| 题名 | 一种新的OFDM-CPM系统实现与研究 |
| 作者 | 杨雪梅 |
| 学位类别 | 博士 |
| 答辩日期 | 2007-06-02 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 声学研究所 |
| 关键词 | 正交频分复用 连续相位调制 峰值平均功率比 自适应调制 空时编码 |
| 其他题名 | Realization and Study of A Novel OFDM-CPM System |
| 学位专业 | 信号与信息处理 |
| 中文摘要 | 正交频分复用（OFDM）技术是未来无线通信的关键技术。连续相位调制（CPM）是一种恒包络记忆调制，内在的相位记忆特性使CPM调制具有一定的错误纠正能力。 本文把CPM调制引入OFDM系统，构建一个新的OFDM-CPM映射调制方案。利用CPM的记忆特性在OFDM系统中引入相关，从而可以进行多符号检测。理论推导和仿真结果都表明OFDM-CPM系统比传统的OFDM具有更好的误码性能。OFDM-CPM同样存在对峰值平均功率比（PAPR）敏感的问题。因为CPM的恒包络调制，在不做任何PAPR相关处理的情况下，相对于QAM也具有更低的PAPR。文中分析了线性分组编码和部分传输序列（PTS）方法对OFDM-CPM的影响。 提出了OFDM-CPM多符号检测的最佳接收机模型，并推导出误码率的联合边界，同时提出简单实用的频域接收机。在AWGN和瑞利衰落不同信道环境下进行仿真，和传统OFDM系统进行性能比较，OFDM-CPM系统的误码性能优于OFDM-PSK。 本文提出了利用CPM调制构建新的自适应OFDM-CPM调制系统。同时提出两种基于子带划分的比特功率分配方法。固定速率传输的情况，提出适合OFDM-CPM的比特分配算法，可变速率传输的情况下，使用固定阈值门限法进行自适应调制。 研究了把OFDM-CPM 信号和空时分组编码（STBC）相结合的扩展应用，空时编码可以在频率选择性信道中提供有效的分集增益，同时由于CPM在系统中引入相关，使STBC OFDM-CPM比传统的STBC OFDM具有更好的误码性能。 |
| 英文摘要 | Orthogonal Frequency Division Multiplexing (OFDM) is a key technic in the wireless applications in future. Continuous phase modulation (CPM) has been an attractive memory modulation scheme for constant envelope and the better BER performance and desired spectrum can be got for the phase memory character.. A new scheme is introduced combining CPM modulation and OFDM system. Using the correlated phase state in the mapping processing we could realize the novel multi-symbol detection instead of symbol by symbol detection in the receiver. The theory analysis and the simulation results show that the new OFDM-CPM system has the better BER performance than traditional OFDM system. The OFDM-CPM system is also sensitive to the Peak-to-Average Radio (PAPR). The OFDM-CPM system has the better PAPR character than the OFDM without any other PAPR reduction because the CPM signal is envelope. The results are given to reduce PAPR with linear block coding and Partial Transmit Sequences (PTS) in A new multi-symbol receiver for optimum detection and the corresponding united BER bound have been derived. So the simple post FFT receiver is proposed. The comparison is simulated in AWGN and multipath fading channel and OFDM-CPM performs better than conventional OFDM-PSK. A new OFDM-CPM adaptive modulation system is proposed. Two new methods of bit allocation are proposed based on subbands in OFDM-CPM system. One is for for constant transmitting and the other based on fixed threshold for variable bit rate data transmitting. The performance of adaptive OFDM-CPM system is examined by simulation. The application is analyzed combing OFDM-CPM and space-time block code (STBC). Space-time codes could provide effective diversity gain in frequency selective channel and the better BER performance could be got with CPM in STBC OFDM-CPM system. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 124 |
| 内容类型 | 学位论文 |
| 源URL | [http://159.226.59.140/handle/311008/182]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 杨雪梅. 一种新的OFDM-CPM系统实现与研究[D]. 声学研究所. 中国科学院声学研究所. 2007. |
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