19

CHAPTER 2

REVIEW OF LITERATURE

Localization in WSN has been studied in various research works and

it is implemented using various algorithms for different applications for

improving the performance of the network. For several reasons, the market

for wireless data services has grown at a much slower rate than wireless

voice. Until recently, portable data devices were bulky, required heavy

batteries, and did not have integrated networking. Wireless services have

also had to contend with narrow bandwidths, high access latency, and

frequent disconnection. Added to this were inadequate coverage, expensive

services, and perceived security problems.

The positioning of the signal strength is the major impact of WSN.

The node communication at every level based on the signal strength. In the

past decades, communications of data between the nodes are very difficult

task to find the localization. Localization algorithms can be categories into

two parts: Range based and Range free. In range based algorithms, node

measure the distance with some specific hardware. These measurements are

specified that triangulation and trilateration, which are defined in the

coordinating positions. The Range free algorithms require their location

estimates and ideal range of sensors. The range free method is more cost

effective because they do not require any specialized hardware.

20

SDMA divides the geographical space, where the users are located,

in smaller spaces. The key element of the design is a one-to-one mapping

between the space divisions and the bandwidth divisions of time slots and

frequency divisions described by Soheila V. Bana et al.(2001). They

provided collision-free access to the communication medium for the users,

and thereby, facilitate ad hoc communication address resolution amongst the

users.

C. Elam et al. (2004) illustrated the method and apparatus of SDMA

receiver has consistently with this invention received a plurality of receiving

elements, whereas each transmitted signal has different spatial location.

They also describe the signal position to form a combined signal derived

from the plurality of receives element signals and detect each of the plurality

of transmitting signals from the combined signal by different spatial

location. With this invention, each method converts the plurality of

modulation signal and phase modulation. The combination of these two

methods generates expected signals and cross correlate the combined signal

with the transmitted signals. In SDMA, a system classified the two signals,

one is user signal and another one is other signals. This signal sometimes

referred to as spatial filtering. When two users may be transmitting on the

same frequency at the same time, the base station may differentiate them

because the transmitted signals from the users are arriving from different

directions. It is possible to use SDMA in combination with FDMA and

TDMA.

21

The Interleaved Frequency Division Multiple Access (IFDMA)

scheme is a candidate for next generation mobile radio systems described by

T. Frank et al.(2005) based on compassion, repetition and subsequent user

dependent frequency shift of a modulated signal. They insisted that the

multiple accesses are enabled by the assignment of overlapping but mutually

orthogonal subcarriers to each user. Their work also proposed the IFDMA is

derived based on a generalized signal model for pre-coded OFDMA and

robustness properties of IFDMA are investigated by effect of frequency

errors on IFDMA. IFDMA is very effective to frequency offsets. The

IFDMA system is investigated for transmission over an additional white

Gaussian noise (AWGN) channel in an up-link scenario.

The time of arrival based localization has initiated the Line Of Sight

(LOS) for finding the number of Base station (BS) by residual test. Y.T.

Chan et al.(2006) concentrated to identify and localize with the LOS BS

identification by a time history based on hypothesis test. The Residual Test

works on the principal that when all measurements are LOS, when there is

Non line of sight, the normalized residuals defined with two approaches

named as Chi-Square distribution, versus a non-central distribution. The

residuals are the squared differences between the estimates and the true

position. Normalization by their variances gives a unity variance to the

resulting random variables. They also stated that the simulation results for

the chosen geometry and NLOS and measurement noise errors, the RT can

determine the correct number of LOS BS over 90% of the time.

22

Afterwards H.Sari et al.(1997) introduced the concept of OFDMA

with frequency hopping and discussed its performance in the presence of

narrowband interference which characterizes the return channel on cable TV

(CATV) networks. He said in this scheme assigning a particular carrier

frequency, the MAC protocol assigns a periodic sequence to the user which

determines the carrier frequencies to be sequentially used by that user. He

also insisted that frequency hopping and OFDMA becomes a particular case

of multicarrier code-division multiple access (CDMA).

Recent years have witnessed a surge of interest in efficient data

gathering schemes in wireless sensor networks (WSNs). Miao Zhao et

al.(2010) addressed this issue by adopting mobility and space-division

multiple access (SDMA) technique. Their work has been focused on

minimizing the maximum data gathering time among different regions and

refers to it as a mobile data gathering with multiple sensors and SDMA

(MDG-MS) problem. Accordingly, they proposed a region-division and

tour-planning (RDTP) algorithm in which data gathering time is balanced

among different regions. Their results demonstrate that their proposed

algorithms significantly outperform single sensor and non-SDMA schemes.

Hood et al.(2011) described a proof of concept device and method to

estimate the Direction of Arrival (DoA) of a radio signal by a receiver that is

suitable for wireless sensor network (WSN) applications. They show the

error in the measured DoA has a mean smaller than 4° and standard

deviation of smaller than 8°, in both indoor and outdoor environments in

line of sight situations.

