This document summarizes a research paper on statistical multipath signal detection in CDMA for ad hoc networks. The paper presents simulation results of transmitting a signal through 5 different Rayleigh fading channels and selecting the signal with the highest SNR. The selected signal is then transmitted over an ad hoc network using a shortest path routing algorithm. Key aspects covered include: Rayleigh fading modeling, CDMA, OFDM, theoretical and simulated BER comparisons of BPSK over Rayleigh and AWGN channels, implementation of signal transmission over 5 channels in MATLAB, and use of the highest quality signal for transmission in an ad hoc network.
1) The document discusses channel estimation techniques for 4G wireless networks using OFDM modulation.
2) Channel estimation is important for coherent detection and diversity techniques in wireless systems, which have time-varying channels. Accurate channel estimation allows techniques like maximal ratio combining.
3) OFDM divides the channel into multiple sub-carriers to combat multipath fading and make channel equalization easier compared to single carrier systems. Channel estimation is needed to characterize the time-varying frequency response of the wireless channel.
This document discusses multi-radio hybrid wireless-optical broadband access networks (WOBANs). It describes how WOBANs combine optical and wireless networks, with fiber providing long-distance connectivity to the central office and wireless providing local access. Equipping mesh routers in the wireless front-end with multiple radios tuned to non-overlapping channels can improve network throughput by allowing more simultaneous transmissions. However, properly assigning channels to radios is challenging. The document proposes addressing integrated routing and channel assignment in multi-radio WOBANs to evaluate how throughput can be increased by using multiple radios per router and optimally distributing radios across the network.
Modelling and QoS-Achieving Solution in full-duplex Cellular SystemsIJCNCJournal
The global bandwidth scarcity and the ever-growing demand for fast wireless services have motivated the quest for new techniques that enhance the spectral efficiency (SE) of wireless systems. Most conventional SE increasing methods (e.g., adaptive modulation and coding) have already been exhausted. Single-channel full-duplex (SCFD) communication is a new attractive approach in which each node may simultaneously receive and transmit over the same frequency channel, and thus, it has the potential to double the current SE figures. In this paper, we derive a model for the signal-to-interference-plus-noise ratio (SINR) in a SCFD-based cellular system with imperfect self-interference cancellation. Furthermore, given a set of uplink and downlink quality of service requirements, we answer the following two fundamental questions. First, is this set achievable in the SCFD-based cellular system? Second, if the given set is achievable, what is the optimal achieving policy? To that end, we provide a unified model for the SCFD-based cellular system, and give insights in the matrix of interference channel gains. Simulation results suggest that depending on the locations of the users, a combination of full-duplex and half-duplex modes over the whole network is more favourable policy
Propagation measurements and models for wireless channelsNguyen Minh Thu
This document discusses wireless propagation measurements and channel models. It begins by describing the importance of understanding propagation for wireless communication systems and outlines different modeling approaches. It then discusses key propagation parameters like path loss, multipath delay spread, and measurements used to characterize wireless channels. Specific propagation mechanisms like reflection, diffraction and scattering are also covered. The document concludes by examining outdoor and indoor propagation environments and considerations for modeling different scenarios.
1) The document discusses smart antennas for WiMAX radio systems. Smart antennas can sense their environment and adjust their gain in different directions, increasing traffic capacity and quality of service.
2) Two main types of smart antenna configurations are discussed: switched beam arrays and adaptive arrays. Switched beam arrays form fixed beams toward different directions, while adaptive arrays use signal processing to dynamically steer beams toward desired users and place nulls toward interferers.
3) The MUSIC algorithm for direction of arrival estimation is described. MUSIC exploits the noise eigenvector subspace to provide unbiased estimates of the number and angles of incoming signals. It assumes uncorrelated noise and may be used to estimate directions of arrival to implement adaptive
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
This document provides an outline for a lecture on data communication and computer networks. It covers networking fundamentals and each layer of the OSI model, including the physical layer, data link layer, network layer, transport layer, and application layer. For the physical layer, it discusses different transmission media such as twisted pair, coaxial cable, optical fiber, and wireless. It provides details on technologies like Ethernet, DSL, and fiber optic cable. The data link layer section covers terminology and the role of the link layer in transferring data between adjacent nodes.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
1) The document discusses channel estimation techniques for 4G wireless networks using OFDM modulation.
2) Channel estimation is important for coherent detection and diversity techniques in wireless systems, which have time-varying channels. Accurate channel estimation allows techniques like maximal ratio combining.
3) OFDM divides the channel into multiple sub-carriers to combat multipath fading and make channel equalization easier compared to single carrier systems. Channel estimation is needed to characterize the time-varying frequency response of the wireless channel.
This document discusses multi-radio hybrid wireless-optical broadband access networks (WOBANs). It describes how WOBANs combine optical and wireless networks, with fiber providing long-distance connectivity to the central office and wireless providing local access. Equipping mesh routers in the wireless front-end with multiple radios tuned to non-overlapping channels can improve network throughput by allowing more simultaneous transmissions. However, properly assigning channels to radios is challenging. The document proposes addressing integrated routing and channel assignment in multi-radio WOBANs to evaluate how throughput can be increased by using multiple radios per router and optimally distributing radios across the network.
Modelling and QoS-Achieving Solution in full-duplex Cellular SystemsIJCNCJournal
The global bandwidth scarcity and the ever-growing demand for fast wireless services have motivated the quest for new techniques that enhance the spectral efficiency (SE) of wireless systems. Most conventional SE increasing methods (e.g., adaptive modulation and coding) have already been exhausted. Single-channel full-duplex (SCFD) communication is a new attractive approach in which each node may simultaneously receive and transmit over the same frequency channel, and thus, it has the potential to double the current SE figures. In this paper, we derive a model for the signal-to-interference-plus-noise ratio (SINR) in a SCFD-based cellular system with imperfect self-interference cancellation. Furthermore, given a set of uplink and downlink quality of service requirements, we answer the following two fundamental questions. First, is this set achievable in the SCFD-based cellular system? Second, if the given set is achievable, what is the optimal achieving policy? To that end, we provide a unified model for the SCFD-based cellular system, and give insights in the matrix of interference channel gains. Simulation results suggest that depending on the locations of the users, a combination of full-duplex and half-duplex modes over the whole network is more favourable policy
Propagation measurements and models for wireless channelsNguyen Minh Thu
This document discusses wireless propagation measurements and channel models. It begins by describing the importance of understanding propagation for wireless communication systems and outlines different modeling approaches. It then discusses key propagation parameters like path loss, multipath delay spread, and measurements used to characterize wireless channels. Specific propagation mechanisms like reflection, diffraction and scattering are also covered. The document concludes by examining outdoor and indoor propagation environments and considerations for modeling different scenarios.
1) The document discusses smart antennas for WiMAX radio systems. Smart antennas can sense their environment and adjust their gain in different directions, increasing traffic capacity and quality of service.
2) Two main types of smart antenna configurations are discussed: switched beam arrays and adaptive arrays. Switched beam arrays form fixed beams toward different directions, while adaptive arrays use signal processing to dynamically steer beams toward desired users and place nulls toward interferers.
