With the rapid development of the fifth-generation(5 G)mobile communication technology,the application of each frequency band has reached the extreme,causing mutual interference between different modules.Hence,there i...With the rapid development of the fifth-generation(5 G)mobile communication technology,the application of each frequency band has reached the extreme,causing mutual interference between different modules.Hence,there is a requirement for detecting filtering and preventing interference.In the troposphere,over-the-horizon propagation occurs in atmospheric ducts and turbulent media.The effects of both ducting and turbulence can increase the probability of occurrence of long-distance co-channel interference(CCI),in turn,severely affecting the key performance indicators such as system access,handover and drop.In the 5 G era,to ensure communication channels and information security,CCI must be reduced.This paper introduces a scattering parabolic equation algorithm for calculating signal propagation in atmospheric ducts on irregular terrain boundaries.It combines Hitney’s radio physical optical model and Wagner’s nonuniform turbulent scattering model for calculating the tropospheric scattering in an evaporation duct or a surface-based duct.The new model proposes a tropospheric scattering parabolic equation algorithm for various tropospheric duct environments.Finally,as a specific case,the topographical boundaries between several cities in the East China Plain were considered,and the over-the-horizon propagation loss was simulated for various ducting and turbulent environments.The simulation results were used to evaluate whether CCI would occur between cities in a specific environment.展开更多
The time difference of arrival(TDOA)estimation plays a crucial role in the accurate localization of the satellite interference source.In the dual-satellites interference source localization system,the target signal fr...The time difference of arrival(TDOA)estimation plays a crucial role in the accurate localization of the satellite interference source.In the dual-satellites interference source localization system,the target signal from the adjacent satellite is likely to be interfered by the normal communication signal with the same frequency.Therefore,the signal to noise ratio(SNR)of the target signal would become too low,and the TDOA estimation through cross-correlation processing would be unreliable or even unattainable.This paper proposes a technique based on blind separation to solve the co-channel interference problem,where separation of the mixed signal can be carried out by the particle filter(PF)algorithm.The experimental results show that the proposed method could achieve more accurate TDOA estimation.The measured data obtained by using the software radio platform at 915 MHz and 2 GHz respectively verify the effectiveness of the proposed method.展开更多
In order to reduce the interference,a novel,cluster-based medium access control(MAC)protocol with load aware for VANETs is proposed in this paper.First,all vehicles on roads are grouped into stable clusters in the lig...In order to reduce the interference,a novel,cluster-based medium access control(MAC)protocol with load aware for VANETs is proposed in this paper.First,all vehicles on roads are grouped into stable clusters in the light of their direction,number of neighbors,link reliability,and traffic load.By utilizing the advantages of centralized control in software defined VANETs(SDVN),cluster stability can be maintained in real-time.Second,a contention-free MAC mechanism composed of inter-cluster multi-channel allocation and intra-cluster dynamic TDMA frame allocation is proposed to prevent co-channel interference and hidden terminal interference.Simulation results show that the proposed protocol outperforms some existing protocols in cluster stability,delivery ratio,throughput and delay performance.展开更多
As wireless data applications over cellular networks become more widespread, the pressure to increase capacity will become even more intense. Capacity in the 800 and 900 MHz bands, where bandwidth is restricted, is al...As wireless data applications over cellular networks become more widespread, the pressure to increase capacity will become even more intense. Capacity in the 800 and 900 MHz bands, where bandwidth is restricted, is already becoming a limiting factor. This paper attempts to address how the application of smart antenna systems has brought about improvements in call quality and increased capacity through reduced Interference in Mobile Communication. The smart antenna may be in a variety of ways to improve the performance of a communications system. Perhaps most importantly is its capability to cancel co-channel interference. It helps in improving the system performance by increasing the channel capacity, spectrum efficiency, extending range coverage, speech quality, enabling tighter reuse of frequencies within a cellular network and economically, feasible increased signal gain, greater, reduced multipath reflection. It has been argued that Smart antennas and the Algorithms to control them are vital to a high-capacity communication system development.展开更多
