This paper investigates a Multiple-Input Multiple-Output (MIMO) scheme combining Transmit Antenna Selection and receive Maximal-Ratio Combining (TAS/MRC) in time-varying Rayleigh fading channels. We first present new ...This paper investigates a Multiple-Input Multiple-Output (MIMO) scheme combining Transmit Antenna Selection and receive Maximal-Ratio Combining (TAS/MRC) in time-varying Rayleigh fading channels. We first present new closed-form expressions for optimal received Signal-to-Noise Ratio (SNR),which is expressed in polynomial form. These are used to analyze ergodic capacity,outage probability and Bit Error Rate (BER) of TAS/MRC systems. Numerical results are presented to validate the theoretical analysis.展开更多
Investigations are directed to the development of high-power sources ofUWB （ultrawideband） radiation based on excitation of anterma arrays with bipolar voltage pulses. In the previously designed high-power UWB sourc...Investigations are directed to the development of high-power sources ofUWB （ultrawideband） radiation based on excitation of anterma arrays with bipolar voltage pulses. In the previously designed high-power UWB sources only one bipolar pulse former and different feeder systems for pulse distribution through the array elements were used. By means of this approach, a number of UWB sources were created with the bipolar voltage pulse length ranging from 0.2 to 2 ns and effective potential of radiation ranging from 0.4 to 3 MV. The approach has got a restriction related to the electrical breakdown in a bipolar voltage pulse former. A new approach to the creation of high-power UWB sources based on a multicharmel bipolar pulse former is suggested： the number of bipolar pulse formers is equal to the number of antennas in the array. The main problem in realization of this approach is a stable operation of bipolar pulse formers in order to ensure a coherent summation of radiated pulses in the far-field zone. The result of this work is the instability of-150 ps at the pulse length of 3 ns obtained in a one-channel bipolar pulse former indicating that the suggested approach is realizable.展开更多
随着5G时代的到来,各地5G基站的建设如火如荼,同时5G网络建设存在工程投资大、5G天线部署需要关注覆盖性能及部署周期等问题。文章针对在利旧基站建设过程中存在的天面空间受限、5G低挂高、铁塔风荷载受限等问题,对A+P(Combination of a...随着5G时代的到来,各地5G基站的建设如火如荼,同时5G网络建设存在工程投资大、5G天线部署需要关注覆盖性能及部署周期等问题。文章针对在利旧基站建设过程中存在的天面空间受限、5G低挂高、铁塔风荷载受限等问题,对A+P(Combination of active and passive antennas)一体化设备在中国电信和中国联通的5G基站建设中的使用方式提出一些建议,根据A+P设备在不同建设场景来进行工程建设、投资分析,说明A+P一体化设备的较高实用性。展开更多
文摘This paper investigates a Multiple-Input Multiple-Output (MIMO) scheme combining Transmit Antenna Selection and receive Maximal-Ratio Combining (TAS/MRC) in time-varying Rayleigh fading channels. We first present new closed-form expressions for optimal received Signal-to-Noise Ratio (SNR),which is expressed in polynomial form. These are used to analyze ergodic capacity,outage probability and Bit Error Rate (BER) of TAS/MRC systems. Numerical results are presented to validate the theoretical analysis.
文摘Investigations are directed to the development of high-power sources ofUWB （ultrawideband） radiation based on excitation of anterma arrays with bipolar voltage pulses. In the previously designed high-power UWB sources only one bipolar pulse former and different feeder systems for pulse distribution through the array elements were used. By means of this approach, a number of UWB sources were created with the bipolar voltage pulse length ranging from 0.2 to 2 ns and effective potential of radiation ranging from 0.4 to 3 MV. The approach has got a restriction related to the electrical breakdown in a bipolar voltage pulse former. A new approach to the creation of high-power UWB sources based on a multicharmel bipolar pulse former is suggested： the number of bipolar pulse formers is equal to the number of antennas in the array. The main problem in realization of this approach is a stable operation of bipolar pulse formers in order to ensure a coherent summation of radiated pulses in the far-field zone. The result of this work is the instability of-150 ps at the pulse length of 3 ns obtained in a one-channel bipolar pulse former indicating that the suggested approach is realizable.
文摘随着5G时代的到来,各地5G基站的建设如火如荼,同时5G网络建设存在工程投资大、5G天线部署需要关注覆盖性能及部署周期等问题。文章针对在利旧基站建设过程中存在的天面空间受限、5G低挂高、铁塔风荷载受限等问题,对A+P(Combination of active and passive antennas)一体化设备在中国电信和中国联通的5G基站建设中的使用方式提出一些建议,根据A+P设备在不同建设场景来进行工程建设、投资分析,说明A+P一体化设备的较高实用性。
