1. Why Wireless is Different Herb Little Research In Motion

2. Why Wireless? Anytime, Anywhere computing RIM BlackBerry –Give customers access to their own data –Secure corporate email and PIM –Always On, Always Connected

3. Why Wireless is Different Fundamental differences –Bandwidth –Error Rate –Latency and Variability –Power Constraints

4. Wireless Limitations Mobile device Network Regulatory

5. Device Limitations Power consumption –Idle: 300  A –CPU: 10 mA –Receiving: 50 mA –Transmitting: 1700 mA

6. Device Limitations Battery technology –Getting better Power saving protocols –Devices go to sleep for long periods Half duplex vs. Full duplex radios –Turnaround time

7. Device Limitations Transmitter strength vs. Receiver sensitivity –One way coverage CPU cycles –Compression, cryptography Commercial and marketing pressures –Price, form factor, features

8. Network Limitations RF link bandwidth –Bandwidth vs. Transmit power –Bandwidth vs. Error control Mobitex: 8kbps –Shared –1200 baud in file transfer tests

9. Regulatory Limitations FCC, Industry Canada –Allocate spectrum –Responsible for device approval Specific Absorption Rate

10. Wireless vs. Wired Networks User expectations Error rates Throughput –Sensitive to protocol overhead –Compression Latency –Battery saving protocols –SAR

11. Wireless vs. Wired Networks Unknown network connectivity –Out of coverage –One way coverage Battery Life –Avoid chatty applications/protocols –No keep-alive messages

12. Wireless vs. Wired Networks Internet Protocols are typically not optimal for wireless networks –Too chatty –Too much overhead –Timeouts too tight

13. 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