1,720,966 research outputs found
Resource Management for 5G NR Integrated Access and Backhaul: a Semi-centralized Approach
Full text linkThe next generations of mobile networks will be deployed as ultra-dense networks, to match the demand for increased capacity and the challenges that communications in the higher portion of the spectrum (i.e., the mmWave band) introduce. Ultra-dense networks, however, require pervasive, high-capacity backhaul solutions, and deploying fiber optic to all base stations is generally considered to be too expensive for network operators. The 3gpp has thus introduced iab, a wireless backhaul solution in which the access and backhaul links share the same hardware, protocol stack, and also spectrum. The multiplexing of different links in the same frequency bands, however, introduces interference and capacity sharing issues, thus calling for the introduction of advanced scheduling and coordination schemes. This paper proposes a semi-centralized resource allocation scheme for iab networks, designed to be flexible, with low complexity, and compliant with the 3gpp iab specifications. We develop a version of the mwm problem that can be applied on a spanning tree that represents the iab network and whose complexity is linear in the number of iab-nodes. The proposed solution is compared with state-of-the-art distributed approaches through end-to-end, full-stack system-level simulations with a 3gpp-compliant channel model, protocol stack, and a diverse set of user applications. The results show that our scheme can increase the throughput of cell-edge users up to 3 times, while decreasing the overall network congestion with an end-to-end delay reduction of up to 25 times
Toward Standardization of Millimeter-Wave Vehicle-to-Vehicle Networks: Open Challenges and Performance Evaluation
No full textIEEE 802.11bd and 3GPP NR V2X represent the new specifications for next generation vehicular networks, exploiting new communication technologies and new spectrum, such as the millimeter-wave (mmWave) band, to improve throughput and reduce latency. In this article, we specifically focus on the challenges that mmWaves introduce for vehicle-to-vehicle (V2V) networking, by reviewing the latest standard developments and the issues that 802.11bd and NR V2X will have to address for V2V operations at mmWaves. To the best of our knowledge, our work is the first that considers a full-stack, end-toend approach for the design of mmWave V2V networks, discussing open issues that span from the physical to the higher layers, and reporting the results of an end-to-end performance evaluation that highlight the potential of mmWaves for V2V communications
Extending the ns-3 spatial channel model for vehicular scenarios
No full textThe next generation of wireless systems will enable vehicles to communicate among themselves and with the surrounding environment, thus providing the possibility to build cooperative and intelligent transportation systems. To design communication technologies that can cope with the requirements envisioned for future vehicular services, we need specific simulation tools to evaluate the system performance from an end-to-end perspective. Being one of the best known open-source network simulators, ns-3 represents the perfect candidate to perform this task. In this work, we describe the extension of the ns-3 Spatial Channel Model to enable the modeling of wireless channels in vehicular environments. Such extension is compliant with the 3GPP TR 37.885 specification and has been designed to be flexible and modular, thus improving the support for the simulation of next generation wireless systems
Performance Evaluation of Contention-based Channel Access for mmWave Sidelink Communications
No full textOne of the main challenges of future automotive networks is the need to make vehicles aware of their surroundings. Each car will be required to collect data about the environment through dedicated sensors, and share it with its neighbors. Communicating in the millimeter wave spectrum could provide a solution for addressing such requirements. The huge amount of bandwidth available at millimeter wave frequencies, along with an optimized use of the physical resources, could provide massive data rates and low latency capabilities and enable the dissemination of real-time information. In this paper, we focus on platoons of vehicles that share LiDAR pointclouds with their platoon leader, and we use MilliCar, the ns-3 module based on the 3GPP NR V2X specifications, to provide an end-to-end performance evaluation. In particular, we study the trade-offs between using a semi-persistent resource allocation of time slots, with respect to a contention-based approach. By comparing different scheduling alternatives and different clear channel assessment thresholds, we show that coordination among different platoons can mitigate the inter-platoon interference and increase the reliability, whereas a contention-based approach achieves lower transmission delay
Controlling in real-time an ASV-carried ROV for quay wall and ship hull inspection through wireless links in harbor environments
No full textInspection of quay walls and ship hulls is necessary to assess the status of the structure, identifying potential deterioration which may compromise the safety of port and ship operations. The RoboVaaS project aims at reducing the level of human support required to accomplish these tasks by making use of an ASV-carried ROV equipped with multiple cameras and sensors. In this work, we focus on the challenges related to the communication systems needed to ensure the proper information exchange between the ROV, operating underwater, and the shore station. Notably, we propose to rely on the existing port cellular infrastructure and evaluate the end-to-end system performance considering different network configurations (including both 4G and 5G deployments) and system parameters
A Full-Stack Open-Source Framework for Antenna and Beamforming Evaluation in mmWave 5G NR
No full textMillimeter wave (mmWave) communication represents one of the main innovations of the next generation of wireless technologies, allowing users to reach unprecedented data rates. To overcome the high path loss at mmWave frequencies, these systems make use of directional antennas able to focus the transmit power into narrow beams using BeamForming (BF) techniques, thus making the communication directional. This new paradigm opens up a set of challenges for the design of efficient wireless systems, in which antenna and BF components play an important role also at the higher layer of the protocol stack. For this reason, accurate modeling of these components in a full-stack simulation is of primary importance to understand the overall system behavior.This paper proposes a novel framework for the end-to-end simulation of 5G mmWave cellular networks, including a raytracing based channel model and accurate models for antenna arrays and BF schemes. We showcase this framework by evaluating the performance of different antenna and BF configurations considering both link-level and end-to-end metrics and present the obtained results
Simulation of next-generation cellular networks with ns-3: Open challenges and new directions
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Hybrid Beamforming in 5G mmWave Networks: a Full-stack Perspective
Full text linkThis paper studies the cross-layer challenges and performance of Hybrid Beamforming (HBF) and Multi-User Multiple-Input Multiple-Output (MU-MIMO) in 5G millimeter wave (mmWave) cellular networks with full-stack TCP/IP traffic and MAC scheduling. While previous research on HBF and MU-MIMO has focused on link-level analysis of full-buffer transmissions, this work reveals the interplay between HBF techniques and the higher layers of the protocol stack. To this aim, prior work on the full-stack evaluation of mmWave cellular networks has been extended by including the modeling of MU-MIMO and HBF. Our results reveal novel relations between the networking layers and the HBF MU-MIMO performance at the physical layer. Particularly, throughput can be increased in 5G networks by means of Space Division Multiple Access (SDMA). However, in order to achieve such benefits it is necessary to take into account certain trade-offs and the implementation complexity of a full-stack HBF solution
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