This document summarizes research on the ergodic capacity of an underlay cognitive radio system operating under maximum and average received power constraints at the licensed primary user's receiver. It presents theoretical analysis and numerical simulations. The key findings are:
1) Ergodic capacity decreases as the maximum received power constraint increases or average received power decreases.
2) The optimal transmission cutoff threshold increases as the maximum received power constraint or primary receiver's average received power decreases.
3) For small average received powers, the impact of the maximum received power constraint is negligible. Ergodic capacity increases with average received power up to the maximum received power level, then decreases.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
Resource Allocation in MIMO – OFDM Communication System under Signal Strength...Kumar Goud
Abstract: - Multiple Inputs and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to attain high capability on the propagation setting. The aim of this paper is that the adaptive resource allocation in MIMO-OFDM system uses the water filling formula. Water filling answer is enforced for allocating the ability so as to extend the data rate. The overall system capability is maximised subject to the constraints on total power, signal to noise quantitative relation, and proportionality. Channel is assumed as a flat attenuation channel and therefore the comparison is created for various 2×2, 2×3, 3×2 and 4×4 MIMO-OFDM systems and water filling formula with allotted power. Supported the capability contribution from the relaying terminal, a brand new parameter referred to as cooperation constant is introduced as an operate of the relaying sub channel. This parameter is employed to switch the target parameter of the subcarrier allocation procedure. Fairness-oriented [Fading Channel] and throughput-oriented [Near finish Channel] algorithms square measure elite from the literature to check the planned technique. Each algorithms square measure changed to use the mean of cooperation constant within the objective parameter of the subcarrier allocation procedure and shown to own a much better total turnout with none sacrifice.
Keywords - MIMO-OFDM; Water filling Algorithm; Subcarrier Resource Allocation
Downlink beamforming and admissin control for spectrum sharing cognitive radi...acijjournal
n this paper, to detect the moving objects between frames in compressed video and to obtain the bes
t
compression video
and the noiseless video. We describe a video in which frames by classifying
macroblocks (MB), and describe motion estimation (ME), motion vector field (MV) and motion
compensation (MC). we propose to classify Macroblocks of each video frame into different
classes and use
this class information to describe the frame content based on the motion vector. MB class informatio
n
video applications such as shot change detection, motion discontinuity detection, Outlier rejection
for
global motion estimation. To reduc
e the noise and to improve the clarity of the compressed video by using
contrast limited adaptive histogram equalization (CLAHE) Algorithm
A STUDY ON QUANTITATIVE PARAMETERS OF SPECTRUM HANDOFF IN COGNITIVE RADIO NET...ijwmn
The innovation of wireless technologies requires dynamic allocation of spectrum band in an efficient
manner. This has been achieved by Cognitive Radio (CR) networks which allow unlicensed users to make
use of free licensed spectrum, when the licensed users are kept away from that spectrum. The cognitive
radio makes decision, switching from primary user to secondary user and vice-versa, based on its built-in
interference engine. It allows secondary users to makes use of a channel based on its availability i.e. on the
absence of the primary user and they should vacate the channel once the primary user re-enters and
continue their communication on another available channel and this process in the cognitive radio is
known as spectrum mobility. The main objective of spectrum mobility is that, there is no interruption
caused due to the channel occupied by secondary users and maintains a good quality of service. In order to
achieve better spectrum mobility, it is mandatory to choose an effective spectrum handoff strategy with the
capability of predicting spectrum mobility. The handoff strategy with its parameters and its impact is an
important concept in spectrum mobility but fairly explored. In this paper an empirical study on quantitative
parameters involved in spectrum mobility prediction are discussed in detail. These parameters are studied
extensively because they play a vital role in the spectrum handoff process moreover the impact of these
parameters in various handoff methods can be used to predict the effectiveness of the system.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
Resource Allocation in MIMO – OFDM Communication System under Signal Strength...Kumar Goud
Abstract: - Multiple Inputs and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to attain high capability on the propagation setting. The aim of this paper is that the adaptive resource allocation in MIMO-OFDM system uses the water filling formula. Water filling answer is enforced for allocating the ability so as to extend the data rate. The overall system capability is maximised subject to the constraints on total power, signal to noise quantitative relation, and proportionality. Channel is assumed as a flat attenuation channel and therefore the comparison is created for various 2×2, 2×3, 3×2 and 4×4 MIMO-OFDM systems and water filling formula with allotted power. Supported the capability contribution from the relaying terminal, a brand new parameter referred to as cooperation constant is introduced as an operate of the relaying sub channel. This parameter is employed to switch the target parameter of the subcarrier allocation procedure. Fairness-oriented [Fading Channel] and throughput-oriented [Near finish Channel] algorithms square measure elite from the literature to check the planned technique. Each algorithms square measure changed to use the mean of cooperation constant within the objective parameter of the subcarrier allocation procedure and shown to own a much better total turnout with none sacrifice.
Keywords - MIMO-OFDM; Water filling Algorithm; Subcarrier Resource Allocation
Downlink beamforming and admissin control for spectrum sharing cognitive radi...acijjournal
n this paper, to detect the moving objects between frames in compressed video and to obtain the bes
t
compression video
and the noiseless video. We describe a video in which frames by classifying
macroblocks (MB), and describe motion estimation (ME), motion vector field (MV) and motion
compensation (MC). we propose to classify Macroblocks of each video frame into different
classes and use
this class information to describe the frame content based on the motion vector. MB class informatio
n
video applications such as shot change detection, motion discontinuity detection, Outlier rejection
for
global motion estimation. To reduc
e the noise and to improve the clarity of the compressed video by using
contrast limited adaptive histogram equalization (CLAHE) Algorithm
A STUDY ON QUANTITATIVE PARAMETERS OF SPECTRUM HANDOFF IN COGNITIVE RADIO NET...ijwmn
The innovation of wireless technologies requires dynamic allocation of spectrum band in an efficient
manner. This has been achieved by Cognitive Radio (CR) networks which allow unlicensed users to make
use of free licensed spectrum, when the licensed users are kept away from that spectrum. The cognitive
radio makes decision, switching from primary user to secondary user and vice-versa, based on its built-in
interference engine. It allows secondary users to makes use of a channel based on its availability i.e. on the
absence of the primary user and they should vacate the channel once the primary user re-enters and
continue their communication on another available channel and this process in the cognitive radio is
known as spectrum mobility. The main objective of spectrum mobility is that, there is no interruption
caused due to the channel occupied by secondary users and maintains a good quality of service. In order to
achieve better spectrum mobility, it is mandatory to choose an effective spectrum handoff strategy with the
capability of predicting spectrum mobility. The handoff strategy with its parameters and its impact is an
important concept in spectrum mobility but fairly explored. In this paper an empirical study on quantitative
parameters involved in spectrum mobility prediction are discussed in detail. These parameters are studied
extensively because they play a vital role in the spectrum handoff process moreover the impact of these
parameters in various handoff methods can be used to predict the effectiveness of the system.
MPC-EAR : Maximal Power Conserved And Energy Aware Routing in Ad hoc Networksijsrd.com
Power preservation in wireless ad hoc networks is a decisive factor as energy resources are inadequate at the electronic devices in use. Power-aware routing strategies are fundamentally route selection strategies built on accessible ad hoc routing protocols. This paper proposed a new Maximal Power Conserved And Energy Aware Routing (MPC-EAR ) topology for mobile ad hoc networks that enhances the network life span. Simulation results prove that the projected protocol has a higher performance other minimal energy usage, energy level aware and energy conserving routing protocols such as MTPR, MMECR and CMMECR.
Performance Analysis of Ultra Wideband Communication SystemEditor IJMTER
Ultra-Wideband (UWB) is a radio transmission scheme that uses extremely low power
pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages
over conventional continuous wave radio communications including potential support for high data
rates, robustness to multipath interference and fading. The paper covers Ultra Wide-Band
technology. General description, Challenges, various modulation schemes such as OOK, PAM,
PPM, and BPSK under specified Ultra Wide Band regimes: low Power spectral density, large
spreading ratio and a highly dispersive channel. The capacity and BER performance of a single user
ultra wideband communication is investigated for various modulation schemes and coded, uncoded
methods also simulated. Fading channel like Ricean and Rayleigh are compared. Channelized digital
receiver concept is discussed.
The four basic Radio Resource Management (RRM) measurements in Long Term Evolution (LTE) system
are Channel Quality Indicator (CQI), Reference Signal Received Power (RSRP), Reference Signal
Received Quality (RSRQ), and Carrier Received Signal Strength Indicator (RSSI). A measurement of channel quality represented by Signal to Interference plus Noise Ratio (SINR) is used for link adaptation along with packet scheduling, whereas RSRP and RSRQ are needed for making handover decision during intra-eUTRAN (evolved Universal Terrestrial Random Access Network) handover in LTE. In this paper,
some practical measurement results recorded from a live LTE network of Australia using a commercial measurement tool namely NEMO Handy are analysed to verify the possible relationships among SINR, RSRP, RSSI and RSRQ as well as to evaluate the effects of SNR on throughput. In addition, the intraeUTRAN handover events occurred during the test period within the test area are studied. The analysis
yields some useful information such as: if the SINR is good for a measurement slot, higher throughput is
achieved; RSRP and SNR are proportional to each other on average; and lesser is the difference between
RSSI and RSRP, better is the RSRQ – each of which is consistent with theory. All the measurement results
are evaluated using computer programs built on MATLAB platform.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
Equity mutual funds invest in companies that have potential for growth. The types of equity funds are blue chip funds, mid cap funds, diversified equity funds, dividend yield funds, equity index funds, sectoral funds and contra funds. Choose the right fund as per your needs.
