Placements of Road Side Units (RSUs) are an important issue of vehicular networks in urban areas.... more Placements of Road Side Units (RSUs) are an important issue of vehicular networks in urban areas. The merged cost of procurement, installation, and maintenance of intelligent RSUs is high, and therefore, cost-effective deployment strategies are necessary. In this article, we propose a scheme that optimally deploys intelligent roadside units using a travel matrix scheme based on the classical delta strategy where urban vehicles are involved in RSUs communication in the course of their travel times. Four (4) vehicular communication modes are studied, namely, (a) travel matrix based on delta RSUs deployment communication, (b) road intersection-based RSUs deployment communication, (c) road segmentation, and (d) free vehicle-to-vehicle communication. A baseline algorithm is suggested to determine the optimal locations of RSUs in terms of their geographical positions. A travel matrix technique is proposed to trace vehicles’ routeways and travel times in some points of interest (POI). Our ...
5G multimedia mobile wireless network is designed to support on-demand encoding of rich mobile mu... more 5G multimedia mobile wireless network is designed to support on-demand encoding of rich mobile multimedia content for heterogeneous users. Due to the heterogeneity of the users, adaptive multimedia services are essential to provide a satisfactory Quality of Experience (QoE). In this paper, we propose a utility-based dynamic adaptive multimedia streaming scheme, named UDAS, for heterogeneous users that helps in extending the battery life of the low-battery users and also uses the bandwidth of the wireless channel efficiently. At each scheduling interval, the adaptation algorithm considers four utility functions of the user devices, namely, quality utility, power consumption utility, packet error ratio utility, and remaining battery utility to adapt the data rate dynamically. We formulate an optimization problem to maximize a joint utility function of these four utilities. The solution of the problem provides the best adaptive multimedia content that is selected for transmission to the end-users in every scheduling interval. The mobile edge computing (MEC) server situated at the base station performs an on-demand HEVC (high efficiency video coding) encoding of videos and select the best suitable videos for different users. Simulation results verify the improved performance of UDAS in terms of saved battery energy and the number of unserved low-battery users in comparison with state-of-the-art non-adaptive multimedia streaming schemes and a popular scheme ESDOAS from the literature.
2021 International Conference on COMmunication Systems & NETworkS (COMSNETS), 2021
Intricate data processing, reliable and quick message exchanges are the primary requirements to a... more Intricate data processing, reliable and quick message exchanges are the primary requirements to actualize the next-generation vehicular network applications in smart cities. The cellular macro base stations and IEEE 802.11p based WAVE technology can offer data connectivity to low mobility users but fails to support the high data rate and low latency requirement for next-generation vehicular network applications. The mmWave beam antennas, along with the edge computing technique of the 5G ecosystem, is capable of supporting such a service demands. Therefore RSUs equipped with mmWave beam antennas can be a pragmatic solution to this problem. However, the cost-efficient deployment of mmWave enabled 5 G RSUs on a smart city under a restricted budget presents a significant challenge. We address this issue by formulating it as a Budgeted Maximum Coverage optimization to place such 5G RSUs in an urban vehicular scenario efficiently. The optimization maximizes the long term profits under the constraint of a limited budget. The problem under consideration is an NP-hard problem. Therefore, we employ two approximation algorithms. The greedy algorithm is fast and guarantees $\frac{1}{2}\left(1-\frac{1}{e}\right)$ approximation. The modified-greedy algorithm is slower but guarantees $\left(1-\frac{1}{e}\right)$ approximation. We validate the performance of our proposed scheme in an urban city with real data.
2018 3rd International Conference on Microwave and Photonics (ICMAP), 2018
The paper presents design methodologies for elastic optical networks (EONs) with due consideratio... more The paper presents design methodologies for elastic optical networks (EONs) with due considerations to the survivability against link failures and guardband-constrained spectral allocations, using ILP and heuristic algorithms. The obtained results show that, there should be a tradeoff between the number of guardband slots and the spectrum utilization in EONs. Further, a comparative study has been carried out for blocking probabilities of general (unprotected) and survivable EONs with two different protection mechanisms, with due consideration to guardband slots.
