With the development of CMOS and MEMS technologies, the implementation of a large number of wireless distributed micro-sensors that can be easily and rapidly deployed to form highly redundant, self-configuring, and ad...With the development of CMOS and MEMS technologies, the implementation of a large number of wireless distributed micro-sensors that can be easily and rapidly deployed to form highly redundant, self-configuring, and ad hoc sensor networks. To facilitate ease of deployment, these sensors operate on battery for extended periods of time. A particular challenge in maintaining extended battery lifetime lies in achieving communications with low power. For better understanding of the design tradeoffs of wireless sensor network （WSN）, a more accurate energy model for wireless sensor node is proposed, and an optimal design method of energy efficient wireless sensor node is described as well. Different from power models ever shown which assume the power cost of each component in WSN node is constant, the new one takes into account the energy dissipation of circuits in practical physical layer. It shows that there are some parameters, such as data rate, carrier frequency, bandwidth, Tsw, etc, which have a significant effect on the WSN node energy consumption per useful bit （EPUB）. For a given quality specification, how energy consumption can be reduced by adjusting one or more of these parameters is shown.展开更多
Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its str...Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its striking advantage in flexibility and re-configurability.In this paper,both the advantages and challenges of GPP platform are detailed analyzed.Furthermore,both GPP based software and hardware architectures for open 5G are presented and the performances of real-time signal processing and power consumption are also evaluated.The evaluation results indicate that turbo and power consumption may be another challengeable problem should be further solved to meet the requirements of realistic deployments.展开更多
In order to support massive Machine Type Communication(mMTC) applications in future Fifth Generation(5G) systems,a key technical challenge is to design a highly effective multiple access protocol for massive connectio...In order to support massive Machine Type Communication(mMTC) applications in future Fifth Generation(5G) systems,a key technical challenge is to design a highly effective multiple access protocol for massive connection requests and huge traffic load from all kinds of smart devices,e.g.bike,watch,phone,ring,glasses,shoes,etc..To solve this hard problem in distributed scenarios with massive competing devices,this paper proposes and evaluates a Neighbor-Aware Multiple Access(NAMA) protocol,which is scalable and adaptive to different connectivity size and traffic load.By exploiting acknowledgement signals broadcasted from the neighboring devices with successful packet transmissions,NAMA is able to turn itself from a contention-based random access protocol to become a contention-free deterministic access protocol with particular transmission schedules for all neighboring devices after a short transition period.The performance of NAMA is fully evaluated from random state to deterministic state through extensive computer simulations under different network sizes and Contention Window(CW)settings.Compared with traditional IEEE802.11 Distributed Coordination Function(DCF),for a crowded network with 50 devices,NAMA can greatly improve system throughput and energy efficiency by more than 110%and210%,respectively,while reducing average access delay by 53%in the deterministic state.展开更多
Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere.Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther,i.e,hun...Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere.Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther,i.e,hundreds of kilometers.In a large-scale deployed TD-LTE(Time Division Long Term Evolution)network,atmospheric ducts cause faraway downlink wireless signals to propagate beyond the designed protection distance and interfere with local uplink signals,thus resulting in a large outage probability.In this paper,we analyze the characteristics of ADI atmospheric duct interference(Atmospheric Duct Interference)by the use of real network-side big data from the current operated TD-LTE network owned by China Mobile.The analysis results yield the time varying and directional characteristics of ADI.In addition,we proposed an SVM(Support Vector Machine)-classi er based spacial prediction method of ADI by machine learning over combination of real network-side big data and real meteorological data.Furthermore,an implementation of ADMM(Alternating Direction Methods of Multipliers)framework is proposed to implement a distributed SVM prediction scheme,which reduces data exchange among di erent regions/cities,maintains similar prediction accuracy and is thus of a more practical use to operators.展开更多
Traditional mobile communication systems mainly work on the licensed frequency band near or below 3 GHz;however,this band is becoming increasingly crowded.On the other hand,there are abundant unlicensed spectrum resou...Traditional mobile communication systems mainly work on the licensed frequency band near or below 3 GHz;however,this band is becoming increasingly crowded.On the other hand,there are abundant unlicensed spectrum resources in higher frequency bands,e.g.,6 GHz,15 GHz,and 28 GHz,and if those bands are applied,the current spectrum shortage problem could be effectively alleviated.However,the wireless channel characteristics and models are important but still unknown,and thus in this study,extensive measurements and modeling have been conducted to study the characteristics of the high-frequency 15-GHz band.Specifically,a PN(Pseudo Noise)sequence based time-domain measurement system was built and applied to measure the propagation characteristics of the LOS(Line-of-Sight)and NLOS(Non-Line-of-Sight)scenarios in an indoor corridor at 15 GHz.Then,in-depth analysis and modeling on the large-scale characteristics of wireless channels,the relationship between distance and path loss,the path loss exponent,and the shadow fading standard variance are provided.Moreover,the relationship between received power and different elevation angles was studied.In the measurement,two 25-dBi horn antennas with a 10 half-power beam width are used to change elevation angles in the transmitting terminal and azimuth angles in the receiving terminal for all measurement points.The findings and results in this work will serve as a reference and basis for future theoretical studies of the 15-GHz band.展开更多
基金the National High-Tech Research and Development Plan of China (2006AA01Z223)the China Next Generation Internet (CNGI) Plan (2005-2137).
