BlueMesh: Degree-Constrained Multi-Hop Scatternet Formation for Bluetooth Networks

In this paper we describe BlueMesh, a new protocol for the establishment of scatternets, i.e., multi-hop wireless networks of Bluetooth devices. BlueMesh defines rules for device discovery, piconet formation and piconet interconnection so to generate connected scatternets with the following desirable properties. BlueMesh forms scatternets without requiring the Bluetooth devices to be all in each other transmission range. BlueMesh scatternet topologies are meshes with multiple paths between any pair of nodes. BlueMesh piconets are made up of no more than 7 slaves. Simulation results in networks with over 200 nodes show that BlueMesh is effective in quickly generating a connected scatternet in which each node, on average, does not assume more than 2.4 roles. Moreover, the route length between any two nodes in the network is comparable to that of the shortest paths between the nodes.     

蓝牙散射网的构成机制

首先介绍了蓝牙技术的相关知识,然后在此基础上重点讨论了蓝牙散射网的构成机制,最后介绍了散射网的常见结构及性能比较。     

A Location-Aware Routing Protocol for the Bluetooth Scatternet

Bluetooth is a most promising technology for the wireless personal area networks and its specification describes how to build a piconet. Though the construction of scatternet from the piconets is left out in the specification, some of the existing solutions discuss the scatternet formation issues and routing schemes. Routing in a scatternet, that has more number of hops and relay nodes increases the difficulties of scheduling and consumes the bandwidth and power resources and thereby impacts on the performance of the entire network. In this paper, a novel routing protocol (LARP) for the Bluetooth scatternet is proposed, which reduces the hop counts between the source and the destination and reconstructs the routes dynamically using the location information of the Bluetooth devices. Besides, a hybrid location-aware routing protocol (HLARP) is proposed to construct the shortest routes among the devices with or without having the location information and degenerate the routing schemes without having any location information. Experimental results show that our protocols are efficient enough to construct the shortest routing paths and to minimize the transmission delay, bandwidth and power consumption as compared to the other protocols that we have considered. Chih-Yung Chang received the Ph.D. degree in Computer Science and Information Engineering from National Central University, Taiwan, in 1995. He joined the faculty of the Department of Computer and Information Science at Aletheia University, Taiwan, as an Assistant Professor in 1997. He was the Chair of the Department of Computer and Information Science, Aletheia University, from August 2000 to July 2002. He is currently an Associate Professor of Department of Computer Science and Information Engineering at Tamkang University, Taiwan. Dr. Chang served as an Associate Guest Editor of Journal of Internet Technology (JIT, 2004), Journal of Mobile Multimedia (JMM, 2005), and a member of Editorial Board of Tamsui Oxford Journal of Mathematical Sciences (2001--2005). He was an Area Chair of IEEE AINA'2005, Vice Chair of IEEE WisCom 2005 and EUC 2005, Track Chair (Learning Technology in Education Track) of IEEE ITRE'2005, Program Co-Chair of MNSA'2005, Workshop Co-Chair of INA'2005, MSEAT'2003, MSEAT'2004, Publication Chair of MSEAT'2005, and the Program Committee Member of USW'2005, WASN'2005, and the 11th Mobile Computing Workshop. Dr. Chang is a member of the IEEE Computer Society, Communication Society and IEICE society. His current research interests include wireless sensor networks, mobile learning, Bluetooth radio systems, Ad Hoc wireless networks, and mobile computing. Prasan Kumar Sahoo got his Master degree in Mathematics from Utkal University, India. He did his M.Tech. degree in Computer Science from Indian Institute of Technology (IIT), Kharagpur, India and received his Ph.D in Mathematics from Utkal University, India in April, 2002. He joined in the Software Research Center, National Central University, Taiwan and currently working as an Assistant Professor, in the department of Information Management, Vanung University, Taiwan, since 2003. He was the Program Committee Member of MSEAT'2004, MSEAT'2005, WASA'2006, and IEEE AHUC'2006. His research interests include the coverage problems, modeling and performance analysis of wireless sensor network and Bluetooth technology. Shih-Chieh Lee received the B.S. degree in Computer Science and Information Engineering from Tamkang University, Taiwan, in 1997. Since 2003 he has been a Ph.D. Students in Department of Computer Science and Information Engineering, Tamkang University. His research interests are wireless sensor networks, Ad Hoc wireless networks, and mobile/wireless computing.     