MPC-EAR : Maximal Power Conserved And Energy Aware Routing in Ad hoc Networksijsrd.com
Power preservation in wireless ad hoc networks is a decisive factor as energy resources are inadequate at the electronic devices in use. Power-aware routing strategies are fundamentally route selection strategies built on accessible ad hoc routing protocols. This paper proposed a new Maximal Power Conserved And Energy Aware Routing (MPC-EAR ) topology for mobile ad hoc networks that enhances the network life span. Simulation results prove that the projected protocol has a higher performance other minimal energy usage, energy level aware and energy conserving routing protocols such as MTPR, MMECR and CMMECR.
Performance Analysis of Ultra Wideband Communication SystemEditor IJMTER
Ultra-Wideband (UWB) is a radio transmission scheme that uses extremely low power
pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages
over conventional continuous wave radio communications including potential support for high data
rates, robustness to multipath interference and fading. The paper covers Ultra Wide-Band
technology. General description, Challenges, various modulation schemes such as OOK, PAM,
PPM, and BPSK under specified Ultra Wide Band regimes: low Power spectral density, large
spreading ratio and a highly dispersive channel. The capacity and BER performance of a single user
ultra wideband communication is investigated for various modulation schemes and coded, uncoded
methods also simulated. Fading channel like Ricean and Rayleigh are compared. Channelized digital
receiver concept is discussed.
The four basic Radio Resource Management (RRM) measurements in Long Term Evolution (LTE) system
are Channel Quality Indicator (CQI), Reference Signal Received Power (RSRP), Reference Signal
Received Quality (RSRQ), and Carrier Received Signal Strength Indicator (RSSI). A measurement of channel quality represented by Signal to Interference plus Noise Ratio (SINR) is used for link adaptation along with packet scheduling, whereas RSRP and RSRQ are needed for making handover decision during intra-eUTRAN (evolved Universal Terrestrial Random Access Network) handover in LTE. In this paper,
some practical measurement results recorded from a live LTE network of Australia using a commercial measurement tool namely NEMO Handy are analysed to verify the possible relationships among SINR, RSRP, RSSI and RSRQ as well as to evaluate the effects of SNR on throughput. In addition, the intraeUTRAN handover events occurred during the test period within the test area are studied. The analysis
yields some useful information such as: if the SINR is good for a measurement slot, higher throughput is
achieved; RSRP and SNR are proportional to each other on average; and lesser is the difference between
RSSI and RSRP, better is the RSRQ – each of which is consistent with theory. All the measurement results
are evaluated using computer programs built on MATLAB platform.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
Equity mutual funds invest in companies that have potential for growth. The types of equity funds are blue chip funds, mid cap funds, diversified equity funds, dividend yield funds, equity index funds, sectoral funds and contra funds. Choose the right fund as per your needs.
4 ACOUSTIC brand gives a complete scope of expert sound items, for example, Active/Passive Line Array Speakers, Full Range Speakers, Sub woofers and Digital System Controllers. Each solid framework and also numerous gear parts from 4-Acoustic are outlined and built by experienced specialists in Germany before generation begins with our affirmed permit industrial facility in Asia.
Advanced antenna techniques and high order sectorization with novel network t...ijwmn
Mobile operators commonly use macro cells with trad
itional wide beam antennas for wider coverage in th
e
cell, but future capacity demands cannot be achieve
d by using them only. It is required to achieve max
imum
practical capacity from macro cells by employing hi
gher order sectorization and by utilizing all possi
ble
antenna solutions including smart antennas. This pa
per presents enhanced tessellation for 6-sector sit
es
and proposes novel layout for 12-sector sites. The
main target of this paper is to compare the perform
ance
of conventional wide beam antenna, switched beam sm
art antenna, adaptive beam antenna and different
network layouts in terms of offering better receive
d signal quality and user throughput. Splitting mac
ro cell
into smaller micro or pico cells can improve the ca
pacity of network, but this paper highlights the
importance of higher order sectorization and advanc
e antenna techniques to attain high Signal to
Interference plus Noise Ratio (SINR), along with im
proved network capacity. Monte Carlo simulations a
t
system level were done for Dual Cell High Speed Dow
nlink Packet Access (DC-HSDPA) technology with
multiple (five) users per Transmission Time Interva
l (TTI) at different Intersite Distance (ISD). The
obtained results validate and estimate the gain of
using smart antennas and higher order sectorization
with
proposed network layout.
