In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determin...In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determined by the average delay profile and the Doppler spectra. The profile characteristics and their influences on channel behavior are also examined.展开更多
In the new era of railways, infrastructure, trains and travelers will be interconnected. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required. This motivates t...In the new era of railways, infrastructure, trains and travelers will be interconnected. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required. This motivates the exploration of the underutilized millimeter wave （mmWave） as well as the largely unexplored THz band. In this paper, we first identify relevant communication scenarios for railway applications. Then the specific challenges and estimates of the bandwidth requirements for high-data rate railway connec-tivity in these communication scenarios are described. Finally, we outline the major challenges on propagation channel modeling and provide a technical route for further studies.展开更多
This paper presents a software simulator applicable to multipath fading channels in urban environments of mobile communication networks. The simulator is constructed by a two-state Markov model and several statistical...This paper presents a software simulator applicable to multipath fading channels in urban environments of mobile communication networks. The simulator is constructed by a two-state Markov model and several statistical models for simulating the characterizations of different environments. A core idea of the simulator is to construct a Rice distribution-based multipath fading module produced by a modified Gans Doppler power spectrum, and in combination with a Markov model to predict the time-dependent characteristics of packet in different radio circumstances. It can simply predict the packet performance of the future channel and evaluate the relations between the radio channel and the modulation schemes, error control protocols and channel coding. Simulation results demonstrate that it is a reliable and efficient method.展开更多
The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if...The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if not in a complicated topography.Testing results show that it is hardly to characterize the radio propagation properties for the antenna installed on the ground.In order to ensure a successful communication,the radio frequency(RF)wireless signal intensity monitor system was designed.We can get the wireless link transmission loss through measuring signal strength from received node.The test shows that the near-ground wireless signal propagation characteristics still can be characterized by the log distance propagation loss model.These results will conduce to studying the transmission characteristic of Near-Earth wireless signals and will predict the coverage of the earth's surface wireless sensor network.展开更多
TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A nov...TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A novel downlink multiuser transmission scheme Joint Transmission (JT) is proposed based on the reciprocity that in the case of TDD the same channel impulse responses are valid for both the uplink and the downlink, it can enhance system performance and reduce system complexity. Because no channel estimation is necessary at the MSs, the data detection effort is dramatically reduced. This paper apply JT in Time Division CDMA (TD-SCDMA) and analyze its proformance in contrast to state of the art TD-CDMA transceivers. The computer simulation results illustrate the superiority of the novel scheme in terms of the system performance in the downlink of TD-SCDMA.展开更多
The guided scrambling code, a new line code, is deeply studied in this paper. The theory ts provedthat the output characteristics of guided scrambling code is similar to that of 'Mite Notse' in some condi-tio...The guided scrambling code, a new line code, is deeply studied in this paper. The theory ts provedthat the output characteristics of guided scrambling code is similar to that of 'Mite Notse' in some condi-tions. The results of the theory analysis accord with that of fhe experunent. So, the system with the guidedscrambling code would have good performance.展开更多
The multipath fading channel,models are described in this paper in order to investigate their per-formance for digrtal radio transmissions. The simulation model for such fading channels are focused on thepoints as fol...The multipath fading channel,models are described in this paper in order to investigate their per-formance for digrtal radio transmissions. The simulation model for such fading channels are focused on thepoints as follows: 1) Optimal signal desigu; 2) High-performance receiver design; 3) Communication systemperformance analysis; 4) Reliable high-performance equalizing schemes. Finally, the simulation program of64 QAM digital radio with an adaptive equalizer is desigued and the simulation results are presented to showsome conclusrons we have reached.展开更多
文摘In this paper, the bit error rate (BER) performance for typical mobile radio channels is simulated and analyzed based on a tapped delay line model. The investigation is focused on the propagation environments determined by the average delay profile and the Doppler spectra. The profile characteristics and their influences on channel behavior are also examined.
文摘In the new era of railways, infrastructure, trains and travelers will be interconnected. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required. This motivates the exploration of the underutilized millimeter wave （mmWave） as well as the largely unexplored THz band. In this paper, we first identify relevant communication scenarios for railway applications. Then the specific challenges and estimates of the bandwidth requirements for high-data rate railway connec-tivity in these communication scenarios are described. Finally, we outline the major challenges on propagation channel modeling and provide a technical route for further studies.
基金Supported by the National Natural Science Foundation of China (40474055)
文摘This paper presents a software simulator applicable to multipath fading channels in urban environments of mobile communication networks. The simulator is constructed by a two-state Markov model and several statistical models for simulating the characterizations of different environments. A core idea of the simulator is to construct a Rice distribution-based multipath fading module produced by a modified Gans Doppler power spectrum, and in combination with a Markov model to predict the time-dependent characteristics of packet in different radio circumstances. It can simply predict the packet performance of the future channel and evaluate the relations between the radio channel and the modulation schemes, error control protocols and channel coding. Simulation results demonstrate that it is a reliable and efficient method.
文摘The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if not in a complicated topography.Testing results show that it is hardly to characterize the radio propagation properties for the antenna installed on the ground.In order to ensure a successful communication,the radio frequency(RF)wireless signal intensity monitor system was designed.We can get the wireless link transmission loss through measuring signal strength from received node.The test shows that the near-ground wireless signal propagation characteristics still can be characterized by the log distance propagation loss model.These results will conduce to studying the transmission characteristic of Near-Earth wireless signals and will predict the coverage of the earth's surface wireless sensor network.
文摘TD-SCDMA has been decided as the standard for TDD mode of the 3rd Generation mobile radio system by International Telecommunications Union (ITU),it is a important breakthrough in a century communication history. A novel downlink multiuser transmission scheme Joint Transmission (JT) is proposed based on the reciprocity that in the case of TDD the same channel impulse responses are valid for both the uplink and the downlink, it can enhance system performance and reduce system complexity. Because no channel estimation is necessary at the MSs, the data detection effort is dramatically reduced. This paper apply JT in Time Division CDMA (TD-SCDMA) and analyze its proformance in contrast to state of the art TD-CDMA transceivers. The computer simulation results illustrate the superiority of the novel scheme in terms of the system performance in the downlink of TD-SCDMA.
文摘The guided scrambling code, a new line code, is deeply studied in this paper. The theory ts provedthat the output characteristics of guided scrambling code is similar to that of 'Mite Notse' in some condi-tions. The results of the theory analysis accord with that of fhe experunent. So, the system with the guidedscrambling code would have good performance.
文摘The multipath fading channel,models are described in this paper in order to investigate their per-formance for digrtal radio transmissions. The simulation model for such fading channels are focused on thepoints as follows: 1) Optimal signal desigu; 2) High-performance receiver design; 3) Communication systemperformance analysis; 4) Reliable high-performance equalizing schemes. Finally, the simulation program of64 QAM digital radio with an adaptive equalizer is desigued and the simulation results are presented to showsome conclusrons we have reached.
