Summary Multiuser multi‐in multi‐out (MU‐MIMO) technology using the fifth generation mobile network (5G) massive antenna can greatly increase the existing network capacity and help address problems related to large increases in network traffic. In this study, massive MIMO multiuser space division multiplexing based on transmission mode 3 (TM3) is realized by dividing massive MIMO antenna into virtual beam and fan section. Then the performance evaluations on the MU‐MIMO system in practical existing networks were conducted. The results showed that this technology can realize three times the amount of spatial multiplexing while still maintaining good mobility performance in a no‐load network. In addition, the capacity of the cell can be increased by the massive MIMO system in an existing network for a large user population (for a space division multiplexing factor of approximately 1.83). Test results are used to prove the effectiveness of the frequency‐division duplex massive MIMO multiuser multiplexing based on TM3 to increase the capacity of an existing network.

Although 5G era has come, the comprehensive coverage of 5G will take a long time for the vast number of underdeveloped countries and regions. Therefore, it is still significant to improve the depth coverage of 4G network. Massive Multi-in Multi-out (MIMO) is an application of 5G key technology in 4G network. In this study, based on the theoretical principle of beamforming, a special beamforming was realized by combining precoding and direction-of-arrival (DOA) estimation of sounding reference signal (SRS) in Massive MIMO antenna. Moreover, this beamforming antenna was applied to the existing 4G network. The building of deep coverage between indoor distribution and beamforming antenna was compared. It found that beamforming antenna can gain 6-8 dB beamforming gains and the overage coverage effect is better than indoor distribution.

As the latest touch-based input equipment of consumer electronics, touch screen is a convenient and natural human-machine interaction vehicle. However, it has not separated from the scope of "interactive input". Tactile display adds the tactile output along with the interactive input and helps the operator to perceive tactile feedback of texture, profile, etc., which increases the immersion of the operator significantly. In this study, a friction-varying texture tactile display which is composed of resonance module, positioning module and vision display module was designed by using the squeeze film effect. In this device, a piece of 194×100×2 mm transparent glass was used as the touch tablet, which can provide a large working area and is easy to be integrated with common consumer electronics. The feasibility and precision of the designed friction-varying tactile display in simulation of texture were further verified by a psychophysical experiment.

The finger skin contains a variety of receptors, which provide multiple tactile sensing channels. When a finger touches the surface of an object, people can simultaneously perceive curvature, texture, softness, temperature, and so on. However, in most of research activities, the designed haptic feedback devices can only focus on a certain channel. In this paper, the rendering of curved and periodic textured surfaces involving two channels, i.e., curvature and texture, was studied. Two psychophysical experiments were conducted to investigate whether the coupling of kinesthetic feedback of curvature and tactile feedback of texture could reproduce curved and textured surfaces with high fidelity. The results showed a deviation of the point of subjective equality values in terms of curvature and roughness, indicating that the curvature rendering and texture rendering have an impact on each other. Therefore, it is necessary to correct the bias when making virtual rendering. The influence of curvature on texture rendering is reduced by recalculating and adjusting the spatial period of the synthesized texture in real-time; the influence of texture on curvature rendering is eliminate by compensating the force difference between touch on physical strip and artificial stimulus.