Showing papers by "Preben Mogensen published in 2019"
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01 Apr 2019TL;DR: A novel resource allocation method is presented that is latency, control channel, hybrid automatic repeat request (HARQ), and radio channel aware in determining the transmission resources for different users in a fifth generation New Radio networks.
Abstract: We address the problem of resource allocation and packet scheduling for a mixture of ultra- reliable low-latency communication (URLLC) and enhanced mobile broadband (eMBB) traffic in a fifth generation New Radio (5G NR) networks. A novel resource allocation method is presented that is latency, control channel, hybrid automatic repeat request (HARQ), and radio channel aware in determining the transmission resources for different users. This is of high importance for the scheduling of URLLC users in order to minimize their latency, avoid unnecessary costly segmentation of URLLC payloads over multiple transmissions, and benefit from radio channel aware multi-user diversity mechanisms. The performance of the proposed algorithm is evaluated with an advanced 5G NR compliant system level simulator with a high degree of realism. Simulation results show promising gains of up to 98% latency improvement for URLLC traffic and 12% eMBB end-user throughput enhancement as compared to conventional proportional fair scheduling.
48 citations
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18 Jun 2019TL;DR: Results show that the classifier is able to correctly determine occupancy of the authors' offices from the IoT sensor measurements with accuracy up to 94.6% and 91.5% for the binary and multi-class problems.
Abstract: In this paper, we present results on the application of machine learning to the detection of human presence and estimation of the number of occupants in our offices using data from an IoT LoRa-based indoor environment monitoring system at Aalborg University, Denmark. We cast the problem as either binary or multi-class classification and apply a two-layer feed forward neural network to the data. The data used for training, validation and testing of the network comprises of environmental data from the IoT sensors and manual recordings of the door and window states. Results show that the classifier is able to correctly determine occupancy of our offices from the IoT sensor measurements with accuracy up to 94.6% and 91.5% for the binary (presence or absence of persons) and multi-class (no person, one person or two or more persons) problems, respectively. Our analysis also shows that occupancy detection with a network trained either in another room or with single environmental parameter is also possible but with less accuracy.
21 citations
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27 Jun 2019TL;DR: The analysis with 5G new radio assumptions shows that overlaying is mostly beneficial when SIC is employed in medium to high SNR scenarios or, in some cases, with low URLLC load, and the use of separate bands supports higher loads for both services simultaneously.
Abstract: 5G networks should support heterogeneous services with an efficient usage of the radio resources, while meeting the distinct requirements of each service class. We consider the problem of multiplexing enhanced mobile broadband (eMBB) traffic, and grant-free ultra-reliable low-latency communications (URLLC) in uplink. Two multiplexing options are considered; either eMBB and grant-free URLLC are transmitted in separate frequency bands to avoid their mutual interference, or both traffic share the available bandwidth leading to overlaying transmissions. This work presents an approach to evaluate the supported loads for URLLC and eMBB in different operation regimes. Minimum mean square error receivers with and without successive interference cancellation (SIC) are considered in Rayleigh fading channels. The outage probability is derived and the achievable transmission rates are obtained based on that. The analysis with 5G new radio assumptions shows that overlaying is mostly beneficial when SIC is employed in medium to high SNR scenarios or, in some cases, with low URLLC load. Otherwise, the use of separate bands supports higher loads for both services simultaneously. Practical insights based on the approach are discussed.
18 citations
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TL;DR: It is observed that multi-cell reception can provide URLLC capacity gains from 205% to 440% when the BSs are equipped with two receive antennas and 53% to 22% when BSs is equipped with four receive antennas, depending on whether the retransmissions are enabled.
