Ch0:1 Tseng:WirelessNet Chapter 0: Chances of Wireless Communications Yu-Chee Tseng Dept of Computer Science and Information Engr. National Chiao-Tung University

Ch0:2 Tseng:WirelessNet Wireless Network Architectures

Ch0:3 Tseng:WirelessNet

Ch0:4 Tseng:WirelessNet Wireless Network Models  With Infrastructure:  Without Infrastructure (ad hoc networks):

Ch0:5 Tseng:WirelessNet  Cellular:  Infrared:

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 Bluetooth Technology

Ch0:9 Tseng:WirelessNet Applications of Wireless Communications

Ch0:10 Tseng:WirelessNet Mobile Computing  Wireless Communication Technology  Portable Computer Technology appearance of light-weight computing devices  Vision: Ubiquitous Computing / Nomadic Computing computers everywhere; information anywhere anytime

Ch0:11 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  solution: deploying multiple antenna sites

Ch0:12 Tseng:WirelessNet Features of Portable Computers  Limited resources: limited energy (battery life) limited CPU speed limited memory  Less reliable, less secure

Ch0:13 Tseng:WirelessNet Mobile System Architecture  Cellular-based  Ad hoc  Relaying link  Wireless ATM  Packet Radio Network  Sensor Networks

Ch0:14 Tseng:WirelessNet Mobile Computing Applications/Services  Wireless information services: Pico-service: local parking lot availability, layout of a building Micro-service: train and bus station information, local traffic information Macro-service: weather information, local news service Wide Area Service: stock market information  Real-time multimedia applications tele-medicine tele-computing collaborative environments

Ch0:15 Tseng:WirelessNet Research: Hardware Aspects  power saving display, LCD low-voltage CPUs  AT&T's Hobbit chip: 5,000 times less power consumption in doze mode than active mode radio:  IEEE power consumption example: transmit: 1400 mW receive: 1000 mW idle: 830 mW sleep: 130 mW  size, user interface (wearable computers)

Ch0:16 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 ... and many others

Ch0:17 Tseng:WirelessNet Research: Algorithmic Aspects  Bandwidth saving  Data caching for broadcast  channel allocation  communication scheduling  math. analysis