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  • 1.
    Ahlin, Lars
    et al.
    Swedish Defence Research Agency (FOI).
    Englund, Eva
    FOI.
    Jönsson, Christian
    FOI.
    Söderquist, Ingrid
    FOI.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Maguire Jr., Gerald Q.
    KTH, Superseded Departments, Teleinformatics.
    Automous Tactical Communications Possibilities and Problems1997In: MILCOM 97 Proceedings, 1997, 393-397 p.Conference paper (Refereed)
    Abstract [en]

    In the battlefield of the future, more and more information will be available for making decisions on a tactical level, provided that this information can be dispersed rapidly and accurately. As a consequence, advanced tactical decision support that now is limited to advanced platforms (e.g. combat aircrafts) will become available at a much lower level, ranging from different kinds of vehicles, down to the individual soldier by means of ultra-light weight ``wearable'' equipment.

    Establishing reliable wireless communications in such a large group of users with unprecidented bandwidth demands and requirements on survivability constitutes a considerable enginerring challenge. In the paper we will, after a short review of some existing approaches, investigate the specific engineering challenges and the fundamental limitations of such low level, autonomous communication systems. Further we give an example of a system architecture, harmonized with a proposed structure for third generation commercial wireless systems (e.g. UMTS). Our conclusions show that mainly distributed computing complexity, device power consumption and available bandwidth constitute the fundamental problems.

  • 2.
    Ahlin, Lars
    et al.
    Swedish Defence Research Agency (FOI).
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Automous tactical communication: problems & possibilities1996Conference paper (Refereed)
    Abstract [en]

    On the battlefield of the future, more and more information will be available for making decisions on a tactical level, provided that this information can be dispersed rapidly and accurately. Sophisticated electronic equipment for communication, information processing and for collection of sensor data are becoming light-weight, small and inexpensive. As a consequence, advanced tactical decision support that now is limited to advanced platforms (e.g. combat aircrafts) will become available at a much lower level, maybe down to the individual soldier. In such a scenario, the number of communicating entities is one or several orders of magnitude larger than in todays tactical systems. Establishing reliable wireless communications in such a large group constitutes a considerable engineering challenge. In this paper we investigate the specific engineering challenges and the fundamental limitations of such low level, autonomous communication systems. Our conclusions are that mainly distributed computing complexity, device power consumption and available bandwidth constitute the fundamental problems.

  • 3.
    Ahlin, Lars
    et al.
    FOI.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT).
    Ben Slimane, Slimane
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Principles of Wireless Communications2006Book (Refereed)
    Abstract [en]

    This textbook provides the reader with a basic understanding of the design and analysis of wireless and mobile communication systems. It deals with the most important techniques, models and tools used today in the design of mobile wireless links and gives an introduction to the design of wireless networks. Topics covered include: fundamentals of radio propagation and antennas; transmission schemes, including modulation, coding and equalising schemes for broadband wireless communications; diversity systems; wireless data transmission; introduction to Wireless Network design and resource management. The fundamentals are illustrated by examples from state-of-the-art technologies such as OFDM, WCDMA, WLANs and others. The book contains a significant number of worked examples and more than 160 problems with answers. It is intended for use in a first graduate course in wireless communications and the reader should be familiar with the fundamentals of probability and communication theory.

  • 4.
    Anderlind, Erik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    A Traffic Model for Non-Real-Time Data Users in Wireless Radio Networks1997In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 1, no 2, 37-39 p.Article in journal (Refereed)
    Abstract [en]

    Based on an analysis of Internet protocols for data communication, we propose a simple model for future data traffic in wireless radio networks. Model parameters are selected so as to resemble traffic from the Worldwide Web (WWW) access and from distributed file systems. By changing a single parameter, the model can be switched between resembling up- or down-link traffic. The model is intended for design and performance analysis of radio resource allocation algorithms in future wireless systems.

  • 5.
    Andersin, Michael
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Rosberg, Zvi
    IBM, Haifa Research Laboratory.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Distributed Discrete Power Control in Cellular PCS1998In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 6, no 3, 211-213 p.Article in journal (Refereed)
    Abstract [en]

    Transmitter power control has proven to be an efficient method to control cochannel interference in cellular PCS, and to increase bandwidth utilization. Power control can also improve channel quality, lower the power consumption, and facilitate network management functions such as mobile removals, hand-off and admission control. Most of the previous studies have assumed that the transmitter power level is controlled in a continuous domain, whereas in digitally power controlled systems, power levels are discrete. In this paper we study the transmitter power control problem using only a finite set of discrete power levels. The optimal discrete power vector is characterized, and a Distributed Discrete Power Control (DDPC) algorithm which converges to it, is presented. The impact of the power level grid on the outage probability is also investigated. A microcellular case study is used to evaluate the outage probabilities of the algorithms.<

  • 6.
    Andersin, Michael
    et al.
    KTH, Superseded Departments, Teleinformatics.
    Rosberg, Zvi
    IBM, Haifa Research Laboratory.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Gradual removals in cellular PCS with constrained power control and noise1995In: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 1995, 56-60 p.Conference paper (Refereed)
    Abstract [en]

    In this paper we study the mobile removal problem in a cellular PCS network where transmitter powers are constrained and controlled by a distributed constrained power control (DCPC) algorithm. Due to transmitter mobility and random signal propagation, there are system states where not all transmitters can be supported, even under the optimal power control. Thus, some of them should be removed. It can be shown that finding the optimal removal set is an NP-complete problem, and therefore gives rise to heuristic algorithms. In this paper we study and compare among three classes of transmitter removal algorithms, one-by-one removals, multiple removals and power control with removals combined. All removal algorithms are compared with respect to their outage probabilities and their time to convergence to a steady state. The power control with removals combined algorithm emerges as the best approach with respect to both criteria.

  • 7.
    Andersin, Michael
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Rosberg, Zvi
    IBM, Haifa Research Laboratory.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Gradual Removals in Cellular PCS with Constrained Power Control and Noise1996In: Wireless networks, ISSN 1022-0038, E-ISSN 1572-8196, Vol. 2, no 1, 27-43 p.Article in journal (Refereed)
    Abstract [en]

    In this paper we study the mobile removal problem in a cellular PCS network where  transmitter powers are constrained and controlled by a Distributed Constrained  Power Control (DCPC) algorithm. Receivers are subject to non­negligible noise,  and the DCPC attempts to bring each receiver's CIR above a given target. To  evaluate feasibility and computational complexity, we assume a paradigm where  radio bandwidth is scarce and inter­base station connection is fast.  We show that finding the optimal removal set is an NP-Complete problem,  giving rise for heuristic algorithms. We study and compare among three classes  of transmitter removal algorithms. Two classes consist of algorithms which are  invoked only when reaching a stable power vector under DCPC. The third class  consist of algorithms which combine transmitter removals with power control.  These are One-by-one Removals, Multiple Removals, and Power Control with Removals Combined. In the class of power control with removals combined, we also  consider a distributed algorithm which uses the same local information as DCPC  does.

