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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.


Papers
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Proceedings ArticleDOI
Eva Englund1, Ke Wang Helmersson1, M. Persson1, M. Samuelsson1, Stefan Parkvall1 
22 Apr 2003
TL;DR: The results indicate that performance gains when introducing HS-DSCH are significant, even if higher-order modulation is not available, and to take advantage of higher- order modulation in environments with significant time dispersion advanced receivers structures should be considered.
Abstract: To support high peak rates the possibility to use higher-order modulation is included in the WCDMA high-speed downlink shared channel (HS-DSCH). In an initial roll-out, higher-order modulation may not be available in all terminals and it is therefore interesting to understand to what extent enhancements offered by HS-OSCH depends on higher-order modulation. We study the impacts of higher-order modulation on HS-DSCH system performance. Our results indicate that performance gains when introducing HS-DSCH are significant, even if higher-order modulation is not available. When time dispersion is small, higher-order modulation may improve system throughput. To take advantage of higher-order modulation in environments with significant time dispersion advanced receivers structures should be considered. Furthermore, higher order modulation is found to be more sensitive to errors in the channel quality estimates.

8 citations

Journal ArticleDOI
TL;DR: Long Term Evolution (LTE) has become the most successful mobile wireless broadband technology, serving over one billion users as of the beginning of 2016, but there is still significant room for LTE to grow as a mobile technology.
Abstract: Long Term Evolution (LTE) has become the most successful mobile wireless broadband technology, serving over one billion users as of the beginning of 2016. However, looking at the penetration rate, LTE serves only 14.5 percent of the current 7.3 billion mobile subscriptions. Consequently, there is still significant room for LTE to grow as a mobile technology; it will be serving users for a long time to come.

7 citations

Patent
03 Nov 2014
TL;DR: In this article, a method for configuring a first cell of a cellular communication system in relation to a second cell of the cellular communication systems is presented, which comprises determining an offset between a first carrier frequency of the first cell and a second spectrum range defined by the second carrier frequency and the second bandwidth.
Abstract: A method is disclosed of a network node of a cellular communication system for configuring a first cell of the cellular communication system in relation to a second cell of the cellular communication system. A coverage area of the first cell and a coverage area of the second cell overlap, at least partly. The first cell is to be provided by a first base station of the cellular communication system and has a first bandwidth and the second cell is provided by a second base station of the cellular communication system and has a second bandwidth which is larger than the first bandwidth. The method comprises determining an offset between a first carrier frequency of the first cell and a second carrier frequency of the second cell and configuring the first base station to provide the first cell based on the first carrier frequency. A first spectrum range defined by the first carrier frequency and the first bandwidth is comprised within a second spectrum range defined by the second carrier frequency and the second bandwidth. The offset is determined such that control signaling of the second cell is aligned with control signaling of the first cell to reduce an impact of interference between the control signaling of the first cell and the control signaling of the second cell. Corresponding computer program product, arrangement and network node are also disclosed.

7 citations

Patent
25 Apr 2014
TL;DR: In this paper, the pico node's transmission power is reduced in some time intervals, thereby reducing the interference to a level where reception from the macro node is possible, which may be combined with the first approach in some cases.
Abstract: In a heterogeneous cell deployment a mobile terminal may need to receive control data transmissions from a macro node at the same time as a pico node is transmitting user data for the mobile terminal, using the same frequency or set of frequencies This can result in a problematic interference situation According to several embodiments of the present invention, at least one of two general approaches is used to mitigate the interference situation described above In a first approach, the pico node's transmission power is reduced in some time intervals, thereby reducing the interference to a level where reception from the macro node is possible In a second approach, which may be combined with the first approach in some cases, the data transmitted from the macro node is provided by the pico node, either alone or in combination with the macro node

7 citations

Patent
Stefan Parkvall1, Johan Torsner1
11 May 2004
TL;DR: In this article, a mechanism for improved data transmission between units in a telecommunication network, where at least one of the units utilizes multiple transport channels for transmitting data, is proposed, where acknowledgeable data transmission is started over a first transport channel if no other on-going acknowledgeability data transmission on a second transport channel starts or ends within a pre-defined or assigned transmission period for the first channel.
Abstract: A mechanism for improved data transmission between units in a telecommunication network, where at least one of the units utilizes multiple transport channels for transmitting data. An acknowledgeable data transmission is started over a first transport channel if no other on-going acknowledgeable data transmission on a second transport channel starts or ends within a pre-defined or assigned transmission period for the first channel. Thereby, unique identification of acknowledgements messages is enabled.

7 citations


Cited by
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Book
01 Jan 2005

9,038 citations

Journal ArticleDOI
Thomas L. Marzetta1
TL;DR: A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval and a complete multi-cellular analysis yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve.
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.

6,248 citations

Journal ArticleDOI
TL;DR: 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.
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].

5,158 citations

Journal ArticleDOI
TL;DR: The article consists of background material and of the basic problem formulation, and introduces spectral-based algorithmic solutions to the signal parameter estimation problem and contrast these suboptimal solutions to parametric methods.
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.

4,410 citations

Proceedings Article
01 Jan 1991
TL;DR: It is concluded that properly augmented and power-controlled multiple-cell CDMA (code division multiple access) promises a quantum increase in current cellular capacity.
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. >

2,951 citations