Performance Evaluation of Routing Protocols for Ad Hoc Wireless Networks

A mobile ad hoc network is a collection of autonomous mobile nodes that communicate with each other over wireless links. Such networks are expected to play an increasingly important role in future civilian and military settings, being useful for providing communication support where no fixed infrastructure exists or the deployment of a fixed infrastructure is not economically profitable and movement of communicating parties is possible. However, since there is no stationary infrastructure such as base stations, mobile hosts need to operate as routers in order to maintain the information about the network connectivity. Therefore, a number of routing protocols have been proposed for ad hoc wireless networks. In this paper, we study and compare the performance of the following routing protocols AODV, PAODV (preemptive AODV), CBRP, DSR, and DSDV. A variety of workload and scenarios, as characterized by mobility, load and size of the ad hoc network were simulated. Our results indicate that despite its improvement in reducing route request packets, CBRP has a higher overhead than DSR because of its periodic hello messages while AODV's end-to-end packet delay is the shortest when compared to DSR and CBRP. PAODV has shown little improvements over AODV.     

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 network efficiently. In this paper, we present and analyze a new randomized distributed protocol for Bluetooth scatternet formation. We prove that our protocol achieves O(logn) time complexity and O(n) message complexity. The scatternets formed by our protocol have the following properties: (1) any device is a member of at most two piconets, and (2) the number of piconets is close to be optimal. These properties can help prevent overloading of any single device and lead to low interference between piconets. We validate the theoretical results by simulations, which also show that the scatternets formed have O(logn) diameter. As an essential part of the scatternet formation protocol, we study the problem of device discovery: establishing multiple connections simultaneously with many Bluetooth devices. We investigate the collision rate and time requirement of the inquiry and page processes. Our simulation results indicate that the total number of packets sent is O(n) and that the maximum number of packets sent by any single device is O(logn).     

Performance of Bluetooth Bridges in Scatternets with Limited Service Scheduling

The performance of two Bluetooth piconets linked through a bridge device is analyzed using the tools of queueing theory. We analyze both possible cases, i.e., when the bridge device is the master in one of the piconets and a slave in the other (MS bridge), as well as when the bridge device is the slave in both of the piconets (SS bridge). Analytical results are derived 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 scatternet with an SS bridge was found to provide lower end-to-end delay for local traffic as well as lower access delay, while the scatternet with an MS bridge offers lower end-to-end delay for non-local traffic. The scatternet with an SS bridge was also found to be less sensitive to increased probability of non-local traffic and low values of time interval between bridge exchanges, than its counterpart with an MS bridge. All analytical results have been confirmed through simulations.     

Performance Evaluation of Polling Protocols for Data Transmission on Wireless Communication Networks

The growing interest in mobile computing and communication devices leads to the necessity of wireless broadband network. Data transmission over such networks requires suitable error control schemes to guarantee high data reliability as well as efficient bandwidth utilization.In this paper we propose an accurate yet simple analytical approach to evaluate the performance of wireless networks using gated and exhaustive polling protocols combined with the Stop and Wait (SW) or Go Back N (GBN) ARQ schemes [Bertsekas and Gallager, 2]. Moreover, simulation results concerning the performance of polling protocols combined with the Selective Repeat (SR) ARQ scheme are also shown for comparison purposes.Protocol performance is estimated under very general assumptions, such as: AWGN or fading channels, arbitrary value of the round trip delay and arbitrary distribution of the traffic load (i.e., both symmetric or asymmetric system have been considered).     

链形结构的蓝牙分散网拓扑构成算法与性能仿真

提出了一种新的链形结构的蓝牙分散网拓扑构成算法：所有蓝牙节点均以0．5的概率进入查询或查询扫描状态，同时地进行点对点的连接，形成尽可能多的临时皮网，再反复通过各种形式的合并与重组形成更大的皮网与多个皮网形成的组，直至最终形成仅有一个组的链形结构的分散网。仿真与性能分析表明：该算法实现简单，形成的分散网具有较少的皮网数目、较小的各节点角色的平均数与较小的节点最大度数、网络创建时间较短、拓扑动态维护方便、各节点无需均在通信范围内等优点。该算法适用于蓝牙分散网的拓扑构成。     

Performance Evaluation of Bluetooth Polling Schemes: An Analytical Approach

In the recent years, many polling schemes for Bluetooth networks have been proposed and evaluated. To the authors knowledge, however, analysis has been carried out mainly through computer simulations and, up to now, no mathematical treatment of this topic has been presented. In this paper, we propose an analytical framework for performance evaluation of polling algorithms in Bluetooth piconets. The analysis is carried out by resorting to an effective and simple mathematical method, called Equilibrium Point Analysis. The system is modelled as a multidimensional finite Markov chain and performance metrics are evaluated at the equilibrium state. The analysis is focused on three classical polling schemes, namely Pure Round Robin, Gated Round Robin and Exhaustive Round Robin, which are compared in terms of packet delay, channel utilization, and fairness among users. Both analytical and simulation results are presented for three relevant scenarios, in order to validate the accuracy of the analysis proposed.     