Advanced antenna techniques and high order sectorization with novel network t...ijwmn
Mobile operators commonly use macro cells with traditional wide beam antennas for wider coverage in the
cell, but future capacity demands cannot be achieved by using them only. It is required to achieve maximum
practical capacity from macro cells by employing higher order sectorization and by utilizing all possible
antenna solutions including smart antennas. This paper presents enhanced tessellation for 6-sector sites
and proposes novel layout for 12-sector sites. The main target of this paper is to compare the performance
of conventional wide beam antenna, switched beam smart antenna, adaptive beam antenna and different
network layouts in terms of offering better received signal quality and user throughput. Splitting macro cell
into smaller micro or pico cells can improve the capacity of network, but this paper highlights the
importance of higher order sectorization and advance antenna techniques to attain high Signal to
Interference plus Noise Ratio (SINR), along with improved network capacity. Monte Carlo simulations at
system level were done for Dual Cell High Speed Downlink Packet Access (DC-HSDPA) technology with
multiple (five) users per Transmission Time Interval (TTI) at different Intersite Distance (ISD). The
obtained results validate and estimate the gain of using smart antennas and higher order sectorization with
proposed network layout.
Transmit power control and data rate enhancement in cognitive radio network u...IJECEIAES
Underutilized radio frequencies are the chief apprehension in advance radio communication. The radio recourses are sparse and costly and their efficient allocation has become a challenge. Cognitive radio networks are the ray of hope. Cognitive radio networks use dynamic spectrum access technique to opportunistically retrieve and share the licensed spectrum. The licensed users are called primary users and the users that opportunistically access the licensed spectrum all called secondary users. The proposed system is a feedback system that work on demand and supply concept, in which secondary receivers senses the vacant spectrum and shares the information with the secondary transmitters. The secondary transmitters adjust their transmission parameters of transmit power and data rate in such a way that date rate is maximized. Two methods of spectrum access using frequency division multiple access (FDMA) and Time division multiple access (TDMA) are discussed. Interference temperature limit and maximum achievable capacity are the constraints that regulate the entire technique. The aim of the technique is to control the transmitter power according to the data requirements of each secondary user and optimizing the resources like bandwidth, transmit power using machine learning and feed forward back propagation deep neural networks making full use of the network capacity without hampering the operation of primary network.
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.
Performance of cluster-based cognitive multihop networks under joint impact o...TELKOMNIKA JOURNAL
In this paper, we evaluate outage probability (OP) of a cluster-based multi-hop protocol operating
on an underlay cognitive radio (CR) mode. The primary network consists of multiple independent
transmit/receive pairs, and the primary transmitters seriously cause co-channel interference (CCI) to the
secondary receivers. To improve the outage performance for the secondary network under the joint impact
of the CCI and hardware imperfection, we employ the best relay selection at each hop. Moreover, the
destination is equipped with multiple antennas and uses the selection combining (SC) technique to
enhance the reliability of the data transmission at the last hop. For performance evaluation, we first derive
an exact formula of OP for the primary network which is used to calculate the transmit power of the
secondary transmitters. Next, an exact closed-form expression of the end-to-end OP for the secondary
network is derived over Rayleigh fading channels. We then perform Monte-Carlo simulations to validate
the derivations. The results present that the CCI caused by the primary operations significantly impacts on
the outage performance of the secondary network.
Downlink beamforming and admissin control for spectrum sharing cognitive radi...acijjournal
We investigate the
problem of multiuser downlink beam
-
forming and admission control considering a
scenario where licensed, or primary, users and cognitive radios, or secondary users, are transmittin
g
concurrently over the same band. The primary users share a common receiver
and the interference on this
receiver from secondary users should be strictly limited to a certain level. Each secondary link is
assumed
to have a minimum quality of service (QoS) requirement that should be satisfied together with the
interference limit co
nstraint, otherwise the secondary link is not admitted. Under those constraints,
downlink beam
-
forming and admission control for secondary users are investigated for two main
optimization objectives. First, we maximize the number of admitted secondary link
s. Second, we maximize
the sum throughput of the admitted secondary links. our main design objective is to minimize the tra
nsmit
power of the SU
-
transmitter while simultaneously targeting a lower
-
bound on the received signal
-
to
-
interference
-
plus
-
noise
-
rati
o(SINR) for the SU’s and imposing on upper limit on the interference power(IP)
at the PUs.
Throughput Maximization of Cognitive Radio Multi Relay Network with Interfere...IJECEIAES
In this paper, an Orthogonal Frequency Division Multiplexing (OFDM) based cognitive multi relay network is investigated to maximize the transmission rate of the cognitive radio (CR) with enhanced fairness among CR users with interference to the primary users (PUs) being managed below a certain threshold level. In order to improve the transmission rate of the CR, optimization of the subcarrier pairing and power allocation is to be carried out simultaneously. Firstly joint optimization problem is formulated and Composite Genetic and Ordered Subcarrier Pairing (CGOSP) algorithm is proposed to solve the problem. The motivation behind merging genetic and OSP algorithm is to reduce the complexity of Genetic Algorithm (GA). Further, to have a fair allocation of resources among CR users, the Round Robin allocation method is adopted so as to allocate subcarrier pairs to relays efficiently. The degree of fairness of the system is calculated using Jain‟s Fairness Index (JFI). Simulation results demonstrate the significant improvement in transmission rate of the CR, low computational complexity and enhanced fairness.
