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Why Wireless is Different. Herb Little Research In Motion. Why Wireless?. Anytime, Anywhere computing RIM BlackBerry Give customers access to their own data Secure corporate email and PIM Always On, Always Connected. Why Wireless is Different. Fundamental differences Bandwidth
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Why Wireless is Different Herb Little Research In Motion
Why Wireless? • Anytime, Anywhere computing • RIM BlackBerry • Give customers access to their own data • Secure corporate email and PIM • Always On, Always Connected
Why Wireless is Different • Fundamental differences • Bandwidth • Error Rate • Latency and Variability • Power Constraints
Wireless Limitations • Mobile device • Network • Regulatory
Device Limitations • Power consumption • Idle: 300 A • CPU: 10 mA • Receiving: 50 mA • Transmitting: 1700 mA
Device Limitations • Battery technology • Getting better • Power saving protocols • Devices go to sleep for long periods • Half duplex vs. Full duplex radios • Turnaround time
Device Limitations • Transmitter strength vs. Receiver sensitivity • One way coverage • CPU cycles • Compression, cryptography • Commercial and marketing pressures • Price, form factor, features
Network Limitations • RF link bandwidth • Bandwidth vs. Transmit power • Bandwidth vs. Error control • Mobitex: 8kbps • Shared • 1200 baud in file transfer tests
Regulatory Limitations • FCC, Industry Canada • Allocate spectrum • Responsible for device approval • Specific Absorption Rate
Wireless vs. Wired Networks • User expectations • Error rates • Throughput • Sensitive to protocol overhead • Compression • Latency • Battery saving protocols • SAR
Wireless vs. Wired Networks • Unknown network connectivity • Out of coverage • One way coverage • Battery Life • Avoid chatty applications/protocols • No keep-alive messages
Wireless vs. Wired Networks • Internet Protocols are typically not optimal for wireless networks • Too chatty • Too much overhead • Timeouts too tight
Summary • Wireless is different • Internet protocols are not optimal for wireless networks • Efficient applications can be achieved • understand the device and network limitations • tailor solutions