Machine-to-machine (M2M) communication plays a fundamental role in autonomous IoT (Internet of Things)-based infrastructure, a vital part of the fourth industrial revolution. Machine-type communication devices(MTCDs) ...Machine-to-machine (M2M) communication plays a fundamental role in autonomous IoT (Internet of Things)-based infrastructure, a vital part of the fourth industrial revolution. Machine-type communication devices(MTCDs) regularly share extensive data without human intervention while making all types of decisions. Thesedecisions may involve controlling sensitive ventilation systems maintaining uniform temperature, live heartbeatmonitoring, and several different alert systems. Many of these devices simultaneously share data to form anautomated system. The data shared between machine-type communication devices (MTCDs) is prone to risk dueto limited computational power, internal memory, and energy capacity. Therefore, securing the data and devicesbecomes challenging due to factors such as dynamic operational environments, remoteness, harsh conditions,and areas where human physical access is difficult. One of the crucial parts of securing MTCDs and data isauthentication, where each devicemust be verified before data transmission. SeveralM2Mauthentication schemeshave been proposed in the literature, however, the literature lacks a comprehensive overview of current M2Mauthentication techniques and the challenges associated with them. To utilize a suitable authentication schemefor specific scenarios, it is important to understand the challenges associated with it. Therefore, this article fillsthis gap by reviewing the state-of-the-art research on authentication schemes in MTCDs specifically concerningapplication categories, security provisions, and performance efficiency.展开更多
Many Internet of Things(IoT)systems are based on the intercommunication among different devices and centralized systems.Nowadays,there are several commercial and research platforms available to simplify the creation o...Many Internet of Things(IoT)systems are based on the intercommunication among different devices and centralized systems.Nowadays,there are several commercial and research platforms available to simplify the creation of such IoT systems.However,developing these systems can often be a tedious task.To address this challenge,a proposed solution involves the implementation of a unified program or script that encompasses the entire system,including IoT devices functionality.This approach is based on an abstraction,integrating the control of the devices in a single program through a programmable object.Subsequently,the proposal processes the unified script to generate the centralized system code and a controller for each device.By adopting this approach,developers will be able to create IoT systems with significantly reduced implementation costs,surpassing current platforms by more than 10%.The results demonstrate that the single program approach can significantly accelerate the development of IoT systems relying on device communication.展开更多
In order to solve the problem of inter-vehicle communication (IVC) in vast and desolate areas such as the desert and the Gobi, two vehicle network models are proposed. One is based on satellite communication and the...In order to solve the problem of inter-vehicle communication (IVC) in vast and desolate areas such as the desert and the Gobi, two vehicle network models are proposed. One is based on satellite communication and the other is based on high altitude platform ( HAP ) communication. The system outline and networking modes of the two models are described. In the satellite communication based model, all the vehicles are equipped with vehicle-bone satellite communication on the move terminals and the communication signals between vehicles are forwarded by satellite. In the high altitude platform-based model, the HAPs are equipped with base station facilities to form aerial base stations, and vehicles can communicate with each other via common terrestrial mobile communication devices. Some key parameters such as path loss, link loss and system capacity are also computed. The analysis shows that both the two models can satisfy the requirement of IVC in the descriptive environment.展开更多
With the popularity of green computing and the huge usage of networks,there is an acute need for expansion of the 5G network.5G is used where energy efficiency is the highest priority,and it can play a pinnacle role i...With the popularity of green computing and the huge usage of networks,there is an acute need for expansion of the 5G network.5G is used where energy efficiency is the highest priority,and it can play a pinnacle role in helping every industry to hit sustainability.While in the 5G network,conventional performance guides,such as network capacity and coverage are still major issues and need improvements.Device to Device communication(D2D)communication technology plays an important role to improve the capacity and coverage of 5G technology using different techniques.The issue of energy utilization in the IoT based system is a significant exploration center.Energy optimizationin D2D communication is an important point.We need to resolve this issue for increasing system performance.Green IoT speaks to the issue of lessening energy utilization of IoT gadgets which accomplishes a supportable climate for IoT systems.In this paper,we improve the capacity and coverage of 5G technology using Multiple Inputs Multiple Outputs(MU-MIMO).MUMIMO increases the capacity of 5G in D2D communication.We also present all the problems faced by 5G technology and proposed architecture to enhance system performance.展开更多