    All removal algorithms are compared with respect to their outage probabilities  and their time to converge to a stable state. Comparisons are made in a hexagonal macro-cellular system, and in two metropolitan micro-cellular systems. The  Power Control with Removals Combined algorithm emerges as practically the best  approach with respect to both criteria.

  • 8.
    Andersin, Michael
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Rosberg, Zvi
    IBM, Haifa Research Laboratory.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Soft Admission in Cellular PCS with Constrained Power Control and Noise1995In: Proc 5th WINLAB Workshop on Third Generation Wireless Information Networks, 1995, 287-320 p.Conference paper (Refereed)
    Abstract [en]

    We study the mobile admission control problem in a cellular PCS network where trans- mitter powers are constrained and controlled by a Distributed Constrained Power Control (DCPC) algorithm. Receivers are subject to non-negligible noise, and the DCPC attempts to bring each receiver's CIR (Carrier to Interference Ratio) above a given quality target. Two classes of distributed admission controls are considered. One is a Non-Interactive Admission Control (N-IAC), where an admission decision is instantaneously made based on the system state. The other is an Interactive Admission Control (IAC), under which the new mobile is permitted to interact with one or more potential channels before a decision is made. The algorithms are evaluated with respect to their execution time, and their decision errors. Two types of errors are examined. Type I error, where a new mobile is erroneously accepted and results an outage; and type II error, where a new mobile is erroneously rejected and results in blocking. The algorithms in the N-IAC class accept a new mobile, if and only if the uplink and the downlink interferences are below certain corresponding thresholds. These algorithms are subject to errors of type I and type II. In the IAC class, we derive a Soft and Safe (SAS) admission algorithm, which is type I and type II error free, and protects the CIRs of all active links at any moment of time. A Fast-SAS version which is only type I error free, is proposed for practical implementation, and evaluated in several case studies.

  • 9.
    Andersin, Michael
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Roseberg, Zvi
    Soft and safe admission control in cellular networks1997In: IEEE/ACM Transactions on Networking, ISSN 1063-6692, E-ISSN 1558-2566, Vol. 5, no 2, 255-265 p.Article in journal (Refereed)
    Abstract [en]

    We study the mobile admission control problem in a cellular PCS network where transmitter powers are constrained and controlled by a distributed constrained power control (DCPC) algorithm. Receivers are subject to nonnegligible noise, and the DCPC attempts to bring each receiver's CIR (carrier-to-interference ratio) above a given quality target. Two classes of distributed admission control are considered. One is a noninteractive admission control (N-IAC), where an admission decision is instantaneously made based on the system state. The other is an interactive admission control (IAC), under which the new mobile is permitted to interact with one or more potential channels before a decision is made. The algorithms are evaluated with respect to their execution time and their decision errors. Two types of errors are examined: type I error, where a new mobile is erroneously accepted and results in outage; and type II error, where a new mobile is erroneously rejected and results in blocking. The algorithms in the N-IAC class accept a new mobile if and only if the uplink and the downlink interferences are below certain corresponding thresholds. These algorithms are subject to errors of type I and type II. In the IAC class, we derive a soft and safe (SAS) admission algorithm, which is type I and type II error free, and protects the CIR's of all active links at any moment of time. A fast-SAS version, which is only type I error-free, is proposed for practical implementation, and is evaluated in several case studies.

  • 10.
    Badia, Leonardo
    et al.
    University of Ferrara.
    Lindström, Magnus
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zorzi, Michele
    University of Ferrara.
    An Economic Model For The Radio Resource Management In Multimedia Wireless Systems2004In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 27, no 11, 1056-1064 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we study the connection between radio resource management (RRM) and economic parameters, whose application in multimedia communication system is a challenging task. In fact, a real network provider has to consider other parameters, besides the common goals of RRM like throughput maximisation or meeting constraints connected with the quality of service. In particular, when the financial needs of the provider and the reaction of the users to prices are taken into account, economics have to be introduced in the analysis. We intend to study multimedia communication systems by including well-known economic models and reasonable considerations in the usual radio resource allocation scenario. To do this, we present a model of users' satisfaction, which considers the effects of both users' request and price paid. In this way, it is possible to investigate the relationship between the radio resource allocation and the provider revenue. Other conclusions can be derived as well, e.g. for the pricing strategy planning or the network dimensioning. Thus, we give analytical insight and numerical results, which highlight that the network management is heavily affected by the economic scenario.

  • 11.
    Badia, Leonardo
    et al.
    Department of Engineering, University of Ferrara, 44 100 Ferrara, Italy.
    Lindström, Magnus
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zorzi, Michele
    Dipartimento di Ingegneria - Universit`a di Ferrara, Ferrara, Italy.
    An Economic Model for the Radio Resource Management in Multimedia Wireless Systems2003Conference paper (Refereed)
    Abstract [en]

    In this paper, we study the connection between Radio Resource Management and economic parameters, whose application in multimedia communication system is a challenging task. In fact, a real network provider has to consider other parameters, besides the common goals of Radio Resource Management like throughput maximisation or meeting constraints connected with the Quality of Service. In particular, when the financial needs of the provider and the reaction of the users to prices are taken into account, economics have to be introduced in the analysis. We intend to study multimedia communication systems by including well-known economic models and reasonable considerations in the usual Radio Resource Allocation scenario. To do this, we present a model of users'satisfaction, which considers the effects of both users' request and price paid. In this way it is possible to investigate the relationship between the Radio Resource Allocation and the provider revenue. Other conclusions can be derived as well, e.g., for the pricing strategy planning or the network dimensioning. Thus, we give analytical insight and numerical results which highlight that the network management is heavily affected by the economic scenario.

  • 12.
    Badia, Leonardo
    et al.
    University of Ferrara, Italy.
    Lindström, Magnus
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zorzi, Michele
    University of Ferrara, Italy.
    Demand and Pricing Effects on the Radio Resource Allocation of Multimedia Communication Systems2003In: Conference Record / IEEE Global Telecommunications Conference, IEEE , 2003, Vol. 7, 4116-4121 p.Conference paper (Refereed)
    Abstract [en]

    Over the years, Radio Resource Management has been benchmarked mostly by its technical merits. For a service provider, however, also economics must be reckoned with. When the financial needs of the provider and the satisfaction of the users are considered, common objectives in radio resource management like maximising throughput or meeting various quality constraints, may no longer be sufficient. We analyse next generation communication systems by including models of economics, presented in the literature, and reasonable considerations to depict the users/provider relationship in a generalised multimedia environment. In particular, we develop a model of users' satisfaction, in which both requested Quality of Service and price paid are taken into account. The model enables us to investigate how resource allocation dynamics affect operator revenues and to derive some useful insights. The Radio Resource Management can be shown to highly depend on economic considerations. The provider's task to determine the best usage of the network capacity is heavily affected by the users' service demand and their reactions to the pricing policy. Thus, the economic scenario needs to be taken into account to efficiently exploit the constrained radio resource.

