WiMAX Evolution. OFDM Orthogonal Frequency Division Multiplexing PHY OFDMA. Image of OFDM. Best Connected Model

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1 Agenda Wireless Networks and Systems Provide latest wireless technology Summary of the class Approach and objectives What we covered and what we did not cover Lecture 10 Summary Mobility & Wireless Vision communication update Non stop demand for the communication 2 WLAN SPOT Bandwidth Latency Delay Any time, any where Never step back to past environment Intelligent, Reconfigurable Clients When is the last time you used dial-up? Over 90% of notebook PC have Wireless LAN interface Last missing environment : MAN We have LAN and WAN. LAN < MAN < WAN Seamless access to all networks, apps, & services 3 WAN,MAN,LAN,PAN Convergence Vision All computing devices communicate All communication devices compute 4 Any Time, Anywhere, Any Device WAN LAN MAN PAN All enabled by silicon Demand * 3G WCDMA GPRS EDGE COMPUTING WiWi Broadband <300ft. UWB RFID/ and TAG Bluetooth COMMUNICATIONS User can select: Optimal Connectivity Innovation 5 6 owners. 1

2 Best Connected Model Evolution Cellular Fixed Wi- Wi- Backhaul Mesh Backhaul Barn Metrozone Urban Rural Suburbs complements wireless LAN and mobile cellular networks Urban 7 Nomadic Portable Metrozone 8 PHY OFDMA All User 1 User 2 User 3 User 4 OFDM Orthogonal Frequency Division Multiplexing Multi-carrier transmission technique Effectively squeezes multiple modulated carriers tightly together, reducing the required bandwidth Keeping the modulated signals orthogonal Do not interfere with each other. Subcarrier Freq. Amp(dB) Freq 9 10 Image of OFDM and Forum Relationship Original signal spectrum 2/T 1/T 1/T 1/T fc Multiplexed signal using OFDM technique IEEE WG (Air Interface Standards) PICS (Protocol Implementation Conformance Statement) h License- Exempt (REVd) Fixed BWA Specification OFDM-256 PHY f Fixed Access MIBs g Procedures e Amendment Specification for Combine Fixed & Operation Scalable OFDMA PHY Interoperability Profiles TSS/TP (Test Suites Structure & Test Purposes) Fixed Access Nomadic/Portable/ Access 11 In Process Being Planned Being Developed 12 2

3 Protocol Stack Convergence Sublayer Packet IP Ethernet ATM Classifiers Header Suppression E2E Architecture Internet PSTN Network Entry ARQ Single Carrier (10-66GHz & <11 GHz) PDU Generation Privacy & Key (PK, EAP, AES, Multicast Security) MAC Layer PDU Reassembly OFDM-256 FFT, AAS (<11GHz) PHY Burst Scheduling PHY Layers Connection Handoffs OFDMA ( <11GHz) BW Power (Sleep & Idle Modes) 2048 FFT mode, Subchannelization schemes, H-ARQ, AAS, MIMO, STC) Scalable 128, 512, 1024 FFT modes (<6GHz) e 13 MSS Fixed SS Subscriber Nodes RAN IP Cloud Network Access Well defined functional interfaces Media Gateway Operator Core Network Network Service Apps And Services Application Service Private Intranets 14 Strategy Status One standard for wireless broadband connectivity Drive harmonization - one global system Licensed & license-exempt spectrum reform New business opportunities for portable & mobile broadband services New solution for emerging & rural markets is getting market acceptance forum membership growth accelerating >400* Over 150* operator trialing and developing Korea launching WiBRO services in Pusan WiBRO services will use Certified Product when available in either late 06 or early * As of November 2005 Toward the Unwired network environment will be deployed in Mixed wireless media communication Combination of 3G*, Wi-,, etc. New usage of wireless communication New equipment New service/business Real ubiquitous environment Anytime, anywhere with Broadband connectivity Summary of the course 17 3

4 Integrated Approach What we covered Characterization Design Applications Middleware Networking Wireless Networks Topics Location and Context Aware Pervasive Computing Middleware Client-server computing Peer-to-peer and ad hoc computing Service discovery and control ad hoc networks IP Nomadic services Security IEEE and Bluetooth Mobility in wireless LANs Wireless fundamentals Describe the characteristics and operation of contemporary wireless network technologies such as the IEEE wireless local area network and Bluetooth wireless personal area network Lecture 1-3 Describe the operation of the TCP/IP protocol suite in a mobile environment, including the operation of IP and a mobile ad hoc routing protocol IP (lecture 4) OLSR MANET routing protocol (lecture 5) Nomadic support mechanism and TCP characteristics (lecture 6,7) Describe security issues and current solutions for wireless networks and mobile systems IEEE , WPA, and IEEE i (lecture 8) What We Didn t Cover (1) Wireless networks and mobile computing are both huge fields so there are lots of topics that we didn t cover or didn t cover in sufficient depth Communications Physical level modulation and coding schemes Spectrum allocation and utilization Networking Cellular systems Lots of additional protocols Lots of additional complexity What We Didn t Cover (2) Software design issues New environments and languages Power-aware Integrated hardware/software design Lots of additional complexity Hardware design issues Low power Small form factor Efficient reuse of resources Integrated hardware/software design What We Didn t Cover (3) Human computer interaction Design for small displays Gesture and touch recognition Video integration Speech System issues Location detection And lots more! Assignment 1 Build your own network environment using following technologies If you can use WiFi, you must select at least 3 items from followings, WPA technology i technology IP {v4 or v6} DHCP MAC filtering at AP If you can not use WiFI, you must select at least 2 items from followings, 802.1x DHCP IP {v4 or v6} Submit summary of the network such as topology map, configuration file and the test result that show the selected protocol could work

5 Assignment 2 In the WiFi environment, confirm the vulnerability of WEP using WEP analysis tools Procedure 1. Build sample network using WiFi AP 2. Select 40bit and 128bit WEP key 3. Monitor and analyze the traffic 4. Compare the weakness of each keys 5. Change WEP key and check if the weakness would change Caution: Never monitor existing network traffic. Use sample network. You can select monitoring tool depends on your PC environment. Submit the test result as report Assignment 3 TCP window flow control mechanism Monitor the traffic and analyze the windows flow control mechanism Select more than two independent operating system and confirm the TCP performance OS: Windows98,2000,XP,Vista,BSD*,Linux* Procedure Prepare large file to transmit (e.g. 100MB) Transmit the file via TCP (ftp, http,etc) Monitor the change of window size and throughput Make a graph of window size and throughput Analyze the graph and guess which TCP mechanism is implemented Submit a report with graph and analyzed data Assignment 4 Spectrum governance Study the spectrum allocation in your country from 300kHz to 30GHz Study detail spectrum allocation of today and future plan for following usage Cellar phone (2G,3G,4G) WiFi OFDM is getting popular from spectrum efficiency point of view Why OFDM can reduce required bandwidth? Explain the reason using mathematical analysis. Why OFDM is better than CDMA? 27 5