In this paper, we propose a new simple relaying strategy based on bit-interleaved convolutionally coded starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay. Here we are using the higher order modulation for improving relay communication, and also employ the accurate relay technique. Moreover, we show that the proposed approach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguity, by analyzing our proposed method in terms of asymptotic pairwise error probability (PEP), Furthermore, the effectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal power. And also implement the PEP in MIMO systems for improving the powerefficiency. All the theoretical results agree with those obtained by computer simulations.
Improving Power Efficiency in Cooperative Diversity and Mimo Systems by Using...IJERA Editor
In this paper, we propose a new simple relayingstrategy based on bit-interleaved convolutionally coded starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay.here we are using the higher order modulation for improving relay communication and also employ the accurate relay technique.Moreover, we show that the proposedapproach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguityBy analyzing our proposed method in terms of asymptotic pairwise error probability(PEP),Furthermore, theeffectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal power.and also implement the PEP in MIMO systems for improving the power efficiency.All the theoretical results agree with those obtained by computer simulations.
This document summarizes a research paper that proposes an energy and bandwidth constrained routing technique for mobile ad hoc networks (MANETs). It presents an available bandwidth measurement algorithm that estimates available bandwidth more accurately by considering node capacity, link utilization, idle time synchronization, collision probability, and overhead from backoff mechanisms. It also proposes a probability-based overhearing method to reduce energy consumption from overhearing without affecting route quality. The techniques are evaluated using NS2 simulations to analyze network performance in terms of quality of service parameters.
Multicast Routing Protocol with Group-Level Congestion Prediction and Perman...IOSR Journals
This document proposes a cross-layered model for congestion prediction and management in mobile ad hoc networks that aims to efficiently distribute network resources. The model incorporates two algorithms: Group-level Congestion Prediction (GCP) that predicts congestion levels at relay nodes with high accuracy, and Group-level Egress Permanence (GEP) that works sequentially with GCP for congestion detection and management. The document discusses related work on multicast routing protocols and energy-efficient multicasting. It then describes the proposed congestion control mechanism under constrained energy utilization and outlines the proposed model with relevant notations before focusing on the GCP and GEP algorithms.
Improving thrpoughput and energy efficiency by pctar protocol in wirelessIaetsd Iaetsd
The document discusses a proposed Prioritized Congestion and Traffic Aware Routing (PCTAR) protocol for wireless sensor networks. PCTAR aims to improve throughput and energy efficiency. It does so by dynamically discovering routing zones using hybrid potential fields that consider both depth (distance to sink) and queue length, as well as data priority. Simulation results showed PCTAR improved overall throughput by 70% compared to the TADR protocol. PCTAR is suitable for applications in healthcare monitoring and military domains by prioritizing data delivery and reducing congestion.
This document summarizes a research paper that proposes a new cooperative channel load aware VoIP routing topology for 802.11 WLAN networks. It introduces the concept of cooperative channel transmitting technology for 802.11 WLAN networks and discusses some of the challenges in providing quality of service guarantees. It then presents a linear programming model and scheduling algorithm to implement cooperative channel transmissions while considering queue status and transitive node relationships to maximize throughput. Simulation results show that the proposed scheduling algorithm improves throughput and fairness compared to alternatives.
Iaetsd increasing network life span of manet by usingIaetsd Iaetsd
This document proposes algorithms to maximize network lifetime in wireless sensor networks using cooperative MAC protocols. It formulates the problems of minimizing transmission power and maximizing network lifetime as cross-layer optimization problems considering routing, relay selection, and power allocation. Distributed algorithms are presented that solve these problems for both direct transmission and cooperative transmission modes. The algorithms select routes and relay nodes to minimize power consumption or equalize node lifetimes while meeting requirements for transmission success probability and rate.
PERFORMANCE IMPROVEMENT OF NONREGENERATIVE COOPERATIVE RELAY NETWORKS WITH OP...ijwmn
This paper analyzes the performance of cooperative amplify-and-forward (CAF) relay networks that employ both optimal power allocation among nodes based on relay position and adaptive M-QAM/M-PSK modulation in generalized fading environments. The paper develops a unified analytical framework using marginal moment generating functions to derive expressions for average bit error rate, mean achievable spectral efficiency, and outage probability over a range of fading distributions. It applies this framework to analyze CAF relay networks with adaptive modulation over Rice fading channels. The paper also employs an approximate moment generating function to further simplify computation complexity. Finally, it applies the framework to analyze the impact of optimal power allocation based on relay position.
This document summarizes a research paper that proposes using a hybrid of simulated annealing algorithm and fuzzy rule base system (SA-FRBS) for adaptive coding, modulation, and power allocation in orthogonal frequency-division multiplexing (OFDM) systems. The paper first discusses related work on using evolutionary algorithms like genetic algorithms for adaptive resource allocation in OFDM. It then describes the system model and analyzes the performance of different modulation and coding schemes. Next, it formulates the rate optimization problem and describes the design of the FRBS for selecting the optimal modulation-coding pairs. Finally, it compares the performance of the proposed SA-FRBS approach through simulations.
Improving Power Efficiency in Cooperative Diversity and Mimo Systems by Using...IJERA Editor
In this paper, we propose a new simple relayingstrategy based on bit-interleaved convolutionally coded starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay.here we are using the higher order modulation for improving relay communication and also employ the accurate relay technique.Moreover, we show that the proposedapproach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguityBy analyzing our proposed method in terms of asymptotic pairwise error probability(PEP),Furthermore, theeffectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal power.and also implement the PEP in MIMO systems for improving the power efficiency.All the theoretical results agree with those obtained by computer simulations.
This document summarizes a research paper that proposes an energy and bandwidth constrained routing technique for mobile ad hoc networks (MANETs). It presents an available bandwidth measurement algorithm that estimates available bandwidth more accurately by considering node capacity, link utilization, idle time synchronization, collision probability, and overhead from backoff mechanisms. It also proposes a probability-based overhearing method to reduce energy consumption from overhearing without affecting route quality. The techniques are evaluated using NS2 simulations to analyze network performance in terms of quality of service parameters.
Multicast Routing Protocol with Group-Level Congestion Prediction and Perman...IOSR Journals
This document proposes a cross-layered model for congestion prediction and management in mobile ad hoc networks that aims to efficiently distribute network resources. The model incorporates two algorithms: Group-level Congestion Prediction (GCP) that predicts congestion levels at relay nodes with high accuracy, and Group-level Egress Permanence (GEP) that works sequentially with GCP for congestion detection and management. The document discusses related work on multicast routing protocols and energy-efficient multicasting. It then describes the proposed congestion control mechanism under constrained energy utilization and outlines the proposed model with relevant notations before focusing on the GCP and GEP algorithms.
Improving thrpoughput and energy efficiency by pctar protocol in wirelessIaetsd Iaetsd
The document discusses a proposed Prioritized Congestion and Traffic Aware Routing (PCTAR) protocol for wireless sensor networks. PCTAR aims to improve throughput and energy efficiency. It does so by dynamically discovering routing zones using hybrid potential fields that consider both depth (distance to sink) and queue length, as well as data priority. Simulation results showed PCTAR improved overall throughput by 70% compared to the TADR protocol. PCTAR is suitable for applications in healthcare monitoring and military domains by prioritizing data delivery and reducing congestion.
This document summarizes a research paper that proposes a new cooperative channel load aware VoIP routing topology for 802.11 WLAN networks. It introduces the concept of cooperative channel transmitting technology for 802.11 WLAN networks and discusses some of the challenges in providing quality of service guarantees. It then presents a linear programming model and scheduling algorithm to implement cooperative channel transmissions while considering queue status and transitive node relationships to maximize throughput. Simulation results show that the proposed scheduling algorithm improves throughput and fairness compared to alternatives.
Iaetsd increasing network life span of manet by usingIaetsd Iaetsd
This document proposes algorithms to maximize network lifetime in wireless sensor networks using cooperative MAC protocols. It formulates the problems of minimizing transmission power and maximizing network lifetime as cross-layer optimization problems considering routing, relay selection, and power allocation. Distributed algorithms are presented that solve these problems for both direct transmission and cooperative transmission modes. The algorithms select routes and relay nodes to minimize power consumption or equalize node lifetimes while meeting requirements for transmission success probability and rate.
PERFORMANCE IMPROVEMENT OF NONREGENERATIVE COOPERATIVE RELAY NETWORKS WITH OP...ijwmn
This paper analyzes the performance of cooperative amplify-and-forward (CAF) relay networks that employ both optimal power allocation among nodes based on relay position and adaptive M-QAM/M-PSK modulation in generalized fading environments. The paper develops a unified analytical framework using marginal moment generating functions to derive expressions for average bit error rate, mean achievable spectral efficiency, and outage probability over a range of fading distributions. It applies this framework to analyze CAF relay networks with adaptive modulation over Rice fading channels. The paper also employs an approximate moment generating function to further simplify computation complexity. Finally, it applies the framework to analyze the impact of optimal power allocation based on relay position.
This document summarizes a research paper that proposes using a hybrid of simulated annealing algorithm and fuzzy rule base system (SA-FRBS) for adaptive coding, modulation, and power allocation in orthogonal frequency-division multiplexing (OFDM) systems. The paper first discusses related work on using evolutionary algorithms like genetic algorithms for adaptive resource allocation in OFDM. It then describes the system model and analyzes the performance of different modulation and coding schemes. Next, it formulates the rate optimization problem and describes the design of the FRBS for selecting the optimal modulation-coding pairs. Finally, it compares the performance of the proposed SA-FRBS approach through simulations.
