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  1. 1. ISSN: 2278 – 1323 International Journal of Advanced Research in Computer Engineering & Technology Volume 1, Issue 5, July 2012 A SURVEY ON AD-HOC IN WIRELESS SENSOR NETWORKS KARTHIKA.M Research scholar, Department of Computer Science, NGM College, Pollachi, India. DR.R.MANICKA CHEZIAN Assistant Professor, Department of Computer Science, NGM College, Pollachi, India.Abstract - This paper says the performance of wireless places, in congested areas easily. Quite a lot ofad hoc network. A wireless network has several types in protocols can be anticipated to work with evenit. For more expedient usage in the wireless trait ad hoc difficult challenges of ad hoc network. Minimalnetwork is introduced. Ad-hoc network is a collection of configuration and speedy deployment make Ad hocmobile wireless nodes forming a network without any networks suitable for emergency situations likecentralized administration. Ad-hoc network consist of natural disasters or military conflicts. In an ad hocself organizing feature with low bandwidth. An ad hoc network forwarding the packets mobilenetwork doesnt rely on preexisting feature. Minimal communication is used.. Wireless Ad hoc networksconfiguration and speedy deployment make ad hoc can be classified by their application: Wireless Meshnetworks suitable for emergency situations like natural Networks (WMN), Mobile Ad-Hoc Networksdisasters or military conflicts. The dynamic and (MANET), and Wireless Sensor Networks (WSN).adaptive characteristic made the routing protocols The importance of sensor networks is highlighted byenables ad-hoc networks to be formed quickly. This their multiple usages. Wireless networks are usedpaper also presents an overview of issues related to according to theMedium Access Control (MAC), and transport in on-demand basis.wireless ad hoc networks routing techniques proposed II. TYPES OF WIRELESS NETWORKSto improve the performance of protocols. A. WIRELESS MESH NETWORKSKey Terms: Wireless network, Ad-Hoc network, A WMN is dynamically self-organized andWireless Mesh Networks, Wireless Sensor Networks. Self-configured. The gateway/bridge functionalities in mesh routers enable the integration of WMNs with I. INTRODUCTION various existing wireless networks. . Wireless networks are getting more popular B. MANETbecause of its effortlessness. Sensory data comesfrom multiple sensors of different modalities in The term MANET referred as (Mobile Addistributed locations. Wireless networks are being hoc Network). MANET are connected by wirelessmore and more used in the communication among links, it is a self-configuring router. The routers candevices of the most varied types and sizes. The change their location and organize itself randomly.wireless Ad hoc network consists of two operating The main issue inmodes: Infrastructure mode, Ad hoc mode. MANET is dynamically changing topology inInfrastructure mode is used to connect computers network. Proactive protocols are also used forwith wireless network adapters. Ad hoc mode is used convenient connect wireless clients directly together, withoutthe need for a wireless router or access point.Wireless networks can be arranged even in desert 270 All Rights Reserved © 2012 IJARCET
  2. 2. ISSN: 2278 – 1323 International Journal of Advanced Research in Computer Engineering & Technology Volume 1, Issue 5, July 2012C. WIRELES SENSOR NETWORKS must waits for the pre-defined interval of time. Slotted-ALOHA doubled the efficiency of ALOHA; In most wireless Ad hoc networks, the nodes however, it introduced the necessity ofcompete for way in to shared wireless medium, often synchronization. To minimize the number of collisionresulting interference. Using cooperative wireless another access scheme called CSMA was introduced,communications improves immunity to interference which carries sensing before transmitting the data toby having the destination node combine self- be sent. The CSMA senses the medium when sendinginterference and other- node interference to improve the current data. If the medium is busy, the carrier isdecoding of the desired signal. Multiple nodes and sensed, and the station postpones its medium accesslinks are used for an ad-hoc network. Links can be to avoid collision. The medium transmits the dataconnected or disconnected at any time; a functioning frame only if the medium is idle. After sensing thenetwork must be able to cope with this dynamic medium, depending on the scheme deployed torestructuring, preferably in a way that is timely, attempt a transmission after sensing the medium busyefficient, reliable, robust and scalable. Wireless CSMA can act as non-persistent or p-persistent.networking has witnessed an explosion of interest When the mediumfrom consumers in recent years for its applications in gets idle, the p-persistent CSMA the station transmitsmobile and personal communications. Since the with a probability p and a random period of time wasnetwork interface is a significant consumer of power, set to another medium access which is non-persistent.considerable research has been devoted to low-power The most famous access scheme for wired networksdesign