1). Propose an enhancement of IEEE 802.15.4 beacon-enabled mode which adaptively adjusts the active period based on the traffic information
1). Despite its design support for low duty-cycle operation, the fixed superframe size in Beacon-enabled mode limits its capabilities due to two contrasting goals : energy efficiency and higher data troughput
2). PAN coordinator periodically disseminates a superframe structure bounded by a beacon frame into the network and manages its active/inactive period
3). A fixed duration of the active period limits its overall performance by two means : idle listening and lower data throughput
4). A coordinator can adaptively adjust the active period based on the data traffic information of associated devices.
5). The active period is reduced to save energy consumption when a data traffic load is low. Otherwise, the active period will be lenghthen up to the total of beacon interval if a data traffic is higher to increase data troughput.
6). The authors use the term sentinel duration to refer a special period for detecting the traffic information
7). Several occurrences of sentinel duration can be performed in one beacon interval. At the start of a sentinel duration, if a node finds pending data traffic in its queue buffer, it tries to convey the traffic information to its coordinator. When detecting traffic presence from devices at some sentinel duration, the coordinator maintains an active RF state to receive data frames until the next sentinel duration. If there is no data traffic at any sentinel duration, therefore the coordinator and devices can enter maintain the sleep state.
8). Devices can perform the sentinel duration continuously so that the pending data traffics can be transmitted to the coordinator even after the superframe duration is over
9). The sentinel duration (T_SD) can be calculated as T_SD = (2^BE-1) x aUnitBackoffPeriod.
10). If one of the CCA becomes busy during T_SD, traffic indication technique decided that there is data traffic. Otherwise, if no data is generated during T_SD, nodes decide that there is no traffic in this active period and enter into the sleep mode.
1). Using TOSSIM
2). Data frame size : 30 bytes
3). Total simulation time : 200 seconds
4). Only 20% of the nodes generate data frame every 1 second
5). SO = 3 ; BO = 6
6). Number of nodes vs aggregate throughput ; Number of nodes vs Total energy consumption
Performance Improvement of IEEE 802.15.4 Beacon-enabled WPAN with Superframe Adaptation via Traffic Indication. By Zeehan Hameed Mir, Changsu Suh, Young-Bae Ko
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Feb 18, 2009
Taipei City – High Speed Network Lab – Taiwan Tech (NTUST)
Electronics Engineering Polytechnic Institute of Surabaya (EEPIS)