3) The MUSIC algorithm for direction of arrival estimation is described. MUSIC exploits the noise eigenvector subspace to provide unbiased estimates of the number and angles of incoming signals. It assumes uncorrelated noise and may be used to estimate directions of arrival to implement adaptive
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
This document provides an outline for a lecture on data communication and computer networks. It covers networking fundamentals and each layer of the OSI model, including the physical layer, data link layer, network layer, transport layer, and application layer. For the physical layer, it discusses different transmission media such as twisted pair, coaxial cable, optical fiber, and wireless. It provides details on technologies like Ethernet, DSL, and fiber optic cable. The data link layer section covers terminology and the role of the link layer in transferring data between adjacent nodes.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
This document analyzes the effects of shadowing and fading on the performance of ad hoc routing protocols in mobile ad hoc networks (MANETs). It simulates the performance of three routing protocols - Location-Aided Routing (LAR), Routing Information Protocol (RIP), and LANMAR - under different shadowing and fading conditions using the QualNet simulator. The simulation evaluates the protocols based on application layer metrics like end-to-end delay, jitter, throughput, and packet delivery ratio, as well as physical layer metrics like power consumption and battery usage. The results show the impact of realistic channel models like shadowing and fading on routing protocol performance in MANETs.
The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In...inventionjournals
This is a study conducted in a laboratory at the university as a simulation to see the effect of new fiber PMD for different distances. This is done to compare the performance of the digital system with optical fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation is a standard single mode fiber (SSMF).
This document proposes and analyzes a model for planning hybrid wireless-optical broadband access networks (WOBANs). A WOBAN combines the reliability of fiber optic networks with the flexibility of wireless networks. The document presents a primal model for optimally placing base stations and optical network units in a WOBAN. It develops constraints for user assignment, capacity, interference and develops a Lagrangean relaxation approach and primal algorithm to obtain upper and lower bounds for the solution to the primal model. Simulation results are used to compare the primal model to a cellular heuristic placement approach.
This document discusses enhancing the capacity of the wireless portion of a hybrid wireless-optical broadband access network (WOBAN) through the strategic placement of additional radios at bottleneck nodes. Deploying multiple radios at every node improves performance but increases costs. The document proposes formulating the problem of optimally placing a limited number of additional radios as an integer linear program to maximize performance while minimizing costs. Prior work on routing, capacity assignment, and radio placement in wireless mesh networks is reviewed. The impact of deploying multiple radios only at overloaded bottleneck nodes is studied through numerical examples.
Joint Interference Coordination and Spatial Resource ReuseIJMTST Journal
Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. Deploying relay nodes is foreseen a cost-efficient solution to combat the severe propagation loss at cell edge. However, relay cell coverage is limited by the low transmit power, limited antenna capabilities and wireless backhaul link bottleneck which may lead to load imbalances and hence low resource utilization efficiency. Further challenges in relay deployments are attributed to increased interference levels in the network compared with macro cell-only deployments, causing degradation of the user throughput. In this context, relay cell coverage expansion and interference coordination techniques are expected to improve the performance of relay deployments. In this study, we analyze the impact of the additional interference due to the relay node transmissions. Jointly with our previous study on cell expansion, spatial resource reuse from the graph-theoretical perspective. Next, our focus shifts to developing a simple but efficient radio resource management algorithm which enables the spatial resource reuse, the pricing- based radio resource management (PRRM) strategy. The PRRM performs spatial reuse for interference-free users operating in the high signal-to-interference-and-noise ratio (SINR) region, while guaranteeing the signal quality of interference-susceptible users usually located near the coverage boundary. By applying the PRRM, we evaluate the potential benefits of the spatial resource reuse.
EFFICIENT REAL-TIME VIDEO TRANSMISSION IN WIRELESS MESH NETWORK IJORCS
This document summarizes a research paper on efficient real-time video transmission in wireless mesh networks. It begins with an introduction to wireless mesh networks and their benefits. It then discusses some key challenges for real-time video transmission, including unpredictable delays, packet loss, and delay jitter due to the error-prone nature of wireless links. The paper proposes a model to provide high-capacity data transfer with reduced delay for real-time video. It simulates this model using OPNET and achieves higher throughput results. Node models for the video server, receiver, access point, and FTP client/server are also described.
Energy Efficient Resource Allocation and Relay Selection Schemes for D2D Comm...ijtsrd
Device to Device D2D communication is a wireless peer to peer service, that allows direct communication to discharge hub input by binding wireless broadcasting amongst devices, as a vital technology module for next generation cellular communication system. Mobile devices limited battery power is a barricade for harnessing the performance of cellular communication systems. High data rate Device to Device communication is requisite to boost the crescent traffic requirement of apparent applications. In this paper suggest a centralized relay selection and power allocation process to state a multi objective optimization trouble to clearance the commutation in between total transmit power and system throughput. The proposed framework, suggest lowest perplexity modulation and demodulation procedure by route discovery for Generalized frequency division multiplexing systems. The proposed diplomacy deed the peculiar framework of the modulation matrix to depress the computational rate in the absence of meet with any performance loss distress. Centralized algorithm to discover the outcome in polynomial time. Proposed algorithms markedly minimize the total transmit power and enhance the system throughput. Surya S M | Prof. K. Kalai Selvi "Energy-Efficient Resource Allocation and Relay Selection Schemes for D2D Communications in 5G Wireless Networks" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-3 , April 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30413.pdf Paper Url :https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/30413/energyefficient-resource-allocation-and-relay-selection-schemes-for-d2d-communications-in-5g-wireless-networks/surya-s-m
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
Introductory Approach on Ad-hoc Networks and its Paradigms IJORCS
This document provides an introductory overview of ad-hoc networks, including:
1) A definition of ad-hoc networks as decentralized wireless networks that self-configure without preexisting infrastructure;
2) A discussion of mobile ad-hoc networks (MANETs) and wireless sensor networks as examples of ad-hoc networks;
3) An overview of challenges in providing quality of service in ad-hoc networks given their dynamic topology.
This document summarizes research on improving the capacity of cellular systems using fractional frequency reuse (FFR). It discusses how frequency reuse is used to increase the number of users that can be served but causes interference, particularly for cell edge users. Fractional frequency reuse is proposed to solve this problem by allocating different frequency sets to cell center and edge users to reduce interference. The document also reviews different types of interference (co-channel and adjacent channel) and how power control can help reduce interference in cellular systems.
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.
Wideband Sensing for Cognitive Radio Systems in Heterogeneous Next Generation...CSCJournals
Mobile Next Generation Network (MNGN) is characterized as heterogeneous network where variety of access technologies are meant to coexist. Decisions on choosing an air interface that meets a particular need at a particular time will be shifted from the network’s side to (a more intelligent) user’s side. On top of that network operators and regularities have come to the realization that assigned spectrum bands are not utilized as they should be. Cognitive radio stands out as a candidate technology to address many emerging issues in MNGN such as capacity, quality of service and spectral efficiency. As a transmission strategy, cognitive radio systems depend greatly on sensing the radio environment. In this paper, we present a novel approach for interference characterization in cognitive radio networks based on wideband chirp signal. The results presented show that improved sensing accuracy is maintained at tolerable system complexity.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document summarizes performance evaluation in wireless networks. It discusses how mobile ad hoc networks are self-configuring networks of wireless devices that can communicate directly or through intermediate nodes. It outlines some key characteristics of MANETs including dynamic topology, bandwidth constraints, and energy constraints. It also discusses different routing approaches for MANETs such as proactive (table-driven) and reactive (on-demand) protocols. Finally, it provides an overview of the operating principles of MANETs through an example network topology.
This document discusses dispersion compensation techniques for optical code division multiple access (OCDMA) systems using dispersion compensation fiber (DCF) and fiber gratings. It compares the performance of an 8-user OCDMA system using DCF versus fiber gratings. The results show that DCF more effectively compensates for dispersion, as evidenced by a lower bit error rate and higher Q factor, making it a better dispersion compensation method for OCDMA systems compared to fiber gratings.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Different Issues and Survey of Proposed Solutions in TCP over Wireless Enviro...Ranjeet Bidwe
This document discusses issues with using TCP in wireless networks and proposed solutions. The main issues are higher bit error rates, lower bandwidth, mobility, and longer round trip times in wireless networks compared to wired networks. TCP was designed for wired networks and assumes packet loss is always due to congestion, but in wireless networks loss can occur for other reasons like bit errors, handoffs, or disconnections. This wrong assumption causes TCP to reduce its window size unnecessarily, degrading performance. The document surveys proposed solutions like Snoop to cache packets at base stations to hide losses from the sender, and Explicit Congestion Notification to signal congestion before queue overflows.
