2,987 research outputs found
In-situ measurement methodology for the assessment of 5G NR massive MIMO base station exposure at sub-6 GHz frequencies
As the roll-out of the fifth generation (5G) of mobile telecommunications is well underway, standardized methods to assess the human exposure to radiofrequency electromagnetic fields from 5G base station radios are needed in addition to existing numerical models and preliminary measurement studies. Challenges following the introduction of 5G New Radio (NR) include the utilization of new spectrum bands and the widespread use of technological advances such as Massive MIMO (Multiple-Input Multiple-Output) and beamforming. We propose a comprehensive and ready-to-use exposure assessment methodology for use with common spectrum analyzer equipment to measure or calculate in-situ the time-averaged instantaneous exposure and the theoretical maximum exposure from 5G NR base stations. Besides providing the correct method and equipment settings to capture the instantaneous exposure, the procedure also comprises a number of steps that involve the identification of the Synchronization Signal Block, which is the only 5G NR component that is transmitted periodically and at constant power, the assessment of the power density carried by its resources, and the subsequent extrapolation to the theoretical maximum exposure level. The procedure was validated on site for a 5G NR base station operating at 3.5 GHz, but it should be generally applicable to any 5G NR signal, i.e., as is for any sub-6 GHz signal and after adjustment of the proposed measurement settings for signals in the millimeter-wave range
How Does 5G NR V2X Mode 2 Handle Aperiodic Packets and Variable Packet Sizes?
—5G NR V2X complements LTE V2X to support
advanced V2X services for connected and automated driving.
5G NR V2X introduces novel features at the MAC layer that are
designed to cope with potential packet collisions, and that could
help address the LTE V2X MAC inefficiencies observed under
aperiodic traffic of variable size. This is the case of the reevaluation mechanism that is a mandatory MAC feature of 5G
NR V2X, and that seeks avoiding possible packet collisions
detected before a vehicle transmits in selected resources.
Evaluations conducted to date of 5G NR V2X do not consider
the re-evaluation mechanism, and have focused on traffic
patterns that do not fully account for the traffic variability of
advanced V2X services. This paper extends the current state of
the art with the first evaluation of a fully standard compliant 5G
NR V2X implementation under the traffic patterns
recommended by 3GPP for advanced V2X services. Our study
shows that 5G NR V2X Mode 2 still faces MAC challenges when
using semi-persistent scheduling (SPS) to efficiently support
aperiodic traffic of variable size
Radio Resource Management for New Application Scenarios in 5G: Optimization and Deep Learning
The fifth-generation (5G) New Radio (NR) systems are expected to support a wide range of emerging applications with diverse Quality-of-Service (QoS) requirements. New application scenarios in 5G NR include enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable low-latency communications (URLLC). New wireless architectures, such as full-dimension (FD) massive multiple-input multiple-output (MIMO) and mobile edge computing (MEC) system, and new coding scheme, such as short block-length channel coding, are envisioned as enablers of QoS requirements for 5G NR applications. Resource management in these new wireless architectures is crucial in guaranteeing the QoS requirements of 5G NR systems. The traditional optimization problems, such as subcarriers and user association, are usually non-convex or Non-deterministic Polynomial-time (NP)-hard. It is time-consuming and computing-expensive to find the optimal solution, especially in a large-scale network. To solve these problems, one approach is to design a low-complexity algorithm with near optimal performance. In some cases, the low complexity algorithms are hard to obtain, deep learning can be used as an accurate approximator that maps environment parameters, such as the channel state information and traffic state, to the optimal solutions. In this thesis, we design low-complexity optimization algorithms, and deep learning frameworks in different architectures of 5G NR to resolve optimization problems subject to QoS requirements. First, we propose a low-complexity algorithm for a joint cooperative beamforming and user association problem for eMBB in 5G NR to maximize the network capacity. Next, we propose a deep learning (DL) framework to optimize user association, resource allocation, and offloading probabilities for delay-tolerant services and URLLC in 5G NR. Finally, we address the issue of time-varying traffic and network conditions on resource management in 5G NR
Random Linear Network Coding for 5G Mobile Video Delivery
An exponential increase in mobile video delivery will continue with the
demand for higher resolution, multi-view and large-scale multicast video
services. Novel fifth generation (5G) 3GPP New Radio (NR) standard will bring a
number of new opportunities for optimizing video delivery across both 5G core
and radio access networks. One of the promising approaches for video quality
adaptation, throughput enhancement and erasure protection is the use of
packet-level random linear network coding (RLNC). In this review paper, we
discuss the integration of RLNC into the 5G NR standard, building upon the
ideas and opportunities identified in 4G LTE. We explicitly identify and
discuss in detail novel 5G NR features that provide support for RLNC-based
video delivery in 5G, thus pointing out to the promising avenues for future
research.Comment: Invited paper for Special Issue "Network and Rateless Coding for
Video Streaming" - MDPI Informatio
ML-Enabled Outdoor User Positioning in 5G NR Systems via Uplink SRS Channel Estimates
Cellular user positioning is a promising service provided by Fifth Generation
New Radio (5G NR) networks. Besides, Machine Learning (ML) techniques are
foreseen to become an integrated part of 5G NR systems improving radio
performance and reducing complexity. In this paper, we investigate ML
techniques for positioning using 5G NR fingerprints consisting of uplink
channel estimates from the physical layer channel. We show that it is possible
to use Sounding Reference Signals (SRS) channel fingerprints to provide
sufficient data to infer user position. Furthermore, we show that small
fully-connected moderately Deep Neural Networks, even when applied to very
sparse SRS data, can achieve successful outdoor user positioning with
meter-level accuracy in a commercial 5G environment.Comment: 6 pages, 8 figures, Accepted to be published in IEEE International
Conference on Communications 2023, Rome, Ital
- …