Stefan Parkvall

Bio: Stefan Parkvall is an academic researcher from Ericsson. The author has contributed to research in topics: Telecommunications link & Node (networking). The author has an hindex of 58, co-authored 502 publications receiving 19083 citations. Previous affiliations of Stefan Parkvall include Royal Institute of Technology & University of California, San Diego.

Method and apparatus for reducing co-channel interference

Abstract: A method for providing co-channel interference information by a network node includes receiving information for at least one user equipment (UE) connected to an adjacent network node, determining a co-channel interference list for user equipment (UE) connected to the network node wherein the co-channel interference list is based on the received information and transmitting the co-channel interference list to a UE connected to the network node.

Improved handling of simultaneous network communication transmission and d2d communication transmission

Abstract: A radio frequency communication device (100) comprising a radio frequency communications interface (130) and a controller (110), wherein said controller (110) is configured to establish network communication with a network node (310) and to establish device-to-device communication with a second radio frequency communication device (325) via said radio frequency communication interface (130). The controller is further configured to determine whether there is to be performed a simultaneous transmission comprising a network transmission over said network communication with said network node (310) and a D2D transmission over said device- to-device communication with said second radio frequency communication device (325); determine if there is a transmission problem related to said simultaneous transmission; and if so determine a mitigation technique; and perform said network transmission and said D2D transmission according to said mitigation technique to mitigate said transmission problem.

LTE physical layer

Abstract: Publisher Summary This chapter describes lowest of the protocol layers of the Long-Term Evolution (LTE) radio-interface architecture, the LTE physical layer. It provides detailed information on processing and control signaling for the orthogonal frequency division multiplex (OFDM) downlink transmission and the Single-Carrier frequency division multiple access (FDMA) uplink. The chapter begins with a discussion on the overall time-domain structure for LTE transmission. This is followed by LTE downlink transmission scheme, which is based on OFDM. The basic LTE downlink physical resource can be seen as a time-frequency resource grid, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval. Finally, the chapter describes the LTE uplink transmission scheme, which is based on so-called DFTS–OFDM transmission. DFTS–OFDM is a low-PAR “single-carrier” transmission scheme that allows for flexible bandwidth assignment and orthogonal multiple access not only in the time domain but also in the frequency domain. Thus, the LTE uplink transmission scheme is also referred to as “single-carrier FDMA (SC-FDMA).” LTE uplink transmission is limited to localized transmission.

Signalling Resource Allocation in a Telecommunications Network

Abstract: The present invention provides a method, a radio base station (40) and a mobile terminal (50) for allocating resources in a telecommunications network, where communications between the radio base station (40) and the mobile terminal (50) take place over a plurality of carriers. The method comprises transmitting and receiving a resource allocation message comprising one or more bits. Each of the bits corresponds to a number of resource blocks, where the number is determined from the ratio of the aggregate bandwidth of the plurality of carriers divided by the bandwidth of the carrier over which the resource allocation message is sent.

Uplink Power Control for Power Limited Terminals

Abstract: Transmit power control methods and apparatus are disclosed. In several embodiments, a mobile terminal is configured to effectively ignore “UP” transmit power control commands in the event that the mobile terminal is operating in a power-limited state. In an exemplary method for controlling transmit power at a mobile terminal, a plurality of transmit power control commands are received. An accumulated power control value is adjusted in response to each transmit power control command that directs a negative adjustment in transmit power. However, the accumulated power control value is adjusted in response to a transmit power control command that directs a positive adjustment in transmit power only if the mobile terminal is not in a power-limited state. Transmit power settings for each transmission are calculated based on the accumulated power control value and the one or more radio link parameters.

Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas

Abstract: A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval. Time-division duplex operation combined with reverse-link pilots enables the base station to estimate the reciprocal forward- and reverse-link channels. The conjugate-transpose of the channel estimates are used as a linear precoder and combiner respectively on the forward and reverse links. Propagation, unknown to both terminals and base station, comprises fast fading, log-normal shadow fading, and geometric attenuation. In the limit of an infinite number of antennas a complete multi-cellular analysis, which accounts for inter-cellular interference and the overhead and errors associated with channel-state information, yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve. In particular the effects of uncorrelated noise and fast fading vanish, throughput and the number of terminals are independent of the size of the cells, spectral efficiency is independent of bandwidth, and the required transmitted energy per bit vanishes. The only remaining impairment is inter-cellular interference caused by re-use of the pilot sequences in other cells (pilot contamination) which does not vanish with unlimited number of antennas.

Scaling Up MIMO: Opportunities and Challenges with Very Large Arrays

Abstract: Multiple-input multiple-output (MIMO) technology is maturing and is being incorporated into emerging wireless broadband standards like long-term evolution (LTE) [1]. For example, the LTE standard allows for up to eight antenna ports at the base station. Basically, the more antennas the transmitter/receiver is equipped with, and the more degrees of freedom that the propagation channel can provide, the better the performance in terms of data rate or link reliability. More precisely, on a quasi static channel where a code word spans across only one time and frequency coherence interval, the reliability of a point-to-point MIMO link scales according to Prob(link outage) ` SNR-ntnr where nt and nr are the numbers of transmit and receive antennas, respectively, and signal-to-noise ratio is denoted by SNR. On a channel that varies rapidly as a function of time and frequency, and where circumstances permit coding across many channel coherence intervals, the achievable rate scales as min(nt, nr) log(1 + SNR). The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time [2].

Two decades of array signal processing research: the parametric approach

Abstract: The quintessential goal of sensor array signal processing is the estimation of parameters by fusing temporal and spatial information, captured via sampling a wavefield with a set of judiciously placed antenna sensors. The wavefield is assumed to be generated by a finite number of emitters, and contains information about signal parameters characterizing the emitters. A review of the area of array processing is given. The focus is on parameter estimation methods, and many relevant problems are only briefly mentioned. We emphasize the relatively more recent subspace-based methods in relation to beamforming. The article consists of background material and of the basic problem formulation. Then we introduce spectral-based algorithmic solutions to the signal parameter estimation problem. We contrast these suboptimal solutions to parametric methods. Techniques derived from maximum likelihood principles as well as geometric arguments are covered. Later, a number of more specialized research topics are briefly reviewed. Then, we look at a number of real-world problems for which sensor array processing methods have been applied. We also include an example with real experimental data involving closely spaced emitters and highly correlated signals, as well as a manufacturing application example.

On the capacity of a cellular CDMA system

Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >