# Research on Waveform Adaptability Based on Lunar Channels
## 1 Introduction
OFDMA systems are highly flexible, allowing adjustments based on the requirements of the communication environment, accommodating different bandwidths, spectrum resource allocations, and the needs of multi-user, multi-antenna systems. Given its outstanding spectrum efficiency and its ability to resist multipath interference in complex environments, OFDMA is considered a promising choice for achieving stable communication on the lunar surface [10]. Meanwhile, Single Carrier Frequency Division Multiple Access (SC-FDMA) technology has proven to be effective in the field of communication [11]. It not only provides high data rates, but also has the advantage of low Peak-to-Average Power Ratio (PAPR), which helps reduce nonlinear distortion in power amplifiers [12]. SC-FDMA demonstrates good energy efficiency, contributing to the improvement of battery life and the reduction of power consumption [13]. This is crucial for the design of lunar exploration devices and lunar landers, as it can significantly enhance the operational time of exploration equipment. The organic integration of OFDMA and SC-FDMA technologies provides a comprehensive solution for the challenges in lunar communication. In this paper, we conducted an in-depth study of the application of OFDMA and SC-FDMA technologies in the lunar communication environment. By constructing realistic simulated terrain, we comprehensively considered various lunar environmental factors, including terrain elevation, obstacles, and restrictions on the movement of exploration devices. Simultaneously, we thoroughly accounted for the signal propagation characteristics in the lunar environment, employing a multipath fading model with frequency-selective fading characteristics to simulate the communication link between lunar exploration devices and lunar landers. Through experimental simulations, we validated that the proposed hybrid system can offer efficient and reliable communication transmission performance while maintaining PAPR performance. The primary objective of this thesis is to address the unique challenges posed by the lunar environment to communication systems and to ensure the reliability and stability of communication systems in lunar surface communications. We investigated the applicability of Orthogonal Frequency Division Multiple Access (OFDMA) and Single-Carrier Frequency Division Multiple Access (SC-FDMA) waveforms in the lunar environment and designed communication transmission waveforms tailored to this environment. Using Peak-to-Average Power Ratio (PAPR) and Bit Error Rate (BER) as performance indicators, we comprehensively explored different modulation schemes and cyclic prefix lengths to design communication transmission waveforms suitable for the lunar environment. The main contributions of our thesis include: proposing a new lunar surface channel model based on the unique lunar environment; providing an analysis of the applicability of OFDMA and SC-FDMA waveforms in lunar surface communication environments, which has important guiding significance for the design and optimization of communication systems in future lunar missions; verifying through simulation experiments that our designed hybrid system can provide efficient and reliable communication transmission performance while maintaining PAPR performance; and selecting the 4 QAM modulation scheme and demonstrating its superior performance in lunar surface communication environments through simulation results, contributing to the reliability and efficiency of communication systems under extreme lunar conditions. Section 2 delves into the lunar communication environment in detail, including an analysis of the H-ITM lunar radio wave propagation fading model and the calculation of path loss. Section 3 analyzes lunar surface communication requirements, covering various areas of lunar activities and their impact on the design of communication systems.