23

K. P. Sampoornam et al.(2011) stated that the sensor nodes are

required to operate under remote conditions without a fresh supply of power

to replenish itself. It is a digital multi-carrier modulation scheme that uses a

large number of closely-spaced orthogonal sub-carriers to carry data.

Typically overlap in frequency but are designed not to interfere with each

other as would be the case with traditional FDM(Frequency Division

Multiplexing). Energy conservation becomes the major constraint minimum

energy consumption, several MAC protocols, and analyzed a new MAC

protocol based on OFDM. In ELE-MAC protocol, by employing OFDMA

the energy consumption of the node can be minimized.

In the communication channel performance evaluation of modified

IEEE 802.11 MAC has used for Multi-Channel through the use of a new

channel status indicator. Zygmunt j. Haas et al.(2003) specified the modified

protocol, the RTS/CTS dialogue is exchanged on the common access

control channel and data packets are transmitted on a selected traffic

channel. The evaluation has described based on the multi-channel use and

the results of the throughput specified that the end to end delay for different

network sizes. They also proposed the modification of the protocol that

allow for communication that presented that an algorithm for channel

selection and channel tuning rules. Based on the modified MAC protocol,

throughput increases by 50% to 160% when the multiple channels are used

in the multi-hop and ad hoc network.

24

The traditional MAC (T-MAC) protocols has been designed by Tijs

van Dam et al.(2003) to maximize packet throughput, minimize latency and

provide fairness protocol design for wireless sensor Network. They

introduced T-MAC for an adaptive duty cycle in a novel way for accessing

dynamically ending the active part of time and location. They discussed the

design of the T-MAC and provide a head to head comparison with CSMA

and S-MAC (fixed duty cycle). The T-MAC and S-MAC achieves similar

reductions in energy consumption up to 98 % compared to CSMA (Carrier

Sensor Multiple Access). Their work experimented with comparison of

three protocols CSMA, S-MAC and T-MCA. The results were produced

message length had data payload sizes and did not include the MAC header

4 bytes for CSMA 6 bytes for S-MAC and T-MAC.

Venkatesh Rajendran et al.(2003) described the energy efficiency

and collision free MAC for WSN by traffic adaptive medium access

protocol(TRMA). This method has been reduced the energy in the way of

consumption of energy in unicast, multicast and broadcast transmission with

no collisions. They identified the distributed election scheme is based on

information about the traffic at each node and also described which node

can be transmitted within the time period. Channel has been accessed in

TRAMA for providing energy efficient for maintaining good throughput,

acceptable latencies, and fairness. Energy efficiency has applied by

transmission schedules that avoid collisions of data packets at the receivers

and having nodes, switch to low power radio mode when there has been no

data packets depended for those nodes. The performance of TRAM

evaluated through extensive and synthetic way of sensor scenarios. They

25

insisted that the result of TRAMA both contention based protocol and

Scheduled based protocol are with proper energy savings.

A MAC protocol for ad hoc wireless networks has utilized multiple

channels dynamically to improve performance. Jungmin So et al. (2004)

proposed multiple channels by switching dynamically increased the network

throughput when the network is highly congested. Their work has shown the

result in multiple channel with higher throughput compared to another

multichannel MAC protocol that requires multiple transceivers per host.

They proposed a MAC protocol which enables hosts to dynamically

negotiate channels such that multiple communications can take place in the

same region simultaneously, each in a different channel. The network that

consider is an ad hoc network and does not rely on infrastructure, so there is

no central authority to perform channel management. The main idea is to

divide time into fixed-time intervals using beacons and have a small

window at the start of each interval to indicate traffic and negotiate channels

for use during the interval.

Once MAC and Multiple access technique have been identified, the

localization techniques based on angle of arrival information between

neighbor nodes were identified by RongPeng et al.(2006). The localization

orientation scheme insists that the beacon status has been implemented in

multiple hops away. This scheme is produced the inaccurate angle

measurements and a small number of beacons were passed the good

accuracy of the signal. They also illustrated the localization accuracy for

better coverage of the signal in the multi hop environment. The signal

26

strength has measured for sending and receiving data without interference.

All beacon nodes have Omni directional antennas and also the unknown

nodes are capable of detecting the angles of receiving signals. The scheme

has defined both the position and the orientation by exploring the angle

measurement in all neighboring nodes.