文摘With the development of CMOS and MEMS technologies, the implementation of a large number of wireless distributed micro-sensors that can be easily and rapidly deployed to form highly redundant, self-configuring, and ad hoc sensor networks. To facilitate ease of deployment, these sensors operate on battery for extended periods of time. A particular challenge in maintaining extended battery lifetime lies in achieving communications with low power. For better understanding of the design tradeoffs of wireless sensor network （WSN）, a more accurate energy model for wireless sensor node is proposed, and an optimal design method of energy efficient wireless sensor node is described as well. Different from power models ever shown which assume the power cost of each component in WSN node is constant, the new one takes into account the energy dissipation of circuits in practical physical layer. It shows that there are some parameters, such as data rate, carrier frequency, bandwidth, Tsw, etc, which have a significant effect on the WSN node energy consumption per useful bit （EPUB）. For a given quality specification, how energy consumption can be reduced by adjusting one or more of these parameters is shown.
基金funded in part by National Natural Science Foundation of China(grant NO.61471347)National S&T Mayor Project of the Ministry of S&T of China(grant NO.2016ZX03001020-003)+1 种基金key program for international S&T Cooperation Program of China(grant NO.2014DFA11640)Shanghai Natural Science Foundation(grant NO.16ZR1435100)
文摘Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its striking advantage in flexibility and re-configurability.In this paper,both the advantages and challenges of GPP platform are detailed analyzed.Furthermore,both GPP based software and hardware architectures for open 5G are presented and the performances of real-time signal processing and power consumption are also evaluated.The evaluation results indicate that turbo and power consumption may be another challengeable problem should be further solved to meet the requirements of realistic deployments.
基金funded by the National Natural Science Foundation of China (Grant No.61231009)the National HighTech R&D Program of China(863)(Grant No.2014AA01A701)+5 种基金the National Science and Technology Major Project(Grant No. 2015ZX03001033-003)Ministry of Science and Technology International Cooperation Project(Grant No.2014DFE10160)the Science and Technology Commission of Shanghai Municipality(Grant No.14ZR1439600)the EU H2020 5G Wireless project(Grant No.641985)the EU FP7 QUICK project(Grant No. PIRSES-GA-2013-612652)the EPSRC TOUCAN project(Grant No.EP/L020009/1)
文摘In order to support massive Machine Type Communication(mMTC) applications in future Fifth Generation(5G) systems,a key technical challenge is to design a highly effective multiple access protocol for massive connection requests and huge traffic load from all kinds of smart devices,e.g.bike,watch,phone,ring,glasses,shoes,etc..To solve this hard problem in distributed scenarios with massive competing devices,this paper proposes and evaluates a Neighbor-Aware Multiple Access(NAMA) protocol,which is scalable and adaptive to different connectivity size and traffic load.By exploiting acknowledgement signals broadcasted from the neighboring devices with successful packet transmissions,NAMA is able to turn itself from a contention-based random access protocol to become a contention-free deterministic access protocol with particular transmission schedules for all neighboring devices after a short transition period.The performance of NAMA is fully evaluated from random state to deterministic state through extensive computer simulations under different network sizes and Contention Window(CW)settings.Compared with traditional IEEE802.11 Distributed Coordination Function(DCF),for a crowded network with 50 devices,NAMA can greatly improve system throughput and energy efficiency by more than 110%and210%,respectively,while reducing average access delay by 53%in the deterministic state.
基金This research is partially funded by the National Natural Science Foundation of China(Nos.61461136004,61631013)Ministry of Science and Technology International Cooperation Project(No.2014DFE10160)Shanghai Municipality of Science and Technology Commission Project(Nos.17QA1403800,17ZR1429000).
文摘Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere.Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther,i.e,hundreds of kilometers.In a large-scale deployed TD-LTE(Time Division Long Term Evolution)network,atmospheric ducts cause faraway downlink wireless signals to propagate beyond the designed protection distance and interfere with local uplink signals,thus resulting in a large outage probability.In this paper,we analyze the characteristics of ADI atmospheric duct interference(Atmospheric Duct Interference)by the use of real network-side big data from the current operated TD-LTE network owned by China Mobile.The analysis results yield the time varying and directional characteristics of ADI.In addition,we proposed an SVM(Support Vector Machine)-classi er based spacial prediction method of ADI by machine learning over combination of real network-side big data and real meteorological data.Furthermore,an implementation of ADMM(Alternating Direction Methods of Multipliers)framework is proposed to implement a distributed SVM prediction scheme,which reduces data exchange among di erent regions/cities,maintains similar prediction accuracy and is thus of a more practical use to operators.
基金supported by The National High Technology Research Development Program of China(863 Program)(No.2014AA01A706)The National Natural Science Foundation of China(No.61471346)+1 种基金The National Science and Technology Major Project(No.2014ZX03003012)The Science and Technology Commission of Shanghai Municipality(No.14DZ2281000).
文摘Traditional mobile communication systems mainly work on the licensed frequency band near or below 3 GHz;however,this band is becoming increasingly crowded.On the other hand,there are abundant unlicensed spectrum resources in higher frequency bands,e.g.,6 GHz,15 GHz,and 28 GHz,and if those bands are applied,the current spectrum shortage problem could be effectively alleviated.However,the wireless channel characteristics and models are important but still unknown,and thus in this study,extensive measurements and modeling have been conducted to study the characteristics of the high-frequency 15-GHz band.Specifically,a PN(Pseudo Noise)sequence based time-domain measurement system was built and applied to measure the propagation characteristics of the LOS(Line-of-Sight)and NLOS(Non-Line-of-Sight)scenarios in an indoor corridor at 15 GHz.Then,in-depth analysis and modeling on the large-scale characteristics of wireless channels,the relationship between distance and path loss,the path loss exponent,and the shadow fading standard variance are provided.Moreover,the relationship between received power and different elevation angles was studied.In the measurement,two 25-dBi horn antennas with a 10 half-power beam width are used to change elevation angles in the transmitting terminal and azimuth angles in the receiving terminal for all measurement points.The findings and results in this work will serve as a reference and basis for future theoretical studies of the 15-GHz band.
