Extending the Network Lifetime Using Optimized Energy Efficient Cross Layer Module (OEEXLM) in Wireless Sensor Networks

doi:10.4236/wsn.2009.11005

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Wireless Sensor Network, 2009, 1, 1-60

Published Online April 2009 in SciRes (http://www.SciRP.org/journal/wsn/).

Extending the Network Lifetime Using Optimized Energy

Efficient Cross Layer Module (OEEXLM) in Wireless

Sensor Networks

T. V. Padmavathy

Department of Electronics and Communication Engineering, SSN College of Engineering, Chennai, India

Email: Padmavathytv@ssn.edu.in

Received February 11, 2009; revised March 10, 2009; accepted March 13, 2009

Abstract

In wireless sensor network, the primary design is to save the energy consumption as much as possible while

achieving the given task. Most of recent researches works have only focused on the individual layer issues

and ignore the importance of inter working between different layers in a sensor network. In this paper, we

use a cross-layer approach to propose an energy-efficient and extending the life time of the sensor network.

This protocol which uses routing in the network layer, and the data scheduling in MAC layer. The main ob-

jective of this paper is to provide a possible and flexible approach to solve the conflicts between the require-

ments of large scale, long life-time, and multi-purpose wireless sensor networks. This OEEXLM module

gives better performance compared to all other existing protocols. The performance of OEEXLM module

compared with S-MAC and directed diffusion protocol.

Keywords: Routing, Medium Access Control, Life Time of the Network, Energy Efficiency, OEEXLM

Module, Wireless Sensor Networks

1. Introduction

Wireless sensor network consists of large number of

sensor nodes are randomly distributed in a region. Each

node has a limited energy supply and generates informa-

tion when ever event occurs that needs to be communi-

cated to a sink node. The focus of this paper is on the

computation of optimal energy usage for data transfer

and link schedule that maximize the network lifetime.

However most wireless sensor network energy consump-

tion operations involve sensing, computing, and communi-

cating [1]. Generally, communication between nodes con-

sumes more energy than local processing or collecting data

operation. The geographical nature of the deployment

space of nodes makes quasi impossible the replacement or

the recharging operations of batteries. The challenge is to

economize energy inside every node in order to maintain

as long as possible the network functionality.

2. Related Works

Many research works are developed for energy effi-

ciency at each layer of protocol stack by proposing new

algorithms and protocols. In particular, MAC layer was

of great interest for many researchers because it is con-

sidered as an important source of energy wastage such

as overhearing, collision, control packet overheads and

idle listening [2].

In order to decrease or if possible to eliminate these

various sources of energy wastage, several protocols has

been proposed during last years and which are divided

into two main classes: Schedule based protocol TDMA

and Contention based protocol.

In TDMA protocols [3] are employed to avoid colli-

sions by associating a slot time for each sensor node in a

given cluster. This protocols more complex in the WSN

where the nodes in general have a same priority and very

limited resources. The Contention-based protocols are

known as CSMA-based are usually used in the multi-

hop wireless networking. But this protocol generates

collisions due to these useless retransmissions which

cause energy consumption wastage and time consuming

in data transmission.

Some of the power control problems are discussed in

[4,5]. Approaches at MAC layer are Dermikol et al. [4]

infers that some pros and cons of the some of the exist-

ing protocol. One of the first attempts at MAC protocol

for WSN is PAMAS, which reserves battery power in-

28 T. V. PADMAVATHY ET AL.

telligently powering off users that are not actively

transmitting or receiving packets. This protocol de-

creased the energy consumption of the network but

maximum latency occurs. Raghavendra et al. [5] the

Power Aware Medium Access protocol and Signaling

(PAMAS) is a CSMA based protocol in which the nodes

that are not actively transmitting or receiving should

power themselves off. The protocol requires the nodes to

have two separate channels (control and data), which

will require two radios at each node increasing the cost,

size and complexity of the sensor design.

Existing MAC protocol [6,7] turn off the transceiver

when there is no communication between the nodes also

the power savings in these papers results reducing the

idle listening power but also decreasing the collisions. In

these papers they proposed adaptive listening incurs

overhearing. Sleep and listen periods are predefined and

constant, which decreases the efficiency of the algorithm

under variable traffic load.

A new generation of MAC protocols that is Cross-

layer MAC protocols using several layers in order to

optimize energy consumption has been emerged. These

layers can be divided into interaction mode or unification

mode. In the interaction mode, the MAC protocol is built

by exploiting the data generated by other adjacent layers.