This paper analyzes the performance of three routing protocols (AODV, DSDV, OLSR) for mobile WiMAX networks using the random direction mobility model in NS3 simulator. The protocols are evaluated based on routing overhead, packet delivery ratio, throughput, end-to-end delay, and packet loss. The results found that OLSR protocol outperformed AODV and DSDV, with lower routing overhead and higher packet delivery ratio, demonstrating improved efficiency for WiMAX networks.
The document discusses media access control (MAC) strategies for shared transmission media. It begins by explaining the need for MAC in cases where multiple users share a common channel. It then discusses different MAC approaches such as scheduling versus random access, centralized versus distributed control, and examples including TDMA, slotted ALOHA, and CSMA/CD. Key MAC influences like distance between stations, throughput requirements, traffic patterns are also covered. Specific MAC protocols discussed include those used in ISDN, Ethernet, GSM, and wireless networks.
QuScient is a profitable, debt-free company that provides outsourced higher education services from its 360-seat facility in Chennai, India and office in Phoenix, AZ. It offers a range of products and solutions for lead generation, enrollment, academic records, advising, and retention. Key services include a 170-seat call center, application processing, transcript evaluation, technical support, recruitment and monitoring of adjunct faculty, and the ProRetention student relationship management suite.
The document discusses the triangular slave trade that occurred between Europe, Africa, and the Americas in the 18th century. It describes how Great Britain financially benefited from transporting slaves from Africa to work on plantations in the Americas, and how the goods produced on those plantations were then sold in Europe. It also explains how some religious groups and activists like Thomas Clarkson began advocating against the slave trade in the late 1700s, establishing the Society for the Abolition of the Slave Trade in 1787 to lobby the British government. Their efforts eventually led to the British government banning the slave trade in 1807.
All digital wide range msar controlled duty cycle correctoracijjournal
A clock with 50% duty cycle is very significant in many applications such as DDR-SDRAMs and double
sampling analog-to-digital converters. This crisp presents a Modified Successive Approximation Register
(MSAR) controlled duty cycle corrector (DCC), to attain 50% duty cycle correction. Here MSAR adopts a
binary search method to compress lock time while maintaining tight synchronization between effort and
production clocks. The MSAR-DCC circuit has been implemented in a 0.18- μm CMOS process which
corrects the duty rate within 5 cycles which has a closed loop characteristics. The measured power
dissipation and area occupation are 5581nW and 0.033mm2 respectively.
Pso based optimized security scheme for image authentication and tamper proofingcsandit
The hash function offers an authentication and an integrity to digital images. In this paper an
innovative optimized security scheme based on Particle swarm optimization (PSO) for image
authentication and tamper proofing is proposed. This scheme provide solutions to the issues
such as robustness, security and tamper detection with precise localization. The features are
extracted in Daubechies4 wavelet transform domain with help of PSO to generate the image
hash. This scheme is moderately robust against attacks and to detect and locate the tampered
areas in an image. The experimental results are presented to exhibit the effectiveness of the
proposed scheme.
This document analyzes the effects of shadowing and fading on the performance of ad hoc routing protocols in mobile ad hoc networks (MANETs). It simulates the performance of three routing protocols - Location-Aided Routing (LAR), Routing Information Protocol (RIP), and LANMAR - under different shadowing and fading conditions using the QualNet simulator. The simulation evaluates the protocols based on application layer metrics like end-to-end delay, jitter, throughput, and packet delivery ratio, as well as physical layer metrics like power consumption and battery usage. The results show the impact of realistic channel models like shadowing and fading on routing protocol performance in MANETs.
The Effect of PMD (Polarization Mode Dispersion) the Fibers of New and Old In...inventionjournals
This is a study conducted in a laboratory at the university as a simulation to see the effect of new fiber PMD for different distances. This is done to compare the performance of the digital system with optical fiber WDM. In this simulation are not included remission, chromatic dispersion and nonlinear effects. In this way all of the signal distortions caused only by different combinations of PDM. Polarization effects are very important in communications systems with optical fiber. Optical fiber that is used mainly during the simulation is a standard single mode fiber (SSMF).
This document proposes and analyzes a model for planning hybrid wireless-optical broadband access networks (WOBANs). A WOBAN combines the reliability of fiber optic networks with the flexibility of wireless networks. The document presents a primal model for optimally placing base stations and optical network units in a WOBAN. It develops constraints for user assignment, capacity, interference and develops a Lagrangean relaxation approach and primal algorithm to obtain upper and lower bounds for the solution to the primal model. Simulation results are used to compare the primal model to a cellular heuristic placement approach.
This document discusses enhancing the capacity of the wireless portion of a hybrid wireless-optical broadband access network (WOBAN) through the strategic placement of additional radios at bottleneck nodes. Deploying multiple radios at every node improves performance but increases costs. The document proposes formulating the problem of optimally placing a limited number of additional radios as an integer linear program to maximize performance while minimizing costs. Prior work on routing, capacity assignment, and radio placement in wireless mesh networks is reviewed. The impact of deploying multiple radios only at overloaded bottleneck nodes is studied through numerical examples.
Joint Interference Coordination and Spatial Resource ReuseIJMTST Journal
Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. Deploying relay nodes is foreseen a cost-efficient solution to combat the severe propagation loss at cell edge. However, relay cell coverage is limited by the low transmit power, limited antenna capabilities and wireless backhaul link bottleneck which may lead to load imbalances and hence low resource utilization efficiency. Further challenges in relay deployments are attributed to increased interference levels in the network compared with macro cell-only deployments, causing degradation of the user throughput. In this context, relay cell coverage expansion and interference coordination techniques are expected to improve the performance of relay deployments. In this study, we analyze the impact of the additional interference due to the relay node transmissions. Jointly with our previous study on cell expansion, spatial resource reuse from the graph-theoretical perspective. Next, our focus shifts to developing a simple but efficient radio resource management algorithm which enables the spatial resource reuse, the pricing- based radio resource management (PRRM) strategy. The PRRM performs spatial reuse for interference-free users operating in the high signal-to-interference-and-noise ratio (SINR) region, while guaranteeing the signal quality of interference-susceptible users usually located near the coverage boundary. By applying the PRRM, we evaluate the potential benefits of the spatial resource reuse.
EFFICIENT REAL-TIME VIDEO TRANSMISSION IN WIRELESS MESH NETWORK IJORCS
This document summarizes a research paper on efficient real-time video transmission in wireless mesh networks. It begins with an introduction to wireless mesh networks and their benefits. It then discusses some key challenges for real-time video transmission, including unpredictable delays, packet loss, and delay jitter due to the error-prone nature of wireless links. The paper proposes a model to provide high-capacity data transfer with reduced delay for real-time video. It simulates this model using OPNET and achieves higher throughput results. Node models for the video server, receiver, access point, and FTP client/server are also described.
