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In this paper, an advanced duplex scheme called cross-division duplex (XDD) is proposed to enhance uplink (UL) coverage in time division duplex (TDD) carriers by utilizing self-interference cancellation (SIC) capability at a base station. With XDD, it is possible to combine TDD’s ability to efficiently handle asymmetric UL and downlink (DL) traffic with frequency division duplex’s coverage advantage. To do so, XDD simultaneously operates UL and DL on the same TDD carrier but on different frequency resources. Such operation leads to severe interference on the received UL signal at the base station which requires two levels of SIC implementation; antenna and digital SIC. More than 50 dB of interference is removed through the antenna SIC using electromagnetic barriers between the transmitting and receiving antennas. The remaining interference is removed by the digital SIC based on estimating the non-linear channel of the circuit at the receiver baseband. It is verified by simulation and analysis that with the proposed XDD, the UL coverage can be improved by up to 2.37 times that of TDD. To check the feasibility of XDD, a Proof-of-Concept was developed where it was observed that the benefits of XDD can indeed be realized using the proposed SIC techniques.

Battery life of mobile terminals has been a key performance indicator (KPI) for user experience since the early days of wireless communications. This KPI has become even more important for fifth generation (5G) cellular systems due to higher requirements such as the support of carrier frequency up to 100 GHz, carrier bandwidth up to 400 MHz, peak data rate up to 20 Gbps, latency as small as 1 ms, and enhanced receiver performance. In response, various power saving techniques have been studied and implemented so that devices can be used over a longer period without noticeable decrease in performance. In this article, we provide a comprehensive overview of the latest terminal power saving techniques which were specified in 5G New Radio (NR) over the last couple of years. The key feature and benefit of each power saving technique is analyzed with simulation results under various traffic scenarios. In addition, some of the candidate techniques for the next phase of NR on terminal power saving enhancement are proposed targeting not only conventional data services but also various vertical services.

In this paper, we propose a new data transmission scheme called interference-aware cascade modulation (IA-CM) for advanced duplex (AD) in Beyond-5G cellular systems where downlink (DL) and uplink (UL) signals are transmitted and received simultaneously within a carrier bandwidth. In IA-CM, self-interference due to simultaneous operation of DL transmission and UL reception in a base station is handled by adapting the modulation and coding scheme (MCS) level of the UL data transmission according to the level of self-interference that has a gradual decaying profile in the frequency domain. Consequently, unlike conventional scheme where a single MCS level is used for UL data transmission throughout the assigned UL bandwidth, multiple MCS levels are used in IA-CM based UL data transmission. In the process, the base station evaluates signal-to-interference-plus-noise ratio (SINR) in frequency selective manner taking into account the interference leakage generated from non-linearity of DL transmission, coupling with UL, and self-interference cancellation capability. in Fig. 1, two-dimensional resource allocation The benefits of IA-CM are verified from evaluations and it is observed that IA-CM achieves a 30% throughput gain over the conventional scheme when AD is used.

In this paper, we propose a novel statistical beamforming (SBF) method called the partial-nulling-based SBF (PN-SBF) to serve a number of users that are undergoing distinct degrees of spatial channel correlations in massive multiple-input multiple-output (MIMO) systems. We consider a massive MIMO system with two user groups. The first group experiences a low spatial channel correlation, whereas the second group has a high spatial channel correlation, which can happen in massive MIMO systems that are based on fifth-generation networks. By analyzing the statistical signal-to-interference-plus-noise ratio, it can be observed that the statistical beamforming vector for the low-correlation group should be designed as the orthogonal complement for the space spanned by the aggregated channel covariance matrices of the high-correlation group. Meanwhile, the spatial degrees of freedom for the high-correlation group should be preserved without cancelling the interference to the low-correlation group. Accordingly, a group-common pre-beamforming matrix is applied to the low-correlation group to cancel the interference to the high-correlation group. In addition, to deal with the intra-group interference in each group, the post-beamforming vector for each group is designed in the manner of maximizing the signal-to-leakage-and-noise ratio, which yields additional performance improvements for the PN-SBF. The simulation results verify that the proposed PN-SBF outperforms the conventional SBF schemes in terms of the ergodic sum rate for the massive MIMO systems with distinct spatial correlations, without the rate ceiling effect in the high signal-to-noise ratio region unlike conventional SBF schemes.

In this paper, the scaling laws of scheduling gain and the feasibility of user scheduling for uplink massive multiple input&ndash, multiple output (MIMO) systems are investigated by analyzing the second moment of mutual information. We consider two well-known linear receivers of matched filter (MF) and zero-forcing (ZF). The exact distribution of the signal-to-interference-plus-noise ratio (SINR) and its moment-generating function are first obtained, and the approximated variance of the mutual information for a user is derived as a closed form with a function of the number of antennas. The achievable scheduling gain under the optimal user scheduler is then derived using the Gaussianity of the sum rate. From the analyses and simulation results, it is found that the scheduling gain for the MF receiver increases with the number of base station (BS) antennas, while that for the ZF receiver decreases as the number of BS antennas increases, for most cases (except some impractical scenarios). Therefore, it is verified that user scheduling is still beneficial for the MF receiver while random user selection is sufficient for the ZF receiver in massive MIMO systems.

As the automotive and AI industries are expanding rapidly, global-shutter (GS) image sensors are playing a more significant role in the perception system. More specifically, GS image sensors are required in various fields involving IR, including the face-ID in mobile devices, the driver monitoring system in automotive applications, and factory automation. GS image sensors are necessary for these applications because they can capture freeze-frame images without motion distortion due to their advantage in the pixel operation method. The simultaneous pixel exposure and in-pixel storing capability allow GS image sensors to achieve high-quality imaging, while the sequential pixel exposure and readout of rolling-shutter (RS) image sensors results in image distortion known as the jello effect. For mobile and automotive applications, a small form factor while maintaining a low parasitic light sensitivity (PLS) and low noise is crucial. In conventional backside illuminated (BSI) charge-domain GS image sensors, a light-shielding structure over the storage area must be formed in order to suppress the influence of parasitic light during the readout operation. Therefore, the introduction of such a light-shielding structure reduces the effective photodiode area, which results in a loss of full-well capacity (FWC), light sensitivity of the sensor, and pixel scalability.

Today, as greenhouse gas reduction, environmental pollution, climate change response, and power outage are emerging as social issues, the energy industry is making various efforts to diversify its supply to adapt to these changes. However, since nuclear power is a safety issue after the Fukushima nuclear power plant, wind power, wave power, and geothermal power are difficult to be used because they are difficult to use due to their difficult conditions and installation conditions. Nowadays, solar energy that is easy to install and relatively free is attracting attention. However, since solar power generation is affected by the weather, power generation is not constant and it is difficult to link grid. Therefore, this study establishes a model for predicting solar power generation, and conducts basic research to link solar power generation system with system efficiently by managing it efficiently.1