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Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National Chiao-Tung University

Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Page 1: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

Ch0:1Tseng:WirelessNet

Chapter 0: OverviewWireless Network Architecture

&Potential Research Directions

Yu-Chee Tseng

Dept of Computer Science

National Chiao-Tung University

Page 2: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

Ch0:2Tseng:WirelessNet

Page 3: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

Ch0:3Tseng:WirelessNet

Wireless Network Models

With Infrastructure: Without Infrastructure (ad hoc networks):

Page 4: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Cellular: Infrared:

Page 5: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

Ch0:5Tseng:WirelessNet

As relaying link Packet Radio Network

Page 6: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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無線隨意網路( Multi-hop Ad Hoc Network )

Laptop

PDA

LaptopLaptop

Laptop

A

B

C

D

E

PDA

Laptop

Laptop

Laptop

PDA

PDA

C'

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感測網路( Sensor Network )

Page 8: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Nokia Rooftop Product

Page 9: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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2.3 GHz

900 MHz

Modem

Wired Access Point

PoletopRadio

2.4 GHz

High-speed dedicated wired

connections

Internet and Corporate Networks

Network InterfaceFacility

The Ricochet Network Overview

Page 10: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Easy Installation

Page 11: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Bluetooth Technology

bluetooth headset bluetooth dongle

bluetooth MP3 watch bluetooth remote car control

Page 12: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Research Directions:

Mobile Computing, Communications, and MEMS Technologies

Page 13: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Three Directions Together

Wireless Communication Technology

Portable Computer Technology appearance of light-weight computing devices

MEMS Technology 微機電系統 (Micro Electro Mechanical Systems , MEMS) ,其定義

為一個智慧型微小化的系統,包含感測、處理或致動的功能,包含兩個或多個電子、機械、光學、化學、生物、磁學或其他性質整合到一個單一或多晶片上。其應用領域極為廣泛,包括製造業、自動化、資訊與通訊、航太工業、交通運輸、土木營建、環境保護、農林漁牧等。

Vision: Ubiquitous/ Nomadic Computing, communication, and control computers everywhere; information anywhere anytime control

Page 14: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Features of Wireless Communication

one global bandwidth shared by all users fortunately channels, such as (frequency, time-slot) pairs, can be

reused Radio-based

low bandwidthhigh latency radio communication linkshigher bit error rate (BER)

fading short-term multipath fading (Rayleigh effect)

due to same signal taking different paths and arriving at the receiver shifted in phase

long-term fading (radio shadow) topology of the terrain (like mountains) can cause signal dropouts

Page 15: Ch0:1 Tseng:WirelessNet Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National

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Features of Portable Computers

Limited resources: limited energy (battery life) limited CPU speed limited memory limited display

Mobile Applications/ServicesPico-service: local parking lot availability, layout of a building Micro-service: train and bus station informationMacro-service: weather information, news service, stock market in

formation Real-time multimedia applications

tele-medicine collaborative working environment

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Features of MEMS

MEMS (Micro Electro Mechanical Systems) are the integration of electrical devices and mechanical structures at the micrometer (10-6 m = 0.000001 m) scale. The essence of MEMS is their ability to perform and enhanc

e tasks, in ways and in the micro world, impossible using conventional technologies.

digital propulsion Microthruster

optical switchsegway

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Research: Hardware Aspects

power saving display, LCDlow-voltage CPUs

Example: AT&T's Hobbit chip: 5,000 times less power consumption in doze mode than active mode

radio: an example of IEEE 802.11 power consumption transmit: 1400 mW receive: 1000 mW idle: 830 mWsleep: 130 mW

“transmitting 1 bit is equal to executing > 1000 instructions

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Research: Software Aspects

mobile communication protocolsWAPwireless TCPMobile IPMAC protocols

Energy-efficient protocolrelated to the above send/receive/idle/sleep model

Mobile Operating Systems:Windows Mobile, Android, etc.

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Research: Application Aspects

Compute, communicate, and micro-control Context-aware computing

context includes user's location environment (e.g., noise level, communication b/w,

communication cost etc.)social situation (e.g., with boss, with co-worker etc.)

context-aware applicationscontext-sensitive information access (e.g. where are the

bookstores in the vicinity)context-sensitive commands: in active badge system

command format: <badge> <location> <event-type> <action> Ex: Coffee Kitchen arriving “play -v 50 ~/sound/rooster.au”