This document presents an intelligent link adaptation scheme for OFDM systems that adapts coding, modulation, and power allocation to maximize throughput. It uses a fuzzy rule-based system to select the optimal modulation and coding scheme based on channel state information and quality of service requirements. It then uses a differential evolution algorithm to find the optimal power vector to transmit over OFDM subcarriers while satisfying total power and bit error rate constraints. The proposed scheme is shown through simulations to outperform conventional fixed schemes and adaptive schemes that only optimize a subset of parameters. Product codes and QAM are used as the coding and modulation schemes, respectively.
MESSAGE ROUTING IN WIRELESS AND MOBILE NETWORKS USING TDMA TECHNOLOGYijwmn
In an era where communication has a most important role in modern societies, designing efficient
algorithms for data transmission is of the outmost importance. TDMA is a technology used in many
communication systems such as satellite, cell phone as well as other wireless or mobile networks. Most 2G
cellular systems as well as some 3G are TDMA based. In order to transmit data in such systems we need
to cluster them in packages. To achieve a faster transmission we are allowed to preempt the transmission of
any packet in order to resume at a later time. Preemption can be used to reduce idleness of some stations.
Such preemptions though come with a reconfiguration cost in order to setup for the next transmission. In
this paper we propose two algorithms which yield improved transmission scheduling. These two algorithms
we call MGA and IMGA (Improved MGA). We have proven an approximation ratio for MGA and ran
experiments to establish that it works even better in practice. In order to conclude that MGA will be a very
helpful tool in constructing an improved schedule for packet routing using preemtion with a setup cost, we
compare its results to two other efficient algorithms designed by researchers in the past: A-PBS(d+1) and
GWA. To establish the efficiency of IMGA we ran experiments in comparison to MGA as well as APBS(d+1)
and GWA. IMGA has proven to produce the most efficient schedule on all counts.
An enhanced available bandwidth estimation technique for an end to end networ...redpel dot com
The document describes an enhanced technique for estimating available bandwidth (ABW) of an end-to-end network path. It proposes a unique probing scheme using a probing train structure with a high-density region to detect the turning point more accurately. It also includes a rate adjustment algorithm and a modified excursion detection algorithm to estimate ABW more accurately and less intrusively. Experimental results using an Android device over a 4G/LTE network and a testbed show the technique outperforms other state-of-the-art methods in terms of accuracy, intrusiveness, and convergence time.
Qo s oriented distributed routing protocols : anna university 2nd review pptAAKASH S
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
In this paper introduce the QoS-Oriented Distributed routing protocol(QOD)
This QOD protocol makes five contributions:
QoS-guaranteed neighbor selection algorithm
Distributed packet scheduling algorithm
Mobility-based segment resizing algorithm
Soft-deadline based forwarding scheduling algorithm
Data redundancy elimination based transmission
EFFICIENT REBROADCASTING USING TRUSTWORTHINESS OF NODE WITH NEIGHBOUR KNOWLED...ijiert bestjournal
Mobile Ad hoc network is an infrastructure less communication network with limited resources. To maintain virtual
infrastructure for communication broadcasting mechanisms is used. Due to lack of energy efficiency in Mobile Ad
hoc network, there is a need to develop an efficient broadcasting model which enhances energy efficiency. Also
nodes with malicious behaviour cause an internal threat that disobeys the standard and degrades the performance of
routing protocols. This paper introduced an enhanced rebroadcasting algorithm, where rebroadcasting decision for
next hop is immediate or delayed on the basis of trust value and energy level of particular node. This approach helps
to decrease number of rebroadcast, energy consumption and also enhances security. The decision is made with trust
value associated with node, their remaining energy and total number of uncovered nodes.
An Improved Energy Efficient Wireless Sensor Networks Through Clustering In C...Editor IJCATR
One of the major reason for performance degradation in Wireless sensor network is the overhead due to control packet and packet delivery degradation. Clustering in cross layer network operation is an efficient way manage control packet overhead and which ultimately improve the lifetime of a network. All these overheads are crucial in a scalable networks. But the clustering always suffer from the cluster head failure which need to be solved effectively in a large network. As the focus is to improve the average lifetime of sensor network the cluster head is selected based on the battery life of nodes. The cross-layer operation model optimize the overheads in multiple layer and ultimately the use of clustering will reduce the major overheads identified and their by the energy consumption and throughput of wireless sensor network is improved. The proposed model operates on two layers of network ie., Network Layer and Transport Layer and Clustering is applied in the network layer . The simulation result shows that the integration of two layers reduces the energy consumption and increases the throughput of the wireless sensor networks.
Modified q aware scheduling algorithm for improved fairness in 802.16 j networksIJCNCJournal
Deployment of Multi-hop Relays in WiMax based Cellu
lar Networks is considered as a cost effective
solution to increase the Coverage area of Base Stat
ion and also to improve the Network Capacity with h
igh
quality short links. Scheduling became a challengin
g task in these Multi-hop Relay Wireless Cellular
Networks of IEEE 802.16j standard. H. Chen, X. Xie
and H. Wu proposed a Q-aware Scheduling
Algorithm in which back-pressure flow control mecha
nism is used to reflect current Q size of the Relay
s
and considered high back-pressure links to include
in Concurrent Transmission Scenarios, to maximize t
he
throughput. This focus on high back-pressure links,
leads to starvation of Mobile Stations having low
back-
pressure links, resulting unfairness in some cases.
To remedy this situation, a Fair Link Inclusion (F
LI)
mechanism is applied in Greedy Algorithm of Q-aware
Scheduling Algorithm. Simulation results show that
Modified Q-aware Scheduling Algorithm with FLI mech
anism has reasonable improvement in fairness and
maintaining steady throughput when compared with ex
isting algorithms.
Civilizing the Network Lifespan of Manets Through Cooperative Mac Protocol Me...IRJET Journal
1) The document discusses a proposed cooperative medium access control (CMAC) protocol for mobile ad-hoc networks (MANETs) that aims to improve energy efficiency and extend network lifetime.
2) Existing CMAC protocols focus on throughput enhancement but fail to adequately consider energy efficiency. The proposed DEL-CMAC protocol aims to extend network lifetime by accounting for energy consumption at both transmitters and receivers.
3) Cooperative communication techniques that employ relay nodes can provide spatial diversity gains to reduce transmission power needs. However, the overhead of cooperation may outweigh these gains, so an efficient CMAC protocol is required to manage medium access for cooperative transmissions.
The document proposes an Enhanced Heuristic Function based Energy Aware (EHF-EA) routing protocol for wireless sensor networks. EHF-EA aims to extend network lifetime and improve link quality by using a heuristic function to find optimal routes while considering longevity factor, link quality, and bandwidth. It constructs a network of 50 mobile homogeneous sensor nodes in clusters. EHF-EA computes heuristic and cost values to determine the best next hop to the destination, aiming to efficiently transfer data and conserve energy. Simulation results show EHF-EA achieves a 93.85% packet delivery ratio while reducing bandwidth and number of hops compared to other protocols.
Routing in Cognitive Radio Networks - A SurveyIJERA Editor
Cognitive Radio Networks (CRNs) have been emerged as a revolutionary solution to migrate the spectrum
scarcity problem in wireless networks. Due to increasing demand for additional spectrum resources, CRNs have
been receiving significant research to solve issues related with spectrum underutilization. This technology
brings efficient spectrum usage and effective interference avoidance, and also brings new challenges to routing
in multi-hop Cognitive Radio Networks. In CRN, unlicensed users or secondary users are able to use
underutilized licensed channels, but they have to leave the channel if any interference is caused to the primary or
licensed users. So CR technology allows sharing of licensed spectrum band in opportunistic and non-interfering
manner. Different routing protocols have been proposed recently based on different design goals under different
assumptions.
Performance Analysis of Enhanced Opportunistic Minimum Cost Routingin Mobile ...IJERA Editor
Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network with
infrastructure less environment to establish a data transmission between nodes within the network. A routing
protocol is used to discover routes between nodes. In this paper, we study the three existing routing protocols
namely AODV, DSDV and DSR to analyze theirperformance based on set of parameters.AODV and DSR
deliver almost all the packets compared to DSDV. Hence we try to modify the AODVprotocol and use in the
cooperative transmission.
In this paper, we study the cooperative transmission at the network layer and cooperative diversity at the
physical layer as a joint optimization of the transmission power in a Mobile Ad-Hoc Network (MANET) with
static channel. However due to variable wireless channels static routing is suboptimal. Proposed protocol
proactively selects forwarding nodes that work cooperatively forwarding the packet towards the destination.
Cooperative transmission side diversity helps in reducing interference. Diversity can be achieved at the physical
layer by coordinating the multiple nodes. Nodes are equipped with Omni-directional antenna and take the
advantages of transmission side diversity to achieve energy saving, under the assumption that channel gains are
available at the transmitters.
