| Summary: | 碩士 === 義守大學 === 資訊工程學系碩士班 === 93 === Bluetooth is a new short range, low cost wireless access technology. It is developed in order to replace cable. Bluetooth device employs a pseudo-radom frequency-hopping spread spectrum technique to communicate with another Bluetooth device in the 2.4 GHz ISM (Industrial, Scientific and Medical) band. The smallest network unit in Bluetooth is a piconet. There are one master and up to seven slaves in a piconet. The traffic rates of each pair of master and slave are asymmetry in a piconet. In addition, because the influence of the topographical surface feature, there are the phenomenon with path loss and fading. In the paper, we focus on develop an efficient polling algorithm according to master’s and slave’s traffic rates and fading. The algorithm according to dynamically selecting suitable packet’s type and dynamically changing polling interval gets close to the best efficacy for transmitting channel.
We developed an event driven simulator in NS2 and Bluehoc to compare the TRA algorithm and PMP [10] algorithm. The channel is modeled using Rayleigh distribution. Simulation results show that our algorithm can improve the transmitting throughput when the Fading phenomenon of the Fading channel is the more serious and piconet traffic load is heavier.
In the case that distance between master and slave is 1or 3 meters, application layer of the device is CBR, and piconet traffic load (PTL) is larger than 42 Bytes per slot (B/S), the throughput of our algorithm is higher than that of PMP algorithm. When the traffic type is FTP, the traffic rate of master to slave (TRM/TRS) is 1/7 or 7 and PTL is equal to or larger than 42 Bytes per slot (B/S), our algorithm outperforms PMP. When distance between master and slave is 5 meters and PTL is equal to or larger than 42 Bytes/slot, our algorithm’s throughput is higher than PMP algorithm. When distance between master and slave is 6 meters, our algorithm outperforms PMP algorithm.
Our future works include comparing TRA algorithm’s throughput and RRA algorithm’s throughput and want to expand this concept to Scatternet. Let Bluetooth network can have the best transmitting throughput in the Fading channel.
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