liu.seSök publikationer i DiVA
Ändra sökning
Avgränsa sökresultatet
1 - 20 av 20
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Angelakis, Vangelis
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    A Fully Decentralized and Load-Adaptive Fractional Frequency Reuse Scheme2011Ingår i: Modeling, Analysis & Simulation of Computer and Telecommunication Systems (MASCOTS), 2011 IEEE 19th International Symposium on, 2011, s. 425-428Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new fully decentralized dynamic fractional frequency reuse (FFR)-based scheme for cellular OFDMA networks is introduced. FFR is a technique to mitigate inter-cell interference to improve the throughput of interference-limited users on the cell edge, to the expense of the rest of the cell's users and the aggregate throughput. The proposed scheme aims to limit the FFR-incurred loss of the center users' throughput, while still providing sufficient bandwidth for the cell edge users' communication. This is done by local information sharing and distributed optimization. The resulting flexibility of frequency reuse can be especially beneficial in scenarios with non-uniform and time-varying load. The optimization task is accomplished by solving a knapsack problem in each cell, where the goal is to maximize the center throughput while maintaining acceptable degradation on the cell edge with respect to the original FFR allocation. The performance improvement resulting from the distributed and dynamic FFR scheme is demonstrated by snapshot simulations on an 81-cells network with asymmetric cell load. The proposed scheme achieves up to a 62% gain in cell-center throughput with a cost of no more than 18% at the edges when compared to the classic FFR scheme. The overall system throughput improvement ranges from 22% to 58%.

  • 2.
    Angelakis, Vangelis
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Optimal and Collaborative Rate Selection for Interference Cancellation in Wireless Networks2011Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 15, nr 8, s. 819-821Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Analysis of wireless systems commonly assumes single-user detection at the receivers. Interference is typically treated as noise. On the other hand, multiuser detection has long been taking advantage of interference cancellation (IC) to increase capacity. We exploit IC by optimal rate selection. Transmission rates are collaboratively optimized to maximize the benefit of IC. A link reduces its rate, if that enables IC to significantly boost the SINR on other links. We provide a complexity analysis and an integer programming model to find the optimal IC pattern. Simulation results indicate that throughput improvement is over 30% in low SINR regimes.

  • 3.
    Capone, Antonio
    et al.
    Politecn Milan.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Gualandi, Stefano
    Politecn Milan.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    A New Computational Approach for Maximum Link Activation in Wireless Networks under the SINR Model2011Ingår i: IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, ISSN 1536-1276, Vol. 10, nr 5, s. 1368-1372Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fundamental and computationally challenging optimization task in wireless networks is to maximize the number of simultaneous transmissions, subject to signal-to-noise-and-interference ratio (SINR) requirements at the receivers. The conventional approach guaranteeing global optimality is to solve an integer programming model with explicit SINR constraints. These constraints are however numerically very difficult. We develop a new integer programming algorithm based on a much more effective representation of the SINR constraints. Computational experiments demonstrate that the new approach performs significantly better in proving optimality.

  • 4.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Coverage Planning and Resource Allocation in Broadband Cellular Access: Optimization Models and Algorithms2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The last two decades have witnessed a booming in the use of cellular communication technologies. Billions of people are now enjoying the benefits of mobile communications. This thesis deals with planning and optimization of broadband cellular access network design and operation. The problem types considered include coverage planning, power optimization, and channel assignment. Mathematical modeling and optimization methods have been used to approach the problems.

    Coverage planning is a classical problem in cellular network deployment. A minimum-power covering problem with overlap constraints between cell pairs is considered. The objective is to minimize the total power consumption for coverage, while maintaining a necessary level of overlap to facilitate handover. For this coverage planning problem, the thesis develops two integer programming models and compares the models' strength in approaching global optimality. In addition, a tabu search algorithm has been developed for solving the problem in large-scale networks.

    For High Speed Downlink Packet Access (HSDPA) networks, transmission power is a crucial factor to performance. Minimizing the power allocated for coverage enables significant power saving that can be used for HSDPA data transmission, thus enhancing the HSDPA performance. Exploring this potential power saving, a mathematical model targeting cell-edge HSDPA performance has been developed. In determining the optimal coverage pattern for maximizing power saving, the model also allows for controlling the degree of soft handover for Universal Mobile Telecommunications System (UMTS) Release 99 services. In addition to the mathematical model, heuristic algorithms based on local search and repeated local search are developed.

    For Orthogonal Frequency Division Multiple Access (OFDMA), which is used in Long Term Evolution (LTE) networks, inter-cell interference control is a key performance engineering issue. The aspect is of particular importance to cell-edge throughput. Frequency reuse schemes for mitigating inter-cell interference at cell-edge areas have received an increasing amount of research attention. In the thesis, a generalization of the standard Fractional Frequency Reuse (FFR) scheme is introduced. The generalization addresses OFDMA networks with irregular cell layout.  Optimization algorithms using local search have been proposed to find the frequency reuse pattern of generalized FFR that maximizes the cell-edge area performance.

