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  • 1.
    Siomina, Iana
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    A novel approach for mobility models in an inhomogeneous area2005Inngår i: 16th Annual IEEE International Symposium on Personal Indoor and Mobile Radio Communications PIMRC 2005,2005, Berlin, Germany: VDE VERLAG GMBH , 2005Konferansepaper (Fagfellevurdert)
  • 2.
    Siomina, Iana
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    P-CPICH power and antenna tilt optimization in UMTS networks2005Inngår i: Advanced Industrial Conference on Telecommunications,2005, Los Alamitos, California: IEEE Computer Society , 2005, s. 268-Konferansepaper (Fagfellevurdert)
  • 3.
    Siomina, Iana
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Pilot power management in radio network planning for WCDMA networks2005Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The high price of auction-based 3G licences and the growing competition in telecommunications market is putting enormous pressure on manufacturers and operators to configure the next-generation mobile network in the most cost-effective way possible providing high quality 3G services. Therefore, aiming to improve overall network performance and to ensure efficient utilization of network resources, radio network planning and optimization became even more important thar. in previous generation networks. On the other hand, in 3G networks, due to support of multiple services, high data rates, low frequency reuse, higher spectral loading and interference levels, and much uncertainty about future traffic growth. these processes became more challenging tasks.

    This thesis addresses the problem of pilot power optimization in WCDMA (Wideband Code Division Multiple Access) networks studying such issues as a trade-off between coverage of the service area and pilot power consumption, load balancing, and soft handover control. In the thesis, the author presents a number of pilot power optimization models, discusses the solution approaches. and reports numerical results obtained for test networks of various sizes based on real planning scenarios.

  • 4.
    Siomina, Iana
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Radio Network Planning and Resource Optimization: Mathematical Models and Algorithms for UMTS, WLANs, and Ad Hoc Networks2007Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The tremendous popularity of wireless technologies during the last decade has created a considerable expansion of wireless networks both in size and use. This fact, together with a great variety of mobile devices and numerous di®erent services that are becoming increasingly resourcedemanding, have attracted the attention of many researchers into the area of radio resource planning and optimization. Due to network complexity, these tasks require intelligent, automated approaches that are able to deal with many factors in order to enable design of high capacity networks with a high service quality at the lowest possible cost. This is a perfect application of optimization theory.

    In this thesis, mathematical optimization is considered as the main approach to designing and improving the performance of wireless networks such as Universal Mobile Telecommunications System (UMTS), Wireless Local Area Networks (WLANs) and ad hoc networks. Due to different underlying access technologies, the optimization goals, design parameters and system limitations vary by network type. Therefore, the goals of the presented work are to identify a relevant optimization problem for each type of network, to model the problem and to apply the optimization approach in order to facilitate wireless network planning and improve radio resource utilization.

    The optimization problems addressed in this thesis, in the context of UMTS networks, focus on minimizing the total amount of pilot power which, from the modeling point of view, is not just an amount of power consumed by a certain type of control signal, but also an indicator of the interference level in the network and means of controlling cell coverage. The presented models and algorithms enable °exible coverage planning and optimization of pilot power and radio base station antenna confiration in large networks.

    For WLANs, in the First part of the study, the access point placement and the channel assignment problems are considered jointly to maximize net user throughput and minimize co- and adjacent channel interference and contention. The second part of the study addresses the contention issue and involves, among the other decisions, optimization of access point transmit power.

    Due to the dynamic and infrastructureless nature of ad hoc networks, static resource planning is less suitable for this type of network. Two algorithmic frameworks which enable dynamic topology control for power-efficient broadcasting in stationary and mobile networks are presented. In both frameworks, the performance of the presented algorithms is studied by simulations.

  • 5.
    Siomina, Iana
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Wireless LANs Planning and Optimization2005Rapport (Annet vitenskapelig)
    Abstract [en]

    The report addresses the problem of optimizing the access points placement and channel assignment for IEEE 802.11 Wireless LANs and gives a detailed description of the work that has been carried out during the author's research vizit at Zuse Institute of Berlin within the STSM Programme of the COST (European Cooperation in the Field of Scientific and Technical Research) Action TIST (inside of the Telecomunications, Information Science and Tecnology domain) 293.   

