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.

Reference signal pattern

Abstract: A method in a node (110, 115) comprises generating (704) a frame structure comprising at least a first subframe (305, 405, 505), the first subframe comprising a first symbol (310A, 510A) and a second symbol (310B, 510B), each of the first and second symbols comprising a plurality of resource elements. The method comprises reserving (708) one or more of the plurality of resource elements in the first symbol for reference signals (335A-G, 435A-G, 535A-G), modulating (712) one or more of the reserved resource elements in the first symbol with reference symbols (335B-D, 435B-D, 535B-D), the modulated one or more of the reserved resource elements in the first symbol comprising a subset of the one or more reserved resource elements that overlap in frequency domain the data transmission carried in the second symbol, and transmitting (716) the at least one subframe to another node.

Scheduling and Rate Adaptation

Abstract: This chapter discusses the key radio-resource-management functionality relevant for LTE, including downlink and uplink scheduling and reporting of channel-state information.

Radio-Interface Architecture

Abstract: The overall architecture of the LTE radio-access network, as well as the corresponding core network, is discussed in this chapter. Following this introduction, a more detailed description of the radio-access network user-plane and control-plane protocols is provided.

Method and system to provide a continous wireless connection using a mobile station as relay

Abstract: A system and a method for wireless linking in a cellular communication system are disclosed such that a mobile station is maintained in simultaneous communication with at least a first node and a second node for access to the cellular communication system. Information going to and from the first node is not identical to the information going to and from the second node. In one embodiment the second node, or secondary access point is a relay node forwarding received information to and from the first node, or primary access point. In another embodiment the second node is another mobile station performing a direct mobile-to-mobile communication (MS-to-­MS). In still an embodiment a first wireless link to the first node is for control information only. In still a further embodiment a second wireless link to the second node is only for communication of information from the mobile station or only for communication of information to the mobile station.

Spectrum for 5G

Abstract: This chapter describes the internation al process for regulating spectrum and how the present IMT spectrum has been assinged by the ITU-R. Based on the outcome of the most recent WRC, the candidate 5G spectrum is presented together with all the operating bands specified for NR in 3GPP.

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. >