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 Fair and Traffic Dependent Scheduling Algorithm for Bluetooth Scatternets

The Bluetooth specification defines the notion of interconnected piconets, called scatternets, but does not define the actual mechanisms and algorithms necessary to set up and maintain them. The operation of a scatternet requires some Bluetooth units to be inter-piconet units (gateways), which need to time-division multiplex their presence among their piconets. This requires a scatternet-scheduling algorithm that can schedule the presence of these units in an efficient manner. In this paper, we propose a distributed scatternet-scheduling scheme that is implemented using the HOLD mode of Bluetooth and adapts to non-uniform and changing traffic. Another attribute of the scheme is that it results in fair allocation of bandwidth to each Bluetooth unit. This scheme provides an integrated solution for both intra- and inter-piconet scheduling, i.e., for polling of slaves and scheduling of gateways.     

DDBNF：一个分布式的动态蓝牙网络形成算法

提出了一个分布式的、支持节点移动性的蓝牙匹克网构造算法DDBNF,它可以有效地将随机分布在某个区域内的n个节点划分为若干个匹克网.该算法只需获得每个节点的本地拓扑信息(一跳邻居节点),基于权值大小选举主节点,允许每个普通从节点直接访问至少一个主节点,保证了每个节点对之间快速的匹克网间以及匹克网内通信.     

Bluegon: a polygon-shaped scatternet formation algorithm for Bluetooth

Bluetooth is one of the cable-replacement technologies. It uses short-range radio links to replace connecting cables. Bluetooth enables portable devices to form short-range wireless ad hoc networks. A set of Bluetooth devices sharing a common channel can form a personal area network called a piconet. Several piconets can also be interconnected to establish a scatternet. Zaruba, Basaghi and Chlamtac proposed a mechanism for forming a distributed scatternet called the Bluetree. The algorithm is based on selecting an arbitrary node serving as the Blueroot. The Blueroot initiates the construction of the Bluetree. Though the algorithm is very simple, there are some weak points. For example, being a tree limits its routing choices. There are also the problems of overloading on the Blueroot and the many master/slave bridges on any routing path. In this paper, we will improve the weaknesses of Bluetree by eliminating the bottleneck in the Blueroot and by reducing the number of bridges to half for almost any path. We call the new algorithm Bluegon since polygons (cycles) will be formed in the scatternet. Simulation results indicate the efficiencies of our algorithm. Copyright © 2006 John Wiley & Sons, Ltd.     

Performance Evaluation of Protocols for Group-Oriented Mobile Services

The emerging mobile services, including m-commerce, have received considerable interest among researchers, developers, service providers, and users. Some of these mobile services require the support for group communications among mobile users for conducting transactions. Therefore, there is a need for protocols that are designed to support transactions for group-oriented mobile services especially under brief dis-connectivity and/or intermittent connectivity. In this paper, we identify the transaction requirements of group-oriented mobile services, present three protocol schemes and several new metrics for transactions, and evaluate the performance of protocol schemes under varying conditions. Our results show that higher levels of transaction completion probabilities and lower levels of transaction delays can be achieved to support the performance requirements of diverse group-oriented mobile services. Upkar Varshney is an Associate Professor of CIS at Georgia State University, Atlanta. He has authored over 80 papers on wireless networks, mobile commerce, and other topics in major journals and international conferences. Many of his papers are among the most widely cited publications in m-commerce. He has delivered over 50 invited speeches, including several keynotes at conferences and workshops. Upkar was awarded Myron T. Greene CIS Outstanding Teaching Award in 2000 and RCB College Outstanding Teaching Award in 2002. He is also on the editorial board of IEEE Computer, International Journal on Mobile Communications, and Communications of AIS. He has also served on the program committees several international conferences. He is a member of the ACM, IEEE, and AIS.This revised version was published online in August 2005 with a corrected cover date.     