  • 6.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Ahlinder, S.
    Volvo Technology Corporation, SE-412 88 Göteborg, Sweden.
    Lean optimization using supersaturated experimental design2008Inngår i: Applied Numerical Mathematics, ISSN 0168-9274, E-ISSN 1873-5460, Vol. 58, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In practice, product development implies studying numerous factors that affect the final product quality and define its cost. The selection of factors to study has been left to engineers. This work is an attempt for an opposite approach which does not require selecting a small subset of factors explicitly but allows us to briefly investigate most of the parameters using a limited number of experiments. Even more, we assume that the number of experiments can be smaller than the number of parameters. The paper focuses on statistical optimization using supersaturated experimental design. The authors present a new algorithm for exploring a multi-parameter system and performing a lean optimization procedure without spending a lot of efforts. The algorithm aims at making the industrial experimental process more efficient both from the resource consumption and the economic point of view. This is especially important in first stages of system analysis and has therefore practical application in industry where each experiment is very expensive and time-consuming. Numerical results demonstrate efficiency of the algorithm which has been tested for both theoretical and realistic models. © 2006 IMACS.

  • 7.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Geerdes, Hans-Florian
    Optimization Zuse Institute of Berlin.
    Planning Wireless LANs in Indoor Office Environments2006Inngår i: ADONET/COST293 Spring School on Combinatorial Optimization and Communication Networks,2006, 2006Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The poster addresses the problem of optimizing the access points placement and channel assignment in Wireless LANs complient with the IEEE 802.11 standard. We present the problem formulation, solution approach, and the obtained results for a scenario based on real planning data for an indoor office environment.

  • 8.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Värbrand, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    An effective optimization algorithm for configuring radio base station antennas in UMTS networks2006Inngår i: The 64th IEEE Vehicular Technology Conference 2006 Fall VTC2006-fall,2006, IEEE , 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose an effective algorithm for configuring radio base station antennas in UMTS networks and optimizing the Primary Common Pilot Channel (CPICH) transmit power. The algorithm is based on tabu search and utilizes the advantage of a problem size reduction technique which allows us to detect the most critical parts of the service area where the coverage loss probability is very sensitive to the choice of antenna configuration in neighboring cells. We report numerical results for a test network originating from a realistic planning scenario for the city of Lisbon.  

  • 9.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Värbrand, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Automated optimization of service coverage and base station antenna configuration in UMTS networks2006Inngår i: IEEE wireless communications, ISSN 1536-1284, E-ISSN 1558-0687, Vol. 13, nr 6, s. 16-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Deployment and maintenance of UMTS networks involve optimizing a number of network configuration parameters in order to meet various service and performance requirements. In this article we address automated optimization of service coverage and radio base station antenna configuration. We consider three key configuration parameters: transmit power of the common pilot channel (CPICH), antenna tilt, and antenna azimuth. CPICH power greatly influences coverage. From a resource management point of view, satisfying the coverage requirement using minimum CPICH power offers several performance advantages. In particular, less CPICH power leads to less interference and higher system capacity. Optimal CPICH power, in its turn, is highly dependent on how the other two parameters, tilt and azimuth, are configured at radio base station antennas. Optimizing antenna tilt and azimuth network-wise, with the objective of minimizing the CPICH power consumption, is a challenging task. The solution approach in this article adopts automated optimization. Our optimization engine is a simulated annealing algorithm. Staring from an initial configuration, the algorithm searches effectively in the solution space of possible configurations in order to find improvements. The algorithm is computationally efficient, thus, we can optimize large networks without using excessive computing resources. We present a case study for a UMTS planning scenario in Lisbon. For this network, automated optimization saves up to 70 percent of the CPICH power used in the reference network configuration. In addition, the optimized network configuration offers significant performance improvement in terms of fewer overloaded cells and lower downlink load factor. © 2006 IEEE.

