1. Energy Aware Fault Tolerant Shortest Minded Path SPIN (SPMS) Nishanth Reddy Kommidi Prajwal Panchmahalkar Department Of Computer Science Department Of Computer Science Texas Tech University Texas Tech University Lubbock, Texas, USA Lubbock, Texas, USA email@example.com firstname.lastname@example.orgAbstract— In this paper we present an energy efficient remainder of the protocol and data transfer can occur indata dissemination protocol for efficiently distributing the multiple hops using the lowest energy level. In thisdata through a sensor network. We also consider energy paper, we propose a protocol called EA-SPMS (Energyconsumption at each and every node in order to balance Aware SPMS) that balances the load on the relay nodesthe load in the sensor network and maintain energy between source and destination. We achieve this byefficient data disseminations. This paper works efficientlyeven in the face of node and link failures. Our work is using the fact that every node has the information of itsmotivated by the SPMS protocol in which every node has a neighbor’s zone along with its own zone. This protocolzone defined. If a node requests the data, the data is sent to is just an extension to SPMS; here also nodes canthe requested node using the shortest path. We propose a operate at multiple power levels. We run distributedprotocol called EA-SPMS (Energy Aware SPMS) in which Bellman Ford algorithm among the nodes in the zone, toevery node has a node defined by its maximum find out the routes (shortest paths) to other nodes in thetransmission radius and every node has the information of zone. Each node maintains routes to other nodes in theits neighbor’s zone and its own zone. The nodes which are zone and also maintains the energy that it consumes inin common to the other two neighboring nodes overhears receiving the ADV, sending the request and thenthe transmission messages and react only when the En-bit broadcasting the ADV it its zone neighbors, thenis set i.e. when the calculated energy at each node is lessthen threshold value. receiving the request and transmitting the data to the requested node every time it receives the adv message. Keywords- Sensor network, energy efficient, data Each node calculates the energy that it required todissemintaion process the above scenario. We maintain a fixed energy threshold value throughout the network lifetime. The En- I. INTRODUCTION Bit (Energy Bit) is set accordingly. En-bit set when the Wireless Sensor Networks have recently emerged as a calculated energy at each node is less then thresholdcore technology to be applied in home applications, value.military applications, and environmental applications.Sensor nodes are typically battery powered and sincereplacing or recharging battery is often very difficult, II. RELATED WORK AND MOTIVATIONreducing energy consumption and maintaining a load A. Related Workbalance between the nodes is an important design SPINconsideration for the sensor networks. Sensor nodes areused for gathering the data, such physical, environmental SPIN is proposed to solve the data implosion problem ofconditions from remote areas and disseminating them. flooding since a node transmits data to its neighbors The protocol called SPMS (Shortest Path Minded irrespective of whether the neighbor already received theSPIN) which is motivated by SPIN (Sensor Protocols for data via flooding. Nodes negotiate with their neighbors before transmitting data in SPIN to overcome thisInformation via Negotiation) reduces energy problem. SPIN guarantees only required data will beconsumption and end-to-end delay of SPIN. This was transmitted. SPIN uses high-level data descriptors calledachieved by the fact that nodes can operate at multiple meta-data in negotiation to determine if a node needs thepower levels and once the meta-data is initiated, the data prior to real data exchange.
2. SPIN involves the following steps: B. Motivation ADV- new data advertisement. A node broadcasts an SPMS reduces the energy consumption by transmitting advertisement message including metadata to its the data through the shortest path; this may result in neighbor nodes. overusing of a specific node, since the shortest path has REQ- Request for data. If a node requires the data, it been already selected. SPMS did not guarantee the sends a request message to the sensor node that sent energy efficiency in the case of node failure, since some the advertisement. other nodes in the network can no longer use the shortest DATA- Data message. When a node receives the path. Moreover the relay nodes in SPMS have high request message, it transmits the data to the additional overhead as they have to relay the data neighbors that have sent the requests. between the source and destination. SPMS did notSPIN disseminates data throughout the entire network by provide and solution when the node in shortest path failsthe repeated use these three steps. and the SCONE is not in the range of the node.SPMS III. DESIGN OF ENERGY AWARE SPMSSPMS (Shortest Path Minded SPIN) borrows the conceptof meta-data exchange from SPIN, and uses a multi-hopmodel for data transmission among the nodes with The idea is formed on the basis of the SPMS protocolvariable transmission power levels. In SPMS each node which implements the idea of three-way hand-shake ofhas its own zone. A zone for a node is the region that the SPIN protocol through metadata exchange and alsonode can reach by transmitting at the maximum power implements the shortest-path routing along with thelevel. Each node maintains a routing table for each of its relaying of intermediate nodes. SPIN however, suffersneighbors. The Distribute Bellman Ford (DBF) algorithm from a drawback that nodes that are relaying areis executed in each zone to form the routes. Each entry of constantly in