The autors provide mechanism for adaptation of the protocols duty cycle during runtime. They propose BOAA, algorithm for beacon order adaptation in IEEE 802.15.4 star-topology. With decreasing dynamics of the process to monitor, the energy consumption should decrease and lifetime increases respectively. Other researchers considered a multi-hop network with low duty cycle protocol.
They found that with higher numbers of devices and higher arrival rates instabilities can occur. In previous works, the idle listening was identified as a major energy consumtion. The authors reused the idea of monitoring the network, evaluating the data and reconfiguring parameters. The goal is to decrease the energy consumption instead of optimizing delay, throughput and loss rates. The energy consumption can be seen as an additional performance parameter in WSN.
Duty Cycle Organization :
The parameters BO and SO can vary between 0 and 14. The parameter aBaseSuperFrameDuration depends on the frequency range of operation (868/915 MHz or 2.4 GHz), the 2,4 GHz frequency range is assumed which leads to aBaseSuperFrameDuration = 15.36 ms.SO and BO are the key parameters for potential energy savings.
Power vs. Delay :
Changing the beacon order BO leads to an increasing beacon interval BI and therefore to a lover duty cycle with less activity on the medium. On the other hamd, this introduces a delay because a device has to wait until the next beacon initiates the active period where it is allowed to access the medium. The decrease throughput caused by increasing BO is neglected in this paper (for future work).
In creasing the beacon order results in energy saving for the coordinator which is reasonable since less beacons need to be sent and longer durations between the active phases mean less energy consumption. A higher beacon order means more energy saving and higher delay.
Beacon Order Adjustment :
With a higher BO, the time between two successive BO-changes increases. The reason in that the time between two consecutive beacons is longer with increasing BO, therefore the recording of communication over beacon intervals takes longer.
A New Beacon Order Adaptation Algorithm for IEEE 802.15.4 Networks.
By Mario Neugebaer
Note : This resume is created for self-learning only. Author and Publisher hold copyrights
Every Time With Your Love
October 22, 2008
High Speed Network Lab