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2	Introduction Traffic Balancing Based on reactive routing protocol (can also deployed for proactive routing protocol) Each node records the medium usage around itself and put this information into route request (inrease overThresholdCounter if measured medium usage is over the certain threshold) Sender chooses the path with smallest overThresholdCounter Defect Traffic Balancing verifies if the medium is busy just by the measured medium usage (using a constant threshold)
3	Traffic Balancing and On-demand Routing Protocol
4	Adaptive Traffic Balancing Traffic Balancing determines the medium state only by the percentage of time that the measured signal strength is over the constant threshold Some important issues such as node mobility and congestion state are not considered even though these issues also influence the medium state
5	Adaptive Traffic Balancing As mobility that causes collisions and transmission loss, the measured medium usage under the busy state may vary (backoff period) Examples (5.3 Kbps with packet size of 64 bytes): 0 m/s (max. moving speed) (0.06+0.06+0.32+0.06)/(0.06+0.01+0.06+0.01+0.32+0.01+0.06+0.01)=92.59% 5 m/s (0.06+0.06+0.32+0.06)10/((0.06+0.01+0.06+0.01+0.32+0.01+0.06+0.01)9+(0.06+0.0215+0.06+0.0215+0.32+0.0215+0.06+0.0215))=76.22% Transmission rate is 2 Mbps and it takes around 0.06 ms to transmit a RTS or CTS or ACK. The data packet needs 0.32 ms to be sent and the interframe period is 0.01 ms
6	Adaptive Traffic Balancing The number of collisions that can be seen by a node over a certain period can indicate the node mobility or medium usage condition more precisely than other parameters The faster nodes move, the larger number of collisions can be observed by nodes The larger number of collision happens, the more backoff periods are and less medium usage is detected Method Nodes measure the medium usage and number of collisions over a certain period Based on the number of collisions, a suitable threshold is set
7	Simulation Results Simulation Environment Network Simulator 2 (NS2) IEEE 802.11 MAC Constant Bit Rate Traffic (CBR) at 5.3 Kb/s 100 nodes in a 1000*1000 m² area Implementation of Adaptive Traffic balancing The node checks the number of collisions in the past 2 seconds <10, the medium usage threshold = 0.9 >10 and <50, the medium usage threshold = 0.7 >50, the medium usage threshold = 0.5
8	Simulation Results
9	Conclusion Adaptive Traffic Balancing improves system performance further by dynamically changing the medium usage threshold according to the number of observed collisions The number of collisions partly reflects the node mobility The network state is divided into three levels that limit the benefits of adaptive Traffic Balancing Some other parameters such as bit error rate to reflect the wireless environment need also be included to estimate the network state