Research On Available Bandwidth And Flow Load-balancing In Wireless Ad Hoc Video Test-bed

With the continues development of wireless Ad hoc network and increase of wireless bandwidth,multimedia transmission in Ad hoc is becoming a new research field.Realtime video traffic requires a route providing enough bandwidth in netwok , called QoS routing. Because 802.11 is a kind of CSMA based transmission media, there exists intra-flow and inter-flow interferences in multi-hop Ad hoc networks, which make the estimation of available bandwidth in these kinds of networks much more difficult. we did lots of experiment about some interfering flow scenary in testbed and found that the affect of interfering flow can be estimated precisely by multiplying a interfer coefficient.Based on the experiment , we make a improvement on the estimation of available bandwidth in the old testbed.Additionally,the unsure ness of transmission route brings to the superposition of routes between different video flows,long qeueing latency and hance the quality of video transmission.so we extends the old route probing mechanism,provides route load probing mechanism. When the superposition takes place,the source nodes of each traffic can sense the change of route load then according to the route load change,the routes initiate a shedule selectively to balance the load of entire network.After enormous experiment on the enhanced testbed , the extended DSR protocol performs better than the old DSR in the aspect of the delivery ratio and end-to-end latency ,which is more appropriate for video transmission.