Data Gathering And Dissemination In Wireless

Data Gathering And Dissemination In WirelessA radio sensing element lucre is special kind of ad hoc nedeucerks that consists of a com positione of poor-cost, low-power, and multi-functional radio soak upr detector guests, with sensing, radio receiver communications and computation capabilities 1,2,3. These detector thickeners promulgate over a short range via a radiocommunication moderate and collaborate to accomplish a common task, kindred environmental monitoring, legions surveillance, and industrial process control 3. Wireless detector ne twainrks sacrifice exposed up for newly opportunities to observe and interact with the physical environment close to us. They enable us now to collect and gather entropy that was unwieldy or impossible before 4. Although Wireless Sensor Ne devilrks have disposed new instructions to provide info from variety of covers, irrespective of the reputation of physical environment, it is seen as a ch t start ensembleenging tas k to extract information from sensing element network. Data scattering and company ar two terms handlingd in demodulator networks to describe two categories of entropy intervention rules. Data ventilation is a process by which entropy and queries for entropy argon routed in the demodulator networks where as data throng is to put across data that has been collected by the sensor clients to the base stations. Data forum communications protocols aim to minimize the push exactlyton spending and thwart of data gathering process 5. Although there atomic number 18 differences between these two but to the highest degree altogether the literature called together as routing protocols. Un uniform traditional wireless communications networks such(prenominal) as mobile ad hoc and cellular systems, wireless sensor networks have the sideline unique characteristics and constraints 3 high density sensor guest deployment, battery or no power sensor nodes, low memory a nd processor capacity, self-configurable, unreliable sensor nodes, data redundancy, application precise and dynamic topology. Due to supra characteristics and constraints of wireless sensor networks, the extraction of data from the network is always a challenge. Therefore, it is important that the design of protocols for data gathering and dissemination takes cargon alert these challenges. The main design challenges of routing protocols for wireless sensor network are aught, Processing power and Memory. Some of the design challenges as reflected in 3, 6 are highlighted belowLarge number of sensor nodes Since some of the wireless sensor networks composed of large sensor nodes, it is precise hard-fought to have an addressing scheme like otherwise wireless networks. The traditional IP scheme is non feasible to apply for wireless sensor networks. Moreover, the sensor nodes are deployed at ergodic in hostile environment.Limited force capacity The sensor nodes are battery powe red, so they have modified pushing. This is the main challenges in designing wireless sensor networks. In class period, sensor network deployment pull outs sense only if they faeces run unattended for months and age without running short of muscularity 4.Flow of Data Al nearly all the applications of sensor network require the sensory data from multiple tooth roots to settle towards a single destination node called sink in argument to the traditional networks.Sensor node locations Most of the proposed routing protocols assumed that the sensor nodes are equipped with global positioning system (GPS), but in practice it is very difficult to manage the locations of sensor nodes. It has become more challenging as sensor networks topology changes frequently due to node failures, abject from the coverage area.Data redundancy Data collected by miscellaneous sensor nodes are typically based on common phenomenon hence the probability of data redundancy is very high. The routing protocol needs to hold data accruement techniques to decrease the number of infection.Application Specific The sensor networks are application specific. The requirement of routing protocol changes as per the specific application. It is very challenging to design routing protocols which dejection meet the requirements of all applications.Scalability The size of the network grows, so the routing protocols need to be scalable to suffer the addition of sensor nodes. All sensors may not necessarily have same capabilities of susceptibility, affect, sensing and communications. These should be taken care while designing the routing protocols.Addition to the above parameters the designing of routing protocols for wireless sensor networks as well need to look into following points 6 Node deploymentRelated workSince wireless sensor networks gain its role in various application areas, there is a growing refer in this field leading towards continual emergence of new architectural techni ques. Wireless sensor network is widely considered as one of the most important technologies of the 21st century 8. In this section we bring out and highlight how our survey differs from the similar surveys done previously in this area. We similarly highlight the scope and target group who will benefit from our work.In 2, similar survey was carried out on routing protocols for wireless networks. The information in 2 was published some five years back and many new protocols have not covered. In 3, although it has covered almost all the routing protocols for wireless sensor networks but it does not provide insight knowledge about the protocols. The survey is good for readers gratifyed in broad area. The goal of 8 is to run a comprehensive survey on routing techniques focusing on mobility issues in sensor networks and does not cover all the routing protocols in wireless sensor networks. In this survey, we bring out the comparative study among wireless sensor network routing protocol s bringing their differences and similarities. We overly bring out the advantages and disadvantages of contrary protocols to workout in different applications of wireless sensor networks. This survey would be usable for both introductory readers as well as for aspirant researchers who would like to get the comprehensive idea about the current-state-of-art regarding the techniques of data gathering and dissemination in wireless sensor networks. However, we follow 3 in classifying the routing protocols into different categories although we put some additional protocols which are not covered by 3. We overly excluded multipath-based protocol category since it falls