The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sven Parand - One of the best experts on this subject based on the ideXlab platform.
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dynamic Radio Frame configuration by exploiting uplink control channel for urllc
Wireless Communications and Networking Conference, 2019Co-Authors: Navuday Sharma, Muhammad Mahtab Alam, Yannick Le Moullec, Hassan Malik, Mehdi Bennis, Sven ParandAbstract:uRLLC (ultra-Reliable Low Latency Communications) requires a new paradigm in 5G cellular networks to satisfy extreme latency and reliability thresholds. Further, such constraints have a wide range due to different use case scenarios. Consequently, how to configure suitable Radio Frame structure that matches to the latency and reliability requirements of the given use-case is an open question. This article addresses the above-mentioned issue and provides a preliminary investigation and a feasible solution by exploiting antenna port selection index (APSI) calculated using fuzzy logic algorithm, which is further communicated through physical uplink control channel. Closed-form expressions of outage probability for the number of users, under given latency and reliability constraints have been provided with the mathematical proof and the results were simulated based on the prior availability of APSI. It is shown that outage probability improves up to 30% in case of dynamic Radio Frame configuration.
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WCNC Workshops - Dynamic Radio Frame Configuration by Exploiting Uplink Control Channel for URLLC
2019 IEEE Wireless Communications and Networking Conference Workshop (WCNCW), 2019Co-Authors: Navuday Sharma, Muhammad Mahtab Alam, Yannick Le Moullec, Hassan Malik, Mehdi Bennis, Sven ParandAbstract:uRLLC (ultra-Reliable Low Latency Communications) requires a new paradigm in 5G cellular networks to satisfy extreme latency and reliability thresholds. Further, such constraints have a wide range due to different use case scenarios. Consequently, how to configure suitable Radio Frame structure that matches to the latency and reliability requirements of the given use-case is an open question. This article addresses the above-mentioned issue and provides a preliminary investigation and a feasible solution by exploiting antenna port selection index (APSI) calculated using fuzzy logic algorithm, which is further communicated through physical uplink control channel. Closed-form expressions of outage probability for the number of users, under given latency and reliability constraints have been provided with the mathematical proof and the results were simulated based on the prior availability of APSI. It is shown that outage probability improves up to 30% in case of dynamic Radio Frame configuration.
Rahim Tafazolli - One of the best experts on this subject based on the ideXlab platform.
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Enabling Massive IoT in 5G and beyond Systems: PHY Radio Frame Design Considerations
IEEE Access, 2016Co-Authors: Ayesha Ijaz, Maxime Grau, Atta Ul Quddus, Muhammad Ali Imran, Serdar Vural, Chuan Heng Foh, Abdelrahim Mohamed, Lei Zhang, Rahim TafazolliAbstract:The parameters of physical layer Radio Frame for 5th generation (5G) mobile cellular systems are expected to be flexibly configured to cope with diverse requirements of different scenarios and services. This paper presents a Frame structure and design, which is specifically targeting Internet of Things (IoT) provision in 5G wireless communication systems. We design a suitable Radio numerology to support the typical characteristics, that is, massive connection density and small and bursty packet transmissions with the constraint of low-cost and low complexity operation of IoT devices. We also elaborate on the design of parameters for random access channel enabling massive connection requests by IoT devices to support the required connection density. The proposed design is validated by link level simulation results to show that the proposed numerology can cope with transceiver imperfections and channel impairments. Furthermore, the results are also presented to show the impact of different values of guard band on system performance using different subcarrier spacing sizes for data and random access channels, which show the effectiveness of the selected waveform and guard bandwidth. Finally, we present system-level simulation results that validate the proposed design under realistic cell deployments and inter-cell interference conditions. INDEX TERMS 5G, Frame structure, Internet of Things, random access channel.
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Enabling Massive IoT in 5G and Beyond Systems: PHY Radio Frame Design Considerations
IEEE Access, 2016Co-Authors: Ayesha Ijaz, Maxime Grau, Atta Ul Quddus, Muhammad Ali Imran, Serdar Vural, Abdelrahim Mohamed, Lei Zhang, Rahim TafazolliAbstract:The parameters of physical layer Radio Frame for 5th generation (5G) mobile cellular systems are expected to be flexibly configured to cope with diverse requirements of different scenarios and services. This paper presents a Frame structure and design, which is specifically targeting Internet of Things (IoT) provision in 5G wireless communication systems. We design a suitable Radio numerology to support the typical characteristics, that is, massive connection density and small and bursty packet transmissions with the constraint of low-cost and low complexity operation of IoT devices. We also elaborate on the design of parameters for random access channel enabling massive connection requests by IoT devices to support the required connection density. The proposed design is validated by link level simulation results to show that the proposed numerology can cope with transceiver imperfections and channel impairments. Furthermore, the results are also presented to show the impact of different values of guard band on system performance using different subcarrier spacing sizes for data and random access channels, which show the effectiveness of the selected waveform and guard bandwidth. Finally, we present system-level simulation results that validate the proposed design under realistic cell deployments and inter-cell interference conditions.
