Tutorial #18 - Personal Area Networks

1. Other than speed, detail some of the major differences between USB and IEEE 1394.
2. In a USB network all communication is controlled by a host controller and all data is transferred via the host controller (no direct communication can occur between functions). Discuss the advantages and disadvantages with this approach.
3. USB frames contain a packet type identifier (PID) followed by the compliment of the same PID. Why is this done? Doesn't it just waste bits?
4. IEEE 1394 provides for isochronous transfers. What is this and why would it be beneficial?
5. An IEEE 1394 cycle is nominally 125µs in length. Assuming that the bus is operating at 800Mbps, how many bits will be transferred in each cycle?
6. Bluetooth devices can use a transmit power of 1mW - 100mW. Devices capable of transmitting at higher power must implement "power control". How does this work and why is it necessary?
7. One of the nice aspects of IEEE 1394 is that of automatic configuration. What processes are used in order to achieve this?
8. The original IEEE 1394 can operate at up to 400Mbps, whereas the USB 2.0 Highspeed standard operates at 480Mbps. However, in most cases IEEE 1394 would achieve better performance than USB. What would cause this?
9. Ultra-Wideband (UWB) uses all or part of the frequency spectrum from 3.1GHz to 10.6GHz, resulting in a bandwidth of up to 7.5GHz. Given that other devices may be operating in this "licensed" spectrum, how can UWB work without causing interference?
10. What is MB-OFDM? Provide a very basic overview of how this works.
11. What conclusions could you draw with regards to UWB and Shannon's theorem?
12. Wireless USB (WUSB) supports Dual-Role Devices (DRDs). What are DRDs and what advantages do they provide?