Energy Efficient Resource Allocation and Relay Selection Schemes for D2D Comm...ijtsrd
Device to Device D2D communication is a wireless peer to peer service, that allows direct communication to discharge hub input by binding wireless broadcasting amongst devices, as a vital technology module for next generation cellular communication system. Mobile devices limited battery power is a barricade for harnessing the performance of cellular communication systems. High data rate Device to Device communication is requisite to boost the crescent traffic requirement of apparent applications. In this paper suggest a centralized relay selection and power allocation process to state a multi objective optimization trouble to clearance the commutation in between total transmit power and system throughput. The proposed framework, suggest lowest perplexity modulation and demodulation procedure by route discovery for Generalized frequency division multiplexing systems. The proposed diplomacy deed the peculiar framework of the modulation matrix to depress the computational rate in the absence of meet with any performance loss distress. Centralized algorithm to discover the outcome in polynomial time. Proposed algorithms markedly minimize the total transmit power and enhance the system throughput. Surya S M | Prof. K. Kalai Selvi "Energy-Efficient Resource Allocation and Relay Selection Schemes for D2D Communications in 5G Wireless Networks" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-3 , April 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30413.pdf Paper Url :https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/30413/energyefficient-resource-allocation-and-relay-selection-schemes-for-d2d-communications-in-5g-wireless-networks/surya-s-m
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
Introductory Approach on Ad-hoc Networks and its Paradigms IJORCS
This document provides an introductory overview of ad-hoc networks, including:
1) A definition of ad-hoc networks as decentralized wireless networks that self-configure without preexisting infrastructure;
2) A discussion of mobile ad-hoc networks (MANETs) and wireless sensor networks as examples of ad-hoc networks;
3) An overview of challenges in providing quality of service in ad-hoc networks given their dynamic topology.
This document summarizes research on improving the capacity of cellular systems using fractional frequency reuse (FFR). It discusses how frequency reuse is used to increase the number of users that can be served but causes interference, particularly for cell edge users. Fractional frequency reuse is proposed to solve this problem by allocating different frequency sets to cell center and edge users to reduce interference. The document also reviews different types of interference (co-channel and adjacent channel) and how power control can help reduce interference in cellular systems.
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.
Wideband Sensing for Cognitive Radio Systems in Heterogeneous Next Generation...CSCJournals
Mobile Next Generation Network (MNGN) is characterized as heterogeneous network where variety of access technologies are meant to coexist. Decisions on choosing an air interface that meets a particular need at a particular time will be shifted from the network’s side to (a more intelligent) user’s side. On top of that network operators and regularities have come to the realization that assigned spectrum bands are not utilized as they should be. Cognitive radio stands out as a candidate technology to address many emerging issues in MNGN such as capacity, quality of service and spectral efficiency. As a transmission strategy, cognitive radio systems depend greatly on sensing the radio environment. In this paper, we present a novel approach for interference characterization in cognitive radio networks based on wideband chirp signal. The results presented show that improved sensing accuracy is maintained at tolerable system complexity.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document summarizes performance evaluation in wireless networks. It discusses how mobile ad hoc networks are self-configuring networks of wireless devices that can communicate directly or through intermediate nodes. It outlines some key characteristics of MANETs including dynamic topology, bandwidth constraints, and energy constraints. It also discusses different routing approaches for MANETs such as proactive (table-driven) and reactive (on-demand) protocols. Finally, it provides an overview of the operating principles of MANETs through an example network topology.
This document discusses dispersion compensation techniques for optical code division multiple access (OCDMA) systems using dispersion compensation fiber (DCF) and fiber gratings. It compares the performance of an 8-user OCDMA system using DCF versus fiber gratings. The results show that DCF more effectively compensates for dispersion, as evidenced by a lower bit error rate and higher Q factor, making it a better dispersion compensation method for OCDMA systems compared to fiber gratings.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Different Issues and Survey of Proposed Solutions in TCP over Wireless Enviro...Ranjeet Bidwe
This document discusses issues with using TCP in wireless networks and proposed solutions. The main issues are higher bit error rates, lower bandwidth, mobility, and longer round trip times in wireless networks compared to wired networks. TCP was designed for wired networks and assumes packet loss is always due to congestion, but in wireless networks loss can occur for other reasons like bit errors, handoffs, or disconnections. This wrong assumption causes TCP to reduce its window size unnecessarily, degrading performance. The document surveys proposed solutions like Snoop to cache packets at base stations to hide losses from the sender, and Explicit Congestion Notification to signal congestion before queue overflows.
This paper analyzes the performance of three routing protocols (AODV, DSDV, OLSR) for mobile WiMAX networks using the random direction mobility model in NS3 simulator. The protocols are evaluated based on routing overhead, packet delivery ratio, throughput, end-to-end delay, and packet loss. The results found that OLSR protocol outperformed AODV and DSDV, with lower routing overhead and higher packet delivery ratio, demonstrating improved efficiency for WiMAX networks.
The document discusses media access control (MAC) strategies for shared transmission media. It begins by explaining the need for MAC in cases where multiple users share a common channel. It then discusses different MAC approaches such as scheduling versus random access, centralized versus distributed control, and examples including TDMA, slotted ALOHA, and CSMA/CD. Key MAC influences like distance between stations, throughput requirements, traffic patterns are also covered. Specific MAC protocols discussed include those used in ISDN, Ethernet, GSM, and wireless networks.
QuScient is a profitable, debt-free company that provides outsourced higher education services from its 360-seat facility in Chennai, India and office in Phoenix, AZ. It offers a range of products and solutions for lead generation, enrollment, academic records, advising, and retention. Key services include a 170-seat call center, application processing, transcript evaluation, technical support, recruitment and monitoring of adjunct faculty, and the ProRetention student relationship management suite.
The document discusses the triangular slave trade that occurred between Europe, Africa, and the Americas in the 18th century. It describes how Great Britain financially benefited from transporting slaves from Africa to work on plantations in the Americas, and how the goods produced on those plantations were then sold in Europe. It also explains how some religious groups and activists like Thomas Clarkson began advocating against the slave trade in the late 1700s, establishing the Society for the Abolition of the Slave Trade in 1787 to lobby the British government. Their efforts eventually led to the British government banning the slave trade in 1807.
All digital wide range msar controlled duty cycle correctoracijjournal
A clock with 50% duty cycle is very significant in many applications such as DDR-SDRAMs and double
sampling analog-to-digital converters. This crisp presents a Modified Successive Approximation Register
(MSAR) controlled duty cycle corrector (DCC), to attain 50% duty cycle correction. Here MSAR adopts a
binary search method to compress lock time while maintaining tight synchronization between effort and
production clocks. The MSAR-DCC circuit has been implemented in a 0.18- μm CMOS process which
corrects the duty rate within 5 cycles which has a closed loop characteristics. The measured power
dissipation and area occupation are 5581nW and 0.033mm2 respectively.
Pso based optimized security scheme for image authentication and tamper proofingcsandit
The hash function offers an authentication and an integrity to digital images. In this paper an
innovative optimized security scheme based on Particle swarm optimization (PSO) for image
authentication and tamper proofing is proposed. This scheme provide solutions to the issues
such as robustness, security and tamper detection with precise localization. The features are
extracted in Daubechies4 wavelet transform domain with help of PSO to generate the image
hash. This scheme is moderately robust against attacks and to detect and locate the tampered
areas in an image. The experimental results are presented to exhibit the effectiveness of the
proposed scheme.
1) Wavelength shifters are fluorescent chemicals that can absorb ultraviolet Cherenkov photons and re-emit them at longer wavelengths detectable by photomultiplier tubes, improving light yield.
2) The document studies potential wavelength shifters for use in the Sudbury Neutrino Observatory heavy water Cherenkov detector to increase detection efficiency.
3) It tests several water-soluble wavelength shifter candidates, measuring their optical properties, stability, and compatibility with detector materials to find suitable options for deploying in the detector to boost the Cherenkov signal.