    For the problems considered in the thesis, computational experiments of the optimization models and algorithms using data sets representing realistic planning scenarios have been carried out. The experimental results demonstrate the effectiveness of the proposed solution approaches.

    Delarbeten
    1. Solving a minimum-power covering problem with overlap constraint for cellular network design
    Öppna denna publikation i ny flik eller fönster >>Solving a minimum-power covering problem with overlap constraint for cellular network design
    2010 (Engelska)Ingår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 203, nr 3, s. 714-723Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We consider a type of covering problem in cellular networks. Given the locations of base stations, the problem amounts to determining cell coverage at minimum cost in terms of the power usage. Overlap between adjacent cells is required in order to support handover. The problem we consider is NP-hard. We present integer linear models and study the strengths of their continuous relaxations. Preprocessing is used to reduce problem size and tighten the models. Moreover, we design a tabu search algorithm for finding near-optimal solutions effectively and time-efficiently. We report computational results for both synthesized instances and networks originating from real planning scenarios. The results show that one of the integer models leads to tight bounds, and the tabu search algorithm generates high-quality solutions for large instances in short computing time.

    Nyckelord
    OR in telecommunications; Cellular networks; Covering; Integer programming; Tabu search
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-52895 (URN)10.1016/j.ejor.2009.09.018 (DOI)
    Anmärkning
    Original Publication: Lei Chen and Di Yuan, Solving a minimum-power covering problem with overlap constraint for cellular network design, 2010, European Journal of Operational Research, (203), 3, 714-723. http://dx.doi.org/10.1016/j.ejor.2009.09.018 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/Tillgänglig från: 2010-01-13 Skapad: 2010-01-12 Senast uppdaterad: 2017-12-12
    2. Coverage Planning for Optimizing HSDPA Performance and Controlling R99 Soft Handover
    Öppna denna publikation i ny flik eller fönster >>Coverage Planning for Optimizing HSDPA Performance and Controlling R99 Soft Handover
    2012 (Engelska)Ingår i: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 51, nr 1, s. 53-64Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Coverage planning is an important engineering task in deploying UMTSnetworks implementing both high speed downlink packet access (HSDPA)and Release 99 (R99) services.  Coverage planning amounts todetermining the cell coverage pattern by means of setting the commonpilot channel (CPICH) power of the cells. A conventional strategy isto uniformly allocate a proportion of the total power to CPICH. Inthis paper, we develop mathematical modeling and optimizationapproaches to bring the benefit of power saving enabled by optimizingnon-uniform CPICH to enhance HSDPA performance, while preserving adesired degree of soft handover (SHO) for R99.  The studyfocuses on HSDPA performance at cell edges, where data throughput istypically low.  An integer linear programming model is developed forthe resulting optimization problem.  The model admits optimal ornear-optimal planning solutions for relatively small networks.Solution algorithms based on local search and repeated localsearch are developed.  These algorithms are able to perform theoptimization for large-scale networks time-efficiently.  Experimentalresults for both synthesized networks as well as instances originatingfrom real planning scenarios demonstrate the benefit of ouroptimization approach.

    Ort, förlag, år, upplaga, sidor
    Springer, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-62761 (URN)10.1007/s11235-010-9414-z (DOI)000311517300006 ()
    Anmärkning

    funding agencies|CENIIT||Linkoping Institute of Technology, Sweden||Swedish Research Council (Vetenskapsradet)||ELLIIT network||

    Tillgänglig från: 2010-12-03 Skapad: 2010-12-03 Senast uppdaterad: 2017-12-12
    3. Generalizing and Optimizing Fractional Frequency Reuse in Broadband Cellular Radio Access Networks
    Öppna denna publikation i ny flik eller fönster >>Generalizing and Optimizing Fractional Frequency Reuse in Broadband Cellular Radio Access Networks
    2012 (Engelska)Ingår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 230Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    For broadband cellular access based on orthogonal frequency divisionmultiple access (OFDMA), fractional frequency reuse (FFR) is one ofthe key concepts for mitigating inter-cell interference and therebyoptimizing cell-edge performance. In standard FFR, the number of OFDMAsub-bands and the reuse factor are both fixed. Whereas this works wellfor an idealized cell pattern, it is neither directly applicable noradequate for real-life networks with very irregular cell layouts. Inthis paper, we generalize the standard FFR to allow for flexibilities inthe total number of sub-bands as well as the number of sub-bands ineach cell-edge zone, enabling network-adaptive FFR. Two powerassignment strategies that use fixed power per sub-band prior tosub-band allocation and apply cell-specific power derived from thenumber of sub-bands allocated to each cell-edge zone, respectively,are investigated. Optimization algorithms based on local search aredeveloped for sub-band allocation to maximize the cell-edgethroughput. Evaluations using networks with realistic radiopropagation conditions demonstrate the applicability of the generalizedand optimized FFR in performance engineering of OFDMA networks.