Abstract: The fifth-generation (5G) radio networks will support ultra-reliable low-latency communications (URLLC). In the uplink, the latency can be reduced by removing the time-consuming and error-prone scheduling procedure and, instead, using the grant-free (GF) transmissions. Reaching the strict URLLC reliability requirements with GF transmissions is, however, particularly challenging due to the wireless channel uncertainties and interference from other URLLC devices. As a consequence, the supported URLLC capacity and, hence, the spectral efficiency are typically low. Multi-cell reception, i.e., joint reception and combining by multiple base-stations (BS), is a technique known from long-term evolution (LTE), with the potential to greatly enhance the reliability. This paper proposes the use of multi-cell reception to increase the URLLC spectral efficiency while satisfying the strict requirements using GF transmissions in a 5G new radio (NR) scenario. We evaluate the achievable URLLC capacity for an elaborate multi-cell reception parameter space and multi-cell combining techniques. In addition, we demonstrate that rethinking of the radio resource management (RRM) in the presence of multi-cell reception is needed to unleash the full potential of multi-cell reception in the context of UL GF URLLC. It is observed that multi-cell reception, compared to a single-cell reception, can provide URLLC capacity gains from 205% to 440% when the BSs are equipped with two receive antennas and 53% to 22% when BSs are equipped with four receive antennas, depending on whether the retransmissions are enabled.
15 citations
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01 Apr 2019TL;DR: The results show that the hybrid access strategy managed to reach the performance requirements in most cases and shows potential to enable C2 over cellular networks, without requiring optimization or modifications in the network.
Abstract: In this work, we analyze the end-to-end latency measured in a client-server application that emulates the traffic requirements for the Unmanned Aerial Vehicle (UAV)’s Command and Control (C2) link. The connectivity is provided by two real LTE-A networks to a client attached to a flying UAV. Measurements are performed at 4 different heights: ground level, 15 m, 40 m and 100 m. In single operator scenarios, the reliability measured at the target latency, 50 ms, was between 99.6 % and 97.6 % in downlink, and 91.3% and 99.4% in uplink. These results are below the 99.9 % target reliability defined for UAVs and they show that several consecutive packets can be missed when the radio link connectivity degrades, leading to high (> 1 s) values for the 99.9%-ile of latency. To circumvent this, a dualoperator hybrid access scheme is proposed in this paper. The results show that the hybrid access strategy managed to reach the performance requirements in most cases. The solution shows potential to enable C2 over cellular networks, without requiring optimization or modifications in the network.
14 citations
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27 Jun 2019
TL;DR: This work considers the case of URLLC using grant-free allocation for sporadic transmissions, multiplexed on shared resources with eMBB with high data volume, and the configuration of fractional power control settings upon the coexistence of the different services.
Abstract: 5th generation radio networks should efficiently support services with diverse requirements. For achieving better resource utilization, the sharing of the radio channel between the different services is an attractive solution. While the downlink multiplexing can be well accomplished with dynamic scheduling, efficient multiplexing of enhanced mobile broadband (eMBB) and ultra-reliable low-latency communications (URLLC) in uplink is still an open problem. In particular, we consider the case of URLLC using grant-free allocation for sporadic transmissions, multiplexed on shared resources with eMBB with high data volume. Since the moment in which a grant-free transmission occurs is not known, URLLC and eMBB transmissions overlay. Power control settings are then assessed as a way to manage the performance trade-off between the services. Due to the complexity of 5G new radio, the evaluation is based on advanced system level simulations. Insights regarding the configuration of fractional power control settings upon the coexistence of the different services are presented.
13 citations
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16 Sep 2019TL;DR: It is suggested that repetitions based schemes can, with a careful selection of the sub-band size and uplink power control parameters, achieve comparable URLLC performance with retransmission based schemes when the effect of queuing is disregarded.
Abstract: Ultra-reliable low-latency communications (URLLC) sets high service requirements for the fifth generation (5G) new radio (NR) standard. Grant-free (GF) transmissions is considered a promising technique for reducing the latency in the uplink. To achieve efficient radio resources utilization, sharing of resources is required for sporadic uplink traffic. Repetitions based transmission schemes aims to enhance the reliability of GF transmissions. However, repetitions may also generate excessive interference and cause additional queuing, harming the reliability and latency. In this work, we explore radio resource management (RRM) configurations for repetition based transmission schemes. That includes the number of repetitions, the allocation size per transmission (sub-band), sub-band hopping and uplink power control. Evaluations are conducted in a 5G NR compliant multi-user multi-cell simulation scenario with sporadic uplink GF URLLC transmissions. Our findings suggest that repetitions based schemes can, with a careful selection of the sub-band size and uplink power control parameters, achieve comparable URLLC performance with retransmission based schemes when the effect of queuing is disregarded.