  • 13.
    Berg, Miguel
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Pettersson, Stefan
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    A Radio Resource Management Concept for "Bunched" Personal Communication Systems1997Conference paper (Refereed)
    Abstract [en]

    The  radio  resource  management  (RRM)  techniques  used  in  current  2nd  generation  mobile communication systems rely heavily on fixed frequency or timeslot allocation  techniques  which  are  not  well  suited  for  large  variations  in  data  rates.  Spread  spectrum  systems  proposed  provide  partial  solutions  to  this  problem  but  exhibit  deficiencies  when  faced  with  uneven  user  populations.  The  overall  objective  of  ACTS  project  AC090  FRAMES  is  to  define,  develop  and  evaluate  a  wideband  multiple radio access scheme fulfilling  the UMTS requirements. Within  the project  several RRM concepts have been proposed. The "bunch" concept discussed  in  this  paper uses synchronous dynamic physical layer radio resource reservation combined  with fast SIR based power control in a local cluster ("bunch").  Uncontrolled, "inter­  bunch",  interference  is  handled  by  time/frequency  hopping  ("interference  averaging"). In the paper some initial performance results are presented.

  • 14. Berggren, F.
    et al.
    Kim, S. L.
    Jantti, R.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Joint power control and intracell scheduling of DS-CDMA nonreal time data2001In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 19, no 10, 1860-1870 p.Article in journal (Refereed)
    Abstract [en]

    The performance of DS-CDMA systems depends on the success in managing interference arising from both intercell and intracell transmissions. Interference management in terms of power control for real time data services like voice has been widely studied and shown to be a crucial component for the functionality of such systems. In this work we consider the problem of supporting downlink nonreal time data services, where in addition to power control, there is also the possibility of controlling the interference by means of transmission scheduling. One such decentralized schedule is to use time division so that users transmit in a one-by-one fashion within each cell. We show that this has merits in terms of saving energy and increasing system capacity. We combine this form of intracell scheduling with a suggested distributed power control algorithm for the intercell interference management. We address its rate of convergence and show that the algorithm converges to a power allocation that supports the nonreal time data users, using the minimum required power while meeting requirements on average data rate. Numerical results indicate a big potential of increased capacity and that a significant amount of energy can be saved with the proposed transmission scheme.

  • 15. Berggren, F.
    et al.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Throughput and energy consumption tradeoffs in pathgain-based constrained power control in ALOHA networks2000In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 4, no 9, 283-285 p.Article in journal (Refereed)
    Abstract [en]

    Power control has been proposed as a tool to improve the performance of packet radio systems in terms of increased throughput and battery lifetime for mobile terminals. In this paper we study the tradeoff between transmitter dynamic range, average energy consumption and the achievable throughput for a simple pathgain based power control algorithm in a slotted ALOHA radio system. The results show that increasing the throughput significantly by means of transmitter power control requires only a very moderate increase in energy consumption and transmitter dynamic range.

  • 16.
    Berggren, Fredrik
    et al.
    KTH, Superseded Departments, Wireless at KTH.
    Queseth, Olav
    KTH, Superseded Departments, Wireless at KTH.
    Zander, Jens
    KTH, Superseded Departments, Wireless at KTH.
    Asp, Börje
    Swedish Defence Research Agency (FOI).
    Jönsson, Christian
    Swedish Defence Research Agency (FOI).
    Stenumgaard, Peter
    Swedish Defence Research Agency (FOI).
    Kviselius, Niklas Z
    CIC, Stockholm School of Economics.
    Thörngren, Bertil
    CIC, Stockholm School of Economics.
    Dynamic Spectrum Access, Phase 1 Scenarios and research challenges2004Report (Other academic)
    Abstract [en]

    The currently used mechanisms for spectrum management are a contributing factor to the long lead times from innovation to market in wireless technologies andsystems. This has in turn been a major contributing factor to the dominance of the large telecom companies in the European and World markets, whereas very few innovative enterprises have exhibited consistent growth, although the technicalcompetence in Sweden is very high in this area. Alternative spectrum management regimes, such as the introduction of "unlicensed bands" have proven very effective in lowering entry thresholds for smaller companies (e.g the WLAN business). In addition, experts claim that the spectrum requirements for communication purposes will increase by as much as 200-300 % up to 2010. At the same time the actual usage of the electromagnetic spectrum is very inefficient.

    The project aims at studying new more, flexible, spectrum allocation regimeswhich, in combination with new technologies, such as multi-radio access, novelbroadband access techniques, software defined radio and spatial techniques (e.g.smart antennas, multi-hop schemes) have the potential of lowering the entry thresholds for new actors and provide radical improvement to the efficiency ofspectrum usage. Further the aim is to investigate the economic and regulatory consequences of such Dynamic Spectrum Access technologies and managementregimes. The results will provide input to future policies in spectrum management. The project has been divided into a first, pre-study phase and a second, research phase. The first phase was launched in Dec of 2004 and the second phase is planned to start in Jan 2005. The first phase of the project, reported here, has the aim toprovide a qualitative assessment of the potential benefits of dynamic spectrum access regimes. The analysis in the report and other studies in the area, indeed indicate there is a potential to both lower the entry thresholds for new actors as well as provide radical improvement to the efficiency of spectrum usage. The area isdefinitely of significant issues and the project should be continued studying the DSA concepts in more detail.

    Further, using a systematic procedure, a number of critical areas and bottleneck problems were identified. Our conclusion is that more research is needed in theseareas to achieve the above mentioned benefits. As `side effect' in this procedure, a number of novel and interesting spectrum management concepts were derived, e.g.the `real-time spectrum trading' and `use rights' concepts. Out of this gross list ofinterest problems, a number of highly important problems were selected, matching the competence of the project team. These problems are proposed to be the focus ofthe next phase in the project.

    Finally, the report provides an overview of the most important ongoing research and policy-making activities in the DSA-area.

