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 soft-cell operation involving legacy devices

Abstract: The teachings herein provide a number of advantages, including but not limited to improving soft-cell operation in service scenarios involving legacy devices that do not directly support carrier aggregation—i.e., devices that can transmit or receive in only one frequency band at a time. By imposing a Time Division Duplex (TDD) arrangement across two carriers operating in different frequency bands, scheduled transmissions involving the legacy device are mutually exclusive as between the two carriers. Advantageously, the TDD arrangement is imposed across first and second carriers used in the macro- and low-power layers of a soft-cell, thus imposing TDD-based coordination of scheduled transmissions between those carriers irrespective of whether the individual carriers are configured as Frequency Division Duplex (FDD) or TDD carriers, or a mix thereof.

High-Speed Downlink packet access

Abstract: This chapter discusses high-speed downlink packet access (HSDPA). It provides a description of HSDPA, including how several of the basic technologies have been incorporated in the wideband code division multiple access (WCDMA) radio access. The introduction of HSDPA implies a major extension of the WCDMA radio interface. It enhances the WCDMA downlink packet-data performance and capabilities in terms of higher peak data rate, reduced latency, and increased capacity. This is achieved through the introduction of several of the techniques, including higher-order modulation, rate control, channel-dependent scheduling, and hybrid automatic repeat request (ARQ) with soft combining. The chapter begins with an overview of HSDPA, where the key characteristics are explored. It discusses high-speed downlink shared channel (HS–DSCH), which is the transport channel used to support shared-channel transmission. The chapter provides finer details related to HSDPA. This includes physical-layer processing, constellation rearrangement, protocol operation, and others.

Transmission holes in longer transmission intervals

Abstract: In an aspect, a transmitting node schedules a downlink transmission to a first UE over a first transmission interval having a predetermined length and starts the downlink transmission to the first UE in the first transmission interval. The transmitting node stops the downlink transmission to the first UE prior to an end of the first transmission interval to create a first end of a transmission hole in the downlink transmission to the first UE and resumes the downlink transmission to the first UE at a second end of the transmission hole. The transmitting node may receive an uplink transmission from a second UE or transmit a higher priority transmission, within the transmission hole.

Methods and devices for sending and receiving location information for wireless devices

Abstract: The embodiments herein relate to a method in a first device (101) for informing a second device (105) that an identity associated with the first device (101) is at a certain location The first device (101) obtains information about the location of the first device (101) The first device (101) broadcasts, by means of device to device, D2D, communication, a message to be received by the second device (105) The message comprises the location information and an identity information associated with a user of the first device (101) The location information is transmitted on a first communications resource and the identity information is transmitted on a second communications resource

Receiver-specific transmission length

Abstract: Techniques for selecting and utilizing one or more novel symbol structures, control signaling, and scheduling for wireless signal transmission/reception are presented. An example method is presented that includes determining (302), based on control information corresponding to a slot, that a user equipment (UE) (102A) or another UE (102B) in communication with a network node (106) is to transmit acknowledgement (ACK) or negative acknowledgement (NACK) feedback in the slot for a downlink signal received by the UE (102A) or the other UE (102B) in the slot. In addition, the example method includes transmitting (304) an intermediate uplink signal to the network node (106) and/or receiving an intermediate downlink signal from the network node (106) after the downlink signal is fully received and before transmission of the ACK or NACK feedback begins. Example apparatuses, such as UEs and network nodes, and computer programs/code are also presented.

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. >