Abstract：In broadband Multiple Input Multiple Output (MIMO) communication systems, the use of a uniform circular array (UCA) at the base station introduces a significant near-field beam-splitting phenomenon due to the array's wide bandwidth and large-scale antenna characteristics. This renders traditional fast beam training methods based on phase shifter (PS) beamforming ineffective in broadband environments. This paper first demonstrates that the beam-splitting effect in the UCA architecture is controllable. Specifically, by introducing time delay (TD) beamforming, the extent of near-field beam splitting can be effectively adjusted. Building on this, a novel fast broadband beam training strategy is designed. The scheme employs TD beamforming to simultaneously generate beams at multiple frequencies, each focused on distinct locations in three-dimensional space. The training is conducted in two stages: the first stage searches for the user's azimuth information, and the second stage searches for the user's distance and elevation information. Simulation results show that the proposed scheme has a low training overhead of only 1 051, while its average achievable rate reaches 96.28% of the perfect channel state information benchmark.

Abstract：Aiming at the severe threat of unmanned aerial vehicle (UAV) “black flight” to the safe operation of substations, as well as the problems of low positioning accuracy, weak anti-interference ability and poor scene adaptability of traditional low-altitude protection technologies, this paper proposes a precise parameter estimation algorithm for low-altitude UAVs in power grids based on 5th Generation-Advanced (5G-A) integrated sensing and communication（ISAC）. First, a perception parameter system covering UAV motion characteristics and electromagnetic scattering characteristics is constructed, and a positioning environment reconstruction parameter system including interference signal power spectral density, multipath attenuation coefficient and signal occlusion rate is designed. Environmental adaptation is realized through the process of "parameter collection - model correction - error compensation". Finally, a two-stage continuous time-delay-Doppler channel parameter estimation algorithm of "2D orthogonal matching pursuit (2D-OMP) sparse coarse estimation + continuous domain golden section fine estimation" is proposed to solve the problems of grid mismatch and high complexity of traditional algorithms. The results show that the root mean square error (RMSE) of velocity estimation of the proposed algorithm remains optimal. Compared with the traditional single pilot estimation and one-step search algorithms, the accuracy is improved by about 55% and 33% respectively, which can achieve the target perception of decimeter-level positioning and low false alarm rate. The research results provide a high-precision and high-reliability technical scheme for low-altitude safety protection of substations, and also lay a foundation for the large-scale application of 5G-A technology in t

Abstract：To address the limitations of existing amplitude phase shift keying (APSK) modulation schemes in satellite communications, specifically their reliance on commercial chips or FPGA implementations and performance evaluations confined to ideal Gaussian channels, this study proposes a dynamically reconfigurable verification framework based on an open-source software defined radio (SDR) platform. Aligned with the DVB-S2 standard, a joint simulation system for high-order modulation and satellite channels is constructed on the GNU Radio platform. This system supports flexible configuration of 16APSK and 32APSK modulation-demodulation links and deeply integrates Loo and Corazza models to accurately emulate multipath delay, shadow fading, and Doppler shift characteristics. End-to-end hardware-in-the-loop validation from baseband generation to RF transceiver operations and receiver demodulation is implemented via the HackRF SDR hardware platform. Adopting a modular design, the system enables dynamic switching of modulation orders and channel parameters, overcoming reconfiguration constraints inherent in closed-source systems. This framework provides a scalable testbed for evaluating spectral efficiency, fading resilience, and power amplifier nonlinearity adaptability of high-order modulation techniques in 6G integrated space-ground networks.

Abstract：For the research on the expansion of marine area communication coverage, deploying small base stations(SBSs) inside ships reduces the penetration loss for cabin. However, the marine limits the wired backhaul for SBSs via internet protocol radio access network(IPRAN) or STN to transmit data back to the core network on land. Moreover, ordinary customer premise equipment(CPE) for backhaul of SBSs has low power and limited uplink transmission. Therefore, to solve marine communication problem, a scheme for expanding 5G coverage is proposed via introducing high-power CPE and high-gain servo antenna systems for heterogeneous network based on the macro BS(MBS) near coast and SBSs in marine areas. The high-power CPE provides backhaul for SBSs in cabin with wired connection. The servo antenna system is used to enhance uplink(UL) for the CPE to connect to the MBS. In particular, the list information about MBS is used for the wireless network searching process of multiple user equipments(UEs), and optimizes the target shore-based cell access algorithm for the servo antenna through collaboration of multiple UEs. The current network results show good performance for the scheme proposed.

