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  • 1.
    Azari, Amin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Energy-efficient scheduling and grouping for machine-type communications over cellular networks2016Inngår i: Ad hoc networks, ISSN 1570-8705, E-ISSN 1570-8713, Vol. 43, s. 16-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, energy-efficient scheduling for grouped machine-type devices deployed in cellular networks isinvestigated. We introduce a scheduling-based cooperation incentivescheme which enables machine nodes to organize themselveslocally, create machine groups, and communicate through grouprepresentatives to the base station. This scheme benefits from anovel scheduler design which takes into account the cooperationlevel of each node, reimburses the extra energy consumptionsof group representatives, and maximizes the network lifetime.As reusing cellular uplink resources for communications insidethe groups degrades the Quality of Service (QoS) of theprimary users, analytical results are provided which present atradeoff between maximum allowable number of simultaneouslyactive machine groups in a given cell and QoS of the primaryusers. Furthermore, we extend our derived solutions for theexisting cellular networks, propose a cooperation-incentive LTEscheduler, and present our simulation results in the context ofLTE. The simulation results show that the proposed solutionssignificantly prolong the network lifetime. Also, it is shown thatunder certain circumstances, reusing uplink resource by machinedevices can degrade the outage performance of the primary userssignificantly, and hence, coexistence management of machinedevices and cellular users is of paramount importance for nextgenerations of cellular networks in order to enable group-basedmachine-type communications while guaranteeing QoS for theprimary users.

  • 2.
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    On the DoF and Secure DoF of K-User MIMO Interference Channel with Instantaneous Relays2019Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Interference channel, in which multiple user pairs communicate over shared resources, is a building block of communications networks. Here, the K-user interference channel (IC) aided by J instantaneous relays (IRs), i.e. relays without delay, is considered. For KICJR networks, where K>2 and J>1, the DoF performance and achievable schemes have not been investigated in literature. Here, we devise a novel achievable scheme, called restricted interference alignment (RIA), which restricts the received interference from each source at each destination in a limited sub-space, and then, aligns the restricted interferences. Furthermore, we develop an analytical tool for finding a tight upper bound on DoF of KICJR networks by analyzing the properness of the interference alignment equations. Moreover, we develop linear beamforming design for sources and relays based on the mean square error (MSE) minimization, as an achievable scheme. The performance evaluation results show that the achievable sum DoF by using the proposed RIA scheme and the MSE-based beamforming design match well with the derived upper bounds. Furthermore, the results confirm that the achieved sum DoF using the RIA scheme outperforms the existing achievable schemes. Motivated by these promising results, we further investigate impact of IRs in providing physical layer security, i.e. achieving secure DoF in interference networks. Specifically, we derive a lower bound on the achievable secure DoF by devising an achievable scheme, called transmission in the null space (TNS). This scheme makes the cross channels rank deficient and enables sources to select their transmit filters in the constructed null spaces. Performance evaluation shows that by leveraging IRs, the secure DoF performance of interference networks could be increased significantly. The proposed analytical framework in this work for rank deficiency-powered DoF analysis is expected to also attract attention from other research areas, e.g. beamforming design for millimeter wave communications.

  • 3.
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Serving IoT Communications over Cellular Networks: Challenges and Solutions in Radio Resource Management for Massive and Critical IoT Communications2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Internet of Things (IoT) communications refer to the interconnections of smart devices, with reduced human intervention, which enable them to participate more actively in everyday life. It is expected that introduction of a scalable, energy efficient, and reliable IoT connectivity solution can bring enormous benefits to the society, especially in healthcare, wellbeing, and smart homes and industries. In the last two decades, there have been efforts in academia and industry to enable IoT connectivity over the legacy communications infrastructure. In recent years, it is becoming more and more clear that the characteristics and requirements of the IoT traffic are way different from the legacy traffic originating from existing communications services like voice and web surfing, and hence, IoT-specific communications systems and protocols have received profound attention. Until now, several revolutionary solutions, including cellular narrowband-IoT, SigFox, and LoRaWAN, have been proposed/implemented. As each of these solutions focuses on a subset of performance indicators at the cost of sacrificing the others, there is still lack of a dominant player in the market capable of delivering scalable, energy efficient, and reliable IoT connectivity. The present work is devoted to characterizing state-of-the-art technologies for enabling large-scale IoT connectivity, their limitations, and our contributions in performance assessment and enhancement for them. Especially, we focus on grant-free radio access and investigate its applications in supporting massive and critical IoT communications. The main contributions presented in this work include (a) developing an analytical framework for energy/latency/reliability assessment of IoT communications over grant-based and grant-free systems; (b) developing advanced RRM techniques for energy and spectrum efficient serving of massive and critical IoT communications, respectively; and (c) developing advanced data transmission/reception protocols for grant-free IoT networks. The performance evaluation results indicate that supporting IoT devices with stringent energy/delay constraints over limited radio resources calls for aggressive technologies breaking the barrier of the legacy interference-free orthogonal communications.

