In this paper, new pilot insertion techniques that make use of index modulation (IM) idea for channel estimation (CE) are proposed for orthogonal frequency division multiplexing (OFDM) systems. These techniques not only perform CE but also convey additional bits. Simulation results show that the performance of the proposed schemes are very close to the performance of the classical pilot symbol-assisted (PSA) OFDM system, with the additional benefit that more bits can be transmitted. Despite a slight increase in the complexity of the receiver, higher spectral efficiency than conventional OFDM systems can be achieved. Especially, the proposed method-II transmits more bits than the proposed method-I owing to its subblock form.

在本文中，针对正交频分复用（OFDM）系统提出了利用索引调制（IM）思想进行信道估计（CE）的新导频插入技术。这些技术不仅执行CE，而且还传达其他位。仿真结果表明，所提出方案的性能非常接近经典导频符号辅助（PSA）OFDM系统的性能，并具有可以传输更多比特的额外好处。尽管接收机的复杂度略有增加，但仍可实现比传统OFDM系统更高的频谱效率。特别地，由于其子块形式，所提出的方法-II比所提出的方法-I传输更多的比特。