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

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Ch0:3 Tseng:WirelessNet Wireless Network Models  With Infrastructure:  Without Infrastructure (ad hoc networks):

Ch0:4 Tseng:WirelessNet  Cellular:  Infrared:

Ch0:5 Tseng:WirelessNet  As relaying link  Packet Radio Network

Ch0:6 Tseng:WirelessNet 無線隨意網路 （ Multi-hop Ad Hoc Network ）

Ch0:7 Tseng:WirelessNet 感測網路（ Sensor Network ）

Ch0:8 Tseng:WirelessNet Nokia Rooftop Product

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Ch0:11 Tseng:WirelessNet Bluetooth Technology bluetooth headset bluetooth dongle bluetooth MP3 watch bluetooth remote car control

Ch0:12 Tseng:WirelessNet Research Directions: Mobile Computing, Communications, and MEMS Technologies

Ch0:13 Tseng:WirelessNet 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

Ch0:14 Tseng:WirelessNet 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 bandwidth high latency radio communication links higher 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

Ch0:15 Tseng:WirelessNet Features of Portable Computers  Limited resources: limited energy (battery life) limited CPU speed limited memory limited display  Mobile Applications/Services Pico-service: local parking lot availability, layout of a building Micro-service: train and bus station information Macro-service: weather information, news service, stock market information  Real-time multimedia applications tele-medicine collaborative working environment

Ch0:16 Tseng:WirelessNet Features of MEMS  MEMS (Micro Electro Mechanical Systems) are the integration of electrical devices and mechanical structures at the micrometer (10 -6 m = m) scale. The essence of MEMS is their ability to perform and enhance tasks, in ways and in the micro world, impossible using conventional technologies. digital propulsion Microthruster optical switch segway

Ch0:17 Tseng:WirelessNet Research: Hardware Aspects  power saving display, LCD low-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 power consumption  transmit: 1400 mW  receive: 1000 mW  idle: 830 mW  sleep: 130 mW “transmitting 1 bit is equal to executing > 1000 instructions

Ch0:18 Tseng:WirelessNet Research: Software Aspects  mobile communication protocols WAP wireless TCP Mobile IP MAC protocols  Energy-efficient protocol related to the above send/receive/idle/sleep model  Mobile Operating Systems: Windows Mobile, Android, etc.

Ch0:19 Tseng:WirelessNet 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 applications  context-sensitive information access (e.g. where are the bookstores in the vicinity)  context-sensitive commands: in active badge system command format: Ex: Coffee Kitchen arriving “play -v 50 ~/sound/rooster.au”