Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output ...Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output (SISO) systems. To solve these problems, an integrated radar and communication system (IRCS) with multiple input multiple output (MIMO) OFDM waveform is proposed. The different limitations of radar and communication in designing such a system are investigated. Then, an optimization problem is devised to obtain suitable system parameters, including the number of subcarriers, subcarrier spacing, number of symbols, pulse repetition frequency (PRF) and length of cyclic prefix (CP). Finally, to satisfy the requirements of both radar and communication, the IRCS parameters are derived in three typical cases. Several numerical results are presented to illustrate the demands of radar and communication, inconsistent or consistent, for the IRCS parameters and the superiority of the proposed system.展开更多
Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inhe...Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. .展开更多
基于压缩感知(Compressed Sensing,CS)的OFDM(Orthogonal Frequency Division Multiplexing)系统稀疏信道估计有更小的导频开销和更好的信道估计效果。针对OFDM系统稀疏信道估计的导频图案设计,提出了一种基于双准则双分支的随机搜索算...基于压缩感知(Compressed Sensing,CS)的OFDM(Orthogonal Frequency Division Multiplexing)系统稀疏信道估计有更小的导频开销和更好的信道估计效果。针对OFDM系统稀疏信道估计的导频图案设计,提出了一种基于双准则双分支的随机搜索算法(Double Criteria and Double Branches Random Search Schemes,DCDB-RSS)。该算法结合互不相关(Mutual Incoherence Property,MIP)准则和格拉姆矩阵准则,在不同分支上采用不同优化准则全面地搜索最优导频图案,不仅解决了单一准则难以稳定取得最优导频图案的问题,同时也避免了陷入局部最优解。仿真结果表明,与现有导频优化算法相比,DCDB-RSS算法在相同时间复杂度的前提下,可以获得更小的误码率和提高约1dB的信道估计均方误差。展开更多
基金supported by the National Natural Science Foundation of China(6123101761671352)
文摘Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output (SISO) systems. To solve these problems, an integrated radar and communication system (IRCS) with multiple input multiple output (MIMO) OFDM waveform is proposed. The different limitations of radar and communication in designing such a system are investigated. Then, an optimization problem is devised to obtain suitable system parameters, including the number of subcarriers, subcarrier spacing, number of symbols, pulse repetition frequency (PRF) and length of cyclic prefix (CP). Finally, to satisfy the requirements of both radar and communication, the IRCS parameters are derived in three typical cases. Several numerical results are presented to illustrate the demands of radar and communication, inconsistent or consistent, for the IRCS parameters and the superiority of the proposed system.
文摘Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. .
文摘基于压缩感知(Compressed Sensing,CS)的OFDM(Orthogonal Frequency Division Multiplexing)系统稀疏信道估计有更小的导频开销和更好的信道估计效果。针对OFDM系统稀疏信道估计的导频图案设计,提出了一种基于双准则双分支的随机搜索算法(Double Criteria and Double Branches Random Search Schemes,DCDB-RSS)。该算法结合互不相关(Mutual Incoherence Property,MIP)准则和格拉姆矩阵准则,在不同分支上采用不同优化准则全面地搜索最优导频图案,不仅解决了单一准则难以稳定取得最优导频图案的问题,同时也避免了陷入局部最优解。仿真结果表明,与现有导频优化算法相比,DCDB-RSS算法在相同时间复杂度的前提下,可以获得更小的误码率和提高约1dB的信道估计均方误差。