Approaches at network layer in WSNs are mostly

used to implement the routing of the incoming data, as

quoted in [8]. It is known that generally in multihop

networks the source nodes cannot reach the sink directly.

Therefore, intermediate sensor nodes have to relay their

packets. Generally, the implementation of routing tables

offers the solution. These routing tables contain lists of

node options for any given packet destination Definition

of the routing tables is the task of the routing algorithm

along with the help of the routing protocol for their con-

struction and maintenance.

MAC-CROSS Protocol [9] is an example of Cross-

layer approach which allows the interaction between

MAC and information of the network layers by making

only the communicating nodes in listening mode and by

putting other nodes into sleep mode. In order to avoid

collisions, MAC-CROSS uses the control messages

RTS/CTS/ACK. On the other hand, a Cross-layer design

mode by unification requires the development of only

one layer including at the same time functionalities of

considered layers.

In this paper, a unified cross layer module XLM [10]

is developed which achieves efficient and reliable event

communication between the nodes with minimum en-

ergy expenditure. But in this protocol the end-to-end

delay increases for low value duty cycle. When the duty

cycle is low =0.1, 14% of the transmitted packets are

dropped due to retransmission timeout. Because sender

nodes cannot find any neighbors that satisfy the constraints.

Weiyan Ge et al. [11] addressed the rate optimization

for multicast communications at the media access con-

trol (MAC) layer, and explore transport layer erasure

coding to enhance multicast reliability in wireless sensor

networks. In this approach they are not addressed the

energy consumption and end-to-end delay.

3. Proposed OEEXLM Module

The proposed cross layer approach replaces the entire

traditional layer protocol architecture that has been so

far used in WSNs. In this protocol we integrate the me-

dium access control and routing to improve the perform-

ance of the network. The communication in OEEXLM

module is based on initiative concept. This module al-

lows the each node to decide whether it can participate

in communication or not. Consequently, this protocol

uses adaptive receiving, stagger scheduling algorithm

and logical link decision algorithm.

A node starts a transmission by transmitting to its

neighborhood an RTS packet to indicate that it has a

packet to send. Upon receiving an RTS packet, each

neighborhood node i decide to participate to communi-

cation or not, that decision can be determined by an ini-

tiative “I” defined as follows:

I= 1

thd

rev rev

TAR T

otherwise

⎧>+

⎛⎞

⎪⎜⎟

β= γ=γ

⎪⎜⎟

⎨⎜⎟

⎝⎠

⎪

⎪=

⎩

(1)

The initiative is set to 1 if all four conditions are true

or satisfied. Out of four conditions, the first two condi-

tions related to MAC layer and next two conditions re-

lated to network layer. The first condition checks event

β occurs or not. If

= 1 then the remaining three condi-

tions checked by the node, otherwise the nodes are go to

sleep mode.

Because of this, idle listening and overhearing are

avoided. The second condition is adaptive receiving

scheme, the receiver node wait for TA seconds if the

node does not receive any packets from upper layer it

goes to sleep state. The third condition is the node will

check the buffer size γth if the size is less than threshold

it will choose the alternate path to reach the destination.

Fourth condition is that source node from upper layer

checks the lower layer receiver node energy if it is

greater than threshold Ethd

rev then it will transmit packet

otherwise it will choose the alternate path.

Using this initiative concept, OEEXLM module over-

comes collision, overhearing, idle listening and improve

the throughput, link reliability and extend the life time

of the network.

3.1. Basic Terms Used in OEEXLM

The following assumption can be considered for OE-

EXLM protocol to study the performance. The network

topology used in this protocol is grid architecture. Data

flows from n layer to n-1 layer until the data packet

reached the destination. For simulation MICA2 mote

specification is considered. In this protocol the value of

duty cycle is denoted by

and is defined as ratio of the

time a node is active. The duty cycle is varied with re-

T. V. PADMAVATHY ET AL. 29

spect to data transmission. The sleep time for each node

leep

T sec. The listen period of each node is less than or

equal to transmission period of upper layer. Transmis-

sion period each layer is 50ms. With in 50ms if lower

layer node does not receive any data from upper layer it

will wait for TA sec and go to sleep.

