Magnus Lindström

Bio: Magnus Lindström is an academic researcher from Ericsson. The author has contributed to research in topics: User equipment & Node (networking). The author has an hindex of 22, co-authored 72 publications receiving 2512 citations.

LTE: the evolution of mobile broadband

Abstract: This article provides an overview of the LTE radio interface, recently approved by the 3GPP, together with a more in-depth description of its features such as spectrum flexibility, multi-antenna transmission, and inter-cell interference control. The performance of LTE and some of its key features is illustrated with simulation results. The article is concluded with an outlook into the future evolution of LTE.

The LTE link-layer design

Abstract: The LTE radio interface for 3GPP Release 8 was specified recently. This article describes the LTE link-layer protocols, which abstract the physical layer and adapt its characteristics to match the requirements of higher layer protocols. The LTE link-layer protocols are optimized for low delay and low overhead and are simpler than their counterparts in UTRAN. The state of- the-art LTE protocol design is the result of a careful crosslayer approach where the protocols interact with each other efficiently. This article provides a thorough overview of this protocol stack, including the sub-layers and corresponding interactions in between them, in a manner that is more intuitive than in the respective 3GPP specifications.

Method and Apparatus for Radio Link Failure Recovery in a Telecommunication System

Abstract: The teachings presented herein enable a user terminal to perform a fast recovery from a radio link failure. In one aspect, the improvement in recovery time is achieved by commanding or otherwise causing the user terminal to perform radio link failure (RLF) recovery at a cell that is known to possess the user context, while considering that this cell should yield good radio conditions (if not the best) to the user terminal. A cell may be predefined for use by the user terminal in recovering its radio connection. Based on providing signal strength thresholds to the user terminal, for use in determining whether to use a predefined cell for reconnecting to the network, the user terminal attempts RLF recovery first in the predefined cell. By providing user context to the predefined cell in advance of a recovery attempt by the user terminal, the time for recovery is lessened. Note that the user terminal also may infer which cells are preferred.

Method and mobile terminal providing priority-based uplink scheduling information

Abstract: A method and mobile terminal for providing uplink scheduling information to a scheduler in a wireless telecommunication system. When a logical channel having data available to transmit triggers a buffer status report, the mobile terminal determines whether a priority level associated with the logical channel exceeds a predefined threshold. If so, the mobile terminal performs a scheduling request procedure with the scheduler. If not, the mobile terminal delays the scheduling request procedure until a predefined timing event has occurred. The predefined timing event may be at least one of expiration of a timer, a radio bearer associated with the logical channel becoming active, and if the scheduling request procedure is being performed using a contention-based random access, contention resolution succeeding for the mobile terminal.

Prohibiting unnecessary scheduling requests for uplink grants

Abstract: Uplink transmission scheduling requests (SRs) may be prohibited for a lower priority data flow, logical channel group (e.g., VoIP configured with semi-persistent resource allocation), or other grouping but may still be triggered for higher priority traffic (e.g., data connected to a signaling radio bearer (SRB)). More efficient scheduling is also achieved by allowing an uplink transmission scheduler to distinguish between different priority flows or groups (e.g., LCGs) without a buffer status report (BSR), As a result, when a semi-persistent resource is scheduled for the lower priority data, there is less delay for high priority data while eliminating uplink and downlink control signaling, i.e., fewer scheduling requests (SRs) and uplink grants, for the lower priority data.

Finding your Way in the Fog: Towards a Comprehensive Definition of Fog Computing

Abstract: The cloud is migrating to the edge of the network, where routers themselves may become the virtualisation infrastructure, in an evolution labelled as "the fog". However, many other complementary technologies are reaching a high level of maturity. Their interplay may dramatically shift the information and communication technology landscape in the following years, bringing separate technologies into a common ground. This paper offers a comprehensive definition of the fog, comprehending technologies as diverse as cloud, sensor networks, peer-to-peer networks, network virtualisation functions or configuration management techniques. We highlight the main challenges faced by this potentially breakthrough technology amalgamation.

A Survey on Wireless Security: Technical Challenges, Recent Advances, and Future Trends

Abstract: Due to the broadcast nature of radio propagation, the wireless air interface is open and accessible to both authorized and illegitimate users. This completely differs from a wired network, where communicating devices are physically connected through cables and a node without direct association is unable to access the network for illicit activities. The open communications environment makes wireless transmissions more vulnerable than wired communications to malicious attacks, including both the passive eavesdropping for data interception and the active jamming for disrupting legitimate transmissions. Therefore, this paper is motivated to examine the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity, and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state of the art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. Several physical-layer security techniques are reviewed and compared, including information-theoretic security, artificial-noise-aided security, security-oriented beamforming, diversity-assisted security, and physical-layer key generation approaches. Since a jammer emitting radio signals can readily interfere with the legitimate wireless users, we also introduce the family of various jamming attacks and their countermeasures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer, and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

LTE: the evolution of mobile broadband

Abstract: This article provides an overview of the LTE radio interface, recently approved by the 3GPP, together with a more in-depth description of its features such as spectrum flexibility, multi-antenna transmission, and inter-cell interference control. The performance of LTE and some of its key features is illustrated with simulation results. The article is concluded with an outlook into the future evolution of LTE.

A Survey of Research on Cloud Robotics and Automation

Abstract: The Cloud infrastructure and its extensive set of Internet-accessible resources has potential to provide significant benefits to robots and automation systems. We consider robots and automation systems that rely on data or code from a network to support their operation, i.e., where not all sensing, computation, and memory is integrated into a standalone system. This survey is organized around four potential benefits of the Cloud: 1) Big Data: access to libraries of images, maps, trajectories, and descriptive data; 2) Cloud Computing: access to parallel grid computing on demand for statistical analysis, learning, and motion planning; 3) Collective Robot Learning: robots sharing trajectories, control policies, and outcomes; and 4) Human Computation: use of crowdsourcing to tap human skills for analyzing images and video, classification, learning, and error recovery. The Cloud can also improve robots and automation systems by providing access to: a) datasets, publications, models, benchmarks, and simulation tools; b) open competitions for designs and systems; and c) open-source software. This survey includes over 150 references on results and open challenges. A website with new developments and updates is available at: http://goldberg.berkeley.edu/cloud-robotics/

Coordinated multipoint transmission/reception techniques for LTE-advanced [Coordinated and Distributed MIMO]

Abstract: This article presents an elaborate coordination technique among multiple cell sites called coordinated multipoint transmission and reception in the Third Generation Partnership Project for LTE-Advanced. After addressing major radio access techniques in the LTE Release 8 specifications, system requirements and applied radio access techniques that satisfy the requirements for LTE-Advanced are described including CoMP transmission and reception. Then CoMP transmission and reception schemes and the related radio interface, which were agreed upon or are currently being discussed in the 3GPP, are presented. Finally, system-level simulation evaluations show that the CoMP transmission and reception schemes have a significant effect in terms of improving the cell edge user throughput based on LTE-Advanced simulation conditions.