The effectiveness of location based scheme has been implemented for

detecting the unnoticed movement of beacon and producing the localization

accuracy. A probabilistic approach has described that the global localization

within an indoor environment with small amount of infrastructure

requirements. Seshadri.V et al.(2005) stated that global localization is a

flavor of localization in which the device is unaware of its initial position

and has to determine the same from the initial movement of beacons. They

described localization is performed based on the Received Signal

Strength(RSS) as the only sensor reading, which is specified by most off-

the-shelf wireless network interface cards. The measurements of the analysis

have taken by Monte-Carlo sampling for measuring the reading in the

localized environment.

H.L. Miao et al.(2006) introduced the concept of Non line of sight

propagation algorithm Derivations for dealing with propagation error, the

dominant error source in the mobile positioning. They investigated about the

error for finding the signal position in the localized environment. The Root

Mean Square error (RMSE) and maximum likelihood based algorithm have

combined to estimate the mobiles and scatter‟s positions. They found the

procedure by the Cramer-Rao lower bound on the RMSE has derived for the

27

benchmark of the performance comparison. They finally evaluated the

simulation results for producing the performance of the mobile‟s and

scatter‟s positions.

Sheng-Po Kuo et al.(2007) described the Beacon Movement

Detection problem for assigning the unnoticed changes of locations of some

beacons in the system and also stated that the problem about how to monitor

the beacons when an unnoticed events. To improve the localization accuracy

the beacon has been positioned in the particular location and detecting the

unnoticed movement of some beacons. They have found the solution of

Beacon Movement Detection problem not only unnoticed movement of

beacons, but also unnoticed appearance of interference in the sensing area,

which may impact of the localization results.

Chiu et al.(2007) defined the wireless cooperative cellular data

network with a base station and many subscribers in which the subscribers

have the ability to relay information for each other to improve the overall

network performance. They proposed the solution incorporates both user

traffic demand and the physical channel realization in a cross-layer design

that not only allocates power optimally for each user, but also selects the

best relay node and best relay strategy. They also proposed a utility

maximization framework that is capable of selecting the best relay, the best

relay-strategy, and the best power, bandwidth and rate allocation in a

cellular network with relays. By using a dual optimization technique for

OFDMA systems, they shown the difficult joint system optimization

problem can be solved efficiently and globally under a pricing structure.

28

Their proposed resource allocation scheme realizes the cooperative gain of a

relay network by taking into account both physical-layer resource

availability and the application-layer user traffic demands in a cross-layer

approach.

Liang song et al.(2007) developed the wireless sensor network with

mobile sink under a higher density node. A Multiple sensor node can

communicate a single channel for transferring end-end communication.

They are exploiting the tradeoff between retrieval of information probability

and energy consumption. A number of the multiple mode scheduling

algorithms are proposed by them to define optimal and suboptimal

algorithms for studying the cross layer wireless link layer design for Mobile

sink sensor node.

Xiaoyong Chai et al.(2007) aimed to solve the problem by reducing

both the sampling time and the number of locations sampled in constructing

a radio map. They proposed a novel learning algorithm that builds location

estimation systems based on a small fraction of the calibration data that

traditional techniques require and a collection of user traces that can be

cheaply obtained. When the number of sampled locations is reduced, an

interpolation method is developed to effectively patch a radio map.

Extensive experiments show that their proposed methods are effective in

reducing the calibration effort. In particular, unlabeled user traces can be

used to compensate for the effects of reducing the calibration effort and can

even improve the system performance. Consequently, manual effort can be

reduced substantially while a high level of accuracy is still achieved. In the

29

future, they plan to take complex spatial and temporal environment

dynamics into consideration. For example, in building a location-sensing

system, a daytime radio map can be much different from a nighttime one.

Instead of building radio maps for different periods of time, it is interesting

to find a mapping between them and, thus, eliminate the need for tedious

and repeated manual effort. It is also interesting to explore new methods that

can handle small-scale variations better, especially in highly dynamic areas.

Zhi-li Wu et al.(2007) described that location estimation using the

Global System for Mobile Communication(GSM) has an emerging

application that infers the location of the mobile receiver from multiple

signal measurements. They implemented the geometrical model for

identifying the signal positions for solving the estimation problems. They

have communicated a novel synthetic experiment is designed to compare the

performances of different location estimation approaches. They used the

vector regression approach to show the performances in particular about

variations in environmental factors.

A. El-Hoiydi et al.(2007) defined that the power consumption of

medium access control protocols in an infrastructure wireless sensor

network focusing on low downlink traffic. Wise MAC (Wireless Sensor

MAC), a new protocol for the downlink of infrastructure wireless sensor

networks. They analyzed and found the performance of PTIP(Periodic

Terminal Initiated Polling) used in the reversed direction as compared to

common polling protocols. Wise MAC and PTIP are compared with

PSM(Power Save Mode), the power save protocol used in both IEEE 802.11

30

and IEEE 802.15.4 ZigBee Standards. They also proposed the lower delay

of producing the high throughput in the power saving mode. In their

analysis, they focused on high traffic conditions but they focused in the

contrary, on low traffic conditions. Low traffic is expected to be very

common in many applications of ubiquitous computing, where a very long

lifetime is required. It is therefore necessary to understand and minimize the

energy consumption of MAC protocols in low traffic conditions.