  • 4.
    Azari, Amin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Bria, Aurelian
    System and method for providing communication rules based on a status associated with a battery of a device2017Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The disclosure relates to communication systems and, more particularly, to a system and method for providing communication rules based on a status associated with a battery of a device.

  • 5.
    Azari, Amin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Cavdar, Cicek
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Performance Evaluation and Optimization of LPWA IoT Networks: A Stochastic Geometry Approach2018Inngår i: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, IEEE, 2018, artikkel-id 8647881Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Leveraging grant-free radio access for enabling low-power wide-area (LPWA) Internet of Things (IoT) connectivity has attracted lots of attention in recent years. Regarding lack of research on LPWA IoT networks, this work is devoted to reliability modeling, battery-lifetime analysis, and operation-control of such networks. We derive the interplay amongst density of the access points, communication bandwidth, volume of traffic from heterogeneous sources, and quality of service (QoS) in communications. The presented analytical framework comprises modeling of interference from heterogeneous sources with correlated deployment locations and time-frequency asynchronous radio-resource usage patterns. The derived expressions represent the operation regions and rates in which, energy and cost resources of devices and the access network, respectively, could be traded to achieve a given level of QoS in communications. For example, our expressions indicate the expected increase in QoS by increasing number of transmitted replicas, transmit power, density of the access points, and communication bandwidth. Our results further shed light on scalability of such networks and figure out the bounds up to which, scaling resources can compensate the increase in traffic volume and QoS demand. Finally, we present an energy-optimized operation control policy for IoT devices. The simulation results confirm tightness of the derived analytical expressions, and indicate usefulness of them in planning and operation control of IoT networks.

  • 6.
    Azari, Amin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Cavdar, Cicek
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Self-organized Low-power IoT Networks: A Distributed Learning Approach2018Inngår i: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Enabling large-scale energy-efficient Internet-ofthings (IoT) connectivity is an essential step towards realization of networked society. While legacy wide-area wireless systems are highly dependent on network-side coordination, the level of consumed energy in signaling, as well as the expected increase in the number of IoT devices, makes such centralized approaches infeasible in future. Here, we address this problem by self-coordination for IoT networks through learning from past communications. To this end, we first study low-complexity distributed learning approaches applicable in IoT communications. Then, we present a learning solution to adapt communication parameters of devices to the environment for maximizing energy efficiency and reliability in data transmissions. Furthermore, leveraging tools from stochastic geometry, we evaluate the performance of proposed distributed learning solution against the centralized coordination. Finally, we analyze the interplay amongst energy efficiency, reliability of communications against noise and interference over data channel, and reliability against adversarial interference over data and feedback channels. The simulation results indicate that compared to the state of the art approaches, both energy efficiency and reliability in IoT communications could be significantly improved using the proposed learning approach. These promising results, which are achieved using lightweight learning, make our solution favorable in many low-cost low-power IoT applications.

  • 7.
    Azari, Amin
    et al.
    Wireless Multimedia Communications Laboratory, Center of Excellence on Applied Electromagnetic Systems, University of Tehran, Iran .
    Harsini, Jalil
    Lahouti, Farshad
    Performance Analysis of Ad-Hoc Routing in Heterogeneous Clustered Multi-hop Wireless Networks2015Inngår i: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 80, s. 144-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper analyzes the performance of clustered decode-and-forward multi-hop relaying (CDFMR) wireless Rayleigh fading networks, and sheds light on their design principles for energy and spectral efficiency. The focus is on a general performance analysis (over all SNR range) of heterogeneous wireless networks with possibly different numbers of relays in clusters of various separations. For clustered multi-hop relaying systems, hop-by-hop routing is known as an efficient decentralized routing algorithm which selects the best relay node in each hop using local channel state information. In this article, we combine hop-by-hop routing and cooperative diversity in CDFMR systems, and we derive (i) a closed-form expression for the probability distribution of the end-to-end SNR at the destination node; (ii) the system symbol error rate (SER) performance for a wide class of modulation schemes; and (iii) exact analytical expressions for the system ergodic capacity, the outage probability and the achievable probability of the SNR (power) gain. We also provide simple analytical asymptotic expressions for SER and the outage probability in high SNR regime. Numerical results are provided to validate the correctness of the presented analyses.