Implementation of Vacate on Demand Algorithm in Various Spectrum Sensing Netw...IJERA Editor
In present days the wireless communications are widely increases because of this reason spectrum utilization can be rapidly increased.For efficient usage of spectrum we can implement the Vacate on demand algorithm in different networks. CR users also need to sense the spectrum and vacate the channel upon the detection of the PU‟s presence to protectPUs from harmful interference. To achieve these fundamental CR functions, CR users usually coordinate with each other by using a common medium for control message exchange ensuring a priority of PUs over CR users. This paper presents the Vacate on Demand (VD) algorithm which enables dynamic spectrum access and ensures to vacate the assigned channel in case of PU activity and move the CR user to some other vacant channel to make spectrum available to PUs as well as to CR users. The basic idea is to use a ranking table of the available channels based on the PU activity detected on each channel. To improve the spectrum efficiency we can implement the Vacate on demand algorithm in MANET Network.
Digital Beamforming for Simultaneous Power and Information Transmission in Wi...idescitation
This paper proposes a Beamforming algorithm for
simultaneous transmission of information and power in multi-
antenna linear array system. Here we considered three node
system in which transmitter and receiver are largely separated
from each other whereas energy harvesting circuit is co-
located with the information receiver i.e. encounters the same
channel from the transmitter. Our primary motto is to
maximize the energy harvested by the harvester circuit, at
the same time maintaining the information rate above a
certain threshold level. Firstly, we used an algorithm to steer
the antenna beam in a desired direction. Secondly, we
combined this algorithm with another algorithm that
maximizes the harvested energy. The hybrid algorithm
produces an improvement in the result in terms of received
signal level and side-lobe level. Finally, simulation results
are presented to justify the effectiveness of the proposed
algorithm.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Channel characterization and modulation schemes of ultra wideband systemsijmnct
Channel measurements are generally the basis for channel models. Strictly speaking, channel models do
not exclusively require measurements, but it is a fact that all standardized models are derived from
measurements. This licentiate paper is focused on the characterization of ultra-wideband wireless channels.
The paper presents the characterization of ultra wide band system with their benefits and drawbacks within
the telecommunication industry. Furthermore with the advantages of Ultra wideband several modulation
techniques for UWB are discussed in this paper.
Transferring quantum information through theijngnjournal
Transmission of information in the form of qubits much faster than the speed of light is the important
aspects of quantum information theory. Quantum information processing exploits the quantum nature of
information that needs to be stored, encoded, transmit, receive and decode the information in the form of
qubits. Bosonic channels appear to be very attractive for the physical implementation of quantum
communication. This paper does the study of quantum channels and how best it can be implemented with
the existing infrastructure that is the classical communication. Multiple access to the quantum network is
the requirement where multiple users want to transmit their quantum information simultaneously without
interfering with each others.
Transferring Quantum Information through the Quantum Channel using Synchronou...josephjonse
Transmission of information in the form of qubits much faster than the speed of light is the important aspects of quantum information theory. Quantum information processing exploits the quantum nature of information that needs to be stored, encoded, transmit, receive and decode the information in the form of qubits. Bosonic channels appear to be very attractive for the physical implementation of quantum communication. This paper does the study of quantum channels and how best it can be implemented with the existing infrastructure that is the classical communication. Multiple access to the quantum network is the requirement where multiple users want to transmit their quantum information simultaneously without interfering with each others.
Throughput maximization in multiuser wireless powered communication network b...paperpublications3
Abstract: WPCN (wireless powered communication network) is the newly emerging network in which an access point called hybrid access point (HP) broadcast energy in the downlink and in the upper link wireless information transfer take place from sensors to hybrid access point. A protocol called “harvest-thentransmit” protocol is proposed where all users first harvest the wireless energy from the H-AP, in the downlink (DL) and then send their independent information to the HAP in the uplink (UL) by time-division-multiple-access (TDMA). A set of relay nodes used in the network enhances the over all throughput than sum throughput and common through hput. More energy efficient network can be got by using relay nodes. Simulation result showing the priority of the network that using relay nodes than other ordinary wireless sensor networks.