Kenneth W. K et al.(2007) described the Particle swarm

optimization(PSO) is employed for positioning with Time Difference of

Arrival(TDoA) measurements in the circumstances of known and unknown

propagation speed. They stated that the optimization criterion is the first

concept to be defined and PSO technique is then employed to search the

global minimum of the cost function. The implementation flow for the

unknown propagation speed case is the same as the known propagation case.

For sufficiently small noise conditions show that the PSO approach provides

accurate source location estimation. Finally they implement this approach

for dealing with highly nonlinear problems.

A machine learning problem has described the signal strengths that

are distributed in different geographical areas based on a sample of

measurements collected at several known locations. T. Roos et al. (2002)

proposed probabilistic framework for solving the location estimation

problem and also they described among all the location estimation method,

which method is validated in real work indoor environment. He also

demonstrated that the feasibility of our approach in a very systematic

31

empirical study in which an average location estimation accuracy of less

than two meters was achieved.

The concept of resource allocation for OFDMA relay networks with

fairness constraints of multiple source nodes, multiple relay nodes and

single destination node was described by Guoqing Li et al.(2006). They

insisted that the optimal source allocation problem with fairness constraint

on relay nodes is formulated as a binary integer programming problem. The

graphical representation of linear optimal distribution problem in a directed

graph pointed out by them and stated that the upper bound of the solution to

evaluate the algorithm performance. The linear problem of OFDMA

technique has implemented for defining the performance for improving the

quality of service. The frequency can be allocated by different users for

allocating the bandwidth in relay networks.

The preemption based resource allocation schemes to support

multiple traffic in an integrated heterogeneous wireless and mobile network

was illustrated by Wei Shen et al.(2007). The traffic has been analyzed in

this criteria whether it is high priority traffic and low priority traffic. They

stated that the resource allocation scheme used in multiple traffic can be

defined under single network. They mainly focused on the two schemes

namely the last accepted call with lower priority is first preempted and in

the second scheme the low priority call that reaches a higher bandwidth

network earliest is preempted first. The result of the system has been shown

that in all the schemes can significantly improve the system performances.

32

The protocol multi-modality enables robustness against any single

protocol failure, due to its assumptions described by Radu Stoleru et

al.(2007). They have shown the 50% decrease in localization error in

comparison with state of art node localization protocol.

Sheng Zhong et al.(2008) described the threshold value for attacking

the malicious nodes. The method which identified a class of localization

algorithms ensure that how much amount of malicious beacons is below the

threshold value. They proposed the results for defining the good accuracy in

the particular location for computing the good efficiency. The polynomial

time is allocated for movement of beacons in the localized environment.

The signal positions are identified with original indented nodes. The

malicious node has been seen in the three dimensional way in the particular

environment.

B.Amutha et al.(2010) presented the localization algorithm used to

define the variation of speed by mobile sink for wireless sensor network. A

mobile sink is the track of the event driven sensor nodes in the path of the

event and this technique conserving energy and time. The mechanism

described the localization algorithm helps to mobile sink for producing the

location sensor efficiently. They stated that the localization mechanism that

proposed here reduces needed power consumption compared to other

schemes. The localization technique is also implemented in Tiny OS

Simulation (TOSSIM). The result defined by them to perform better than

other range based schemes.

33

Cristina Ciochina et al.(2010) demonstrated the OFDMA has

adopted by the WiMAX for mobile WiMAX systems and insisted that

recent concept of 3GPP(Third-Generation Partnership Project) for the

downlink of Long Term Evolution(LTE) systems and single carrier

FDMA(SC-FDMA) has adopted for the downlink LTE. SC-FDMA

combines the all the resources of SC transmission with an OFDMA like

multiple access and attempts to take the strengths of both techniques: Low

Peak-to-Average Power Ratio(PAPR).

Mohamad Haidar et al.(2009) stated that a channel-assignment

algorithm at the Access Points (APs) of a Wireless Local Area Network

(WLAN) is proposed in order to maximize Signal-to-Interference Ratio

(SIR) at the user level. They started with an initial channel assignment

based on minimizing the total interference between APs. Based on this

assignment, they calculated the SIR for each user.

Traditional trust management schemes developed for wired and

wireless ad hoc networks are not well suited for sensor networks due to their

higher consumption of resources such as memory and power described by

Riaz Ahmed Shaikh et al.(2009). They proposed a new lightweight Group

based Trust Management Scheme (GTMS) for wireless sensor networks,

which employs clustering. Our approach reduces the cost of trust evaluation.

