Proposed topics of IEEE 802.15.2 AFH ad hoc teleconference to be held on 3rd, May, 2001
Bijan, Hongbing
April 28, 2001
We suggest this time we discuss the advantages of each proposed adaptive hopping mechanism and their applications in various coexistence scenarios.
1.Solutions presented in Hilton Head:
- Still use existing Bluetooth hopping sequence, but whenever meeting a bad channel, replacing it with a good channel.
- Paring of good and bad channels into blocks, reorder Bluetooth hopping sequence using ‘look-ahead algorithm’.
- Bad/good channel pairing, or using same channel for transmitting and receiving.
- Use reduced hopset (say, 23 channels), allocating only good channels to hopset.
- The criterion on how to apply the above mechanisms to various coexistence scenarios and application (say voice oriented, data oriented):
- Legacy devices will inter-operate with new ones in the same piconet
- suggests that it MUST be backward compatible.
- How are broadcast packets (page 71 of Bluetooth specifications v1.1) supported? Requires all devices (including legacy ones) to receive on same channel.
- How is the beacon access window (page 115 of Bluetooth specifications v1.1) supported?
- How are other states supported, Inquiry (Scan), Page (Scan), Sniff, Hold, Park?
- How are scatternet managed?
- Mechanisms need to show some throughput improvement for all networks in area according to some measure
- Minimise complexity of this mechanism
- If the mechanism is too complicated, is it marketable?
- All devices maintain clock synchronisation with Master
- The Link_Supervision_Timeout parameter is used by the master or slave device to monitor link loss. If, for any reason, no packets are received from that Connection Handle for a duration longer than the Link_Supervision_Timeout, the connection is disconnected. (p686 of Bluetooth specifications v1.1)
- Uniform usage of ‘good’ channels;
- Ensures that if one ‘good’ channel goes ‘bad’, we are guaranteed that it will not be overused.
- All devices must know how to re-order/re-map/change the sequence in the same way
- Method should ensure that incorrect mapping does not throw device off network
- Minimise changes/additions to existing standard
- Relates to increasing the ‘saleability’ of this system. Implementers of the Bluetooth standard don’t want a revision that requires too much reworking of the existing product.
- Define minimum number of ‘good’ channels allowed
- Legally now, at high power, minimum is 75 channels?
- Legally now, at low power, minimum is 1 channel?