BlueScouts: A Scatternet Formation BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Protocol Based on Mobile Agents Sergio González-Valenzuela 1 Son T. Vuong 2 Victor C. M. Leung 1 1 Department of Electrical and Computer Engineering 2 Department of Computer Science The University of British Columbia Vancouver, Canada 4 th Workshop on Applications and Services in Wireless Networks Boston, Massachusetts, USA August 2004 IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Presentation Outline Introduction � Scatternet formation through mobile processing � BlueScouts: On-demand scatternet formation � Simulation results � Conclusions � IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Introduction What is Bluetooth? Global standard for short-range wireless communications � 10 meters @ 721 Kbps / 3 Mbps (Enhanced Data Rate - � EDR) Enables data and voice communications - WPAN � High level of hardware integration & low power � consumption Ideal for PDAs, cell phones, etc. � Economic impact: shipping currently estimated at 2 million � Bluetooth-enabled products per week worldwide IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Introduction Bluetooth Primitives Sample Bluetooth Scatternet Projector Bluetooth device discovers � Piconet 1 neighbouring devices via inquiry process Tablet Laptop Devices assume either a � PC Computer master or slave role. A master PDA2 handles up to seven slaves in PDA1 Cell active communications Phone connected in a star-shaped Fax IP Phone topology - piconet Internet Access Point Piconets may be � Printer Piconet 2 interconnected via bridges to create a scatternet IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Introduction Issues Problem definition: How do we create scatternets efficiently? � Several existing proposals: Bluestar, Bluemesh, Bluenet, � Bluetrees, TSFP, SFP, DTC, etc. Assumptions often made by existing SFPs: � • Synchronous start/operation: Devices are somehow able to initialize the protocol at the same time, and must wait for partial computations from other devices to proceed with own decisions • All BDs must be within radio range of each other • Additional BDs cannot join the scatternet at a later time IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Scatternet Formation Through Mobile Processing Our proposed solution Limitations of existing approaches attributed to the � communication models they employ We propose a novel mobile agent-based solution � Contrary to what existing schemes do, we decouple device � discovery from actual topology formation Eliminates constraints often seen in existing approaches: � Protocol runs in a fully asynchronous fashion � Absolute radio coverage among all BDs no longer a constraint � Scatternet can grow dynamically � IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Scatternet Formation Through Mobile Processing Our proposed solution (cont’d) Employed Wave as our mobile processing implementation � tool to code ‘light-weight’ mobile agents Wave ’s key features: � • An internal mechanism for automated spatial coordination of mobile agents ( Track Layer ) • An scripting-like language that enables highly compact agent code, leading to reduced bandwidth consumption • External interfacing, enabling the interpreter to utilize existing resources (e.g. Bluetooth HCI APIs) Other agent platforms can be used, but would require much � more programming to accomplish the same objective IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents BlueScouts: On-Demand Scatternet Formation Agent spreading mechanism Wave agents spread through the existing links in a controlled fashion and recursively signal back the state of the last computation’s outcome (false, done, true, abort), leading up to the further replication of the mobile process or its termination. Agent WI WI Echo Process Process termination start A 1 A 2 A 3 A 4 E 1 E 2 E 3 E 4 E 5 IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents BlueScouts: On-Demand Scatternet Formation BlueScouts in action Case 1: A BD is discovered by a master and becomes slave S S M 9 S S (nothing to do) IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents BlueScouts: On-Demand Scatternet Formation BlueScouts in action Case 2: A BD is discovered by a slave and becomes master. Agents are launched in an attempt to reconfigure the new BD’s role. S S S S M M or… M S S S M Unsuccessful reconfiguration (a scatternet is formed) Successful reconfiguration IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents BlueScouts: On-Demand Scatternet Formation BlueScouts in action Piconet 2 S Case 3: Agents conduct a S coordinated spatial depth-first S Piconet 4 search over a logical backbone M (i.e. excluding leaf nodes) in S S an attempt to reconfigure the S M new BD’s role. M S S S S Piconet 3 S M S S M S Piconet 1 Piconet 5 IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Simulation Results Simulation parameters � Periodic node arrivals � Nodes are uniformly distributed 10, 20 & 40 square meter areas � A Wave agent (204 bytes) fits in a single DM5 ACL packet � (224 Bytes) 50 simulation runs per test area � � Reasonably large scatternets – 200 nodes IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Simulation Results 16 0.35 10x10 14 10x10 0.3 12 20X20 Piconets probed 20x20 0.25 10 Delay (sec) 40X40 0.2 40x40 8 0.15 6 0.1 4 0.05 2 0 0 10 30 50 70 90 110 130 150 170 190 10 30 50 70 90 1 1 0 1 3 0 1 5 0 1 7 0 1 9 0 Scatternet size (nodes) Scatternet size (nodes) Number of piconets probed Process completion delay IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Simulation Results 8 100 7 10x10 S l a v e s p e r m a s t e r 6 20x20 5 D i a m e t e r 40x40 4 10 10x10 3 20x20 2 40x40 1 0 1 10 30 50 100 200 1 21 41 61 81 101 121 141 161 181 Scatternet size (nodes) Scatternet size(nodes) Scatternet diameter Slave/Master ratio IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Simulation Results 35 25 10x10 Bandwidth (Kilobytes) Number of piconets 30 20 20x20 25 15 40x40 20 15 10x10 10 10 20x20 5 5 40x40 0 0 1 11 21 31 41 51 61 71 81 91 1 0 3 0 5 0 7 0 9 0 110 130 150 170 190 101 111 121 131 141 151 161 171 181 191 Scatternet size (nodes) Scatternet size (nodes) Total number of piconets Consumed bandwidth IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Simulation Results Discussion � Changes to the Baseband specification are transparent to our scheme: agents employ APIs available at the nodes � Existing schemes greatly emphasize on results at the Baseband layer: incompatible performance metrics deem a direct comparison mostly impractical � Topology optimality not degraded as scatternets grow: slaves/master ratio performance is comparable or better Bandwidth consumption very low and linear � � Security issues attributed to mobile agents are less of a concern here: the interpreter lives around L3, not L7 IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Conclusions First mobile agent-based scatternet formation protocol (to � our knowledge) � Agent approach helps decouple scatternet formation from device discovery, which greatly facilitates the topology reconfiguration process � Agent approach enables fully asynchronous protocol operation and helps to eliminate constraints observed in existing schemes ‘Programmable’ approach introduces unmatched flexibility � by allowing context-aware topology formation IEEE ASWN 2004, August 10 th , 2004
BlueScouts: A Scatternet Formation Protocol Based on Mobile Agents Acknowledgements This research is supported by the National Sciences and Engineering Research Council of Canada (NSERC) through grant STPGP 257684, the Canadian Institute for Telecommunications Research (CITR) Network of Centres of Excellence, and the Advanced Systems Institute (ASI) of British Columbia. Thanks to the anonymous reviewers of our paper! Thank you! IEEE ASWN 2004, August 10 th , 2004
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