The proposed Opportunistic Minimum Cost Cooperative Transmission Shortest Path (OMCTSP) algorithms
select the best optimum route with minimum cost in terms of energy, number of hops, available bandwidth, link
quality (SNR) and outage probability. As the network becomes larger, finding optimal routes becomes
computationally intractable as the complexity of the dynamic programming (DP) approach increases as o (22n)
where n is the number of nodes in the networks. Hence we develop two suboptimal algorithms have complexity
of o (n2) perform as same as optimal algorithm. Also developthe Opportunistic Cooperative Routing in MANET
(O_CORMAN), which is a network layer opportunistic routing scheme for mobile ad hoc networks. Nodes in
the network use the components proactive routing protocol, forwarder list update and local re-transmission. We
evaluate the performance using NS 2.32 simulator there is significant performance improvement with respect to
energy, throughput packet delivery, and delay compared with Modified AODV (OMCTSP).
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
A novel routing technique for mobile ad hoc networks (manet)ijngnjournal
Actual network size depends on the application and the protocols developed for the routing for this kind of
networks should be scalable and efficient. Each routing protocol should support small as well as large
scale networks very efficiently. As the number of node increase, it increases the management functionality
of the network. Graph theoretic approach traditionally was applied to networks where nodes are static or
fixed. In this paper, we have applied the graph theoretic routing to MANET where nodes are mobile. Here,
we designed all identical nodes in the cluster except the cluster head and this criterion reduces the
management burden on the network. Each cluster supports a few nodes with a cluster head. The intracluster
connectivity amongst the nodes within the cluster is supported by multi-hop connectivity to ensure
handling mobility in such a way that no service disruption can occur. The inter-cluster connectivity is also
achieved by multi-hop connectivity. However, for inter-cluster communications, only cluster heads are
connected. This paper demonstrates graph theoretic approach produces an optimum multi-hop connectivity
path based on cumulative minimum degree that minimizes the contention and scheduling delay end-toend.
It is applied to both intra-cluster communications as well as inter-cluster communications. The
performance shows that having a multi-hop connectivity for intra-cluster communications is more power
efficient compared to broadcast of information with maximum power coverage. We also showed the total
number of required intermediate nodes in the transmission from source to destination. However, dynamic
behavior of the nodes requires greater understanding of the node degree and mobility at each instance of
time in order to maintain end-to-end QoS for multi-service provisioning. Our simulation results show that
the proposed graph theoretic routing approach will reduce the overall delay and improves the physical
layer data frame transmission.
This document compares the performance of three routing protocols for mobile ad hoc networks (MANETs): AOMDV, AOMDV with location information using the DREAM protocol, and AOMDV with energy information. AOMDV is a multipath routing protocol that finds multiple disjoint paths between nodes. AOMDV with DREAM uses location information to route packets more efficiently. AOMDV with energy information selects paths based on the residual energy of nodes to improve energy efficiency and network lifetime. The document provides an overview of these three protocols and reviews previous work comparing their performance based on metrics like energy consumption, packet delivery ratio, and throughput.
Hybrid networks is integrate MANETs and infrastructure wireless networks
It have proven to be a better network structure for the next generation networks
It can act Base station and Ad hoc according to the environment conditions
The widespread use of mobile devices the increasing demand for mobile multimedia streaming services
The future of real time need of high Quality of Service (QoS) support in wireless and mobile networking environments
The QoS support reduces end to end transmission delay and enhances throughput to guarantee the seamless communication between mobile devices and wireless infrastructures
Specifically, infrastructure networks improve the scalability of MANETs, while MANETs automatically establish self-organizing networks, extending the coverage of the infrastructure networks
This document summarizes a research project on developing an energy efficient routing protocol for mobile ad hoc networks. It discusses how current routing protocols do not consider energy efficiency. The proposed Energy Efficient Source Routing Protocol (EESR) aims to reduce energy consumption, balance energy usage across nodes, and increase network lifetime. EESR selects routes based on a cost metric that considers transmission power, distance between nodes, and remaining battery capacity. Simulation results show EESR increases remaining power levels, lowers variations in power levels, and improves packet delivery rate compared to the Dynamic Source Routing protocol.
This document describes an online tutoring service for digital signal processing homework and projects. It provides tutors experienced in digital signal processing to help with assignments and long-term projects. The document also includes sample MATLAB code for a GUI that implements quadrature amplitude modulation (QAM) with functions for various toggle buttons that create figures or exit the program.
1) The document describes an experiment on Quadrature Amplitude Modulation (QAM).
2) QAM is introduced as a digital modulation technique that modulates two analog/digital messages by changing the amplitude of two carrier waves that are out of phase.
3) Matlab code is provided to simulate QAM modulation and demodulation of signals with different frequencies to demonstrate how QAM works.
Performance Evaluation of Different QAM Techniques Using Matlab/Simulink full...vnktrjr
This document discusses the performance evaluation of different quadrature amplitude modulation (QAM) techniques using MATLAB/Simulink. It aims to develop a Simulink model to simulate various QAM modulation and demodulation schemes at bit rates ranging from 8 to 256 bits. The model transmits a randomly generated signal through an additive white Gaussian noise channel. It then measures the bit error rate versus the ratio of bit energy to noise power spectral density to evaluate each QAM technique's performance. The document explains QAM modulation mathematically and discusses signal constellations for different QAM orders. It also outlines the methodology and implementation of the Simulink model, including the use of a random integer generator and additive white Gaussian noise channel.
The document provides a summary of AIESEC's quarterly assessment meeting covering various areas including exchange development, marketing, business development, external relations, communications, expansions, talent development, information management, finance, and human resources.
Key areas of concern across departments included low RMR performance, lack of sustainable processes, failure to meet targets, inadequate partner engagement, and lack of standardized operations and accountability. Financial obligations were also noted as a liability. Overall, the meeting assessed performance in the first quarter and identified weaknesses to address in order to improve outcomes going forward.
The document describes a digital Quadrature Amplitude Modulation (QAM) transmitter. It discusses how QAM digitally modulates information onto the amplitudes of a sine and cosine wave, or equivalently onto the amplitude and phase of a single sinusoid. The transmitter uses pulse shaping filters and a Hilbert transformer to generate the in-phase and quadrature signals from the digital bit stream before upconverting and transmitting. Performance analysis methods for QAM are also presented to calculate decision regions and probabilities of correct detection.
This document presents an intelligent link adaptation scheme for OFDM systems that adapts coding, modulation, and power allocation to maximize throughput. It uses a fuzzy rule-based system to select the optimal modulation and coding scheme based on channel state information and quality of service requirements. It then uses a differential evolution algorithm to find the optimal power vector to transmit over OFDM subcarriers while satisfying total power and bit error rate constraints. The proposed scheme is shown through simulations to outperform conventional fixed schemes and adaptive schemes that only optimize a subset of parameters. Product codes and QAM are used as the coding and modulation schemes, respectively.
MESSAGE ROUTING IN WIRELESS AND MOBILE NETWORKS USING TDMA TECHNOLOGYijwmn
In an era where communication has a most important role in modern societies, designing efficient
algorithms for data transmission is of the outmost importance. TDMA is a technology used in many
communication systems such as satellite, cell phone as well as other wireless or mobile networks. Most 2G
cellular systems as well as some 3G are TDMA based. In order to transmit data in such systems we need
to cluster them in packages. To achieve a faster transmission we are allowed to preempt the transmission of
any packet in order to resume at a later time. Preemption can be used to reduce idleness of some stations.
Such preemptions though come with a reconfiguration cost in order to setup for the next transmission. In
this paper we propose two algorithms which yield improved transmission scheduling. These two algorithms
we call MGA and IMGA (Improved MGA). We have proven an approximation ratio for MGA and ran
experiments to establish that it works even better in practice. In order to conclude that MGA will be a very
helpful tool in constructing an improved schedule for packet routing using preemtion with a setup cost, we
compare its results to two other efficient algorithms designed by researchers in the past: A-PBS(d+1) and
GWA. To establish the efficiency of IMGA we ran experiments in comparison to MGA as well as APBS(d+1)
and GWA. IMGA has proven to produce the most efficient schedule on all counts.
An enhanced available bandwidth estimation technique for an end to end networ...redpel dot com
The document describes an enhanced technique for estimating available bandwidth (ABW) of an end-to-end network path. It proposes a unique probing scheme using a probing train structure with a high-density region to detect the turning point more accurately. It also includes a rate adjustment algorithm and a modified excursion detection algorithm to estimate ABW more accurately and less intrusively. Experimental results using an Android device over a 4G/LTE network and a testbed show the technique outperforms other state-of-the-art methods in terms of accuracy, intrusiveness, and convergence time.
Qo s oriented distributed routing protocols : anna university 2nd review pptAAKASH S
To find a QoS path between source and destination, Which satisfies
The QoS requirements for each admitted connection and
Optimizes the use of network resources
Quality encompasses the data loss, latency, jitter, efficient use of network resources,..