A Location Aware Mobility based Routing Protocol for the Bluetooth Scatternet

Bluetooth is a most promising technology designed for the wireless personal area networks for the cable replacement. In this paper, a location aware mobility based routing scheme for the Bluetooth scatternet is proposed that constructs the links dynamically. Our proposed routing protocol requires location information of the nodes and constructs the route between any source and destination and reduces the number of hops. Besides, the network routing problems are analyzed and role switch operations are proposed to mitigate the problems. Moreover, the roles switch and route optimization operations are also proposed to improve route performance. Rigorous simulation works are done to evaluate the performance of our protocol in terms of mobility speed and number of mobile nodes and to compare our results with similar Bluetooth routing protocols. It is observed that our protocol outperforms in terms of energy consumption and transmission packet overheads as compared to similar Bluetooth routing protocols.

蓝牙4.0无线传感网数据采集及以太网传输设计

介绍了蓝牙4.0无线传感器网络及以太网传输技术,以基于蓝牙低功耗技术的CC2540射频单片机为核心,控制多种传感器来进行数据的采集,搭建星形拓扑的蓝牙无线传感器网络,并通过以太网接口将采集到的数据传输给远程的TCP服务器。实验结果表明,本系统具有体积小、功耗低、远距离传输等优点。     

带休眠算法的无线传感器网络MAC协议

由于无线传感器网络中每个传感器节点的能量有限,所以需要有效的MAC协议来保持能量的高效利用。在MAC协议中引入休眠算法是其中一种重要的节能方式。现有的带休眠算法的无线传感器网络MAC协议已有很多种,主要分为2大类:一类是以S-MAC协议为代表的基于休眠/监听排程方案来达到节能目的的MAC协议;另一类是以WiseMAC为代表的基于低功率信道检测方案的MAC协议。对现有的主要几种有代表性的带休眠算法的无线传感器网络MAC协议进行了描述,分析了它们各自的优缺点,并进行了对比和总结。     

Personal Area Networks: Bluetooth or IEEE 802.11?

Interconnecting all our electronic devices we carry around, such as cellular phones, PDAs, and laptops, with wireless links requires a cheap, low-power radio technology that still delivers good performance. In this context, the Bluetooth wireless technology was developed to meet the requirements introduced by these personal area networks (PANs). However, today we see a widespread deployment of wireless local area network (WLAN) radios (primarily IEEE 802.11b) also in small devices, such as PDAs. This paper will compare the PAN capabilities of a Bluetooth-based system with an IEEE 802.11b-based system. In order to focus the comparison on link and networking functionality, the IEEE 802.11b radio is assumed to be operating at the same power level as the Bluetooth radio (i.e., assuming a 0 dBm radio). Results are obtained by means of simulations in which throughput and delay are measured for multihop and overlaid PANs. Estimations on power usage are also given in the simulations. The results indicate that as the number of PANs increases, the Bluetooth-based PANs basically maintain the same bandwidth per PAN, while the corresponding IEEE 802.11-based PANs suffer significantly from the increased co-channel interference. However, for cases with a few co-channel-interfering PANs (2-3 PANs hosting about 10-15 nodes), the IEEE 802.11b-based PANs offer a higher bandwidth per user than the corresponding Bluetooth PANs, which corresponds to the difference in link bandwidth between the two systems. At high interference levels, the Bluetooth PAN offers a higher capacity than the IEEE 802.11 PAN. The latter also shows unfairness among TCP connections in the PAN at high loads. The energy efficiency, defined as successfully transmitted bits per energy unit, decreases sharply for IEEE 802.11 with increased number of PANs, while Bluetooth maintains a constant level. Packet delays are also shown to be more stable for the Bluetooth PAN than for the IEEE 802.11 PAN as the number of PANs increases.     

Analysis of TCP Performance over Mobile Ad Hoc Networks

Mobile ad hoc networks have attracted attention lately as a means of providing continuous network connectivity to mobile computing devices regardless of physical location. Recent research has focused primarily on the routing protocols needed in such an environment. In this paper, we investigate the effects that link breakage due to mobility has on TCP performance. Through simulation, we show that TCP throughput drops significantly when nodes move, due to TCP's inability to recognize the difference between link failure and congestion. We also analyze specific examples, such as a situation where throughput is zero for a particular connection. We introduce a new metric, expected throughput, for the comparison of throughput in multi-hop networks, and then use this metric to show how the use of explicit link failure notification (ELFN) techniques can significantly improve TCP performance.