Ka频段卫星通信信道上多用户OFDM自适应资源分配方案
发布时间：2019-02-13 04:19
【摘要】：本文结合中国航天科技集团第五研究院504研究所的合作课题,在Ka频段卫星通信信道上研究了多用户OFDM自适应功率和比特分配技术。与传统的卫星通信相比,本文研究的Ka频段卫星通信具有可用带宽宽、通信容量大、抗干扰能力强、保密性好等特点。因此在军事通信和商用通信中都得到了广泛应用。但是,Ka频段移动卫星通信由于频段较高,因此该频段容易受到降雨衰减、大气吸收、闪烁和云雾衰减等天气因素的影响,加上卫星通信存在的多径效应和阴影效应,必须采用必要的措施来减少这些不利因素的影响。OFDM技术由于结构简单、频谱利用率高、抗频率选择性和信道时变性的特点,加上自适应技术可根据信道的变化改变调制方式,发送功率等参数,以最大限度地发送信息,提高通信系统的资源利用率和系统吞吐量。因此,自适应传输技术与OFDM技术的结合可以有效提高系统的传输性能。论文首先完成了搭建Ka频段移动卫星通信信道模型,模拟了在不同天气条件下Ka频段传输性能,并进行了计算机分析仿真。其次,建立了该信道下研究针对LDPC码和Kite码多用户OFDM系统的自适应资源分配,针对用户数据传输速率和目标误码率一定的条件下,使系统总发射功率最小化的原则选择了联合子载波、功率和比特自适应分配算法。进行性能的仿真,并得出在轻度阴影条件下适合采用kite码,在中度和重度阴影条件下适合采用ccsds标准的LDPC码的结论。最后提出在算法中加入了约束条件,并比较了有约束条件和没有约束条件的联合资源分配方案的性能。结论显示在保证了每个用户的传输速率的前提下,有约束条件的性能与没有约束条件的性能很接近,这样可以在不以牺牲个别用户服务质量的情况下保证信道的传输性能。论文虽然提出了一些结论,但是还存在需要改进的地方,下一步的研究可以延续这个方向深入工作。在本文中假定的发送端已知信道信息,这样就没有考虑信道估计,下一步可研究。另外在多用户资源分配中,本文提出加入约束条件,但是约束条件并没有进行深一层研究,这个方向可以作为下一步的研究课题。
[Abstract]:In this paper, the multi-user OFDM adaptive power and bit allocation techniques are studied on the Ka band satellite communication channel with the cooperation of 504 Institute of the Fifth Research Institute of China Aerospace Science and Technology Corporation. Compared with the traditional satellite communication, the Ka band satellite communication studied in this paper has the advantages of wide available bandwidth, large communication capacity, strong anti-jamming ability and good confidentiality. Therefore, it has been widely used in military communication and commercial communication. However, because of the high frequency band of mobile satellite communication in the Ka band, the frequency band is vulnerable to weather factors such as rainfall attenuation, atmospheric absorption, flicker and cloud attenuation, plus the multipath effect and shadow effect of satellite communication. It is necessary to adopt necessary measures to reduce the influence of these adverse factors. Due to the characteristics of simple structure, high spectral efficiency, anti-frequency selectivity and channel time-variability, OFDM technology can change the modulation mode according to the variation of the channel. Transmission power and other parameters to maximize the transmission of information, improve the communication system resource utilization and system throughput. Therefore, the combination of adaptive transmission technology and OFDM technology can effectively improve the transmission performance of the system. In this paper, the channel model of mobile satellite communication in Ka band is built firstly, and the transmission performance of Ka band under different weather conditions is simulated, and the computer analysis and simulation are carried out. Secondly, the adaptive resource allocation for LDPC code and Kite code multiuser OFDM system is studied in this channel, and the data transmission rate and the target bit error rate are fixed. In order to minimize the total transmit power of the system, the combined subcarrier, power and bit adaptive allocation algorithms are selected. The simulation results show that kite code is suitable for light shadow condition and ccsds standard LDPC code for medium and heavy shadow condition. Finally, a constraint condition is added to the algorithm, and the performance of the joint resource allocation scheme with and without constraints is compared. The conclusion shows that the performance of the channel with constraints is close to that of those without constraints on the premise of ensuring the transmission rate of each user, so that the transmission performance of the channel can be ensured without sacrificing the quality of service of individual users. Although some conclusions are put forward in this paper, there are still some problems to be improved, and the further research can continue in this direction. In this paper, the channel information is known to the sender, so channel estimation is not considered, so the next step can be studied. In addition, in the multi-user resource allocation, this paper proposes the addition of constraints, but the constraints have not been further studied, this direction can be used as the next research topic.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.2
[Abstract]:In this paper, the multi-user OFDM adaptive power and bit allocation techniques are studied on the Ka band satellite communication channel with the cooperation of 504 Institute of the Fifth Research Institute of China Aerospace Science and Technology Corporation. Compared with the traditional satellite communication, the Ka band satellite communication studied in this paper has the advantages of wide available bandwidth, large communication capacity, strong anti-jamming ability and good confidentiality. Therefore, it has been widely used in military communication and commercial communication. However, because of the high frequency band of mobile satellite communication in the Ka band, the frequency band is vulnerable to weather factors such as rainfall attenuation, atmospheric absorption, flicker and cloud attenuation, plus the multipath effect and shadow effect of satellite communication. It is necessary to adopt necessary measures to reduce the influence of these adverse factors. Due to the characteristics of simple structure, high spectral efficiency, anti-frequency selectivity and channel time-variability, OFDM technology can change the modulation mode according to the variation of the channel. Transmission power and other parameters to maximize the transmission of information, improve the communication system resource utilization and system throughput. Therefore, the combination of adaptive transmission technology and OFDM technology can effectively improve the transmission performance of the system. In this paper, the channel model of mobile satellite communication in Ka band is built firstly, and the transmission performance of Ka band under different weather conditions is simulated, and the computer analysis and simulation are carried out. Secondly, the adaptive resource allocation for LDPC code and Kite code multiuser OFDM system is studied in this channel, and the data transmission rate and the target bit error rate are fixed. In order to minimize the total transmit power of the system, the combined subcarrier, power and bit adaptive allocation algorithms are selected. The simulation results show that kite code is suitable for light shadow condition and ccsds standard LDPC code for medium and heavy shadow condition. Finally, a constraint condition is added to the algorithm, and the performance of the joint resource allocation scheme with and without constraints is compared. The conclusion shows that the performance of the channel with constraints is close to that of those without constraints on the premise of ensuring the transmission rate of each user, so that the transmission performance of the channel can be ensured without sacrificing the quality of service of individual users. Although some conclusions are put forward in this paper, there are still some problems to be improved, and the further research can continue in this direction. In this paper, the channel information is known to the sender, so channel estimation is not considered, so the next step can be studied. In addition, in the multi-user resource allocation, this paper proposes the addition of constraints, but the constraints have not been further studied, this direction can be used as the next research topic.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.2
【相似文献】
相关期刊论文 前10条
1 吴秋生,延波,薛良金;Ka频段脊波导过渡的仿真与工程应用[J];红外与毫米波学报;2002年02期
2 李方;鄢泽洪;张天龄;刘兵;;Ka频段双频圆极化器小型化设计[J];电子科技;2008年10期
3 张学e，
本文编号：2421171
本文链接：https://www.wllwen.com/kejilunwen/wltx/2421171.html