  • 17.
    Bria, Aurelian
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Flament, Maxime
    Chalmers University of Technology.
    Gessler, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wu, Jiang
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zander, Jens
    KTH, Superseded Departments, Wireless at KTH.
    Overall design of 4th Generation Wireless Infrastructures (4GW)2002Conference paper (Refereed)
    Abstract [en]

    An important factor contributing to this uncertainty is that we have very limited knowledge about the future environment in which a fourth generation wireless infrastructure should function. Which of today's systems will still exist when a potential 4G infrastructure is deployed? Which systems and solutions will be considered successful then? What technical bottlenecks will be apparent ten years from now? What market impact will third generation wireless systems have? How will this affect user behavior, and user demands? How much money do prospective users have available to pay for services provided over this infrastructure? This paper presents some of the conclusion of of the Fourth Generation Wireless Infrastructure project (4GW) of the Personal Computing and Communications program (PCC), the major Swedish academic research effort on future communications systems launched in late 1997(1). The vision of the PCC project has been "Personal Multimedia to everyone at today's prices for fixed telephony". In 4GW a scenario-based approach has been used to tackle the issue of identifying reasonable research topics. In the paper we will present this method, and demonstrate how it interfaces with traditional research methods in the fields that the 4GW project incorporates. We will also give an overview of some research results from the project. Finally, we will conclude these results as a vision of what fourth generation wireless infrastructures might become

  • 18.
    Bria, Aurelian
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Gessler, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wu, Jiang
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Flament, Maxime
    Chalmers University of Technology.
    4th Generation Wireless Infrastructures: Scenarios and Research Challenges2001In: IEEE personal communications, ISSN 1070-9916, E-ISSN 1558-0652, Vol. 8, no 6, 25-31 p.Article in journal (Refereed)
    Abstract [en]

    A "fourth generation" of wireless systems, likely to appear after the successful deployment of the current third-generation systems, is frequently debated these days. This article presents some of the results of the Fourth Generation Wireless project (4GW) of the Personal Computing and Communications program (PCC), the major Swedish academic research effort on future communications systems, launched in late 1997. In the 4GW project, scenarios have been used as tools for formulating relevant research topics related to future wireless systems. By working with scenarios the project group has been able to challenge some of the assumptions commonly made in the field of wireless research. Since the project group is multidisciplinary, the work has also helped the members of the project group to understand the differences between the research traditions to which they belong. The scenarios, as well as the ensuing research into various wireless related topics, point to a vision of fourth-generation systems where "low-hierarchy" user-deployed infrastructures are the prime candidate. Fourth-generation systems will offer short- to moderate-range communications with very high data rates (>100 Mb/s). They are likely to employ array signal processing and ad hoc operation to provide the required coverage. A key aspect of their design will be the fact that they will be deployed in environments where large-scale wireless, and wired, infrastructures are already in operation.

  • 19.
    Costa, J.
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Miao, Guowang
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Context-Aware Framework for Energy Efficient Machine-to-Machine CommunicationsIn: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896Article in journal (Refereed)
    Abstract [en]

    Cellular network based Machine-to-Machine(M2M) communications have been growing rapidly in recentyears, being used in a wide range of services such as security,metering, health, remote control, tracking and so on. A criticalissue that needs to be considered in M2M communications isthe energy efficiency, typically the machines are powered bybatteries of low capacity and it is important to optimize the waythe power is consumed. In search of better M2M systems, wepropose a context-aware framework for M2M communicationsso the machine type communication (MTC) devices dynamicallyadapt their settings depending on a series of characteristicssuch as data reporting mode and quality of service (QoS)features so higher energy efficient is achieved, extending theoperating lifetime of the M2M network. Simulations results willbe provided for four commonly used M2M applications: homesecurity, telehealth, climate and smart metering, showing thatconsiderable energy savings and operating lifetime extension onthe network can be achieved. Thus, contexts play an importantrole on the energy efficiency of a M2M system.

  • 20.
    Englund, Eva
    et al.
    FOI.
    Grönkvist, Jimmi
    Swedish Defence Research Agency (FOI).
    Nilsson, Jan
    FOI.
    Sköld, Mattias
    FOI.
    Sterner, Ulf
    FOI.
    Söderquist, Ingrid
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Tactical Radio Access Networks based on Future Civilian Communication Architectures1999Conference paper (Refereed)
    Abstract [en]

    We investigate architectures where a tactical radio subsystem can integrate in civilian systems. The idea is that civilian communication infrastructure sould be used whereever it is available. One such possibility may be found in the proposed next generation wireless communication system UMTS, where the defition of a Radio Network Subsystem (RNS), encapsulating all the features of wireless mobile communications has been proposed. We adopt this design paradigm to see if it is possible to find a low cost military network (by maximal use of civilian network technology and communication applications). The idea is to within the framework of an RNS, encapsulate also features specific to tactical wireless communications, a Tactical Radio Access Network (TRAN). Based on UMTS we describe two system concepts and architectures for designing a TRAN. Furthermore, feasibility investigation of the concepts is conducted.

  • 21.
    Ergin, Dinc
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Vondra, Michal
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Hofmann, Sandra
    Schupke, Dominic
    Prytz, Mikael
    Bovelli, Sergio
    Frodigh, Magnus
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    In-Flight Broadband Connectivity: Architectures and Business Models for High Capacity Air-to-Ground Communications2017In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896Article in journal (Refereed)
    Abstract [en]

    In-flight broadband connectivity (IFBC) is a significant open market for mobile network operators considering more than 3.3 billion passengers being served by airlines in2015. On-board broadband services are provided via air-to-ground(A2G) connectivity through direct A2G communications(DA2GC) and satellite A2G communications (SA2GC). Available on-board connectivity systems have significant limitations: high latency in SA2GC and low capacity in DA2GC. The customer expectancy is multi-Mbps connections in every seat which leads to capacity requirements of Gbps to the aircraft. Creation of high capacity IFBC requires a collaborative interaction between different industrial partners. For this reason, we investigate A2Garchitectures in terms of economic and technical perspectives, and propose business models by identifying new roles and positioning them in the A2G business ecosystem. In addition, we provide an extensive summary of the state-of-the-art and future improvements for A2G communications.

  • 22.
    Ericson, Thomas
    et al.
    Department of Electrical Engineering, Linköping University.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Meteor Burst Communication without feedback1995In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 43, no 234, 851-857 p.Article in journal (Refereed)
    Abstract [en]

    Traditional meteor burst communication (MBC) systems are duplex (or half-duplex) systems. These systems provide the transmitter with feedback information for the detection of usable meteor trails. To achieve this feedback, a high power transmitter is required also at receive-only sites. In this paper, however, we discuss the application of channel coding to construct a true broadcast-type MBC system that allows for the simultaneous reception of messages at several receiving sites. Furthermore, MBC-systems without feedback allow for simple low power receivers that are impossible to to detect. Suitable codes, system performance and implementation complexity aspects are considered. Simulations with actual field trial data show that these systems are feasible and provide reliable, low-cost transmission of broadcast data.