DESIGN AN AR APPLICATION IN FINDING PREFERRED DINING PLACE WITH SOCIAL NETWOR...acijjournal
Location Based Service (LBS) application help people in finding places or point of interest. However, spatial information in LBS is presented as a map in a small mobile device screen which makes the user difficult to understand and to find the location they need. It is possible that user might have disorientation in finding the place although they are presented with correct map. ARAFEPs (Augmented Reality Assistant to Finding Preferred Dining Place) is an Augmented Reality application to support its user to find the nearest and preferred dining place such as restaurant, fast food and food court. It is developed using Layar AR as platform. It presents the user with spatial information in a way that user could aware and understand the places surround them. Additional and relevant information that are presented in AR aids users to decide which dining place fits the needs of the user.
This document discusses audio indexing and classification. It notes that (1) most stored data is multimedia like audio which is difficult to handle manually due to its large volume, and (2) an automatic method is needed to organize and use multimedia data appropriately. It then explores using linear prediction residual and suprasegmental features of audio signals to classify audio clips, as these carry additional perceptual information not captured by existing spectral analysis methods. The residual and suprasegmental features are shown to provide discriminative information between different audio classes.
This document provides an overview of modeling wireless communication systems using MATLAB. It discusses:
1) Characterizing the wireless channel from the physics of propagation to multi-path fading channels and statistically modeling aspects like Doppler spectrum, delay spread, coherence time and bandwidth.
2) Simulating multi-path fading channels in MATLAB and using lumped parameter models to represent discrete-time equivalent channels.
3) Explaining path loss models, link budgets and shadowing and giving examples of free space propagation and two-ray path loss models.
SOURCE CODE ANALYSIS TO REMOVE SECURITY VULNERABILITIES IN JAVA SOCKET PROGR...IJNSA Journal
This paper presents the source code analysis of a file reader server socket program (connection-oriented
sockets) developed in Java, to illustrate the identification, impact analysis and solutions to remove five
important software security vulnerabilities, which if left unattended could severely impact the server
running the software and also the network hosting the server. The five vulnerabilities we study in this
paper are: (1) Resource Injection, (2) Path Manipulation, (3) System Information Leak, (4) Denial of
Service and (5) Unreleased Resource vulnerabilities. We analyze the reason why each of these
vulnerabilities occur in the file reader server socket program, discuss the impact of leaving them
unattended in the program, and propose solutions to remove each of these vulnerabilities from the
program. We also analyze any potential performance tradeoffs (such as increase in code size and loss of
features) that could arise while incorporating the proposed solutions on the server program. The
proposed solutions are very generic in nature, and can be suitably modified to correct any such
vulnerabilities in software developed in any other programming language. We use the Fortify Source
Code Analyzer to conduct the source code analysis of the file reader server program, implemented on a
Windows XP virtual machine with the standard J2SE v.7 development kit
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
This document summarizes a study on reducing four-wave mixing (FWM) effect in a hybrid optical CDMA/WDM system through simulation. FWM is a nonlinear effect in optical fibers that induces crosstalk between channels. The study presents a frequency allocation technique using unequal channel spacing to minimize FWM crosstalk. It simulates a fiber Bragg grating (FBG)-based frequency-hopping optical CDMA system combined with 10-channel WDM using the frequency allocation. The bit error rate performance is evaluated for 10 simultaneous users over 1km and 10km of fiber, showing improved performance with the unequal channel spacing approach. In conclusion, the document demonstrates a method of designing WDM channel spacing to reduce F
This document discusses symbolic test generation for compositional real-time systems. It motivates the research by explaining that real-time systems have both behavioral and time constraints, and that testing subsystems individually can reduce costs but integration testing poses challenges. The problem is defined as how to validate the behavior of compositional real-time systems using symbolic specifications. The research questions aim to define composition operators for symbolic models, determine challenges in inferring conformance based on composites, and generate integration tests from composed models. Preliminary results include defining sequential and parallel composition operators and applying them in a case study.
Frederick Douglass argued that by remaining silent, people allow injustice and wrongs to be imposed on them. His quote advises that speaking up is important to prevent the acceptance of unfair treatment. By finding what people will submit to without complaint, one can measure the level of injustice they will endure.
El documento resume las celebraciones de la fundación de Arequipa, incluyendo el paseo del estandarte de la ciudad, la misa y el Te Deum presididos por el Arzobispo. También describe varias actividades recientes de la iglesia como la inauguración de la biblioteca de Bustamante y Rivero, la entrega de biblias a nuevos integrantes del Camino Neocatecumenal, y un curso sobre la Eucaristía para 800 jóvenes en Yanahuara. El Arzobispo reflexiona sobre el significado del Reino de
El documento presenta una revisión del marco teórico de una investigación sobre la calidad de gestión docente. Explica los componentes clave de un marco teórico como los antecedentes de investigación, bases teóricas, definición de términos y variables. También describe el paradigma hermenéutico y diseño no experimental utilizado, incluyendo cuestionarios validados y confiables aplicados a una muestra de 33 sujetos para recopilar datos sobre factores de calidad docente.
Context-Aware Intrusion Detection and Tolerance in MANETsIDES Editor
Mobile ad-hoc network (MANET) is a
decentralized network where each node will forward the data
to other nodes. The major challenge in handling security in
MANETs is that the network is not constant and thereby it is
difficult to set a constant algorithm for detecting the intrusion.
In this work, a context-aware intrusion detection and
tolerance module for MANETs is proposed. A node in
MANET can be a filtering node or a monitor node. The
intrusion detection based on context awareness is done with
the help of filtering and monitoring nodes and intrusion
tolerance is done with the help of membership policy. The
filtering nodes have minimum level of static database and the
monitoring nodes have a database with learning capability.
For tolerance, the nodes which are not a member are denied
service while the nodes which are members are allowed the
service according to some specific rules.
A educação a distância teve início na Grécia e Roma através de cartas, e se desenvolveu ao longo dos séculos com o ensino por correspondência e o uso de novas tecnologias como rádio, TV e computadores. Instituições como a Universidade de Wisconsin e a Universidade de Chicago foram pioneiras em oferecer cursos por correspondência no século XIX. A partir da década de 1960 a educação a distância passou a integrar diferentes mídias como áudio, vídeo e computadores em seus cursos.
This document provides an overview of transaction security issues in e-commerce. It discusses how online transactions face threats from infrastructure, organizational, network and application vulnerabilities. Proper security management, including firewalls, network security controls and authentication are needed to protect sensitive information. Specifically, internet banking requires intrusion detection systems and legal frameworks to address security problems from insiders and across borders. Improving consumer education and trust are important for the long term success and growth of secure e-commerce transactions.
This document discusses a new approach for clustering in mobile ad hoc networks (MANETs) called the cluster head gateway (CHG) approach. The CHG approach aims to reduce overhead, increase energy efficiency, and improve reliability in MANETs. It removes the election of separate cluster heads and gateway nodes, instead having a single node act as both the cluster head and gateway for its cluster. This node is called the CHG node. The approach also introduces a prediction table to select a backup CHG node in case the primary CHG moves or fails. This helps maintain the cluster structure and routing information for increased reliability.
This module aims to explore concepts in cell biology, anatomy, developmental biology, and functional genomics related to stem cells and tissue engineering. Students will learn about ethical issues, limitations of current technology, and applications of cell culture. Through problem-based learning, students will work in teams to respond to real-world scenarios and challenges without a single correct answer. Assessment will consider class participation, presentations, conceptual understanding, and learning attitudes. The module does not include laboratory sessions.
The document discusses ad hoc and sensor networks. It provides sample questions and answers related to various topics in this area. Some key points covered include:
- Characteristics of wireless channels include path loss, fading, interference, Doppler shift, and transmission rate constraints.
- Shannon's theorem states the maximum possible data rate on a noisy channel as a function of bandwidth and signal-to-noise ratio.
- An ad hoc network is a decentralized type of wireless network without any fixed infrastructure. It is suitable for situations where a wired network cannot be setup.
