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Advanced Topics in Next-Generation Wireless Networks

Advanced Topics in Next-Generation Wireless Networks

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Advanced Topics in Next-Generation Wireless Networks

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  1. Advanced Topics in Next-Generation Wireless Networks Qian Zhang Department of Computer Science HKUST Introduction of Wireless Networks

  2. Why Wireless? • Convenience and flexible • Mobility • Coverage • Easy to deploy • Low cost • New applications potential • Improved quality of life (people with disabilities) anytime anywhere any device service 4A: Anytime, Anywhere, Any device, and Any service

  3. Fast Growing Devices Create New Connectivity Demands

  4. Wireless Technologies coverage Bluetooth UWB RFID WWAN (3G,4G?) WMAN (Wi-Max) WLAN (Wi-Fi) WPAN

  5. Big Picture – WPAN’s • WPAN technologies – RFID, Bluetooth, UWB • RFID used in tagging applications, restricted environments (supermarkets, institutions) • 10 billion RFID tags been sold by the end of 2005 (source: Deloitte & Touche) • Bluetooth – technology has matured • 56% of mainstream devices commercialised will have Bluetooth support by 2008 (Source: IDC) • UWB: bandwidth larger than 500MHz • Two main camp: DS-UWB (Motolora) vs. MBOA-OFDM UWB (Intel+TI)

  6. Ultra WideBand (UWB) PVRs STBs Mobile CE Cluster HDTV Cluster Cordless Phones VCRs tablets laptops 3G camcorders Console Handsets MP3 audio cameras Games pocketPC systems Projector PDA speakers storage PC devices Cluster printers Scanners

  7. 1999 2001 2003 2005 2007 WLAN (WiFi-802.11x) • Physical Layer • Enhancements 802.11k Radio Resource Measurement 802.11a 802.11e Quality of Service 802.11n 5 GHz 100 Mbps (above MAC) 54 Mbps 802.11b 802.11g 802.11i Enhanced Security 2.4 GHz 2.4 GHz 11 Mbps 54 Mbps

  8. 2005 2006 2008 2007 2004 IEEE 802.16d Air I/F Fixed BWA Approved 07/04 Approval 05/05 Corrigenda (TGh) WiMAX 1st certificate 07/05 Chipset for Indoor-outdoor CPE IEEE 802.16e Air I/F Fixed & Mobile BWA Approval 05/06 Corrigenda (TGh) Approval 07/05 Possible delay Chipset for PCMCIA No handover Chipset for Centrino Handset Big Picture –WMAN’s WiMax (Worldwide Interoperability for Microwave Access) • Standard & Chipset Availability • Intel is the main driver for WIMAX: Integration in Centrino is the disruptive goal

  9. WiFi Airport NB or BTS 2G/3G Feeding WiFi-Hotspot Feeding WiMAX Applications in 2005 IEEE 802.16-2004 WiMAX Base Station Mobile PC/PAD Business, SME, SOHO Access Fixed Services Nomadic PC Residential Fixed WDSL BB Access Campus Hot Zones

  10. WiFi Airport NB or BTS 2G/3G Feeding WiFi-Hotspot Feeding WiMAX Applications in 2006-2007 WiMAX Base Station Mobile PC/PAD Nomadicity, Solutions for Laptops (PCMCIA) Business, SME, SOHO Access IEEE 802.16-2004 & IEEE 802.16e Nomadic PC Residential Fixed WDSL BB Access Campus Hot Zones

  11. WiFi Airport NB or BTS 2G/3G Feeding WiFi-Hotspot Feeding WiMAX Applications in 2007-2008 IEEE 802.16e WiMAX Base Station Mobile PC/PAD Business, SME, SOHO Access Fully Mobile, Integrated Solutions in Laptops and PAD Portable PC Residential Fixed WDSL BB Access Campus Hot Zones

  12. WWAN (3G and Beyond) WMAN (802.16e) OFDM-5MHz (2-6GHz) 15Mbps (60kmph) TD-SCDMA 5MHz 2Mbps Services/Applications WLAN (802.11) 20MHz 54Mbps Harmonized All IP CN UWB (802.15.3a) 7.5GHz (3.1-10.6GHz) 480+Mbps HSDPA 5MHz 10Mbps IP Network Services/Applications MBWA (802.20) OFDM-5MHz (<3.5GHz) 5Mbps (250kmph) CDMA2000 1xEV-DV 1.25MHz 5Mbps WCDMA 5MHz 2Mbps

  13. regional metropolitan area campus-based in-house Overlay Networks - the Global Goal Integration of heterogeneous fixed and mobile networks with varying transmission characteristics vertical hand-over horizontal hand-over

