| 摘要: |
| 分层调制技术是多媒体广播多播服务（MBMS）系统中一项重要关键技术。普通分层调制因为基本层和增强层之间的相互干扰，导致分层调制的误码率上升。提出了一种改进型分层调制，将基本层数据和增强层数据的星座图旋转，并且将调制信号的同相部分与正交部分进行交织。在不改变发送装置的条件下，通过搜索旋转最佳角度，获得信号空间增益。仿真结果表明，星座图旋转后的增强层信号的性能优于传统的增强层信号，采用近似方法求解旋转角度最优值是便捷有效的,并且在0°~45°的角度范围内，改变基本层和增强层的旋转角度可以获得的不同的误符率，为进一步推导出旋转角度的最优值提供了依据。 |
| 关键词: 多媒体广播多播服务（MBMS） 分层调制 星座旋转 矩阵旋转 交织技术 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（61363047）;佛山市科技创新项目（2016AG100382） |
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| An improved hierarchical modulation scheme for MBMS systems |
| ZHANG Yongtang,HUANG Zhongyou |
| () |
| Abstract: |
| Hierarchical modulation is an important key technology in multimedia broadcast multicast service(MBMS) system. Generic layered modulation interference between the base layer and the enhancement layer,results in the increase of hierarchical modulation error rate. This paper proposes an improved hierarchical modulation. Firstly,the constellation of data in basic layer and enhancement layer is rotated,and then the phase modulation signals and their orthogonal part are woven. Finally,the signal space gain is obtained by optimal rotation angle searching with the same transmitting device. Simulated experimental results show that the constellation signal of the enhancement layer after rotation is superior to that of traditional enhancement layer. It is simple and effective to solve the optimal rotation angle with the use of approximate method. In addition,different character error rates can be got by changing the rotation angle between the basic and enhancement layer within 0o~45o,which provides a basis support for further obtaining the optimal rotation angle. |
| Key words: multimedia broadcast multicast service(MBMS) hierarchical modulation constellation rotation matrix rotation interleaving technique |
《电讯技术》编辑部 