Radio-frequency(RF)micro-electro-mechanical-system(MEMS)switches are widely used in communication devices and test instruments.In this paper,we demonstrate the structural design and optimization of a novel RF MEMS swi...Radio-frequency(RF)micro-electro-mechanical-system(MEMS)switches are widely used in communication devices and test instruments.In this paper,we demonstrate the structural design and optimization of a novel RF MEMS switch with a straight top electrode.The insertion loss,isolation,actuator voltage,and stress distribution of the switch are optimized and explored simultaneously by HFSS and COMSOL software,taking into account both its RF and mechanical properties.Based on the optimized results,a switch was fabricated by a micromachining process compatible with conventional IC processes.The RF performance in the DC to 18 GHz range was measured with a vector network analyzer,showing isolation of more than 21.28 dB over the entire operating frequency range.Moreover,the required actuation voltage was about 9.9 V,and the switching time was approximately 33μs.A maximum lifetime of 109 switching cycles was obtained.Additionally,the dimension of the sample is 1.8 mm×1.8 mm×0.3 mm,which might find application in the current stage.展开更多
This paper presents a novel in-plane photonic crystal channel drop filter. The device is composed of a resonant cavity sandwiched by two parallel waveguides. The cavity has two resonant modes with opposite symmetries....This paper presents a novel in-plane photonic crystal channel drop filter. The device is composed of a resonant cavity sandwiched by two parallel waveguides. The cavity has two resonant modes with opposite symmetries. Tuning these two modes into degeneracy causes destructive interference in bus waveguide, which results in high forward drop efficiency at the resonant wavelength. From the result of numerical analysis by using two-dimensional finite-difference time-domain method, the channel drop filter has a drop efficiency of 96% and a Q value of over 3000, which can be used in dense wavelength division multiplexing systems.展开更多
This paper proposes and simulates a novel all-optical error-bit amplitude monitor based on cross-gain modulation and four-wave mixing in cascaded semiconductor optical amplifiers (SOAs), which function as logic NOT ...This paper proposes and simulates a novel all-optical error-bit amplitude monitor based on cross-gain modulation and four-wave mixing in cascaded semiconductor optical amplifiers (SOAs), which function as logic NOT and logic AND, respectively. The proposed scheme is successfully simulated for 40 Gb/s return-to-zero (RZ) signal with different duty cycles. In the first stage, the SOA is followed by a detuning filter to accelerate the gain recovery as well as improve the extinction ratio. A clock probe signal is used to avoid the edge pulse-pairs in the output waveform. Among these RZ formats, 33% RZ format is preferred to obtain the largest eye opening. The normalized error amplitude, defined as error bit amplitude over the standard mark amplitude, has a dynamic range from 0.1 to 0.65 for all RZ formats. The simulations show small input power dynamic range because of the nonlinear gain variation in the first stage. This scheme is competent for nonreturn-to-zero format at 10Gb/s as well.展开更多
All-optical digital logic elementary circuits are the building blocks of many important computational operations in future high-speed all-optical networks and computing systems. Multifunetional and reconfigurable logi...All-optical digital logic elementary circuits are the building blocks of many important computational operations in future high-speed all-optical networks and computing systems. Multifunetional and reconfigurable logic units are essential in this respect. Employing the demodulation properties of delay interferometers for input differential phase shift keying signals and the gain saturation effect in two parallel semiconductor optical amplifiers, a novel design of 40 Cbit/s reconfigurable all-optical dual-directional half-subtractor is proposed and demonstrated. All output logic results show that the scheme achieves over 11=dB extinction ratio, clear and wide open eye diagram, as well as low polarization dependence (〈 1 dB), without using any additional input light beam. The scheme may provide a promising candidate for future ultrafast all-optical signal processing applications.展开更多
