A Dynamic Bandwidth Allocation Algorithm For Multi-Priority Business Of Bluetooth Piconets

Bluetooth is a kind of short-range wireless communication technology which is widelyused in daily life, healthcare, industrial control and other fields. These scenarios requireinterconnection among multiple Bluetooth devices, so it has always been the researchfocus that determining some Bluetooth device being authorized to access channel, in orderto achieve high efficient data transmission. With application of the Internet of Thingsbecoming more and more wide, the transmission of real-time business among Bluetoothdevices will be common, therefore, when both real-time traffic and non real-time trafficcases occur in Bluetooth piconet, it will be very important to design an efficient and fairscheduling algorithm to guarantee the QoS (Quality of Service) of different businesses.According to the problem above, this thesis presented a dynamic bandwidth allocationalgorithm for multi-priority business in Bluetooth piconet, this algorithm is designed to beable to guarantee the network performance of every link with high priority. The innovationof the work can be concluded in two aspects, as follows:1. An adaptive packet selection strategy was proposed for real-time traffictransmission. To obtain the maximum throughput two qualifications must be satisfied: oneis to choose proper packet according to current channel quality, the other is to make thesending packet full-loaded. In order to satisfied the first qualification, the transmissionperformance of real-time traffic was analyzed based on slots consumption, in order tosatisfied the bandwidth requirement of real-time traffic, the slots which were consumed byvarious packets were computed in different channel quality, then an adaptive packetselection strategy was concluded for transmitting real-time traffic, so the sending node canselect the most proper packet to transmit real-time traffic according to current channelquality so as to occupy the minimum bandwidth resource.2. A dynamic bandwidth allocation algorithm for multi-priority business in Bluetoothpiconet was put forward. Two kinds of priority were defined according to the traffic types:real-time or non real-time, real-time traffic was defined as high priority and non real-timetraffic was defined as low priority.‘The optimal polling interval’ was defined which represents the least interval required before the next polling for one link, theoretically, afterthe optimal polling interval, the data arriving in the buffer can make the sending packetfull-loaded, and at this moment, this link should be polled. The optimal polling interval canbe computed by master according to the selected packet types and the bandwidthrequirement of real-time traffic, so the problem of whether the packet is full-loaded isaddressed. Master determined whether a certain high priority link should be polled bycomparing if the value of its slots counter reached or exceeded the optimal polling interval.If reached, master polled this link, if not, master abandoned polling this link and turned tojudge the next link. Master determined whether a low priority link should be polled byviewing if there is any high priority link to be scheduled. If any of the high priority linkswas scheduled in a polling cycle, master will not poll any low priority links, otherwise,master polled one of low priority links once and the polled link sent one packet, thenmaster continued to execute the next polling cycle. Thus service differentiation mechanismfor different priority traffic in Bluetooth piconet and the QoS guarantee of each highpriority link were provided through this polling rules.Finally, the simulation for the slots which were consumed by various packets in orderto satisfied the bandwidth requirement of real-time traffic was undertaken, an adaptivepacket selection strategy can be deduced from the simulation results. The networkperformance of the dynamic bandwidth allocation algorithm was simulated and thesimulation results shows that the scheduling algorithm can provide bandwidth and delayguarantee for high priority links and can improve the average bandwidth utilization of thewhole piconet.