Delay Tolerant Networks (DTNs) ranging from Inter-Planetary Networks (IPN) to Vehicular Ad Hoc Ne... more Delay Tolerant Networks (DTNs) ranging from Inter-Planetary Networks (IPN) to Vehicular Ad Hoc Networks (VANETs) are receiving continuous attention in recent years. The existing protocols for DTNs have been primarily designed and analyzed under the assumption that data traffic is either Constant Bit Rate (CBR) or Poisson. It has been observed that such models are incapable of capturing the inter-arrival behavior of the present day traffic which may be bursty in nature. The traffic characteristics in todays communication networks are statistically self-similar in nature, i.e., burstiness and correlation exists over many time scales, also referred to as Long Range Dependency (LRD). In this paper we analyze the traffic characteristics in the nodes of a delay tolerant network. Self-similar traffic is generated by implementing a traffic model in the source module of DTN. It is based on the model of aggregated ON/OFF sources. A mathematical analysis is provided to elucidate the cause of self similar nature of traffic in DTN. Through simulations and statistical analysis of the traffic data, we study the degree of selfsimilarity of traffic in the nodes of a vehicular delay tolerant network.
In this work, we have aimed at developing a new source location privacy preserving protocols to a... more In this work, we have aimed at developing a new source location privacy preserving protocols to achieve uniform privacy privacy irrespective of the location of the source in the network with enhanced privacy and network lifetime. This is done without the use of fake packets and fake source. The proposed technique falls under the category of Phantom-based Random Walk Technicues.
In this paper, we investigate an application of the Chinese Remainder Theorem (CRT) for a novel p... more In this paper, we investigate an application of the Chinese Remainder Theorem (CRT) for a novel privacy preserving routing technique in wireless sensor networks (WSNs). The distinctive nature of the proposed technique is gathering the data, aggregating and then slicing the aggregate using t-out-of-n secret sharing scheme (based on CRT) and then route the packets to the sink via multiple paths. The sink will recover the final aggregate with just t shares using CRT. The multi-objective of the proposed technique is to provide data privacy, identity privacy, source location privacy, and route privacy. The solution also mitigates the problem of packet losses associated with the unreliable wireless communication medium by improving the reliability. We also propose an enhanced privacy preserving routing technique that achieves network wide routing paths, and overcomes the drawback of existing phantom single-path routing (PSPR) and forward random walk-based routing (FRW) schemes. Finally, we present the details of the proposed technique with a numerical example and give its possible application for secret and dynamic routing in WSNs. We also show the simulation results to validate the proposed method and comparison with PSPR and FRW techniques demonstrates that our scheme outperforms the other two solutions.
2020 National Conference on Communications (NCC), 2020
The next generation vehicular applications in smart cities, including aided self-driving, require... more The next generation vehicular applications in smart cities, including aided self-driving, require intricate data processing and quick message exchanges. A pragmatic approach to address these requirements is to adopt the edge-computing paradigm from 5G architecture, where storage, computing, and networking resources are brought to the edge of the network, i.e., closer to the end-users. Edge nodes (EN) are geographically overlaid across a region, and therefore, the effectiveness of the vehicular applications is directly associated with the proper placement of such nodes. However, the deployment of edge nodes on the roadsides presents a challenge of cost-effectiveness. In this paper, we address the efficient deployment of a limited number of edge nodes in an urban scenario under a restricted budget. To this end, we jointly consider the structural properties of the road network using complex-network based centrality metrics and the vehicular traffic distribution to rank the candidate sites for edge node placement. Thereafter, we formulate the problem of edge node deployment as a 0–1 knapsack problem, which is a classical NP problem and provide a dynamic programming based solution to it. We evaluate the proposed method in an urban scenario with real traffic and present conclusive proof that our proposed scheme yields a practical solution to the defined problem.
Proceedings of the 21st International Conference on Distributed Computing and Networking, 2020
In the current context of the massive data traffic surge, the densification of the network seems ... more In the current context of the massive data traffic surge, the densification of the network seems to be an efficient alternative solution, which demands the installation of small cells (SCs) in the 5G networks leading to its complexity. This calls for an efficient way to manage such complex systems through centralized control and content delivery strategy to help the end-users access high data rate multimedia services quicker wherein the storage and the bandwidth resources are used more effectively. In this paper, we have proposed a cache aided content delivery strategy for the 5G heterogeneous network, where the base stations of all the SCs and the macro cell are connected to the local cache-enabled content server. Moreover, a centralized controller, having a global view of the underlying network, stands responsible for delivering the multimedia content from the local server to the requisite base stations. The strategy mentioned above is found to be a promising solution resulting in the perception of seamless connectivity, thereby improving the QoE (Quality of Experience) of multimedia services. The proposed Network Selection and Resource Allocation (NSRA) strategy are observed to provide a tradeoff between the system throughput and churn rate. Moreover, the minimum rate requirement for all served users in the system is ensured.
A novel computing paradigm, called the Internet of things emerged a few years ago. IoT is materia... more A novel computing paradigm, called the Internet of things emerged a few years ago. IoT is materialized by connecting both real and digital worlds together. The deployment of IoT in vehicular networks has introduced a new vehicular communication technology-themed vehicular internet of things (V-IoT). With the introduction of miniaturized sensors and actuators, V-IoT has demonstrated the ability to improve the level of urban transport systems through the development and deployment of low-cost but powerful technologies which seamlessly upgrade the level of smart transportation in urban environments. In this research article, we have presented the features of V-IoT that encompass both the benefits and potential challenges of the technology. Low-cost IoT prototypes have been built and tested for numerous functions in vehicular environments. The monitored parameters include air, road conditions such as traffics flow sizes, air quality, weather parameters, and signal status in terms of Rec...
Railway Bridge Health Monitoring is of prime importance as damages in bridges can lead to heavy c... more Railway Bridge Health Monitoring is of prime importance as damages in bridges can lead to heavy casualties. Hence, monitoring is necessary to provide safety services to the millions of people around the world. Recently, wireless sensor network (WSN) has come up as a promising technology for health monitoring. However, memory and energy constraints of WSN, and extracting intelligible information from signals obtained from complex bridge structures are the technical challenges in this domain. In this paper, we give a brief overview of a novel railway bridge health monitoring system using smart WSN.
In this Chapter, a software-defined network (SDN)-based framework for future smart cities has bee... more In this Chapter, a software-defined network (SDN)-based framework for future smart cities has been proposed and discussed. It also comprises a distributed addressing scheme to facilitate the allocation of addresses to devices in the smart city dynamically. The framework is dynamic and modules can be added and omitted by a centralized controlling unit without disturbing the other components of the framework and other modules may be updated accordingly. In the proposed addressing scheme, a new Internet of Things (IoT) device will receive an IP address from one of their existing neighboring peer devices. This allows devices in the city to act as a proxy and generate a set of unique IP addresses from their own IP addresses, which can then be assigned to new (joining) devices; hence, reducing addressing overhead and latency, as well as avoiding the need to send broadcast messages during the address allocation process. Thus, it achieves considerable bandwidth and energy savings for the Io...
IEEE Journal on Selected Areas in Communications, 2004
AbstractIn this paper, we present a polynomial time algorithm that gives an optimal solution to ... more AbstractIn this paper, we present a polynomial time algorithm that gives an optimal solution to the routing and wavelength assign-ment (RWA) problem in a tree topology. One of the major design issues in wavelength-division multiplexed networks is the assign-ment of the ...
2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC)
With device-to-device (D2D) based relay-assisted communications, deep faded cellular users (CUs) ... more With device-to-device (D2D) based relay-assisted communications, deep faded cellular users (CUs) get a better connectivity. The deep faded CU's achievable throughput of the link from base station (BS) to the CU is less than the rate demand from the CU (unsatisfied CUs). In this paper, we study the resource allocation problem for both CUs and D2D pairs to increase the achievable throughput. This is accomplished by reducing the difference between rate demand and rate achieved for the active CUs. The resource allocation optimization problem is solved in three steps. The initial set of resources that can be allocated to each active CUs is determined in the first step. In the second step, it finds the set of active CUs which needs D2D assistance and then it finds suitable D2D relay nodes (DRNs). Resource allocation to those DRNs and D2D pairs without degrading the link throughput of active CUs is performed in the third step. Numerical results shows significant amount of throughput gain for the active CUs using D2D communication. We also measure the performance of our proposed model in terms of churn rate and the number of excess resource blocks (RBs) in the system.