Wireless devicetodevice (D2D) communications sharing the spectrum of cellular networks is important for improving spec trum efficiency. Furthermore, introducing multicast and multi hop communications to D2D networks...Wireless devicetodevice (D2D) communications sharing the spectrum of cellular networks is important for improving spec trum efficiency. Furthermore, introducing multicast and multi hop communications to D2D networks can expand D2D ser vice functions. In this paper, we propose an anglebased inter ferenceaware routing algorithm for D2D multicast communica tions. This algorithm reuses the uplink cellular spectrum. Our proposed algorithm aims to reduce the outage probability and minimize the average hop count over all multicast destina tions (i.e., multicast receivers), while limiting interference to cellular users to a tolerable level. In particular, our algorithm integrates two design principles for hopbyhop route selec tion. First, we minimize the distance ratio of the candidateto destination link to the candidatetobasestation link, such that the selected route advances closer to a subset of multi cast receivers. Second, we design the anglethreshold based merging strategy to divide multicast receivers into subsets with geographically close destinations. By applying the two principles for selection of each hop and further deriving an adaptive powerallocation strategy, the message can be more effieiently delivered to destinations with fewer branches when constructing the multicast tree. This means fewer duplicated data transmissions. Analyses and simulations are presented to show the impact of system parameters on the routing perfor mances. Simulation results also demonstrate the superiority of our algorithm over baseline schemes in terms of outage proba bility and average hop count.展开更多
With progress in fabrication technology, integrated photonics plays an increasingly important role in high-speed optical communications, from monolithic transmitters and receivers for advanced optical modulation forma...With progress in fabrication technology, integrated photonics plays an increasingly important role in high-speed optical communications, from monolithic transmitters and receivers for advanced optical modulation formats to on-chip subsystems for optical signal processing. We review our recent work on the highly tailorable physical properties of silicon waveguides for communication and signal processing applications, using slot structures. Controllable chromatic dispersion, nonlinearity, and polarization properties of the waveguides are presented, and the enabled wideband wavelength conversion, optical tunable delay, and signal processing of polarization-multiplexing data channels are discussed.展开更多
Device to device(D2D) communications may generate interference to the existing cellular networks.An interference suppression(IS) scheme is proposed in this paper.With this scheme,the threshold of D2D-pairs(D2D-Ps) com...Device to device(D2D) communications may generate interference to the existing cellular networks.An interference suppression(IS) scheme is proposed in this paper.With this scheme,the threshold of D2D-pairs(D2D-Ps) communication was designed to reject the D2D-Ps which were not satisfied the threshold constraint,ensuring that the cellular users(CUs) had priority to use the spectrum resources.Then the interference from D2D-Ps at the receiver of CUs was eliminated first by precoding at the D2D transmitter and decoding at the CU's receiver.Next,the interference between D2D-Ps was suppressed by using interference alignment(IA).Performance analysis shows that the priority of CUs using the spectrum resources has been guaranteed;the interference generated on the cellular links is well eliminated;the interference between D2D-Ps can also be suppressed.展开更多
The traditional software development model commonly named “waterfall” is unable to cope with the increasing functionality and complexity of modern embedded systems. In addition, it is unable to support the ability f...The traditional software development model commonly named “waterfall” is unable to cope with the increasing functionality and complexity of modern embedded systems. In addition, it is unable to support the ability for businesses to quickly respond to new market opportunities due to changing requirements. As a response, the software development community developed the Agile Methodologies (e.g., extreme Programming, Scrum) which were also adopted by the Embedded System community. However, failures and bad experiences in applying Agile Methodologies to the development of embedded systems have not been reported in the literature. Therefore, this paper contributes a detailed account of our first-time experiences adopting an agile approach in the prototype development of a wireless environment data acquisition system in an academic environment. We successfully applied a subset of the extreme Programming (XP) methodology to our software development using the Python programming language, an experience that demonstrated its benefits in shaping the design of the software and also increasing productivity. We used an incremental development approach for the hardware components and adopted a “cumulative testing” approach. For the overall development process management, however, we concluded that the Promise/Commitment-Based Project Management (PB-PM/CBPM) was better suited. We discovered that software and hardware components of embedded systems are best developed in parallel or near-parallel. We learned that software components that pass automated tests may not survive in the tests against the hardware. Throughout this rapid prototyping effort, factors like team size and our availability as graduate students were major obstacles to fully apply the XP methodology.展开更多