12 citations
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01 Oct 2019TL;DR: The statistical properties of the most important temporal and large-scale propagation characteristics including total received energy, path loss exponent, maximum excess delay (MED), RMS delay spread and root mean square (RMS) delay spread are analyzed based on the measurements.
Abstract: This paper presents the results of wireless channel measurement campaign in the 3 GHz to 8 GHz frequency range. The measurements were performed with focus on the short-range with a transmitter-receiver separation distance less than 9 m in two typical industrial environments: a low clutter density manufacturing space, and a high clutter density one. We analyzed the statistical properties of the most important temporal and large-scale propagation characteristics including total received energy, path loss exponent, maximum excess delay (MED) and root mean square (RMS) delay spread based on the measurements. Statistical models for the RMS delay spread and MED are also presented using the log-normal and Gamma distributions.
12 citations
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01 Mar 2019
TL;DR: In this article, a quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based radio frame code-book is proposed to adaptively update the RFCs in time such that both the average CLI and the user-centric radio latency are minimized.
Abstract: The fifth generation (5G) mobile technology features the ultra-reliable and low-latency communications (URLLC) as a major service class. URLLC applications demand a tight radio latency with extreme link reliability. In 5G dynamic time division duplexing (TDD) systems, URLLC requirements become further challenging to achieve due to the severe and fast-varying cross link interference (CLI) and the switching time of the radio frame configurations (RFCs). In this work, we propose a quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based RFC code-book. The proposed solution adaptively updates the RFCs in time such that both the average CLI and the user-centric radio latency are minimized. Compared to state-of-the-art dynamic TDD studies, the proposed scheme shows a significant improvement in the URLLC outage latency, i.e., ∼ 92% reduction gain, while boosting the cell-edge capacity by ∼ 189% and with a greatly reduced coordination overhead space, limited to B-bit.
11 citations
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07 Nov 2019TL;DR: The path loss analysis confirmed the validity of previously presented modelling frameworks for the behaviour versus height, as well as the characteristics of the increased interference observed when the drone if above rooftop level.
Abstract: Cellular networks based on current LTE Advanced or coming 5G technology, constitute an attractive candidate to provide communication links for drones in low level airspace. This paper extends previous findings on path loss exponent and shadow fading variation for an urban environment, by adding new and more extensive empirical evidence. Specifically, by way of the measurements methodology we study also the spatial correlation of the shadow fading, including the lateral spatial autocorrelation (decorrelation distance) and the cross-correlation in shadowing variability between different heights. Data was obtained with the use of a drone flying at heights up to and above rooftop, using a radio network scanner measuring live LTE signals at 1800 MHz. The path loss analysis confirmed the validity of previously presented modelling frameworks for the behaviour versus height, as well as the characteristics of the increased interference observed when the drone if above rooftop level. As for the spatial correlation of the shadow fading, the results indicate that decorrelation distance does not change appreciably from ground level up to and above rooftop level, and remains in the order of 10 m. The shadow fading variability is generally uncorrelated versus height, although with a trend to be correlated below rooftop level, but not above.
11 citations
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TL;DR: This paper details the general testbed design considerations, along with the specific sounding signal processing implementations, and includes the results from different verification and calibration tests, as well as a real measurement application example.