Abstract：To meet the demands of emerging services such as global seamless coverage, emergency communications, IoT, and aviation and maritime applications, 3GPP Release 19 has systematically enhanced NTN. Compared to the transparent forwarding-dominated architecture in Release 18, 3GPP R19 NR NTN introduced a novel onboard regeneration processing architecture for the first time, enabling flexible deployment of RAN and core network functions on satellites. This significantly reduces end-to-end latency and enhances system capacity. The 3GPP R19 NR NTN access network standard has been enhanced and expanded in multiple aspects compared to Release 18, making the 6G technical solution more comprehensive and further strengthening its capabilities, thereby providing a solid technical foundation for the commercialization of 5G NR NTN. This paper takes the challenges faced in the current development of 6G satellite Internet as the starting point and focuses on analyzing aspects such as the core architecture of R19 NR NTN, air interface and performance optimization, mobility and service continuity, terminal and scenario expansion, etc. Finally, the technological development of R20 was prospected.

Abstract：As the infrastructure in the field of information and communication, 5G communication base station meets people's basic needs for daily call and traffic use. In response to the national "3060" dual-carbon strategy, the communication base station needs to change the traditional power supply mode, introduce green energy such as photovoltaic system and energy storage battery, and realize the "green, energy-saving and low-carbon" development. Under different power conditions, how to plan photovoltaic and energy storage configuration has become an important research direction in the field of information and communication. This paper innovates the simulated photovoltaic function model, explores the optimal method of light storage configuration under different power conditions, innovates the charging and discharging method of optical storage system, and realizes the maximum benefit of green energy application.

Abstract：This paper establishes a millimeter-wave channel model for unmanned aerial vehicles based on line-of-sight probability using the ray tracing method, and a double-slope model analysis is carried out for path loss. This paper describes the modeling process of line-of-sight probability and carries out model parameter analysis. Due to the influence of terrain occlusion and other environments, the reflection and bypassing paths with large losses cause the received strength of the signal to fluctuate greatly before and after the mutation point, which makes the single-slope fit model no longer applicable. Therefore, this paper uses linear regression to fit the single-slope and double-slope received power models to the simulation data under two types of terrain, and analyzes the fitting effect of the two models. The results show that the dual-slope received power model fits better than the single-slope model, and the two models have higher fitting accuracy when the terrain is more flatten.

Abstract：As an important component of 6G communication technology, the Low Earth Orbit (LEO) distributed satellite network can achieve high-speed transmission and low-latency communication, and meet the high-speed and low-latency requirements of 6G communication technology. This paper addresses the networking method of LEO distributed satellite networks. The routing algorithms of the satellite network are summarized. A joint routing algorithm based on bandwidth and delay is proposed, and three different routing algorithms are implemented to select. It is found that the performance of each algorithm is obviously different. The experimental results show that the joint algorithm based on bandwidth and delay can better balance the network load and reduce the delay while selecting the best path, and improve the transmission efficiency of satellite network.

Abstract：The 5G era is approaching with the gradual increase in deployment density of 5G devices, the cost price is too high from the perspective of simply increasing the deployment of macro base stations. On the other hand, the demand for personalized of 5G to B and to C is gradually increasing. In response to the issues of 5G frequency band heightening, penetrate walls ability reducing and personalized requirements increasing, 5G integrated small base stations has emerged, gradually improving its effectiveness in the field of supplement to blindness and heat. Pointing at the issue of communication difficulties in water operation, a new network method based on CPE is proposed. This method is easy to install and cost-effective, which can greatly meet the needs of users and be widely promoted.