of the entire network protocol stack of is a variation of CSMA persistent that detectswireless networks in an effort to enhance energy collisions. This scheme is employed by Ethernet andefficiency. In Ad hoc networks, each node may is called Carrier Sense Multiple Access withcommunicate directly to each other. Nodes that are Collision Detection. Here, the collision is notnot directly connected communicate by forwarding possible if there is a free space. This occurrence istheir traffic through intermediate nodes. referred as Hidden Terminal Problem. To represent the own transmission range each station is centeredC. MEDIUM ACCESS CONTROL (MAC) with dotted circle. Bluetooth and IEEE 802.11 are thePROTOCOLS technologies which are used mainly for implementing in wireless ad hoc networks. The station A is The important issue for an Ad hoc network transmitting to B. As station C cannot sense theis the design of a suitable Medium Access Control ongoing transmission, it may also transmit to B,(MAC) protocol. The low energy consumption, resulting in a collision at B.scalability, requirements such as quality of service(Qos), are efficiently provided by the MAC protocol.Contention-free and contention based are theclassifications of protocols for wireless networks[1].Without contending the medium, the contentionfree schemes pre-define assignments to allow stationsto transmit. In general the contention-freemechanisms are employed to provide bounded endto-end delay and minimum bandwidth, privilegingdelay sensitive applications. MAC mechanism is used Fig.1 the Hidden Terminalin Bluetooth personal area networks to employ a Problemmaster-slave. On the other hand, contention-basedschemes are more suitable for periodic data transfer CSMA carries sensing techniques but theon mobile networks due to the arbitrary and MACA(Multiple Access With Collision Avoidance)impermanent nature of the topologies. Wi-Fi local protocol does not carries sensing instead it knowsarea networks in their Ad hoc mode employ carrier sense is not possible before transmitting, socontention-based MAC protocols. For medium that the collision is may be reduced but notaccess, ALOHA and Slotted-ALOHA are the two completely eliminated. An RTS (Request-To-Send)contention-based schemes. When ALOHA has its request is sent containing the length of theframe to send station accesses the medium as soon transmission. After receiving the RTS, the destinationas possible. Collision will occur if two or more data part will send a CTS (Clear-To-Send) packet to thesent to a station at the same. But in Slotted-ALOHA sender. According to the time announced in CTS, theaccess scheme to decrease the collision probability, range of destination will defer. The length of the databefore beginning to start transmission the station frame is also mentioned. When the data is long or 271 All Rights Reserved © 2012 IJARCET
  3. 3. ISSN: 2278 – 1323 International Journal of Advanced Research in Computer Engineering & Technology Volume 1, Issue 5, July 2012have some errors the sending and receiving range of products are compliant with specification. Thethose data will defer, postponed. The station performs Bluetooth architecture consists of a basic unit calledthe collision action even after sending the RTS piconet and of scatternets. A piconet is an ad hoctransmission, the CTS is not received. A binary network formed by a master and slaves devices. Theexponential bakeoff is performed by the station to device can be a master or a slave, but not both at theresolve collision. MACAW (MACA for Wireless same time. The master is the device that establishesLANs), which adds the acknowledge (ACK) for data the piconet and the slaves are the other devices thatframes, it accelerates the loss frame recovery, belong to the piconet. The master informs the slavesinitiated only in transport level. In Figure 2, station C the logical addresses to be used, when the slaves candoes not transmit to D even if its transmission will transmit and for how long and what Frequencies mustnot interfere at destination A. All station does not be used in transmission. Communication is alwayssend frames within the range of communicating node. between a master and one or more slaves (point-to-So, the transmission uses FAMA (Floor Acquisition point or point-to-multipoint). There is no directMultiple Access) protocol sensing used with CTS communication between slaves. A piconet ismechanism. composed of a master and up to seven active slaves. Moreover, there may be up to 255 inactive devices in the network, in a low-power state. The maximum number of active devices could limit the applicability of Bluetooth, but a Bluetooth network can be extended by the interconnection of piconets. In this case, the network is called a scatternet and the piconets are interconnected by bridge nodes. The bridge between the piconets can have the role of slave in all piconets to which they belong or of master in one piconet and slave on the others. A bridge cannot be master in more than one piconet, because the master is the unit that establishes the Fig.2 the Exposed Terminal frequencies to be used in communication. Bluetooth Problem uses a Time