A High-Diversity Transceiver Design for MISO Broadcast Channels

In this paper, the outage behavior and diversity order of the mixture transceiver architecture for multiple-input single-output broadcast channels are analyzed. The mixture scheme groups users with closely-aligned channels and applies superposition coding and successive interference cancellation decoding to each group composed of users with closely-aligned channels, while applying zero-forcing beamforming across semi-orthogonal user groups. In order to enable such analysis, closed-form lower bounds on the achievable rates of a general multiple-input single-output broadcast channel with superposition coding and successive interference cancellation are newly derived. By employing channel-adaptive user grouping and proper power allocation, which ensures that the channel subspaces of user groups have angle larger than a certain threshold, it is shown that the mixture transceiver architecture achieves full diversity order in multiple-input single-output broadcast channels and opportunistically increases the multiplexing gain while achieving full diversity order. Furthermore, the achieved full diversity order is the same as that of the single-user maximum ratio transmit beamforming. Hence, the mixture scheme can provide reliable communication under channel fading for ultra-reliable low latency communication. Numerical results validate our analysis and show the outage superiority of the mixture scheme over conventional transceiver designs for multiple-input single-output broadcast channels.Comment: The inner region is evaluated. The single-group SIC performance is evaluate

Interpretable Housing for Freedom of the Body: The Next Generation of Flexible Homes

If we have gone through the first generation of housing design that pursued functional optimization, ergonomics, and circulation efficiency during the last century, now we are living in the second generation where more advanced goals, such as universal design, ubiquitous design, sustainable design, and environment-friendly design, are emphasized. Al-though this second generation of design focuses upon the wellness of humans in accordance with environment, it still has the attitude that a more precisely designed home can guarantee a better life. What lacks in this approach is the free-dom of the body; it needs to make its own choice as to how to use a space. Thus, it is suggested in this paper that what is important in designing a home is to provide alternatives in daily lives so as to make a full exploration of a given space. These alternatives can be made by offering residents an interpretable space where they can figure out space usages and routs in a constantly changing context. Two spatial devices are discussed in depths as a way to realize this interpretable house: room-to-room enfilade and ring spatial structure. By investigating some existing house plans, it is illustrated how they can guarantee the freedom of the body, and thus alternatives for the flexible domestic life

Pilot Beam Sequence Design for Channel Estimation in Millimeter-Wave MIMO Systems: A POMDP Framework

In this paper, adaptive pilot beam sequence design for channel estimation in large millimeter-wave (mmWave) MIMO systems is considered. By exploiting the sparsity of mmWave MIMO channels with the virtual channel representation and imposing a Markovian random walk assumption on the physical movement of the line-of-sight (LOS) and reflection clusters, it is shown that the sparse channel estimation problem in large mmWave MIMO systems reduces to a sequential detection problem that finds the locations and values of the non-zero-valued bins in a two-dimensional rectangular grid, and the optimal adaptive pilot design problem can be cast into the framework of a partially observable Markov decision process (POMDP). Under the POMDP framework, an optimal adaptive pilot beam sequence design method is obtained to maximize the accumulated transmission data rate for a given period of time. Numerical results are provided to validate our pilot signal design method and they show that the proposed method yields good performance.Comment: 6 pages, 6 figures, submitted to IEEE ICC 201

Implications of the dark axion portal for the muon g-2, B-factories, fixed target neutrino experiments and beam dumps

The dark axion portal is a recently introduced portal between the standard model and the dark sector. It connects both the dark photon and the axion (or axion-like particle) to the photon simultaneously through an anomaly triangle. While the vector portal and the axion portal have been popular venues to search for the dark photon and axion, respectively, the new portal provides new detection channels if they coexist. The dark axion portal is not a result of the simple combination of the two portals, and its value is not determined by the other portal values; it should be tested independently. In this paper, we discuss implications of the new portal for the leptonic g-2, B-factories, fixed target neutrino experiments, and beam dumps. We provide the model-independent constraints on the axion-photon-dark photon coupling and discuss the sensitivities of the recently activated Belle-II experiment, which will play an important role in testing the new portal.Comment: 14 pages, 12 figures. v2 - Additional discussion and references added. v3 - Version accepted for publication by PRD. v4 - Correction to equation following Eq. (15

Searching through Videos: Scholarly Information Search of Native and Non-Native English Speakers on YouTube

Living in a visually rich environment, university students seek and con-sume information through videos to complete their academic tasks. This exploratory pilot study examines if and how students’ interaction with the YouTube search engine will generate particular search experiences and out-comes on their search tasks, and how native and non-native English-speaking students may interact with the search system and the videos. It aims to explore possible patterns in the search behaviors and experiences of the two groups. One general exploratory information task and the partici-pants’ self-selected academic-oriented tasks were used for this study, both of which have been observed and analyzed along with follow-up interviews. Initial patterns have been observed in their behaviors within the search en-gine on their academic-oriented tasks. Limitations and suggestions for fur-ther development of the design of the research are discussed