2013 27th International Conference on Advanced Information Networking and Applications Workshops, 2013
In this paper we propose a redeployment scheme of Wireless Sensor Network (WSN) nodes based on a ... more In this paper we propose a redeployment scheme of Wireless Sensor Network (WSN) nodes based on a stochastic process. WSN suffers from formation of hole in the network due to its asymmetric deployment, unbalanced energy consumption and intentional destruction of nodes in the network. The dynamic increase in Quality-of-Service (QoS) parameters such as coverage and connectivity also may lead to formation of holes which in turn degrades the performance of the network. Therefore, in order to maintain a desired QoS, a sensor redeployment scheme is important in WSN. During its lifecycle, a sensor node experiences active, sleep, diagnose, vulnerable, repair, and fail states. We analyze the Markov process and obtain the steady state probabilities for all the states. The availability of the nodes is presented with the help of SHARPE tool. Our work utilizes Discrete-Time Markov Chain and a Semi-Markov Process to illustrate the probabilities of WSN node in various states. The required redeploym...
TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON)
A wireless sensor network consists of a large number of low-powered, short-lived, unreliable sens... more A wireless sensor network consists of a large number of low-powered, short-lived, unreliable sensors. One major challenge is to extend the network lifetime as well as ensure network coverage. In this paper, we present a novel probabilistic method for node scheduling with the goal of increasing network lifetime while maintaining network coverage. The method exploits redundancy of sensor nodes inherent in a dense sensor network while maintaining low communication overhead. We also introduce the concept of variable coverage level to cater to different coverage requirements of varied application scenarios. Simulation results show the validity of the proposed approach.
Placements of Road Side Units (RSUs) are an important issue of vehicular networks in urban areas.... more Placements of Road Side Units (RSUs) are an important issue of vehicular networks in urban areas. The merged cost of procurement, installation, and maintenance of intelligent RSUs is high, and therefore, cost-effective deployment strategies are necessary. In this article, we propose a scheme that optimally deploys intelligent roadside units using a travel matrix scheme based on the classical delta strategy where urban vehicles are involved in RSUs communication in the course of their travel times. Four (4) vehicular communication modes are studied, namely, (a) travel matrix based on delta RSUs deployment communication, (b) road intersection-based RSUs deployment communication, (c) road segmentation, and (d) free vehicle-to-vehicle communication. A baseline algorithm is suggested to determine the optimal locations of RSUs in terms of their geographical positions. A travel matrix technique is proposed to trace vehicles’ routeways and travel times in some points of interest (POI). Our ...
5G multimedia mobile wireless network is designed to support on-demand encoding of rich mobile mu... more 5G multimedia mobile wireless network is designed to support on-demand encoding of rich mobile multimedia content for heterogeneous users. Due to the heterogeneity of the users, adaptive multimedia services are essential to provide a satisfactory Quality of Experience (QoE). In this paper, we propose a utility-based dynamic adaptive multimedia streaming scheme, named UDAS, for heterogeneous users that helps in extending the battery life of the low-battery users and also uses the bandwidth of the wireless channel efficiently. At each scheduling interval, the adaptation algorithm considers four utility functions of the user devices, namely, quality utility, power consumption utility, packet error ratio utility, and remaining battery utility to adapt the data rate dynamically. We formulate an optimization problem to maximize a joint utility function of these four utilities. The solution of the problem provides the best adaptive multimedia content that is selected for transmission to the end-users in every scheduling interval. The mobile edge computing (MEC) server situated at the base station performs an on-demand HEVC (high efficiency video coding) encoding of videos and select the best suitable videos for different users. Simulation results verify the improved performance of UDAS in terms of saved battery energy and the number of unserved low-battery users in comparison with state-of-the-art non-adaptive multimedia streaming schemes and a popular scheme ESDOAS from the literature.