under data-centric category. Table 1 shows the different categories of wireless sensor network routing protocols inspired by 3. The representative protocols with (*) label are our additions.Table 1 Routing Protocols for WSNsCategory of ProtocolsRepresentative ProtocolLocation-based ProtocolsMECN, SMECN,GAF, GEAR, Span, TBF, BVGF, GeRaFData-centric Protocols gyrate, enjoin dispersal, rumor Routing, COUGAR, EAD, ACQUIRE, Information-Directed Routing, Gradient-based Routing, Energy-aware routing, Information Directed Routing, Quorum-based Information dissemination, Home Agent-based Information Dissemination, *Flooding, *Gossiping.Hierarchical-based ProtocolsLEACH, PEGASIS, HEED, TEEN, APTEENMobility-based ProtocolsSEAD, TTDD, roast mobility and routing, Data MULES, Dynamic Proxy Tree-based Data Dissemination, *MDCHeterogeneity-based ProtocolsIDSQ,CADR,CHRQoS-based ProtocolsSAR, SPEED, Energy-Aware Routing.Data-Centric ProtocolsThe protocols are differentiated into two categories called data-centric and address-centric. The address-centric routing protocols find the shortest path between author and the destination with addressing scheme like IP whereas in data-centric routing protocols focus is made to search routes from multiple source nodes to a single destination node. In the sensor networks, data-centric routing is preferred where data consolidation and accruement is done by the intermediate nodes on the data coming from multiple sources before sending to the sink node. This way, it saves some energy preventing redundant data transmittances. In this section, we highlight some of the samples of data-centric routing protocols proposed for wireless sensor networks.FloodingFlooding 5 is a data dissemination method where each(prenominal) sensor node that receives a packet mobilizes it to its neighboring nodes assuming that node itself is not the destination of the packet. This process continues until the packet arrives the destination or the maximum hop counts for that packet is reached. Flooding though is a simple and diff aim to implement, but it has line of work like implosion (duplicate marrow sent to the same node) and coincide (duplicate message receive by the same node) 2. Figure 1 and 2 reproduced from 2 shows the implosion and overlap problems in flooding.Go ssipingGossiping 5 is based on flooding, but nodes that receives the packet forwards it only to a single randomly selected neighbor. It avoids implosion problem of flooding and it does not waste as much network resources as flooding. However, gossiping is not a reliable data dissemination method since the neighbor node is selected at random, some nodes may not receive that message at all. Moreover, it introduces a delay in propagation of data by dint of the nodes 2 since all the nodes which forwards or sends data need to select a node.SPINSensor Protocols for Information via Negotiation (SPIN) 9, 10 aims to improve the implosion and lapping problems of classic flooding protocol. The SPIN protocols are based on two key mechanisms namely negotiation and resource adaptation 3. It uses trine types of messages 5 ADV, REQ, and DATA. The sensor node which has collected data sends an ADV message using high-level descriptors or meta-data regarding the actual data. The actual data is tran smitted only when the REQ message is accredited from the beguileed nodes. This negotiation mechanism avoids the overlapping and implosion problems of classic flooding because the REQ message is sent from the interested node only when it does not have that data. Fig. 3, redrawn from 5 shows how these three messages are exchanged and fig. 4 inspired by 9 and reproduced from 11 shows more detail process who SPIN works.There are about four versions of SPIN protocols 6, 9, 10. They are SPIN-PP, SPIN-BC, SPIN-EC and SPIN-RL. Both SIPN-PP and SPIN-BC works under ideal condition when energy is not constraint and packet are never lost. SPIN-PP tackles the data dissemination problem by using point to point media where as SPIN-BC uses broadcast media. There other two protocols are the modified versions of SPIN-PP and SPIN-BC in aim to network which are not ideal. SPIN-EC is actually SPIN-PP with additional energy conservation capability. Under SPIN-EC, the nodes participate in data dissem ination only when it computes that it has comme il faut energy. If the node has plentiful energy, it works as same as SPIN-PP with 3-stage handshake. SPIN-RL is a version of SPIN-BC which tries to recover from the losses in the network by selectively retransmitting the messages.In SPIN topological changes are topical anaestheticized as each node needs to have information of their next immediate one-hop neighbor only. further this type of protocol cannot be used in applications where reliability is of great concern like afforest fire and intrusion detection since it does not guarantee the data delivery 2. If the nodes that are interested in data are located far way and the intermediate nodes are not interested then the ADV message will not standard which in turn will not able to get data.Directed DiffusionDirected Diffusion 12 consists of elements like interests, data, messages, gradients and reinforcements. The main objective of the protocol is to use naming scheme to reduce t he energy usage by avoiding surplus routing operations. Interest is a research or interrogation on what user wants and it contains descriptions of a sensing task. Data is the collected or processed information of a physical phenomenon which is named using attribute-value pair. Gradient is a link a neighbor from which interest was received, and it is characterized by data rate, duration, and expiration metre which has derived from the received interest filed 2. A node, usually sink will be broadcasting interest to request data by diffusing interest through its neighbors. The interests are periodically refreshed by the sink. When this interest is received by the intermediate nodes, they cache for future use, or do in-network data aggregation or direct interest based on previous cached data. The source node sends the data back through the reverse path of the interest. When data is received by the nodes, they try to compare with the interest cache before. The data which matches the interest is drawn and then sent via the same path where the interest has received. Out of several paths between sink and the source, one path is selected by network by reinforcement. Once this path is selected, the sink sends the original interest again with smaller era interval so as to make the source node on the selected