- Challenging issues in ad hoc network maintenance include medium access, routing, multicasting, transport layer protocols, pricing schemes, and quality of service
Dense wavelength division multiplexing....Arif Ahmed
The document discusses performance analysis of dense wavelength division multiplexing (DWDM) optical transmission systems. It begins with an introduction to DWDM, which allows transmission of up to 132 wavelengths over a single fiber. Section 2 provides an overview of optical fiber transmission and prior multiplexing techniques such as time division, frequency division, subcarrier, and coarse and dense wavelength division multiplexing. Section 3 indicates that the performance of DWDM will be analyzed using its application in NEMO, ANTARES, and KM3NeT underwater neutrino telescope experiments.
A QoS Based MAC Protocol For Wireless Ad-hoc NetworkIJNSA Journal
Multimedia communication over wireless Ad-hoc networks has become the driving technology for many of the important applications, experiencing dramatic market growth and promising revolutionary experiences in personal communication, gaming, entertainment, military, security, environment monitoring, and more. The advances in wireless communications and growth of real-time applications have necessitated the development of wireless networks that can support high Quality of Service (QoS) and power control. A node in an ad hoc network is normally battery operated which poses a huge constraint on the power consumption of such a node. Hence, designing a power efficient MAC protocol for ad hoc wireless networks is a major challenge. In this paper, we propose a CDMA based power controlled medium access protocol for mobile and ad hoc network (MNA). The protocol conserves power and provides QoS guarantees for multimedia traffics. In that network one of the fundamental challenger in MANETs is how to increase the overall network throughputs well as reading the delay while maintaining how energy consumption for packet processing in communication. simulation results shows that the performance of the protocol with increase in traffic while QoS is better in terms of Energy consumption, throughput, & communication delay than existing protocol.
Performance of symmetric and asymmetric links in wireless networks IJECEIAES
Wireless networks are designed to provide the enabling infrastructure for emerging technological advancements. The main characteristics of wireless networks are: Mobility, power constraints, high packet loss, and lower bandwidth. Nodes’ mobility is a crucial consideration for wireless networks, as nodes are moving all the time, and this may result in loss of connectivity in the network. The goal of this work is to explore the effect of replacing the generally held assumption of symmetric radii for wireless networks with asymmetric radii. This replacement may have a direct impact on the connectivity, throughput, and collision avoidance mechanism of mobile networks. The proposed replacement may also impact other mobile protocol’s functionality. In this work, we are mainly concerned with building and maintaining fully connected wireless network with the asymmetric assumption. For this extent, we propose to study the effect of the asymmetric links assumption on the network performance using extensive simulation experiments. Extensive simulation experiments were performed to measure the impact of these parameters. Finally, a resource allocation scheme for wireless networks is proposed for the dual rate scenario. The performance of the proposed framework is evaluated using simulation.
In recent past the influence of Radar has played a significant part in various fields. Radar sensing is one of
the prime application by which velocity and distance of a moving target can be found out. A joint RadCom
system to serve both radar sensing and wireless communication is proposed which ensures better
performance in terms of spectral efficiency, extended detection range and cost effectiveness. Such systems
demand for a common waveform which is designed in this work that perfectly matches to the system
requirements. OFDM multi carrier technique is chosen to generate a common waveform. Applicability of
multiple antenna technique for direction of arrival estimation is also considered. MIMO-OFDM technique
has gained much interest in the field of communication which improves the signal to noise ratio and lowers
the bit error rate. On the other hand the usage of MIMO reflects in the form of interference between
signals. In order to overcome this effect beamforming technique is used. In addition to theoretical
explanations we have also simulated and discussed the results for the proposed RadCom system using
MATLAB simulation tool.
This document proposes techniques to reduce interference in WCDMA networks through cell resizing. It begins with background on WCDMA and sources of interference. It then proposes classifying cells as normal, saturated or cooperative based on SNR measurements. Saturated cells trigger a cell resizing process where users are transferred to neighboring cooperative cells to balance load and cancel interference. Simulation results showed this approach reduces blocking probability and achieves optimal transmission rates with reduced delay.
This document provides an overview of reconfigurable intelligent surfaces (RIS) for wireless communications. It discusses two main implementations of RIS - using reflectarrays or metasurfaces. Reflectarray-based RIS use electronically controlled antenna elements to backscatter and phase-shift incident signals, while metasurface-based RIS can precisely control the amplitude and phase of scattered waves using subwavelength resonant structures. The document also examines how RIS can impact channel modeling and optimize wireless system performance by controlling propagation environments. RIS have the potential to improve capacity and overcome challenges in higher frequency bands by enhancing channel conditions.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
The document discusses investigating the optimum number of neighbors for mobile ad hoc networks (MANETs). It begins with background on MANETs and their characteristics. It then reviews related work that has looked at optimizing parameters like transmission range and node density. The paper aims to find the optimum number of neighbors under static, low mobility, and high mobility conditions using simulations. It analyzes performance metrics like end-to-end delay, throughput, energy consumption, and routing overhead to determine if there is an optimum number and if it differs based on mobility. The document outlines the investigation and summarizes key related work to provide context.
Optimum Neighbors for Resource-Constrained Mobile Ad Hoc Networksijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
Wireless networking has been an active research focus since the early days of the packet radio
network introduced by the Defense Advanced Research Project Agency (DARPA) [1]. Recent
developments in wireless devices have made laptop computers, personal digital assistants (PDA),
pagers, and cellular telephones portable. Now, users can carry these devices to any place at any
time. Hence, there is a need for a network that can be deployed at any place at any time without
any infrastructure support. In some cases, an infrastructure-based network is hard to build.
Networks used by the soldiers on the battlefield are worthwhile to mention here. In some cases,
infrastructures may not exist due to natural calamities such as cyclones, tsunami, and tornados.
Hence, there is always a need for setting up a temporary network among a group of users without
any pre-existing infrastructure and centralized administration. Mobile Ad hoc Networks
(MANETs) are considered suitable solutions for these kinds of temporary networks. MANETs
consist of a group of mobile nodes, which have limited battery and limited processing power.
MANETs are self-organizing and self-configuring networks and they can be deployed without any
infrastructure support. Numerous groundbreaking applications have been proposed based on
MANETs. These applications include disaster management, search and recovery, remote
International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.12, No.2, April 2021
2
healthcare, tele-geoprocessing, education, traffic management, process control, and security [2].
These applications impose diversified design and performance constraints on the MANETs.
OPTIMUM NEIGHBORS FOR RESOURCECONSTRAINED MOBILE AD HOC NETWORKSijasuc
This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks
(MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes
have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile
nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors
is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To
investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11
as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We
simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists
an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the
performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and
packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there
is no global optimum number of neighbors for the mobility case.
Impact of Next Generation Cognitive Radio Network on the Wireless Green Eco s...ijeei-iaes
Land mobile communication is burdened with typical propagation constraints due to the channel characteristics in radio systems.Also,the propagation characteristics vary form place to place and also as the mobile unit moves,from time to time.Hence,the tramsmission path between transmitter and receiver varies from simple direct LOS to the one which is severely obstructed by buildings, foliage and terrain. Multipath propagation and shadow fading effects affect the signal strength of an arbitrary Transmitter-Receiver due to the rapid fluctuations in the phase and amplitude of signal which also determines the average power over an area of tens or hundreds of meters. Shadowing introduces additional fluctuations, so the received local mean power varies around the area –mean. The present paper deals with the performance analysis of impact of next generation wireless cognitive radio network on wireless green eco system through signal and interference level based k coverage probability under the shadow fading effects.