3.2. Initiation of Transmission

When the event occurs that is

=1 layer n node has a

data packet to transmit, it sends RTS signal to the

lower layer, the lower layer sends the CTS signal to the

upper layer with response the CTS signal the layer n

sends the data to the layer (n-1) for 50ms.During the

receiving period, if a node senses that the channel is

idle and its neighbours are not communicating for a

time TA, it will go to sleep until its subsequent sending

periods. After receiving the packet from n layer, the n-

1 layer route the packets to the destination, each source

node determines a path to the destination by selecting a

lower layer node under its coverage randomly. Thus

messages flow in the correct direction, but do not use

the same path every time. Thus this data exchange

scheme provides both collision avoidance and reliable

retransmission.

4. Mechanism of OEEXLM

Figure 1 explains the mechanism of OEEXLM module. In

this module we integrate the MAC and network layer. In

MAC layer we proposed Power Efficient MAC protocol

which is used to overcome idle listening, collisions, Hid-

den terminal problem, and also to provide a low latency

compared to other existing MAC protocols. The PE-MAC

uses the three algorithms to achieve the energy efficiency.

4.1. Clock Synchronization Algorithm

In clock synchronization algorithm layer n comprises the

source nodes. Initially the nodes in layer n are in sending

mode for 50ms while those in the layer (n-1) are in re-

ceiving mode. The remaining nodes are in sleep state.

Assume that the source nodes generate packets (layer-n).

As the next layer nodes are in the receiving mode, the

source nodes can transmit the packets directly without

checking the status of the lower layer nodes. The pack-

ets are stored in the buffer space of the lower layer

nodes. Once the receiving period of layer (n-1) nodes

ends, the sending period for layer (n-1) starts. The layer

(n-2) nodes shift from sleep mode to receive mode. The

remaining nodes enter the sleep mode.

4.2. Logical Link Decision Algorithm

The LLD algorithm is implemented in this protocol to

ensure that two source nodes do not transmit the packets

to the same receiver at the same time. This algorithm is

implemented initially when each source node determines

a link to the sink. When all the source nodes determine

their links, the links are compared to ensure that there is

no overlap in the existing links. If there is an overlap,

the LLD algorithm uses a logical link decision to get the

new link to the sink.

4.3. Adaptive Receiving

In Adaptive Receiving algorithm, layer n sends RTS

packet to the lower layer n-1, the lower layer sends the

CTS signal to the upper layer n. With response the CTS

signal from layer n-1, the layer n sends the data to the

layer n-1 for 50ms.Adaptive receiving scheme employs

a time interval TA to handle traffic varies.

During the receiving period, if a node in the n-1 layer

senses that the channel is idle and data from n layer are

not communicating for a time TA, it will go to sleep.

Suppose with in 50ms if the layer n-1 senses any data

from the upper layer n it wakes up and receive the data.

This adaptive receiving scheme reduces the packet drop

and improves the throughput of the network.

In network layer we proposed two algorithms: a con-

gestion control and alternate path algorithm. These two

algorithms are used to improve the lifetime of multihop

sensor network by avoiding the collision.

4.4. Alternate Path Algorithm

In alternate path algorithm, each has routing table. Be-

fore route the data packet each source finds a multiple

path to the sink. In this each source node initiate HELLO

message to all lower layer nodes.

The HELLO message contains source ID, type of

node whether it is sink or intermediate node and energy

level which is shown in Figure 2.

Each node in the lower layer updates it table once it

receives the HELLO message. If any node in lower layer

gets more than one HELLO message it sends the nega-

tive acknowledgement NACK signal to the correspond-

ing source node. Then that particular source node

chooses the alternate path to reach the sink.

After setting an alternate route the nodes in the rout-

ing path check its energy level of receiving node. If the

energy level less than the threshold Ethd

rev again the node

choose the alternate path by sending HELLO message

and the routing table is updated.

4.5. Congestion Control Mechanism and

Algorithm

The congestion in the network is due to two traffic. One

is due to generated packet that is whenever node detect

the events it will generate the data packets and that is to

be transmitted to the destination through intermediate

nodes. The rate of generated packets at the node i is de-

noted by

30 T. V. PADMAVATHY ET AL.

Is Event occurs

Packet arrives at Layer n

Yes

Finding several paths

for each Source to

Destination

Selection of

Non-overlap shortest

path for each source

Transmit data

Finished

Tran smittin g

Deployment of Sensors

in the Application area

Sensors Activated

If (TA > R+T)

Set Transmission Time =

50m s

Send RTS packet to

the Routing node in

Layer-n-1

If Data

Oc curs

Data transmission starts

after receiving the CTS

packet

Set Receiving Time =

50ms

Receive Data

Is Buffer size

Source node sends

"HELO" Packet to n-1

layer

Is Overlap

occu rs

Ye s

Select the

Alternate path

Yes

Goes to

Sle ep

Yes

Energy

Level

Yes

Ye s

Figure 1. Mechanism of OEEXLM.