Their results shown the demands less memory, energy, and communication

overheads as compared to the current state-of-the-art trust management

schemes and it is more suitable for large-scale sensor networks.

34

Furthermore, GTMS also enables us to detect and prevent malicious, selfish,

and faulty nodes.

The Coverage Control Technology is the one of the basic

technologies of wireless sensor network, and is mainly concerned about how

to prolong the network lifetime on the basis of meeting user‟s perception

demand. The localized area coverage algorithm based on delayed start

scheme is proposed by Xin he, xiaolin gui et al.(2009). It applies time round

mechanism without knowing the network topology in advance and uses

circle intersection coverage evaluation algorithm to ensure fully covered

area and avoid the phenomenon of coverage loopholes

Lamia chaari et al.(2010) defined the methodology of MAC protocol

for defining the performance are related to the medium access mechanism.

An adequate equilibrium between communication improvement and data

processing capabilities must be described. They achieved the concept of low

power operation of WSN. They proposed the energy efficiency for adapting

MAC protocols in order to categorize them and to compare their

performances. They also finally implemented the WSN MAC protocol

under OMNET ++. The intension of the protocol is to minimize the number

of transceiver switches, to make the sleep interval for sensor nodes adaptive

to the amount of data traffic. During its time slot criteria, a node can be

transmitted message which consists of two parts: Control message and a

data unit.

35

Simon J Cockell et al.(2010) introduced an integrated dataset for in

silico drug delivery. Drug development is expensive and prone to failure.

Systematic approaches to drug repositioning are need with an integrated

system biology dataset, developers using the Ondex data integration

platform for the silico discovery of new drug repositioning candidates.

Ondex is a data integration platform for systems biology which addresses

the problem of data integration by repenting many types of data as a

network of interconnected nodes.

Martin H. Skjelvareid et al.(2011) presented a similar focusing

algorithm called multi-layer omega-k (MULOK), which combines PSM and

the ω-k algorithm to perform multilayer imaging more efficiently. The

asymptotic complexity is shown to be lower for MULOK than for PSM, and

this is confirmed by comparing execution times for implementations of both

algorithms. To facilitate the complexity analysis, a detailed description of

algorithm implementation is included, which also serves as a guide for

readers interested in practical implementation.

Mohamad Nikravan et al.(2011) described a Fuzzy Logic System

(FLS) is used as a decision mechanism for next hop node selection. Both

transmission rate and energy are chosen parameters for choosing the next-

hop node in real-time packet transmission. They show the proposed scheme

provides improvement on real-time transmission and energy efficiency

performance, when operating in varying real-time environment.

36

Wireless sensor networks have given rise to many application areas

in health care. It has produced a new field of wireless Body Area Networks

(WBAN). Moshaddique Al Ameen et al.(2011) defined the wearable and

non-wearable sensors both used to track patient activities. They stated that

the security and privacy issues in the various applications. They suggest the

health care sensors are used to solve the issue of tracking system and also

produced the best performance of medical environment. In WBAN concept,

a person wears various devices, but they are used a centralized control

device for data transmission from inside and out of the network. Security

measures such as authentication, firewalls and other checks can be applied

at the controller level to monitor the traffic.

The Mobile sink approach has been used to address the hotspot

problem, but it increases end to end delay which is not acceptable for delay

sensitive application described by Nazir et al.(2011). To solve these two

issues namely, hot-spot problem and delay minimization problem, their

presented QoS aware Energy Efficient Routing (QEER) protocol for

Clustered Wireless Sensor Network.

The dynamic routing layer based data query system is introduced to

handle data query with different route selection mechanism. The route

selection is done with reference to the data query and network density

factors. K. Srujan Raju et al. (2011) designed to handle the data query

operations with dynamic routing layer mechanism in a decentralized

manner. The sensor nodes select the routing protocol with reference to the

data query and network density information.

37

S.P.V.Subba Rao et al. (2011) presented a survey on medium access

control protocols for wireless multimedia networks. A basic overview of

MAC protocol concepts is presented, and a framework is developed for

comparisons. The MAC protocols covered in this article include Random

Access protocols, Contention less protocols, TDMA CDMA, third-

generation WCDMA schemes and Hybrid protocols proposed for wireless

Multimedia Networks. They said the operation of each protocol is

explained, and its advantages and disadvantages are presented.

The cross layer design is used to enhance the performance for uplink

transmission in an OFDM based cellular network with fixed relay stations.

Lei You et al.(2011) proposed to develop a cross layer optimization in two

ways like uplink flows that have different quality of service requirements.

They considered the cross layer trade-off between uplink service rate and

power consumption of sum of transmission power flexibly way of providing

the service rate. The result shown by them to say about OFDMA cellular

network can be fully obtained as reduction in power consumption increase

in service rate and energy savings in the uplink transmission of MS(Mobile

Station). The location of MSs is randomly generated and evenly distributed

over the cell.