Owing to advanced storage and communication capabilities today, smart devices have become the basic interface between individuals and their surrounding environment. In particular, massive devices connect to one other ...Owing to advanced storage and communication capabilities today, smart devices have become the basic interface between individuals and their surrounding environment. In particular, massive devices connect to one other directly in a proximity area, thereby enabling abundant Proximity Services(Pro Se), which can be classified into two categories: public safety communication and social discovery. However, two challenges impede the quick development and deployment of Pro Se applications. From the viewpoint of networking, no multi-hop connectivity functionality component can be directly operated on commercially off-the-shelf devices, and from the programming viewpoint, an easily reusable development framework is lacking for developers with minimal knowledge of the underlying communication technologies and connectivity. Considering these two issues, this paper makes a twofold contribution. First, a multi-hop mesh networking based on Bluetooth Low Energy(BLE) is implemented,in which a proactive routing mechanism with link-quality(i.e., received signal strength indication) assistance is designed. Second, a Pro Se development framework called BLE Mesh is designed and implemented, which can provide significant benefits for application developers, framework maintenance professionals, and end users. Rich application programming interfaces can help developers to build Pro Se apps easily and quickly. Dependency inversion principle and template method pattern allow modules in BLE Mesh to be loosely coupled and easy to maintain and update. Callback mechanism enables modules to work smoothly together and automation processes such as registration, node discovery, and messaging are employed to offer nearly zero-configuration for end users.Finally, based on the designed Pro Se development kit, a public safety communications app called Quote Send App is built to distribute emergency information in close area without Internet access. The process illustrates the easy usability of BLE Mesh to develop Pro Se apps.展开更多
Mars is one of the most valuable planets for space exploration.After entering the entry descent and landing(EDL)phase,the spacecraft would carry out a series of procedural deceleration operations and achieve soft land...Mars is one of the most valuable planets for space exploration.After entering the entry descent and landing(EDL)phase,the spacecraft would carry out a series of procedural deceleration operations and achieve soft landing on the surface of Mars.In the process of EDL,the landing platform would encounter a series of irreversible incidents within environmental unpredictability,making this process highly risky.The emergency communication device plays an important role if in the Mars Exploration Program.It can capture and store key dynamic parameters during EDL phase,enabling a high probability of survival in the occurrence of a faulty condition.It can also send the stored data to the Mars obit probe when the communication condition is met.This paper presents a scheme design for the emergency communication device based on its functionality and performance requirements.It includes the design proposal,simulation results,reliability analysis,technical risks and control measures,inheritance and performance compliance which verifies the rationality and correctness of the design.展开更多
For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digit...For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digital passive intermodulation(PIM) suppression approaches can be easily reconfigured and therefore are highly attractive for future satellite communication systems.A simplified model of nonlinear distortion from passive microwave devices is established in consideration of the memory effect.The multiple high-order PIM products falling into the receiving band can be described as a bilinear predictor function.A suppression algorithm based on a bilinear polynomial decorrelated adaptive filter is proposed for baseband digital signal processing.In consideration of the time-varying characteristics of passive intermodulation,this algorithm can achieve the rapidness of online interference estimation and low complexity with less consumption of resources.Numerical simulation results show that the algorithm can effectively compensate the passive intermodulation interference,and achieve a high signal-to-interference ratio gain.展开更多
基金the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia(Grant No.GRANT5,208).