QoS mechanisms for unfairness: managing queuing behavior, shaping traffic, control admission, routing, …
Usually, a hybrid network has widespread base stations
The data transmission in hybrid networks has two features:
An AP can be a source or a destination to any mobile node
It allows a stream to have anycast transmission along multiple transmission paths to its destination through base stations
The number of transmission hops between a mobile node and an AP is small
It enables a source node to connect to an AP through an intermediate node
In this paper introduce the QoS-Oriented Distributed routing protocol(QOD)
This QOD protocol makes five contributions:
QoS-guaranteed neighbor selection algorithm
Distributed packet scheduling algorithm
Mobility-based segment resizing algorithm
Soft-deadline based forwarding scheduling algorithm
Data redundancy elimination based transmission
EFFICIENT REBROADCASTING USING TRUSTWORTHINESS OF NODE WITH NEIGHBOUR KNOWLED...ijiert bestjournal
Mobile Ad hoc network is an infrastructure less communication network with limited resources. To maintain virtual
infrastructure for communication broadcasting mechanisms is used. Due to lack of energy efficiency in Mobile Ad
hoc network, there is a need to develop an efficient broadcasting model which enhances energy efficiency. Also
nodes with malicious behaviour cause an internal threat that disobeys the standard and degrades the performance of
routing protocols. This paper introduced an enhanced rebroadcasting algorithm, where rebroadcasting decision for
next hop is immediate or delayed on the basis of trust value and energy level of particular node. This approach helps
to decrease number of rebroadcast, energy consumption and also enhances security. The decision is made with trust
value associated with node, their remaining energy and total number of uncovered nodes.
An Improved Energy Efficient Wireless Sensor Networks Through Clustering In C...Editor IJCATR
One of the major reason for performance degradation in Wireless sensor network is the overhead due to control packet and packet delivery degradation. Clustering in cross layer network operation is an efficient way manage control packet overhead and which ultimately improve the lifetime of a network. All these overheads are crucial in a scalable networks. But the clustering always suffer from the cluster head failure which need to be solved effectively in a large network. As the focus is to improve the average lifetime of sensor network the cluster head is selected based on the battery life of nodes. The cross-layer operation model optimize the overheads in multiple layer and ultimately the use of clustering will reduce the major overheads identified and their by the energy consumption and throughput of wireless sensor network is improved. The proposed model operates on two layers of network ie., Network Layer and Transport Layer and Clustering is applied in the network layer . The simulation result shows that the integration of two layers reduces the energy consumption and increases the throughput of the wireless sensor networks.
Modified q aware scheduling algorithm for improved fairness in 802.16 j networksIJCNCJournal
Deployment of Multi-hop Relays in WiMax based Cellu
lar Networks is considered as a cost effective
solution to increase the Coverage area of Base Stat
ion and also to improve the Network Capacity with h
igh
quality short links. Scheduling became a challengin
g task in these Multi-hop Relay Wireless Cellular
Networks of IEEE 802.16j standard. H. Chen, X. Xie
and H. Wu proposed a Q-aware Scheduling
Algorithm in which back-pressure flow control mecha
nism is used to reflect current Q size of the Relay
s
and considered high back-pressure links to include
in Concurrent Transmission Scenarios, to maximize t
he
throughput. This focus on high back-pressure links,
leads to starvation of Mobile Stations having low
back-
pressure links, resulting unfairness in some cases.
To remedy this situation, a Fair Link Inclusion (F
LI)
mechanism is applied in Greedy Algorithm of Q-aware
Scheduling Algorithm. Simulation results show that
Modified Q-aware Scheduling Algorithm with FLI mech
anism has reasonable improvement in fairness and
maintaining steady throughput when compared with ex
isting algorithms.
Civilizing the Network Lifespan of Manets Through Cooperative Mac Protocol Me...IRJET Journal
1) The document discusses a proposed cooperative medium access control (CMAC) protocol for mobile ad-hoc networks (MANETs) that aims to improve energy efficiency and extend network lifetime.
2) Existing CMAC protocols focus on throughput enhancement but fail to adequately consider energy efficiency. The proposed DEL-CMAC protocol aims to extend network lifetime by accounting for energy consumption at both transmitters and receivers.
3) Cooperative communication techniques that employ relay nodes can provide spatial diversity gains to reduce transmission power needs. However, the overhead of cooperation may outweigh these gains, so an efficient CMAC protocol is required to manage medium access for cooperative transmissions.
The document proposes an Enhanced Heuristic Function based Energy Aware (EHF-EA) routing protocol for wireless sensor networks. EHF-EA aims to extend network lifetime and improve link quality by using a heuristic function to find optimal routes while considering longevity factor, link quality, and bandwidth. It constructs a network of 50 mobile homogeneous sensor nodes in clusters. EHF-EA computes heuristic and cost values to determine the best next hop to the destination, aiming to efficiently transfer data and conserve energy. Simulation results show EHF-EA achieves a 93.85% packet delivery ratio while reducing bandwidth and number of hops compared to other protocols.
Routing in Cognitive Radio Networks - A SurveyIJERA Editor
Cognitive Radio Networks (CRNs) have been emerged as a revolutionary solution to migrate the spectrum
scarcity problem in wireless networks. Due to increasing demand for additional spectrum resources, CRNs have
been receiving significant research to solve issues related with spectrum underutilization. This technology
brings efficient spectrum usage and effective interference avoidance, and also brings new challenges to routing
in multi-hop Cognitive Radio Networks. In CRN, unlicensed users or secondary users are able to use
underutilized licensed channels, but they have to leave the channel if any interference is caused to the primary or
licensed users. So CR technology allows sharing of licensed spectrum band in opportunistic and non-interfering
manner. Different routing protocols have been proposed recently based on different design goals under different
assumptions.
Performance Analysis of Enhanced Opportunistic Minimum Cost Routingin Mobile ...IJERA Editor
Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network with
infrastructure less environment to establish a data transmission between nodes within the network. A routing
protocol is used to discover routes between nodes. In this paper, we study the three existing routing protocols
namely AODV, DSDV and DSR to analyze theirperformance based on set of parameters.AODV and DSR
deliver almost all the packets compared to DSDV. Hence we try to modify the AODVprotocol and use in the
cooperative transmission.
In this paper, we study the cooperative transmission at the network layer and cooperative diversity at the
physical layer as a joint optimization of the transmission power in a Mobile Ad-Hoc Network (MANET) with
static channel. However due to variable wireless channels static routing is suboptimal. Proposed protocol
proactively selects forwarding nodes that work cooperatively forwarding the packet towards the destination.
Cooperative transmission side diversity helps in reducing interference. Diversity can be achieved at the physical
layer by coordinating the multiple nodes. Nodes are equipped with Omni-directional antenna and take the
advantages of transmission side diversity to achieve energy saving, under the assumption that channel gains are
available at the transmitters.
The proposed Opportunistic Minimum Cost Cooperative Transmission Shortest Path (OMCTSP) algorithms
select the best optimum route with minimum cost in terms of energy, number of hops, available bandwidth, link
quality (SNR) and outage probability. As the network becomes larger, finding optimal routes becomes
computationally intractable as the complexity of the dynamic programming (DP) approach increases as o (22n)
where n is the number of nodes in the networks. Hence we develop two suboptimal algorithms have complexity
of o (n2) perform as same as optimal algorithm. Also developthe Opportunistic Cooperative Routing in MANET
(O_CORMAN), which is a network layer opportunistic routing scheme for mobile ad hoc networks. Nodes in
the network use the components proactive routing protocol, forwarder list update and local re-transmission. We
evaluate the performance using NS 2.32 simulator there is significant performance improvement with respect to
energy, throughput packet delivery, and delay compared with Modified AODV (OMCTSP).
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
A novel routing technique for mobile ad hoc networks (manet)ijngnjournal
Actual network size depends on the application and the protocols developed for the routing for this kind of
networks should be scalable and efficient. Each routing protocol should support small as well as large
scale networks very efficiently. As the number of node increase, it increases the management functionality
of the network. Graph theoretic approach traditionally was applied to networks where nodes are static or
fixed. In this paper, we have applied the graph theoretic routing to MANET where nodes are mobile. Here,
we designed all identical nodes in the cluster except the cluster head and this criterion reduces the
management burden on the network. Each cluster supports a few nodes with a cluster head. The intracluster
connectivity amongst the nodes within the cluster is supported by multi-hop connectivity to ensure
handling mobility in such a way that no service disruption can occur. The inter-cluster connectivity is also
achieved by multi-hop connectivity. However, for inter-cluster communications, only cluster heads are
connected. This paper demonstrates graph theoretic approach produces an optimum multi-hop connectivity
path based on cumulative minimum degree that minimizes the contention and scheduling delay end-toend.
It is applied to both intra-cluster communications as well as inter-cluster communications. The
performance shows that having a multi-hop connectivity for intra-cluster communications is more power
efficient compared to broadcast of information with maximum power coverage. We also showed the total
number of required intermediate nodes in the transmission from source to destination. However, dynamic
behavior of the nodes requires greater understanding of the node degree and mobility at each instance of
time in order to maintain end-to-end QoS for multi-service provisioning. Our simulation results show that
the proposed graph theoretic routing approach will reduce the overall delay and improves the physical
layer data frame transmission.
This document compares the performance of three routing protocols for mobile ad hoc networks (MANETs): AOMDV, AOMDV with location information using the DREAM protocol, and AOMDV with energy information. AOMDV is a multipath routing protocol that finds multiple disjoint paths between nodes. AOMDV with DREAM uses location information to route packets more efficiently. AOMDV with energy information selects paths based on the residual energy of nodes to improve energy efficiency and network lifetime. The document provides an overview of these three protocols and reviews previous work comparing their performance based on metrics like energy consumption, packet delivery ratio, and throughput.
