Ka頻段衛(wèi)星通信信道上多用戶OFDM自適應(yīng)資源分配方案
發(fā)布時(shí)間：2019-02-13 04:19
【摘要】：本文結(jié)合中國航天科技集團(tuán)第五研究院504研究所的合作課題,在Ka頻段衛(wèi)星通信信道上研究了多用戶OFDM自適應(yīng)功率和比特分配技術(shù)。與傳統(tǒng)的衛(wèi)星通信相比,本文研究的Ka頻段衛(wèi)星通信具有可用帶寬寬、通信容量大、抗干擾能力強(qiáng)、保密性好等特點(diǎn)。因此在軍事通信和商用通信中都得到了廣泛應(yīng)用。但是,Ka頻段移動衛(wèi)星通信由于頻段較高,因此該頻段容易受到降雨衰減、大氣吸收、閃爍和云霧衰減等天氣因素的影響,加上衛(wèi)星通信存在的多徑效應(yīng)和陰影效應(yīng),必須采用必要的措施來減少這些不利因素的影響。OFDM技術(shù)由于結(jié)構(gòu)簡單、頻譜利用率高、抗頻率選擇性和信道時(shí)變性的特點(diǎn),加上自適應(yīng)技術(shù)可根據(jù)信道的變化改變調(diào)制方式,發(fā)送功率等參數(shù),以最大限度地發(fā)送信息,提高通信系統(tǒng)的資源利用率和系統(tǒng)吞吐量。因此,自適應(yīng)傳輸技術(shù)與OFDM技術(shù)的結(jié)合可以有效提高系統(tǒng)的傳輸性能。論文首先完成了搭建Ka頻段移動衛(wèi)星通信信道模型,模擬了在不同天氣條件下Ka頻段傳輸性能,并進(jìn)行了計(jì)算機(jī)分析仿真。其次,建立了該信道下研究針對LDPC碼和Kite碼多用戶OFDM系統(tǒng)的自適應(yīng)資源分配,針對用戶數(shù)據(jù)傳輸速率和目標(biāo)誤碼率一定的條件下,使系統(tǒng)總發(fā)射功率最小化的原則選擇了聯(lián)合子載波、功率和比特自適應(yīng)分配算法。進(jìn)行性能的仿真,并得出在輕度陰影條件下適合采用kite碼,在中度和重度陰影條件下適合采用ccsds標(biāo)準(zhǔn)的LDPC碼的結(jié)論。最后提出在算法中加入了約束條件,并比較了有約束條件和沒有約束條件的聯(lián)合資源分配方案的性能。結(jié)論顯示在保證了每個(gè)用戶的傳輸速率的前提下,有約束條件的性能與沒有約束條件的性能很接近,這樣可以在不以犧牲個(gè)別用戶服務(wù)質(zhì)量的情況下保證信道的傳輸性能。論文雖然提出了一些結(jié)論,但是還存在需要改進(jìn)的地方,下一步的研究可以延續(xù)這個(gè)方向深入工作。在本文中假定的發(fā)送端已知信道信息,這樣就沒有考慮信道估計(jì),下一步可研究。另外在多用戶資源分配中,本文提出加入約束條件,但是約束條件并沒有進(jìn)行深一層研究,這個(gè)方向可以作為下一步的研究課題。
[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.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：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.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN927.2
【相似文獻(xiàn)】
相關(guān)期刊論文 前10條
1 吳秋生,延波,薛良金;Ka頻段脊波導(dǎo)過渡的仿真與工程應(yīng)用[J];紅外與毫米波學(xué)報(bào);2002年02期
2 李方;鄢澤洪;張?zhí)忑g;劉兵;;Ka頻段雙頻圓極化器小型化設(shè)計(jì)[J];電子科技;2008年10期
3 張學(xué)e，
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