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Item type:Publication, Access status: without files , Modeling the impact of bursty traffic on end-to-end delays in 6TiSCH wireless sensor networksNew applications emerge for Wireless Sensor Networks (WSNs), e.g., monitoring and surveillance, producing bursty traffic which greatly impacts communication network performance. The latter can be evaluated through simulations or experiments, both of which are more time-consuming and costly than analytical models. Reliable communication in WSNs is achievable through IEEE 802.15.4 Timeslotted Channel Hopping (TSCH). Accurately evaluating its performance under bursty traffic is critical to plan future networks. This letter proposes a framework for modeling the impact of bursty traffic on end-to-end delays in TSCH networks, using queuing theory and Markov chains. Simulations in OMNeT++ validate framework accuracy with <1% normalized Root Mean Squared Error (RMSE).Publicationtype: Journal Article17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Spatiotemporal Dependable Task Execution Services in MEC-Enabled Wireless SystemsMulti-access Edge Computing (MEC) enables computation and energy-constrained devices to offload and execute their tasks on powerful servers. Due to the scarce nature of the spectral and computation resources, it is important to jointly consider i) contention-based communications for task offloading and ii) parallel computing and occupation of failure-prone MEC processing resources (virtual machines). The feasibility of task offloading and successful task execution with virtually no failures during the operation time needs to be investigated collectively from a combined point of view. To this end, this letter proposes a novel spatiotemporal framework that utilizes stochastic geometry and continuous time Markov chains to jointly characterize the communication and computation performance of dependable MEC-enabled wireless systems. Based on the designed framework, we evaluate the influence of various system parameters on different dependability metrics such as (i) computation resources availability, (ii) task execution retainability, and (iii) task execution capacity. Our findings showcase that there exists an optimal number of virtual machines for parallel computing at the MEC server to maximize the task execution capacity.Publicationtype: Journal Article80 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An ordering scheme exploiting modulation information for tree search based detection in interference-limited MIMO systemsThe well-known vertical Bell Labs layered space-time (V-BLAST) ordering has been widely employed for tree search algorithms such as sphere decoder. The V-BLAST ordering was derived under the assumption that all transmitted symbols utilize the same modulation. In an interference-limited scenario, a cell-edge user probably receives serving and interfering signals with different modulations. In this case, the conventional V-BLAST ordering does not provide a satisfactory solution for complexity reduction. This letter shows how to incorporate the modulation information into the V-BLAST ordering to significantly reduce the complexity of the tree search algorithms. Simulation results show the new ordering based sphere decoder can provide a better trade-off between complexity (e.g., in terms of operations) and performance (e.g., in terms of throughput or error rate) in the interference-limited scenario.Publicationtype: Journal Article35