Klaus I. Pedersen - One of the best experts on this subject based on the ideXlab platform.
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semi static Radio Frame configuration for urllc deployments in 5g macro tdd networks
arXiv: Signal Processing, 2020Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben MogensenAbstract:Dynamic time division duplexing (TDD) is one of the major novelties of the 5G new Radio standard. It notably improves the network resource utilization with sporadic directional packet arrivals. Although, the feasibility of the ultra-reliable and low-latency communications (URLLC) within such deployments is critically challenged, mainly due to the cross-link interference (CLI). In this work, we propose a semi-static and computationally-efficient TDD Radio Frame adaptation algorithm for 5G macro deployments. Particularly, we first identify the quasi-static variance of the cross-cell traffic buffering performance, with various CLI co-existence conditions. Accordingly, a common Radio Frame pattern is dynamically estimated based on the filtered multi-cell traffic statistics. Our system-level simulation results show that the proposed solution achieves a highly improved URLLC outage performance, i.e., offering 40% reduction gain of the achievable URLLC outage latency compared to perfect static-TDD, and approaching the optimal interference-free flexible-TDD case; though, with a significantly lower control overhead size.
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VTC Spring - Inter-Cell Radio Frame Coordination Scheme Based on Sliding Codebook for 5G TDD Systems
2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019Co-Authors: Ali A. Esswie, Klaus I. PedersenAbstract:The fifth generation (5G) of the wireless communication networks supports wide diversity of service classes, leading to a highly dynamic uplink (UL) and downlink (DL) traffic asymmetry. Thus, dynamic time division duplexing (TDD) technology has become of a significant importance, due to its Radio Frame flexibility. However, fully dynamic TDD systems suffer from potentially severe inter-cell cross link interference (CLI). In this paper, we propose a novel inter-cell Radio Frame coordination (RFC) scheme based on sliding codebook for fully dynamic TDD 5G networks. Proposed coordination scheme simultaneously addresses two optimization objectives of minimizing the average CLI while reliably maximizing the achievable DL/UL capacity, by virtually extending the RFC degrees of freedom through a sliding phase-offset RFC codebook design. Compared to the state-of-the-art TDD studies, the proposed scheme shows significantly improved ergodic capacity, i.e., at least 140% gain under both the TCP and UDP protocols, and with much less signaling overhead, limited to B-bit. The paper offers valuable insights about how to most efficiently pre-mitigate potential CLI in Macro TDD systems.
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Quasi-Dynamic Frame Coordination for Ultra-Reliability and Low-Latency in 5G TDD Systems
2019 IEEE International Conference on Communications Workshops (ICC Workshops), 2019Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben Elgaard MogensenAbstract: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 fastvarying 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.
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ICC Workshops - Quasi-Dynamic Frame Coordination for Ultra-Reliability and Low-Latency in 5G TDD Systems
2019 IEEE International Conference on Communications Workshops (ICC Workshops), 2019Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben MogensenAbstract: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.
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Inter-Cell Radio Frame Coordination Scheme Based on Sliding Codebook for 5G TDD Systems
2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019Co-Authors: Ali A. Esswie, Klaus I. PedersenAbstract:The fifth generation (5G) of the wireless communication networks supports wide diversity of service classes, leading to a highly dynamic uplink (UL) and downlink (DL) traffic asymmetry. Thus, dynamic time division duplexing (TDD) technology has become of a significant importance, due to its Radio Frame flexibility. However, fully dynamic TDD systems suffer from potentially severe inter-cell cross link interference (CLI). In this paper, we propose a novel inter-cell Radio Frame coordination (RFC) scheme based on sliding codebook for fully dynamic TDD 5G networks. Proposed coordination scheme simultaneously addresses two optimization objectives of minimizing the average CLI while reliably maximizing the achievable DL/UL capacity, by virtually extending the RFC degrees of freedom through a sliding phase-offset RFC codebook design. Compared to the state-of-the-art TDD studies, the proposed scheme shows significantly improved ergodic capacity, i.e., at least ~ 140% gain under both the TCP and UDP protocols, and with much less signaling overhead, limited to B-bit. The paper offers valuable insights about how to most efficiently pre-mitigate potential CLI in Macro TDD systems.
