liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Karipidis, Eleftherios
Publications (10 of 37) Show all publications
Karipidis, E., Yuan, D., He, Q. & Larsson, E. G. (2015). Max-Min Power Control in Wireless Networks With Successive Interference Cancelation. IEEE Transactions on Wireless Communications, 14(11), 6269-6282
Open this publication in new window or tab >>Max-Min Power Control in Wireless Networks With Successive Interference Cancelation
2015 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 14, no 11, p. 6269-6282Article in journal (Refereed) Published
Abstract [en]

We consider a wireless network comprising a number of cochannel (hence mutually interfering) links. We study the power control problem of maximizing the rate that all links can simultaneously support under a novel setup, where receivers have interference cancelation (IC) capabilities. The problem of allocating the transmitting power is intertwined with determining the links on which receivers can perform IC and the order of cancelations. We provide and prove the theoretical results of the problem complexity and structural properties. For the problem solution, we propose a mixed-integer linear programming framework that enables jointly determining the optimal power and the IC patterns using off-the-shelf algorithms. This allows for the accurate assessment of the potential of IC for power control. Extensive numerical results are presented for performance evaluation, demonstrating the benefit of deploying IC in power control.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2015
Keywords
Optimization; power control; successive interference cancellation; wireless networks
National Category
Telecommunications Communication Systems Signal Processing
Identifiers
urn:nbn:se:liu:diva-123332 (URN)10.1109/TWC.2015.2451653 (DOI)000365046100029 ()
Note

Funding Agencies|Swedish Research Council (VR); Swedish Foundation of Strategic Research (SSF); Excellence Center at Linkoping-Lund in Information Technology (ELLIIT); European FP7 Marie Curie Project [324515, 329313]

Available from: 2015-12-14 Created: 2015-12-11 Last updated: 2018-08-14
Fathi, M. & Karipidis, E. (2014). Distributed allocation of subcarrier, power and bit-level in multicell orthogonal frequency-division multiple-access networks. IET COMMUNICATIONS, 8(6), 781-788
Open this publication in new window or tab >>Distributed allocation of subcarrier, power and bit-level in multicell orthogonal frequency-division multiple-access networks
2014 (English)In: IET COMMUNICATIONS, ISSN 1751-8628, Vol. 8, no 6, p. 781-788Article in journal (Refereed) Published
Abstract [en]

The downlink of multicell orthogonal frequency-division multiple-access (OFDMA) networks is studied, and the adaptive allocation of spectrum, power and rate is addressed. The authors consider networks with adaptive frequency reuse and discrete-level rates. Initially, the joint allocation problem is formulated as a centralised non-linear mixed-integer program (MIP), which is computationally intractable to solve optimally for practical problem sizes. Then, the capability of the receivers is exploited to estimate the subcarrier channel gains and the joint allocation problem is accordingly decomposed into subproblems, each of which is solved by a different base station with linear complexity. In the proposed iterative algorithm, the base stations perform rate and receiver allocation per subcarrier, with concurrent iterations. A filtering method is introduced to further decrease the algorithm complexity. Furthermore, for benchmarking purposes, the authors transform the original non-linear MIP to a linear MIP and find the optimal solution by means of standard branch-and-cut solvers. The merit of the proposed algorithm is demonstrated with numerical comparisons of its performance against the solutions of the linear MIP and the iterative waterfilling algorithm.

Place, publisher, year, edition, pages
Institution of Engineering and Technology (IET), 2014
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-106965 (URN)10.1049/iet-com.2013.0463 (DOI)000333981000001 ()
Available from: 2014-06-04 Created: 2014-06-02 Last updated: 2014-06-04
Jorswieck, E. A., Badia, L., Fahldieck, T., Karipidis, E. & Luo, J. (2014). Spectrum sharing improves the network efficiency for cellular operators. IEEE Communications Magazine, 52(3), 129-136
Open this publication in new window or tab >>Spectrum sharing improves the network efficiency for cellular operators
Show others...
2014 (English)In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 52, no 3, p. 129-136Article in journal (Refereed) Published
Abstract [en]

The paper describes the potential gain by spectrum sharing between cellular operators in terms of network efficiency. The focus of the study is on a specific resource sharing scenario: spectrum sharing between two operators in cellular downlink transmission. If frequency bands are allocated dynamically and exclusively to one operator – a case called orthogonal spectrum sharing – significant gains in terms of achievable throughput (spectrum sharing gains between 50% and 100%) and user satisfaction are reported for asymmetric scenarios at link and system level as well as from two hardware demonstrators. Additionally, if frequency bands are allocated simultaneously to two operators – a case called non-orthogonal spectrum sharing – further gains are reported. In order to achieve these, different enablers from hardware technologies and base station capabilities are required. However, we argue that all requirements are fulfilled in 3GPP and newer mobile standards. Therefore, the results and conclusions of this overview paper encourage to seriously consider the inter-operator spectrum sharing technologies.

