

  15. uses the unlicensed Industrial, Scientific, and Medical (ISM) radio frequency bands • in the U.S., the ISM bands include • 900-MHz band (902–928 MHz) • 2.4-GHz band (2400–2483.5MHz) • 5.7-GHz band (5725–5850MHz)

  16. IEEE 802.11, the most widely adopted WLAN standard around the world, consists of a family of standards that defines • physical layers (PHY) • Medium Access Control (MAC) layer • WLAN network architectures • how a WLAN interacts with an IP core network • the frameworks and means for supporting security and QoS over a WLAN

  17. IEEE 802.11 • defines the MAC and different physical layers based on radio frequency (RF) and Infrared (IR) • Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) operating in the 2.4-GHz ISM band are specified for the RF physical layer • the DSSS PHY provides 2Mbps of peak rate and optional 1Mbps in extremely noisy environments

  18. the FHSS PHY operates at 1Mbps with optional 2 Mbps in very clean environments • the IR PHY supports both 1Mbps and 2Mbps for receiving, and 1Mbps with an optional 2Mbps bit rate for transmitting

  19. IEEE 802.11b • defines a physical layer that provides data rates up to 11Mbps in the 2.4-GHz ISM radio frequency band • IEEE 802.11b is the most widely deployed WLAN today • IEEE 802.11a • defines a physical layer that supports data rates up to 54 Mbps using the 5.7-GHz ISM radio frequency band

  20. IEEE 802.11g • defines an extended rate physical layer to support data rates up to 54Mbps using the 2.4-GHz ISM radio frequency band • IEEE 802.11i • defines a framework and means for supporting security over IEEE 802.11 WLANs

  21. IEEE 802.11e • defines a framework for supporting QoS for delay-sensitive applications (e.g., real-time voice and video) over IEEE 802.11 WLANs • IEEE 802.11f • defines the Inter Access Point Protocol (IAPP) to assure interoperability of multi-vendor access points

  22. WLANs support an increasingly broader range of mobile applications • Enterprise WLANs • WLANs are now widely used in enterprise networks to provide wireless data services inside buildings and over campuses or building complexes

  23. Commercial Public WLANs • WLANs are being deployed rapidly around the world to provide public wireless services • Public WLANs • deployed in train stations, gas stations, shopping malls, parks, along streets, highways, or even on trains and airplanes

  24. used to provide mobile Internet services to business travelers and consumers • used to provide customized telematics (telecommunication + informatics) services to people inside moving vehicles and to in-vehicle computers that monitor or control the vehicles

  25. Wireless Home Networks • WLANs started to be used in private homes to replace wired home networks

  26. 1.1.2 Public Wide-Area Wireless Networks • Public (commercial) wide-area wireless networks • provide public mobile services over large geographical areas to users moving on both pedestrian and vehicular speeds • A commercial wide-area wireless network typically consists of • Radio Access Network (RAN) • Core Network

  27. Radio Access Networks (RAN) or Radio Systems • provides radio resources (e.g., radio channels) for mobile users to access a core network • consists of wireless base stations, each providing radio coverage to a geographical area called a radio cell or cell

  28. example • a radio cell in a wide-area network may exceed 10km in diameter • multiple cells may be deployed to provide continuous radio coverage over an entire country or beyond • radio cells are typically arranged in a cellular formation to increase radio frequency reusability • wide-area radio systems are commonly referred to as cellular systems

  29. Core Network • typically a wireline network used to interconnect RANs and to connect the RANs to other networks such as the PSTN and the Internet

  30. 1.1.2.1 1G, 2G, and 2.5G Wireless Networks • 1G • Advanced Mobile Phone Systems (AMPS) in North America • Total Access Communications Services (TACS) in the United Kingdom • variants of TACS include ETACS, JTACS, and NTACS • Nordic Mobile Telephone (NMT) in Nordic countries

  31. 2G • in North America • IS-136 for Time Division Multiple Access (TDMA) radio systems • IS-95 for Code Division Multiple Access (CDMA) radio systems

