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2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Bali  ...
2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Bali  ...
2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Balito...
2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Balith...
2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Baliin...
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Location Based Computation Sharing
Framework for Mobile Devices

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  1. 1. 2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Bali Location Based Computation Sharing Framework for Mobile Devices Samiul. Islam, Boraq. Ammourah, and Mohamad. Mahmoud today’s mobile phones and smart phones and we have Abstract— Third generation and fourth generation mobile proposed our process sharing framework for mobile devices,devices are providing various online services and applications to based on this technology.facilitate users with their rich web interfaces. Limited computing In section II and III of this paper, we have provided anpower and shorter battery life of mobile devices caused computation overview of cellular network and working principle ofintensive application components to migrate to the externalcomputing resources. By elastic resource provisioning and the ability Bluetooth. We have described our proposed framework into support large scale service deployment, mobile cloud computing section IV. Section VI contains some part of evaluation of ourintroduced an attractive platform for offloading the computational framework and we concluded with section VII.processes among mobile devices. In this paper we proposed alocation based computation sharing framework for mobile devices in II. OVERVIEW OF CELLULAR NETWORKwhich mobile devices locating in the same cell can share theirprocessing power. We introduced a certification technique by which Modern mobile phone networks use cells (Fig. 1) becauseall mobile devices within 10 meters ranges can share their processing radio frequencies are a limited, shared resource. Cell-sites andpower using Bluetooth technique without traditional 2 step handsets change frequency under computer control and useverification process. low power transmitters so that a limited number of radio frequencies can be simultaneously used by many callers with Keywords— Bluetooth Connectivity, Computational Process less interference. A cellular radio system provides a wirelessSharing, Mobile Computing, Wireless Ad-hoc Network. connection to the public telephone network for any user location within the radio range of the system. The term mobile I. INTRODUCTION has traditionally been used to classify a radio terminal that canT ECHNOLOGICAL advance in radio communication introduced to us with wireless ad-hoc networks. These areself-organizing networks that are formed from wireless be moved during communication. Cellular systems accommodate a large number of mobile units over a large area within a limited frequency spectrum [3].devices communicating with each other without the need ofany infrastructure. In these networks, each device (or node)works as a terminal and a router at the same time. The nodesare allowed to join or leave the network at any time. Nodesmay also move from one geographical position to another atany time. Different wireless radio technologies were proposedto enable wireless ad hoc networks; one of them is Bluetooth[1]. The technology is promising in many ways. First,Bluetooth devices are efficient with respect to powerconsumption. Second, Bluetooth devices use a communicationmechanism that is noise-resistant and robust againstinterference with neighboring Bluetooth devices. Third, thecost of Bluetooth radio devices is relatively low. Bluetoothalso offers ad-hoc networking capabilities [2]. These Fig.1 Mobile cell architecture.advantages of Bluetooth led its deployment in a wide range of A cellular network is used by the mobile phone operator to Samiul. Islam is with the Department of Computer Science, College of achieve both coverage and capacity for their subscribers.Computer Science and Information System in Najran University, Najran, Large geographic areas are split into smaller cells to avoidSaudi Arabia (phone: +966 75428610 ; Mobile: +966 501343118; e-mail: line-of-sight signal loss and to support a large number Boraq. Ammourah is with the Department of Computer Science, College active phones in that area. All of the cell sites are connectedof Computer Science and Information System in Najran University, Najran, to telephone exchanges (or switches), which in turn connect toSaudi Arabia (phone: +966 75428615 ; Mobile: +966569596556; e-mail: the public telephone network. Each cell contains at least Mohamad. Mahmoud is with the MIS department in Salman bin AbdulazizUniversity, Hot at Bani, Tamim, Saudi Arabia. (Phone: +966 543170968; e-mail: ). 156
