The reconfigurable intelligent surface (RIS) stands as an emergent technique poised to revolutionize future vehicular communication. In order to facilitate the application of RIS in vehicular communication, this paper proposes two effective RIS-aided schemes tailored for polarization modulation (PM) aiming to achieve remarkable spectral efficiency. Specifically, Scheme I proposes a novel index modulation (IM) aided PM-RIS framework that innovatively encodes information across three distinct dimensions, the indices of dual-polarized antennas (DP-AEs), PM symbols and the reflecting surface indices of the RIS. Scheme II employs a deep neural network method to analyze the channel state information (CSI) for transmit antenna selection, that enhances the reliability and interference immunity in dynamic conditions while reducing computational complexity. Furthermore, a stepwise estimation (SE) method is introduced at the detection stage, which significantly reduces the complexity associated with information decoding. The simulation results highlight the superiority of the proposed system. Compared with traditional PM systems, it demonstrates enhanced performance in terms of spectral efficiency, channel stability, and bit error rate (BER).

The reconfigurable intelligent surface (RIS)-aided vehicle road cooperation (VRC) scheme is a promising technique. However, the security issue of the RIS-VRC systems is still a crucial problem due to the high connectivity of multiple vehicles under the broadcasting environment. Within this study, based on the potential of the RIS-VRC system, a novel low-complexity consecutive artificial noise (CAN) with legal channel state information (CSI) and a low-cost and spectral-efficient secure index modulation (IM) design physical layer security (PLS) scheme is detailed. Specifically, an information symbol consisting of a modulation symbol and AN devised based on the CSI of the legitimate link across two consecutive time intervals is transmitted. At the receiver, the decoding scheme relies on two consecutive time intervals which can enable the ideal elimination of AN solely at the authorized vehicle is proposed. Nevertheless, given the independence of the CSI for the legitimate links and the illegitimate links, the unauthorized vehicle remains vulnerable to AN interference. Moreover, the antenna selection method based on minimum Euclidean distance (MED-TAS) is proposed to guarantee the requisite number of transmitting antennas for IM. Finally, the expressions of the secrecy rate are deduced by considering the disparity in the attainable mutual information between the authorized vehicle and the eavesdropping vehicle. Compared with traditional PLS schemes, the numerical outcomes affirm the capability of the proposed scheme to attain enhanced security performance with much lower complexity.

Communication is one of the most important foundations in the Internet of Things. Although some cutting‐edge technologies, such as 5G, have greatly empowered edge computing, electromagnetic interference and pollution make them impracticable in many environments. The visible light communication (VLC) is a new type of wireless communication technology with appealing benefits not presented in radio communications. VLC allows a lamp or other light source to not only serve as illumination but also simultaneously transmit data. Although traditional VLC multiplexing technologies have been able to achieve a high‐speed data transmission rate, they require all receivers to use the same modulation means. In many scenarios, various‐type receivers coexist; it is costly to incorporate multiple senders to implement adaptive content distribution in on‐demand services. In this paper, we propose a new type of VLC multiplexing system, which realizes end‐edge data transmission through pulse position modulation (PPM), pulse width modulation (PWM), and pulse amplitude modulation (PAM) simultaneously. Therefore, one edge server can serve multiple types of end‐users without interference. In order to evaluate the performance of the system, we conduct experiments with different settings of communication distance, communication angle, and different environmental light conditions. For three modulations, the proposed system can achieve a transmission speed three times as that for a single modulation, and reach the accuracy rate of up to 99% within the proper communication range.

As one of the emerging technologies for the 5th generation (5G) mobile communication system, the ultra-dense network (UDN) effectively solves the problems of seamless handover in the network and blind spot coverage. In the UDN, 3rd generation partnership project (3GPP) has recognized coordinated multi-point (CoMP) and multi- connectivity are two common technologies to improve resource utilization. CoMP is traditionally in-band while multi-connectivity is across bands. CoMP mostly serves to improve signal-to-interference- plus-noise ratio (SINR) via beamforming or via joint transmission/reception while multi-connectivity mostly serves to provide coverage holes with different spectrums and improve reliability. However, there has been no performance comparison between multi-connectivity and CoMP. Therefore, in this study, performance evaluation between multi- connectivity and CoMP is conducted under UDN scenarios. The results show that the performance of multiconnectivity at low user density is better than that at high user density. Moreover, compared with the CoMP transmission system, multi-connectivity can increase the user average throughput at low user density scenarios. The performance of multi- connectivity depends on the user density, the collaborative set number, and the user equipment speed.