  • 10.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Värbrand, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Pilot power optimization and coverage control in WCDMA mobile networks2007Inngår i: Omega: The International Journal of Management Science, ISSN 0305-0483, E-ISSN 1873-5274, Vol. 35, nr 6, s. 683-696Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In mobile networks using wideband code division multiple access (WCDMA), common pilot channel (CPICH) signals are used by mobile terminals for channel quality estimation, cell selection, and handover. The strength of the CPICH signal determines the coverage area of the cell, impacts the network capacity, and thereby the quality of service, and is therefore a crucial parameter in network planning and optimization. Pilot power is the most important parameter that allows us to control the strength of the CPICH signal. The more power is spent for pilot signals, the better coverage is obtained. On the other hand, a higher value of the pilot power level in a cell means higher pilot pollution in the network and less power available to serve user traffic in the cell. In this paper, we consider the problem of minimizing the total amount of pilot power subject to a coverage constraint. Our modeling and solution approaches are based on mathematical programming techniques. We present a basic model for pilot power optimization subject to a full coverage constraint as well as its extended version which allows us to study various coverage levels and to consider user traffic distribution over the network. We also propose an efficient algorithm that gives near-optimal solutions to the problem within a reasonable amount of time. We report our numerical experiments for three WCDMA networks of various sizes based on realistic planning scenarios and examine the effect of different levels of the required coverage degree on the total amount of pilot power. © 2006 Elsevier Ltd. All rights reserved.

  • 11.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Värbrand, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Two mathematical programming approaches for pilot power optimization in WCDMA networks2004Inngår i: 8th World Multi-Conference on Systematics, Cybernetics and Informatics,2004, Orlando, FL, USA: The International Institute of Informatics and Systematics , 2004, s. 412-Konferansepaper (Fagfellevurdert)
  • 12.
    Siomina, Iana
    et al.
    Ericsson Research, Ercisson AB, Sweden.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan. Ericsson Research, Ercisson AB, Sweden.
    Analysis of Cell Load Coupling for LTE Network Planning and Optimization2012Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 11, nr 6, s. 2287-2297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    System-centric modeling and analysis are of key significance in planning and optimizing cellular networks. In this paper, we provide a mathematical analysis of performance modeling for LTE networks. The system model characterizes the coupling relation between the cell load factors, taking into account non-uniform traffic demand and interference between the cells with arbitrary network topology. Solving the model enables a network-wide performance evaluation in resource consumption. We develop and prove both sufficient and necessary conditions for the feasibility of the load-coupling system, and provide results related to computational aspects for numerically approaching the solution. The theoretical findings are accompanied with experimental results to instructively illustrate the application in optimizing LTE network configuration.

  • 13.
    Siomina, Iana
    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 Allocation for Enhancing HSDPA Performance at Cell Edges2007Inngår i: Proceedings of the 4th international conference on mobile technology, applications, and systems and the 1st international symposium on Computer human interaction in mobile technology, New York, NY, USA: Association for Computing Machinery (ACM), 2007, s. 112-118Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Power allocated to common pilot channel (CPICH) is an important parameter in performance tuning of UMTS networks. CPICH is used to announce network presence, and hence CPICH power has great influence on the cell coverage pattern. We study automated planning of CPICH power allocation in UMTS networks implementing high speed downlink packet access (HSDPA). A commonly used strategy is to allocate uniformly a constant proportion of the total power available to CPICH. This strategy is not optimized for HSDPA service. Adopting non-uniform CPICH power and minimizing the amount required for coverage lead to spare power that can be re-allocated to HSDPA to improve user throughput. We present a novel approach for optimizing non-uniform CPICH power with emphasis on HSDPA performance at cell edge, where user throughput is typically very low. Our approach is based on a linear-integer mathematical model that ensures CPICH coverage, and optimally utilizes the power saving of CPICH to enhance HS-DPA performance at cell edges. A case study shows that the proposed approach significantly outperforms the uniform CPICH assignment.

  • 14.
    Siomina, Iana
    et al.
    Ericsson Research, Ericsson AB, Stockholm, Sweden.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Enhancing HSDPA Performance via Automated and Large-scale Optimization of Radio Base Station Antenna Configuration2008Inngår i: IEEE Vehicular Technology Conference, 2008. VTC Spring 2008., Piscataway, NJ, USA: IEEE , 2008, s. 2061-2065Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The rapid deployment of High Speed Downlink Packet Access (HSDPA) calls for automated optimization in network planning. In this paper, we study HSDPA performance improvement by means of optimizing base station antenna configuration. We consider networks with mixed HSDPA and Release 99 (R99) services that share the power resource of the cells. We present an optimization framework to capture the relationship between antenna configuration, service coverage, power sharing between R99 and HSDPA, and HSDPA performance, taking into account the influence of cell size and user distribution on HSDPA user throughput. The cost function is targeted at improving the average HSDPA user throughput. The engine of our computational machinery is a simulated annealing algorithm that is able to search and improve antenna configurations effectively and time-efficiently. We report the benefit of our approach for a realistic planning scenario for the city of Lisbon. The experiment demonstrates that automated optimization leads to significantly better HSDPA throughput.

