• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.38-47
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• 2003

Communication between Bluetooth devices is based on TDD by a master unit. In this discipline, the transmission of slave packets can be made only when the master transmits a packet to the slave. Thus, some slots may be wasted when there is no user data in the master's or slave's queue due to the transmission of a POLL or NULL packet. Therefore a scheduling scheme which can minimize the slot waste is required in Bluetooth intra-piconet communication. However, since the master is responsible for the intra-piconet scheduling, it must be provided with an information on each slave's queue length to apply traditional scheduling schemes. which is impossible in Bluetooth. This paper presents a new Bluetooth intra-piconet scheduling scheme that is efficient and does not require the information on each slave's queue length. The scheduling is done based on the information about the existence of data in the master and slave queues which is derived by the master identifying the type of packets transmitted. The master schedules to communicate with the slaves according to the priorities determined based on this information. We Presents simulation results which indicate a significant improvement in the performance when our proposed scheme is used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.467-476
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• 2003

In this paper, we propose an efficient MAC scheduling algorithm for supporting Bluetooth scatternet operations. Our proposed algorithm improves overall performances of scatter mode［2, 3] and considers QoS requirements of each link of the bridge node of a scatternet. Scatter mode is based on time division scheduling and provides every links of a scatternet with fair service opportunities. However, since each Bluetooth devices has various traffic characteristics. fair allocation of service opportunities is not efficient and may cause extravagance of wireless resources. Therefore, we propose a new efficient inter-piconet scheduling algorithm compliant with the current Bluetooth specification［1］, and demonstrate its improved performances via computer simulations.

• The KIPS Transactions:PartA
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• v.14A no.4
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• pp.197-202
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• 2007

This study focused on design and implementation of Mobile 3D Bluetooth Game Engine based on OpenGL-ES. In Mobile 3D network game so far, there is a form the mainstream of wireless inter-net game using WAP and VM. But, VM game we popular because of an excessive communication expense problem for this mobile network game that occur when connect to wireless internet as point out to problem by it, that is, stand-alone game are very popular. This study introduce a mobile 3D Bluetooth Game Engine which is based on mobile 3D standard using OpenGL-ES to solve a problem like mobile network game generally that occur when connect to take pleasure a wireless internet from some people into a short distance. When the number of concurrent packet datum by Bluetooth terminal transfers to each other, we shows that the proposed scheduling scheme for enhancing the process speed up on Bluetooth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2A
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• pp.55-62
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• 2003

This paper proposes an efficient and differentiated MAC scheduling algorithm for Bluetooth systems. The proposed algorithm guarantees QoS (Quality of Service) requirement of each master-slave pair or application. Conventional MAC scheduling algorithms for Bluetooth take priority of each pair into consideration and demonstrate relatively reasonable performance. However, their performances may depend on traffic characteristic, or they are limited by overheads for signaling. In this paper, we propose a new MAC scheduling algorithm superior to the conventional algorithms from the viewpoints of throughput, delay, and supporting QoS. Our proposed algorithm is evaluated via computer simulations under various environments and compared with the conventional scheduling algorithms. Simulation results indicate that the proposed algorithm shows better performance than the existing algorithms, and can support the QoS demand of each pair.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.185-190
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• 2003

Bluetooth communication is based on piconet, which is composed by one master and maximum seven slaves. Several piconets can be interconnected via an inter-piconet Bluetooth unit called a bridge unit to form a Bluetooth scatternet. This bridge node can make its presence in each piconet by switching. This switching must be carefully scheduled so that slot wastage and, hence, packet delays are minimized. In this paper, we introduce an efficient inter-piconet scheduling scheme based on sniff mode. This scheme tries to minimize the wastage of slots by having the bridge unit sniff with its peering masters with time limits and communicate with its slaves in remaining slots. The sniff time limits are determined adaptively based on the amount of traffic in each piconet. Simulation results show this scheme outperforms round-robin scheme based on sniff intervals of equal lengths.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.418-425
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• 2002

