Bluetooth Scatternet Research Articles

Adaptive inter-piconet scheduling in small scatternets

Inter-piconet scheduling in a Bluetooth scatternet may be performed in an adaptive manner, so as to minimize end-to-end packet delays. Using the theory of queues with vacations, we analyze the impact of different values of scatternet parameters on end-to-end delays, and then investigate the possibility of minimization of the aforementioned delays. We show that such minimization is possible for scatternets with both Slave/Slave and Master/Slave bridges, and that it should be based on inter-piconet traffic. We also describe simple algorithms that enable the scatternet to achieve near minimum delays in a wide range of traffic parameter values.

스니프 모드 기반의 효율적인 블루투스 스캐터넷 스케줄링 기법

블루투스 통신은 한 개의 마스터와 최대 7개의 슬레이브로 구성된 피코넷을 기본 단위로 이루어지며, 다수의 피코넷은 브리지 노드라 불리는 공유 노드를 통해 상호 연결되어 스캐터넷을 형성한다. 브릿지 노드는 스위칭을 통해 피코넷간 통신을 수행하며, 이때 스위칭은 슬롯의 낭비, 즉 패킷 지연 시간을 최소화 할 수 있도록 주의 깊게 스케줄링 되어야 한다. 본 논문에서는 스니프 모드에 기반 한 효율적인 인터 피코넷 스케줄링 기법을 제안한다 스케줄링 기법은 브릿지 노드가 슬레이브로 동작하는 각 피코넷에 대해 스니프 모드를 통해 할당된 통신 시간 중 낭비되는 슬롯을 자신이 마스터로 동작하는 피코넷 통신에 할당함으로써 슬롯의 낭비를 줄인다. 각 피코넷에 할당되는 통신 시간은 트래픽의 양에 따라 적응적으로 결정된다. 실험 결과에 의하면 통신 시간을 균등하게 할당하는 라운드-로빈 기법에 비해 좋은 결과를 보인다. 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.

A Bluetooth scatternet-route structure for multihop ad hoc networks

Bluetooth scatternets, integrating polling, and frequency hopping spread-sprectrum in their medium access control protocol, provide a contention-free environment for Bluetooth devices to access the medium and communicate over multihop links. Currently, most available formation protocols tend to interconnect all Bluetooth devices at the initial network startup stage and maintain all Bluetooth links thereafter. Instead of this big scatternet approach, we propose a scatternet-route structure to combine the formation with on-demand routing, thus eliminating unnecessary link and route maintenances. To the best of our knowledge, this is the first effort to address on-demand formation with every detail. We introduce an extended ID (EID) connectionless broadcast scheme, which, compared with original Bluetooth broadcast mechanism, achieves very much shortened route discovery delay. We also propose to synchronize the piconets along each route to remove piconet switch overhead and obtain even better channel utilization. Furthermore, we present a route-based scheduling scheme to enable fair and efficient packet transmissions over routes. Network performance analysis and simulations show that routes can provide multihop wireless channels with high network utilization and extremely stable throughput, being especially useful in the transmission of large batches of packets and real time data in wireless environment.

Performance of Bluetooth Slave/Slave Bridge

The performance of a Bluetooth scatternet with a Slave/Slave bridge is analyzed using the tools of queueing theory. We analyze two possible scheduling policies: limited service and exhaustive service, and derive analytical results for the probability distribution of access delay (i.e., the time that a packet has to wait before being serviced) and end-to-end delay for both intra- and inter-piconet bursty traffic. The exhaustive service discipline was found to provide lower values for all delay variables, over a wide range of parameter values. All analytical results have been confirmed through simulations.

A new Bluetooth scatternet formation protocol

A Bluetooth ad hoc network can be formed by interconnecting piconets into scatternets. The constraints and properties of Bluetooth scatternets present special challenges in forming an ad hoc networ...

Special issue on innovations in ad hoc mobile pervasive networks

We have seen the convergence of the Internet with mobile telephony. WAP(Wireless Access Protocol) based phones allow mobile phone users to not only make voice calls anytime and anywhere but also the ability to access the Internet and gather required information. However, this “mobile Internet” technology is limited by inferior communication performance. While WAP-based devices are still in existence, a new form of “mobile network” has evolved, known as “ad hoc mobile networks.” We have heard about Bluetooth technology, its piconet and scatternet architectures. However, Bluetooth addresses mostly small devices and requires the presence of one or more master devices. Bluetooth did not define communication architecture beyond scatternet but “ad hoc mobile networks” did.