正交频分复用的一种拓展技术

提出了正交频分复用的一种拓展技术——重叠频分复用（OVFDM）技术，即相对于正交频分复用在频率域载波间正交的特性，OVFDM在频率域考虑更一般的载波间隔，使载波彼此重叠在一起，形成约束关系. 这种技术不但可以提高频谱效率，还可以获得编码增益；如果在接收端使用加窗后的极大似然序列检测（MLSD），则可以限制复杂度. 由于在OVFDM系统中，不是依靠正交性来避免干扰，而是依靠符号间相互的约束关系来提高抗干扰能力，所以OVFDM可以更加灵活地提高系统频谱效率，不再使用循环前缀. 理论分析及仿真结果验证了这种技术的正确性.

An Extension Technique from OFDM

An extension technique from orthogonal frequency division multiplexing（OFDM） named overlapped frequency division multiplexing (OVFDM) is presented. Compared to the orthogonality between the carriers in OFDM system, OVFDM focus on the general frequency spacing of subcarriers. The method proposed not only improves the spectral efficiency of OFDM system but generates the coding constraint relationship. The detection algotirhm in the receiver is actually a frequency domain maximum likelihood sequence detection (MLSD) after using window function, and the complexity is limited moreover. Because OVFDM is not depend on the orthogonality among subcarriers but on the convolution constraint relationship among them, its spectral efficiency could be improved optionally. And the system’s spectrum and power are more effective because there exists no cyclic prefix. Analysis and simulation verify the validity of this theory.