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1. Fairness and Delay in Heterogeneous Half- and Full-Duplex Wireless Networks

   https://doi.org/10.1109/ACSSC.2018.8645117  

   Chen, Tingjun; Diakonikolas, Jelena; Ghaderi, Javad; Zussman, Gil (October 2018, Conference record - Asilomar Conference on Signals, Systems, & Computers)

   Full-duplex (FD) wireless is an attractive communication paradigm with high potential for improving network capacity and reducing delay in wireless networks. Despite significant progress on the physical layer development, the challenges associated with developing medium access control (MAC) protocols for heterogeneous networks composed of both legacy half-duplex (HD) and emerging FD devices have not been fully addressed. In [1], we focused on the design and performance evaluation of scheduling algorithms for heterogeneous HD-FD networks and presented the distributed Hybrid-Greedy Maximal Scheduling (H-GMS) algorithm. H-GMS combines the centralized Greedy Maximal Scheduling (GMS) and a distributed queue-based random-access mechanism, and is throughput-optimal. In this paper, we analyze the delay performance of H-GMS by deriving two lower bounds on the average queue length. We also evaluate the fairness and delay performance of H-GMS via extensive simulations. We show that in heterogeneous HD-FD networks, H-GMS achieves$$16-30\times$$ better delay performance and improves fairness between FD and HD users by up to 50% compared with the fully decentralized Q-CSMA algorithm. 

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2. Self-Interference Cancellation and Beamforming in Repeater-assisted Full-duplex Vehicular Communication

   https://doi.org/10.1109/VTC2020-Spring48590.2020.9128558  

   Ibrahim, Ahmed S. (May 2020, 2020 IEEE 91st Vehicular Technology Conference (VTC2020-Spring))

   Self-driving vehicles will need low-latency and high-capacity vehicular communication for acquiring wider view of their surroundings. Such vehicle-to-vehicle communication can be indirectly supported in some circumstances (e.g., if blocked) through adjacent road side units (RSUs). RSUs will be acting as full-duplex repeaters among the vehicles to ensure low latency and high data rate. However, full-duplex repeaters result in self-interference phenomenon which can degrade the reliability of the communication links. In this work, we aim to enhance the reliability of full-duplex repeaters by canceling out the self-interference impact, and applying a beamforming scheme that is matched to the source-destination composite channel. We show that the proposed self-interference cancellation and beamforming (SICAB) algorithm significantly reduces the error rate for low-isolated repeaters. Finally, we illustrate the impact of the repeater isolation capability on the performance of the proposed SICAB algorithm. 

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3. Hybrid Scheduling in Heterogeneous Half- and Full-Duplex Wireless Networks

   https://doi.org/1801.01108v2  

   Tingjun Chen, Jelena Diakonikolas (January 2018, ArXiv.org)

   Full-duplex (FD) wireless is an attractive communication paradigm with high potential for improving network capacity and reducing delay in wireless networks. Despite significant progress on the physical layer development, the challenges associated with developing medium access control (MAC) protocols for heterogeneous networks composed of both legacy half-duplex (HD) and emerging FD devices have not been fully addressed. Therefore, we focus on the design and performance evaluation of scheduling algorithms for infrastructure-based heterogeneous HD-FD networks (composed of HD and FD users). We first show that centralized GreedyMaximal Scheduling (GMS) is throughput-optimal in heterogeneous HD-FD networks. We propose the Hybrid-GMS (H-GMS) algorithm, a distributed implementation of GMS that combines GMS and a queue-based random-access mechanism. We prove that H-GMS is throughputoptimal. Moreover, we analyze the delay performance of H-GMS by deriving lower bounds on the average queue length. We further demonstrate the benefits of upgrading HD nodes to FD nodes in terms of throughput gains for individual nodes and the whole network. Finally, we evaluate the performance of HGMS and its variants in terms of throughput, delay, and fairness between FD and HD users via extensive simulations. We show that in heterogeneous HD-FD networks, H-GMS achieves 16–30× better delay performance and improves fairness between HD and FD users by up to 50% compared with the fully decentralized Q-CSMA algorithm. 

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4. Hybrid scheduling in heterogeneous half- and full-duplex wireless networks

   Chen, T.; Diakonikolas, J.; Ghaderi, J.; Zussman, G. (January 2020, IEEE/ACM Transactions on Networking)

   Abstract—Full-duplex (FD) wireless is an attractive communication paradigm with high potential for improving network capacity and reducing delay in wireless networks. Despite significant progress on the physical layer development, the challenges associated with developing medium access control (MAC) protocols for heterogeneous networks composed of both legacy half-duplex (HD) and emerging FD devices have not been fully addressed. Therefore, we focus on the design and performance evaluation of scheduling algorithms for infrastructure-based heterogeneous HD-FD networks (composed of HD and FD users). We first show that centralized Greedy Maximal Scheduling (GMS) is throughput-optimal in heterogeneous HD-FD networks. We propose the Hybrid-GMS (H-GMS) algorithm, a distributed implementation of GMS that combines GMS and a queue-based random-access mechanism. We prove that H-GMS is throughputoptimal. Moreover, we analyze the delay performance of H-GMS by deriving lower bounds on the average queue length. We further demonstrate the benefits of upgrading HD nodes to FD nodes in terms of throughput gains for individual nodes and the whole network. Finally, we evaluate the performance of HGMS and its variants in terms of throughput, delay, and fairness between FD and HD users via extensive simulations. We show that in heterogeneous HD-FD networks, H-GMS achieves 16–30× better delay performance and improves fairness between HD and FD users by up to 50% compared with the fully decentralized Q-CSMA algorithm. 

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5. Cascade-Based Randomization for Inferring Causal Effects under Diffusion Interference

   https://doi.org/10.1609/icwsm.v18i1.31322  

   Fatemi, Zahra; Pouget-Abadie, Jean; Zheleva, Elena (May 2024, Proceedings of the International AAAI Conference on Web and Social Media)

   The presence of interference, where the outcome of an individual may depend on the treatment assignment and behavior of neighboring nodes, can lead to biased causal effect estimation. Current approaches to network experiment design focus on limiting interference through cluster-based randomization, in which clusters are identified using graph clustering, and cluster randomization dictates the node assignment to treatment and control. However, cluster-based randomization approaches perform poorly when interference propagates in cascades, whereby the response of individuals to treatment propagates to their multi-hop neighbors. When we have knowledge of the cascade seed nodes, we can leverage this interference structure to mitigate the resulting causal effect estimation bias. With this goal, we propose a cascade-based network experiment design that initiates treatment assignment from the cascade seed node and propagates the assignment to their multi-hop neighbors to limit interference during cascade growth and thereby reduce the overall causal effect estimation error. Our extensive experiments on real-world and synthetic datasets demonstrate that our proposed framework outperforms the existing state-of-the-art approaches in estimating causal effects in network data. 

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