  14. Wireless Networks vs. Fixed Networks • Restrictive regulations of frequencies • Frequencies have to be coordinated, useful frequencies are almost all occupied • Low transmission rates • Local 11~54 Mbit/s, regional currently, e.g., ~40 kbit/s with GPRS/CDMA • Higher loss-rates due to interference • Emissions of, e.g., engines, lightning • Higher delays, higher jitter • Connection setup time with several hundred milliseconds for some wireless systems

  15. Wireless Networks vs. Fixed Networks (Cont.) • Lower security, simpler active attacking • Radio interface accessible for everyone, base station can be simulated, thus attracting calls from mobile phones • Always shared medium • Secure access mechanisms important • Close and complex inter-layer interaction

  16. service location new applications, multimedia adaptive applications congestion and flow control quality of service addressing, routing, device location hand-over authentication media access multiplexing media access control encryption frequency modulation interference attenuation Influence of Wireless Communication to the Layered Model OSI or TCP /IP stack MAY NOT be the way to go! Current Trend :Eliminate layers or introduce hooks such that layers can interact with each other • Application layer • Transport layer • Network layer • Data link layer • Physical layer

  17. Classification of Wireless Networks • Cellular Networks • Organized, base stations that are regularly placed. Mobiles communicate only with base stations • Wireless LANs • Less organized; access points with which mobile nodes communicate • Ad hoc/Multi-hop networks • No infrastructure; nodes potentially move and network dynamically changes • Sensor Networks • application specific; mobility is limited (perhaps to selected subset of nodes); tiny nodes that are resource and energy constrained

  18. Ad Hoc Network Characteristics • Peer-to-peer • Multihop • Dynamic • Low power • Zero-administration • Auto-configured • Autonomous • Really “anytime, anywhere”

  19. Wireless Mesh Networks Most the relay nodes are assumed to be static Key Players: Motorola Nortel Microsoft Intel (802.11s) Meshdynamics Firetide Strix Bellair ….

  20. Possible Applications for Multi-Hop Networks • Emergency response • Military communications • Broadband Internet access sharing • WLAN coverage extension • Home and conference networks • Community networks

  21. The Spectrum Problem All Spectrum May Be Assigned, But … Most Spectrum is Unused Spectrum Dilemma: We are not running out of spectrum; we simply aren’t using it properly!

  22. Overview of Open Spectrum Open spectrum enables opportunistic spectrum access to provide 10x Improvement by reusing wasted spectrum • Primary devices • Utilize assigned spectrum when desired • Movement and channel utilization varies over time • Secondary devices • Seek to utilize remaining “available channels” without interfering primary users • Find optimal balance between maximizing spectrum utilization and minimizing harmful interference Requirement: cognitive radios channels

  23. What is a Cognitive Radio? • Wireless communication radios e.g., 802.11 a/b/g/n, can be described as fixed and adaptive • A fixed radio has its technical characteristics set at the time of manufacturing • An adaptive radio can respond to channel conditions that represent one of a finite set of anticipated events • Cognitive radios • It can dynamically take advantage of spectrum • It provides spectral awareness in support of FCC initiatives in spectral reuse • Can respond intelligently to an unanticipated event, i.e., a channel that it has never encountered before • It can take decisions based on many trained observations

  24. Trends – Industry • Two distinct markets evolve with different technologies and paradigms Local access wireless Wide area wireless • ”Cordless” access • Stationary use • High data rates • Seamless mobility • High speeds • Any-time anywhere • Moderate data rates

  25. Trends – Technology • Increasingly complex and heterogeneous network environment • Many different types of networks, from simple to complex, operated by different types of operators • Many different access technologies - but several of those developed today will not survive • More “niche” wireless standards – no single “4G” radio standard • Gradually shift towards multi-standard “Ambient Networks”

  26. Wide Area Ambient Networks Office Public GPRS Networks Public UMTS Networks WLAN WPAN (BT) Home WLAN & UWB WMAN (WiMAX)

  27. Heterogeneous Systems Fixed Ubiquitous Access WLAN Pervasive Service Dynamic Resource Management WiMAX Different administrative domains Other Access Networks All-IP infrastructure 2.5/3G 4G DAB DVB UWB End-to-end Reconfigurability for Seamless Experience Heterogeneous Environments and Contexts Heterogeneous Devices

  28. Move Forward: Cognitive Networking and System Sense/Aware Automatic Environment Understanding and Dynamic Spectrum Utilization Autonomy Adapt Mistake Correcting Learning