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.

Two stage data packet processing scheme

Abstract: The present invention provides an efficient and flexible arrangement for quickly combining a number of data packets to fit into a transmission interval. A current communications condition, e.g., the current channel quality, is detected and used to select an appropriate combination of modulation and channel encoding parameters. However, data packets are combined and pre-encoded before the modulation and/or coding scheme (MCS) to be used in a specific transmission interval is known. Once the MCS is known for the transmission interval, an appropriate number of pre-processed data blocks are combined. Using the present invention, some complex packet processing operations can be performed in advance, without any knowledge of the MCS. Another advantage of a preferred implementation of the invention is that the block size of the channel encoder is increased because several data packets are combined before encoding. A large block size improves the performance of many types of channel encoder structures. Further, acknowledgement/negative-acknowledgement signals may be sent for groups of data packets rather than for individual data packets, thereby reducing the amount of required control signaling and simplifying soft combining in the receiver.

Detection and efficient use of broadcast-only modes of cellular communication system operation

Abstract: Operation of a network node (800) in a mobile communication system that serves a User Equipment (UE) includes ascertaining (801 ) whether the network node (800) is operating in a broadcast-only mode. If so, then broadcast channel information is transmitted (803) on a physical multicast/broadcast channel (MCH). Otherwise, the broadcast channel information is transmitted (805) on a physical broadcast channel (BCH). To inform the UE of where to find the broadcast channel information, the network node (800) transmits (807) an indicator to the UE, wherein the indicator indicates whether the broadcast channel information is conveyed via the physical broadcast channel (BCH) or the physical multicast/broadcast channel (MCH). The indicator can be included within signals that are also used to enable a UE's cell search procedure.

Key Technology for 5G New Radio

Abstract: The articles in this special section focus on 5G mobile communication. With initial commercialization expected in 2020, fifth generation (5G) mobile communications is gathering increased interest and momentum around the world. Following discussions on the 5G vision and key requirements such as high data rate, low latency, and massive connectivity, various candidate technologies have been proposed and investigated. These new technologies include massive antenna technologies to provide beamforming gain and support increased capacity, new waveforms to flexibly accommodate various services and applications with different requirements, and new multiple access schemes to support massive connections. From a spectrum point of view, there is also increased interest in the use of spectrum above 6 GHz for 5G mobile communications.

Cell search and measurement in heterogeneous networks

Abstract: An extended cell search procedure enables more inclusive measurement reports by mobile terminals operating in a heterogeneous network. The mobile terminal may be configured to conduct an extended cell search to enable better detection of signals transmitted from weaker cells. For mobile terminal with extended cell search capabilities, the network sends an extended cell search message to the mobile terminal when there is a need for an extended cell search. In response to the extended cell search message, the mobile terminal uses an extended cell search procedure rather than the normal cell search procedure (as specified in Rel-8 of the LTE standard) when performing cell searches.

Preamble sets matched to uplink transmission conditions

Abstract: The present disclosure relates to random access in wireless communication systems, and in particular to transmitting, receiving, and detecting preamble sequences A method in a wireless device for transmitting a preamble sequence to a network node is disclosed The method comprises configuring (S12) a number of preamble sequences into two or more preamble sets, wherein each preamble set is associated with at least one respective uplink transmission condition; determining (S13) a transmission condition of an uplink from the wireless device to the network node; and selecting (S14) one out of the two or more preamble sets based on the determined transmission condition to be a selected preamble set, and a preamble sequence from the selected preamble set to be a selected preamble sequence; as well as transmitting (S15) the selected preamble sequence on the uplink

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. >