2021 International Conference on COMmunication Systems & NETworkS (COMSNETS), 2021
Intricate data processing, reliable and quick message exchanges are the primary requirements to a... more Intricate data processing, reliable and quick message exchanges are the primary requirements to actualize the next-generation vehicular network applications in smart cities. The cellular macro base stations and IEEE 802.11p based WAVE technology can offer data connectivity to low mobility users but fails to support the high data rate and low latency requirement for next-generation vehicular network applications. The mmWave beam antennas, along with the edge computing technique of the 5G ecosystem, is capable of supporting such a service demands. Therefore RSUs equipped with mmWave beam antennas can be a pragmatic solution to this problem. However, the cost-efficient deployment of mmWave enabled 5 G RSUs on a smart city under a restricted budget presents a significant challenge. We address this issue by formulating it as a Budgeted Maximum Coverage optimization to place such 5G RSUs in an urban vehicular scenario efficiently. The optimization maximizes the long term profits under the constraint of a limited budget. The problem under consideration is an NP-hard problem. Therefore, we employ two approximation algorithms. The greedy algorithm is fast and guarantees $\frac{1}{2}\left(1-\frac{1}{e}\right)$ approximation. The modified-greedy algorithm is slower but guarantees $\left(1-\frac{1}{e}\right)$ approximation. We validate the performance of our proposed scheme in an urban city with real data.
2018 3rd International Conference on Microwave and Photonics (ICMAP), 2018
The paper presents design methodologies for elastic optical networks (EONs) with due consideratio... more The paper presents design methodologies for elastic optical networks (EONs) with due considerations to the survivability against link failures and guardband-constrained spectral allocations, using ILP and heuristic algorithms. The obtained results show that, there should be a tradeoff between the number of guardband slots and the spectrum utilization in EONs. Further, a comparative study has been carried out for blocking probabilities of general (unprotected) and survivable EONs with two different protection mechanisms, with due consideration to guardband slots.
Delay Tolerant Networks (DTNs) ranging from Inter-Planetary Networks (IPN) to Vehicular Ad Hoc Ne... more Delay Tolerant Networks (DTNs) ranging from Inter-Planetary Networks (IPN) to Vehicular Ad Hoc Networks (VANETs) are receiving continuous attention in recent years. The existing protocols for DTNs have been primarily designed and analyzed under the assumption that data traffic is either Constant Bit Rate (CBR) or Poisson. It has been observed that such models are incapable of capturing the inter-arrival behavior of the present day traffic which may be bursty in nature. The traffic characteristics in todays communication networks are statistically self-similar in nature, i.e., burstiness and correlation exists over many time scales, also referred to as Long Range Dependency (LRD). In this paper we analyze the traffic characteristics in the nodes of a delay tolerant network. Self-similar traffic is generated by implementing a traffic model in the source module of DTN. It is based on the model of aggregated ON/OFF sources. A mathematical analysis is provided to elucidate the cause of self similar nature of traffic in DTN. Through simulations and statistical analysis of the traffic data, we study the degree of selfsimilarity of traffic in the nodes of a vehicular delay tolerant network.
In this work, we have aimed at developing a new source location privacy preserving protocols to a... more In this work, we have aimed at developing a new source location privacy preserving protocols to achieve uniform privacy privacy irrespective of the location of the source in the network with enhanced privacy and network lifetime. This is done without the use of fake packets and fake source. The proposed technique falls under the category of Phantom-based Random Walk Technicues.
