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
nishanth.kommidi@ttu.edu
prajwal.panchmahalkar@ttu.edu
Abstract— In this paper we present an energy efficient remainder of the protocol and data transfer can occur in
data dissemination protocol for efficiently distributing the multiple hops using the lowest energy level. In this
data through a sensor network. We also consider energy paper, we propose a protocol called EA-SPMS (Energy
consumption at each and every node in order to balance Aware SPMS) that balances the load on the relay nodes
the load in the sensor network and maintain energy
between source and destination. We achieve this by
efficient data disseminations. This paper works efficiently
even in the face of node and link failures. Our work is
using the fact that every node has the information of its
motivated by the SPMS protocol in which every node has a neighbor’s zone along with its own zone. This protocol
zone defined. If a node requests the data, the data is sent to is just an extension to SPMS; here also nodes can
the requested node using the shortest path. We propose a operate at multiple power levels. We run distributed
protocol called EA-SPMS (Energy Aware SPMS) in which Bellman Ford algorithm among the nodes in the zone, to
every node has a node defined by its maximum find out the routes (shortest paths) to other nodes in the
transmission radius and every node has the information of zone. Each node maintains routes to other nodes in the
its neighbor’s zone and its own zone. The nodes which are zone and also maintains the energy that it consumes in
in common to the other two neighboring nodes overhears receiving the ADV, sending the request and then
the transmission messages and react only when the En-bit
broadcasting the ADV it its zone neighbors, then
is set i.e. when the calculated energy at each node is less
then 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 to
dissemintaion 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 threshold
core technology to be applied in home applications, value.
military applications, and environmental applications.
Sensor nodes are typically battery powered and since
replacing or recharging battery is often very difficult, II. RELATED WORK AND MOTIVATION
reducing energy consumption and maintaining a load A. Related Work
balance between the nodes is an important design SPIN
consideration for the sensor networks. Sensor nodes are
used for gathering the data, such physical, environmental SPIN is proposed to solve the data implosion problem of
conditions 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 the
SPIN) which is motivated by SPIN (Sensor Protocols for data via flooding. Nodes negotiate with their neighbors
before transmitting data in SPIN to overcome this
Information via Negotiation) reduces energy
problem. SPIN guarantees only required data will be
consumption and end-to-end delay of SPIN. This was
transmitted. SPIN uses high-level data descriptors called
achieved by the fact that nodes can operate at multiple meta-data in negotiation to determine if a node needs the
power 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 not
SPIN disseminates data throughout the entire network by provide and solution when the node in shortest path fails
the repeated use these three steps. and the SCONE is not in the range of the node.
SPMS
III. DESIGN OF ENERGY AWARE SPMS
SPMS (Shortest Path Minded SPIN) borrows the concept
of meta-data exchange from SPIN, and uses a multi-hop
model for data transmission among the nodes with The idea is formed on the basis of the SPMS protocol
variable transmission power levels. In SPMS each node which implements the idea of three-way hand-shake of
has its own zone. A zone for a node is the region that the SPIN protocol through metadata exchange and also
node can reach by transmitting at the maximum power implements the shortest-path routing along with the
level. Each node maintains a routing table for each of its relaying of intermediate nodes. SPIN however, suffers
neighbors. The Distribute Bellman Ford (DBF) algorithm from a drawback that nodes that are relaying are
is executed in each zone to form the routes. Each entry of constantly in communication and have a higher energy
the routing table at each node has a destination field and overhead due the relaying. The relay nodes have to
the cost of going to the destination through each of its constantly relay the data between a given pair of source
neighbors. 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 adv
message received by the node is not the next hop
neighbor in the computed shortest path., then it should
wait for a certain period of time before sending the
request message. After each node sends a request
message, it receives the data through the shortest path. If
there 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 and
the destination node fails, the current node sends the Fig1: A sample network. Each node maintains a
request message to the node, from which it initially cost table associated with it to reach to its neighbor
received an adv message instead of using the shortest within the zone along with the cost table of its
path. If a node that broadcasts the adv message fails, neighbors.
there is no way to receive the data. Therefore, in this
protocol the destination node maintains the primary In EA-SPMS (Energy Aware SPMS) we consider that
originator node (PRONE) and a secondary Originator each node maintains the routing tables of costs of the
Node (SCONE). SCONE is the alternative node that can nodes within its zone along with the cost table tables of
be 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 into
which are aware of their own residual energy and the their tables to check if the destination node and the
energy they have to spend to relay the data between the PRONE of the node are in its range and if they both are
source and the destination. And based on the energy costs present these smart relays calculate their own En-Bit and
other nodes in the zone can take over the route if they if their En-bit is greater than the actual relay node, they
prove 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 nodes
they estimate the cost they have to spend in relaying the can take over the path to balance the energy
data 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 load
requested along with the source and destination of the balance is effectively achieved and the life of the
communication, the smart-relays use this data to calculate network is increased
the cost and estimate the energy they will be left over
after the relaying and calculate the Energy bit B. Node Failure case
Er = 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 with
Where, the failed node, destination node and the PRONE of the
failed node can overhear the REQ from the destination
Er = energy expected to remain after the relaying. node and doesn’t hear any REQ from the failed node, so
Ep = 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 node
Erec = Energy needed to spend on receiving the data from EA-SPMS is effective even in case where if the SCONE
the source. is not in range of the destination node; as we maintain a
routing table of neighbors in two-hops it can prove
Et = 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 sets
a En-bit (Energy bit) of 4bits which constitute the 10 V. REFERENCES
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