文摘Machine-to-machine (M2M) communication plays a fundamental role in autonomous IoT (Internet of Things)-based infrastructure, a vital part of the fourth industrial revolution. Machine-type communication devices(MTCDs) regularly share extensive data without human intervention while making all types of decisions. Thesedecisions may involve controlling sensitive ventilation systems maintaining uniform temperature, live heartbeatmonitoring, and several different alert systems. Many of these devices simultaneously share data to form anautomated system. The data shared between machine-type communication devices (MTCDs) is prone to risk dueto limited computational power, internal memory, and energy capacity. Therefore, securing the data and devicesbecomes challenging due to factors such as dynamic operational environments, remoteness, harsh conditions,and areas where human physical access is difficult. One of the crucial parts of securing MTCDs and data isauthentication, where each devicemust be verified before data transmission. SeveralM2Mauthentication schemeshave been proposed in the literature, however, the literature lacks a comprehensive overview of current M2Mauthentication techniques and the challenges associated with them. To utilize a suitable authentication schemefor specific scenarios, it is important to understand the challenges associated with it. Therefore, this article fillsthis gap by reviewing the state-of-the-art research on authentication schemes in MTCDs specifically concerningapplication categories, security provisions, and performance efficiency.
文摘Many Internet of Things(IoT)systems are based on the intercommunication among different devices and centralized systems.Nowadays,there are several commercial and research platforms available to simplify the creation of such IoT systems.However,developing these systems can often be a tedious task.To address this challenge,a proposed solution involves the implementation of a unified program or script that encompasses the entire system,including IoT devices functionality.This approach is based on an abstraction,integrating the control of the devices in a single program through a programmable object.Subsequently,the proposal processes the unified script to generate the centralized system code and a controller for each device.By adopting this approach,developers will be able to create IoT systems with significantly reduced implementation costs,surpassing current platforms by more than 10%.The results demonstrate that the single program approach can significantly accelerate the development of IoT systems relying on device communication.
基金FThe National High Technology Research and Development Program of China (863 Program) (No. 2008AA01Z205)the Specialized Development Foundation for the Achievement Transformation of Jiangsu Province (No. BA2010023)+1 种基金the Natural Science Foundation of Hainan Province (No. 609008)Sanya University and Local Government Technological Cooperative Project (No. 2010YD29)
文摘In order to solve the problem of inter-vehicle communication (IVC) in vast and desolate areas such as the desert and the Gobi, two vehicle network models are proposed. One is based on satellite communication and the other is based on high altitude platform ( HAP ) communication. The system outline and networking modes of the two models are described. In the satellite communication based model, all the vehicles are equipped with vehicle-bone satellite communication on the move terminals and the communication signals between vehicles are forwarded by satellite. In the high altitude platform-based model, the HAPs are equipped with base station facilities to form aerial base stations, and vehicles can communicate with each other via common terrestrial mobile communication devices. Some key parameters such as path loss, link loss and system capacity are also computed. The analysis shows that both the two models can satisfy the requirement of IVC in the descriptive environment.
基金The authors extend their heartfelt thanks to the Department of Computer Science,College of Computer Science and Engineering,Taibah University Madinah,Saudi Arabia.
文摘With the popularity of green computing and the huge usage of networks,there is an acute need for expansion of the 5G network.5G is used where energy efficiency is the highest priority,and it can play a pinnacle role in helping every industry to hit sustainability.While in the 5G network,conventional performance guides,such as network capacity and coverage are still major issues and need improvements.Device to Device communication(D2D)communication technology plays an important role to improve the capacity and coverage of 5G technology using different techniques.The issue of energy utilization in the IoT based system is a significant exploration center.Energy optimizationin D2D communication is an important point.We need to resolve this issue for increasing system performance.Green IoT speaks to the issue of lessening energy utilization of IoT gadgets which accomplishes a supportable climate for IoT systems.In this paper,we improve the capacity and coverage of 5G technology using Multiple Inputs Multiple Outputs(MU-MIMO).MUMIMO increases the capacity of 5G in D2D communication.We also present all the problems faced by 5G technology and proposed architecture to enhance system performance.
