The abundant bandwidth in the mmWave band supports high data rates and low latency communication, making it ideal for delivering realistic and seamless virtual reality experiences. However, a key challenge lies in adapting the mmWave beams to the highly dynamic user movements, which often cause beam misalignment, resulting in signal degradation and potential outages. Additionally, maintaining uninterrupted signal reception during beam re-alignment due to head rotation requires low-overhead and timely beam transitions to prevent signal drops caused by delayed switching. This paper addresses these challenges with a joint solution at both the access point (AP) and head-mounted display (HMD) ends. Specifically, the proposed solution integrates coordinated multi-point networks with dual-beam reception at the HMD to enhance diversity, improve channel gain, and mitigate outages caused by user movement. Evaluation using real HMD movement datasets demonstrates that dual-beam reception within a coordinated multi-AP setup achieves up to a 22.8% improvement in reliability by reducing outage rates compared to single-beam reception. Experimental validation further highlights the effectiveness of combining widely distributed APs with a locally distributed subarray configuration on the HMD, improving angular coverage during head rotations. Furthermore, our predictive beam transition approach anticipates the future beam during user movements, preventing received signal degradation from delayed transitions while reducing overhead by 43.8% compared to exhaustive periodic beam searches.

This paper introduces an Integrated Sensing and Communication (ISAC) approach to safeguard communication User Equipment (UE) from approaching objects or people, such as potential blockers, without the need to scan the entire environment, while providing continuous communication services. The proposed UE-centered ISAC system utilizes a communication-centric waveform, transmitted through guard beams to monitor the area within the UE proximity. These guard beams are generated through a multi-beamforming technique employing a shared analog array that also generates the communication beam. The parameters for generating the guard beams are optimized to maximize sensing coverage while adhering to the communication Signal-to-Noise Ratio (SNR) constraints. In comparison to the detection using the communication-beam-only system, our optimized guard beams enhance the detection range and coverage area by over 1.5 times while maintaining the required communication SNR. Our multi-stage sensing pipeline applied to the guard beams significantly reduces the complexity of sensing signal processing required to detect approaching blockers while maintaining accuracy comparable to that of exhaustive scanning based on the grid-searching method. Furthermore, the guard beams approach reduces the impact on communication SNR by 0.7 dB factor compared to exhaustive scanning with a balanced communication-sensing power allocation, offering a less pronounced impact on the communication performance in an ISAC system.