Hybrid networks is integrate MANETs and infrastructure wireless networks
It have proven to be a better network structure for the next generation networks
It can act Base station and Ad hoc according to the environment conditions
The widespread use of mobile devices the increasing demand for mobile multimedia streaming services
The future of real time need of high Quality of Service (QoS) support in wireless and mobile networking environments
The QoS support reduces end to end transmission delay and enhances throughput to guarantee the seamless communication between mobile devices and wireless infrastructures
Specifically, infrastructure networks improve the scalability of MANETs, while MANETs automatically establish self-organizing networks, extending the coverage of the infrastructure networks
This document summarizes a research project on developing an energy efficient routing protocol for mobile ad hoc networks. It discusses how current routing protocols do not consider energy efficiency. The proposed Energy Efficient Source Routing Protocol (EESR) aims to reduce energy consumption, balance energy usage across nodes, and increase network lifetime. EESR selects routes based on a cost metric that considers transmission power, distance between nodes, and remaining battery capacity. Simulation results show EESR increases remaining power levels, lowers variations in power levels, and improves packet delivery rate compared to the Dynamic Source Routing protocol.
This document describes an online tutoring service for digital signal processing homework and projects. It provides tutors experienced in digital signal processing to help with assignments and long-term projects. The document also includes sample MATLAB code for a GUI that implements quadrature amplitude modulation (QAM) with functions for various toggle buttons that create figures or exit the program.
1) The document describes an experiment on Quadrature Amplitude Modulation (QAM).
2) QAM is introduced as a digital modulation technique that modulates two analog/digital messages by changing the amplitude of two carrier waves that are out of phase.
3) Matlab code is provided to simulate QAM modulation and demodulation of signals with different frequencies to demonstrate how QAM works.
Performance Evaluation of Different QAM Techniques Using Matlab/Simulink full...vnktrjr
This document discusses the performance evaluation of different quadrature amplitude modulation (QAM) techniques using MATLAB/Simulink. It aims to develop a Simulink model to simulate various QAM modulation and demodulation schemes at bit rates ranging from 8 to 256 bits. The model transmits a randomly generated signal through an additive white Gaussian noise channel. It then measures the bit error rate versus the ratio of bit energy to noise power spectral density to evaluate each QAM technique's performance. The document explains QAM modulation mathematically and discusses signal constellations for different QAM orders. It also outlines the methodology and implementation of the Simulink model, including the use of a random integer generator and additive white Gaussian noise channel.
The document provides a summary of AIESEC's quarterly assessment meeting covering various areas including exchange development, marketing, business development, external relations, communications, expansions, talent development, information management, finance, and human resources.
Key areas of concern across departments included low RMR performance, lack of sustainable processes, failure to meet targets, inadequate partner engagement, and lack of standardized operations and accountability. Financial obligations were also noted as a liability. Overall, the meeting assessed performance in the first quarter and identified weaknesses to address in order to improve outcomes going forward.
The document describes a digital Quadrature Amplitude Modulation (QAM) transmitter. It discusses how QAM digitally modulates information onto the amplitudes of a sine and cosine wave, or equivalently onto the amplitude and phase of a single sinusoid. The transmitter uses pulse shaping filters and a Hilbert transformer to generate the in-phase and quadrature signals from the digital bit stream before upconverting and transmitting. Performance analysis methods for QAM are also presented to calculate decision regions and probabilities of correct detection.
In this video, I will explain what is QAM modulation and what is 16QAM.
QAM Stands for Quadrature Amplitude Modulation. QAM is both an analog and a digital modulation method. But here, we are only talking about QAM as a digital modulation.
Quadrature means that two carrier waves are being used, one sine wave and one cosine wave. These two waves are out of phase with each other by 90°, this is called quadrature.
At the receiving end, the sine and cosine wave can be decoded independently, this means that by using both a sine wave and a cosine wave, the communication channel's capacity is doubled comparing to using only one sine or one cosine wave. That is why quadrature is such a popular technique for digital modulation.
QAM modulation is a combination of Amplitude Shift Keying and Phase Shift Keying, both carrier wave is modulated by changing both its amplitude and phase. As shown in this 8QAM waveform, the top is the sine wave carrier, for bit 000, the sin wave has a phase shift of 0°, and an amplitude of 2. While for bit 110, the phase shift is 180°, and the amplitude now is 1. So both phase and amplitude are changed.
In 16QAM, the input binary data is combined into groups of 4 bits called QUADBITS.
As shown in this picture, the I and I' bits are sent to the sine wave modulation path, and the Q and Q' bits are sent to the cosine wave path. Since the bits are split and sent in parallel, so the symbol rate has been reduced to a quarter of the input binary bit rate. If the input binary data rate is 100 Gbps, then the symbol rate is reduced to only 25 Gbaud/second. This is the reason why 16QAM is under hot research for 100Gbps fiber optic communication.
The I and Q bits control the carrier wave's phase shift, if the bit is 0, then the phase shift is 180°, if the bit is 1, then the phase shift is 0°.
The I' and Q' bits control the carrier wave's amplitude, if bit is 0, then the amplitude is 0.22 volt, if the bit is 1, then the amplitude is 0.821 volt.
So each pair of bits has 4 different outputs. Then they are added up at the linear summer. 4X4 is 16, so there is a total of 16 different combinations at the output, that is why this is called 16QAM.
This illustration shows an example of how the QUADBIT 0000 is modulated onto the carrier waves.
Here I and I' is 00, so the output is -0.22 Volt at the 2-to-4-level converter, when timed with the sine wave carrier, we get -0.22sin(2πfct), here fc is the carrier wave's frequency. QQ' is also 00, so the other carrier wave output is -0.22cos(2πfct).
Here is the proof that quadbit 0000 is modulated as a sine wave with an amplitude of 0.311volt and a phase shift of -135°. You can now pause for a moment to study the proof.
This list shows the 16QAM modulation output with different amplitude and phase change for all 16 quadbits. On the right side is the constellation diagram which shows the positions of these quadbits on a I-Q diagram.
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Fault Tolerant Parallel Filters Based On Bch CodesIJERA Editor
Digital filters are used in signal processing and communication systems. In some cases, the reliability of those
systems is critical, and fault tolerant filter implementations are needed. Over the years, many techniques that
exploit the filters’ structure and properties to achieve fault tolerance have been proposed. As technology scales,
it enables more complex systems that incorporate many filters. In those complex systems, it is common that
some of the filters operate in parallel, for example, by applying the same filter to different input signals.
Recently, a simple technique that exploits the presence of parallel filters to achieve multiple fault tolerance has
been presented. In this brief, that idea is generalized to show that parallel filters can be protected using Bose–
Chaudhuri–Hocquenghem codes (BCH) in which each filter is the equivalent of a bit in a traditional ECC. This
new scheme allows more efficient protection when the number of parallel filters is large.
An Approach to Calculate Reusability in Source Code Using MetricsIJERA Editor
Reusability is an only one best direction to increase developing productivity and maintainability of application. One must first search for good tested software component and reusable. Developed Application software by one programmer can be shown useful for others also component. This is proving that code specifics to application requirements can be also reused in develop projects related with same requirements. The main aim of this paper proposed a way for reusable module. An process that takes source code as a input that will helped to take the decision approximately which particular software, reusable artefacts should be reused or not.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
AN OPTIMUM ENERGY CONSUMPTION HYBRID ALGORITHM FOR XLN STRATEGIC DESIGN IN WSN’SIJCNCJournal
In this paper, X-Layer protocol is originated which executes mobility error prediction (MEP) algorithm to calculate the remaining energy level of each node. This X-Layer protocol structure employs the mobility aware protocol that senses the mobility concerned to each node with the utilization of Ad-hoc On-Demand Distance Vector (AODV), which shares the information or data specific to the distance among individual nodes. With the help of this theory, the neighbour list will be updated only to those nodes which are mobile resulting in less energy consumption when compared to all (static/mobile) other nodes in the network. Apart from the MEP algorithm, clustering head (CH) election algorithm has also been specified to identify the relevant clusters whether they exists within the network region or not. Also clustering multi-hop routing (CMHR) algorithm was implemented in which the node can identify the cluster to which it belongs depending upon the distance from each cluster surrounding the node. Finally comprising the AODV routing protocol with the Two-Ray Ground method, we implement X-Layer protocol structure by considering MAC protocol in accordance to IEEE 802.15.4 to obtain the best results in energy consumption and also by reducing the energy wastage with respect to each node. The effective results had been illustrated through Network Simulator-II platform.
IRJET- Sink Mobility based Energy Efficient Routing Protocol for Wireless Sen...IRJET Journal
The document describes a proposed sink mobility based energy efficient routing protocol for wireless sensor networks. The protocol uses both a static centralized sink and a mobile sink that follows a predetermined path with 4 sojourn locations. This is aimed to improve network lifetime by balancing energy load across nodes. Simulation results show that the proposed approach with a mobile sink performs better than the Threshold sensitive Energy Efficient sensor Network (TEEN) protocol alone in terms of number of alive nodes, number of cluster heads, and number of packets sent to the base station over multiple rounds. Using a mobile sink helps scatter the energy load in the network and extends lifetime compared to only using a static sink.
An Integrated Approach of ACM and CDMA in a Novel Multi User Spatial Modulati...ijtsrd
This document discusses a proposed novel multi-user spatial modulation scheme that integrates adaptive coding and modulation (ACM). It begins with background on spatial modulation techniques and their advantages over other MIMO techniques in reducing complexity while maintaining spectral efficiency. It then presents the system model for the proposed two-user multiple access spatial modulation system, which introduces a switching unit to dynamically select modulation orders for each transmit antenna based on channel conditions, as determined by a receiver with an adaptive unit. This adaptive approach aims to improve performance by optimizing modulation levels according to channel state information feedback from the receiver to the transmitters.