基金supported by the Equipment Development Department of the New Product Project,the Shanxi Province Postgraduate Education Reform Project,the Double First-Class Disciplines,the National First-class Curriculum Construction,and the Province Future Technology Project (Grant Nos.2019XW0010,11012103,11012133,11013168,and 11013169).
文摘Radio-frequency(RF)micro-electro-mechanical-system(MEMS)switches are widely used in communication devices and test instruments.In this paper,we demonstrate the structural design and optimization of a novel RF MEMS switch with a straight top electrode.The insertion loss,isolation,actuator voltage,and stress distribution of the switch are optimized and explored simultaneously by HFSS and COMSOL software,taking into account both its RF and mechanical properties.Based on the optimized results,a switch was fabricated by a micromachining process compatible with conventional IC processes.The RF performance in the DC to 18 GHz range was measured with a vector network analyzer,showing isolation of more than 21.28 dB over the entire operating frequency range.Moreover,the required actuation voltage was about 9.9 V,and the switching time was approximately 33μs.A maximum lifetime of 109 switching cycles was obtained.Additionally,the dimension of the sample is 1.8 mm×1.8 mm×0.3 mm,which might find application in the current stage.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10774195,U0834001,and 10974263)the Ministry of Education,China (Grant No.309024)+1 种基金the Program for New Century Excellent Talents in University,Chinathe National Basic Research Program of China (Grant No.2010CB923201)
文摘This paper presents a novel in-plane photonic crystal channel drop filter. The device is composed of a resonant cavity sandwiched by two parallel waveguides. The cavity has two resonant modes with opposite symmetries. Tuning these two modes into degeneracy causes destructive interference in bus waveguide, which results in high forward drop efficiency at the resonant wavelength. From the result of numerical analysis by using two-dimensional finite-difference time-domain method, the channel drop filter has a drop efficiency of 96% and a Q value of over 3000, which can be used in dense wavelength division multiplexing systems.
基金Project partially supported by the National High Technology Developing Program of China (Grant No 2006AA03Z0414)the National Basic Research Program of China (Grant No 2006CB302805)+1 种基金the Science Fund for Distinguished Young Scholars of Hubei Province, China (Grant No 2006ABB017)the Program for New Century Excellent Talents in Ministry of Education of China (Grant No NCET-04-0715)
文摘This paper proposes and simulates a novel all-optical error-bit amplitude monitor based on cross-gain modulation and four-wave mixing in cascaded semiconductor optical amplifiers (SOAs), which function as logic NOT and logic AND, respectively. The proposed scheme is successfully simulated for 40 Gb/s return-to-zero (RZ) signal with different duty cycles. In the first stage, the SOA is followed by a detuning filter to accelerate the gain recovery as well as improve the extinction ratio. A clock probe signal is used to avoid the edge pulse-pairs in the output waveform. Among these RZ formats, 33% RZ format is preferred to obtain the largest eye opening. The normalized error amplitude, defined as error bit amplitude over the standard mark amplitude, has a dynamic range from 0.1 to 0.65 for all RZ formats. The simulations show small input power dynamic range because of the nonlinear gain variation in the first stage. This scheme is competent for nonreturn-to-zero format at 10Gb/s as well.