    Nyckelord
    orthogonal frequency division multiple access; fractional frequency reuse; optimization; local search.
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-62762 (URN)10.1186/1687-1499-2012-230 (DOI)000315038300001 ()
    Tillgänglig från: 2010-12-03 Skapad: 2010-12-03 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
  • 5.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Performance Engineering of Mobile Broadband: Capacity Analysis, Cellular Network Optimization, and Design of In-Building Solutions2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The rapid evolution of mobile communication technologies is making mobile broadband a reality. With over 6 billion cellular connections and the booming of mobile data, mobile broadband leads the technology and service innovation within the domain of information and communication technologies. The thesis deals with performance engineering of mobile broadband. The problems investigated range from fundamental capacity analysis, resource planning and optimization of broadband cellular networks, to design of in-building solutions based on distributed antenna systems. Mathematical modeling and optimization methods have been used to approach the problems.

    The first three papers address capacity analysis in wireless communications, where the establishment of any communication link is subject to the Signal to Interference plus Noise Ratio (SINR) threshold. Paper I addresses the maximum link activation problem. The paper introduces a new exact algorithm by reformulating the SINR constraints with equivalent but numerically more effective inequalities, leading to an approach performing significantly better in proving optimality in comparison to the conventional algorithm. Paper II explores the notion of collaborative rate selection for Interference Cancellation (IC) to maximize the transmission rate in wireless networks. The paper analyzes the problem complexity and develops integer programming models for both single stage single-link IC and single stage parallel IC. Paper III studies the performance gain of single-stage and multi-stage IC to optimal link activation. Compact integer programming formulations have been developed and a thorough numerical study is performed.

    The next three papers are devoted to planning and optimization of radio resources in cellular mobile broadband networks. Paper IV considers a minimum-power coverage problem with overlap requirements between cell pairs. The paper develops two integer programming models and compares their strength in approaching global optimality. A tabu search algorithm has been developed for large-scale networks. Paper V deals with transmission power planning and optimization in High Speed Downlink Packet Access (HSDPA) networks. A method for enhancing the HSDPA performance by minimizing the power for coverage and reallocating the power to data transmission has been considered. A mathematical model targeting cell-edge HDSPA performance and accounting for soft handover in Universal Mobile Telecommunications System (UMTS) has been developed. In addition, heuristic algorithms based on local search and repeated local search are developed. Paper VI focuses on frequency planning for inter-cell interference mitigation in Orthogonal Frequency Division Multiple Access (OFDMA) networks. The paper generalizes the standard Fractional Frequency Reuse (FFR) concept and addresses its performance for networks with irregular topology. Optimization algorithms using local search have been proposed to find the frequency reuse pattern of generalized FFR for maximizing the edge-user performance. The investigations in Papers IV-VI base the experiments on data sets representing realistic planning scenarios to demonstrate the effectiveness of the proposed approaches.

    To face the challenge of in-building mobile broadband service, In-Building Distributed Antennas Systems (IB-DAS) has been proposed. Paper VII tackles the problem of optimal topology design of IB-DAS systems, where a number of in-building distributed antennas are connected to a base station via coaxial cables and power equipments. The paper develops efficient mathematical models for topology design as well as equipment selection, and presents case studies of realistic IB-DAS deployment scenarios.