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Ergodic capacity analysis for underlay cognitive radio system
1. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
DOI : 10.5121/ijmnct.2014.4602 13
ERGODIC CAPACITY ANALYSIS FOR UNDERLAY
COGNITIVE RADIO SYSTEM
Indu Bala1
, Manjit Singh Bhamrah2
and Ghanshyam Singh3
1,2
ECE Department, Punjabi University, Patiala, India
3
ECE Department,JUIT, Solan, India
ABSTRACT
Cognitive radio technology has been proposed as a viable solution to the spectrum scarcity problem faced
by world today. The technology allows opportunistic spectrum access to the licensed frequency band by
unlicensed user without causing any harmful interference to the licensed primary user. In this paper,
ergodic channel capacity is investigated for underlay spectrum sharing system under maximum and
received power constraint at licensed primary receiver. The time varying discrete time fading channels are
assumed to undergo Rayleigh flat fading environment. Numerical simulations have been done to support
theoretical results.
KEYWORDS
Cognitive Radio, Channel State Information, Rayleigh Fading, Ergodic Capacity.
1.INTRODUCTION
Since, wireless products have become an integral part of modern lifestyle; the 21st century has
witnessed the rapid deployment of wireless devices and applications in market. All these
bandwidth hungry applications have increased the demand of electromagnetic spectrum.
Traditionally, spectrum allocation policy is very inflexible in a sense that frequency band are
exclusively licensed to the user for long term access with restriction on maximum transmission
power to shield systems from mutual interference all the time. Since, most of the spectrum is
already assigned, with the emergence of new wireless applications and constant need of mobile
internet access, the demand for the wireless spectrum has increased manifolds and it is becoming
extremely difficult to find vacant frequency band to deploy new wireless applications or to
enhance the existing ones[1-2].
Cognitive radio technology has been proposed as a viable solution to the spectrum scarcity
problem faced by world today. The technology allows opportunistic spectrum access to the
licensed frequency band by unlicensed user without causing any harmful interference to the
licensed primary user. The novel technology aims to have adaptive and flexible communication
equipments designed in a way to monitor spectrum variations constantly over a wide range of
frequencies and to adapt transmission parameters such as carrier frequency, bandwidth, modulation
scheme, data rate and transmission power etc. this motivates the further investigation of cognitive
radio network as a mean to mitigate spectrum scarcity problem. As a matter of fact, it has become
hot topic of research and attracting researchers and academicians all over the world to propose new
communication protocols to exploit the full capability of cognitive radios and to redefine the
fundamental limits of the channel capacity for cognitive radios.
2. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
14
In this regard, a communication protocol is proposed in [3] to determine the channel conditions
and to adapt its transmission signal to occupy the vacant band. Later, the approach is generalized to
allow primary and secondary users to transmit simultaneously at the same time or at same
frequency over additive white Gaussian noise (AWGN) channel and derived capacity bound for
the same [4]. Most of the work previously has considered maximum transmit power constraint to
limit the fundamental capacity of cognitive radio network, Received power constraint at primary
receiver was firstly considered in [5] to explore the capacity of spectrum sharing channels. Author
has used received power constraint on primary receiver. Later, ergodic capacity for point to point
configuration is investigated either for maximum transmit power or average received power
constraint at primary user receiver. It has been shown in [5] that significant capacity gain can be
achieved if channel is varying due to fading. The same channel can be exploited by secondary user
by transmitting opportunistically at higher power levels. This is in contrast to the systems with
maximum transmission power constraint, where capacity degrades significantly because of fading.
In this paper, we have investigated the usefulness of various channel capacities, namely Ergodic
(Shannon) capacity, where it is assumed that the channel transitions over all the fading states, for
underlay cognitive radio system. The underlay cognitive radio system is the one in which the
secondary cognitive user adapts its transmission based on the knowledge about channel gains
between secondary and primary user. The maximum transmission power and averaged received
power constraint at primary user’s receiver jointly to estimate these channel capacities under
Rayleigh fading environment.
2. SYSTEM AND CHANNEL MODEL
In this paper, we have considered underlay spectrum sharing system in which a secondary user is
allowed to use the licensed frequency band along with the licensed primary user, as long as the
amount of interference inflicted at primary user is within predefined constraints on average and
maximum values of transmission power. The spectrum sharing scenario and system model is
shown in Fig. 1. It has been assumed that perfect channel state information (CSI) is known ahead
of time to the secondary transmitter and receiver in advance.
Fig. 1: Spectrum Sharing System Model
The time varying discrete-time fading channels are assumed to undergo Rayleigh flat fading, and
the received signal power yୱሾnሿ at the secondary receiver depends on the transmitted signal power
xୱሾnሿ according to
yୱሾnሿ = hୱሾnሿxୱሾnሿ + Nୱ (1)
3. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
15
Where n is time index, hୱሾnሿ is the channel power gain between the secondary transmitter and
receiver, and Nୱሾnሿ represents AWGN. The power gain between the transmitter of secondary user
and receiver of the primary user is hୱ୮ሾnሿ. Both channel power gains hୱሾnሿ and hୱ୮ሾnሿ are
independent and identically distributed (i.i.d.) exponentially distributed with unit mean.
