Energy-Efficient Traffic Scheduling in IEEE 802.15.4 for Home Automation Networks

Energy-Efficient Traffic Scheduling in IEEE 802.15.4 for Home Automation Networks

Reference :
Energy-Efficient Traffic Scheduling in IEEE 802.15.4 for Home Automation Networks by Hyung Seok Kim, Joo-Han Song, Seo Lee.

The IEEE 802.15.4 low rate wireless personal arena network is a protocol suitable for wireless sensor networks. There has been growing interest in the IEEE 802.15.4 protocol in the home automation networks. The authors propose a scheduling scheme obtaining optimal parameters regarding the IEEE 802.15.4 frame and subframes in the home automation networks
Guaranteed time slots (GTS) are exploited for the delivery of home automation traffic. Given a set of requirements for bandwidths and periods assigned to nodes in the networks, the beacon interval and the active/inactive subframe duration satisfying the requirements are selected considering the low duty cycle by the proposed scheme. Based on these parameters, analityc results provide the way to efficient use of network resources including energy.

Home networks enable communication for home automations such as light contril, home robots, PC peripherals, security, monitor and control of home appliances, doors, locks, remote controllers, heating, ventilation and air conditioning (HAVC),etc.

This paper proposes a scheme to guarantee real-time constraint with low energy consumption. It also requires neither additive overhead nor modification of the standard.

Overview of IEEE 802.15.4 :

The structure of superframe is described by the values of beacon order(BO) and superframe order(SO). BO describes the interval at which the coordinator shall trasmit its beacon frames. The value of BO, and the beacon interval(BI) are 0 <= BO <=14, BI = aBaseSuperframeDuration x 2^BO symbols. The value of SP shall be ignored if BO = 15. So describes the length of the active portion of the superframe, which include the beacon frame.
The value of SO, and the superframe duration (SD) are 0 <= SO <= BO <= 14, SD = aBaseSuperframeDuration x 2^SO symbols.

The active portion od each superframe shall be divided into aNumberSuperframeSlots equally spaced slots of duration 2^SO x aBaseSlotDuration and is composed of three parts : a beacon, CAP and CFP.
The CAP shall start immediately following the beacon and reach completion before the beginning of the CFP on a superframe slot boundary. If the CFP is of zero length, the CAP shall complete at the end of the superframe.The CAP shall be at least aMinCAPLength (=440) symbols.
A device transmitting within the CAP shall ensure that its transaction is complete, including the reception of any acknowledgment, one inter-frame spacing (IFS) period before the end of the CAP. If this is not possible, the device shall defer its transmission until the CAP of the following superframe.

CFP start immediately following CAP. The CFP grow or shrink depending on the total length of all of the combined GTSs. A device transmitting in the CFP ensures that its transmissions are complete one IFS period before the end of its GTS.

LOW DUTY CYCLE TRAFFIC SCHEDULING :

In home automation systems, traffic between the device and the controller can be classified into two major types, periodic and aperiodic traffic. Period traffic is defined as traffic generated and delivered at every fixed period. Aperiodic traffic has no constraint of periodicity. aperiodic traffic can be divided into alarming packets and control commands.

Determining Symbol and Slot Duration :
The number of symbols Na of the active subframe can be ontained from :
Na = aBaseSuperframeDuration x 2^SO (symbols).
where SO is superframe order and aBaseSuperframeDuration is the nymber of active symbols when the superframe order is equal to zero.
Let see full paper for detail🙂 .

Determining the Beacon Interval and the CFP Slots :
In order to guarantee the real-time operation of nodes with periodic traffic, the beacon interfal of the network should be smaller than, or equal to, the minimum period Pmin among periods of traffic assigned to nodes.
Let see full paper for detail🙂

Evaluation :
Figure

networkhomeautomation.png

Conclusion
This paper has proposed how to determine the parameters on the duration of the IEEE 802.15.4 frame and subframes for a wireless network applied to the field of home automation.

This method uses guaranteed time slots for transmission of real-time periodic traffic, since they can guarantee the time constraint of periodicity by making use of the periodic delivery of the beacon and the frame in IEEE 802.15.4

Reference :
Energy-Efficient Traffic Scheduling in IEEE 802.15.4 for Home Automation Networks by Hyung Seok Kim, Joo-Han Song, Seo Lee.

Note : This resume is created for self-learning only. Author and Publisher hold copyrights
This is my way to understand what Wireless Sensor Network is

February 06 2008,
Taipei City
High Speed Network Lab

Udin Harun

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