  2. 2. 2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Bali Legend: M- Master device, S- Slave device M S S M S S S S Piconet- A Piconet- B Fig. 3 Scatternet in a mobile cell Fig. 2 Communication of BTS and mobile phones i.e. a node can be a master in one piconet and a slave inbase transceiver station (BTS), under which all cell phones of another. This permits the connection of several piconets as thethat cell are registered. The base transceiver station, or BTS, nodes functioning in master/slave mode act gateways betweencontains the equipment for transmitting and receiving radio piconets. In the Bluetooth concept the network topologysignals (transceivers), antennas, and equipment for encrypting resulting by the connection of piconets is called a scatternetand decrypting communications with the base station (Fig. 3). A node can be active in only one piconet at time, andcontroller (BSC). Fig. 2 shows BTS functionality in a simple to operate as a member of another piconet, a node must switchmanner. to the hopping frequency sequence of the other piconet [5]. The base station subsystem (BSS) is the section of a The Bluetooth Core Specification provides for thetraditional cellular telephone network which is responsible for connection of two or more piconets to form a scatternet, inhandling traffic and signaling between a mobile phone and which certain devices simultaneously play the master role inthe network switching subsystem. The BSS carries one piconet and the slave role in another. A master Bluetoothout transcoding of speech channels, allocation of radio device can communicate with a maximum of seven devices inchannels to mobile phones, paging, transmission a piconet (an ad-hoc computer network using Bluetoothand reception over the air interface and many other tasks technology), though not all devices reach this maximum. Therelated to the radio network. Typically a BTS will have several devices can switch roles, by agreement, and the slave cantransceivers (TRXs) which allow it to serve several different become the master.frequencies and different sectors of the cell (in the case ofsectorized base stations). A BTS is controlled by a parent base A. Operationsstation controller via the base station control function (BCF). Bluetooth uses a radio technology called frequency-hoppingThe BCF is implemented as a discrete unit or even spread spectrum, which chops up the data being sent andincorporated in a TRX in compact base stations. The BCF transmits chunks of it on up to 79 bands (1 MHz each;provides an operations and maintenance (O&M) connection to centered from 2402 to 2480 MHz) in the range 2,400–the network management system (NMS), and manages 2,483.5 MHz (allowing for guard bands). This range is in theoperational states of each TRX, as well as software handling globally unlicensed Industrial, Scientific and Medical (ISM)and alarm collection. The basic structure and functions of the 2.4 GHz short-range radio frequency band. It usually performsBTS remains the same regardless of the wireless technologies 800 hops per second, with AFH enabled [6].[4]. Bluetooth operation relies on packet-based protocol with a master-slave structure. One master may communicate with III. BLUETOOTH: WORKING PRINCIPLE up to 7 slaves in a piconet; all devices share the masters clock. Bluetooth is a short-range radio technology that enables Packet exchange is based on the basic clock, defined by thewireless connectivity between mobile devices. When two master, which ticks at 312.5 µs intervals. Two clock ticksBluetooth devices come into each other’s communication make up a slot of 625 µs; two slots make up a slot pair of 1250range, one of them assumes the role of master of the µs. In the simple case of single-slot packets the mastercommunication and the other becomes the slave. This simple transmits in even slots and receives in odd slots; the slave,“one hop” network is called a piconet, and may include up to conversely, receives in even slots and transmits in odd active slaves connected to one master. As a matter of Packets may be 1, 3 or 5 slots long but in all cases the master-fact, there is no limit on the maximum number of slaves transmit will begin in even slots and the slave-transmit in oddconnected to one master but only seven of them can be active slots. The master chooses which slave device to address;at time, others have to be in so called parked state. The typically, it switches rapidly from one device to another inspecification also allows multiple roles for the same device, a round-robin fashion. Since it is the master that chooses which slave to address, whereas a slave is (in theory) supposed 157
  3. 3. 2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Balito listen in each receive slot, being a master is a lighter burden state, they do not have addresses, but only listen enough tothan being a slave. keep their synchronization with the master and check for Bluetooth devices can be in 3 different power classes [7], broadcast messages.