Research On The Performance Of Bluetooth Data Transmission Based On Packet Selection And Hybrid ARQ Algorithm

Bluetooth is a kind of wireless communication technology which is widly applied.Bluetooth products are used everywhere in our life such as headphones and householdequipment. In order to meet the needs of the market, Bluetooth technology developsconstantly. From the earliest1.0version to the latest4.0version of2010, Bluetooth standardis evolving and developing.Bluetooth technology has always been the focus for the researchers. There are still a fewof problems which are about Bluetooth data transfer need to be studied. In the baseband layer,Bluetooth can show different characteristics during transmission, because there are manydifferent types of packet. Which is the most suitable type for the current channel condition isalso worth studying. So many literatures of different packet types selection algorithm havebeen put forward. In the logical link control and adaptation layer, retransmission method hasthe important influences on the efficiency of the transmission. Due to the stipulated algorithmin the agreement is Go-Back-N protocol, the algorithm is not only inefficient, but also takes alot of cache space, therefore it is not suitable for application. Some researchers have proposeda few improvements of the retransmission algorithm.In order to improve the data transmission performance of Bluetooth, many algorithmshave been proposed in these two layers, but there is room for research. In the baseband layer,the grouping methods have poor performance, especially when the SNR is low, the performa-nce of the whole system will be affected. In the logical link control and adaptation layer, thecurrent retransmission algorithms are efficient, but conditions relatively strict. So somesystems can not implement, it greatly reduces the usage rate.According to the problem above, in order to improve the transmission performance, thispaper mainly does some researches on these two layers of Bluetooth. The innovation of thework can be concluded in two aspects, as follows:1. Aiming at the existential problem of the baseband layer, this paper puts forward animproved packet selection mechanism. Firstly, SNR estimation algorithm is used to estimatethe state of the current channel, and then the packets can be divided into two cases comparedwith threshold value. If the value is smaller than the threhold, it will be optimized for gettingthe best throughput. For the other situation, it will be sent without doing anything. Finally, we can select the best packet from the two groups. By analyzing the simulation results, we knowthe selection mechanism can improve the performance of Bluetooth system well.2. Aiming at retransmission of the logical link control and adaptation layer, the SR+STalgorithm which has better performance compared with the others is analyzed in this paper.The algorithm is very close to the ideal efficiency of retransmission algorithm, but therealization of sending and receiving is very complex, and the high efficiency of the algorithmis at the expense of cache space. In view of the baseband layer adopts high-performanceselection mechanism, the layer can select different retransmission algorithm in differentsituation without the subject to high efficiency. This paper studies on two kinds ofretransmission algorithm, the first one is adding the SR model based into GBN protocol ofBluetooth standard, and using the logical channel to transmit the error packets. The secondone is to simplify the SR+ST, so that it will be more suitable for the application. Through thesimulation analysis of the two methods, we can find the performance difference is not obviouscompared with the original algorithm, but the applicability is greatly improved. Therefore, theselection mechanism whitch was proposed in this paper can guarantee the performance of thesystem, at the same time it makes us to choose a more suitable retransmission algorithm forthe application.This paper mainly research on the Bluetooth technology, including the characteristics,application, current research situation, and focusing on the current research situation ofBluetooth data transmission at home and abroad. Then we do research into the details ofBluetooth protocol and the data transmission mechanism, and the related algorithms aresimulated. Based on these studies, two innovation points of this paper are put forward. Alongwith the descriptions and analysis of the proposed algorithm, simulation results and analysisare given. Finally, we summarize the main content of this paper, and do some plans for future.