  • 23.
    Ericson, Thomas
    et al.
    Department of Electrical Engineering, Linköping University.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Meteor Burst Communication without Feedback1992Report (Other academic)
  • 24.
    Flament, Maxime
    et al.
    Chalmers University of Technology.
    Gessler, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Lagergren, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wu, Jiang
    KTH, Superseded Departments, Teleinformatics.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    An Approach to Fourth Generation Wireless Infrastructures - Scenarios and Key Research Issues1999In: Vehicular Technology Conference, 1999 IEEE 49th, IEEE , 1999, 1742-1746 p.Conference paper (Refereed)
    Abstract [en]

    Studying the feasibility and viability of various future infrastructure architectures and potential road-maps of their deployment is the focus of the 4th Generation Wireless Infrastructures (4GW) project within the strategic Personal Computing and Communication (PCC) program (Molin 1998). In attempting to realize the PCC vision “mobile multimedia to all at today's prices for fixed telephony”, a difficult problem arises. In contrast to the process of solving engineering and business problems in current or imminent wireless systems, where system concepts, requirements and markets are reasonably well known, very little is known about these things over a 10 year horizon. The approach used in the project to tackle this problem, is to use various scenario techniques. Plausible scenarios which describe the telecommunication scene in 2010 and which are used to determine potential technological and other bottlenecks in order to find key areas for research in this field are a very important element in these studies. Some of these scenarios are presented in this paper, together with some implications regarding bottlenecks and key research issues. The results are presented in terms of working assumptions (WAs) used with the project. The WAs are also proposed to provide a framework for interrelating different research activities within PCC.

  • 25.
    Flament, Maxime
    et al.
    Chalmers University of Technology.
    Gessler, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Lagergren, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wu, Jiang
    KTH, Superseded Departments, Teleinformatics.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Key Research Issues in 4th Generation Wireless Infrastructures1998Conference paper (Refereed)
    Abstract [en]

    The world of communication is now developing faster than ever. Telecommunication infrastructure deployment in contrast is a slow and costly process demanding along-range strategic perspective in decision making. As aconsequence, R&D efforts are concerned with problems on a time horizon of 10 years or more. Studying the feasibility and viability of various future infrastructure architectures and potential road-maps of their deployment is the focus for the 4th Generation WirelessInfrastructures project within PCC. Determining technological and other bottlenecks to find key areas forr esearch in this area is a very important element in these studies.The methods used for this purpose are various scenario techniques. Plausible scenarios, describing the telecommunication scene in 2010, have been designed based on a number of global trends in technology,economy and politics. The scenario trends have also been verified by using a Delphi survey among leading industrials and scientists in Sweden. Based on these trends, three vivid scenarios are built which implicitly describe the different trends that have been created, for instance, the Big Brother, the Anything Goes, and thePocket Computing. At the end of the paper, the implications of the scenarios to the infrastructure research areas are discussed. In particular, the working assumptions and key research problems in each PCC/4GW work package are revisited and prioritized according to the scenarios. The scenarios are also proposed to provide a framework for inter-relating different research activities within PCC.

  • 26.
    Flament, Maxime
    et al.
    Chalmers University of Technology.
    Gessler, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Lagergren, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wu, Jiang
    KTH, Superseded Departments, Teleinformatics.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Scenarios - A tool for starting a research process1998Conference paper (Refereed)
    Abstract [en]

    Scenarios can be used as a tool for starting a research process within a group. When putting together a research group of people with different backgrounds, differentcompetencies and different preconceived ideas, special attention has to be put on the problem of integration.Many different "tools" can be used to help merging thedifferent approaches of the individuals constituting thegroup. One such tool is scenario work. Trends arecreated by analyzing and structuring the environment around the project. Combining and extrapolating the trends gives a basis for creating the scenarios. The scenarios are then used to help refining research issues. Both the process and the result are hence of importance. The process aims at revealing the different approachesand possible conflicts due to the different  scientific andresearch traditions among the members of the group. Theresult forms a basis for refining and limit the researchquestion.

    The work within the 4th Generation Wireless Infrastructure project group of the PCC-project aims atfinding important design issues for the infrastructure of a future wireless communication system. Using the scenarios as a starting point the research questions originally put, have been successfully challenged andrefined.

  • 27.
    Flament, Maxime
    et al.
    Chalmers University of Technology.
    Gessler, Fredrik
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lagergren, Fredrik
    KTH, Superseded Departments, Industrial Economics and Management.
    Queseth, Olav
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Stridh, Rickard
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Unbehaun, Matthias
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wu, Jiang
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Zander, Jens
    KTH, Superseded Departments, Wireless at KTH.
    Telecom scenarios for the 4th Generation Wireless Infrastructures1998Conference paper (Refereed)
    Abstract [en]

    Telecommunication infrastructure deployment, incontrast to the rest of the communication area, is a slowand costly process, demanding a long-range strategic perspective in decision making. Determining key issues for strategic research in this area is thus very important. This paper describes detailed work to that aim, within the PCC project. The aim was to find possible scenariosfor the 4th Generation Wireless Infrastructures (4GW)around year 2010 and to determine their implications onthe direction of research in wireless communications.

    In this scenario work, a number of trends were created based on the current state of technology, economy and politics. These trends are verified by using Delphi methods. Based on these trends and additional research,three vivid scenarios are built, which picture differentways the trends may develop, The scenarios are called:"Big Brother Scenario", "Anything-Goes Scenario" and"Pocket Computing Scenario". At the end, the paper discusses the implications of the scenarios on thewireless communication research areas. In particular, the working assumptions and key research problems in eachwork package in the 4th Generation Wireless Infrastructure project are verified and prioritized according to the scenarios.

  • 28.
    Frodigh, Magnus
    et al.
    Ericsson Radio Systems.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Joint power control in cellular radio systems1995In: Proceedings of the 1995 6th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC'95: Toronto, Can; 27 September 1995 through 29 September 1995, IEEE , 1995, 41-45 p.Conference paper (Refereed)
    Abstract [en]

    Transmitter power control has proven to be an efficient method to control interference and to improve spectrum utilization in cellular and personal communication systems. Previous results have shown that a significantly higher capacity may be reached, even if the system is subject to (practical) power constraints. Since in most cellular systems a duplex link is required, adequate transmission quality has to provided simultaneously in the down- and up-links. Previous results have shown that the same C/I is achievable in both the up- and down-links when the transmitter powers are not limited. We investigate the properties and the performance of C/I-based power control schemes for the more realistic situation where such power constraints apply. The probability that a solution exists within the power constraints is derived by simulations. Results show that the probability that both the up and down link are supported (duplex link) is not significantly lower than the probability that only an individual link (only the up link or only the down link) is supported.