  32. in Europe • GSM (Global System for Mobile communications) • 900-MHz and 1800-MHz radio frequencies in Europe • 800 MHz and 1900MHz in the United States • in Japan • Personal Digital Cellular (PDC)

  33. 2.5G • General Packet Radio Services (GPRS) • Enhanced Data Rates for Global GSM Evolution (EDGE)

  34. 3G • significantly increase radio system capacities and per-user data rates over 2G systems • 3G radio systems promise to support data rates • up to 144Kbps to users moving up to vehicular speeds • up to 384 Kbps to users moving at pedestrian speeds • up to 2 Mbps to stationary users

  35. support IP-based data, voice, and multimedia services • the objective is to achieve seamless integration between 3G wireless networks and the Internet so that mobile users can access the vastly available resources and applications on the Internet

  36. enhance QoS support • 3G systems seek to provide better QoS support than 2G systems • 3G systems are designed to support multiple classes of services, including, for example, • real-time voice • streaming video • non-real-time video • best-effort data

  37. improve interoperability • achieve greater degree of interoperability than 2G systems to support roaming among • different network providers • different radio technologies • different countries

  38. Two international partnerships define 3G wireless network standards • Third-Generation Partnership Project (3GPP) • 3GPP seeks to produce globally applicable standards for a 3G mobile system based on evolved GSM core networks and the radio access technologies

  39. 3G core networks • evolve the GSM core network platform to support circuit-switched mobile services • evolve the GPRS core network platform to support packet-switched services • 3G radio access technologies • base on the Universal Terrestrial Radio Access Networks (UTRANs) that use Wideband-CDMA (WCDMA) radio technologies

  40. Third-Generation Partnership Project 2 (3GPP2) • 3GPP2 seeks to produce globally applicable standards for a 3G mobile system based on evolved IS-41 core networks

  41. 3G core networks • evolve the IS-41 core network to support circuit switched mobile services • define a new packet core network architecture that leverage capabilities provided by the IS-41 core network to support IP services • 3G radio access technologies • base on cdma2000 radio technologies

  42. WCDMA • uses two modes of Direct Sequence CDMA (DS-CDMA) • Frequency Division Duplex (FDD) DS-CDMA • Time Division Duplex (TDD) DS-CDMA

  43. with DS-CDMA • each user’s traffic is spread by a unique pseudo-random (PN) code into pseudo noises over the same radio frequency band • the receiver uses the exact pseudo-random code to unscramble the pseudo noise to extract the user traffic

  44. Footnote：Scramble • In telecommunications, a scrambler is a device that transposes or inverts signals or otherwise encodes a message at the transmitter to make the message unintelligible at a receiver not equipped with an appropriately set descrambling device • Whereas encryption usually refers to operations carried out in the digital domain, scrambling usually refers to operations carried out in the analog domain

  45. Scrambling is accomplished by the addition of components to the original signal or the changing of some important component of the original signal in order to make extraction of the original signal difficult • Examples of the latter might include removing or changing vertical or horizontal sync pulses in television signals; televisions will not be able to display a picture from such a signal • Some modern scramblers are actually encryption devices

  46. In telecommunications and recording, a scrambler (also referred to as a randomizer) is a device that manipulates a data stream before transmitting. The manipulations are reversed by a descrambler at the receiving side

  47. FDD and TDD refer to the methods for separating uplink traffic (from mobile to network) from downlink traffic (from network to mobile) • FDD uses different frequency bands to transmit uplink and downlink traffic (2110–2170MHz for downlink and 1920–1980MHz for uplink) • TDD uses the same frequency band for both uplink and downlink transmissions, but it schedules uplink and downlink transmissions in different time slots

  48. Cdma2000 • uses Frequency Division Multiplexing (FDM) Multicarrier CDMA (MC-CDMA) • a single carrier in cdma2000 uses a Radio Transmission Technology (RTT) that provides data rates up to 144 Kbps • a cdma2000 system that uses a single carrier is referred to as cdma2000 1xRTT

  49. three carriers may be used together to provide data rates up to 384 Kbps • a cdma2000 system using three carriers is commonly referred to as cdma2000 3xRTT

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