Place, publisher, year, edition, pages
IEEE Communications Society, 2014
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:liu:diva-94753 (URN)10.1109/MCOM.2014.6766097 (DOI)000333105100020 ()
Funder
EU, FP7, Seventh Framework Programme, 248001
Available from: 2013-07-02 Created: 2013-07-02 Last updated: 2017-12-06
Lindblom, J., Karipidis, E. & Larsson, E. G. (2013). Achievable Outage Rate Regions for the MISO Interference Channel. IEEE Wireless Communications Letters, 2(4), 439-442
Open this publication in new window or tab >>Achievable Outage Rate Regions for the MISO Interference Channel
2013 (English)In: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 2, no 4, p. 439-442Article in journal (Refereed) Published
Abstract [en]

We consider the slow-fading two-user multiple-input single-output (MISO) interference channel. We want to understand which rate points can be achieved, allowing a non-zero outage probability. We do so by defining four different outage rate regions. The definitions differ on whether the rates are declared in outage jointly or individually and whether the transmitters have instantaneous or statistical channel state information (CSI). The focus is on the instantaneous CSI case with individual outage, where we propose a stochastic mapping from the rate point and the channel realization to the beamforming vectors. A major contribution is that we prove that the stochastic component of this mapping is independent of the actual channel realization.

Place, publisher, year, edition, pages
IEEE Communications Society, 2013
Keywords
Achievable rate region, beamforming, interference channel, MISO, outage probability
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-91840 (URN)10.1109/WCL.2013.051513.130186 (DOI)000209696800019 ()
Funder
EU, FP7, Seventh Framework Programme, 248001ELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsSwedish Foundation for Strategic Research Swedish Research Council
Note

At the time for thesis presentation publication was in status: Manuscript

Available from: 2013-05-02 Created: 2013-05-02 Last updated: 2017-12-06Bibliographically approved
Lindblom, J., Karipidis, E. & Larsson, E. G. (2013). Efficient Computation of Pareto Optimal Beamforming Vectors for the MISO Interference Channel with Successive Interference Cancellation. IEEE Transactions on Signal Processing, 61(19), 4782-4795
Open this publication in new window or tab >>Efficient Computation of Pareto Optimal Beamforming Vectors for the MISO Interference Channel with Successive Interference Cancellation
2013 (English)In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 61, no 19, p. 4782-4795Article in journal (Refereed) Published
Abstract [en]

We study the two-user multiple-input single-output (MISO) Gaussian interference channel where the transmitters have perfect channel state information and employ single-stream beamforming. The receivers are capable of performing successive interference cancellation, so when the interfering signal is strong enough, it can be decoded, treating the desired signal as noise, and subtracted from the received signal, before the desired signal is decoded. We propose efficient methods to compute the Pareto-optimal rate points and corresponding beamforming vector pairs, by maximizing the rate of one link given the rate of the other link. We do so by splitting the original problem into four subproblems corresponding to the combinations of the receivers' decoding strategies-either decode the interference or treat it as additive noise. We utilize recently proposed parameterizations of the optimal beamforming vectors to equivalently reformulate each subproblem as a quasi-concave problem, which we solve very efficiently either analytically or via scalar numerical optimization. The computational complexity of the proposed methods is several orders-of-magnitude less than the complexity of the state-of-the-art methods. We use the proposed methods to illustrate the effect of the strength and spatial correlation of the channels on the shape of the rate region.