In this paper, we investigate an application of the Chinese Remainder Theorem (CRT) for a novel p... more In this paper, we investigate an application of the Chinese Remainder Theorem (CRT) for a novel privacy preserving routing technique in wireless sensor networks (WSNs). The distinctive nature of the proposed technique is gathering the data, aggregating and then slicing the aggregate using t-out-of-n secret sharing scheme (based on CRT) and then route the packets to the sink via multiple paths. The sink will recover the final aggregate with just t shares using CRT. The multi-objective of the proposed technique is to provide data privacy, identity privacy, source location privacy, and route privacy. The solution also mitigates the problem of packet losses associated with the unreliable wireless communication medium by improving the reliability. We also propose an enhanced privacy preserving routing technique that achieves network wide routing paths, and overcomes the drawback of existing phantom single-path routing (PSPR) and forward random walk-based routing (FRW) schemes. Finally, we present the details of the proposed technique with a numerical example and give its possible application for secret and dynamic routing in WSNs. We also show the simulation results to validate the proposed method and comparison with PSPR and FRW techniques demonstrates that our scheme outperforms the other two solutions.
2020 National Conference on Communications (NCC), 2020
The next generation vehicular applications in smart cities, including aided self-driving, require... more The next generation vehicular applications in smart cities, including aided self-driving, require intricate data processing and quick message exchanges. A pragmatic approach to address these requirements is to adopt the edge-computing paradigm from 5G architecture, where storage, computing, and networking resources are brought to the edge of the network, i.e., closer to the end-users. Edge nodes (EN) are geographically overlaid across a region, and therefore, the effectiveness of the vehicular applications is directly associated with the proper placement of such nodes. However, the deployment of edge nodes on the roadsides presents a challenge of cost-effectiveness. In this paper, we address the efficient deployment of a limited number of edge nodes in an urban scenario under a restricted budget. To this end, we jointly consider the structural properties of the road network using complex-network based centrality metrics and the vehicular traffic distribution to rank the candidate sites for edge node placement. Thereafter, we formulate the problem of edge node deployment as a 0–1 knapsack problem, which is a classical NP problem and provide a dynamic programming based solution to it. We evaluate the proposed method in an urban scenario with real traffic and present conclusive proof that our proposed scheme yields a practical solution to the defined problem.
Proceedings of the 21st International Conference on Distributed Computing and Networking, 2020
In the current context of the massive data traffic surge, the densification of the network seems ... more In the current context of the massive data traffic surge, the densification of the network seems to be an efficient alternative solution, which demands the installation of small cells (SCs) in the 5G networks leading to its complexity. This calls for an efficient way to manage such complex systems through centralized control and content delivery strategy to help the end-users access high data rate multimedia services quicker wherein the storage and the bandwidth resources are used more effectively. In this paper, we have proposed a cache aided content delivery strategy for the 5G heterogeneous network, where the base stations of all the SCs and the macro cell are connected to the local cache-enabled content server. Moreover, a centralized controller, having a global view of the underlying network, stands responsible for delivering the multimedia content from the local server to the requisite base stations. The strategy mentioned above is found to be a promising solution resulting in the perception of seamless connectivity, thereby improving the QoE (Quality of Experience) of multimedia services. The proposed Network Selection and Resource Allocation (NSRA) strategy are observed to provide a tradeoff between the system throughput and churn rate. Moreover, the minimum rate requirement for all served users in the system is ensured.
A novel computing paradigm, called the Internet of things emerged a few years ago. IoT is materia... more A novel computing paradigm, called the Internet of things emerged a few years ago. IoT is materialized by connecting both real and digital worlds together. The deployment of IoT in vehicular networks has introduced a new vehicular communication technology-themed vehicular internet of things (V-IoT). With the introduction of miniaturized sensors and actuators, V-IoT has demonstrated the ability to improve the level of urban transport systems through the development and deployment of low-cost but powerful technologies which seamlessly upgrade the level of smart transportation in urban environments. In this research article, we have presented the features of V-IoT that encompass both the benefits and potential challenges of the technology. Low-cost IoT prototypes have been built and tested for numerous functions in vehicular environments. The monitored parameters include air, road conditions such as traffics flow sizes, air quality, weather parameters, and signal status in terms of Rec...
Railway Bridge Health Monitoring is of prime importance as damages in bridges can lead to heavy c... more Railway Bridge Health Monitoring is of prime importance as damages in bridges can lead to heavy casualties. Hence, monitoring is necessary to provide safety services to the millions of people around the world. Recently, wireless sensor network (WSN) has come up as a promising technology for health monitoring. However, memory and energy constraints of WSN, and extracting intelligible information from signals obtained from complex bridge structures are the technical challenges in this domain. In this paper, we give a brief overview of a novel railway bridge health monitoring system using smart WSN.
