Patent ID: 8335155

Claim:
A packet transmission method for a wireless personal area network including a coordinator operating with a specific duty cycle between active periods and inactive, power save periods, the network including a plurality of devices, the method comprising: (a) determining, when a packet is generated in an inactive period, whether there is another packet waiting to be sent; (b) setting, if another packet is waiting to be sent in the inactive period, a backoff time using a binary exponential algorithm, to a value selected randomly in a uniform distribution; (c) setting, if the network is in an active period, the backoff time using the binary exponential backoff algorithm, to the value selected randomly in the uniform distribution; (d) setting, when the network is in the inactive period and no other packet is waiting to be sent, the backoff time to an exponential backoff value determined according to a duty cycle reduction function in which the exponential backoff value decreases from a maximum value to a minimum value as a function of increasing duty cycle between the active periods and inactive, power save periods; and (e) sending the packet when the backoff time has expired.