mmWave communication has been recognized as a highly promising technology for 5G wireless backhaul, which is capable of providing multi-gigabit per second transmission rates. However, in urban wireless backhaul environments, unforeseen events can cause short-term blockages or node failures and, therefore, network survivability is extremely important. In this paper, we investigate a novel relay-assisted mmWave backhaul network architecture, where a number of small-cell BSs and relays are deployed, e.g. on the lampposts of urban streets. Relays are used to provide multi-hop line-of-sight paths between small-cell BSs, which form logical links of the network. In this scenario, the interconnected logical links make up a mesh network, which offers opportunities for both link-level and network-level reconfiguration. We propose two joint link-network level reconfiguration schemes for recovery after exceptional events. One prioritizes relay path (link-level) reconfiguration and uses alternate network-level paths only if necessary. The other splits traffic on both reconfigured links and backup paths to improve network throughput. Simulation results demonstrate that the proposed schemes significantly outperform purely link-level and purely network-level reconfiguration schemes. The proposed approaches are shown to not only maintain high network throughput but to also provide robust blockage/fault tolerance across a range of scenarios for urban mmWave backhaul networks.
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mmChoir: Exploiting Joint Transmissions for Reliable 60GHz mmWave WLANs
60 GHz millimeter-wave WLANs are gaining traction with their ability to provide multi-gigabit per second data rates. In spite of their potential, link outages due to human body blockage remain a challenging outstanding problem. In this work, we propose mmChoir, a novel proactive blockage mitigation technique that utilizes joint transmissions from multiple Access Points (APs) to provide blockage resilience to clients. We derive a new reliability metric based on angular spread of incoming paths to a client and their blockage probabilities. The metric can be used to intelligently select joint transmissions that can provide higher reliability. The reliability metric along with a novel interference estimation model, is used by mmChoir's scheduler to judiciously schedule joint transmissions, and increase network capacity and reliability. Our testbed and trace-driven simulations show that mmChoir can outperform existing beamswitching based blockage mitigation scheme with on an average 58% higher network throughput.
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- NSF-PAR ID:
- 10075911
- Date Published:
- Journal Name:
- ACM Mobihoc '18 Proceedings of the Eighteenth ACM International Symposium on Mobile Ad Hoc Networking and Computing
- Page Range / eLocation ID:
- 251 to 260
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Introduction Non‐routine events (NREs) are atypical or unusual occurrences in a pre‐defined process. Although some NREs in high‐risk clinical settings have no adverse effects on patient care, others can potentially cause serious patient harm. A unified strategy for identifying and describing NREs in these domains will facilitate the comparison of results between studies.
Methods We conducted a literature search in PubMed, CINAHL, and EMBASE to identify studies related to NREs in high‐risk domains and evaluated the methods used for event observation and description. We applied The Joint Commission on Accreditation of Healthcare Organization (JCAHO) taxonomy (cause, impact, domain, type, prevention, and mitigation) to the descriptions of NREs from the literature.
Results We selected 25 articles that met inclusion criteria for review. Real‐time documentation of NREs was more common than a retrospective video review. Thirteen studies used domain experts as observers and seven studies validated observations with interrater reliability. Using the JCAHO taxonomy, “cause” was the most frequently applied classification method, followed by “impact,” “type,” “domain,” and “prevention and mitigation.”
Conclusions NREs are frequent in high‐risk medical settings. Strengths identified in several studies included the use of multiple observers with domain expertise and validation of the event ascertainment approach using interrater reliability. By applying the JCAHO taxonomy to the current literature, we provide an example of a structured approach that can be used for future analyses of NREs.
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3209582.3209608