G Bourda - One of the best experts on this subject based on the ideXlab platform.
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Celestial Reference Systems: Stability and Alignment
2020Co-Authors: G BourdaAbstract:n this paper, we come back on the history of celestial reference systems, until the Gaia era, and we lay the foundations of this research area. Gaia should revolutionize this domain by creating the first extragalactic celestial reference Frame directly at optical bands, on the basis of more than 10000 QSOs (Quasi Stellar Objects). In parallel, the Radio Frame obtained with the VLBI (Very Long Baseline Interferometry) technique has been the IAU (International Astronomical Union) fundamental celestial reference Frame for several decades. The alignment between these two Frames will be important in the future, not only for guaranteeing a proper transition if the fundamental reference Frame is moved from the Radio to the optical domain, but also for registering the Radio and optical images of any celestial target with the highest accuracy. This should be of high astrophysical interest, for example to probe properly the physics of active galactic nuclei (AGN) hence placing constraints on the overall AGN geometry. We will present the studies investigated so far (in the Radio but also optical domains) in order to prepare the celestial reference Frame for the Gaia era.
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vlbi observations of optically bright extragalactic Radio sources for the alignment of the Radio Frame with the future gaia Frame ii imaging candidate sources
Astronomy and Astrophysics, 2011Co-Authors: G Bourda, P Charlot, R W Porcas, A Collioud, S T GarringtonAbstract:Context. The European space astrometry mission Gaia, to be launched by 2012, will construct a dense optical QSO-based celestial reference Frame which will need to be linked to the International Celestial Reference Frame (ICRF; the IAU fundamental Frame), with the highest accuracy. However, it has been found that only 10% of the ICRF sources (70 sources) are suitable to establish this link. The remaining sources are not useful either because they are not bright enough at optical wavelengths or because they have significant extended Radio emission which precludes reaching the highest astrometric accuracy. Aims: In order to improve the accuracy of this alignment, we have developed a program of VLBI observations based on three steps to detect, image and measure astrometric positions of weak extragalactic Radio sources, with bright optical counterparts, from a sample of 447 candidate sources. Methods: The experiments devoted to VLBI detection, carried out with the European VLBI Network (EVN) in June and October 2007, were very successful, with 398 sources detected at both S- and X-bands. From these, 105 sources were observed in March 2008 with a global VLBI array (EVN and VLBA; Very Long Baseline Array) for imaging their VLBI structures. Results: All sources were successfully imaged in both bands and about 50% (47 sources) were found to be point-like on VLBI scales. These images are available at http://www.obs.u-bordeaux1.fr/BVID/GC030/. VLBI positions of these sources will be measured accurately in future astrometric experiments. Full Table 3 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A102
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vlbi observations of optically bright extragalactic Radio sources for the alignment of the Radio Frame with the future gaia Frame i source detection
Astronomy and Astrophysics, 2010Co-Authors: G Bourda, P Charlot, R W Porcas, S T GarringtonAbstract:Context. The European space astrometry mission Gaia will construct a dense optical QSO-based celestial reference Frame. For consistency between optical and Radio positions, it will be important to align the Gaia and VLBI Frames with the highest possible accuracy. It has been found that only 70 (10%) of the sources from the International Celestial Reference Frame (ICRF) are suitable for establishing this link, either because they are not bright enough at optical wavelengths or because they have significant extended Radio emission which precludes reaching the highest astrometric accuracy. Aims. In order to improve the situation, we have initiated a VLBI survey dedicated to finding additional suitable Radio sources for aligning the two Frames. Methods. The sample consists of 447 optically-bright (magnitude ≤18) extragalactic Radio sources, typically 20 times weaker than the ICRF sources, which have been selected by cross-correlating an optical quasar catalog with the NRAO VLA Sky Survey (NVSS). Results. This paper presents the observing strategy to detect, image, and measure accurate Radio positions for these sources. It also provides results on the VLBI detectability of the sources, as derived from initial observations with the European VLBI Network in June and October 2007. Based on these observations, a high detection rate of 89% is found, which is promising for the continuation of this project. This high VLBI detection rate for sources from the NVSS catalog is probably due to the selection process, suggesting that optically-bright quasars have compact Radio structures.