    Delarbeten
    1. A New Computational Approach for Maximum Link Activation in Wireless Networks under the SINR Model
    Öppna denna publikation i ny flik eller fönster >>A New Computational Approach for Maximum Link Activation in Wireless Networks under the SINR Model
    2011 (Engelska)Ingår i: IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, ISSN 1536-1276, Vol. 10, nr 5, s. 1368-1372Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A fundamental and computationally challenging optimization task in wireless networks is to maximize the number of simultaneous transmissions, subject to signal-to-noise-and-interference ratio (SINR) requirements at the receivers. The conventional approach guaranteeing global optimality is to solve an integer programming model with explicit SINR constraints. These constraints are however numerically very difficult. We develop a new integer programming algorithm based on a much more effective representation of the SINR constraints. Computational experiments demonstrate that the new approach performs significantly better in proving optimality.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers, 2011
    Nyckelord
    Wireless networks, optimization, link activation, SINR, integer programming
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-68909 (URN)10.1109/TWC.2011.030311.100777 (DOI)000290992300005 ()
    Anmärkning
    ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Antonio Capone, Lei Chen, Stefano Gualandi and Di Yuan, A New Computational Approach for Maximum Link Activation in Wireless Networks under the SINR Model, 2011, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, (10), 5, 1368-1372. http://dx.doi.org/10.1109/TWC.2011.030311.100777Tillgänglig från: 2011-06-10 Skapad: 2011-06-10 Senast uppdaterad: 2013-03-04
    2. Optimal and Collaborative Rate Selection for Interference Cancellation in Wireless Networks
    Öppna denna publikation i ny flik eller fönster >>Optimal and Collaborative Rate Selection for Interference Cancellation in Wireless Networks
    2011 (Engelska)Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 15, nr 8, s. 819-821Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Analysis of wireless systems commonly assumes single-user detection at the receivers. Interference is typically treated as noise. On the other hand, multiuser detection has long been taking advantage of interference cancellation (IC) to increase capacity. We exploit IC by optimal rate selection. Transmission rates are collaboratively optimized to maximize the benefit of IC. A link reduces its rate, if that enables IC to significantly boost the SINR on other links. We provide a complexity analysis and an integer programming model to find the optimal IC pattern. Simulation results indicate that throughput improvement is over 30% in low SINR regimes.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers (IEEE), 2011
    Nyckelord
    Interference cancellation, rate selection, optimization, wireless communications
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-70529 (URN)10.1109/LCOMM.2011.062711.110561 (DOI)000294133000012 ()
    Tillgänglig från: 2011-09-12 Skapad: 2011-09-12 Senast uppdaterad: 2017-12-08
    3. On Optimal Link Activation with Interference Cancelation in Wireless Networking
    Öppna denna publikation i ny flik eller fönster >>On Optimal Link Activation with Interference Cancelation in Wireless Networking
    Visa övriga...
    2013 (Engelska)Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, nr 2, s. 939-945Artikel i tidskrift (Refereegranskat) 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.

    Nyckelord
    Integer linear programming, interference cancellation, link activation, multiuser decoding, optimization, wireless networks
    Nationell ämneskategori
    Kommunikationssystem
    Identifikatorer
    urn:nbn:se:liu:diva-81933 (URN)10.1109/TVT.2012.2222683 (DOI)000318515100045 ()
    Tillgänglig från: 2012-09-25 Skapad: 2012-09-25 Senast uppdaterad: 2017-12-07
    4. Solving a minimum-power covering problem with overlap constraint for cellular network design
    Öppna denna publikation i ny flik eller fönster >>Solving a minimum-power covering problem with overlap constraint for cellular network design
    2010 (Engelska)Ingår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 203, nr 3, s. 714-723Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We consider a type of covering problem in cellular networks. Given the locations of base stations, the problem amounts to determining cell coverage at minimum cost in terms of the power usage. Overlap between adjacent cells is required in order to support handover. The problem we consider is NP-hard. We present integer linear models and study the strengths of their continuous relaxations. Preprocessing is used to reduce problem size and tighten the models. Moreover, we design a tabu search algorithm for finding near-optimal solutions effectively and time-efficiently. We report computational results for both synthesized instances and networks originating from real planning scenarios. The results show that one of the integer models leads to tight bounds, and the tabu search algorithm generates high-quality solutions for large instances in short computing time.

    Nyckelord
    OR in telecommunications; Cellular networks; Covering; Integer programming; Tabu search
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-52895 (URN)10.1016/j.ejor.2009.09.018 (DOI)
    Anmärkning
    Original Publication: Lei Chen and Di Yuan, Solving a minimum-power covering problem with overlap constraint for cellular network design, 2010, European Journal of Operational Research, (203), 3, 714-723. http://dx.doi.org/10.1016/j.ejor.2009.09.018 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/Tillgänglig från: 2010-01-13 Skapad: 2010-01-12 Senast uppdaterad: 2017-12-12
    5. Coverage Planning for Optimizing HSDPA Performance and Controlling R99 Soft Handover
    Öppna denna publikation i ny flik eller fönster >>Coverage Planning for Optimizing HSDPA Performance and Controlling R99 Soft Handover
    2012 (Engelska)Ingår i: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 51, nr 1, s. 53-64Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Coverage planning is an important engineering task in deploying UMTSnetworks implementing both high speed downlink packet access (HSDPA)and Release 99 (R99) services.  Coverage planning amounts todetermining the cell coverage pattern by means of setting the commonpilot channel (CPICH) power of the cells. A conventional strategy isto uniformly allocate a proportion of the total power to CPICH. Inthis paper, we develop mathematical modeling and optimizationapproaches to bring the benefit of power saving enabled by optimizingnon-uniform CPICH to enhance HSDPA performance, while preserving adesired degree of soft handover (SHO) for R99.  The studyfocuses on HSDPA performance at cell edges, where data throughput istypically low.  An integer linear programming model is developed forthe resulting optimization problem.  The model admits optimal ornear-optimal planning solutions for relatively small networks.Solution algorithms based on local search and repeated localsearch are developed.  These algorithms are able to perform theoptimization for large-scale networks time-efficiently.  Experimentalresults for both synthesized networks as well as instances originatingfrom real planning scenarios demonstrate the benefit of ouroptimization approach.

