## 1 Introduction  
Wireless power transfer (WPT) is a promising technology that transfers electrical energy from a power source to an electronic load. By eliminating the necessity of physical connectors or wires between the source and the load, WPT systems provide a user-friendly experience and effective charging performance. Therefore, WPT has garnered considerable interest among researchers over an extended period, with current technological breakthroughs further amplifying its significance, especially for electrical vehicles [1; 2; 3]. WPT users can charge their electric vehicles (EVs) without the hassle of plugging and unplugging cords, which improves their user experience and enables the complete process of automated parking and charging without human intervention. WPT systems have the potential to be designed to meet the requirements of the charging curve of on-board batteries [4], which normally includes a constant current (CC) phase, followed by a constant voltage (CV) phase, and finally a cutoff phase [5]. Using LCC-LCC compensation, WPT systems can maintain a constant charging current that is basically non-variable as the battery voltage rises during CC charging, which is inherent to the system characteristics of LCC-LCC-compensated systems and matches the CCphase perfectly. Once the battery approaches a given voltage level, a constant voltage (CV phase) needs to be maintained, and the charging current has to be gradually decreased to prevent overcharging. Therefore, in the CV and cutoff phases, WPT systems should be capable of adjusting the secondary DC current (the battery charging current) with a constant secondary DC voltage (the constant battery voltage in the CV and cutoff phases). To achieve these charging curve requirements, WPT systems should typically include wireless information transfer (WIT) to continuously send back the battery status (e.g., the charging phase, voltage, and required power) and adjust the control parameters of the power electronics on both sides (i.e., the inverter and active rectifier) in real time. WPT systems in EV charging applications have specific requirements for the associated communication to ensure safe, efficient, and controllable charging processes. The specific requirements encompass two main aspects:  
* **Real time**: The communication should offer real-time capabilities for swift responses and effective control of the system parameters and charging process. This is crucial for monitoring the battery status [6, 7], adjusting power, detecting foreign objects [8, 9, 10] and faults [11], and ensuring system stability during the charging process. * **Point-to-point**: Especially in scenarios with multiple ground assemblies (GAs) or multiple vehicle assemblies (VAs), the point-to-point nature of near-field communication can be utilized to ensure a reliable pairing mechanism. This avoids mismatches between a GA and a VA and the resulting danger, such as the unloaded and exposed GA operation. Standard far-field communication technologies typically have higher latency than near-field communication. Wi-Fi latency generally ranges from several milliseconds to 30 ms, while 4G LTE networks provide round-trip latency ranging from 30 to 50 ms, and 5G's latency can be as low as 1 ms or even lower in ideal conditions. However, 5G requires significantly higher computational power, while near field communication (NFC) can have extremely low latency under 1 ms with low hardware costs. Furthermore, the point-to-point feature of NFC helps the pairing process between a GA and a VA, which is difficult with far-field communication technologies. Due to the two points mentioned above, many previous studies have investigated the near-field-based communication methods for WPT. A review of the previous works related to the communication for WPT systems is presented in Table 1. In [12, 13, 14], the communication signal was modulated using power electronics that reduced the system complexity because no extra digital-to-analog converter (DAC) was needed for signal modulation.