  • 29.
    Frodigh, Magnus
    et al.
    Ericsson Radio Systems.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    On the Spatital Capacity of Slotted Packet Radio Systems with Capture1991Conference paper (Refereed)
  • 30. Furuskar, A.
    et al.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Multiservice allocation for multiaccess wireless systems2005In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 4, no 1, 174-184 p.Article in journal (Refereed)
    Abstract [en]

    This paper discusses principles for allocating multiple bearer services onto different subsystems in multiaccess wireless systems. Based on the included subsystem's multiservice capacities, under certain constraints near-optimum subsystem service allocations that maximize combined multiservice capacity are derived through simple optimization procedures. These favorable service allocations are either extreme points where services, as far as possible, are allocated to the subsystems best at supporting them, or they are characterized by the relative efficiency of supporting services being equal in all subsystems. The consequences of this include that services should typically be mixed in subsystems with convex capacity regions and isolated in subsystems with concave capacity regions. Simple user assignment algorithms based on this are also discussed. Additionally, illustrating the main findings of the analysis, some system examples are given, including a case study with combined global system for mobile communications (GSM) and wideband code-division multiple-access (WCDMA) systems. The gain of using the proposed service allocation principles compared to a reference case of maintaining equal service mixes in all subsystems depends on the shape of the subsystem capacity regions; the more different the capacity regions, the larger the gain. In the GSM and WCDMA case study, capacity gains of up to 100% in terms of supported data users for a fixed voice traffic load are achieved.

  • 31.
    Giles, Tim
    et al.
    KTH, Superseded Departments, Wireless at KTH.
    Markendahl, Jan
    KTH, Superseded Departments, Wireless at KTH.
    Zander, Jens
    KTH, Superseded Departments, Wireless at KTH.
    Zetterberg, Per
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Karlsson, P
    Cost drivers and deployment scenarios for future broadband wireless networks: Key research problems and directions for research2004In: VTC2004-SPRING: 2004 IEEE 59TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, PROCEEDINGS, NEW YORK: IEEE , 2004, 2042-2046 p.Conference paper (Refereed)
    Abstract [en]

    The most prominent problem in providing anywhere, anytime wideband mobile access is the towering infrastructure cost as it is basically proportional to the bandwidth provided. In this paper, we provide a simple, initial, analysis of the various infrastructure cost factors. This analysis shows that, contrary to what one may expect, the infrastructure cost is not dominated by electronic equipment, but rather by other deployment related costs (towers, wiring,, building, network connections) and maintenance costs. In the paper some novel architectural approaches for future wideband mobile access focusing on these dominant cost factors are described and the related key research issues are discussed.

  • 32.
    Giles, Tim
    et al.
    KTH, Superseded Departments, Wireless at KTH.
    Markendahl, Jan
    KTH, Superseded Departments, Wireless at KTH.
    Zander, Jens
    KTH, Superseded Departments, Wireless at KTH.
    Zetterberg, Per
    KTH, Superseded Departments, Wireless at KTH.
    Karlsson, Peter
    TeliaSonera Sweden.
    Lind, Jonas
    Stockholm School of Economics.
    Malmgren, Göran
    Ericsson Research.
    Nilsson, Jan
    Swedish Defense Research Agency.
    Cost Drivers and Deployment Scenarios for Future Braodband Wireless Networks - Key research problems and directions for research2004Conference paper (Refereed)
    Abstract [en]

    The most prominent problem in providing anywhere, anytime wideband mobile access is the towering infrastructure cost as it is basically proportional to the bandwidth provided. In this paper, we provide a simple, initial, analysis of the various infrastructure cost factors. This analysis shows that, contrary to what one may expect, the infrastructure cost is not dominated by electronic equipment, but rather by other deployment related costs (towers, wiring, building, network connections) and maintenance costs. In the paper some novel architectural approaches for future wideband mobile access focusing on these dominant cost factors are described and the related key research issues are discussed.

  • 33. Gomez-Barquero, David
    et al.
    Cardona, Narcis
    Bria, Aurelian
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Affordable mobile TV services in hybrid cellular and DVB-H systems2007In: IEEE Network, ISSN 0890-8044, E-ISSN 1558-156X, Vol. 21, no 2, 34-40 p.Article in journal (Refereed)
    Abstract [en]

    Mobile TV services are expected to become a key application in future wireless networks. The recently proposed terrestrial digital broadcast technology, DVB-H, especially designed for mobile services, is regarded as a powerful alternative to the 3G cellular networks that already offer these services but on a point-to-point basis. Unfortunately, the cost of supporting real-time streaming and full area coverage seems to be very high compared to fixed TV services. In this article we discuss hybrid IP datacast DVB-H and 3G systems as a possible solution for providing affordable network infrastructure and services. Our approach is DVB-H centric. The 3G cellular system plays the role of providing interactivity, error reporting, and repair for the DVB-H broadcast channel. To enable an easy and efficient interworking of DVB-H and 3G, we employ forward error correction at the application layer with digital fountain coding. The main way to provide, lower cost services is to avoid full DVB-H area coverage from the beginning and to perform an incremental DVB-H network deployment that follows the user demand. In this direction, to hide the discontinuity in coverage from the perception of users, we propose to take advantage of the bursty character of DVB-H transmissions and the mobility of users. This is possible by sending additional parity data, either with the DVB-H or the cellular network, in the time intervals between original service bursts. We evaluate the potential DVB-H infrastructure cost savings determined by transmitting additional parity data in DVB-H when targeting vehicular users. The implications of delivering parity data through the cellular network also are discussed. The numerical investigations show a potential for significant cost savings compared with the traditional approaches.

  • 34.
    González Sánchez, Pamela
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Khamit, Saltanat
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Competitive pricing with demand heterogeneity in open wireless access market2011In: International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, 2011Conference paper (Refereed)
    Abstract [en]

    In order to maximize the network profit competitive service providers shall utilize their resources efficiently and price their services taking into account the demand responsiveness in the market. Pricing strategies play an important role in the network performance since they explicitly influence the user demand. Demand uncertainty would cause providers to face lower profits. In this paper, we analyze the price-demand relationship and based on that, we study a competitive pricing game and address an open wireless access market (with different market shares) where service providers' objective is to maximize their profits. The resources are allocated among the users through a proportionally fair divisible auction mechanism. Simulation results show that a resource allocation model, which attracts users to actively participate in the auction, assures fair access while maintaining service providers' profit by adapting the pricing policy with a change in the user demand. Our analysis reveals that the service providers can establish a competitive price of the resources, while capturing a reasonable portion of market share. Under this setting, service providers could learn and predict which pricing policy is beneficial in a competitive environment.