    Ort, förlag, år, upplaga, sidor
    Springer, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-62761 (URN)10.1007/s11235-010-9414-z (DOI)000311517300006 ()
    Anmärkning

    funding agencies|CENIIT||Linkoping Institute of Technology, Sweden||Swedish Research Council (Vetenskapsradet)||ELLIIT network||

    Tillgänglig från: 2010-12-03 Skapad: 2010-12-03 Senast uppdaterad: 2017-12-12
    6. Generalizing and Optimizing Fractional Frequency Reuse in Broadband Cellular Radio Access Networks
    Öppna denna publikation i ny flik eller fönster >>Generalizing and Optimizing Fractional Frequency Reuse in Broadband Cellular Radio Access Networks
    2012 (Engelska)Ingår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 230Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    For broadband cellular access based on orthogonal frequency divisionmultiple access (OFDMA), fractional frequency reuse (FFR) is one ofthe key concepts for mitigating inter-cell interference and therebyoptimizing cell-edge performance. In standard FFR, the number of OFDMAsub-bands and the reuse factor are both fixed. Whereas this works wellfor an idealized cell pattern, it is neither directly applicable noradequate for real-life networks with very irregular cell layouts. Inthis paper, we generalize the standard FFR to allow for flexibilities inthe total number of sub-bands as well as the number of sub-bands ineach cell-edge zone, enabling network-adaptive FFR. Two powerassignment strategies that use fixed power per sub-band prior tosub-band allocation and apply cell-specific power derived from thenumber of sub-bands allocated to each cell-edge zone, respectively,are investigated. Optimization algorithms based on local search aredeveloped for sub-band allocation to maximize the cell-edgethroughput. Evaluations using networks with realistic radiopropagation conditions demonstrate the applicability of the generalizedand optimized FFR in performance engineering of OFDMA networks.

    Nyckelord
    orthogonal frequency division multiple access; fractional frequency reuse; optimization; local search.
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-62762 (URN)10.1186/1687-1499-2012-230 (DOI)000315038300001 ()
    Tillgänglig från: 2010-12-03 Skapad: 2010-12-03 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
    7. Mathematical Modeling for Optimal Design of In-Building Distributed Antenna Systems
    Öppna denna publikation i ny flik eller fönster >>Mathematical Modeling for Optimal Design of In-Building Distributed Antenna Systems
    2013 (Engelska)Ingår i: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 57, nr 17, s. 3428-3445Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In-building Distributed Antenna System (IB-DAS) has proven to be one of the most promising In-Building Solutions (IBS) to provide coverage and capacity for indoor users. We consider optimal deployment of the passive IB-DAS, focusing on mathematical optimization models based on integer programming, for the topology design and optimal equipment selection of IB-DAS. The models minimize the cable cost and keep the transmit power at each antenna within a pre-defined interval, thus guaranteeing the quality of service. The models can deliver optimal solutions to systems of which the size is of practical relevance. To improve the time efficiency, we develop preprocessing techniques that integrate the building layout data into the system modeling. Application of the models to realistic IB-DAS deployment demonstrates the effectiveness of the models.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2013
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-89716 (URN)10.1016/j.comnet.2013.07.027 (DOI)000328295600012 ()
    Tillgänglig från: 2013-03-04 Skapad: 2013-03-04 Senast uppdaterad: 2017-12-06
  • 6.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Song, Hui
    Ranplan Wireless Network Design, Ltd, UK.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Zhang, Jie
    University of Sheffield, UK.
    Mathematical Modeling for Optimal Deployment of In-Building Distributed Antenna Systems2012Ingår i: Communications in China (ICCC), 2012, IEEE , 2012, s. 786-791Konferensbidrag (Refereegranskat)
    Abstract [en]

    In-building Distributed Antenna System (IB-DAS) has been proved to be one of the most efficient methods to provide sufficient coverage and capacity for indoor users. The target of a successful IB-DAS deployment is to guarantee the coverage as well as the capacity of the in-building areas with minimum deployment cost. We consider the optimaldeployment of the IB-DAS based on passive DAS in this paper. Mixed Integer Programming model has been developed forthe topology design of IB-DAS through the optimal installation of power splitters in order to connect all the antennas with minimum cable cost, meanwhile, the transmit power at each antenna are kept within the satisfied level for the service guarantee. The model can deliver optimal solutions to systems with a practical size where passive DAS is commonly deployed. To improve the time efficiency, preprocessing has been done to integrate the building layout data into themodeling. Application of the model over realistic IB-DAS deployment has been conducted, which demonstrates the effectiveness of the model.