[8]: C. Security MethodClass 3: The lowest power, the max. range of this is 10mClass 2: Max range is about 50m (150ft) Authentication ensures the identity of Bluetooth devices. ItClass 1: Max range is about 100m (300ft) authenticates the device at the other end of the link.These ranges (Table-I) can be affected by environmental Authentication is accomplished by using a stored link key orconditions i.e. furniture, walls, people so ranges can easily be by pairing (entering a PIN). Pairing is a procedure thatreduced. Bluetooth is not a line of sight connection so it can be authenticates two devices based on a common passkey,used through walls and floors. thereby creating a trusted relationship between those devices. An arbitrary but identical passkey must be entered on both TABLE I devices. As long as both devices are paired, the pairing BLUETOOTH CLASSES procedure is not required when connecting those devices again Maximum permitted power Range (the existing link key is used for authentication). Devices Class without any input method, like headsets, have fixed passkeys. (mW) (dBm) (m) Authorization is a process of deciding if a device is allowed Class 1 100 20 ~100 to have access to a specific service. User interaction may be Class 2 2.5 4 ~10 required unless the remote device has been marked as "trusted." Usually the user can set authorization on/off to Class 3 1 0 ~5 every remote device separately. Authorization always requiresThe effective range varies due to propagation conditions, authentication.material coverage, production sample variations, antenna Encryption protects communication against eavesdropping.configurations and battery conditions. In most cases the For example, it ensures that nobody can listen to what a laptopeffective range of class 2 devices is extended if they connect transmits to a phone. The length of the encryption key can beto a class 1 transceiver, compared to a pure class 2 network. between 8 and 128 bits.This is accomplished by the higher sensitivity andtransmission power of Class 1 devices. IV. PROPOSED FRAMEWORK B. Connection Protocols All mobile devices under a BTS can be grouped in a Bluetooth connections are established via the following multiple piconets, where the number of piconets depends ontechniques [9], [10]: the cell size of that specific BTS depending on geographical Standby: Devices not connected in a piconet are in standby position. Each piconet can contain maximum n number ofmode. In this mode, they listen for messages every 1.28 s over mobile devices at any given time, where 0≤ n. When an32 hop frequencies (fewer in Japan, Spain, and France). application initiates in any node of a piconet of our proposed Page/inquiry: If a device wishes to make a connection with framework, it has been marked as an active node and acquire aanother device, it sends out a page message if the address is certificate from local BTS with a time stamp for that node.known, or an inquiry followed by a page message if it is When an active node has been selected, it discovers the idleunknown. The master unit sends out 16 identical page nodes asynchronously within its piconet and use the certificatemessages on 16 hop frequencies to the slave unit. If there is no to create a private channel with the idle nodes to share theirresponse, the master retransmits on the other 16 hop processing powers. If the time stamp of an active nodefrequencies. The inquiry method requires an extra response exceeds the duration more than 300 seconds, and/or thefrom the slave unit, since the address is unknown to the master number of idle nodes drop below a level m, where 1≤ m≤7,unit. the active node share its processes with the other available idle Active: Data transmission occurs. nodes in different piconets through BTS. The proposed Hold: When either the master or slave wishes, a hold mode framework is composed of several algorithms implemented inis established or no data is transmitted in order to conserve middle layer of BTS and in the application layer of cellpower. Otherwise, there is a constant data exchange. A typical phones. Those can be categorized as mentioned in later subreason for going into hold mode is the connection of several sections.piconets. A. Certificates: Sniff: The sniff mode, applicable only to slave units, is for Subscriber, MS (Mobile Station) or mobile phone connectspower conservation, though not at as reduced a level as hold. to mobile network through BTS. When a mobile phoneDuring this mode, the slave does not take an active role in the switches on, it registers with the corresponding BTS of its cell.piconet, but listens at a reduced level. This is usually a In our proposed framework, during the registration process ofprogrammable setting. mobile devices, it will acquire a certificate from the Park: Park mode is a more reduced level of activity than the corresponding BTS, containing subscriber’s information andhold mode. The slave is synchronized to the piconet, thus not service provider’s information. This certificate authenticatedrequiring full reactivation, but is not part of the traffic. In this 158