  • 8.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Energy Efficient MAC for Cellular-Based M2M Communications2014Inngår i: Signal and Information Processing (GlobalSIP), 2014 IEEE Global Conference on, IEEE conference proceedings, 2014, s. 128-132Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Machine-to-Machine (M2M) networks, an energyefficient scalable medium access control (MAC) is crucial forserving massive battery-driven machine-type devices. In thispaper, we investigate the energy efficient MAC design to minimizebattery power consumption in cellular-based M2M communications.We present an energy efficient MAC protocol that notonly adapts contention and reservation-based protocols for M2Mcommunications in cellular networks, but also benefits frompartial clustering to handle the massive access problem. Then weinvestigate the energy efficiency and access capacity of contentionbasedprotocols and present an energy efficient contention-basedprotocol for intra-cluster communication of the proposed MAC,which results in huge power saving. The simulation results showthat the proposed MAC protocol outperforms the others in energysaving without sacrificing much delay or throughput. Also, thelifetimes of both individual nodes and the whole M2M networkare significantly extended.

  • 9.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Fundamental Tradeoffs in Resource Provisioning forIoT Services over Cellular Networks2017Inngår i: Proceedings of the 2017 IEEE International Conference on Communications, Institute of Electrical and Electronics Engineers (IEEE), 2017, artikkel-id 7996885Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Performance tradeoffs in resource provisioningfor mixed internet-of-things (IoT) and human-orientedcommunications(HoC) services over cellular networks are investigated.First, we present a low-complexity model of cellularconnectivity in the uplink direction in which both accessreservation and scheduled data transmission procedures areincluded. This model is employed subsequently in derivinganalytical expressions for energy efficiency, spectral efficiency,and experienced delay in data transmission of connected devicesas well as energy consumption of base stations. The derivedexpressions indicate that the choice of uplink resource provisioningstrategy introduces tradeoffs between battery lifetime forIoT communications, quality of service (QoS) for HoC, spectralefficiency and energy consumption for the access network. Then,the impacts of system and traffic parameters on the introducedtradeoffs are investigated. Performance analysis illustrates thatimproper resource provisioning for IoT traffic not only degradesQoS of high-priority services and decreases battery lifetime ofIoT devices, but also increases energy consumption of the accessnetwork. The presented analytical and simulations results figureout the ways in which spectral/energy efficiency for the accessnetwork and QoS for high-priority services could be traded toprolong battery lifetimes of connected devices by compromisingon the level of provisioned radio resources.

  • 10.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Lifetime-Aware Scheduling and Power Control for Cellular-based M2M Communications2015Inngår i: Wireless Communications and Networking Conference (WCNC), 2015 IEEE: , IEEE conference proceedings, 2015, s. 1171-1176Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper the uplink scheduling and transmit powercontrol is investigated to minimize the energy consumption forbattery-driven devices deployed in cellular networks. A lifetimemetric based on the accurate energy consumption model for cellularbasedmachine devices is provided and used to formulate theuplink scheduling and power control problems as network lifetimemaximization problems. Then, lifetime-aware uplink scheduling andpower control protocols which maximize the overall network lifetimeare investigated based on the different lifetime definitions. Besidesthe exact solutions, the low-complexity suboptimal solutions arepresented in this work which can achieve near optimal performancewith much lower computational complexity. The performance evaluationshows that the network lifetime is significantly extended underproposed protocols.

  • 11.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Lifetime-Aware Scheduling and Power Control for M2M Communications in LTE Networks2015Inngår i: Vehicular Technology Conference (VTC Spring), 2015 IEEE 81st, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper the scheduling and transmit powercontrol are investigated to minimize the energy consumptionfor battery-driven devices deployed in LTE networks. To enableefficient scheduling for a massive number of machine-typesubscribers, a novel distributed scheme is proposed to let machinenodes form local clusters and communicate with the base-stationthrough the cluster-heads. Then, uplink scheduling and powercontrol in LTE networks are introduced and lifetime-aware solu-tions are investigated to be used for the communication betweencluster-heads and the base-station. Beside the exact solutions,low-complexity suboptimal solutions are presented in this workwhich can achieve near optimal performance with much lowercomputational complexity. The performance evaluation showsthat the network lifetime is significantly extended using theproposed protocols.