Abstract: The upcoming fifth-generation wireless technology application areas bring new communication performance requirements, mainly in terms of reliability and latency, but also in terms of radio planning, where the further detailed characterization of the wireless channel is needed. To address these demands, we developed an agile multi-node multi-antenna wireless channel sounding system, using multiple software-defined radio devices. The system consists of 12 testbed nodes which are controlled from a centralized testbed server. Each node features a control host computer and two multi-antenna universal software radio peripheral boards. By managing the transmission and reception of reference signals among all the distributed testbed nodes, the system can measure the channel conditions of all multiple independent radio links. At the same time, the distributed architecture of the testbed allows a large number of spatially distributed locations to be covered with only a few redeployments of the testbed nodes. As a consequence of this, the system favors the collection of a large number of distributed channel samples with limited effort within a short dedicated measurement time. In this paper, we detail the general testbed design considerations, along with the specific sounding signal processing implementations. As further support to the system design, we also include the results from different verification and calibration tests, as well as a real measurement application example.
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TL;DR: A phase calibration method based on transmission of a single out of band tone to overcome the uncertainty introduced by the USRP’s lack of phase alignment is proposed.
Abstract: This paper presents a design of a Software Defined Radio (SDR) multi-antenna testbed able to record live cellular signals from multiple sites. This measurement setup based on Universal Software Radio Peripheral (USRP) boards, is used to record live Long Term Evolution (LTE) signals in sub-6 GHz frequency bands. Due to recording of raw I&Q samples, this fully digital testbed is suitable for variety of research activities spanning channel characterization and beamforming performance evaluation. We propose a phase calibration method based on transmission of a single out of band tone to overcome the uncertainty introduced by the USRP's lack of phase alignment. We demonstrate two use cases where the proposed testbed can be used and we validate its performance during two measurement campaigns with self-generated and real cellular signals.
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01 Apr 2019
TL;DR: Results show that receive beamforming can outperform MRC in low- interfered scenarios with high Line of Sight (LoS) probability, like highways or rural areas, while ensuring comparable performance even in dense urban scenarios where LoS communication cannot be guaranteed.
Abstract: Cellular Vehicle to Everything (C-V2X) communications with its safety and infotainment services will require a high performance receivers to cope with challenging throughput, latency and reliability requirements. With increasing levels of interference due to cell densification and introduction of the roadside units, single antenna receivers may not be able to provide the required quality of service. In this work we experimentally study the performance of multi antenna receivers based on more than 150 km of data recorded during experiments using a customized software defined radio testbed. The performance of sixteen antennas Maximum Ratio Combiner (MRC) is compared with the receive beamforming technique for the live cellular signals in the 1.8 GHz band. This study is followed by an analysis of the impact of interference and measurement environment on the receiver’s performance. The results show that receive beamforming can outperform MRC in low- interfered scenarios with high Line of Sight (LoS) probability, like highways or rural areas, while ensuring comparable performance even in dense urban scenarios where LoS communication cannot be guaranteed.
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07 Nov 2019TL;DR: The main goal of this paper is to study the feasibility of ray tracing models to accurately predict shadow fading variations at different heights, so that the shadow fading correlation distances for the UAV channel can be found in both vertical and horizontal directions, without the need of performing extensive field measurement campaigns.
Abstract: Although the use of cellular networks to serve drones has been investigated in several recent works, the path loss or shadowing variation is still relatively unexplored. The variation and its dynamic behaviour is of importance in characterizing the reliability of the drone communication link, but difficult to assess by experimental means on a large scale. The main goal of this paper is to study the feasibility of ray tracing models to accurately predict shadow fading variations at different heights, so that the shadow fading correlation distances for the UAV channel can be found in both vertical and horizontal directions, without the need of performing extensive field measurement campaigns. For that, predictions obtained through a ray tracing tool are compared to field measurements in an urban scenario. Our results show that with accurate 3D maps, the tool is useful for predicting the dynamics of the UAV propagation channel, and therefore can be used partly as a substitute for field measurements.
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27 Jun 2019
TL;DR: Compared to the state-of-the-art schedulers from industry and academia, proposed scheduler framework shows significant scheduling flexibility in terms of the overall ergodic capacity and URLLC latency performance.