  4. 4. 2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Balithe device with a device generated 64 bit encrypted security finding other devices listening to the same frequency hop atkey. An active node shares this key in the idle node discovery the same time. The inquirer keeps alternating in a range ofprocess within the piconets. During the link establishment frequencies - 32 out of the 79 available hops known to all theprocess and data exchange process between these two types of devices. On the opposite side of the connection, a node thatnodes, the security key will automatically authorize an active wants to be discovered has to switch to the query scan statenode to send and retrieve its data from an idle node without and keeps listening to ID packets generated from the inquirers.prompting the user. The scanner switches between the frequencies hops at a slower rate than the inquirer’s in order to increase the chance of B. Discover idle nodes with timestamp: finding each other in the same hop. When the scanner receives We require time synchronization between mobile nodes. one of those ID packets, it replies to it with a special packetWe assume clock ticking speeds of different nodes to be called the FHS [11], [12] packet. An FHS packet contains itscomparable. It means that when a idle node B i receives a clock address and its clock value. The clock value is used forvalue from an active node A i , node B i can synchronize with synchronization purposes to make the link establishmentnode A i , using A i ’s clock value. There is no globally common procedure faster. In the paging procedures, the active nodeclock for the mobile network, say MN. Assume that MN has switches to the page state and the idle must switch to the pageM channels available for its operations. Let this channel set be scan state. Using the information obtained from the FHSCglobal = {C1, C2 , ... , CM}. packet, the active node adds an offset value to its clock to have Each node in MN is assigned a unique identifier (Node ID) the same clock value of the idle node so they are both becomein the range 1 to N. Each node knows its unique Node ID, but synchronized to each other. After that, the active nodedoes not know how many other nodes there are and what their attempts to contact the idle node by broadcasting again aIDs are. Nodes are equipped with one transceiver (Transmitter number of ID packets. If the idle node listens to one of these& Receiver) capable of either receiving or transmitting at any ID packets, it replies with another ID packet and go to the idlegiven time. Nodes know about the global channel set Cglobal response state. When this ID packet is received by the activeand the value of N. Also each node finds its set of usable node, it changes its state to the active response state. Then, thechannels (available channel set) by a periodic scanning active node sends an FHS packet.mechanism. We assume nodes can detect collisions. An activenode transmits and receives alternatively on each channel of V. RELATED WORKits available channel set. During the transmit period it sends a Salonidis et. al. presents a distributed topology constructionquery referred to as Active Node Query (ANQ) with node ID, scheme in Bluetooth networks [13]. The basic assumptionclock value of the node, available channel set and remaining behind the scheme is that all nodes are within transmissiontime in ANQ. Every ANQ has limited time validity, Q t . range of each other. The nodes conduct a leader electionDuring the receiving period, inquiring node listens on the algorithm. The winner knows the identity of all nodes and usessame channel that it transmitted previously, for duration of Q t . this information to design the desired topology. ExistingIf a valid reply (Query Reply) is received, the queering node service discovery protocols such as Universal Plug and Playsends an Acknowledgment (Ack) message, during the current (UPnP) [14], Service Location Protocol (SLP) [15] andreceiving period or during the next receiving period, on the Salutation focused on auto configuration issues allowingsame channel that it received the reply. Upon receiving a devices to automatically join the network and learn about itsQuery Reply message, inquiring node discovers the sender of capabilities. However such approaches were designed forthe Query Reply. resource rich networks and are not suitable for resource C. Sharing and synchronization of process: constrained systems. Energy efficient service discovery has Bluetooth operates in the range of frequencies 2.4000 GHz been done using power efficient wake-up schedulingto 2.4835 GHz. It divides the medium to 79 channels each of 1 protocols, such as [16][17][18]. Bhagwat et al. presents aMHz. The rest of the available frequencies are considered as source routing mechanism for Bluetooth networks [19]. Das etlower and upper band edges, in order to comply with the radio al. [20] and Johanson et al. [21] present distributed schedulingregulations of different countries. To establish a link between policies for Bluetooth networks. Existing middlewarean active and idle node, the communicating nodes must solutions for wireless sensor networks usually have plug-inperform two operations; the first is the query; in which one system [22] for service discovery protocols or use their ownnode gets the address of (or discovers) another node. The mechanisms [23]. TeenyLime [23] is a data-sharingsecond is the paging, in which a link is constructed. The middleware designed for mobile sensors. It uses an operationalspecifications of Bluetooth state that for one node to discover setting where sensors are fixed and relatively powerful mobileothers, it must switch to the query state, and then, keeps sinks are used to collect data from sensors.broadcasting small special packets (of 68 bits size), called theID packets. The contents of these packets are common to all VI. EVALUATIONBluetooth devices, and although called ID packets, they do not Evaluation of certificate is our future work. The timecontain the identity of their senders. The inquirer’s ID packets duration of idle node discovery procedure has been evaluatedmust be broadcast in different frequency hops in hope of 159