Furthermore, channel gains are assumed to be independent from the noise. The noise power
spectral density and the signal bandwidth are represented by N and ܤrespectively. Given that
secondary transmission will not degrade signal quality at the primary receiver, constraints can be
imposed on the received power at primary receiver. If P୫ୟ୶୧୫୳୫ is the maximum received power
constraint and Pୟ୴ is the average power constraint, the corresponding constraint may be define as
P൫hୱ, hୱ୮൯hୱ୮ ≤ P୫ୟ୶୧୫୳୫, ∀ hୱ, hୱ୮ (2)
ε୦౩୦౩౦
൛P൫hୱ, hୱ୮൯hୱ୮ൟ ≤ Pୟ୴ (3)
where P൫hୱ, hୱ୮൯ represents the transmit power, and ε୦౩,୦౩౦
represents the expectation over joint
probability density function (PDF) of hୱ and hୱ୮.
3. ERGODIC CAPACITY
In this section, the ergodic capacity for underlay spectrum sharing system is investigated for
Rayleigh fading channel under received power constraint. The ergodic capacity is defined as
maximum average rate with minimum probability of error under constrained transmission power.
This is a useful performance metric for the systems in which the delay is not a constraint.
Considering the average transmission power a constraint, system capacity under fading with full
knowledge of CSI at secondary transmitter and receiver is derived in [6]. The closed form
expression for the channel capacity of above system under Rayleigh fading is derived in [7].
Maximum and average power constraint on secondary transmission power was firstly considered
in [8] for Gaussian channel and results were extended for quadrature Gaussian channel in [9]. In
[10], the capacity of fading channel for maximum and average transmission power constraint was
derived using multiplexed Gaussian codebook for optimum power allocation in time.
On contrary to the above, the constraint on received power is considered in [5] and the capacity of
AWGN channels for single and multiple users is estimated. It was shown that the capacity of
point- to- point AWGN channel with received power constraint is equal to the capacity of the
channel under appropriately ranged transmit power constraint. The result, however, does not hold
for fading channels. The ergodic capacity with average and maximum power constraint is given
in [11] and optimal power allocation scheme has also been presented. The notations used in
power calculations are given in Table 1.
S. No. Symbol Parameter
1 ℎ௦ Channel gain between secondary Tx and Rx
2 ℎ Channel gain between Primary Tx and Rx
3 ℎ௦ Channel gain between Tx of SU and Rx of PU
4 ܲ௫௨ Maximum allowed SU transmission power
5 ܲ௩ Average received power at Rx of PU
6 ܥ Ergodic Channel Capacity
7 ܰ Noise Variance
8 ܤ Channel Bandwidth
9 ߣ Cut off Tthreshold value
10 ߛ Signal to Noise Ratio
4. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
16
In this section, received power constraints are being investigated at a primary receiver under
fading environment. These are the maximum and average received power constraints as given in
(2) and (3) respectively. By using an approach similar to that used in [8], the channel capacity can
be shown to be achieved through optimum utilization of the added power over time such that
received power constraints are met. Therefore, the ergodic channel capacity in this case becomes
an optimization problem and will be given as [12]:
Cୣ୰
B
= max
൫୦౩,୦౩౦൯ஹ
ε୦౩,୦౩౦
ቊlog ቆ1 +
P൫hୱ, hୱ୮൯hୱ
NB
ቇቋ
s. t. ε୦౩,୦౩౦
൛P൫hୱ, hୱ୮൯hୱ୮ൟ ≤ Pୟ୴,
P൫hୱ, hୱ୮൯hୱ୮ ≤ P୫ୟ୶୧୫୳୫, ∀ hୱ, hୱ୮ (4)
The optimization problem in (4), without any constraint on maximum received power, is
considered in [13] and solved by using Lagrangian optimization. Considering the problem under
both power constraints and adopting a similar approach, the solution for (4) can be obtained using
Lagrangian optimization by defining
L൫P൫hୱ, hୱ୮൯, λ൯ = ε୦౩,୦౩౦
൜log ൬1 +
൫୦౩,୦౩౦൯୦౩
బ
൰ൠ − λ ቀε୦౩,୦౩౦
൛P൫hୱ, hୱ୮൯hୱ୮ൟ − Pୟ୴ቁ (5)
Musavian and Aissa [12] have provided a closed form expression for ergodic capacity of a system
under power constraints as follows:
େ౨
= −log ቀ1 −
ౣ౮ౣ౫ౣ
బା ஓబ
ቁ +
ౣ౮ౣ౫ౣ
ౣ౮ౣ౫ౣିబ
log ቆ
ౣ౮ౣ౫ౣ
బஓబ
ሺNB + γ − P୫ୟ୶୧୫୳୫ሻቇ (6)
where, λ =
బ
ஓబ
, represents the optimal threshold value for which the transmission is suspended.