Abstract: This paper introduces a preemptive rank offloading scheduling framework for joint ultra-reliable low-latency communications (URLLC) and enhanced mobile broadband (eMBB) traffic in 5G new radio (NR). Proposed scheduler dynamically adapts the overall system optimization among the network-centric ergodic capacity and the user-centric URLLC one-way latency, based on the instantaneous traffic and radio resources availability. The spatial degrees of freedom, offered by the transmit antenna array, are fully exploited to maximize the overall spectral efficiency. However, when URLLC traffic buffering is foreseen, proposed scheduler immediately enforces scheduling pending URLLC payloads through preemption-aware subspace projection. Compared to the state-of-the-art schedulers from industry and academia, proposed scheduler framework shows significant scheduling flexibility in terms of the overall ergodic capacity and URLLC latency performance. The presented results therefore offer valuable insights of how to most efficiently multiplex joint URLLC-eMBB traffic over the 5G NR spectrum.
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01 Sep 2019TL;DR: Interference measurements covering the UWB spectrum from 3GHz to 11GHz conducted at two locations on the campus of Aalborg University, Denmark indicate that signal activity vary significantly across the spectrum with the 5GHz - 6GHz and 9GHz - 10GHz sub-bands having the strongest power levels in the indoor and outdoor measurements, respectively.
Abstract: Ultra-wide band (UWB) radio systems are expected to operate in co-existence with a myriad of other systems over a large unlicensed bandwidth. Thus, UWB devices need to incorporate efficient inter-system interference mitigation mechanisms. In this paper, we present interference measurements covering the UWB spectrum from 3GHz to 11GHz conducted at two locations (indoor and outdoor) on the campus of Aalborg University, Denmark. We analysed the measurements in terms of occurrence probability, interference power distribution and inter-arrival time statistics. The goal is to understand the characteristics of signals emanating from systems operating on this ultra-wide bandwidth as a basis for the development of models and methods for interference characterization and mitigation. Results indicate that signal activity vary significantly across the spectrum with the 5GHz - 6GHz and 9GHz - 10GHz sub-bands having the strongest power levels in the indoor and outdoor measurements, respectively. Statistical analysis results further show significant variation of the power distribution, occurrence probability and inter- arrival time statistics for the various signals detected in the measurements. Results also show that time between interference occurrence is exponentially distributed for most of the sources.
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27 Jun 2019
TL;DR: Multi-connectivity is explored as a solution for assuring high reliability in industrial scenarios, but at the cost of a reduced throughput in the mobile broadband services on the same network.
Abstract: In the last years, wireless communications in industrial scenarios are becoming an increasingly important market. Some of these communications have tight reliability requirements, but harsh propagation conditions in industrial scenarios represent a major challenge. In this paper, multi-connectivity is explored as a solution for assuring high reliability in industrial scenarios. Several multi-connectivity techniques are compared, using real channel measurements from two factories. Multiconnectivity comes at the cost of a reduced throughput in the mobile broadband services on the same network. In this paper, this impact is quantified to assess for the cost of implementing multi-connectivity.
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15 Apr 2019TL;DR: Network capacity results show that, deploying a sparse network with reservation of 1.4 MHz is sufficient for most cases according to current demands, and the increase in demand can be followed by a continuous deployment of sites and an increase in the bandwidth up to 5 MHz.
Abstract: In this paper, the usage of dedicated portions of cellular spectrum to provide the high-reliable Command and Control (C2) link for Unmanned Aerial Vehicles (UAVs) is evaluated. Simulations are performed using data settings of a real operating Long-Term Evolution (LTE) network in Denmark, in order to assess the reliability of the C2 link. Up to date databases of drone registrations and market projections are used to infer the drone densities and estimate the future traffic demand. Based on these estimations, network capacity results show that, deploying a sparse network with reservation of 1.4 MHz is sufficient for most cases according to current demands. In the next 20 years, the increase in demand can be followed by a continuous deployment of sites and an increase in the bandwidth up to 5 MHz. The paper also presents a discussion about which solutions can be used to further boost network capacity, and help to achieve high reliability even for the most stringent traffic demand cases.
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01 Mar 2019TL;DR: In this paper, the authors evaluate the variation of mean Angle of Arrival (AoA) and Angular Spread (AS) with height based on the experimental measurements using live Long Term Evolution (LTE) networks.
