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

2. Ch0:2 Tseng:WirelessNet

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

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

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

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

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

8. Ch0:8 Tseng:WirelessNet Nokia Rooftop Product

9. Ch0:9 Tseng:WirelessNet

10. Ch0:10 Tseng:WirelessNet

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

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

13. 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

14. 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

15. 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

16. 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 = 0.000001 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

17. 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 802.11 power consumption  transmit: 1400 mW  receive: 1000 mW  idle: 830 mW  sleep: 130 mW “transmitting 1 bit is equal to executing > 1000 instructions

18. 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.

19. 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”