Orthogonal space-time block codes (OSTBCs) are an efficient mean in order to exploit the diversity offered by the wireless multiple-input multiple-output (MIMO) channel. This paper considers capacity problems of O...Orthogonal space-time block codes (OSTBCs) are an efficient mean in order to exploit the diversity offered by the wireless multiple-input multiple-output (MIMO) channel. This paper considers capacity problems of OSTBCs over spatially correlated multiple-input single-out (MISO) Rayleigh fading channels in the presence of spatially correlated Rayleigh co-channel interference and additive Gaussian noise, and derives exact expressions of the ergodic capacity and outage probability (capacity distribution) for such OSTBCs. Some numerical examples are given to illustrate the effect of co-channel interference on the ergodic and outage capacity of OSTBCs.展开更多
Focusing on space-time block code (STBC) systems with unknown co-channel interference, an oblique projection-based robust linear receiver is proposed in this paper.Based on the oblique projection, the desired signal...Focusing on space-time block code (STBC) systems with unknown co-channel interference, an oblique projection-based robust linear receiver is proposed in this paper.Based on the oblique projection, the desired signal subspace and interference-plus-noise subspace are first identified from the received signal.Then the matched filter receiver is used to decode the STBC encoded signals in the desired signal subspace.Simulation results show that the proposed linear receiver obtains significant performance improvement over conventional Capon-type receivers under finite sample-size situations and in the presence of channel estimation errors.展开更多
Most current Global System for Mobile Communications (GSM) frequency planning methods evaluate the interference and assign frequencies based on measurement reports. Assigning the same or adjacent frequencies to cell...Most current Global System for Mobile Communications (GSM) frequency planning methods evaluate the interference and assign frequencies based on measurement reports. Assigning the same or adjacent frequencies to cells close to each other will introduce co-channel and adjacent channel interference which will reduce network performance. Traditionally, man power is used to check and allocate new frequencies which is time consuming and the accuracy is not satisfactory. This paper presents an intelligent analysis method for optimization of co-channel and adjacent channel interference by exploiting cell configuration information. The method defines an interference evaluation model by analyzing various factors such as the base station layer, the azimuth ward relationship, and the cell neighborhood relationships. The interference for each frequency is evaluated and the problem frequencies are optimized. This method is verified by a large number of actual datasets from an in-service GSM network. The results show this method has better intelligence, accuracy, timeliness, and visualization than traditional methods.展开更多
Heterogeneous network (Het-Net) is part of the long-term evolution advanced (LTE-A) study item and represents cellular deployments with a mixture of cells of different overlapping coverage areas, e.g., a number of...Heterogeneous network (Het-Net) is part of the long-term evolution advanced (LTE-A) study item and represents cellular deployments with a mixture of cells of different overlapping coverage areas, e.g., a number of relay and pico cells overlaid by a macro cell in the same frequency. Traffic balancing and interference management are required in Het-Net design for LTE-A to maintain system performance. In this paper, we propose an inter-domain cooperative traffic balancing scheme focusing on reducing the effective resource cost and mitigating the co-channel interference in multi-domain Het-Net. We first set up the conception of multi-domain in Het-Net and incorporate the co-channel interference into the proposed traffic balancing scheme. Then we model the traffic balancing issue as a multi-domain traffic resource optimization problem for minimizing the effective resource cost. The detailed implementation for the proposed traffic balancing scheme is designed. In the numerical evaluation, the genetic algorithm (GA) as an optimization method is used to demonstrate that the total effective resource cost is significantly reduced through our proposed inter-domain traffic balancing scheme, comparing with the intra-domain traffic balancing scheme. The 43% of the resource cost is saved. In the system level simulation, the performance results of signal interference noise ratio (SINR) and throughput demonstrate that the proposed scheme has great advantages in interference management in Het-Net.展开更多
目的甘丙肽受体1(galanin receptor 1,GALR1)信号通路在痛觉调节中发挥重要作用,该研究利用坐骨神经慢性压迫(chronic constriction injury of the sciatic nerve,CCI)大鼠模型,探索慢病毒介导的DREAM沉默治疗在CCI模型大鼠疼痛中的作...目的甘丙肽受体1(galanin receptor 1,GALR1)信号通路在痛觉调节中发挥重要作用,该研究利用坐骨神经慢性压迫(chronic constriction injury of the sciatic nerve,CCI)大鼠模型,探索慢病毒介导的DREAM沉默治疗在CCI模型大鼠疼痛中的作用及其对GALR1的表达调控。方法选择健康雄性SD大鼠24只,随机分为4组(n=6):即RNA干扰组、空白载体组、单纯CCI组和正常对照组。鞘内置管前后分别测定基础痛阈,RNA干扰组和空白载体组于CCI后经微导管给予pKCSHR-Puro/GFP-DREAM慢病毒和空白载体,并测定腰段脊髓内下游调控元件拮抗分子(downstream regulatory element antagonist,DREAM)和GALR1的蛋白表达。结果大鼠痛阈的变化:手术同侧热痛阈和机械痛阈测定结果表明,CCI处理后,RNA干扰组、空白载体组及单纯CCI组在各个时间点热痛阈和机械痛阈较正常对照组均显著降低(P<0.01);RNA干扰组鞘内注射后较注射前痛阈显著升高,治疗后相同时间点RNA干扰组较空白载体组及单纯CCI组痛阈亦显著升高。Western blotting结果表明,与其他实验组对比,RNA干扰组的DREAM蛋白表达水平显著下调,而GALR1蛋白表达水平较空白载体组、单纯CCI组亦有显著下调。结论 DREAM可以调控GALR1的表达,提示甘丙肽受体1信号通路参与DREAM基因调节大鼠神经病理性疼痛。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62005205,62071359,and 61775175)Natural Science Basic Research Program of Shaanxi,China(Grant No.2020JQ-331)。