Ankita Bansal et al.(2012) described the wireless sensor network

have diverse application domain which includes habitat monitoring and

surveillance. For data aggregation at single source antecedent to transmitting

to any distant user, decentralized maximizing tree is created that preserves

38

energy and maximizes the lifetime of event sources. They proposed a

decentralized lifetime maximizing tree along with hierarchical clustering

that will minimize the energy consumption, delay during data collection and

reduce time complexity.

Ghobadzadeh et al.(2012) shown the uniformly most powerful

(UMP) test is achieved by comparing the MVUE of the unknown parameter

with a threshold. They proved that the UMP unbiased statistic is equal to the

MVUE of an SF. Many problems with multiple unknown parameters, the

UMP test does not exist. In such cases, we show that if one detector between

two detectors has a better receiver operating characteristic (ROC) curve,

then using its decision statistic we can estimate the SF more ε-accurately, in

probability.

A new approach to addressing data consistency in processes

composed of service invocations described by Le Gao et al.(2012). APs

allow for checking of user-defined correctness conditions at different points

during the execution of a business process, along with options for recovery

actions if those conditions are not met, where recovery actions include

rollback, retry, and a recovery technique for hierarchically nested processes

known as cascaded contingency. APs also serve as partial rollback points

from which forward recovery can resume when an error occurs.

A particular attack to the location and neighbor discovery protocols,

carried out by two colluding nodes that set a wormhole to try to deceive an

isolated remote node into believing that it is a neighbor of a set of local

39

nodes. Mariano et al.(2012) defined the framework generally called

Detection of Wormhole Attacks using Range Free (DWARF) methods to

detect the wormhole attack schemes. The first scheme specified that the

procedures in range free techniques and the second scheme have used to

check the validity of estimating position using with range free location.

Once the discovery process finalized, then the performance is compared

with conventional Likelihood Ratio Test (LRT).

Narendrakumar et al.(2012) described the wearable sensor for remote

health care system. The problem of this concept stated by them a patient

have no time to visit the doctor again and again for physical, physiological,

psychological problems. They focused on to solve the problem in the area of

WSN technologies are considered one of the key research areas in computer

science and the healthcare applications industries for improving the quality

of life. The main area of their research work focused on Medical sensors.

The medical sensors have collected the complete data from patients and

transmit it to Intelligent Personal Digital Assistant (IPDA). The

methodology is reduced to minimize the caregivers and help chronically ill

and elderly people live an independent life, besides providing people with

quality care.

Jian Guan et al.(2012) introduced the concept of Energy Balanced

Routing Algorithm based on Mobile Sink(EBRAMS) for wireless sensor

networks. The algorithm defines the Transmitting Coordinate (TC) by

mobile Sink and the sensor nodes. The TC has used for adopting the

technique called the greedy approach. The information about the process is

40

transmitted to mobile sink by LEADER node which has created more

energy. They proposed the EBRAMS with two phases of the process in the

network for transmitting data to mobile sink. One of the methods is

clustering and another method of approach defined the data transmission.

Finally result has been obtained from EBRAMS not only achieve reduction

in energy dissipation and latency but also distribute energy dissipation

evenly throughout the sensors, improve energy efficiency and lengthen

network lifetime compared with other algorithms.

Mohamad Ramazany et al. (2012) addresses the Range-based

localization algorithm has requirements on hardware, thus is expensive to be

implemented in practice. The Range-free localization algorithm reduces the

hardware cost. However, it can only achieve high accuracy in ideal

scenarios. They locate the known nodes by Manual placement (MDVHop)

in various locations for best result. Our algorithm improves the localization

accuracy compared with the previous algorithms, which has been

demonstrated by the simulating the results.

The resource allocation for energy efficient, secure communication in

an orthogonal frequency-division multiple-access (OFDMA) downlink

network is described by Ng D.W.K et al.(2012). They proposed the iterative

resource allocation algorithm not only converges in a small number of

iterations but maximizes the system energy efficiency and guarantees a

nonzero secrecy data rate for the desired users as well.

41

Rajeev Paulus et al.(2012) described a new routing protocol for delay

tolerant wireless sensor network lifetime maximization of delay tolerant

Wireless Sensor Networks through the manipulation of Mobile Sink (MS)

on different trajectories.

Weiqiang Xu al.(2012) proposed the distributed multi-cell

beamforming algorithm converges to an NE point in just a few iterations

with low information exchange overhead. Moreover, it provides significant

performance gains, especially under the strong interference scenario, in

comparison with several existing multi-cell interference mitigation schemes,

such as the distributed interference alignment method.

Attribute reduction is a key studying point of the rough set theory,

and it has been proven that computing minimal reduction of decision tables

is a non-deterministic polynomial (NP)-hard problem described by Ding et

al.(2012). A new cooperative extended attribute reduction algorithm named

Co-PSAR based on improved PSO is proposed them, in which the

cooperative evolutionary strategy with suitable fitness functions is involved

to learn a good hypothesis for accelerating the optimization of searching

minimal attribute reduction.

Di Wu et al.(2013) proposed a set of efficient grid-based channel

allocation and access scheduling algorithms using Latin squares, called as

GAALS, for scalable WSNs with single-radio multi-channel communication

capabilities.

42

Demigha et al.(2013) proposed a novel classification of schemes that

are based on the interaction between the communication subsystem and the

sensing subsystem on a single sensor node. Their interested in collaborative

target tracking instead of single-node tracking.

Wang et al.(2013) proposed the information related to the residual

battery energy of sensor nodes to adaptively adjust the transmission range of

sensor nodes and the relocating scheme for the sink. They also specified the

theoretical and numerical analyze are given to show that the energy-aware

sink relocation (EASR) method can extend the network lifetime of the WSN

significantly.

Shah et al (2013) proposed framework exploits the emerging

cognitive radio technology to mitigate the noise and congested spectrum

bands, yielding reliable and high capacity links for wireless communication

in smart grids. To meet the QoS requirements of diverse smart grid

applications, they differentiate the traffic flows into different priority classes

according to their QoS needs and maintain three dimensional service queues

attributing delay, bandwidth and reliability of data.

Soochang Park et al.(2013) described on delivery-guaranteed and

effective data dissemination for mobile sink groups in wireless sensor

networks. A mobile sink group denotes a set of tightly coupled mobile sinks

for team collaborations such as a team of firefighters and a group of

soldiers. They randomly move in personal spaces as well as collectively

move together as a single entity. Since a group is still moving to take a

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decision of each circle, they may cause asynchrony between circles and

actual group positions. The transmission can be reached safely with a set of

energy efficiency. They proposed a novel data dissemination protocol using

motion properties of a mobile sink group slowly varying and stream like

movement. They proved the concept of mobile sink for giving better

performance than previous protocols with respect to energy efficiency for

both are signaling overhead and data forwarding.

N. Javaid et al.(2013) introduced the new protocol Square Routing

Protocol with MS(SRP-MS) for improving the delay tolerant WSN. The

main aim of the concept stated by them are Stable Election Protocol (SEP)

removing its clustering mechanism and introducing MS in the field. The

enhancement of the method defined the data collection in WSNs by MS in

clusterless network and introduced Mobile network. SRP has used to find

the shortest path between sensors and sink. When the sink is moving on the

predefined trajectory, the sensor nodes in the field and gathering data, only

sensors in the sensing range send their data to the sink. Other nodes are in

sleep mode until the sink is arrived.

Media Aminian et al.(2013) introduced a Hospital healthcare

monitoring system using wireless sensor networks. A monitoring system has

the capability of monitor physiological parameters from multiple patient

bodies. They proposed a system of coordinating nodes has attached nodes

has attached to patient body to collect all the signals from the wireless

sensor and sends them to the base station. The attached sensors on patient‟s

body from a Wireless Body Sensor Network (WBSN) and it will be

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produced in the heart rate, blood pressure and so on. This system can detect

the abnormal conditions, issue an alarm to the patient and send SMS/E-mail

to the physician. The result has defined by them in multi patient architecture

for hospital healthcare and compared it with the other existing networks

based on multi-hop relay node in terms of coverage, energy consumption

and speed.

Lin Mei et al.(2013) provided a reference for the future stockpiling of

drugs and developing vaccines for treatment of emerging infectious diseases

by summarizing the status of drug stockpiling, vaccine development, and

related policies during three major outbreaks of avian influenza among

humans (H5N1 in 2003, H1N1 in 2009, and H7N9 in 2013). They proposed

that the security can be used in medical healthcare application, especially in

detecting human heartbeat. Drug stockpiling, vaccine development, and

related policies to treat influenza outbreaks have improved markedly. The

response was faster and more effective in terms of stockpiling of antivirals

and vaccine development. These improvements also suggest advances in

related policy planning. These trends also foreshadow better prospects for

prevention and control of emerging infectious diseases. However, the

rationality of drug stockpiling and international cooperation still need to be

enhanced.

Abhishek Rout et al.(2013) proposed a new security technique

(wavelet) in healthcare applications without considering security makes

patient privacy vulnerable based on an advanced Wireless Sensor Network

(WSN) due to the required level of trustworthiness and the need to ensure

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the privacy and security of medical data. The monitoring and acquisition of

patients‟ physiological information are quite Crucial for the further

treatment. Many patients can benefit from continuous monitoring as a part

of a diagnostic procedure, optimal maintenance of a chronic condition or

during supervised recovery from an acute event or surgical procedure. They

looked into the future, the tussle between trustworthiness and privacy and

the ability to deploy large-scale systems that meet the application‟s

requirements, even when deployed and operated in unsupervised

environments is going to determine the extent that wireless sensor networks

will be successfully integrated in healthcare practice and research.

