稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average...稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average Power Ratio,PAPR)特性。针对复用OFDM子载波SCMA系统具有高PAPR的特点,提出了一种低峰均比的SCMA多址方案,采用SC-FDMA技术,并进一步利用峰均比抑制技术对PAPR进行降低。理论和仿真结果表明,该算法能在PAPR性能、BER性能和系统复杂度间获得较好的权衡。展开更多
In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, th...In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, the algorithm minimizes the total transmit power while satisfying the total power and users' rate constraints. The result of simulation shows that the proposed algorithm reduces the average bit Signal-to-Noise Ratio (SNR) by approximately 4 dB compared with OFDM-Frequency Division Multiple Access (OFDM-FDMA), and supports more users in a multiuser Rayleigh fading channel. As assigning subcarriers in block, the computational complexity of the algorithm is much lower than that of the derivation of "water-filling" algorithm.展开更多
LTE A上行每帧数据在自适应传输时,不能实时切换为分簇的DFT S OFDM和N×SC FDMA系统。为此,提出一种联合自适应调制编码方法。该方法依据接收端的信干噪比,分别预测下一帧在采用分簇的DFT S OFDM和N×SC FDMA进行自适应传输时...LTE A上行每帧数据在自适应传输时,不能实时切换为分簇的DFT S OFDM和N×SC FDMA系统。为此,提出一种联合自适应调制编码方法。该方法依据接收端的信干噪比,分别预测下一帧在采用分簇的DFT S OFDM和N×SC FDMA进行自适应传输时的吞吐量,选择吞吐量大的系统及相应的调制编码方式在下一帧使用,可获得分簇的DFT S OFDM和N×SC FDMA系统在自适应传输时频谱效率的联合性能。仿真结果表明,与单一自适应系统相比,该方法在多径信道下的吞吐量性能能够取得1 dB增益。展开更多
文摘稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为一种新型非正交多址接入技术,具备一定的过载能力,满足5G无线通信网络海量连接等需求。SCMA系统通常将用户码字映射到OFDM子载波上,具有与OFDM信号相似的高峰均比(Peak to Average Power Ratio,PAPR)特性。针对复用OFDM子载波SCMA系统具有高PAPR的特点,提出了一种低峰均比的SCMA多址方案,采用SC-FDMA技术,并进一步利用峰均比抑制技术对PAPR进行降低。理论和仿真结果表明,该算法能在PAPR性能、BER性能和系统复杂度间获得较好的权衡。
基金Supported by the National 863 High-Tech Program of China (No.2001AA121031)the National Natural Science Foundation of China (GG065760242003)
文摘In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, the algorithm minimizes the total transmit power while satisfying the total power and users' rate constraints. The result of simulation shows that the proposed algorithm reduces the average bit Signal-to-Noise Ratio (SNR) by approximately 4 dB compared with OFDM-Frequency Division Multiple Access (OFDM-FDMA), and supports more users in a multiuser Rayleigh fading channel. As assigning subcarriers in block, the computational complexity of the algorithm is much lower than that of the derivation of "water-filling" algorithm.
文摘LTE A上行每帧数据在自适应传输时,不能实时切换为分簇的DFT S OFDM和N×SC FDMA系统。为此,提出一种联合自适应调制编码方法。该方法依据接收端的信干噪比,分别预测下一帧在采用分簇的DFT S OFDM和N×SC FDMA进行自适应传输时的吞吐量,选择吞吐量大的系统及相应的调制编码方式在下一帧使用,可获得分簇的DFT S OFDM和N×SC FDMA系统在自适应传输时频谱效率的联合性能。仿真结果表明,与单一自适应系统相比,该方法在多径信道下的吞吐量性能能够取得1 dB增益。