Abstract: Spatial channel characterization of a cellular Unmanned Aerial Vehicle (UAV) Air-to-Ground (AG) communication link is a vital step to understand the potential of beam-forming in the take-off zone, when a UAV flies in the vicinity of other objects. In this paper, we evaluate the variation of mean Angle of Arrival (AoA) and Angular Spread (AS) with height based on the experimental measurements using live Long Term Evolution (LTE) networks. The LTE signals are recorded at different heights from a ground level up to 40 m in rural and urban environments. Space-Alternating Generalized Expectation-Maximization (SAGE) algorithm is used for the estimation of the angular parameters. Results show similar mean AoA at different heights, with less than 55 degrees deviation in urban environment and no more than 20 degrees change in rural scenarios. Observed AS is reduced to less than 30 degrees at increasing heights as the Line of Sight (LoS) propagation becomes dominant. However the comparison between urban and rural environments clearly indicates the presence of relevant multipath components in the urban scenarios even 20 m above the rooftops level.
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01 Dec 2019TL;DR: It has been found that the UL throughput does not improve with the increase of antenna gain probably due to the UL Power Control mechanism used in LTE.
Abstract: Cellular networks will be one of the main pillars in the development of future vehicular communications. However, downlink (DL) and uplink (UL) channels must be improved to cope with the required reliability and high throughput of the coming vehicular use cases. Vehicle side solutions which benefit from the high antenna gains could improve the performance of the UL channel whose coverage is limited by UL transmit power. In this paper we experimentally evaluate the performance of a directional antennas switching system based on live Long Term Evolution (LTE) measurements. A total of more than 150 km have been driven comprising different radio propagation scenarios. The results show considerable improvements of Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ), together with a reduction of handovers specially in scenarios with high Line-Of-Sight probability. Additionally, it has been found that the UL throughput does not improve with the increase of antenna gain probably due to the UL Power Control mechanism used in LTE.
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21 Oct 2019TL;DR: Analysis of dynamic point selection and frequency-selective multi-user scheduling to improve ultra-reliable low-latency communication (URLLC) for the fifth generation New Radio (5G NR) systems indicate that for DPS, user-specific clustering with 3-dB power range achieves the major improvement of URLLC latency.
Abstract: This paper studies dynamic point selection (DPS) and frequency-selective multi-user scheduling to improve ultra-reliable low-latency communication (URLLC) for the fifth generation New Radio (5G NR) systems. DPS is a special type of multi-channel access scheme enhances the network performance by enabling dynamic transmission point selection on a fast time-scale. The achieved gain from frequency-selective URLLC scheduling is further studied by investigating a low-complexity resource allocation algorithm. Extensive 5G NR system-level simulation results show that DPS achieves 30% improvement of URLLC latency. Our analyses also indicate that for DPS, user-specific clustering with 3-dB power range achieves the major improvement of URLLC latency.
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17 Jun 2019TL;DR: This paper presents the vision and initial design of a wireless manufacturing execution system (MES) solution, which will be soon integrated in the fully-automated small production line in the Smart Production Lab at Aalborg University.
Abstract: This paper presents our vision and initial design of a wireless manufacturing execution system (MES) solution, which will be soon integrated in the fully-automated small production line in the Smart Production Lab at Aalborg University. The replacement of the current Ethernet-based control system with our wireless solution, will allow to remove all communication wires between the different stations of the production line and thus, enabling a faster re-configuration of the production facilities. The proposed solution also sets the base for the future integration of new industrial use cases requiring full mobility support.
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01 Sep 2019TL;DR: Investigating how the topographic changes over the course of 10 years of continuous mining affect the propagation conditions, and impacts the performance associated with different deployment strategies for wireless networks in a large open-pit mining complex in Brazil shows that heterogeneous deployments can be exploited to continuously guarantee coverage.