  5. 5. 2nd International Conference on Emerging Trends in Computer and Image Processing (ICETCIP2012) June 30-July 1, 2012 Baliin a simulated environment. Discovery of each idle node is [5] Gergely V. Záruba, Stefano Basagni and Imrich Chlamtac: Bluetrees – Scatternet Formation to Enable Bluetooth-Based Ad Hoc Networks,marked as T 1 and presented by (1). IEEE, 2001, ISBN 0-7803-7097-1. [6] T 1 =2 Q t (M+1)M (1) interface-modulation.php. [7] Albert Huang and Larry Rudolph, Bluetooth for Programmers, 2005. The simulation was done by using the R [20] statistical [8] assuming that a network with 3 channels (M = 3). Classes.html.Also consider two nodes (A and B) in the network with [9] K. Sand, Bluetooth, Tik-111.550 Seminar on Multimedia,available channel sets A = {3}, B = {1,2,3}. The T1 duration Telecommunications Software and Multimedia Laboratory, Helsinki University of Technology, Finland, March shown in the fig. 4. [10] J. Haarsten, Bluetooth —the universal radio interface for adhoc wireless 2Qt connectivity, Ericsson Review 3 (4) (1988) 1 – 5. available at _ 98/art1/art1.html. [11] T. Salonidis, P. Bhagwat, L. Tassiulas, R. LaMaire, Distributed Topology Construction of Bluetooth Personal Area Networks, Proceedings. IEEE, Volume: 3, 2001, pp. 1577-1586, IEEE INFOCOM 2001. [12] A. El-Hoiydi, Interference Between Bluetooth Networks – Upper Bound 2Qt (M+1) on the Packet Error Rate, IEEE Communications Letters, Vol. 5, No. 6, pp. 245-247, June 2001. [13] T. Salonidis, P. Bhagwat, L. Tassiulas, and R. Lamaire. Distributed T1 =2 Qt (M+1)M topology construction of Bluetooth personal area networks. In Fig. 4 T 1 duration for 3 channels Proceedings of INFOCOM’2001, 2001. [14] Universal plug and play. http://www. [15] E. Guttman. Service location protocol: Automatic discovery of IP We have evaluated our sharing and synchronization network services. IEEE Internet Computing, 3(4):71-80, 1999.algorithm in a simulated state with maximum 30 nodes. The [16] W. Ye, J. Heidemann, and D. Estrin. Medium access control with coordinated adaptive sleeping for wireless sensor networks. IEEE/ACMresult shows (fig. 5) the processing performance with time. Trans. Netw. 12(3):493-506, 2004.We assumed that every node has its own unique ID and a [17] J. Polastre, J. Hill, and D. Culler. Versatile low power media access fordirect connection method has been used instead of certificate wireless sensor networks. In SenSys04: 2nd international conference ontechnique to evaluate their performances. Embedded networked sensor systems, pages 95-107, New York, 2004. [18] W. Ye, F. Silva, and J. Heidemann. Ultra-low duty cycle mac with scheduled channel polling. In SenSys06: Proceedings of the 4th international conference on Embedded networked sensor systems, pages 321-334, New York, NY, USA, 2006. ACM Press. 30 [19] P. Bhagwat and R. Seigal. A routing vector method (RVM) for routing 20 in Bluetooth scatternets. In IEEE International Workshop on Mobile 10 Multimedia Communications (MoMuC’99), San Diego, CA, Nov 1999. [20] A. Das, A. Ghose, A. Razdan, H. Saran, and R. Shorey. Enhancing performance of asynchronous data traffic over the Bluetooth wireless ad- hoc network. INFOCOM’2001, Anchorage, AK, April 2001. [21] N. Johansson, Korner, and L. Tassiulas. A distributed scheduling algorithm for a Bluetooth scatternet. ITC’2001, Salvador, Brazil, Dec. Fig. 5 Shared process performance measure 2001. [22] W. Heinzelman, A. Murphy, H. Carvalho, and M. Perillo. Middleware to support sensor network applications, 2004. VII. CONCLUSION [23] C. Curino, M. Giani, M. Giorgetta, and A. Giusti. Tiny lime: Bridging We have evaluated our result partially for idle node mobile and sensor networks through middleware. In Tiny Lime: Bridging Mobile and Sensor Networks through Middleware. March 8-discovery and process sharing. Future work involved 12, 2005.implementation and evaluation of certification algorithm,Synchronization with BTS to share processing with the idlenode of different piconets within the same cell.. Few criticalconcerns also need to be considered in future work, e.g. whentwo active nodes try to share an idle node in concurrent time.Fault tolerance mechanism need to be implemented as anyshared node can be switched of or change location withoutprior notice. REFERENCES[1] Bluetooth Core Specifications v2.1 + EDR,[2] Ahmed Jedda, The Device Discovery in Bluetooth Scatternet Formation Algorithms, Ottawa-Carleton Institute for Computer Science, University Of Ottawa, Canada, 2009.[3] Kamil Sh. Zigangirov, Theory of Code Division Multiple Access Communication, ISBN 0-471-45712-4, Institute of Electrical and Electronics Engineers, 2004.[4] 160