  • 12.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Network Life time Maximization for Cellular-Based M2M Networks2017Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 5, s. 18927-18940, artikkel-id 8045999Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High energy efficiency is critical for enabling massive machine-type communications (MTC) over cellular networks. This paper is devoted to energy consumption modeling, battery lifetime analysis, lifetime-aware scheduling, and transmit power control for massive MTC over cellular networks. We consider a realistic energy consumption model for MTC and model network battery-lifetime. Analytic expressions are derived to demonstrate the impact of scheduling on both the individual and network battery lifetimes. The derived expressions are subsequently employed in the uplink scheduling and transmit power control for mixed-priority MTC traffic in order to maximize the network lifetime. Besides the main solutions, low complexity solutions with limited feedback requirement are investigated, and the results are extended to existing LIE networks. In addition, the energy efficiency, spectral efficiency, and network lifetime tradeoffs in resource provisioning and scheduling for MTC over cellular networks are investigated. The simulation results show that the proposed solutions can provide substantial network lifetime improvement and network maintenance cost reduction in comparison with the existing scheduling schemes.

  • 13.
    Azari, Amin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Network Lifetime Maximization for Cellular-Based M2M Networks2017Inngår i: IEEE Access, E-ISSN 2169-3536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High energy efficiency is critical for enabling massivemachine-type communications (MTC) over cellular networks.This work is devoted to energy consumption modeling,battery lifetime analysis, lifetime-aware scheduling and transmitpower control for massive MTC over cellular networks. Weconsider a realistic energy consumption model for MTC andmodel network battery-lifetime. Analytic expressions are derivedto demonstrate the impact of scheduling on both the individualand network battery lifetimes. The derived expressions aresubsequently employed in uplink scheduling and transmit powercontrol for mixed-priority MTC traffic in order to maximizethe network lifetime. Besides the main solutions, low-complexitysolutions with limited feedback requirement are investigated,and the results are extended to existing LTE networks. Also,the energy efficiency, spectral efficiency, and network lifetimetradeoffs in resource provisioning and scheduling for MTC overcellular networks are investigated. The simulation results showthat the proposed solutions can provide substantial networklifetime improvement and network maintenance cost reductionin comparison with the existing scheduling schemes.

  • 14.
    Azari, Amin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Stefanovic, Cedomir
    Aalborg University.
    Popovski, Petar
    Aalborg University.
    Latency-Energy Tradeoff based on Channel Scheduling and Repetitions in NB-IoT Systems2018Inngår i: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018, artikkel-id 8648024Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Narrowband Internet of Things (NB-IoT) is the latest IoT connectivity solution presented by the 3rd generation partnership project (3GPP). NB-IoT introduces coverage classes and offers a significant link budget improvement by allowing repeated transmissions by nodes that experience high path loss. However, those repetitions necessarily increase the energy consumption and the latency in the whole NB-IoT system. The extent to which the whole system is affected depends on the scheduling of the uplink and downlink channels. We address this question, not treated previously, by developing a tractable model of NB-IoT access protocol operation, comprising message exchanges in random-access, control, and data channels, both in the uplink and downlink The model is then used to analyze the impact of channel scheduling as well as the interaction of coexisting coverage classes, through derivation of the expected latency and battery lifetime for each coverage class. These results are subsequently employed in investigation of latency-energy tradeoff in NB-IoT channel scheduling as well as determining the optimized operation points. Simulations results show validity of the analysis and confirm that channel scheduling and coexistence of coverage classes significantly affect latency and battery lifetime performance of NB-IoT devices.

  • 15.
    Azari, Amin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Popovski, Petar
    Stefanovic, Cedomir
    Cavdar, Cicek
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Grant-Free Radio Access for Cellular IoTManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Radio resource management (RRM) is a major factor affecting the delay, reliability, and energy consumption of Internet of Things (IoT) communications. This article is focused on grant-free access, a class of techniques suited to support massive IoT connectivity. Within the proposed scheme, the IoT devices transmit multiple replicas of the same packet. In addition to that, the receiver makes use of the random timing and frequency offsets in order to carry out Successive Interference Cancellation (SIC). The system performance is investigated by using a model based on stochastic geometry, leading to closed-form expressions for the key performance indicators, such as reliability and battery lifetime. The framework allows optimization of the number of replicas per device. This results in overall improvement of the energy consumption, delay and reliability, at the expense of more complex processing at the Base Station. The evaluation results indicate that the proposed data transmission and reception schemes can significantly prolong battery lifetime of IoT devices by removing the need for connection establishment and reducing the number of retransmissions. The obtained results also indicate existence of traffic-load regions, where grant-free radio access outperforms the grant-based one, which is used in LTE and NB-IoT systems. These results pave the way for enabling intelligent grant-based/free operation mode switching in 5G networks.