GPS Enabled Energy Efficient Routing for ManetCSCJournals
In this paper, we propose an energy aware reactive approach by introducing energy and distance based threshold criteria. Cross Layer interaction is exploited the performance of physical layer which leads to significant improvement in the energy efficiency of a network.
This document describes a hybrid Particle Swarm Optimization - Bat Algorithm (HPSO-BA) with fuzzy logic routing technique to maximize lifetime in wireless sensor networks while constraining delay. The proposed method uses HPSO-BA to optimize energy efficiency in the sensor network's shortest path trees. A fuzzy logic approach is also used to combine multiple metrics for routing decisions. Simulation results show the technique achieves a good balance between increased network lifetime and reduced end-to-end delay.
IRJET-Spectrum Allocation Policies for Flex Grid Network with Data Rate Limit...IRJET Journal
This document discusses spectrum allocation policies for flex grid networks with data rate limited transmission. It begins with an abstract that outlines the tradeoff between data rate, allocated frequency slots, and modulation format that must be considered for spectrum allocation. It then discusses the objectives of identifying optical paths, path lengths, selecting modulation schemes, and finding optimal routes. The methodology section covers factors considered for spectrum allocation like modulation formats, noise, crosstalk, and transmission distances limited by noise and crosstalk for different modulation formats and fiber core counts. Implementation details algorithms for network setup, finding shortest paths, candidate path selection, and spectrum allocation. Results show fragmentation increases with demand but is constant for some core fibers. Higher core counts provide advantages and lower request
Enhancing Performance for Orthogonal Frequency Division Multiplexing in Wirel...IRJET Journal
The document discusses enhancing the performance of Orthogonal Frequency Division Multiplexing (OFDM) in wireless systems. It proposes using a technique called Selective Level Mapping (SLM) to reduce the peak-to-average power ratio (PAPR) of OFDM signals. PAPR reduction is important for OFDM systems to improve power amplifier efficiency. The document describes a "Class-III SLM scheme" that can generate multiple alternative OFDM signal sequences using only one inverse fast Fourier transform, helping to reduce complexity. It proposes a selection method for rotation values that can achieve optimal PAPR reduction while balancing the load across components. Simulation results show the proposed method achieves better PAPR reduction performance than conventional methods
Servant-ModLeach Energy Efficient Cluster Base Routing Protocol for Large Sca...IRJET Journal
The document proposes a new routing protocol called Servant-MODLEACH (S-MODLEACH) to address some challenges in the MODLEACH protocol for wireless sensor networks. S-MODLEACH introduces servant nodes that are responsible for data aggregation to reduce the workload on cluster heads. It also selects cluster heads based on residual energy rather than probability, allowing nodes with higher energy to serve as cluster heads for longer. Simulation results showed S-MODLEACH performs better than MODLEACH in terms of throughput, energy conservation, and extending network lifetime.
Q-LEARNING BASED ROUTING PROTOCOL TO ENHANCE NETWORK LIFETIME IN WSNSIJCNCJournal
In resource constraint Wireless Sensor Networks (WSNs), enhancement of network lifetime has been one of the significantly challenging issues for the researchers. Researchers have been exploiting machine learning techniques, in particular reinforcement learning, to achieve efficient solutions in the domain of WSN. The objective of this paper is to apply Q-learning, a reinforcement learning technique, to enhance the lifetime of the network, by developing distributed routing protocols. Q-learning is an attractive choice for routing due to its low computational requirements and additional memory demands. To facilitate an agent running at each node to take an optimal action, the approach considers node’s residual energy, hop length to sink and transmission power. The parameters, residual energy and hop length, are used to calculate the Q-value, which in turn is used to decide the optimal next-hop for routing. The proposed protocols’ performance is evaluated through NS3 simulations, and compared with AODV protocol in terms of network lifetime, throughput and end-to-end delay.
Enhancing Survivability, Lifetime, and Energy Efficiency of Wireless NetworksIJRES Journal
In this paper, we focus on improving wireless networks survivability in terms of increasing network lifetime and its energy efficiency via clustering the network in an efficient way. Clustering the network is the procedure of partitioning it into groups, where each of them is known as a cluster. Each cluster elects the station with the highest power to be a cluster head. The remaining stations follow the nearest cluster head. Instead of having each station sends its packets to a remote receiver, the cluster head receives packets from all stations within its cluster, aggregates them, and forwards the resulting packets to the remote receiver. The most significant benefit of clustering the network that we focus on is to decrease distances between sending and receiving stations, which in turn reduces the transmission energy. This reduction in the energy yields an increase in the network lifetime and its survivability.
A scalable and power efficient solution for routing in mobile ad hoc network ...ijmnct
This document summarizes a research paper that proposes a scalable and power-efficient routing solution for mobile ad hoc networks (MANETs). The paper describes a cluster-based MANET architecture and develops a graph theoretic routing algorithm that finds paths from source to destination nodes using routes with minimum cumulative degree. Simulation results show that the algorithm provides efficient routing paths even as the number of nodes increases, and uses multi-hop connectivity to transmit packets using minimum power irrespective of the number of nodes in the network. The algorithm is shown to be scalable and power efficient compared to other routing methods.
EFFICIENT ANALYSIS OF THE ERGODIC CAPACITY OF COOPERATIVE NON-REGENERATIVE RE...ijwmn
This paper proposes a novel efficient method to analyze the ergodic channel capacity of cooperative amplify-and-forward relay systems. This is accomplished by employing a very tight approximate moment generating function of the end-to-end signal-to-noise ratio that is applicable to various fading environments, including mixed and composite fading channels. Three adaptive source transmission policies are considered: constant power with optimal rate adaptation, optimal joint power and rate adaptation, and fixed rate with truncated channel inversion. Closed-form expressions for ergodic capacity under these policies are derived for Nakagami-m fading with independent but not identically distributed statistics. The accuracy of the proposed approximate method is validated through existing results and Monte Carlo simulations.
EFFICIENT ANALYSIS OF THE ERGODIC CAPACITY OF COOPERATIVE NON-REGENERATIVE RE...ijwmn
In this paper, we proposed a novel efficient method of analyzing the ergodic channel capacity of the
cooperative amplify-and-forward (CAF) relay system. This is accomplished by employing a very tight
approximate moment generating function (MGF) of end-to-end signal-to-noise ratio of 2-hop multi-relay
system, which is In this paper, we proposed a novel efficient method of analyzing the ergodic channel
capacity of the cooperative amplify-and-forward (CAF) relay system. This is accomplished by employing a
very tight approximate moment applicable to myriad of fading environments including mixed and
composite fading channels. Three distinct adaptive source transmission policies were considered in our
analysis namely: (i) constant power with optimal rate adaptation (ORA); (ii) optimal joint power and rate
adaptation (OPRA); and (iii) fixed rate with truncated channel inversion (TCIFR). The proposed frame
work based on the novel approximate MGF method is sufficiently general to encapsulate all types of fading
environments (especially for the analysis of the mixed fading case)and provides significant advantage to
model wireless system for mixed and composite fading channel. In addition to simplifying computation
complexity of ergodic capacity for CAF relaying schemes treated in literature, we also derive closed form
expressions for the above three adaptive source transmission policies under Nakagami-m fading with i.n.d
statistics. The accuracy of our proposed method has been validated with existing MGF expressions that are
readily available for specific fading environments in terms of bounds, and via Monte Carlo simulations.
Performance Analysis and Comparison of Routing Protocols in Wireless Sensor N...IRJET Journal
This document analyzes and compares the performance of different routing protocols in wireless sensor networks. It first discusses existing routing protocols like LEACH, LEACH-C, and PEGASIS and their limitations. It then proposes a new Static Clustering Based Multi-hop Routing (SCMR) algorithm where clusters are formed statically before network deployment and do not change. The SCMR algorithm is simulated and analysis shows it has lower energy consumption, longer network lifetime, and higher packet delivery ratio compared to LEACH.
A Review Paper on Power Consumption Improvements in WSNIJERA Editor
Wireless Sensor network (WSN) is a network of low-cost, low-power, multifunctional, small
size sensor nodes which are densely deployed inside a physical environment to collect, process and transmit the
information to sink node. As Sensor nodes are generally battery-powered, it is necessary to balance between
power consumption and energy storage capacity to sustain sensor node's operational life. Therefore one of the
important challenge in WSN is to improve power consumption efficiently to prolong network lifetime by
minimizing the amount of data transmissions throughout the network and maximizing node's low power
residence time. In this paper, two energy optimization techniques, Cluster-Based energy efficient routing
(CBER) scheme and extension to IEEE 802.15.4 standard by dynamic rate adaption and control for energy
reduction (DRACER) protocol for wireless sensor networks has been reviewed. CBER technique increases
network lifetime by reducing Hot Spot problem and end-to-end energy consumption using multi-hop wireless
routing whereas DRACER protocol reduces network latency and average power consumption by minimizing
network overhead using automatic data rate selection process. So, both of these techniques, if utilized in
combination, it is possible to achieve very high energy efficiency in WSN
A Novel Timer-Based Hybrid Rerouting Algorithm for Improving Resource Utiliza...IJERA Editor
In this paper we investigate hybrid rerouting and minimization of incurred service disruption period due to
rerouting in Wavelength Division Multiplexed (WDM) transparent optical network. One limitation of such a
network is the wavelength continuity constraint which does not allow a circuit to be placed on a non
wavelength-continuous route. The impact of this constraint might have a severe consequence on the
performance of transparent optical networks especially in terms of rejection ratio ant it is especially severe when
traffic demands are unpredictable and characterized by random arrivals and departures. To alleviate the impact
of these constraints, either wavelength conversion or traffic rerouting can be used. Since, in the foreseeable
future, wavelength conversion is expected to remain an expensive technology, traffic rerouting is an attractive
alternative solution. Thus, we here propose to employ hybrid rerouting to improve the network performances.