  • 15.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Extending broadcast lifetime in ad hoc networks by distributed and smooth backbone update2006Inngår i: The Third IEEE International Conference on Mobile Ad-hoc and Sensor Systems IEEE MASS¿06,2006, Vancouver, Canada: IEEE , 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present an algorithm for maximizing the lifetime of broadcasting over a virtual backbone in wireless ad hoc networks. The algorithm is fully distributed in performing backbone update, and its message overhead is insensitive to the update interval. Moreover, our algorithm design guarantees backbone connectivity throughout the update process. We present simulation studies to demonstrate that the algorithm can significantly prolong lifetime.

  • 16.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Load balancing in WCDMA networks by adapting pilot power to traffic intensity2004Inngår i: International Conference on Computing, Communications and Control Technologies,2004, The International Institute of Informatics and Systematics: Orlando, FL, USA , 2004, s. 321-Konferansepaper (Fagfellevurdert)
  • 17.
    Siomina, Iana
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan. Ericsson Research, Ericsson AB, Stockholm, Sweden.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Managing a Broadcast Infrastructure in Ad Hoc Networks in Presence of Mobility: A New Algorithmic Framework2007Inngår i: IEEE 65th Vehicular Technology Conference, 2007. VTC2007-Spring., Piscataway, NJ, USA: IEEE , 2007, s. 71-75Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A virtual backbone forms a source-independent broadcast infrastructure in wireless ad hoc networks. Backbone formation amounts to constructing a connected dominating set (CDS) in the underlying graph. CDS construction in static networks is a well-addressed topic, whereas distributed backbone management in mobile networks has been studied to less extent. We present an algorithmic framework for managing a dynamic backbone in presence of node mobility. The framework is designed to be effective in dealing with mobility as well as in keeping backbone size small. Our approach is fully decentralized. Nodes are not required to acquire network topology information other than its local environment. All operations involved in backbone management are distributed. Moreover, the operations do not require coordination in time. As a result, decisions of joining and leaving the backbone are made locally, individually, and asynchronously at nodes. Our simulation study demonstrates the effectiveness of the framework. Even under high mobility, backbone update is satisfactorily fast to maintain backbone connectivity as well as to keep backbone size moderate

  • 18.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Managing a dynamic broadcast infrastructure in mobile ad hoc networks through distributed and asynchronous update of a virtual backbone2006Inngår i: The 25th IEEE Military Communications Conference MILCOM 2006,2006, Washington, DC: IEEE , 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Broadcast communication in wireless ad hoc networks can be implemented by means of a virtual backbone. Backbone nodes forward broadcast messages for others. A classical way of constructing such a backbone is to find a connected dominating set in the underlying graph. Based on this concept, a great amount of research has been devoted to backbone formation in static networks. In contrast, distributed backbone management in the presence of node mobility has been explored to a less extent. We present a distributed algorithm for managing a dynamic broadcast infrastructure in mobile ad hoc networks. The algorithm relies on neither location information nor any kind of global knowledge of the network. What's more, the algorithm does not require time synchronization between nodes. Decisions of joining and leaving the backbone are made locally at nodes. A node joins the backbone if connectivity between some neighbors is seemingly broken. To keep the size of the backbone small, a backbone node applies randomized pruning if its neighbors are connected through other backbone nodes. In our simulation experiments we examine backbone size and connectivity with respect to node mobility. The results demonstrate the effectiveness of the algorithm. 