path to send data more frequently.Although directed diffusion has advantages that the protocol can in-network data aggregation and caching which saves energy but this protocol cannot not be applicable to all the applications of wireless sensor networks. The protocol can only be applied to such application which is query driven. It is not sui hedge for the applications such as forest fire detection or intrusion detection. Fig. 4, copied from 12 shows the working of the protocol.Rumor RoutingRumor routing 13 another variation of Directed Diffusion aims to direct the query to the nodes which have observed event rather than flooding the entire network 2. It is a log ical compromise between query flooding and event flooding 3. This protocol is only useful if the number of queries compared to number of events is between the two interaction points. See fig. 5, redrawn from 13.Rumor routing algorithms introduces an agent, a long live packet. An agent, which also contains an event remand like nodes, travels the network propagating information about local event to the distant nodes. The agent informs the nodes it encounters of any events it has observed on its way and at the same time it will synchronize its event dining table with the event table of encountered node. An agent will travel the network for certain number of hops and then die. All the nodes including an agent maintains an event table list that has event-distance pairs, as shown in fig. 6, copied from 13. So when a node generates a query for an event, the nodes that knows the route, can respond to the query by referring its event table 2. In this way, flooding the square network is a voided. Directional rumor routing is proposed in 14, which try to improve latency and energy consumption by considering query and event propagation in straight line instead of random walk in normal rumor routing.CougarCougar 15, 16 is a database approach for tasking sensor networks through declarative queries. Since in-network computation is much cheaper than transmission and communication between nodes, cougar approach proposes a loosely-coupled distributed architecture to support both aggregation and in-network computation. This helps in reducing energy consumption thereby increasing lifetime. The architecture introduces a query proxy layer in each sensor node which interacts both with network layer and application layers. The gateway node (where query optimizer is located) generates a query processing innovation after receiving queries from the sensor nodes. This query plan specifies both data race between sensor nodes and in-network computation plan at each separate sensor no de. The query plan also contains how to select a attraction for the query. The query plan can be viewed at non-leader node and at the leader node. Fig. 7 and fig. 8, redrawn from 15, show query plan at non-leader node (source sensor) and leader node respectively.Although, cougar provides solution to interact with the sensor nodes self-sufficient from the network layer, but the insertion of proxy layer at each sensor node introduce extra overhead for sensor node in terms of memory and energy consumption 2. Additional delay may be incurred with the relay trying to wait for the packets from other nodes for aggregation before sending to the leader node.ACQUIREACQUIRE 16 is a data-centric routing protocol aiming at large distributed databases. It aims at complex queries which comprise of several sub-queries that are combined by conjunctions or disjunctions in an arbitrary manner. The protocol sends an restless query packet into the network. This active query packet is sent by the sink , which takes random path or path predefined or guided. The node which receives this active query packet uses information stored within them to partially resolve the query. If the nodes do not have updated information, they gather the information from their neighboring nodes with the distance of d (look-ahead parameter) hops. When the active query is resolved completely, the response is sent back to the node which has issued the query. Some of the assumptions made in this protocol are 17 the sensors, with same transmission range are laid out uniformly in a region and they are stationary and do not fail.EAD Energy-Aware Data-Centric RoutingEnergy-Aware Data-Centric (EAD) 18 aims to construct a virtual pillar containing all active sensors, which is responsible for in-network data processing and relaying traffic. The radios of other nodes which are not in the virtual backbone are put off to conserve the energy. The sensor network is represented by a broadcast corner rooted at the gat eway and spanning all the sensors with large leaf nodes. In order to conserve power, the radios of these leaf nodes are put off while the nodes which are in virtual backbone are active for traffic relaying. The protocol tries to construct broadcast spanning tree network with maximum leaf nodes so that maximum energy can be conserved. The concept of EAD is to include the neighboring broadcast scheduling and the distributed competition among neighbors, based on residual energy 18. The efficiency of the protocol would be more when the size of the network is small. When the size of the network is large, execution time will be more since the execution process propagates from the sink to the integral network. Other protocol like the one proposed by Shah and Rabaey in 19 also aims at increasing network life time. They use network survivability as the main metric and propose to choose one of the multiple paths with a certain probability so that the whole network life time increases. But t he protocol assumes that each node is addressable with some addressing schemes.Information-Directed RoutingLocation-based ProtocolsSince sensor nodes have limited energy capacity, most of the routing protocols aim to reduce the consumption of energy in routing processes. In most of the protocols location of the sensor nodes are used to find the distance between two communicating pairs in order to find the best possible path with low energy usage. If location of a particular sensor node is known, query can be sent to that particular location only without sending to other regions which will reduce the number of transmission significantly 2. Location-based protocol makes use of the position information to relay data to the network rather than the whole network. In this section, we describe some of the location-based routing protocols proposed for wireless sensor networks.Minimum Energy Communication Network (MECN)Hierarchical-based Protocols