This document discusses collision avoidance mechanisms in wireless ad hoc networks using distributed medium access control (MAC) protocols. It analyzes two main approaches for collision avoidance - out-of-band signaling using a busy tone, and an in-band handshaking approach using request-to-send and clear-to-send messages. The hidden node problem is a major cause of collisions at intermediate nodes in ad hoc networks, so the goal is to reduce collisions and improve transmission reliability. Algorithms for collision avoidance at intermediate nodes are presented for both the out-of-band and in-band approaches.
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.
Intersatellite laser crosslinks provide significantly higher data throughput than traditional RF communication systems. They take advantage of lasers' small wavelengths and highly directed beams to transmit data over long distances with minimal losses. A laser crosslink system consists of a transmitter, receiver, acquisition subsystem to initially align the links, and a tracking subsystem to maintain the alignment during data transmission. Optical communications offer wide bandwidths and high data transmission rates well beyond what is possible with RF technologies. Various laser crosslink systems are discussed to understand their subsystems and implementations.
Performance of modeling wireless networks in realistic environmentCSCJournals
A wireless network is realized by mobile devices which communicate over radio channels. Since, experiments of real life problem with real devices are very difficult, simulation is used very often. Among many other important properties that have to be defined for simulative experiments, the mobility model and the radio propagation model have to be selected carefully. Both have strong impact on the performance of mobile wireless networks, e.g., the performance of routing protocols varies with these models. There are many mobility and radio propagation models proposed in literature. Each of them was developed with different objectives and is not suited for every physical scenario. The radio propagation models used in common wireless network simulators, in general researcher consider simple radio propagation models and neglect obstacles in the propagation environment. In this paper, we study the performance of wireless networks simulation by consider different Radio propagation models with considering obstacles in the propagation environment. In this paper we analyzed the performance of wireless networks by OPNET Modeler .In this paper we quantify the parameters such as throughput, packet received attenuation.
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.
SHADOWING EFFECTS ON ROUTING PROTOCOL OF MULTIHOP AD HOC NETWORKSijasuc
Two-ray ground reflection model has been widely used as the propagation model to investigate the
performance of an ad hoc network. But two-ray model is too simple to represent a real world network. A
more realistic model namely shadowing propagation model has been used in this investigation. Under
shadowing propagation model, a mobile node may receive a packet at a signal level that is below a
required threshold level. This low signal level affects the routing protocol as well as the medium access
control protocol of a network. An analytical model has been presented in this paper to investigate the
shadowing effects on the network performance. The analytical model has been verified via simulation
results. Simulation results show that the performance of a network becomes very poor if shadowing
propagation model is used in compare to the simple two-ray model. Two solutions have also been proposed
in this paper to overcome the effects of shadowing. One solution is a physical layer solution and the other
one is a Medium Access Control (MAC) layer solution. Simulation results show that these two solutions
reduce the shadowing effect and improve network performance.
SHADOWING EFFECTS ON ROUTING PROTOCOL OF MULTIHOP AD HOC NETWORKSijasuc
Two-ray ground reflection model has been widely used as the propagation model to investigate the
performance of an ad hoc network. But two-ray model is too simple to represent a real world network. A
more realistic model namely shadowing propagation model has been used in this investigation. Under
shadowing propagation model, a mobile node may receive a packet at a signal level that is below a
required threshold level. This low signal level affects the routing protocol as well as the medium access
control protocol of a network. An analytical model has been presented in this paper to investigate the
shadowing effects on the network performance. The analytical model has been verified via simulation
results. Simulation results show that the performance of a network becomes very poor if shadowing
propagation model is used in compare to the simple two-ray model. Two solutions have also been proposed
in this paper to overcome the effects of shadowing. One solution is a physical layer solution and the other
one is a Medium Access Control (MAC) layer solution. Simulation results show that these two solutions
reduce the shadowing effect and improve network performance.
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Alt. GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using ...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
IJCER (www.ijceronline.com) International Journal of computational Engineering research
1. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
Statistical Multipath Signal Detection in CDMA for Ad hoc Network.
H. Umadevi1, K.S. Gurumurthy2, Chandrakanth Gowda3
1
Department of Electronics & Communication, Dr Ambedkar Institute of Technology
2
Department of Electronics & Communication, UVCE, Bangalore
3
Department of Electronics & Communication, KSIT, Bangalore
Abstract:
Mobile ad hoc networks (MANETs) represent complex Characters and Fundamental Challenges of Wireless
distributed systems that comprise wireless mobile nodes Ad-hoc Networks
that can freely and dynamically self-organize into arbitrary Since Wireless Ad-hoc Networks are inherently different
and temporary, ‘‘ad-hoc’’ network topologies, allowing from the well-known wired networks, it is an absolutely
people and devices to seamlessly internetwork in areas new architecture. Thus some challenges raise from the two
with no pre-existing communication infrastructure, e.g., key aspects: self-organization and wireless transport of
disaster recovery environments. Ad hoc networking information [2], [3]. First of all, since the nodes in a
concept is not a new one, having been around in various Wireless Ad-hoc Network are free to move arbitrarily at
forms for over 20years.Ad Hoc networks are multi-hop any time. So the networks topology of MANET may
wireless networks where nodes may be mobile. These change randomly and rapidly at unpredictable times. This
types of networks are used in situations where temporary makes routing difficult because the topology is constantly
network connectivity is needed. Ad hoc networks are changing and nodes cannot be assumed to have persistent
formed on a dynamic basis, i.e. a number of users may data storage. In the worst case, we do not even know
wish to exchange information and services between each whether the node will still remain next minute, because the
other on an ad hoc basis, in order to do this they will need node will leave the network at any minute. Bandwidth
to form an Ad Hoc network. Multipath signal detection is constrained is also a big challenge. Wireless links have
done using BPSK for CDMA Extended for OFDM and significantly lower capacity than their hardwired
calculated the BER and that signal is analyzed in Ad hoc counterparts. Also, due to multiple access, fading, noise,
Network. and interference conditions etc. the wireless links have
low throughput. Energy constrained operation. Some or all
Keywords: Ad hoc, BER, BPSK, CDMA, MANETs, of the nodes in a MANET may rely on batteries. In this
OFDM, SNR. scenario, the most important system design criteria for
optimization may be energy conservation. Limited
I Introduction physical security: Mobile networks are generally more
It is important to evaluate the performance of wireless prone to physical security threats than are fixed cable
devices by considering the transmission characteristics, networks. MANETs are internetworks formed by mobile
wireless channel parameters and device structure. The wireless routers, with each router having one or more
performance of data transmission over wireless channels is associated host devices (e.g., computers and sensors). A
well captured by observing their BER, which is a function MANET’s router implements routing protocols that—
of SNR [1] at the receiver. In wireless channels, several unlike conventional routing techniques—tolerate rapid
models have been proposed and investigated to calculate changes in connectivity among nodes. The paper is
SNR. All the models are a function of the distance organized as follows. Section II explains Rayleigh fading,
between the sender and the receiver, the path loss CDMA, and OFDM. Section III deals with the
exponent and the channel gain. Several probability implementation. Section IV deals with results and
distributed functions are available to model a time-variant discussions. The paper is concluded in Section
parameter i.e. channel gain. The term ad hoc often means
improvised or for the needs o the moment for a specific II Rayleigh Fading, Cdma, and Ofdm
purpose. In Computer networking, we The Rayleigh fading is primarily caused by multipath
Think of ad hoc network as a wireless network. Without reception [4]. Rayleigh fading is a statistical model for the
any infrastructure, e.g. wireless base effect of a propagation environment on a radio signal. It is
Stations. More thoroughly described, an ad hoc network a reasonable model for troposphere and ionospheres signal
consists of a number of nodes with wireless propagation as well as the effect of heavily built-up urban
communication capabilities that potentially move around environments on radio signals. Rayleigh fading [5] is most
and cause the network topology to change frequently. applicable when there is no line of sight between the
transmitter and receiver.
