# Regularized Zero-Forcing Dirty Paper Precoding in a High-Throughput Satellite Communication System
## 1 Introduction  
With the development of the global mobile Internet and the \"ubiquitous\" network demand of individual consumers, a high-throughput satellite communication system with the characteristics of \"operating in high frequency band, high throughput and providing broadband Internet access service\" is the development trend [1]. With the same spectrum resources, high-throughput satellites can obtain several times the communication capacity than that of fixed satellites by using multi-beam and frequency reuse technology. On the premise of maximizing the available data rate and spectrum utilization efficiency, high-throughput satellites have adopted the full spectrum reuse scheme, which will cause serious co-frequency interference. Precoding technology is an effective method to deal with this problem. The principle of precoding technology is to complete signal processing according to channel state information, so as to mitigate interference and improve link performance. Precoding technology is generally applied to the downlink channel of the forward link of high-throughput satellites. Precoding technology is mainly divided into linear and nonlinear precoding technology. Although traditional nonlinear precoding can achieve better performance, it is difficult to apply in practice due to its high complexity, such as the use of dirty paper coding which, can achieve the optimal capacity [2]. However, linear precoding has received extensive attention in the academic community due to its relatively low complexity. The classical zero-forcing precoding algorithm [3] in linear precoding was first applied to high-throughput satellites by [PERSON] and [PERSON] [4]. It has been proven that linear precoding technology can effectively improve the communication capacity performance of the system. At the same time, the influence of channel estimation error, feedback delay, and on-board payload on the overall system performance is also studied and analyzed. Subsequently, reference [5] focuses on the performance of spectrum utilization when aKa-band high-throughput satellite system adopts regularized zero-forcing linear precoding, and studies the terrestrial user grouping service under the practical constraints of channel state information delay and oscillator phase noise. On this basis, reference [6] reasonably applies nonlinear dirty paper coding technology in a high-throughput satellite system based on the DVB-S2 standard, and compares it with linear methods such as zero-forcing and regularized zero-forcing. They provide the performance upper limit of the multi-beam joint precoding method, and verify the relationship between beam coverage parameters and system communication capacity. Reference [7] proposes a real-time demonstration of precoding technology, which is used to realize full spectrum reuse in the forward link of a future high-throughput satellite system, proving the feasibility of precoding in satellite communications based on the superframe structure defined in DVB-S2X standard. Reference [8] designs a zero-forcing precoder using partial channel state information for matrix and vector normalization, which can reduce the delay and signaling overhead by reducing the channel state information feedback from the user terminal. Reference [9] summarizes the latest precoding technology for a high-throughput satellite system, and points out its future development direction and challenges. Reference [10] surveys the alternative fade mitigation techniques for satellite communication systems operating at Ku, Ka, and V frequency bands. The specific phenomena influencing the propagation of radio waves on Earth-space links are also overviewed. Reference [11] performs a detailed prognostic evaluation of radio wave propagation attenuation due to rain, free space, gases, and clouds over the atmosphere at the ultra-high frequency band by employing relevant empirical atmospheric data and suitable propagation models for robust prognostic modeling using experimental measurements.