Division Duplexing (TDD) scheme, withIn Figure 1, depending on the propagation delays, a a 625 μs slot time. The master begins its transmissionCTS from B to A may have already been received at in even slots and slaves transmit in odd slots. FramesA, but not at C. When A starts sending its data frame, can be one, three or five slots long, depending on theC has not yet received the CTS, it will frame type. M Frames are transmitted over linkssimultaneously send a RTS to B. FAMA is able to called logical channels between the master and one orsolve these problems by sending the intervals called more slaves. There are two kinds of links: ACLinter-frame spaces which increases the propagation (Asynchronous Connectionless) and SCOand process the delay of network within the station. (Synchronous Connection-Oriented). The ACL is aThere is enough time to for transmission within this point-to-multipoint link between the master and allamount of time gap. The CSMA/CA (CSMA with active slaves of the piconet. There is only one ACLCollision Avoidance) combines characteristics of link per piconet.CSMA, MACA/MACAW, and FAMA. CSMA/CAsenses the medium before transmissions, deploys V. SIMULATION OF WIRELESS AD-HOCRTS/CTS, acknowledges data frames, and uses inter- NETWORKSframe spaces to compensate propagation delays. Inthat Single Channel Protocol setup reservation for One key problem to Wireless Ad Hoctransmissions and subsequently transmit their data. networks is foreseeing the variety of possibleMultiple Channel Protocol uses more than one situations that can occur. As a result, Modeling andchannel to coordinate session among transmitter and Simulation using extensive parameter sweeping andreceiver are also referred for more convenience. what-if analysis becomes an extremely important paradigm for use in ad hoc networks. Traditional M&S tools include NS2,(and recently NS3), OPNETIV. BLUETOOTH Modeler, and Net Sim. However, these tools focus Bluetooth is a wireless technology that is primarily on the simulation of the entire protocolbeing used to deploy personal area networks and stack of the system. Although that can be importantadopted as IEEE 802.15.1 standard. Most Bluetooth in the proof-of-concept implementations of systems, the need for a more advanced simulation 272 All Rights Reserved © 2012 IJARCET
  4. 4. ISSN: 2278 – 1323 International Journal of Advanced Research in Computer Engineering & Technology Volume 1, Issue 5, July 2012methodology is always there. Agent-based modelingand simulation offers such a paradigm. Not to be [3] Z. J. Haas and J. Deng, “Dual busy tone multipleconfused with multi-agent systems and intelligent access (DBTMA)-A multiple access control schemeagents, agent-based modeling originated from social for ad hoc networks,” IEEE Transactions onsciences, where the goal was to evaluate and view Communications,large-scale systems with numerous interacting vol. 50, no. 6, pp. 975–985, June 2002."AGENT" or components in a wide variety ofrandom situations to observe global phenomena. [4] R. O. Baldwin, N. J. D. IV, and S. F. Midkiff, “AUnlike traditional AI systems with intelligent agents, real-time medium access control protocol for ad hocagent-based modeling is similar to the real world. wireless local area networks,” ACM SIGMOBILEAgent-based models are thus effective in modeling Mobile Computing and Communications Review, and nature-inspired systems. In these 3, no. 2, pp. 20–27, Apr., the basic interactions of the components thesystem, also called Complex Adaptive System, aresimple but result in advanced global phenomena such [6] S. Kumar, V. S. Raghavan, and J. Deng,as emergence. “Medium access control protocols for ad hoc wireless networks: A survey,” Ad Hoc Networks, vol. 4, no. 3,VI. CONCLUSION AND FUTURE SCOPE pp. 326–358, 2006. [7] I. A. Akyildiz and X. Wang, “A survey on This Chapter has discussed WSN issues and wireless mesh networks,” IEEE Communicationsexample solutions for the MAC layer, routing, Magazine, vol. 43, no. 9, pp. S23–S30, Sept. 2005localization. These solutions are deferent from pastnetworking solutions was stressed. The future work [8] G. Pei, M. Gerla, and X. Hong, LANMAR:of wireless networks become an integral component Landmark routing for large scale wireless ad hocof the modern communication infrastructure, energy networks with group mobility. In Proceedings of theefficiency will be an important design consideration ACM Symposium on Mobile Ad Hoc Networkingdue to the limited battery life of mobile terminals. and Computing (MOBIHOC), pages 11-18, 2000. [9] K. Xu, M. Gerla, L. Qi, and Y. Shu, “EnhancingVII. REFERENCES TCP fairness in ad hoc wireless networks using neighborhood red,” in Proc. of ACM MOBICOM,[1] S. Kumar, V. S. Raghavan, and J. Deng, San Diego, CA, USA, Sep. 2003, pp. 16–28.“Medium access control protocols forad hoc wireless networks: A survey,” Ad Hoc [10] C. L. Fullmer and J. J. Garcia-Luna-Aceves,Networks, vol. 4, no. 3, pp. 326–358, “Floor acquisition multiple accessMay 2006. (FAMA) for packet-radio networks,” in ACM SIGCOMM, pp. 262–273, Aug. 1995.[2] Ian F. Akyildiz, Xudong Wang, Welin WangComputer Network, 2005 273 All Rights Reserved © 2012 IJARCET