文章针对移动通信系统、射频识别系统、超宽带通信系统对天线的性能要求,使用耳蜗螺旋仿生辐射结构作为阵元天线,谢尔宾斯基分形结构作为阵列排布结构,设计了一款分形阵列螺旋仿生超宽带天线,并对其工作性能进行了测试。测试结果表明,...文章针对移动通信系统、射频识别系统、超宽带通信系统对天线的性能要求,使用耳蜗螺旋仿生辐射结构作为阵元天线,谢尔宾斯基分形结构作为阵列排布结构,设计了一款分形阵列螺旋仿生超宽带天线,并对其工作性能进行了测试。测试结果表明,该款天线的工作频带范围为0.537~13.158 GHz,工作带宽为12.621 GHz,带宽倍频程为24.51,回波损耗最小值为-32.08 d B。该款天线完全覆盖了移动通信系统所有工作频段、射频识别系统频段、超宽带系统频段。因此,它是一款性能很好的超高兼容性通信天线。展开更多
In order to guarantee reliable data transmission, powerful channel coding techniques are usually required in noncoherent ultra-wideband(UWB) communication systems. Accordingly, several forward error correction(FEC) co...In order to guarantee reliable data transmission, powerful channel coding techniques are usually required in noncoherent ultra-wideband(UWB) communication systems. Accordingly, several forward error correction(FEC) codes, such as Reed-Solomon and convolutional codes have been used in noncoherent UWB systems to improve the bit error rate(BER) performance. In this paper, low-density parity-check(LDPC) codes are further studied as more powerful FEC candidates for noncoherent UWB systems. Two LDPC codes and the corresponding decoding procedures are presented for noncoherent UWB systems. Moreover, performance comparison between the LDPC codes and other FEC codes are provided for three major noncoherent UWB communication systems, namely, noncoherent pulse position modulation(NC-PPM), transmitted reference(TR) and transmitted reference pulse cluster(TRPC). Both theoretical analysis and simulation results show that the two investigated LDPC codes outperform other existing FEC codes with limited penalty in terms of complexity and therefore they are promising FEC candidates for noncoherent UWB systems with low-cost and low-power consumption.展开更多
In this paper,a novel UWB communication system structure is proposed.The transmitted signal uses OOK modulation and chirp spread spectrum.The received signal first goes through a dechirp pulse compression process,and ...In this paper,a novel UWB communication system structure is proposed.The transmitted signal uses OOK modulation and chirp spread spectrum.The received signal first goes through a dechirp pulse compression process,and then is processed with a two-level sliding correlation algorithm for coarse timing synchronization and fine timing synchronization.After the SNR estimation,the signal is demodulated by an energy detection method.An integrated system level simulation model is established,and the performance of this system is evaluated over the AWGN channel,IEEE 802.15.3a CM1 and CM4 channels.The theoretical analysis and simulation results show that this UWB communication system can effectively reduce the sampling rate and signal processing speed at the receiver,and it is more suitable for long-distance and low-rate UWB communications with high spreading gain.展开更多
文摘文章针对移动通信系统、射频识别系统、超宽带通信系统对天线的性能要求,使用耳蜗螺旋仿生辐射结构作为阵元天线,谢尔宾斯基分形结构作为阵列排布结构,设计了一款分形阵列螺旋仿生超宽带天线,并对其工作性能进行了测试。测试结果表明,该款天线的工作频带范围为0.537~13.158 GHz,工作带宽为12.621 GHz,带宽倍频程为24.51,回波损耗最小值为-32.08 d B。该款天线完全覆盖了移动通信系统所有工作频段、射频识别系统频段、超宽带系统频段。因此,它是一款性能很好的超高兼容性通信天线。
基金supported in part by the National Natural Science Foundation of China under Grant 61271262, 61473047 and 61572083Shaanxi Provincial Natural Science Foundation under Grant 2015JM6310the Special Fund for Basic Scientific Research of Central Colleges, Chang’an University under Grant 310824152010 and 00092014G1241043
文摘In order to guarantee reliable data transmission, powerful channel coding techniques are usually required in noncoherent ultra-wideband(UWB) communication systems. Accordingly, several forward error correction(FEC) codes, such as Reed-Solomon and convolutional codes have been used in noncoherent UWB systems to improve the bit error rate(BER) performance. In this paper, low-density parity-check(LDPC) codes are further studied as more powerful FEC candidates for noncoherent UWB systems. Two LDPC codes and the corresponding decoding procedures are presented for noncoherent UWB systems. Moreover, performance comparison between the LDPC codes and other FEC codes are provided for three major noncoherent UWB communication systems, namely, noncoherent pulse position modulation(NC-PPM), transmitted reference(TR) and transmitted reference pulse cluster(TRPC). Both theoretical analysis and simulation results show that the two investigated LDPC codes outperform other existing FEC codes with limited penalty in terms of complexity and therefore they are promising FEC candidates for noncoherent UWB systems with low-cost and low-power consumption.
基金Supported by the National High Technology Research and Development Program of China(No.2009 AA011202,2009AA011205)the National Science and Technology Major Project of China(No.2009ZX03006-007)
文摘In this paper,a novel UWB communication system structure is proposed.The transmitted signal uses OOK modulation and chirp spread spectrum.The received signal first goes through a dechirp pulse compression process,and then is processed with a two-level sliding correlation algorithm for coarse timing synchronization and fine timing synchronization.After the SNR estimation,the signal is demodulated by an energy detection method.An integrated system level simulation model is established,and the performance of this system is evaluated over the AWGN channel,IEEE 802.15.3a CM1 and CM4 channels.The theoretical analysis and simulation results show that this UWB communication system can effectively reduce the sampling rate and signal processing speed at the receiver,and it is more suitable for long-distance and low-rate UWB communications with high spreading gain.