communication and have a higher energythe routing table at each node has a destination field and overhead due the relaying. The relay nodes have tothe cost of going to the destination through each of its constantly relay the data between a given pair of sourceneighbors. and destination for communication, and SPMS has not considered the energy constraints at relay node.SPMS involves the following steps: It involves a metadata exchange, similar to that in SPIN, if a node has a data to send, broadcasts an advertisement message to its neighbor nodes in the same zone. If a node wants the data, it sends a requests message through the shortest path.To send the data through the shortest path, if the advmessage received by the node is not the next hopneighbor in the computed shortest path., then it shouldwait for a certain period of time before sending therequest message. After each node sends a requestmessage, it receives the data through the shortest path. Ifthere is no adv message during the fixed period of time,the node sends the request message to the source node. Whenever a node in between the source node andthe destination node fails, the current node sends the Fig1: A sample network. Each node maintains arequest message to the node, from which it initially cost table associated with it to reach to its neighborreceived an adv message instead of using the shortest within the zone along with the cost table of itspath. If a node that broadcasts the adv message fails, neighbors.there is no way to receive the data. Therefore, in thisprotocol the destination node maintains the primary In EA-SPMS (Energy Aware SPMS) we consider thatoriginator node (PRONE) and a secondary Originator each node maintains the routing tables of costs of theNode (SCONE). SCONE is the alternative node that can nodes within its zone along with the cost table tables ofbe used to request the data when the PRONE fails. the neighbors in its zone, which underlies our assumption that the overhead of communication is too high than the storage overhead .
3. In EA-SPMS we call the relay nodes as smart relay nodes, smart relay node overhear the REQ and look up intowhich are aware of their own residual energy and the their tables to check if the destination node and theenergy they have to spend to relay the data between the PRONE of the node are in its range and if they both aresource and the destination. And based on the energy costs present these smart relays calculate their own En-Bit andother nodes in the zone can take over the route if they if their En-bit is greater than the actual relay node, theyprove effective in energy balance and fault tolerance. take over the route and send request to the PRONE and IV. THE PROPOSED APPROACH energy balance is achieved. Also relay nodes doesn’t have to continuously When smart-relays get the REQ from the destination participate in the communication as other relay nodesthey estimate the cost they have to spend in relaying the can take over the path to balance the energydata by utilizing the data present in the REQ data; the consumption among with relay nodes. Through smart-REQ packet contains the data about the data that is relay nodes we theoretically assume that the energy loadrequested along with the source and destination of the balance is effectively achieved and the life of thecommunication, the smart-relays use this data to calculate network is increasedthe cost and estimate the energy they will be left overafter the relaying and calculate the Energy bit B. Node Failure caseEr = Ep – (Erec + Et) The node failure case is similar to the energy aware case, just the difference is that the no REQ is heard from the node, however nodes which are in common zone withWhere, the failed node, destination node and the PRONE of the failed node can overhear the REQ from the destinationEr = energy expected to remain after the relaying. node and doesn’t hear any REQ from the failed node, soEp = energy present at the node at current time ie, when it they take over the route just as the Energy Aware case.receives the REQ from the destination nodeErec = Energy needed to spend on receiving the data from EA-SPMS is effective even in case where if the SCONEthe source. is not in range of the destination node; as we maintain a routing table of neighbors in two-hops it can proveEt = Energy needed to spend on transmitting the data to effective beyond SPMS in being more fault tolerant.the destination node.Based on the Er value calculated the smart relay node setsa En-bit (Energy bit) of 4bits which constitute the 10 V. REFERENCESlevels which we considered for the energy balance in the 1. Negotiation-based protocols for disseminatingrelay nodes. The smart relay adds this En-bit in its information in wireless sensor networks,request to its PRONE node. We set a threshold value for Wireless Networks, 2002, J. Kulik, W.these En-bits based on which if the En-Bit is below the Heinzelman, and H. Balakrishnanthreshold value the node which receives this REQ packet 2. Fault Tolerant Energy Aware Datagoes into a waiting state. Meanwhile the other nodes in Dissemination Protocol in Sensor Networks,the range of the smart relay overhear and look up into DSN 2004, Gunjan Khanna, Saurabh Bagchi,their tables and calculate if they have more En-bit value Yu-Sung Wuthan the actual smart-relay in the path and if they have 3. Performance Comparison of SPIN based Push-more En-bit than the actual node they take over the route Pull Protocols, WCNC 2007, Ravish Khosla,and send REQ to its PRONE. Xuan Zhong, Gunjan Khanna, Saurabh Bagchi,A. Energy Aware case and Edward J. CoyleThe smart relays send the En-bit along with the REQpacket to its PRONE node, the prone node based on theEn-bit if it is below threshold goes into a waiting state.Meanwhile the other nodes which are in the range of this