Place, publisher, year, edition, pages
IEEE Signal Processing Society, 2013
Keywords
Beamforming, interference channel, interference cancellation, multiple-input single-output (MISO), Pareto boundary, Pareto optimality, rate region.
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-93845 (URN)10.1109/TSP.2013.2271748 (DOI)000324342900012 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research eLLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsEU, FP7, Seventh Framework Programme, 248001
Available from: 2013-06-11 Created: 2013-06-11 Last updated: 2017-12-06
Yuan, D., Angelakis, V., Chen, L., Karipidis, E. & Larsson, E. G. (2013). On Optimal Link Activation with Interference Cancelation in Wireless Networking. IEEE Transactions on Vehicular Technology, 62(2), 939-945
Open this publication in new window or tab >>On Optimal Link Activation with Interference Cancelation in Wireless Networking
Show others...
2013 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, no 2, p. 939-945Article in journal (Refereed) Published
Abstract [en]

A fundamental aspect in performance engineering of wireless networks is optimizing the set of links that can be concurrently activated to meet given signal-to-interference-and-noise ratio (SINR) thresholds. The solution of this combinatorial problem is the key element in scheduling and cross-layer resource management. In this paper, we assume multiuser decoding receivers, which can cancel strongly interfering signals. As a result, in contrast to classical spatial reuse, links being close to each other are more likely to be active concurrently. Our focus is to gauge the gain of successive interference cancellation (SIC), as well as the simpler, yet instructive, case of parallel interference cancellation (PIC), in the context of optimal link activation. We show that both problems are NP-hard and develop compact integer linear programming formulations that enable to approach global optimality. We provide an extensive numerical performance evaluation, indicating that for low to medium SINR thresholds the improvement is quite substantial, especially with SIC, whereas for high SINR thresholds the improvement diminishes and both schemes perform equally well.

Keywords
Integer linear programming, interference cancellation, link activation, multiuser decoding, optimization, wireless networks
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-81933 (URN)10.1109/TVT.2012.2222683 (DOI)000318515100045 ()
Available from: 2012-09-25 Created: 2012-09-25 Last updated: 2017-12-07
Litjens, R., Zhang, H., Noppen, I., Yu, L., Karipidis, E. & Börner, K. (2013). System-level Assessment of Non-Orthogonal Spectrum Sharing via Transmit Beamforming. In: Proceedings of the 77th IEEE Vehicular Technology Conference (VTC-spring): . Paper presented at Proceedings of the 77th IEEE Vehicular Technology Conference (VTC-spring) (pp. 1-6).
Open this publication in new window or tab >>System-level Assessment of Non-Orthogonal Spectrum Sharing via Transmit Beamforming
Show others...
2013 (English)In: Proceedings of the 77th IEEE Vehicular Technology Conference (VTC-spring), 2013, p. 1-6Conference paper, Oral presentation only (Refereed)
Abstract [en]

We assess the system-level performance of non-orthogonal spectrum sharing achieved via maximum sum-rate (SR), Nash bargaining (NB), and zero-forcing (ZF) transmit beamforming techniques. A look-up table based physical layer abstraction and radio resource management mechanisms (including packet scheduling) are proposed and incorporated in system-level simulations, jointly with other important aspects of network operation. In the simulated scenarios, the results show similar system-level performance of SR (or NB) as ZF in the context of spectrum sharing, when combined with maximum sum-rate (or proportional fair) packet scheduler. Further sensitivity analysis also shows similar behavior of all three beamforming techniques with regard to the impact on system-level performance of neighbor-cell activity level and feedback error. A more important observation from our results is that, under ideal conditions, the performance enhancement of non-orthogonal spectrum sharing over orthogonal spectrum sharing and fixed spectrum assignment is significant.

National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-87190 (URN)10.1109/VTCSpring.2013.6692778 (DOI)978-146736337-2 (ISBN)
Conference
Proceedings of the 77th IEEE Vehicular Technology Conference (VTC-spring)
Funder
EU, FP7, Seventh Framework Programme, 248001
Available from: 2013-01-14 Created: 2013-01-14 Last updated: 2014-11-27
Anchora, L., Badia, L., Karipidis, E. & Zorzi, M. (2012). Capacity Gains due to Orthogonal Spectrum Sharing in Multi-Operator LTE Cellular Networks. In: Proceedings of the Ninth International Symposium on Wireless Communication Systems (ISWCS): . Paper presented at The Ninth International Symposium on Wireless Communication Systems (ISWCS), Aug. 28-31, 2012, Paris, France (pp. 286-290).
Open this publication in new window or tab >>Capacity Gains due to Orthogonal Spectrum Sharing in Multi-Operator LTE Cellular Networks
2012 (English)In: Proceedings of the Ninth International Symposium on Wireless Communication Systems (ISWCS), 2012, p. 286-290Conference paper, Published paper (Refereed)
Abstract [en]

Static spectrum allocation leads to resource wastage and inter-operator spectrum sharing is a possible way to improve spectrum efficiency. In this work, we assume that two cellular network operators agree upon sharing part of their spectrum, which can then be dynamically accessed by either of them in a mutually exclusive way. Our goal is to numerically assess the gain, in terms of cell capacity, due to such orthogonal spectrum sharing. Hence, we propose a centralized algorithm that performs coordinated scheduling, in order to numerically evaluate an upper bound on the achievable sum capacity. The algorithm is centralized and exploits complete information on both networks to perform the optimum allocation. The simulation results illustrate the impact of the multiuser diversity and the asymmetry in the traffic load among the networks on the overall achievable gain.