基金supported by the National Natural Science Foundation of China (Grant No.60877056)the National Basic Research Program of China (Grant No.2011CB301704)
文摘All-optical digital logic elementary circuits are the building blocks of many important computational operations in future high-speed all-optical networks and computing systems. Multifunetional and reconfigurable logic units are essential in this respect. Employing the demodulation properties of delay interferometers for input differential phase shift keying signals and the gain saturation effect in two parallel semiconductor optical amplifiers, a novel design of 40 Cbit/s reconfigurable all-optical dual-directional half-subtractor is proposed and demonstrated. All output logic results show that the scheme achieves over 11=dB extinction ratio, clear and wide open eye diagram, as well as low polarization dependence (〈 1 dB), without using any additional input light beam. The scheme may provide a promising candidate for future ultrafast all-optical signal processing applications.
基金supported by National Natural Science Foundation of China under Grant No.61102078ZTE Industry-Academic-Research Cooperation Fundsthe Fundamental Research Funds for the Central Universities
文摘Wireless devicetodevice (D2D) communications sharing the spectrum of cellular networks is important for improving spec trum efficiency. Furthermore, introducing multicast and multi hop communications to D2D networks can expand D2D ser vice functions. In this paper, we propose an anglebased inter ferenceaware routing algorithm for D2D multicast communica tions. This algorithm reuses the uplink cellular spectrum. Our proposed algorithm aims to reduce the outage probability and minimize the average hop count over all multicast destina tions (i.e., multicast receivers), while limiting interference to cellular users to a tolerable level. In particular, our algorithm integrates two design principles for hopbyhop route selec tion. First, we minimize the distance ratio of the candidateto destination link to the candidatetobasestation link, such that the selected route advances closer to a subset of multi cast receivers. Second, we design the anglethreshold based merging strategy to divide multicast receivers into subsets with geographically close destinations. By applying the two principles for selection of each hop and further deriving an adaptive powerallocation strategy, the message can be more effieiently delivered to destinations with fewer branches when constructing the multicast tree. This means fewer duplicated data transmissions. Analyses and simulations are presented to show the impact of system parameters on the routing perfor mances. Simulation results also demonstrate the superiority of our algorithm over baseline schemes in terms of outage proba bility and average hop count.
基金research work sponsored by DARPA (under contract number HR0011-09-C-0124)and HP Laboratories
文摘With progress in fabrication technology, integrated photonics plays an increasingly important role in high-speed optical communications, from monolithic transmitters and receivers for advanced optical modulation formats to on-chip subsystems for optical signal processing. We review our recent work on the highly tailorable physical properties of silicon waveguides for communication and signal processing applications, using slot structures. Controllable chromatic dispersion, nonlinearity, and polarization properties of the waveguides are presented, and the enabled wideband wavelength conversion, optical tunable delay, and signal processing of polarization-multiplexing data channels are discussed.
基金National Natural Science Foundation of China(No.61503251)
文摘Device to device(D2D) communications may generate interference to the existing cellular networks.An interference suppression(IS) scheme is proposed in this paper.With this scheme,the threshold of D2D-pairs(D2D-Ps) communication was designed to reject the D2D-Ps which were not satisfied the threshold constraint,ensuring that the cellular users(CUs) had priority to use the spectrum resources.Then the interference from D2D-Ps at the receiver of CUs was eliminated first by precoding at the D2D transmitter and decoding at the CU's receiver.Next,the interference between D2D-Ps was suppressed by using interference alignment(IA).Performance analysis shows that the priority of CUs using the spectrum resources has been guaranteed;the interference generated on the cellular links is well eliminated;the interference between D2D-Ps can also be suppressed.