文摘With the rapid development of the fifth-generation(5 G)mobile communication technology,the application of each frequency band has reached the extreme,causing mutual interference between different modules.Hence,there is a requirement for detecting filtering and preventing interference.In the troposphere,over-the-horizon propagation occurs in atmospheric ducts and turbulent media.The effects of both ducting and turbulence can increase the probability of occurrence of long-distance co-channel interference(CCI),in turn,severely affecting the key performance indicators such as system access,handover and drop.In the 5 G era,to ensure communication channels and information security,CCI must be reduced.This paper introduces a scattering parabolic equation algorithm for calculating signal propagation in atmospheric ducts on irregular terrain boundaries.It combines Hitney’s radio physical optical model and Wagner’s nonuniform turbulent scattering model for calculating the tropospheric scattering in an evaporation duct or a surface-based duct.The new model proposes a tropospheric scattering parabolic equation algorithm for various tropospheric duct environments.Finally,as a specific case,the topographical boundaries between several cities in the East China Plain were considered,and the over-the-horizon propagation loss was simulated for various ducting and turbulent environments.The simulation results were used to evaluate whether CCI would occur between cities in a specific environment.
基金supported by the Fundamental Research Funds for the Central Universities(2082604194194)
文摘The time difference of arrival(TDOA)estimation plays a crucial role in the accurate localization of the satellite interference source.In the dual-satellites interference source localization system,the target signal from the adjacent satellite is likely to be interfered by the normal communication signal with the same frequency.Therefore,the signal to noise ratio(SNR)of the target signal would become too low,and the TDOA estimation through cross-correlation processing would be unreliable or even unattainable.This paper proposes a technique based on blind separation to solve the co-channel interference problem,where separation of the mixed signal can be carried out by the particle filter(PF)algorithm.The experimental results show that the proposed method could achieve more accurate TDOA estimation.The measured data obtained by using the software radio platform at 915 MHz and 2 GHz respectively verify the effectiveness of the proposed method.
文摘In order to reduce the interference,a novel,cluster-based medium access control(MAC)protocol with load aware for VANETs is proposed in this paper.First,all vehicles on roads are grouped into stable clusters in the light of their direction,number of neighbors,link reliability,and traffic load.By utilizing the advantages of centralized control in software defined VANETs(SDVN),cluster stability can be maintained in real-time.Second,a contention-free MAC mechanism composed of inter-cluster multi-channel allocation and intra-cluster dynamic TDMA frame allocation is proposed to prevent co-channel interference and hidden terminal interference.Simulation results show that the proposed protocol outperforms some existing protocols in cluster stability,delivery ratio,throughput and delay performance.
文摘As wireless data applications over cellular networks become more widespread, the pressure to increase capacity will become even more intense. Capacity in the 800 and 900 MHz bands, where bandwidth is restricted, is already becoming a limiting factor. This paper attempts to address how the application of smart antenna systems has brought about improvements in call quality and increased capacity through reduced Interference in Mobile Communication. The smart antenna may be in a variety of ways to improve the performance of a communications system. Perhaps most importantly is its capability to cancel co-channel interference. It helps in improving the system performance by increasing the channel capacity, spectrum efficiency, extending range coverage, speech quality, enabling tighter reuse of frequencies within a cellular network and economically, feasible increased signal gain, greater, reduced multipath reflection. It has been argued that Smart antennas and the Algorithms to control them are vital to a high-capacity communication system development.
基金the National Natural Science Foundation of China (Grant No. 60672030)the Open Research Fund of National Mobile Communications Research Laboratory of Southeast University (Grant No. W200810)
文摘Orthogonal space-time block codes (OSTBCs) are an efficient mean in order to exploit the diversity offered by the wireless multiple-input multiple-output (MIMO) channel. This paper considers capacity problems of OSTBCs over spatially correlated multiple-input single-out (MISO) Rayleigh fading channels in the presence of spatially correlated Rayleigh co-channel interference and additive Gaussian noise, and derives exact expressions of the ergodic capacity and outage probability (capacity distribution) for such OSTBCs. Some numerical examples are given to illustrate the effect of co-channel interference on the ergodic and outage capacity of OSTBCs.