  • 7.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Achieving higher HSDPA performance and preserving R99 soft handover control by large scale optimization in CPICH coverage planning2009Ingår i: Proceedings of IEEE Wireless Telecommunications Symposium (WTS) 2009, Piscataway, NJ, USA: IEEE , 2009, s. 39-44Konferensbidrag (Refereegranskat)
    Abstract [en]

    Common Pilot Channel (CPICH) power is a crucial parameter in coverage planning of todays UMTS networks that implement both HSDPA and R99 services. Adopting a non-uniform allocation of cell CPICH power and minimizing its amount necessary for coverage, the resulting power saving significantly improves HSDPA performance. At the same time, it is vital to have the desired level R99 soft handover which is heavily influenced by CPICH. In this paper, we demonstrate how large scale optimization can deal with both tasks. Our approach focuses on enhancing cell-edge HSDPA data rate, subject to requirements of CPICH coverage and the level of R99 soft(-er) handover We present a solution algorithm that optimizes CPICH allocation for HSDPA performance, and, in parallel, offers accurate control of R99 soft handover Experimental results for large and realistic network planning scenarios demonstrate the benefit of our optimization approach.

  • 8.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Automated Planning of CPICH Power for enhancing HSDPA Performance at Cell Edges with Preserved Control of R99 Soft Handover2008Ingår i: IEEE International Conference on Communications, 2008. ICC '08., Piscataway, NJ, USA: IEEE , 2008, s. 2936-2940Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present and demonstrate a novel approach for automated planning of common pilot channel (CPICH) power in mobile networks with co-existing HSDPA and R99 services. CPICH power allocation greatly influences the cell coverage pattern. A conventional strategy is to uniformly allocate a constant proportion of the total power to CPICH. We study non-uniform CPICH and optimize its allocation for enhancing HSDPA performance. We focus on HSDPA performance at cell edges, where user throughput is typically very low. Our approach is based on a linear-integer mathematical model; solving the model results in a power allocation that both ensures CPICH coverage and optimizes HSDPA performance at cell edges. Moreover, the model allows for precise control of soft handover (SHO) regions for R99 service. Experimental results show that our approach yields significant enhancement of HSDPA performance at cell edges with preserved R99 SHO control.

  • 9.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Beyond Conventional Fractional Frequency Reuse for Networks with Irregular Cell Layout: An Optimization Approach and Performance Evaluation2010Ingår i: Proceedings of the 5th Annual International Wireless Internet Conference (WICON), IEEE , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fractional frequency reuse (FFR) is one of the key concepts for interference mitigation in OFDMA networks. Previous work on FFR has focused on networks of relatively small size and standard hexagon-shaped cell layout. For real-life networks with very irregular cell layout and high variation in radio propagation, standard reuse schemes (e.g., reuse with a factor three) are inadequate; applying a standard scheme, if possible at all, is far from optimal due to the irregularity. We present an approach based on large-scale optimization to study FFR in networks with irregular cell layout. The approach goes beyond the conventional reuse schemes by optimizing the allocation of the cell-edge sub-band of every cell, taking into account the interference caused by the sub-band allocation of all other cells. What's more, whereas the conventional FFR scheme uses three sub-bands, our optimization process allows for considering the number of subbands as a parameter, and enables the analysis of the impact of this parameter on FFR performance. Performance evaluation for networks with realistic radio propagation conditions shows that the approach enables significant throughput improvement at cell-edge zones, and sometimes it is optimal to split the cell-edge band into more than the standard three sub-bands. These results along with the analysis demonstrate the potential benefits of the proposed approach in practicing FFR for large-scale networks, and illustrate the performance trade-off between the cell-edge and cell-center zones.

  • 10.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Coverage Planning for Optimizing HSDPA Performance and Controlling R99 Soft Handover2012Ingår i: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 51, nr 1, s. 53-64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coverage planning is an important engineering task in deploying UMTSnetworks implementing both high speed downlink packet access (HSDPA)and Release 99 (R99) services.  Coverage planning amounts todetermining the cell coverage pattern by means of setting the commonpilot channel (CPICH) power of the cells. A conventional strategy isto uniformly allocate a proportion of the total power to CPICH. Inthis paper, we develop mathematical modeling and optimizationapproaches to bring the benefit of power saving enabled by optimizingnon-uniform CPICH to enhance HSDPA performance, while preserving adesired degree of soft handover (SHO) for R99.  The studyfocuses on HSDPA performance at cell edges, where data throughput istypically low.  An integer linear programming model is developed forthe resulting optimization problem.  The model admits optimal ornear-optimal planning solutions for relatively small networks.Solution algorithms based on local search and repeated localsearch are developed.  These algorithms are able to perform theoptimization for large-scale networks time-efficiently.  Experimentalresults for both synthesized networks as well as instances originatingfrom real planning scenarios demonstrate the benefit of ouroptimization approach.