  • 35.
    González Sánchez, Pamela
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Competitive access-point deployment in mobile broadband systems2011In: Proceedings of the 10th Scandinavian Workshop on Wirless Ad-hoc Networks (ADHOC'11), 2011Conference paper (Refereed)
  • 36.
    González Sánchez, Pamela
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Deployment strategies in competitive wireless access networks2011In: Proceedings of the 1st International Conference on Advances in Cognitive Radio (COCORA), 2011Conference paper (Refereed)
  • 37.
    Grandhi, Sudheer A.
    et al.
    Wireless Inf. Network Lab., Rutgers University.
    Vijayan, Rajiv
    Wireless Inf. Network Lab., Rutgers University.
    Goodman, David J.
    Wireless Inf. Network Lab., Rutgers University.
    Zander, Jens
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Centralized Power Control in Cellular Radio Systems1993In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 42, no 4, 466-468 p.Article in journal (Refereed)
    Abstract [en]

    This paper describes a centralized power control scheme for cellular mobile radio systems. The power for the mobiles in the proposed scheme is computed based on signal strength measurements. All the mobiles using the same channel in this scheme will attain a common carrier-to-interference ratio. The proposed scheme is analyzed and shown to have an optimal solution.

  • 38.
    Grandhi, Sudheer A.
    et al.
    Wireless Inf. Network Lab., Rutgers University.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Constrained Power Control1994Report (Other academic)
  • 39.
    Grandhi, Sudheer A.
    et al.
    Wireless Inf. Network Lab., Rutgers University.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Constrained power control in cellular radio systems1994In: Vehicular Technology Conference, 1994, New York: IEEE , 1994, 824-828 p.Conference paper (Refereed)
    Abstract [en]

    High system capacities can be achieved by controlling the transmitter power in multiuser radio systems. Power control with no constraint on the maximum power level has been studied extensively in earlier work. Transmitter power is at a premium in radio systems such as cellular systems and PCS. There is a limit on the maximum transmitter power especially at the terminals (e.g. mobile units and handsets) since the power comes from a battery. In this paper we study power control that maximizes the minimum carrier to interference ratio (CIR), with a constraint on the maximum power. The optimal power vector solution lies on the boundary of the constrained power vector set and achieves a balance in the CIR's. Results indicate that the constraints do not induce any stability problems. A distributed scheme with favourable convergence properties and close to optimum performance is presented. Simulation results show that the algorithm tries to maximize the number of terminals served with CIR greater than or equal to the target CIR, while conserving power.

  • 40.
    Grandhi, Sudheer A.
    et al.
    Wireless Inf. Network Lab., Rutgers University.
    Zander, Jens
    KTH, Superseded Departments, Teleinformatics.
    Yates, Roy
    Wireless Inf. Network Lab., Rutgers University.
    Constrained Power Control1994In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 1, no 4, 257-270 p.Article in journal (Refereed)
    Abstract [en]

    High system capacities can be achieved by controlling the transmitter power in multiuser radio systems. Power control with no constraint on the maximum power level has been studied extensively in earlier work [1–18]. Transmitter power is at a premium in radio systems such as cellular systems and PCS. There is a limit on the maximum transmitter power especially at the terminals (e.g. mobile units and handsets) since the power comes from a battery. In this paper we study power control that maximizes the minimum carrier to interference ratio (CIR), with a constraint on the maximum power. The optimal power vector solution lies on the boundary of the constrained power vector set and achieves a balance in the CIR's. Results indicate that the constraints do not induce any stability problems. A distributed scheme with favourable convergence properties and close to optimum performance is presented. Simulation results show that the algorithm tries to maximize the number of terminals served with CIR greater than or equal to the target CIR, while conserving power.

  • 41. Han, S. -W
    et al.
    Kim, H.
    Han, Y.
    Cioff, J. M.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Leung, V. C. M.
    Distributed power allocation for cooperative access in cognitive radios to guarantee QoS for cell edge primary users2013In: Proceedings of 2013 6th Joint IFIP Wireless and Mobile Networking Conference, WMNC 2013, New York: IEEE , 2013, 6549027- p.Conference paper (Refereed)
    Abstract [en]

    Cognitive radio (CR) systems have been proposed for efficient usage of spare spectrum licensed to primary systems. This leads to the issue of providing as much spectrum to CR users as possible while not degrading the quality of service (QoS) of primary users of the spectrum. This paper proposes a novel cooperation scheme between primary and CR users to guarantee QoS of primary users up to the cell edge while making the licensed spectrum available for opportunistic access by the CR users. We suggest that the primary users at the cell edge, who have poor QoS, should allow secondary users to access their spectrum, while at the same time, the secondary users would help to enhance the primary users QoS using superposition coding on the primary users transmissions. Thus the proposed method can provide a so called 'win-win strategy' by benefiting both primary and CR users. The proposed cooperative access scheme in cognitive radios solves efficiently the sum-rate maximization problem on cognitive Gaussian Multiple Access Channels (GMACs) for power allocation of primary systems that cooperates with CR systems in a distributed fashion. We solved the problem using iterative Jacobian method in a distributed manner. Numerical results show that the QoS of primary users at the cell edge is improved by the proposed cooperative access scheme.

  • 42. Han, S. -W
    et al.
    Kim, H.
    Han, Y.
    Cioffi, J. M.
    Leung, V. C. M.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cooperative multiple access in cognitive radios to enhance QoS for cell edge primary users: asynchronous algorithm and convergence2016In: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 61, no 4, 631-643 p.Article in journal (Refereed)
    Abstract [en]

    Cognitive radio (CR) systems have been proposed for efficient usage of spare spectrum licensed to primary systems. This leads to the issue of providing as much spectrum to CR users as possible while not degrading the quality of service (QoS) of primary users of the spectrum. This paper proposes a novel cooperation scheme between primary and CR users to guarantee QoS of primary users up to the cell edge while making the licensed spectrum available for opportunistic access by the CR users. We suggest that the primary users at the cell edge, who have poor QoS, should allow secondary users to access their spectrum, while at the same time, the secondary users would help to enhance the primary users QoS using superposition coding on the primary users transmissions. Thus the proposed method can provide a so called “win-win strategy” by benefiting both primary and CR users. The proposed cooperative access scheme in cognitive radios solves efficiently the sum-rate maximization problem on cognitive Gaussian Multiple Access Channels (GMACs) for power allocation of primary systems that cooperates with CR systems in a distributed fashion. We solved the problem using iterative Jacobian method in a distributed manner. A totally asynchronous distributed power allocation for sum-rate maximization on cognitive GMACs is suggested. Numerical results show that the QoS of primary users at the cell edge is improved by the proposed cooperative access scheme.

  • 43.
    Han, Sang Wook
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Kim, R.
    Han, Y.
    Leung, V. C. M.
    Cioffi, J. M.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    An asynchronous distributed power allocation scheme for sum-rate maximization on cognitive GMACs2013In: Proceedings of 2013 6th Joint IFIP Wireless and Mobile Networking Conference, WMNC 2013, New York: IEEE , 2013, 6549031- p.Conference paper (Refereed)
    Abstract [en]

    This paper considers an asynchronous distributed power allocation scheme for sum-rate-maximization under cognitive Gaussian multiple access channels (GMACs), where primary users and secondary users may communicate under mutual interference with the Gaussian noise. Formulating the problem as a standard nonconvex quadratically constrained quadratic problem (QCQP) provides a simple distributed method to find a solution using iterative Jacobian method instead of using centralized schemes. A totally asynchronous distributed power allocation for sum-rate maximization on cognitive GMACs is suggested. Simulation results show that this distributed algorithm for power allocation converges to a fixed point and the solution achieves almost the same performance as exhaustive search.