Abstract: The mining industry is on a transition towards unmanned operations. This implies a step change in wireless infrastructure expansion to support autonomous and teleoperated machinery. This paper investigates how the topographic changes over the course of 10 years of continuous mining affect the propagation conditions, and impacts the performance associated with different deployment strategies for wireless networks in a large open-pit mining complex in Brazil. Through a series of system-level simulations, using detailed terrain models, realistic traffic volumes and a dedicated propagation model, we compare the ability of different deployment strategies, and network features, to meet given performance targets with existing technology. The results show that heterogeneous deployments can be exploited to continuously guarantee coverage in this ever- changing topography, while interference mitigation techniques, such as enhanced inter-cell interference coordination (eICIC) and beamforming, can be used to reduce the system outage without need to increase the spectrum.
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01 Sep 2019
TL;DR: The results show that the downlink-based beam sweep leads to higher Signal to Interference and Noise Ratio (SINR) than beamforming based on the estimated AoA, and the feasibility of signal tracking techniques exploiting the location of the vehicle and the BS are investigated to alleviate the need for continuous direction acquisition.
Abstract: This work evaluates the concept of uplink beamforming for vehicular communications in the sub-6 GHz frequency bands to improve throughput, latency and coverage of the vehicle to Base Station (BS) link. The data recorded in the experimental measurements using live cellular signals are used to study the performance of two direction acquisition methods: the Angle of Arrival (AoA) estimation and downlink-based beam sweep. Next, the feasibility of signal tracking techniques exploiting the location of the vehicle and the BS are investigated to alleviate the need for continuous direction acquisition. The results show that the downlink-based beam sweep leads to higher Signal to Interference and Noise Ratio (SINR) than beamforming based on the estimated AoA. Evaluated tracking techniques are shown to be capable of correctly estimating the beamforming angle for distances in order of hundreds of meters when BS's location is known to the vehicle.
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01 Sep 2019
TL;DR: This work summarizes and compares the results collected in two distinct measurement campaigns, with the predictions of a dedicated path loss model (Vale Model) previously derived from measurements in surface mines, and shows that the Vale model provides a good fit for path loss prediction in open-pit mines, with RMSE values in the order of 7 dB.
Abstract: As in other vertical markets, wireless communications are expected to play a fundamental role in the digitalization of the mining industry. Akin to most industrial applications, careful and scenario specific understanding of the radio propagation conditions is key to plan and deploy a reliable wireless network. However, surface mining presents an additional challenge when compared to other industrial scenarios: inherent large-scale topographic variability. Therefore, it is necessary to validate if the radio propagation models remain accurate over large topographic change. In this work, we summarize and compare the results collected in two distinct measurement campaigns, with the predictions of a dedicated path loss model (Vale Model) previously derived from measurements in surface mines. The second measurement campaign is performed by means of an automated site survey, that takes advantage of operational wireless systems and mining equipment to collect data samples. The results show that even with different transmit frequencies, topographic variation, test equipment, and measurement methods (dedicated versus automated site surveys), the Vale model provides a good fit for path loss prediction in open-pit mines, with RMSE values in the order of 7 dB. Besides, this is the first time a radio propagation model has been validated over large topographic changes in a surface mining scenario.
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TL;DR: A quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based RFC code-book is proposed to improve the URLLC outage latency and boost the cell-edge capacity with a greatly reduced coordination overhead space.
Abstract: The fifth generation (5G) mobile technology features the ultra-reliable and low-latency communications (URLLC) as a major service class. URLLC applications demand a tight radio latency with extreme link reliability. In 5G dynamic time division duplexing (TDD) systems, URLLC requirements become further challenging to achieve due to the severe and fast-varying cross link interference (CLI) and the switching time of the radio frame configurations (RFCs). In this work, we propose a quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based RFC code-book. The proposed solution adaptively updates the RFCs in time such that both the average CLI and the user-centric radio latency are minimized. Compared to state-of-the-art dynamic TDD studies, the proposed scheme shows a significant improvement in the URLLC outage latency, i.e., 92% reduction gain, while boosting the cell-edge capacity by 189% and with a greatly reduced coordination overhead space, limited to B-bit.