Since the network is a multi hop each nodes plays

dual role that is it act as source as well as router. During

the transmission each node in lower layer receives the

data packet from the upper layer until the data packet

reached at the destination. These packets are referred as

relay packets. If the n-1 layer node receive the data

packets from layer n the rate of relay packet of node i of

n-1 layer is ,1

in−

λ. The input rate of the buffer for the

node i is depends on the rate of relay packets ,1

−

λ and

the rate of generated packets

i. In OEEXLM module

the rate of input packet at node i’s buffer αi, can be

represented as

.,1

iiin−

α=λ+λ (2)

The node is active for a fraction of duty cycle

50ms. Hence the average time taken a time to transmit

and receive data packet can be given by

(

)

txii pkt

Tet

+α⋅ (3)

rxi npkt

−

=λ (4)

where pkt

t is the average time taken to successfully

transmit a packet to another node and i

e is the error

packet rate.

The proposed OEEXLM module avoids packet drops

due to congestion by not allowing upper layer nodes to

transmit data packet if there is not available buffer size

this is can be controlled by congestion control algo-

rithm. A lower layer node changes the path of transmis-

sion based on its buffer status. During transmission, the

lower layer node i allow Pi packets to be transmitted by

the upper layer nodes. Figure 3 shows the buffer queue

model of the node.

Given the condition that the lower layer node has pro-

portionally higher probability to access the medium,

T. V. PADMAVATHY ET AL. 31

Source ID Type of Node Energy level

2 Byte 1 Byte 4 Byte

Figure 2. HELLO message packet format.

Figure 3. Buffer queue model.

even then the lower layer node may not be able to for-

ward all i

P packets. So, in the next transmission, the

lower layer node will have some packets from the previ-

ous transmission, which might cause Congestion within

few successive transmissions. Therefore, for each

transmission upper layer nodes check the routing table if

the buffer size

less than the buffer threshold thd

up-

per layer node takes the alternate path. Maximum num-

ber of packet hold by the buffer is buff

N. The transmis-

sion only occur when

>thd

thd

=byff

N≥0

∑ (5)

where buff l

−

As a result of congestion control algorithm, the OE-

EXLM module avoid the layer to layer congestion occur

in the networks. Because of this energy consumed by the

node is reduced there by improving the life time of the

network.

The medium control access scheme uses three algo-

rithms to improve the energy efficiency and in network

layer we use two algorithms to improve the life time of

the networks. These two layers are integrated by using

initiative conditions as per Equation (1).

5. Network Topology

Figure 4 shows the data flow for the OEEXLM module.

The nodes in the network operate in three different

modes-sleeping, receiving and sending. Each node goes

to sleep periodically to save energy and then wakes up

and listens to see if any other node wants to talk to it.

During sleep, the node turns off its radio; therefore the

energy waste due to idle listening can be reduced.

The nodes with same layer-count are given the same

schedule, and the sending and receiving periods are

staggered layer by layer such that when one node is in

sending mode, its lower-layer node is in receiving mode.

After receiving a message from an upper-layer node,

each node can transmit it to the lower-layer node in the

subsequent sending period. So a packet can be transmit-

ted to sink nodes through multi-layers fleetly and the

end-to-end latency is reduced.

5.1. Performance Evaluation

The Table 1 shows the simulation setup used for simula-

tion.

5.1.1. Latency Vs Network Area (MAC)

Figure 5 infers that in S-MAC a node has to wait till its

neighbouring node as to awake to transmit the message

to it. This results there will be some amount of delay in

S-MAC protocol, which is absent in OEEXLM module.

In OEEXLM module whenever a node is in send state,

the lower layer node is in receiving state. So the source

node can transmit the message to the lower layer without

checking whether the lower layer node is listening or

sleeping mode. Hence the source node can transmit its

message fleetly to the sink through multi layers.