  • 11.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    CPICH Power Planning for Optimizing HSDPA and R99 SHO Performance: Mathematical Modelling and Solution Approach2008Ingår i: 1st IFIP Wireless Days, 2008. WD '08., Piscataway, NJ, USA: IEEE , 2008, s. 1-5Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present and demonstrate mathematical modelling and optimization algorithm for enhancing HSDPA performance by automatically linking Common Pilot Channel (CPICH) power to HSDPA transmit power. Our approach uses non-uniformly allocated CPICH power and focuses on HSDPA performance with the side constraint of R99 soft handover. Solving the mathematical model gives the optimal CPICH allocation for small networks. The optimization algorithm demonstrates itself very time efficient in dealing with large scale networks which might have hundreds of cells and tens of thousands of users. A case study of realistic network planning scenario for Berlin shows significant CPICH power saving and HSDPA performance improvement.

  • 12.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Enhanced Fractional Frequency Reuse for large-scale OFDMA networks with heterogeneous cell layout: Optimization and performance evaluation2010Ingår i: Communication Systems (ICCS), 2010, IEEE , 2010, s. 279-283Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fractional Frequency Reuse (FFR) is one of the key concepts for mitigating inter-cell interference and improving cell-edge performance in OFDMA networks. The standard FFR scheme is intuitive and optimal for the hexagon-shaped cell pattern. In contrast, real-life OFDMA systems have very irregular cell layout, thus the number of surrounding cells and their respective interference vary significantly over the network. For such scenarios, the standard scheme, if applicable at all, is inadequate because the number of sub-bands and the reuse factor are fixed. To overcome the limitations, we present enhanced FFR (EFFR) that allows for high flexibility in the total number of sub-bands as well as the allocation of sub-bands in edge zones. An optimization algorithm is developed to determine sub-band allocation to maximize the cell-edge throughput. Hence EFFR adapts the allocation and reuse pattern to the irregularity of each individual network. Evaluations based on networks with realistic radio propagation conditions show the high performance of EFFR in improving cell-edge throughput. The improvement allows for better trade-off between cell-center and cell-edge throughput. These results along with the analysis demonstrate the benefits of EFFR to performance engineering of OFDMA networks.

  • 13.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Fast Algorithm for Large-scale UMTS Coverage Planning with Soft Handover Consideration2009Ingår i: Proceedings of the 2009 International Conference on Wireless Communications and Mobile Computing: Connecting the World Wirelessly, New York, NY, USA: ACM , 2009, s. 1488-1492Konferensbidrag (Refereegranskat)
    Abstract [en]

    Coverage planning by means of controlling cell Common Pilot Channel (CPICH) power is an important task in deploying UMTS networks. In addition to determining coverage, CPICH power heavily influences the amount of Soft Handover (SHO). Non-uniform cell CPICH power allows for significant power saving and thereby higher capacity for traffic channels. However, optimizing non-uniform CPICH is challenging in terms of computational effort, if the resulting coverage pattern is required to satisfy a desired level of SHO. We present a very fast algorithm for this planning problem. The algorithm has utilized the fact that SHO is strongly correlated with cell overlap. Using overlap as a very good approximation of SHO, the algorithm can compute a near optimal coverage pattern within a few seconds even for large networks. Next, the solution is further polished to deal with SHO accurately. Simulation results show that our solution strategy is able to perform non-uniform CPICH optimization very time-efficiently, making it possible to tackle large scale UMTS coverage planning under SHO consideration.

  • 14.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Generalized Frequency Reuse Schemes for OFDMA Networks: Optimization and Comparison2010Ingår i: IEEE 71st Vehicular Technology Conference (VTC 2010-Spring), 2010, Piscataway, NJ, USA: IEEE , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Frequency reuse is a key concept for interference mitigation and thereby enhancing cell-edge performance in OFDMA networks. Two representative strategies are Fractional Frequency Reuse (FFR) and Soft Frequency Reuse (SFR). Both divide a cell into a center zone and an edge zone, and differentiate their levels of frequency reuse. Previous work on FFR and SFR has focused on networks of relatively small size with standard hexagon-shaped cells. And dividing the cell edge frequency band into three parts has been a common practice so far. However, for real-life networks, this is inadequate because of the irregular cell layout. We consider generalized FFR and SFR schemes, where the number of sub-bands is not restricted to three, and for SFR the power ratio is variable. To find optimal sub- band allocation for the generalized schemes, we present an approach based on large-scale optimization to deal with networks with irregular cell layout. The optimization process allows us to analyze the impact of the number of sub-bands and the SFR power ratio on cell-edge performance, and thereby compare the reuse schemes. We conduct experiments on large networks with realistic radio propagations and present a thorough numerical comparison.