Hybrid rerouting combines passive and active rerouting. Through simulation results, the performances of the
proposed algorithm in terms of rejection ratio are demonstrated to be promising while rerouting a small number
of already established lightpaths using Lightpath ReRouting (LRR). By rerouting a small number of existing
lightpaths using LRR, we hope that the incurred service disruption period due to rerouting is minimized.
This document summarizes a research paper that proposes a novel cross-layer routing technique for mobile ad hoc networks. The technique calculates both signal strength and node mobility to select the most efficient and stable path for data transmission. It aims to improve on traditional ad hoc routing protocols like AODV by considering both link quality metrics from the physical layer (signal strength) and node mobility. The proposed method selects routes based on signal strength if mobility is high, and on traditional hop count if mobility is low, in order to find paths that reduce link failure and improve throughput.
Reduced Test Pattern Generation of Multiple SIC Vectors with Input and Output...IJERA Editor
In recent years, the design for low power has become one of the greatest challenges in high-performance very
large scale integration (VLSI) design. Most of the methods focus on the power consumption during normal mode
operation, while test mode operation has not normally been a predominant concern. However, it has been found
that the power consumed during test mode operation is often much higher than during normal mode operation
[1]. This is because most of the consumed power results from the switching activity in the nodes of the circuit
under test (CUT), which is much higher during test mode than during normal mode operation [1]–[3]. In the
proposed pattern, each generated vector applied to each scan chain is an SIC vector, which can minimize the
input transition and reduce test power. In VLSI testing, power reduction is achieved by increasing the correlation
between consecutive test patterns.
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Improving Power Efficiency in Cooperative Diversity and MIMO Systems by Using Star QAM
1. Abdussayeed Khan Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 5, Issue 8, (Part - 2) August 2015, pp.61-66
www.ijera.com 61|P a g e
Improving Power Efficiency in Cooperative Diversity and MIMO
Systems by Using Star QAM
Abdussayeed Khan, Mohammad Shabber Hasan Khan
Master of Science in Electronics
Master of Science in Electronics
Abstract
In this paper, we propose a new simple relaying strategy based on bit-interleaved convolutionally coded
starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this
property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay. Here we are using the
higher order modulation for improving relay communication, and also employ the accurate relay technique.
Moreover, we show that the proposed approach retains differential detectability, which results in a significant
reduction of receiver complexity with robustness against phase ambiguity, by analyzing our proposed method in
terms of asymptotic pairwise error probability (PEP), Furthermore, the effectiveness of the proposed scheme in
terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous
signal power. And also implement the PEP in MIMO systems for improving the powerefficiency. All the
theoretical results agree with those obtained by computer simulations.
Index Terms—Cooperative diversity, power amplifier (PA)efficiency, star-quadrature amplitude modulation
(star-QAM), differential amplitude-and-phase shift keying (DAPSK), amplify and- forward (AF),MIMO
systems.
I. Introduction
Utilization of terminals distributed in space can
significantlyimprove the performance of wireless
networks
[1]–[3]. For example, pair of neighboring nodes
with channel state information (CSI) can
cooperatively beamformtowards the final destination
to increase total capacity [2]. Even when CSI is not
available or when radio hardware cannot support
beamforming, cooperation between the source and a
single relay provides improved robustness to wireless
fading [3]. Basic results for cooperation are presented
in [4]–[6] and references therein. Scaling cooperation
to more than one relay is still an open area of
research, despite the recent interest in cooperative
communication. One possible approach is the use of
distributed space–time coding among participating
nodes [7]. In practice, such code design is quite
difficult due to the distributed and ad-hoc nature of
cooperative links, as opposed to codes designed for
co-located multiple-input multiple output(MIMO)
systems [8]–[10]. The need and availability of global
CSI is fundamental in distributed environments. For
example, additional communication is needed for
each relay to acquire CSI about other relays (as
needed in [11]) or for the destination to acquire CSI
between the source and all relays (as needed in [12]).
Moreover, the number of useful antennas (distributed
relays) for cooperation is generally unknown and
varying. Therefore, coordination among the
cooperating nodes is needed prior to the use of a
specific space–time coding scheme, typically
designed for a fixed number of transmit antennas.
Furthermore, it is often assumed in the literature that
the superposition of signals transmitted by several
relays is always constructive.1 such assumption
requires distributed phased-array techniques
(beaforming) and unconventional radios, thereby
increasing complexity and cost of each transmitter.
Finally, coherent reception of multiple-relay (MR)
transmissions requires tracking of carrier-phase
differences among several transmit receivepairs,
which increases the cost of the receiver. Therefore,
simplification of radio hardware in cooperative
diversity setups is important. Antenna selection,
invented for classical multiple-antenna
communications [14]–[18], is one approach to
minimize the required cooperationoverhead and to
simultaneously realize the potential benefits of
cooperation between multiple relays. In particular, a
simple, distributed, single-relay selection algorithm
was proposed for slow fading of the wirelessrelay
channels [19]. This single-relay
opportunisticselection provides no performance loss
from the perspective of diversity–multiplexing gain
tradeoff, compared to schemes that rely on
distributed space–time coding. In this paper, we
present single-selection—opportunistic— relaying
with decode-and-forward (DaF) and amplify-and
forward(AaF) strategies and analyze their outage
probability under an aggregate power constraint.2
The motivation behind imposing the aggregate power
RESEARCH ARTICLE OPEN ACCESS
2. Abdussayeed Khan Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 5, Issue 8, (Part - 2) August 2015, pp.61-66
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constraint is threefold: (i) transmission power is a
network resource that affects both the lifetime of the
network with battery-operated terminals and the
scalability of the network; (ii) regulatory agencies
may limit total transmission power due to the fact
that each transmission can cause interference to the
others in the network; and (iii) cooperative diversity
benefits can be exploited even whenrelays do not
transmit (and therefore, do not add transmission
energy into the network). We consider both reactive
and proactive relay selection depending on whether
the relay selection is performed after or before the
source transmission. This paper is organized as
follows. In Section II, we briefly describe a system
model and the three relay functions; AF, DetF, and
our proposed relaying with either coherent or
differential detection. Section III analyzes an
asymptotic pairwise error probability (PEP) of the
proposed system and shows that it can achieve the
full diversity order on the condition that the
minimum free distance of the convolutional codes is
larger than the predetermined value specified by the
number of relay terminals regardless of detection
schemes. In Section IV, an asymptotic peak power
efficiency is theoretically analyzed under the band-
limited scenario. In Section V, theoretical results and
the effectiveness of PA efficiency are confirmed by
computer simulations. Finally, Section VI concludes
this work.
In this paper, we propose a new simple relaying
strategy based on bit-interleaved convolutionally
coded star-QAM. Star-QAM was originally proposed
as a special case of circular amplitude and phase shift
keying (APSK) modulation [11] which is
advantageous to square-shaped QAM modulation in
terms of achievable mutual information over peak
power limited channels [12, 13] and has recently
become widely adopted, due primarily to its inclusion
in the second generation of the Digital Video
Broadcasting Satellite standard, DVBS2[14, 15], as
well as some other satellite standards such as DVB-
SH, IPoS, and ABS-S. Star-QAM iscomposed of
multiple concentric circles of phase-shift keying
(PSK), where every PSK ring has the same number
of symbols and is constructed with an identical phase
offset. The main advantage of star-QAM
constellation is mutual independence between
amplitude and phase of each signal point in the
constellation [16, 17]. This unique property allows
the receiver to use differential detection instead of
coherent detection, which requires neither a channel
estimation nor accurate phase tracking at the receiver.
Star-QAM, hence, was principally investigated with
differential detection [18–21] and is also referred to
as a differential amplitude and phase shift keying
(DAPSK) in the literature [22]. In this paper we
exploit this unique property of star-QAM signaling;
independence of phase and amplitude. The relay
suppresses the amplitude variation of the received
signals due to the use of a hard limiter [23] and
transmits the resulting PSK signals in order to
enhance the PA efficiency at the relay. It is worth
noting that, in our proposed approach, its complexity
is comparable to AF relaying rather than DetF
relaying since neither demodulation nor decoding is
required during relaying process. Moreover, owing to
the property of star-QAM constellation, our approach
has differential detectability, which does not require
accurate channel estimation. A study on single and
multiple relay systems using differential phase shift
keying (DPSK) modulation can be found in [24] and
[25], respectively. These conventional approaches
with differential detection lead to a low complexity
receiver structure but apparently face with a
considerable reduction of PA efficiency as the
bandwidth efficiency increases. On the other hand,
our approach with differential detection can achieve
higher bandwidth efficiency with neither increase of
complexity nor reduction of PA efficiency.
