Chen Jing, Wang Baobing, Guo Jianzhong, Shan Xin, Kong Dejin
Electronic Information School, Wuhan University, Wuhan 430072, China.
School of Electronic and Electrical Engineering, Wuhan Textile University, Wuhan 430200, China.
Sensors (Basel). 2022 Aug 2;22(15):5772. doi: 10.3390/s22155772.
In classical orthogonal frequency division multiplexing (OFDM) systems, inserting the cyclic prefix (CP) is necessary before each symbol to overcome the multi-path effect, which, however, occupies numerous time-frequency radio resources, resulting in hampered spectrum efficiency. To address this issue, in this paper, symbol repetition aware OFDM (SR-OFDM) is developed to lower the overhead of CP. In the proposed SR-OFDM, multiple symbols share the same CP with which we examine that the multi-path channels can also be overcome by a simple single-tap equalization without causing any interference. Moreover, after the discrete Fourier transform at the receiver, different symbols are proved to be separated in the time domain, which is beneficial for lowering the demodulation complexity. Furthermore, it is revealed that the above conclusions still hold even under timing synchronization errors, which makes the proposed SR-OFDM favorable in real systems. Extensive simulations validate the efficacy of our proposed SR-OFDM system under the multi-path channels with or without timing synchronization errors.
在传统的正交频分复用（OFDM）系统中，为了克服多径效应，在每个符号之前插入循环前缀（CP）是必要的，然而，这占用了大量的时频无线资源，导致频谱效率受到阻碍。为了解决这个问题，本文提出了符号重复感知OFDM（SR-OFDM）以降低CP的开销。在所提出的SR-OFDM中，多个符号共享相同的CP，通过简单的单抽头均衡，我们验证了多径信道也可以被克服，且不会产生任何干扰。此外，在接收机进行离散傅里叶变换后，不同的符号在时域中被证明是可分离的，这有利于降低解调复杂度。此外，研究表明即使在定时同步误差的情况下上述结论仍然成立，这使得所提出的SR-OFDM在实际系统中具有优势。大量仿真验证了我们所提出的SR-OFDM系统在有无定时同步误差的多径信道下的有效性。
