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Wireless Networks

Wireless Networks

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Wireless Networks

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  1. Wireless Networks Lecture 25 1st Review Dr. Ghalib A. Shah

  2. Last Lecture • Cdma2000 introduction • New MAC and Physical layer features • Physical layer of cdma2000 • Reverse Physical channels • New Network elements in cdma2000 • Packet Control Function (PCF) • Packet Data Serving Node (PDSN) • Mobility Management • Handoff • Intera-PCF • Inter-PCF/Intra-PDSN • Inter-PDSN

  3. Lecture 1 - Introduction Part I • The Wireless vision • Radio Waves • Channel Capacity • Signal-to-Noise Ratio • EM Spectrum

  4. Lecture 1 - Introduction Part II • Wireless Transmission • Baseband signal, carrier frequency, fundamental frequency • antenna size must correspond to signal’s wavelength • 1 MHz signal  few 100 m-s high antenna; • 1 GHz signal  few cm-s high antenna • Encoding/Modulation • Noises • Thermal, Intermodulation, Crosstalk, Impulse • Losses/Gain

  5. Lecture 3 – Introduction Part III • Multiplexing • Transmission Mediums • Guided, Unguided • Propagation modes • Ground wave, Sky wave, LOS • Multi-path propagation • Reflection, Diffraction, Scattering • Fading

  6. Lecture 4 – Error part I • Transmission Errors • Parity Check • Cyclic Redundancy Check • Block Error Code

  7. Lecture 5 – Error part II • Block Codes • Hamming • BCH (Generalization of Hamming) • Reed Solmon (Subclass of non-binary BCH) • ARQ • Sliding window • Go-back-N

  8. Lecture 6 – Multiple Access (Part I) • FDMA • TDMA • CDMA • Random Access • ALOHA • Slotted ALOHA • Reservation-based ALOHA

  9. Lecture 7 – Multiple Access (Part II) • CSMA • Versions of CSMA • CSMA/CA • Spread Spectrum • Frequency Hoping • Direct Sequence

  10. Lecture 8 – Evolution Part I • 1G wireless cellular networks • NMT • AMPS • TACS • 2G cellular systems • GSM • IS-136 • PDC • IS-95

  11. Lecture 9 – Evolution Part II • 2.5G • HSCSD • GPRS • EDGE • IS-95B • 3G • UMTS/W-CDMA • CDMA2000

  12. Specifications of 2.5G and 3G standards

  13. Lecture 10 Evolution III • Limitation of 3G • 4G • Objectives • Issues • QoS • Security • Multimedia Service • Applications • Convergence of Cellular and WLAN • Billing Issue

  14. Quality of Service (QoS) • Traffic generated by the different services will not only increase traffic loads on the networks, but will also require different quality of service (QoS) requirements (e.g., cell loss rate, delay, and jitter) for different streams (e.g., video, voice, data). • Providing QoS guarantees in 4G networks is a non-trivial issue where both QoS signaling across different networks and service differentiation between mobile flows will have to be addressed.

  15. Security • Security in wireless networks mainly involves authentication, confidentiality, integrity, and authorization for the access of network connectivity and QoS resources for the mobile nodes flow. • The heterogeneity of wireless networks complicates the security issue. • Dynamic reconfigurable, adaptive, and lightweight security mechanismsshould be developed. • AAA (Authentication Authorization Auditing) protocols provide a framework for such suffered especially for control plane functions and installing security policies in the mobile node such as encryption, decryption and filtering.

  16. Lecture 11 – Cell Conept part I • Cellular Concept • Frequency Reuse • Locating co-channel cells

  17. Lecture 12 – Cell Concept Part II • Channel Assignment Strategies • Handoff Strategies • When to handoff • 1G, BS based • 2G or todays, Mobile-Assisted • Prioritizing Handoff • Guard channels concept • Queuing handoff requests • Practical handoff considerations • Umbrella cell • Cell dragging

  18. Lecture 13 – Cell Concept Part III • Interference and system capacity • Co-channel interference and capacity • Adjacent channel interference and capacity • Channel Planning for Wireless System

  19. Lacture 14 – Cell Concept Part IV • Trunking and Grade of Service • Measuring Traffic Intensity • Trunked Systems • Blocked Calls Cleared • Blocked Calls Delayed • Erlang Charts • Improving Coverage and Capacity • Cell Splitting • Sectoring • Repeaters for Range Extension • Microcell Zone Concept

  20. Lecture 15 - AMPS • AMPS introduction • System Overview • Call handling • Air interface • Supervisory signals • N-AMPS

  21. Lecture 16 GSM • GSM Introduction • GSM System Architecture • GSM Network Areas • Specifications • Subscriber Services • Mobility

  22. Lecture 17 – GPRS (part I) • Introduction to GPRS • GPRS Architecture • Registration and Session Management • Routing Scenario in GPRS • Channels Classification

  23. PDP Context Activation MS SGSN GGSN Activate PDP Context Request PDP type,PDP Address QoS Requested,Access Point,… Security Functions Create PDP Context Request PDP type,PDP Address QoS Negotiated,Access Point,… Create PDP Context Response Activate PDP Context Accept PDP type,QoS Negotiated,… PDP type,PDP Address QoS Negotiated,…

  24. Lecture 18 – GPRS part II • GPRS Protocol Architecture • MS – BSS • BSS – SGSN • SGSN – GGSN • GGSN – PDN • GPRS Air Interface • Data Routing and Mobility • Uplink Data Transfer • Downlink Data Transfer • QoS in GPRS

  25. Lecture 19 - IS-95 • IS-136 • CDMA/IS-95 • Advantages • Higher capacity, Improves voice quality (new coder), Less power consumption (6-7 mW) • Privacy, graceful degradation • Drawbacks • Self-jamming, near-far problem, • IS-95 Forward Channels • Pilot Channel • Sync Channel • Paging • Traffic • IS-95 Reverse Channels

  26. Lecture 20 - EDGE • EDGE Introduction • Modulation and Coding Schemes • Link Adaptation and Incremental Redundancy • Capacity Planning

  27. Lecture 21 – UMTS / WCDMA part I • UMTS • Service Classes in UMTS • Conversational, Streaming, Interactive, Background • UTRAN Architecture • RNC (Serving, Drifting) • Radio Interface protocol Architecture • Protocol Models for UTRAN • Logical Channels

  28. Protocol Model for UTRAN • UTRAN protocol structure is based this model Trans. Of all user-specific data CS or PS through user plan For all signalling activities in the network, it includes RANAP, RNSAP, NBAP protocols

  29. Lecture 22 - WCDMA Part II • Spreading and Scrambling • Channel Concept • Logical Channel (RLC) ->Transport Channels (MAC)->Physical Channels (PL) • Physical Layer Procedures • RACH Operation (Preamble of 16 symbols and wait for ACK on AICH) • Cell Searching (256 chip primary Synch, 15 SSCs • Power Control • Fast Closed loop (1500 Hz TPC, • Closed Loop

  30. Lecture 23 - WCDMA Part III • Compressed mode measurements • Handover measurements • Intra-mode • Inter-mode • Inter-system • WCDMA packet data access • Transport channels for packet data • Common, dedicated, shared • Packet scheduling algorithms • Time division scheduling • Code division scheduling • Transmission Power-based scheduling

  31. Lecture 24 - CDMA2000 • New MAC and Physical layer features • Physical layer of cdma2000 • Reverse Physical channels • New Network elements in cdma2000 • Packet Control Function (PCF) • Packet Data Serving Node (PDSN) • Mobility Management • Handoff • Intra-PCF • Inter-PCF/Intra-PDSN • Inter-PDSN