OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Trans...OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.展开更多
Not only high spectral efficiency(SE)but also high energy efficiency(EE)are required for future wireless communication systems.Radio orbital angular momentum(OAM)provides a new perspective of mode multiplexing to impr...Not only high spectral efficiency(SE)but also high energy efficiency(EE)are required for future wireless communication systems.Radio orbital angular momentum(OAM)provides a new perspective of mode multiplexing to improve SE.However,there are few studies on the EE performance of OAM mode multiplexing.In this paper,we investigate the SE and EE of a misaligned uniform concentric circle array(UCCA)-based multi-carrier multimode OAM and multiple-input multiple-output(MCMM-OAM-MIMO)system in the line-ofsight(LoS)channel,in which two transceiver architectures implemented by radio frequency(RF)analog synthesis and baseband digital synthesis are considered.The distance and angle of arrival(AoA)estimation are utilized for channel estimation and signal detection,whose training overhead is much less than that of traditional MIMO systems.Simulation results validate that the UCCA-based MCMM-OAM-MIMO system is superior to conventional MIMOOFDM system in the EE and SE performances.展开更多
Orbital angular momentum(OAM)at radio frequency(RF)has attracted more and more attention as a novel approach of multiplexing a set of orthogonal OAM modes on the same frequency channel to achieve high spectral efficie...Orbital angular momentum(OAM)at radio frequency(RF)has attracted more and more attention as a novel approach of multiplexing a set of orthogonal OAM modes on the same frequency channel to achieve high spectral efficiency(SE).However,the precondition for maintaining the orthogonality among different OAM modes is perfect alignment of the transmit and receive uniform circular arrays(UCAs),which is difficult to be satisfied in practical wireless communication scenarios.Therefore,to achieve available multi-mode OAM broadband wireless communication,we first investigate the effect of oblique angles on the transmission performance of the multi-mode OAM broadband system in the non-parallel misalignment case.Then,we compare the UCA-based RF analog and baseband digital transceiver structures and corresponding beam steering schemes.Mathematical analysis and numerical simulations validate that the SE of the misaligned multi-mode OAM broadband system is quite low,while analog and digital beam steering(DBS)both can significantly improve the SE of the system.However,DBS can obtain higher SE than analog beam steering especially when the bandwidth and the number of array elements are large,which validates that the baseband digital transceiver with DBS is more suitable for multi-mode OAM broadband wireless communication systems in practice.展开更多
Orbital Angular Momentum(OAM)waves are characterized by helical wave fronts and orthogonality between different modes.Therefore,OAM waves have huge potential in improving wireless communications'channel capacity a...Orbital Angular Momentum(OAM)waves are characterized by helical wave fronts and orthogonality between different modes.Therefore,OAM waves have huge potential in improving wireless communications'channel capacity and radar imaging's resolution.Consequently,the generation and application of OAM waves have attracted a lot of attention.And many methods are proposed to generate OAM waves.Although antenna array is the most popular method of generating OAM waves,OAM waves generated by antenna array have redundant modes.However,all advantages of OAM waves are closely related to infinite OAM modes.Thus,to better apply OAM waves to wireless communications and radar,it is very important to reduce unnecessary OAM modes and improve the OAM mode purity.In order to improve the OAM mode purity,two combined antenna arrays composed of X direction antenna and Y direction antenna array are proposed in this paper.The X direction antenna array and the Y direction antenna array are supplied by the excitations with the same amplitude and fixed phase shift.The overall phase shift of the X direction antenna array isπ/2 more or less than that of the Y direction antenna array.The results of formulas and antenna models in CST show that the combined antenna arrays can generate OAM waves with less redundant modes in x component,y component and z component.Besides,the z component carries pure OAM modes.展开更多
基金High-Tech Research and DevelopmentProgram of China (No. 2003AA123310)
文摘OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.
基金supported in part by the Fundamental Research Funds for the Central Universitiesthe Innovation Fund of Xidian University。
文摘Not only high spectral efficiency(SE)but also high energy efficiency(EE)are required for future wireless communication systems.Radio orbital angular momentum(OAM)provides a new perspective of mode multiplexing to improve SE.However,there are few studies on the EE performance of OAM mode multiplexing.In this paper,we investigate the SE and EE of a misaligned uniform concentric circle array(UCCA)-based multi-carrier multimode OAM and multiple-input multiple-output(MCMM-OAM-MIMO)system in the line-ofsight(LoS)channel,in which two transceiver architectures implemented by radio frequency(RF)analog synthesis and baseband digital synthesis are considered.The distance and angle of arrival(AoA)estimation are utilized for channel estimation and signal detection,whose training overhead is much less than that of traditional MIMO systems.Simulation results validate that the UCCA-based MCMM-OAM-MIMO system is superior to conventional MIMOOFDM system in the EE and SE performances.
基金supported by the Natural Science Basic Research Program of Shaanxi(2021JZ-18)the Natural Science Foundation of Guangdong Province of China(2021A1515010812)+1 种基金the Open Research Fund of National Mobile Communications Research Laboratory,Southeast University(2021D04)the Fundamental Research Funds for Central Universities,and the Innovation Fund of Xidian University。
文摘Orbital angular momentum(OAM)at radio frequency(RF)has attracted more and more attention as a novel approach of multiplexing a set of orthogonal OAM modes on the same frequency channel to achieve high spectral efficiency(SE).However,the precondition for maintaining the orthogonality among different OAM modes is perfect alignment of the transmit and receive uniform circular arrays(UCAs),which is difficult to be satisfied in practical wireless communication scenarios.Therefore,to achieve available multi-mode OAM broadband wireless communication,we first investigate the effect of oblique angles on the transmission performance of the multi-mode OAM broadband system in the non-parallel misalignment case.Then,we compare the UCA-based RF analog and baseband digital transceiver structures and corresponding beam steering schemes.Mathematical analysis and numerical simulations validate that the SE of the misaligned multi-mode OAM broadband system is quite low,while analog and digital beam steering(DBS)both can significantly improve the SE of the system.However,DBS can obtain higher SE than analog beam steering especially when the bandwidth and the number of array elements are large,which validates that the baseband digital transceiver with DBS is more suitable for multi-mode OAM broadband wireless communication systems in practice.
基金supported by the National Science Foundation of China(NSFC 62073334).
文摘Orbital Angular Momentum(OAM)waves are characterized by helical wave fronts and orthogonality between different modes.Therefore,OAM waves have huge potential in improving wireless communications'channel capacity and radar imaging's resolution.Consequently,the generation and application of OAM waves have attracted a lot of attention.And many methods are proposed to generate OAM waves.Although antenna array is the most popular method of generating OAM waves,OAM waves generated by antenna array have redundant modes.However,all advantages of OAM waves are closely related to infinite OAM modes.Thus,to better apply OAM waves to wireless communications and radar,it is very important to reduce unnecessary OAM modes and improve the OAM mode purity.In order to improve the OAM mode purity,two combined antenna arrays composed of X direction antenna and Y direction antenna array are proposed in this paper.The X direction antenna array and the Y direction antenna array are supplied by the excitations with the same amplitude and fixed phase shift.The overall phase shift of the X direction antenna array isπ/2 more or less than that of the Y direction antenna array.The results of formulas and antenna models in CST show that the combined antenna arrays can generate OAM waves with less redundant modes in x component,y component and z component.Besides,the z component carries pure OAM modes.