4. SIMULATION RESULTS & DISCUSSION
Figure 1 and Fig. 2 are showing the ergodic capacity under Rayleigh fading channel and the
optimum cut off threshold associated with this capacity respectively. Impact of the maximum
received power on ergodic capacity is shown in fig.1 by plotting ergodic capacity in nats/s/Hz
verses Pୟ୴ for different values of ρ =
ౣ౮ౣ౫ౣ
౬ౝ
. For the comparison purpose, results are
compared with a case when only one constraint on either maximum or average received power is
considered. It is clear from fig. 1 that ergodic channel capacity degrades with decrease in average
received power when maximum received power constraint is applied on the top of the average
received power constraint. With an increase in the parameter ρ ergodic capacity start converging
towards a case of no maximum received power constraint.
5. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
17
Fig.1: Ergodic capacity under maximum and received power constraint for different ߩ.
Fig. 2: Optimum cut-off threshold for different values of ρ.
Fig. 2 is showing the behaviour of optimum cut off threshold λ under which transmission is
suspended. It can be observed from the fig. 2 that optimum cutoff threshold value increases with
an increase of the constraint on maximum received power at primary receiver. Moreover, for given
constraint value, optimum threshold increases with decrease in the value of average received
power at primary user’s receiver.
6. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
18
Fig.3: Ergodic Capacity under maximum and received power constraint for different ܲ௫௨.
Fig. 3 is showing the behaviour of ergodic capacity with respect to the ܲ௩ for the different
values of maximum received power at primary receiver. It is clear that for the smaller values of
average power, impact of maximum received power is negligible. For the given maximum power
constraint, ergodic capacity increase with an increase in average received power and attain
maximum value equals to the ܲ௫௨ and then start decreasing.
5. CONCLUSION
The underlay spectrum sharing system is investigated for the ergodic capacity under maximum
and received power constraint at licensed primary receiver for Rayleigh fading environment. It is
shown that maximum received power constraint has almost negligible impact on ergodic capacity
of channel when applied on the top of the average received power constraint. For the smaller
values of average power, impact of maximum received power is negligible and ergodic capacity
increases with an increase in average received power and attain maximum value equals to the
ܲ௫௨ and then start decreasing.
REFERENCES
[1] Vanita Rana, Indu Bala, Neelu Jain, (2014) “Resource Allocation Models for Cognitive Radio
Networks: A Study”, International. Journal of Computer Applications, vol. 91, No. 12, pp. 51-55.
[2] Indu Bala, Manjit Singh Bhamrah, Ghanshyam Singh, (2014) “Analytical Modelling of Ad Hoc
Cognitive Radio Environment for Optimum Power Control”, International. Journal of Computer
Applications, vol. 92, No. 7, pp. 19-22.
[3] W. D. Horne, (2003) “Adaptive spectrum access: using the full spectrum space,” in the Proceedings
of Telecommunication Policy Research Conference (TPRC).
[4] N. Devroye, P. Mitran, and V. Tarokh, (2006) “Achievable rates in cognitive radio channels,” IEEE
Transactions on Information Theory, vol. 52, no. 5, pp. 1813–1827.
[5] M. Gastpar, (2004) “On capacity under received-signal constraints,” in the Proceedings of 42nd
Annual Allerton Conference on Communication Control and Computing.
[6] A. J. Goldsmith and P. Varaiya,(1997) “Capacity of fading channels with channel side information,”
IEEE Transaction on Information Theory, vol. 43, no. 6,pp. 1986–1992.
[7] M.-S. Alouini and A. J. Goldsmith,(1999) “Capacity of Rayleigh fading channels under different
adaptive transmission and diversity-combining techniques,” IEEE Transactions on Vehicular
Technology, vol. 48, no. 4, pp. 1165–1181.
7. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.6,December 2014
19
[8] J. G. Smith,(1971) “The information capacity of amplitude- and variance constrained scalar Gaussian
channels,” Information and Control, vol. 18,no. 3, pp. 203–219.
[9] S. Shamai (Shitz) and I. Bar-David,(1995) “The capacity of average and maximum-power-limited
quadrature Gaussian channels,” IEEE Transaction on Information Theory, vol. 41, no. 4, pp. 1060–
1071.
[10] M. A. Khojastepour and B. Aazhang, (2004) “The capacity of average and maximum power
constrained fading channels with channel side information,” in the Proceedings of IEEE Wireless
Communication and Networking Conference (WCNC), pp. 77–82.
[11] A. Ghasemi and E. S. Sousa,(2006) “Capacity of fading channels Under spectrum-sharing
constraints,” in the proceedings of IEEE International Conference of Communication (ICC), pp.
4373–4378.
[12] Leila Musavian and Sonia Aıssa,(2009) “Capacity and Power Allocation for Spectrum-Sharing
Communications in Fading Channels ”, IEEE Transactions On Wireless Communications, Vol. 8, No.
1,pp. 148-156.