基金Supported partially by the National Natural Science Foundation of China (Grant Nos 60572046, 60502022, 60772095)the National High-Tech Research & Development Program of China (Grant No 2006AA01Z220)
文摘Focusing on space-time block code (STBC) systems with unknown co-channel interference, an oblique projection-based robust linear receiver is proposed in this paper.Based on the oblique projection, the desired signal subspace and interference-plus-noise subspace are first identified from the received signal.Then the matched filter receiver is used to decode the STBC encoded signals in the desired signal subspace.Simulation results show that the proposed linear receiver obtains significant performance improvement over conventional Capon-type receivers under finite sample-size situations and in the presence of channel estimation errors.
基金Supported by the National Key Projects of Science and Technology of China (No. 2010ZX03005-003)
文摘Most current Global System for Mobile Communications (GSM) frequency planning methods evaluate the interference and assign frequencies based on measurement reports. Assigning the same or adjacent frequencies to cells close to each other will introduce co-channel and adjacent channel interference which will reduce network performance. Traditionally, man power is used to check and allocate new frequencies which is time consuming and the accuracy is not satisfactory. This paper presents an intelligent analysis method for optimization of co-channel and adjacent channel interference by exploiting cell configuration information. The method defines an interference evaluation model by analyzing various factors such as the base station layer, the azimuth ward relationship, and the cell neighborhood relationships. The interference for each frequency is evaluated and the problem frequencies are optimized. This method is verified by a large number of actual datasets from an in-service GSM network. The results show this method has better intelligence, accuracy, timeliness, and visualization than traditional methods.
基金supported by the National Natural Science Foundation of China (60961004/F0104)
文摘Heterogeneous network (Het-Net) is part of the long-term evolution advanced (LTE-A) study item and represents cellular deployments with a mixture of cells of different overlapping coverage areas, e.g., a number of relay and pico cells overlaid by a macro cell in the same frequency. Traffic balancing and interference management are required in Het-Net design for LTE-A to maintain system performance. In this paper, we propose an inter-domain cooperative traffic balancing scheme focusing on reducing the effective resource cost and mitigating the co-channel interference in multi-domain Het-Net. We first set up the conception of multi-domain in Het-Net and incorporate the co-channel interference into the proposed traffic balancing scheme. Then we model the traffic balancing issue as a multi-domain traffic resource optimization problem for minimizing the effective resource cost. The detailed implementation for the proposed traffic balancing scheme is designed. In the numerical evaluation, the genetic algorithm (GA) as an optimization method is used to demonstrate that the total effective resource cost is significantly reduced through our proposed inter-domain traffic balancing scheme, comparing with the intra-domain traffic balancing scheme. The 43% of the resource cost is saved. In the system level simulation, the performance results of signal interference noise ratio (SINR) and throughput demonstrate that the proposed scheme has great advantages in interference management in Het-Net.
文摘目的甘丙肽受体1(galanin receptor 1,GALR1)信号通路在痛觉调节中发挥重要作用,该研究利用坐骨神经慢性压迫(chronic constriction injury of the sciatic nerve,CCI)大鼠模型,探索慢病毒介导的DREAM沉默治疗在CCI模型大鼠疼痛中的作用及其对GALR1的表达调控。方法选择健康雄性SD大鼠24只,随机分为4组(n=6):即RNA干扰组、空白载体组、单纯CCI组和正常对照组。鞘内置管前后分别测定基础痛阈,RNA干扰组和空白载体组于CCI后经微导管给予pKCSHR-Puro/GFP-DREAM慢病毒和空白载体,并测定腰段脊髓内下游调控元件拮抗分子(downstream regulatory element antagonist,DREAM)和GALR1的蛋白表达。结果大鼠痛阈的变化:手术同侧热痛阈和机械痛阈测定结果表明,CCI处理后,RNA干扰组、空白载体组及单纯CCI组在各个时间点热痛阈和机械痛阈较正常对照组均显著降低(P<0.01);RNA干扰组鞘内注射后较注射前痛阈显著升高,治疗后相同时间点RNA干扰组较空白载体组及单纯CCI组痛阈亦显著升高。Western blotting结果表明,与其他实验组对比,RNA干扰组的DREAM蛋白表达水平显著下调,而GALR1蛋白表达水平较空白载体组、单纯CCI组亦有显著下调。结论 DREAM可以调控GALR1的表达,提示甘丙肽受体1信号通路参与DREAM基因调节大鼠神经病理性疼痛。