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This position paper explores the challenges and opportunities for high-quality immersive volumetric video streaming for multiple users over millimeter-wave (mmWave) WLANs. While most of the previous work has focused on single-user streaming, there is a growing need for multi-user immersive applications such as virtual collaboration, classroom education, teleconferencing, etc. While mmWave wireless links can provide multi-gigabit per second data rates, they suffer from blockages and high beamforming overhead. This paper investigates an environment-driven approach to address the challenges. It presents a comprehensive research agenda that includes developing a collaborative 3D scene reconstruction process, material identification, ray tracing, blockage mitigation, and cross-layer multi-user video rate adaptation. Our preliminary results show the feasibility and identify the limitations of existing solutions. Finally, we discuss the open challenges of implementing a practical system based on the proposed research agenda. 

With MIMO and enhanced beamforming features, IEEE 802.11ay is poised to create the next generation of mmWave WLANs that can provide over 100 Gbps data rate. However, beamforming between densely deployed APs and clients incurs unacceptable overhead. On the other hand, the absence of up-to-date beamforming information restricts the diversity gains available through MIMO and multi-users, reducing the overall network capacity. This paper presents a novel approach of "coordinated beamforming" (called CoBF) where only a small subset of APs are selected for beamforming in the 802.11ay mmWave WLANs. Based on the concept of uncertainty, CoBF predicts the APs whose beamforming information is likely outdated and needs updating. The proposed approach complements the existing per-link beamforming solutions and extends their effectiveness from link-level to network-level. Furthermore, CoBF leverages the AP uncertainty to create MU-MIMO groups through interference-aware scheduling in 802.11ay WLANs. With extensive experimentation and simulations, we show that CoBF can significantly reduce beamforming overhead and improve network capacity for 802.11ay WLANs. 

Roofers spend considerable time in awkward postures due to steep-slope rooftops. The combination of these postures, the forces acting on them, and the time spent in such postures increases the chance of roofers developing musculoskeletal disorders (MSDs). Several studies have connected these awkward postures to potential risk factors for injuries and disorders; however, existing models are not appropriate in roof workplaces because they are designed to assess work-related risk factors for general tasks. This study examines the impacts of work-related factors, namely working posture and roof slope, on kinematics measurements of body segments in a laboratory setting. To achieve this objective, time-stamped motion data from inertial measurement unit (IMU) devices (i.e., accelerometer, gyroscope, and quaternion signals) were collected from a sample of six undergraduate students at George Mason University. Participants performed two common roofing activities, namely walking along the roof and squatting in different roof slopes (0°, 30°). Comparing IMU signals using statistical analysis demonstrated significant differences in body kinematics between roofing activities on the slope and level ground. Overall, sloped-surface activities on a 30° roof resulted in changes in about 26% of walking and 12% of squatting variables. Such information is useful for a logical understanding of roofing MSD development and may lead to better interventions and guidelines for reducing roofing injuries.