  • 15.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Generalizing and Optimizing Fractional Frequency Reuse in Broadband Cellular Radio Access Networks2012Ingår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For broadband cellular access based on orthogonal frequency divisionmultiple access (OFDMA), fractional frequency reuse (FFR) is one ofthe key concepts for mitigating inter-cell interference and therebyoptimizing cell-edge performance. In standard FFR, the number of OFDMAsub-bands and the reuse factor are both fixed. Whereas this works wellfor an idealized cell pattern, it is neither directly applicable noradequate for real-life networks with very irregular cell layouts. Inthis paper, we generalize the standard FFR to allow for flexibilities inthe total number of sub-bands as well as the number of sub-bands ineach cell-edge zone, enabling network-adaptive FFR. Two powerassignment strategies that use fixed power per sub-band prior tosub-band allocation and apply cell-specific power derived from thenumber of sub-bands allocated to each cell-edge zone, respectively,are investigated. Optimization algorithms based on local search aredeveloped for sub-band allocation to maximize the cell-edgethroughput. Evaluations using networks with realistic radiopropagation conditions demonstrate the applicability of the generalizedand optimized FFR in performance engineering of OFDMA networks.

  • 16.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Generalizing FFR by Flexible Sub-Band Allocation in OFDMA Networks with Irregular Cell Layout2010Ingår i: IEEE Wireless Communications and Networking Conference Workshops (WCNCW), 2010, IEEE , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fractional Frequency Reuse (FFR) is one of the key concepts for enhancing cell-edge performance of OFDMA networks. Standard FFR allows one sub-band to be allocated for each cell. This limits the performance improvement of cell edge users, especially those bandwidth-sensitive users. With flexible sub-band allocation, cell edge can be allocated more than one sub-band, thereby performance can be improved largely. Furthermore, previous work on FFR has focused on networks of relatively small size and with standard hexagon- shaped cells.For real-life networks with a very irregular cell layout, these results are inadequate. In this paper, we present the idea of Flexible FFR (FFR-F) which allows more than one sub-band to be allocated to cell edges. Meanwhile, an optimization algorithm based on local search is present for FFR-F planning in large-scale networks with irregular cell layout. Sub-band allocation scheme which maximizes the cell-edge throughput can be found time efficiently. Results from networks with realistic radio propagation conditions show that FFR-F enables significant throughput improvement at cell edges. These results along with the analysis demonstrate the potential benefits of FFR-F and the proposed approach for planning of real-life OFDMA networks.

  • 17.
    Chen, Lei
    et al.
    Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan.
    Mathematical Modeling for Optimal Design of In-Building Distributed Antenna Systems2013Ingår i: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 57, nr 17, s. 3428-3445Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In-building Distributed Antenna System (IB-DAS) has proven to be one of the most promising In-Building Solutions (IBS) to provide coverage and capacity for indoor users. We consider optimal deployment of the passive IB-DAS, focusing on mathematical optimization models based on integer programming, for the topology design and optimal equipment selection of IB-DAS. The models minimize the cable cost and keep the transmit power at each antenna within a pre-defined interval, thus guaranteeing the quality of service. The models can deliver optimal solutions to systems of which the size is of practical relevance. To improve the time efficiency, we develop preprocessing techniques that integrate the building layout data into the system modeling. Application of the models to realistic IB-DAS deployment demonstrates the effectiveness of the models.

  • 18.
    Chen, Lei
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Performance Evaluation of Soft Frequency Reuse in Large Networks with  Irregular Cell Pattern: How Much Gain To Expect?2009Ingår i: Proceedings of IEEE PIMRC 2009, 2009Konferensbidrag (Refereegranskat)
  • 19.
    Chen, Lei
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Solving a minimum-power covering problem with overlap constraint for cellular network design2010Ingår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 203, nr 3, s. 714-723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We consider a type of covering problem in cellular networks. Given the locations of base stations, the problem amounts to determining cell coverage at minimum cost in terms of the power usage. Overlap between adjacent cells is required in order to support handover. The problem we consider is NP-hard. We present integer linear models and study the strengths of their continuous relaxations. Preprocessing is used to reduce problem size and tighten the models. Moreover, we design a tabu search algorithm for finding near-optimal solutions effectively and time-efficiently. We report computational results for both synthesized instances and networks originating from real planning scenarios. The results show that one of the integer models leads to tight bounds, and the tabu search algorithm generates high-quality solutions for large instances in short computing time.

  • 20.
    Yuan, Di
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Angelakis, Vangelis
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Chen, Lei
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Karipidis, Eleftherios
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Larsson, Erik G.
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    On Optimal Link Activation with Interference Cancelation in Wireless Networking2013Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, nr 2, s. 939-945Artikel i tidskrift (Refereegranskat)
    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.

1 - 20 av 20
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf