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.