  • 19.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Maximizing lifetime of broadcasting in ad hoc networks by distributed transmission power adjustment2006Inngår i: The 8th International Conference on Transparent Optical Networks ICTON¿06,2006, 2006Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Broadcasting in wireless ad hoc networks can be implemented through a source-independent virtual backbone. The strategy used for constructing and maintaining the backbone has great influence on lifetime of broadcasting. We present a distributed algorithm for maximizing lifetime. The algorithm performs backbone update by adjusting transmission power of devices to their residual energy levels. A backbone device with a low energy level either reduces its transmission power, or prunes itself from the backbone, provided that the backbone infrastructure can be maintained by increasing the transmission power of other devices having larger amount of residual energy. Our algorithm is characterized by its small message and computational overhead. We present a simulation study to demonstrate the efficiency of the algorithm. Our simulation results show that the algorithm is able to prolong significantly network lifetime.

  • 20.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Minimum pilot power for service coverage in WCDMA networks2008Inngår i: Wireless networks, ISSN 1022-0038, E-ISSN 1572-8196, Vol. 14, nr 3, s. 393-402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pilot power management is an important issue for efficient resource utilization in WCDMA networks. In this paper, we consider the problem of minimizing pilot power subject to a coverage constraint. The constraint can be used to model various levels of coverage requirement, among which full coverage is a special case. The pilot power minimization problem is NP-hard, as it generalizes the set covering problem. Our solution approach for this problem consists of mathematical programming models and methods. We present a linear-integer mathematical formulation for the problem. To solve the problem for large-scale networks, we propose a column generation method embedded into an iterative rounding procedure. We apply the proposed method to a range of test networks originated from realistic network planning scenarios, and compare the results to those obtained by two ad hoc approaches. The numerical experiments show that our algorithm is able to find near-optimal solutions with a reasonable amount of computing effort for large networks. Moreover, optimized pilot power considerably outperforms the ad hoc approaches, demonstrating that efficient pilot power management is an important component of radio resource optimization. As another part of our numerical study, we examine the trade-off between service coverage and pilot power consumption. © 2007 Springer Science + Business Media, LLC.

  • 21.
    Siomina, Iana
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan. Ericsson Research, Ericsson AB, Stockholm, Sweden.
    Yuan, Di
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Optimization of Channel Assignment and Access Point Transmit Power for Minimizing Contention in Wireless LANs2007Inngår i: 5th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks and Workshops, 2007. WiOpt 2007., Limassol, Cyprus: IEEE , 2007, s. 1-10Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We study the problem of optimizing AP configuration in wireless LANs. In particular, we address the issue of simultaneous planning and optimization of access point (AP) transmit power and channel assignment in the network. We aim at improving network performance in terms of reduced contention in the network by controlling the coverage range of APs and minimizing adjacent channel interference. One of the advantages of our model is that it is not limited to a case when only non-overlapping channels are considered but allows us to deal with any channel set that may also include overlapping adjacent channels. By our model, a higher priority is given to solutions in which neighboring APs with large overlapping coverage areas have larger channel distance. Numerical solutions are compared to a reference network configuration with fixed uniform AP power levels and a channel assignment minimizing coverage overlap of APs operating on the same channel. Our numerical experiments demonstrate that AP transmit power control jointly optimized with the channel assignment can significantly improve network performance in terms os contention and interference distribution.

  • 22.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Optimization of pilot power for load balancing in WCDMA networks2004Inngår i: GLOBECOM,2004, New York, NY, USA: IEEE , 2004Konferansepaper (Fagfellevurdert)
  • 23.
    Siomina, Iana
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Yuan, Di
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Optimization of pilot power for service coverage and smooth handover2004Inngår i: Mobile and Wireless Communications Networks,2004, New York, NY, USA: Springer Verlag , 2004, s. 191-Konferansepaper (Fagfellevurdert)
  • 24.
    Siomina, Iana
    et al.
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    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
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    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
    Soft handover overhead control in pilot power management in WCDMA networks2005Inngår i: IEEE 61st Vehicular Technology Conference VTC2005-Spring,2005, Piscataway, New Jersey, USA: IEEE , 2005Konferansepaper (Fagfellevurdert)
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    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem.
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    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Pilot power optimization in WCDMA networks2004Inngår i: 2nd Workshop on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks,2004, Cambridge, UK: Cambridge University Press , 2004, s. 191-Konferansepaper (Fagfellevurdert)
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