Bluetooth is an emerging technology expected to provide users with short range, low cost, pico-cellular wireless connectivity. The access to the medium for Bluetooth is based on a Master driven Time Division Duplexing (TDD) scheme. A slave transmits packets in the reverse slot only after the master polls the slave (or transmits a packet to the slave) in a forward slot. The master transmits packets to a slave in even slots while the slave transmits packets to the master in an odd slot. The way in which the master schedules packets transmission to slaves or polls them determines system performance. In this paper. we propose a traffic adaptive MAC scheduling scheme for Bluetooth. The proposed scheme adopts the ISAR (Intelligent Segmentation and Reassembly) policy, which adjusts the packet size to the traffic patterns, to adapt the polling frequency to the traffic conditions. Also for achieving fairness among master-slave connections our scheme includes a priority policy assinging prioritised service tlimes to each connection. By considering a scenario where a Bluetooth master is used as wireless access point to the Internet, we show that our scheme improve the system throughput and average queue delay with regard to a naive Round Robin (RR) scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9A
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• pp.702-709
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• 2003

In this paper, we propose an efficient and QoS-aware MAC scheduling algorithm for Bluetooth, which considers both throughput and delay performance of each Master-Slave pair in scheduling decisions, and thus, attempts to maximize overall performance. The proposed algorithm, MTDPP (Modified Throughput-Delay Priority Policy), makes up for the drawbacks of T-D PP (Throughput-Delay Priority Policy) proposed in [6] and improves the performance. Since Bluetooth employs a master-driven TDD based scheduling algorithm, which is basically operated with the Round Robin policy, many slots may be wasted by POLL or NULL packets when there is no data waiting for transmission in queues. To overcome this link wastage problem, several algorithms have been proposed. Among them, queue state-based priority policy and low power mode-based algorithm can perform with high throughput and reasonable fairness. However, their performances may depend on traffic characteristics, i.e., static or dynamic, and they require additional computational and signaling overheads. In order to tackle such problems, we propose a new scheduling algorithm. Performance of our proposed algorithm is evaluated with respect to throughput and delay. Simulation results show that overall performances can be improved by selecting suitable parameters of our algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.613-619
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• 2003

Bluetooth is a communication technology enabling short-range devices to be wirelessly connected. A master and one or more slave devices are connected to form a piconet, and piconets are joined to form a scatternet. The units participating in two or more piconets in a scatternet, is called bridge or gateway nodes. In order to operate the scatternet efficiently, both piconet scheduling for the master and slaves of a piconet, and scatternet scheduling for the bridge nodes are playing important roles. In this paper, we propose a traffic-adaptive dynamic scatternet scheduling algorithm based on rendezvous points and rendezvous windows. The performance of the proposed algorithm is compared and analyzed with that of a static scheduling algorithm via simulations. Simulation results show that our algorithm can distribute wireless resources efficiently to bridge nodes depending on the traffic characteristics.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.555-562
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• 2004

We consider differentiated bandwidth allocation for a piconet in short-range wireless personal network systems : Bluetooth. Since bandwidth requirements nay vary among applications/services, and/or it may change over time, it is important to decide how to allocate limited resources to various service classes to meet their service requirements. We propose a simple and efficient bandwidth allocation mechanism which meets bandwidth requirements of various service types while saving power consumption by a Power saying mode, i.e., sniff node. We compare our proposed mechanism with a conventional (weighted) round-robin polling scheme and show that it achieves significant improvement of hroughput, delay, and power consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.841-851
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• 2014

Wireless technologies sharing the same frequency band and operating in the same environment often interfere with each other, causing severe decrease in performance. In this paper, we propose a algorithm based on traffic scheduling techniques that mitigate interference between different wireless systems operating in the 2.4-GHz industrial, medical, and scientific band. In particular, we consider IEEE 802.11 wireless local area networks (WLANs) and Bluetooth data transfer, showing that the proposed algorithms can work when the two systems are able to exchange information as well as when they operate independently of one another. Results indicate that the proposed algorithm remarkably mitigate the interference between the WLAN and Bluetooth technologies at the expense of a small additional delay in the data transfer.