5.1.2. Energy Consumption Vs Network Area (MAC)

The Figure 6 infers that depicts the energy consumption

of S-MAC and OEEXLM module. The comparison is

made for a simulation setup with ten layers, ten nodes in

each layer and a four sink. The graph shows that OE-

EXLM module protocol uses less energy than S-MAC.

This is because the idle listening dominates the energy

consumption in S-MAC protocol but TA can make OE-

EXLM module go to sleeping mode earlier, and the en-

ergy consumption is reduced. The energy consumption

of OEEXLM module is 35% -83% les than existing S-

MAC protocol.

5.1.3. Latency Vs Number of Hop (MAC)

The Figure 7 shows that the latency encountered in OE-

EXLM module compared with that in S-MAC with respect

to number of hops. Obviously the latency of OEEXLM

Table 1. Simulation setup.

Parameters Value

Transmission Range 250 m

Network Area 100 x 100

Number of Sensors 100- 1500

Packet rate 5 pkt/sec

Packet size 512 bytes

Radio Bandwidth 76kbps

Transmitting Power 75mW (270J)

Receiving Power 36mW (129.6J)

Power Consumption in Sleep mode 100μ W (0.36 J)

Sending and Receiving Slot 50msec

Type of mote Mica2

Inital energy of sensor node 2KJ

Energy Threshold Ethd 0.001mJ

buff

32 T. V. PADMAVATHY ET AL.

Figure 4. Data flow diagram for OEEXLM module.

Figure 5. Latency vs network area.

module is lesser than that in the S-MAC because of

staggered scheduling algorithm. In S-MAC a node has to

wait till its neighbour is awake to transmit the message

to it. This problem is not occurring in OEEXLM module.

In OEEXLM module whenever a node is in send state,

the lower layer node is in receiving state. So the source

node can transmit the message to the lower layer without

checking whether the lower layer node is listening.

Hence the source node can transmit its message fleetly

to the sink through multi layers.

5.1.4. Latency Vs Number of Hops (Routing)

Figure 8 infers the delay as a function of the number of

nodes in the WSN. The delay increases with the number

of hops increasing. Our simulation shows the average

delay of the proposed protocol is better than that of the

directed diffusion. This is because in OEEXLM module,

for each transmission each node in the routing checks

the buffer condition, so that no queue of data occurs in

the buffer.

Due to alternate path algorithm the shortest delay oc-

cur compared to other schemes. As we expected, data

packets are routed through different node-with the help

of proper design of algorithm in routing. Hence, the net-

work congestion can be avoided.

5.1.5. Energy consumption Vs Number of Nodes

(Routing)

Figure 9 infers that energy consumption per node ver-

sus number of nodes. The value of node energy con-

sumption gives the average energy dissipated by the

node in order to transmit the packet from source to

drain. The same metric is used in [6] to determine the

energy efficiency level of WSNs. It is calculated as

follows:

()

e initiale resi

NodeEnergy Consumption

NdataP

−

=∑

∑ (6)

where N is the total number of nodes, initialei, initial

energy of nodes, resiei, is the residual energy of the

nodes, S is the number of sinks and

P is the number

of data packets received by the sink j.

Figure 6. Energy consumption vs network area.

Figure 7. Latency vs number of hops.

Layer n

Layer n-1

Layer 1

Sink

T. V. PADMAVATHY ET AL. 33

Figure 8. Comparison of latency vs number of hops with DD.

Figure 9. Energy consumption vs number of nodes.

The simulation result infers that there is lower node

energy consumption in CRLS protocol over the other

schemes., The energy consumption of nodes in OE-

EXLM module is 34% to 84% lesser than when com-

pared with directed diffusion. This results shows that the

energy efficiency of OEEXLM module is stable and has

little impact by the increase of the network size, while

the performance of other schemes degrades with larger

network size.

5.1.6. Network Life Time

The system lifetime is defined as the number of rounds

for which 75% of the nodes are still alive. CRSL The

transmitted and received energy costs for the transmis-

sion of a k-bit data message between two nodes sepa-

rated by a distance of r meters are given by Equations (6)

and (7), respectively.