II. PROPOSED METHOD
2.1. Cooperative Relaying Model:
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In this paper, we consider a network consisting
of the three terminals denoted as source, relay, and
destination. Each terminal is equipped with a single
antenna and the relay is subject to the half-duplex
constraint. That is, we assume that while listening to
the channel, the relay may not transmit. Figure 1
shows the mathematical system model with this
single relay scenario. Throughout the paper, we
consider a star-QAM constellation. Star-QAM is
composed of 2(m−n) concentric circles of2n-ary
PSK. A radius of the lth circle is given by
(1)
When a differential detection is assumed at the
receiver side, the corresponding differential encoding
at the source is necessary. Let the kth transmit
symbol be denoted as X(k) = rkejθk, where rkand
θkdenote the envelope and the angle of the kth
transmit signal, respectively. Then, the first nbits of
the kthcodeword choose the phase difference between
two consecutive symbols θkand θk−1 together with
Gray labeling while the remaining (m−n) bits choose
the amplitude difference between rk−1 and rk[20].
For 16-DAPSK systems, the first three coded bits
choose the phase difference between two consecutive
symbols and remaining one coded bit, say c ∈ {0, 1},
chooses rk∈ {A0,A1} by the following rule:
2.2. Conventional Relaying:
2.2.1. AF Relay: When the envelope of the channel
coefficient of the source-relay link is fully available
at therelay, AF relay can be used [5]. The relay
function of AF relaying is then given by
(2)
In the case of AF relaying, neither demodulation
nor decoding is needed at the relay since the relay
only retransmits the amplified version of the received
signal
(3)
2.2.2. Coherent Detect-and-Forward (CDetF) Relay:
In the case of CDetF relaying, the relay detects the
received signal and transmits a regenerated signal.
Hence, the relay function of this relaying with
coherent detection can be given by
(4)
2.2.3. Noncoherent Detect-and-Forward (NDetF)
Relay:
Similarly as in the CDetF relaying, aNDetF
relay retrieves the original signals by using the
differential detection without decoding. According to
[20], the estimated phase difference Δˆθkis given by
(5)
2.2.4.. The Proposed Relaying:
To avoid an event that high instantaneous power
of the transmitted signal at the relay occurs, we
propose a new simple relaying technique using a hard
limiter [23] whose complexity is less than that of AF
relaying since it does notrequire any knowledge of
wireless links. Figure 3 illustratesthe relationship
between the input and output envelope levels of the
hard limiter in comparison with that of AF relaying
where GAF is assumed to be one. As observed from
the figure, hard limiter always provides a given
constant amplitude for any input envelope. The
proposed relaying utilizes thisunique characteristic of
hard limiter to suppress the amplitude variation of
received signal while retaining its phase rotation and
then transmits the signals with the constant envelope,
which can be mathematically expressed as
4. Abdussayeed Khan Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 5, Issue 8, (Part - 2) August 2015, pp.61-66
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(6)
Whereϕkdenotes the angle of the kth received signal.
Afterthe hard limitation, the constellation of 2m-ary
star-QAM reduces to that of 2n-ary PSK because of
the elimination ofamplitude information as depicted
in Fig. 4. Hereinafter, letMdenote a set of complex
PSK signal points with |M| = 2nand unit average
energy.
III. PERFORMANCE ANALYSIS AND
DESIGN CRITERIA OFTHE
PROPOSED RELAYING
In this section, we analyze an asymptotic PEP of
the proposed approach along with coherent and
noncoherent detections to show that our proposed
approach can achieve full diversity (i.e., diversity
order of two in this scenario). Based on these
analytical results, essential design criteria of the
proposed relaying are presented.
3.1. Coherent Detection:
A code rate Rcconvolutional encoder with
minimum freedistanced is assumed to generate the
binary code sequence c at the source. If the bitwise
interleaved is ideal, the PEP of two code wordsc and
~c conditioned on Hsr, Hrd, Hsdcan be expressed as
3.2. Noncoherent Detection:
Similar to the coherent case, the proposed
approach canbe regarded as the bit-interleaved coded
DPSK and thusthe theoretical approach in [33] can be
applied. Thus, fromsuboptimal Gaussian metric
instead of bit metrics describedin Section II-D2, the
PEP without any channel informationcan be written
as
3.3. Complementary Cumulative Distribution
Function (CCDF) of Instantaneous Power:
Let s(τ ;H) indicate a complex baseband signal at
the relay using the arbitrary fading realization H
which is a positive real random variable following
Rayleigh distribution with unit variance1. Then s(τ
;H) is denoted by [9]where τ is a continuous time
scale normalized by its symbol period, g(τ ) is the
impulse response of the pulse shaping filterwith unit
average energy, K is an effective length of g(τ ) of
one-sided impulse response, and ak(τ ) , g(k + τ ). For
agiven time instant τ ∈ [0, 1) and fading coefficient
H, the probability that the instantaneous power
3.4. MIMO systems:
MIMO antenna configuration. In spatial
multiplexing, a high rate signal is split into multiple
lower rate streams and each stream is transmitted
from a different transmit antenna in the same
frequency channel. If these signals arrive at the
receiver antenna array with sufficiently different
spatial signatures and the receiver has accurate CSI, it
can separate these streams into (almost) parallel
channels.
IV. NUMERICAL RESULTS
In this section, we evaluate the performance of
our proposedapproach via computer simulations. We
first define a relative IBO gain to evaluate PA
efficiency and show performance in terms of the
CCDFs. Then, we show the performance comparison
in terms of bit error rate (BER) without considering
the effect of PA. Afterwards, we investigate the
performance of the three different cooperative
approaches in the presence of IBO of PA.
41.Instantaneous Power Distributions of Different
Relay Functions:
We here show some numerical examples for
instantaneous power distributions to evaluate PA
efficiency Figure 6 shows the theoretical curves for
the average CCDF of AF (uniform amplitude disk),
DetF (uniform amplitude disk), and the proposed
relaying (uniform PSK), where the SNR between the
source and relay is assumed to be 10 dB or 20 dB. As
seen in the figure, AF relaying has higher
instantaneous power than that of the other relays due
to the noisy characteristic of transmit signals before
the pulse shaping filter. Thus, the higher the SNR
5. Abdussayeed Khan Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 5, Issue 8, (Part - 2) August 2015, pp.61-66
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between the source and relay, the more rapidly the
CCDF curve of the AF relay drops owing to the
diminution of noisy components
of the proposed approach. In the following, the root
raised-cosine (RRC) pulse with a roll-off factor ν is
assumed as g(τ ), where its closed form expression is
given by [9]
While the DetF relay exhibits lower CCDF
performance than those of AF relay, there is still a
gap between the proposed and DetF relaying, which
is about 3.3 dB at CCDF = 10−3. Note that this gap
essentially leads to the improvement in the PA
efficiency.
4.2. BER Performance without IBO Effects:
1) Performance of Coherent Detection: We start with
the BER comparison without considering IBO
effects, where every receiver can use the coherent
detection to retrieve transmitted information. The
convolutional code with half rate (133, 171)8 and
dfree= 10 is assumed and a multiple random
interleaver is used, which meets all the design criteria
provided in Section III. The information size is 2 048
bits and the ring ratio α of star-QAM is assumed to
be 2.0 as a typical value. To consider the geometrical
proximity, we assume that the average received
signal power at the relay is assumed to be G = 10 dB
or 20 dB higher than that at the destination. Figure 7
shows the BER performance of the aforementioned
three cooperative transmissions; AF, CDetF, and
proposed
Performance Comparison with IBO Effects
Finally, we show the BER performances in the
presence ofIBO effects. From the results in Section
V-B, Fig. 9 shows the BER performance of
AF,CDetF, and the proposed relays using coherent or
noncoherent detection in the presence of relative IBO
gain at the relay. Interestingly, the performance of the
proposed approach based on coherent detection is
always superior to that of the other relays owing to
PA leading to effective reduction of instantaneous
high power signals. With the coherent detection
scenario, the performance gain of our proposed
approach is about 2.4 dB and 0.4 dB compared with
AF and CDetF cooperation at BER = 10−3,
respectively. Moreover, the proposed cooperation
with differential detection approaches AF relay with
coherent detection despite its simple structure while
there is 1 dB energy loss in the presence of relative
IBO gain. Therefore, our proposed approach is much
beneficial in terms of BER performance in addition
to PA efficiency and circuit simplicity.
V. CONCLUSIONS
In this paper, the power efficient relaying
strategy togetherwith bit-interleaved convolutionally
coded star-QAM has been proposed in combination
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with coherent and differential detection. Based on the
asymptotic PEP analysis, the design criteria of our
proposed approach were investigated and our results
indicated that full diversity for the proposed approach
is guaranteed regardless of the detection techniques.
We also derived the CCDFs of AF and DetF relays
with uniform amplitude disk, which confirmed the
effectiveness of PA efficiency of the proposed
approach. The benefits of the proposed approach
under the consideration of PA efficiency were
confirmed by the numerical results. Moreover,
although AF relaying can be seen as an attractive
candidate for low complexityrelaying compared with
DetFrelaying, the proposed approach requires neither
channel state information nor detection at the relay.
Our proposed approach, hence, can be considered as
a practical cooperative diversity relaying suitable for
energylimited applications. We can also implement
the proposed relaying technique in MIMO system.
ACKNOWLEDGMENTS
The authors would like to thank the Associate
Editor and anonymous reviewers for their comments
that improved thequality of manuscript.
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