  • 44.
    Hossain, Hossain Istiak
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    DERA: Augmented random access for cellular networks with dense H2H-MTC mixed traffic2017In: 2016 IEEE Globecom Workshops, GC Wkshps 2016 - Proceedings, 2017, 7848874Conference paper (Refereed)
    Abstract [en]

    In addition to the Mobile Broadband (MBB) services, future cellular networks will need to cope with a range of new "Internet of things" (IoT) services. LTE-Advanced and future generation cellular technologies should support both service sets within one network in order to keep the service costs and deployment expenses low. Massive IoT services require much less bandwidth than the MBB services, but the network need to serve a massive number of devices in each cell. The IoT applications put stringent demands on the service reliability and energy efficiency, and some will require very low delay. The existing random access (RA) procedures of cellular networks are not really designed for large numbers of terminals, which may result in excessive collisions, and hence, link delay and waste of precious battery energy. The present work aims at solving this problem by proposing a novel delay-estimation based random access scheme that improves the resolution mechanism of the conventional RA procedure in order to lower delay and energy consumption. The performance evaluation results show that the proposed scheme can significantly reduce the access delay in densely deployed scenarios.

  • 45.
    Hossain, Mohammad Istiak
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Markendahl, Jan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Enhanced Random Access: Initial access load balance in highly dense LTE-A networks for multiservice (H2H-MTC) traffic2017In: 2017 IEEE International Conference on Communications, ICC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, 7996622Conference paper (Refereed)
    Abstract [en]

    The Random Access (RA) procedure in existing cellular networks is not capable of functioning properly during high access load conditions. For this purpose, overload control mechanisms are needed. Most proposed mechanisms in the literature offer a tradeoff between access rate and experienced delay. However, when the maximal tolerated delay and the energy spent on retransmissions are tightly bounded, the very high access rate, targeted for 5G systems, cannot be achieved. For these situations, we propose the Delay Estimation based RA (DERA)-scheme that has the potential to meet very stringent reliability requirements, even in high access load conditions. The present work shows that this goal can be achieved only in the cost of limited additional complexity. Furthermore, we also study the optimal switchover point at which the proposed scheme moves from low-load to the high-load phase. The derived tool can also be used along with other proposed RA overload control schemes, e.g. when to invoke access class barring. The performance evaluation results show that the novel DERA scheme can significantly improve the control channels' resource utilization along with the success rate in dense deployment scenarios.

  • 46.
    Hossain, Mohammad Istiak
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Azari, Amin
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Markendahl, Jan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Enhanced Random Access:: Initial Access Load Balance in HighlyDense LTE-A Networks for Multiservice (H2H-MTC) Traffic2017Conference paper (Refereed)
    Abstract [en]

    The Random Access (RA) procedure in existing cellular networks is not capable of functioning properly during high access load conditions. For this purpose, overload control mechanisms are needed. Most proposed mechanisms in the literature offer a tradeoff between access rate and experienced delays. However, when the maximal tolerated delay and the energy spent on retransmissions are tightly bounded, the very high access rate, targeted for 5G systems, cannot be achieved. For these situations, we propose the Delay Estimation based RA (DERA)-scheme that has the potential to meet very stringent reliability requirements, even in high access load conditions. The present work shows that this goal can be achieved only at the cost of limited additional complexity. Furthermore, we also study the optimal switchover point at which the proposed scheme moves from low-load to the high-load phase. The derived tool can also be used along with other proposed RA overload control schemes, e.g.when to invoke access class barring. The performance evaluation results show that the novel DERA scheme can significantly improve the control channels’ resource utilization along with the success rate in dense deployment scenarios.

  • 47.
    Hultell, Johan
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Ileri, Ömer
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Communication Systems, CoS.
    Selfish users in energy constrained ALOHA systems with power capture2011In: Wireless networks, ISSN 1022-0038, E-ISSN 1572-8196, Vol. 17, no 1, 199-212 p.Article in journal (Refereed)
    Abstract [en]

    We consider a slotted ALOHA setting where backlogged, energy-constrained users selfishly select the probability with which they transmit packets. Packets are successfully received, even in case of collision, if the signal to interference plus noise ratio at the access point exceeds some threshold (power capture). The user problem of finding appropriate transmission probabilities is formulated as a static non-cooperative game and the performance limits for stationary and mobile scenarios are determined. The equilibrium analyses show that for stationary scenarios, users with high pathgains share the channel fairly while others never transmit. In the mobile case users utilize a binary strategy where they try to monopolize the channel when their pathgain exceeds some threshold that depends on system parameters (number of users, transmission costs, etc.). Otherwise they shut their transmitters off. Compared to traditional nondiscriminatory distributed multiaccess protocols the operating points achieved by selfish users generally increase sum-utility although this comes at the expense of larger user performance variations.

  • 48.
    Hultell, Johan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Service Provisioning with Ad-Hoc Deployed High-Speed Access Points in Urban environments2005In: 2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2005, IEEE conference proceedings, 2005, Vol. 3, 2019-2023 p.Conference paper (Refereed)
    Abstract [en]

     Exploiting user-deployed networks as part of a public infrastructure has been proposed as a concept to radically lower the cost of provisioning access and services in urban environments. An important question is how dense a network with spotty coverage has to be in order to support interesting services. In this paper1, we introduce a framework for evaluating the user-perceived performance for two service types, a time-critical news subscription service (involving streaming) and a more delay tolerant entertainment service ("web browsing"). The user terminals contain a memory cache and an "agent" that opportunistically downloads and stores relevant pieces of information as users walk close to the access points. Results show that above a critical access point density, that is still significantly lower than the one required for continuous coverage, the services start performing very well with little or no outdated information. In most studied scenarios, we are communication limited meaning that memory capacity is not a problem, but energy is.

  • 49.
    Hultell, Johan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Service Provisioning with Ad-hoc Deployed High-Speed Access Points in Urban Environments2005Conference paper (Refereed)
  • 50.
    Hultell, Johan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Markendahl, Jan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Competition and Cooperation in Wireless Multi-Access Networks2007In: Cognitive Wireless Networks: Concepts, Methodologies and Visions Inspiring the Age of Enlightenment of Wireless Communications / [ed] Frank H. P. Fitzek and Marcos D. Katz, Springer , 2007, 1, 109-132 p.Chapter in book (Refereed)
12345 1 - 50 of 221
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