() ()

ttxamp

Ek,rEk Erk=+ (7)

()

rrx

Ek Ek= (8)

In Equation (7) )( r,kEt denotes the total energy dis-

sipated in the transmitter of the source node, while

()

Ek in Equation (8) represents the energy cost in-

curred in the receiver of the destination node. Parame-

ters tx

E and rx

E are per bit energy dissipation for

transmission and reception, respectively, and )( rEamp

denotes the energy required by the transmitted amplifier

to maintain an acceptable radio for transferring data re-

liably. The free-space propagation model is applied, and

the transmit amplifier )(rEamp is given by Equation (9)

amp FS

Er=ε (9)

where e

S is the transmitted amplifier parameter. The

set of parameter given in [7,8].

e =10 pJ/b/m2.

From Figure 8, we infer that the network lifetime is

increased by using the alternate path and congestion

control algorithm. The network lifetime is given in terms

of rounds till which 75% of nodes are alive. A network

is assumed to be useless when one of the sensor’s en-

ergy is below the threshold.

5.1.7. Data Packet Delivery Ratio

Data packet delivery ratio can be calculated as the ratio

between the number of data packets that are sent by the

source and the number of data packets that are received

by the sink. It can be denoted as R

Successfully delivereddata

Data Delivery RatioRequired data

(10)

This parameter R indicates both efficient of the rout-

ing protocol and the effort required to receive data. In

the ideal scenario the ratio should be equal to 1. If the

ratio falls significantly below the ideal ratio, then it

could be an indication of some of the packet dropped

because of faults in the protocol design. However, if the

ratio is higher than the ideal ratio, then it is an indication

that the sink receives a data packet more than once. It is

not desirable because reception of duplicate packets

consumes the more energy. The relative number of du-

plicates received by the sink is also important because

based on that number the sink, can possibly take an ap-

propriate action to reduce the redundancy.

Figure 11 shows the data packet delivery ratio of DD

and OEEXLM modules. To eliminate packet loss we use

a rate of 5 packets/second. It is found that the delivery

ratio of the two protocols increase as the node density

increases. When node density is high, there are more

nodes available for data forwarding, and this increases

the delivery ratio. Directed diffusion protocol offers less

packet delivery rates, compared to OEEXLM module

because it does not adapt well its behavior to network

size increase. The OEEXLM module has maintained

constant delivery rates throughout the simulated scenar-

ios because the paths are selected based on the energy

availability and buffer size.

34 T. V. PADMAVATHY ET AL.

Figure 10. Network lifetime.

Figure 11. Packet delivery ratio vs number of nodes.

Figure 12. Performance variations with respect to buffer size.

5.2. Performance Variations with Respect to

Buffer Size

Figure 12 shows the performance variations when the

buffer size varies from 50 bytes to 300 bytes. When the

buffer size is 50 bytes number of packets reached at the

destination is minimum because of congestion but

packet delay is minimum. When the buffer size 300

bytes the number of packets dropped is minimum due to

large buffer and the average delay per packet increases

due to the increased queuing delay.

5.2.1. Packet Loss with Respect Buffer Size

Figure 13 infers that packet loss get reduced due to in-

creasing buffer size. The number of packets dropped due

to buffer overflow in the case of the OEEXLM module

almost zero. This is because each time after receiving

the packets from upper layer the buffer size is calculated

and updated in the routing table. Depending on updated

value the routing path algorithm send the HELLO mes-

sage to the other nodes in the routing.

5.2.2. Packet Delay with Buffer Size

Figure 14 shows Packet delay Vs buffer size. The graph

infers that as the buffer size increases the average delay

per packet increases due to the increased queuing delay.

Figure 13. Packet loss vs buffer size.

Figure 14. Packet delay vs buffer size.

T. V. PADMAVATHY ET AL. 35

When the buffer size is 120 bytes, packet delay is only 4

second from source to destination. When the buffer size

is 300 bytes length the delay is 12 seconds because of

queuing delay. From this graph, we find that as the

buffer size increases the packet delay also increases. But

throughput is maximum because the packet drop is

minimum by compromising the delay.

6. Conclusions and Future Work

In this paper we presented the Cross-Layer Design to

improve the performance of the wireless sensor net-

works. This protocol design is used to give the direct

interactions between the Network layer and the MAC

layer. The traditional Network layer and MAC layer

have been removed, thus simplifying the protocol stack.

Simulation results that our proposed scheme has higher

node energy efficiency, lower average delay and control

overhead than the directed diffusion protocol and S-

MAC protocol. The energy consumption of nodes in

OEEXLM module is 34% to 84% lesser than when

compared with directed diffusion. Further the network

life time is 78% improved compared to DD protocol. In

future we are going to extend the OEEXML design to

Physical layer.

7. References

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