Ali A. Esswie - One of the best experts on this subject based on the ideXlab platform.
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semi static Radio Frame configuration for urllc deployments in 5g macro tdd networks
arXiv: Signal Processing, 2020Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben MogensenAbstract:Dynamic time division duplexing (TDD) is one of the major novelties of the 5G new Radio standard. It notably improves the network resource utilization with sporadic directional packet arrivals. Although, the feasibility of the ultra-reliable and low-latency communications (URLLC) within such deployments is critically challenged, mainly due to the cross-link interference (CLI). In this work, we propose a semi-static and computationally-efficient TDD Radio Frame adaptation algorithm for 5G macro deployments. Particularly, we first identify the quasi-static variance of the cross-cell traffic buffering performance, with various CLI co-existence conditions. Accordingly, a common Radio Frame pattern is dynamically estimated based on the filtered multi-cell traffic statistics. Our system-level simulation results show that the proposed solution achieves a highly improved URLLC outage performance, i.e., offering 40% reduction gain of the achievable URLLC outage latency compared to perfect static-TDD, and approaching the optimal interference-free flexible-TDD case; though, with a significantly lower control overhead size.
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VTC Spring - Inter-Cell Radio Frame Coordination Scheme Based on Sliding Codebook for 5G TDD Systems
2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019Co-Authors: Ali A. Esswie, Klaus I. PedersenAbstract:The fifth generation (5G) of the wireless communication networks supports wide diversity of service classes, leading to a highly dynamic uplink (UL) and downlink (DL) traffic asymmetry. Thus, dynamic time division duplexing (TDD) technology has become of a significant importance, due to its Radio Frame flexibility. However, fully dynamic TDD systems suffer from potentially severe inter-cell cross link interference (CLI). In this paper, we propose a novel inter-cell Radio Frame coordination (RFC) scheme based on sliding codebook for fully dynamic TDD 5G networks. Proposed coordination scheme simultaneously addresses two optimization objectives of minimizing the average CLI while reliably maximizing the achievable DL/UL capacity, by virtually extending the RFC degrees of freedom through a sliding phase-offset RFC codebook design. Compared to the state-of-the-art TDD studies, the proposed scheme shows significantly improved ergodic capacity, i.e., at least 140% gain under both the TCP and UDP protocols, and with much less signaling overhead, limited to B-bit. The paper offers valuable insights about how to most efficiently pre-mitigate potential CLI in Macro TDD systems.
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Quasi-Dynamic Frame Coordination for Ultra-Reliability and Low-Latency in 5G TDD Systems
2019 IEEE International Conference on Communications Workshops (ICC Workshops), 2019Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben Elgaard MogensenAbstract: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 fastvarying 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.
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ICC Workshops - Quasi-Dynamic Frame Coordination for Ultra-Reliability and Low-Latency in 5G TDD Systems
2019 IEEE International Conference on Communications Workshops (ICC Workshops), 2019Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben MogensenAbstract: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.
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Inter-Cell Radio Frame Coordination Scheme Based on Sliding Codebook for 5G TDD Systems
2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019Co-Authors: Ali A. Esswie, Klaus I. PedersenAbstract:The fifth generation (5G) of the wireless communication networks supports wide diversity of service classes, leading to a highly dynamic uplink (UL) and downlink (DL) traffic asymmetry. Thus, dynamic time division duplexing (TDD) technology has become of a significant importance, due to its Radio Frame flexibility. However, fully dynamic TDD systems suffer from potentially severe inter-cell cross link interference (CLI). In this paper, we propose a novel inter-cell Radio Frame coordination (RFC) scheme based on sliding codebook for fully dynamic TDD 5G networks. Proposed coordination scheme simultaneously addresses two optimization objectives of minimizing the average CLI while reliably maximizing the achievable DL/UL capacity, by virtually extending the RFC degrees of freedom through a sliding phase-offset RFC codebook design. Compared to the state-of-the-art TDD studies, the proposed scheme shows significantly improved ergodic capacity, i.e., at least ~ 140% gain under both the TCP and UDP protocols, and with much less signaling overhead, limited to B-bit. The paper offers valuable insights about how to most efficiently pre-mitigate potential CLI in Macro TDD systems.
