查看更多>>摘要：The simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is regarded as a promising paradigm for enhancing the connectivity and reliability of non-orthogonal multiple access (NOMA) networks. However, the transmission of STAR-RIS enhanced NOMA networks performance is severely limited due to the inter-user interference (IUI) on multi-user detections. To mitigate this drawback, we propose a generalized quadrature spatial modulation (GQSM) aided STAR-RIS in conjunction with the NOMA scheme, termed STAR-RIS-NOMA-GQSM, to improve the performance of the corresponding NGMA network. By STAR-RIS-NOMA-GQSM, the information bits for all users in transmission and reflection zones are transmitted via orthogonal signal domains to eliminate the IUI so as to greatly improve the system performance. The low-complexity detection and upper-bounded bit error rate (BER) of STAR-RIS-NOMA-GQSM are both studied to evaluate its feasibility and performance. Moreover, by further utilizing index modulation (IM), we propose an enhanced STAR-RIS-NOMA-GQSM scheme, termed E-STAR-RIS-NOMA-GQSM, to enhance the transmission rate by dynamically adjusting reflection patterns in both transmission and reflection zones. Simulation results show that the proposed original and enhanced scheme significantly outperform the conventional STAR-RIS-NOMA and also confirm the precision of the theoretical analysis of the upper-bounded BER.
查看更多>>摘要：With the development of wireless communication, the fifth generation mobile communication technology (5G) has emerged as a hot topic in highspeed railway communication system and has moved towards industrial application. Investigating the radio propagation characteristics in 5G high-speed train (HST) scenarios is essential for enhancing wireless coverage and overall system performance. We propose a novel 5G passive sounding scheme to extract channel impulse responses (CIRs) using channel state information reference signals (CSI-RS) from the target 5G base station (BS). Detailed procedures for time-frequency synchronization, CSI-RS detection and extraction are presented through simulations. Through the laboratory work involving absolute power calibration, phase coherence calibration and power delay profile (PDP) validation, we validate the accuracy and performance of the developed platform. Furthermore, a measurement campaign was conducted in HST scenarios encompassing both residential and undeveloped areas. The path loss (PL) model and the channel characteristics including stationarity interval (SI), multipath components (MPCs), shadow fading (SF), Rician K-factor, root mean square (RMS) delay spread and received correlation coefficients are analyzed and fitted. The estimated channel characteristics and the statistical model presented in this paper will contribute to the research on HST radio propagation and the development of 5G railway communication systems.
查看更多>>摘要：With the continuous advancement of communication and unmanned aerial vehicle (UAV) technologies, the collaborative operations of diverse platforms, including UAVs and ground vehicles, have been significantly promoted. However, battlefield uncertainties, such as equipment failures and enemy attacks, can impact these collaborative operations' stability and communication efficiency. To this end, we design a highly destruction-resistant air-ground cooperative resilient networking platform that aims to enhance the robustness of network communications by integrating ground vehicle information for UAV network deployment. It then incorporates the concept of virtual guiding force, enabling the UAV swarm to adaptively configure its network layout based on ground vehicle information, thereby improving network destruction resistance. Simulation results demonstrate that the UAV swarm involved in the proposed platform exhibits balanced flight energy consumption and excellent performance in network destruction resistance.
查看更多>>摘要：The sixth-generation (6G) networks will consist of multiple bands such as low-frequency, midfrequency, millimeter wave, terahertz and other bands to meet various business requirements and networking scenarios. The dynamic complementarity of multiple bands are crucial for enhancing the spectrum efficiency, reducing network energy consumption, and ensuring a consistent user experience. This paper investigates the present researches and challenges associated with deployment of multi-band integrated networks in existing infrastructures. Then, an evolutionary path for integrated networking is proposed with the consideration of maturity of emerging technologies and practical network deployment. The proposed design principles for 6G multi-band integrated networking aim to achieve on-demand networking objectives, while the architecture supports full spectrum access and collaboration between high and low frequencies. In addition, the potential key air interface technologies and intelligent technologies for integrated networking are comprehensively discussed. It will be a crucial basis for the subsequent standards promotion of 6G multi-band integrated networking technology.
查看更多>>摘要：An adaptive dispersion estimation (ADE) is proposed to compensate dispersion and estimate the transfer function of the fiber channel with Gerchberg-Saxton (G-S) algorithm, using the stochastic gradient descent (SGD) method in the intensity-modulation and direct-detection (IM-DD) system, improving the tolerance of the algorithm to chromatic dispersion (CD). In order to address the divergence arising from the perturbation in the amplitude of the received signal caused by the filtering effect of the non-ideal channels, a channel-compensation equalizer (CCE) derived from the back-to-back (BTB) scenario is employed at the transmitter to make the amplitude of the received signal depicting the CD effect more accurately. The simulation results demonstrate the essentiality of CCE for the convergence and performance improvement of the G-S algorithm. Results show that it supports 112 Gb/s four-level pulse amplitude modulation (PAM4) over 100 km standard single-mode fiber (SSMF) transmission under the 7% forward error correction (FEC) threshold of 3.8E-3. Besides, ADE improves the tolerance to wavelength drift from about 4 nm to 42 nm, and there is a better tolerance for fiber distance perturbation, indicating the G-S algorithm and its derived algorithms with the ADE scheme exhibit superior robustness to the perturbation in the system.
NETL
NSTL
China Inst Communications