文摘The traditional software development model commonly named “waterfall” is unable to cope with the increasing functionality and complexity of modern embedded systems. In addition, it is unable to support the ability for businesses to quickly respond to new market opportunities due to changing requirements. As a response, the software development community developed the Agile Methodologies (e.g., extreme Programming, Scrum) which were also adopted by the Embedded System community. However, failures and bad experiences in applying Agile Methodologies to the development of embedded systems have not been reported in the literature. Therefore, this paper contributes a detailed account of our first-time experiences adopting an agile approach in the prototype development of a wireless environment data acquisition system in an academic environment. We successfully applied a subset of the extreme Programming (XP) methodology to our software development using the Python programming language, an experience that demonstrated its benefits in shaping the design of the software and also increasing productivity. We used an incremental development approach for the hardware components and adopted a “cumulative testing” approach. For the overall development process management, however, we concluded that the Promise/Commitment-Based Project Management (PB-PM/CBPM) was better suited. We discovered that software and hardware components of embedded systems are best developed in parallel or near-parallel. We learned that software components that pass automated tests may not survive in the tests against the hardware. Throughout this rapid prototyping effort, factors like team size and our availability as graduate students were major obstacles to fully apply the XP methodology.
基金supported by the National Natural Science Foundation of China(No.61171092)Jiangsu Educational Bureau Project(No.14KJA510004)NUPTSFs(Nos.NY215177 and NY217089)
文摘Owing to advanced storage and communication capabilities today, smart devices have become the basic interface between individuals and their surrounding environment. In particular, massive devices connect to one other directly in a proximity area, thereby enabling abundant Proximity Services(Pro Se), which can be classified into two categories: public safety communication and social discovery. However, two challenges impede the quick development and deployment of Pro Se applications. From the viewpoint of networking, no multi-hop connectivity functionality component can be directly operated on commercially off-the-shelf devices, and from the programming viewpoint, an easily reusable development framework is lacking for developers with minimal knowledge of the underlying communication technologies and connectivity. Considering these two issues, this paper makes a twofold contribution. First, a multi-hop mesh networking based on Bluetooth Low Energy(BLE) is implemented,in which a proactive routing mechanism with link-quality(i.e., received signal strength indication) assistance is designed. Second, a Pro Se development framework called BLE Mesh is designed and implemented, which can provide significant benefits for application developers, framework maintenance professionals, and end users. Rich application programming interfaces can help developers to build Pro Se apps easily and quickly. Dependency inversion principle and template method pattern allow modules in BLE Mesh to be loosely coupled and easy to maintain and update. Callback mechanism enables modules to work smoothly together and automation processes such as registration, node discovery, and messaging are employed to offer nearly zero-configuration for end users.Finally, based on the designed Pro Se development kit, a public safety communications app called Quote Send App is built to distribute emergency information in close area without Internet access. The process illustrates the easy usability of BLE Mesh to develop Pro Se apps.
文摘Mars is one of the most valuable planets for space exploration.After entering the entry descent and landing(EDL)phase,the spacecraft would carry out a series of procedural deceleration operations and achieve soft landing on the surface of Mars.In the process of EDL,the landing platform would encounter a series of irreversible incidents within environmental unpredictability,making this process highly risky.The emergency communication device plays an important role if in the Mars Exploration Program.It can capture and store key dynamic parameters during EDL phase,enabling a high probability of survival in the occurrence of a faulty condition.It can also send the stored data to the Mars obit probe when the communication condition is met.This paper presents a scheme design for the emergency communication device based on its functionality and performance requirements.It includes the design proposal,simulation results,reliability analysis,technical risks and control measures,inheritance and performance compliance which verifies the rationality and correctness of the design.
基金supported by the National Natural SciencFoundation of China(Nos.U1636125,61601027)
文摘For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digital passive intermodulation(PIM) suppression approaches can be easily reconfigured and therefore are highly attractive for future satellite communication systems.A simplified model of nonlinear distortion from passive microwave devices is established in consideration of the memory effect.The multiple high-order PIM products falling into the receiving band can be described as a bilinear predictor function.A suppression algorithm based on a bilinear polynomial decorrelated adaptive filter is proposed for baseband digital signal processing.In consideration of the time-varying characteristics of passive intermodulation,this algorithm can achieve the rapidness of online interference estimation and low complexity with less consumption of resources.Numerical simulation results show that the algorithm can effectively compensate the passive intermodulation interference,and achieve a high signal-to-interference ratio gain.