Leinonen et al.(2013) found a new algorithm to converge

significantly faster as compared to the state of the art methods based on the

dual decomposition. Additionally, their algorithm is appealing for practical

implementation due to its low local communication overhead, robust

operation in slightly changing channel conditions and scalability to large

networks.

Masmoudi et al.(2013) presented a new implementation of the

maximum likelihood criterion for the estimation of the time delays in a

multipath environment and then extend it to the estimation of the TDoA

when the transmitted signal is unknown. They carried out the comparisons

with some other methods such as the EM algorithm, MUSIC and accelerated

random search (ARS) demonstrates the superiority of the proposed IS-based

multipath delay estimator in terms of estimation performance and

complexity.

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Soomin Ko et al.(2013) proposed a new feedback scheme called

mode selection-based feedback by scheduling probability prediction (SPP-

MF) for channel state feedback in the OFDMA downlink system. They

design the scheme such that it determines the more desirable feedback mode

among selective feedback by scheduling probability prediction (SPP-SF)

mode and bitmap feedback by scheduling probability prediction (SPP-BF)

mode, by calculating and comparing the throughputs of the two modes.

Optimization algorithms have proven to be good candidates for

quality of position estimation defined by Mansoor-ul-Haque et al.(2013).

Flip ambiguity is one of the major challenges in such techniques. Their

constraints are proposed to overcome this problem. Particle Swarm

Optimization (PSO) in conjunction with the proposed constraints is used

iteratively in distributed manners to localize blind nodes in the WSN. Their

Simulation results show that the proposed technique overcomes the problem

of flip ambiguity and is resource efficient as well.

YoungSang et al.(2013) proposed an algorithm for maximizing the

lifetime of a wireless sensor network when there is a mobile sink and the

underlying application can tolerate some amount of delay in delivering the

data to the sink. Their algorithm is distributed, and in addition, mostly uses

local information. Such an algorithm can be implemented by parallel and/or

distributed execution and the overhead of message passing is low.

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The key concept in virtual backbone scheduling is to minimize the

energy consumption and more throughputs concentrated by Umesh B.N et

al.(2013). To achieve QOS, fault tolerance of these backbone nodes in Multi

hop Networks requires stable links. They proposed an energy efficient

routing for Virtual Back Bone Nodes (VBS) in which it maximizes the node

life and turns off its radio when they are in sleep mode, in order to consume

less energy. A concept of restricted back bone neighborhood routing is

proposed, which assures the efficient routing with minimum energy

consumption of nodes and they also implemented the critical transmission

radius for Backbone nodes.

Hua-Jie Shao et al. (2014) developed a set of efficient closed-form

AOA based self-localization algorithms using auxiliary variables based

methods. First, we formulate the self-localization problem as a linear least

squares problem using auxiliary variables and they developed a novel

BCAVPLE based weighted instrumental variable (BCAVPLE-WIV)

estimator to achieve asymptotically unbiased estimation of locations and

orientations of unknown nodes based on prior knowledge of the AOA noise

variance.

To improve the positioning accuracy, this paper puts forward an

improved weighted centroid algorithm, then self-corrected defined by Zhao

ju-Min et al.(2014) . They take any four beacon nodes to improve the node

localization accuracy, retaining the simplicity of the algorithm and saving

nodes energy. These four beacon nodes compose a quadrangle, which is

then divided into two triangles to seek centroids and get their average

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values. Thereafter, they we measure each beacon node and empower the

values, then use the centroid localization algorithm again to locate object

nodes. Their simulations show that the algorithm effectively improves the

positioning accuracy of the unknown nodes.

A novel resource allocation for visible light based WSN discussed by

Saha et al.(2014). They proposed joint power allocation and bandwidth

allocation for downlink transmission. Then their proposed admission control

to guarantee quality of service (QoS) in order to maintain service

requirement. Their simulation result has shown the satisfactory performance

improvement.

The performance analysis of chunk-based resource allocation is

studied in the multi-cell OFDMA environment demonstrated by Huiling

Zhu et al.(2014). They evaluated how spectral efficiency performance is

affected by system parameters, including the radius ratio of the central area

of the whole cell, transmits signal to noise ratio (SNR), number of users,

number of subcarriers per chunk, and coherence bandwidth. The numerical

results show that there exists an optimal radius ratio to achieve the highest

spectral efficiency in the proposed research. The optimal radius ratio is

about 0.7, which is almost irrespective of the SNR, number of users, and

number of subcarriers per chunk.