In this Chapter, a software-defined network (SDN)-based framework for future smart cities has bee... more In this Chapter, a software-defined network (SDN)-based framework for future smart cities has been proposed and discussed. It also comprises a distributed addressing scheme to facilitate the allocation of addresses to devices in the smart city dynamically. The framework is dynamic and modules can be added and omitted by a centralized controlling unit without disturbing the other components of the framework and other modules may be updated accordingly. In the proposed addressing scheme, a new Internet of Things (IoT) device will receive an IP address from one of their existing neighboring peer devices. This allows devices in the city to act as a proxy and generate a set of unique IP addresses from their own IP addresses, which can then be assigned to new (joining) devices; hence, reducing addressing overhead and latency, as well as avoiding the need to send broadcast messages during the address allocation process. Thus, it achieves considerable bandwidth and energy savings for the Io...
IEEE Journal on Selected Areas in Communications, 2004
AbstractIn this paper, we present a polynomial time algorithm that gives an optimal solution to ... more AbstractIn this paper, we present a polynomial time algorithm that gives an optimal solution to the routing and wavelength assign-ment (RWA) problem in a tree topology. One of the major design issues in wavelength-division multiplexed networks is the assign-ment of the ...
2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC)
With device-to-device (D2D) based relay-assisted communications, deep faded cellular users (CUs) ... more With device-to-device (D2D) based relay-assisted communications, deep faded cellular users (CUs) get a better connectivity. The deep faded CU's achievable throughput of the link from base station (BS) to the CU is less than the rate demand from the CU (unsatisfied CUs). In this paper, we study the resource allocation problem for both CUs and D2D pairs to increase the achievable throughput. This is accomplished by reducing the difference between rate demand and rate achieved for the active CUs. The resource allocation optimization problem is solved in three steps. The initial set of resources that can be allocated to each active CUs is determined in the first step. In the second step, it finds the set of active CUs which needs D2D assistance and then it finds suitable D2D relay nodes (DRNs). Resource allocation to those DRNs and D2D pairs without degrading the link throughput of active CUs is performed in the third step. Numerical results shows significant amount of throughput gain for the active CUs using D2D communication. We also measure the performance of our proposed model in terms of churn rate and the number of excess resource blocks (RBs) in the system.
2013 27th International Conference on Advanced Information Networking and Applications Workshops, 2013
In this paper we propose a redeployment scheme of Wireless Sensor Network (WSN) nodes based on a ... more In this paper we propose a redeployment scheme of Wireless Sensor Network (WSN) nodes based on a stochastic process. WSN suffers from formation of hole in the network due to its asymmetric deployment, unbalanced energy consumption and intentional destruction of nodes in the network. The dynamic increase in Quality-of-Service (QoS) parameters such as coverage and connectivity also may lead to formation of holes which in turn degrades the performance of the network. Therefore, in order to maintain a desired QoS, a sensor redeployment scheme is important in WSN. During its lifecycle, a sensor node experiences active, sleep, diagnose, vulnerable, repair, and fail states. We analyze the Markov process and obtain the steady state probabilities for all the states. The availability of the nodes is presented with the help of SHARPE tool. Our work utilizes Discrete-Time Markov Chain and a Semi-Markov Process to illustrate the probabilities of WSN node in various states. The required redeploym...
TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON)
A wireless sensor network consists of a large number of low-powered, short-lived, unreliable sens... more A wireless sensor network consists of a large number of low-powered, short-lived, unreliable sensors. One major challenge is to extend the network lifetime as well as ensure network coverage. In this paper, we present a novel probabilistic method for node scheduling with the goal of increasing network lifetime while maintaining network coverage. The method exploits redundancy of sensor nodes inherent in a dense sensor network while maintaining low communication overhead. We also introduce the concept of variable coverage level to cater to different coverage requirements of varied application scenarios. Simulation results show the validity of the proposed approach.
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Papers by Raja Datta