  • 16.
    Hossain, Mohammad Istiak
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Collision Multiplicity Detection: Challenges, Solutions, and Impacts on Cellular Random Access2020Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In cellular and cellular-IoT systems, random access has the utmost importance as it is the gatekeeper that assures conflict-free access to radio resources. The main drawback of the legacy protocols lies at the collision resolution procedure as the base station (BS) is blind to the collision multiplicity and collided devices rely on the BSs for contention resolution. While contention resolution over the random access channel (RACH) is mature in the literature, most studies are following optimistic assumptions in which the full collision impact at the receiver is neglected, and a simplified model of partially overlapping packets is considered. This work is devoted to the investigation of a more realistic model of collision in cellular networks with the aim to investigate challenges and potential solutions in preamble detection in collision scenarios. The simulation results show that besides previously well-known challenges in dealing with collisions, the occurrence of collisions significantly increases the probability of false preamble detection.

  • 17.
    Hossain, Mohammad Istiak
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Islam, Raihan Ul
    Luleå University of Technology.
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Andersson, Karl
    Luleå University of Technology.
    Early Data Transmit in Cellular-IoT: A Supervised Learning Approach to Optimized Resource Pool Allocation2020Inngår i: Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    3GPP introduced Early Data Transmit (EDT) protocol in release-15 to address Internet of things (IoT) services signaling cost and connection delay due to RRC connectivity procedure. EDT enables data transmission in MSG3 wherein traditional RACH procedure, a collision is realized at MSG3 reception. Traditional preventive approach (access class barring) may control the device access rate, but that does not always adequate to solve hidden collision due to the receiver’s limitation and devices power control mechanism. The present work aims at solving the problem by allocating extra resources pool for potential collided devices. The allocated resource of the pool is optimized based on an artificial neural network (ANN) based learning algorithm. The performance evaluation result shows that the learning-based resource allocation radically increases the data transmission success rate with EDT.

  • 18.
    Masoudi, Meysam
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Yavuz, E. A.
    Ericsson AB, Stockholm, Sweden.
    Cavdar, Cicek
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Grant-Free Radio Access IoT Networks: Scalability Analysis in Coexistence Scenarios2018Inngår i: IEEE International Conference on Communications, Institute of Electrical and Electronics Engineers Inc. , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    IoT networks with grant-free radio access, like SigFox and LoRa, offer low-cost durable communications over unlicensed band. These networks are becoming more and more popular due to the ever-increasing need for ultra durable, in terms of battery lifetime, IoT networks. Most studies evaluate the system performance assuming single radio access technology deployment. In this paper, we study the impact of coexisting competing radio access technologies on the system performance. Considering K technologies, defined by time and frequency activity factors, bandwidth, and power, which share a set of radio resources, we derive closed-form expressions for the successful transmission probability, expected battery lifetime, and experienced delay as a function of distance to the serving access point. Our analytical model, which is validated by simulation results, provides a tool to evaluate the coexistence scenarios and analyze how introduction of a new coexisting technology may degrade the system performance in terms of success probability and battery lifetime. We further investigate solutions in which this destructive effect could be compensated, e.g., by densifying the network to a certain extent and utilizing joint reception.

  • 19.
    Masoudi, Meysam
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Yavuz, Emre Altug
    Ericsson AB, Stockholm, Sweden.
    Cavdar, Cicek
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Grant-free Radio Access IoT Networks:Scalability Analysis in Coexistence Scenarios2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    IoT networks with grant-free radio access, likeSigFox and LoRa, offer low-cost durable communications overunlicensed band. These networks are becoming more and morepopular due to the ever-increasing need for ultra durable, interms of battery lifetime, IoT networks. Most studies evaluatethe system performance assuming single radio access technologydeployment. In this paper, we study the impact of coexistingcompeting radio access technologies on the system performance.Considering K technologies, defined by time and frequencyactivity factors, bandwidth, and power, which share a set of radioresources, we derive closed-form expressions for the successfultransmission probability, expected battery lifetime, and experienceddelay as a function of distance to the serving access point.Our analytical model, which is validated by simulation results,provides a tool to evaluate the coexistence scenarios and analyzehow introduction of a new coexisting technology may degrade thesystem performance in terms of success probability and batterylifetime. We further investigate solutions in which this destructiveeffect could be compensated, e.g., by densifying the network toa certain extent and utilizing joint reception.

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