Rayleigh fading is a statistical model for the effect of
a propagation environment on a radio signal, such as that
used by wireless devices. Rayleigh fading models assume
that the magnitude of a signal that has passed through such
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2. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
a transmission medium (also called a communications 2. Near Far Problem:
channel) will vary randomly, or fade, according to The problem is best described by taking and considering a
a Rayleigh distribution the radial component of the sum of receiver and two transmitters (one close to the receiver;
two uncorrelated Gaussian random variables. Rayleigh the other far away). If both transmitters transmit
fading model: The Rayleigh fading is primarily caused by simultaneously and at equal powers, then due to the
multipath reception. Rayleigh fading is a statistical model for inverse square, the receiver will receive more power from
the effect of a propagation environment on a radio signal. the nearer transmitter. This makes the farther transmitter
It is a reasonable model for troposphere and ionosphere voice more difficult to understand. Since one
signal propagation as well as the effect of heavily built-up transmission's signal than the farther transmitter, then the
urban environments on radio signals. Rayleigh fading is SNR for the farther transmitter may be below detect
most applicable when there is no line of sight between the ability and the farther transmitter may just as well not
transmitter and receiver. transmit. This effectively jams the communication
channel.
Rayleigh fading is a reasonable model when there are
many objects in the environment that scatter the radio OFDM
signal before it arrives at the receiver. The central limit Recently, a worldwide convergence has occurred for the
theorem holds that, if there is sufficiently much scatter, the use of Orthogonal Frequency Division multiplexing
channel impulse response will be well-modeled as (OFDM) as an emerging technology for high data rates. In
a Gaussian process irrespective of the distribution of the particular, many wireless standards (Wi-max,
individual components. If there is no dominant component IEEE802.11a, LTE, and DVB) have adopted the OFDM
to the scatter, then such a process will have zero mean and technology as a mean to increase dramatically future
phase evenly distributed between 0 and 2π radians. wireless communications. OFDM is a particular form of
The envelope of the channel response will therefore Multi-carrier transmission and is suited for frequency
be Rayleigh distributed. selective channels and high data rates. This technique
In CDMA there is no restriction on time and frequency. In transforms a frequency-selective wide-band channel into a
this scheme all the users can transmit at all times and at all group of non-selective narrowband channels, which makes
frequencies, as shown in Fig 1. Because users are isolated it robust against large delay spreads by preserving
by code, they can share the same carrier frequency, orthogonality in the frequency domain. Moreover, the
eliminating the frequency reuse problem encountered in ingenious introduction of cyclic redundancy at the
other transmitter reduces the complexity.
Technologies.
Multicarrier modulation splits the broadband channel into
a large number of (narrowband) sub channels. The total bit
stream is divided over these sub channels. These bits are
modulated per sub channel onto a subcarrier with standard
narrowband modulation techniques like PSK or QAM.
The sum of all the modulated subcarriers forms the
composite multicarrier signal that is sent over the channel.
When the subcarriers are orthogonal, the sub channels
may overlap without interfering each other, resulting in a
Fig1. Code Division Multiple Access high spectral efficiency (compared to e.g. frequency
Problems in Cdma Detection division multiplexing, where all the sub channels are
There are two problems encountered in CDMA Detection separated by guard bands to prevent interference). The
generation of these subcarriers is done in the digital
1. Multipath Fading: domain, so that only one global local oscillator is needed
In a mobile environment, a mobile station will receive one instead of one for each subcarrier. Normally the Fourier
direct signal from the base station and multiple signals Transform is used.
which are reflected from obstructions like buildings and
towers as shown in Fig 4. Each signal would have traveled A. Theoretical BER
a different length and would be displaced in time. Due to The BER, or quality of the digital link, is calculated from
this, when they are combined at the mobile handset, it will the number of bits received in error divided by the number
cause interference resulting in poor signal quality. This is of bits transmitted.
known as fading. This problem is handled in a very good
way in CDMA. Here, the phase of the multiple signals is BER= (Bits in Error) / (Total bits received).
modified such that only positive interference (addition)
takes place and the overall signal strength. A receiver that In digital transmission, the number of bit errors is the
implements the above principle is known as RAKE number of received bits of a data stream over a
receiver. communication channel that has been altered due to noise,
interference, distortion or bit synchronization errors. The
BER is the number of bit errors divided by the total
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3. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
number of transferred bits during a particular time spreading code, number of sub carriers 4, number of users
interval. BER is a unit less 15 and other parameters same as [6,8].
Performance measure, often expressed as a percentage [7]. B. Simulation Results
The theoretical BER for BPSK modulation scheme over
Rayleigh fading channel (with AWGN noise) is given by
The theoretical BER for BPSK modulation scheme over
an AWGN channel is given here for comparison
Figure 3.Eb/N0Vs BER
The Simulated and theoretical performance curves (Eb/N0
Eb / N0 BER in AWGN BER in Rayleigh Vs BER) for BPSK modulation over Rayleigh Fading
channel and the AWGN is shown in table and in figure2.
-5 : 0 0.1064 0.1033
III Implementation
0: 5 0. 0952 0.0944 Figure4. shows the generated signal from modulator is
transmitted in multipath via Rayleigh fading[9,10] channel
5: 10 0. 0578 0.0608 and at the receiver side having highest received power
signal is compared with threshold value and reordered in
10: 15 0. 0235 0.0275 descending order using statistical algorithm. The signal
having highest receiving power is selected for BER
15: 20 0. 0078 0.01
calculation. The implementation here is considered for
five channels. In this paper, one of the important topic in
20 : 25 0. 0025 0.0029
wireless communications that is the concept of fading[11-
Table 1. BER in AWGN and Rayleigh fading channel 13] is demonstrated by the approach available in
MATLAB. Simulink is a graphical extension to MATLAB
The following model is used for the simulation of BPSK for the modeling and simulation of systems. In Simulink,
over Rayleigh Fading channel and its comparison with systems are drawn on screen as block diagrams. Many
AWGN channel elements of block diagrams are available (such as transfer
functions, summing junctions, etc.), as well as virtual
input devices and output devices. Simulink is integrated
with MATLAB and data can be easily transferred between
the programs.
Figure2: BPSK Modulation over Rayleigh and AWGN
channel
Figure2 refers to modulation and BPSK detection over
Rayleigh and AWGN channel. Using BPSK modulation, Figure 4. Five channel with BPSK Modulation
randomly varying Rayleigh fading channel, Walsh
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4. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
IV Results and Discussions
The reverse and forward Link interoperations comprise of
convolution encoding and repetition, block interleaving,
long PN sequence, data scrambling, Walsh coding and
Quadrature modulation shown in figure 5 and 6and
figure7shows BER for five channels. The signal which is
having highest receiving power and better BER that signal
is considered (output signal from figure 4) and used to
transmit the signal over ad hoc Network and shortest path
algorithm is used to transmit the signal from source to
destination. Figure 8.Adhoc network
Figure 9.Adhoc network routing
Figure 5. Reverse channel.
Start
Nodes send signal to find the number of
other nodes within range
Synchronizing between nodes
Sender node send message to receiving node
Figure 6 Forward channel. Receiving
node Send Is receiving
Wait for
back Ready node ready
sometime
Signal
Communication begins
Termination Process
Figure 7. BER for five channel Stop
Figure 10.Adhoc network working
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5. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
V Conclusion
In this paper, the simulation of statistical multipath
signal passing through five different channels is
presented. The signal having the highest SNR is
considered at the receiver and the BER for that
particular signal is calculated, and obtained signal is
again used in wireless communication application ie in
Ad hoc network to transmit the information from source
to destination which uses the shortest path algorithm.
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[2] M. Satyanarayanan. Fundamental challenges in
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PHY Simulation Models”, MSWim‟ 08, October
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