National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-77892 (URN)10.1109/ISWCS.2012.6328375 (DOI)978-1-4673-0760-4 (ISBN)978-1-4673-0761-1 (ISBN)
Conference
The Ninth International Symposium on Wireless Communication Systems (ISWCS), Aug. 28-31, 2012, Paris, France
Funder
EU, FP7, Seventh Framework Programme, 248001
Available from: 2012-05-31 Created: 2012-05-31 Last updated: 2014-11-04
Yu, L., Karipidis, E. & Larsson, E. G. (2012). Coordinated scheduling and beamforming for multicell spectrum sharing networks using branch & bound. In: Signal Processing Conference (EUSIPCO), 2012. Paper presented at 20th European Signal Processing Conference (EUSIPCO 2012), 27-31 August 2012, Bucharest, Romania (pp. 819-823). IEEE COMPUTER SOC
Open this publication in new window or tab >>Coordinated scheduling and beamforming for multicell spectrum sharing networks using branch & bound
2012 (English)In: Signal Processing Conference (EUSIPCO), 2012, IEEE COMPUTER SOC , 2012, p. 819-823Conference paper, Published paper (Refereed)
Abstract [en]

We consider the downlink of a multicell network where neighboring multi-antenna base stations share the spectrum and coordinate their frequency and spatial resource allocation strategies to improve the overall network performance. The objective of the coordination is to maximize the number of users that can be scheduled, meeting their quality-of-service requirements with the minimum total transmit power. The coordinated scheduling and multiuser transmit beamforming problem is combinatorial; we formulate it as a mixed-integer second-order cone program and propose a branch and bound algorithm that yields the optimal solution with relatively low-complexity. The algorithm can be used to motivate or benchmark approximation methods and to numerically evaluate the gains due to spectrum sharing and coordination.

Place, publisher, year, edition, pages
IEEE COMPUTER SOC, 2012
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-87989 (URN)000310623800165 ()978-1-4673-1068-0 (ISBN)
Conference
20th European Signal Processing Conference (EUSIPCO 2012), 27-31 August 2012, Bucharest, Romania
Available from: 2013-01-28 Created: 2013-01-28 Last updated: 2016-08-31
Fathi, M. & Karipidis, E. (2012). Distributed Resource Optimization in Multicell OFDMA Networks. In: Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC): . Paper presented at IEEE Wireless Communications and Networking Conference (WCNC) (pp. 1316-1320). IEEE
Open this publication in new window or tab >>Distributed Resource Optimization in Multicell OFDMA Networks
2012 (English)In: Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), IEEE , 2012, p. 1316-1320Conference paper, Published paper (Refereed)
Abstract [en]

We consider the joint allocation of receiver, bit, and power to subcarriers in the downlink of multicell orthogonal frequency-division multiple-access (OFDMA) networks. Assuming that the cells share the entire bandwidth and that the rates are discrete, we formulate the joint allocation problem as a nonlinear mixed integer program (MIP), which however has exponential worst-case complexity. We capitalize on the capability of the receivers to measure the interference-plus-noise on every subcarrier and decompose the joint problem into a set of smaller-scale linear MIPs solved by individual base stations. Accordingly, we propose a distributed algorithm with linear complexity, in which the base stations participate in the problem solution in a round-robin manner. Simulation results demonstrate the effectiveness of the proposed algorithm in comparison with the iterative waterfilling algorithm and the successive optimal solution, by means of standard branch-and-cut solvers, of the individual MIPs.

Place, publisher, year, edition, pages
IEEE, 2012
Series
Wireless Communications and Networking Conference (WCNC), ISSN 1525-3511
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-72918 (URN)10.1109/WCNC.2012.6213982 (DOI)978-1-4673-0436-8 (ISBN)
Conference
IEEE Wireless Communications and Networking Conference (WCNC)
Funder
EU, FP7, Seventh Framework Programme, 248001
Available from: 2011-12-10 Created: 2011-12-10 Last updated: 2014-11-13
Organisations

Search in DiVA

Show all publications