| 1. |
- Blomgren, Mats, et al.
(författare)
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Decentralized market-based radio resource management in multi-network environments
- 2007
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Ingår i: IEEE VTS VEH TECHNOL CONF. - 9781424402656 ; , s. 2884-2889
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Konferensbidrag (refereegranskat)abstract
- For voice, an efficient radio resource management (RRM) essentially boils down to providing a predefined signal to interference ratio (SIR) at lowest cost possible and centralized schemes has, evidently, been an effective approach to address these problems. Delay-elastic data services, however, introduce both heterogeneous user requirements and possibilities for opportunistic RRM. One way, among others,to handle this would be to let autonomous trade-agents, acting on behalf of users, manage the radio resources, and this is our point of departure. We propose a market-based framework for decentralized RRM in environments populated by multiple, possibly heterogeneous, "access points" (APs), and the provided service for the users consists of file transfers. Resources (transmission time) are partitioned between users through a proportionally fair divisible auction. The problem at hand for the user (trade-agent), is then to determine how much resources it should purchase from the different APs in order to maximize its utility ("value for money"). Our results indicate that decentralized selfish bidding strategies are able to capitalize on temporary beneficial conditions and offer comparable performance with a centralized scheme (based on the 'mu C-rule') that requires knowledge about peak data-rates, queue lengths, and preferences for all users in the system.
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| 2. |
- Blomgren, Mats, et al.
(författare)
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Demand-responsive pricing in open wireless access markets
- 2007
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Ingår i: IEEE VTS VEH TECHNOL CONF. - 9781424402656 ; , s. 2990-2995
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Konferensbidrag (refereegranskat)abstract
- Radio resource management (RRM) across operator boundaries is emerging as a salient feature for wireless systems beyond 3G. Until recently, research has been confined to solutions where cooperating networks enter explicit sharing agreements that define how responsibilities and revenues should be divided. An alternative would be to share the infrastructure implicitly by establishing an open wireless access market wherein networks not only compete for users on a long-term time-scale, but also on a much shorter time-base. This could be realized with an architecture where autonomous trade-agents, that reside in terminals and access points (APs), manage the resources through negotiations. In this paper we develop a framework for studying demand-responsive pricing in contexts where APs with overlapping coverage compete for users. Resources are partitioned through a proportional fair divisible auction and our aim is to establish if, and when, an open market for wireless access can be se sustained. Compared to a scenario where APs cooperate, our results show that, an open access market results in better services at lower price which in the prolonging also yields more satisfied customers. As an effect demand will increase and, from the perspective of the APs, act as a counterbalance to the reduced prices. Thus, the revenue earned by the AN will be comparable to the one in which obtained through AP cooperation and monopoly (cartel) pricing. Generally speaking, the difference between the cooperative and noncooperative RRM is small when the demand is concave and increases with the convexity of demand.
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| 3. |
- Gomez-Barquero, David, et al.
(författare)
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Forward Error Correction for File Delivery in DVB-H
- 2007
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Ingår i: 2007 IEEE 65th Vehicular Technology Conference, Vols 1-6. - 9781424402656 ; , s. 2951-2955
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Konferensbidrag (refereegranskat)abstract
- Reliable filecasting to vehicular users in wireless broadcast networks is a very challenging task, as an error-free transmission of the files is required. Reliability can be achieved by means of forward error correction (FEC) and post-delivery file repair mechanisms. In this paper, we describe and compare the standardized FEC schemes in DVB-H (digital video broadcast-handheld) at the link and application layer, and evaluate their performance for file delivery to vehicular users. We show that by using application layer FEC it is possible to efficiently correct the errors appeared due to temporarily shadowing and fast fading, by taking advantage of the time and space diversity introduced by the bursty character of DVB-H transmissions and terminal mobility. Our results may constitute a valuable guide for operators when dimensioning their network capacity and service bandwidths, especially in the situations when vehicular users represent a large part of the customer base.
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| 4. |
- Johansson, Klas, et al.
(författare)
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Cost Efficient Deployment of Heterogeneous Wireless Access Networks
- 2007
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Ingår i: 2007 IEEE 65th Vehicular Technology Conference, Vols 1-6. - 9781424402656 ; , s. 3200-3204
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Konferensbidrag (refereegranskat)abstract
- As data applications become more popular in mobile networks, usage patterns will be different from mobile telephony. Demand for higher bit rates is found in certain areas ("hot spots"), whereas the requirement for wide area coverage remains. Previous work has shown that using classical cellular hot-spot techniques (e.g., micro-cells) with a single radio access technology imply high-cost solutions. Instead, combining several, carefully chosen, access technologies in an efficient manner, leads to reduced infrastructure related costs while retaining a sufficient quality of service. In this paper, we estimate the user data rates achievable by complementing an urban macro cellular high speed packet access (HSPA) system with different hot spot solutions. When deployed at comparable cost levels, "dense macro", micro, and pico HSPA base stations yield a similar performance in downlink. Thanks to more spectrum bandwidth, IEEE 802.11a WLAN supports higher data rates in downlink both on average and for the lower percentiles of users. For the uplink, which in principal is noise limited already with a few hot spots deployed, indoor (pico and WLAN) base stations outperform outdoor systems, which are subject to severe propagation losses for indoor users.
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| 5. |
- Larsson, Peter, 1966-
(författare)
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Joint power and rate control for delay tolerant traffic in a wireless system
- 2007
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Ingår i: 2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-6. - : IEEE. - 9781424402656 ; , s. 2822-2826
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Konferensbidrag (refereegranskat)abstract
- A power and rate control scheme especially crafted for delay tolerant traffic under interfering link conditions is presented in this paper. Specifically, an iterative distributed algorithm, based on a sum-power constrained sum-rate maximization with upper (and lower) power and rate constraints, is developed. The feasibility and performance of the algorithm is demonstrated by simulation in a cellular system, where it is applied both for SISO and MIMO links. Simulations show significant improvement of the sum-rate vs. sum-power relation compared to both HSDPA-like "fixed power adaptive rate" and GSM-like "fixed rate adaptive power" radio resource management. Also, the method offers automatic re-use handling by silencing sub-optimal links. In a MIMO scenario, the sum-rate scales near linearly with the number of antenna elements.
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| 6. |
- Lungaro, Pietro
(författare)
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Collaborative Information Revelation and Collusion in "Word-of Mouth" Access Selection Schemes
- 2007
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Ingår i: 2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE. - 9781424402656 ; , s. 282-286
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Konferensbidrag (refereegranskat)abstract
- "Word-of-Mouth", a novel scheme for sharing the service quality experienced with different local networks, is presented and evaluated as a distributed solution for performing user-initiated access selection in a multi-system scenario. If only partial information, about the different access alternatives, is available, by sharing and processing individually discovered information, terminal agents can collectively reveal otherwise concealed information and perform more informed access selection decisions. Introducing collusion mechanisms, between low performing networks and terminal agents, we investigate the robustness, of our distributed mechanism, to the dissemination of false information. In a scenario in which user-deployed APs have different degrees of backbone capacity limitation we investigate, if local operators can attract more traffic, by monetarily bribing terminal agents to transfer false information. Furthermore, we evaluate, under which conditions the prediction capability of our scheme can still support roaming access selection decisions that improve user service appreciation. The results show that if "enough" information, can be collected by independent sources, "economically rational" low performing APs can be effectively prevented from both concealing information and/or attempting to influence their reputation through collusive behavior.
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| 7. |
- Schwarzenbarth, Klaus, et al.
(författare)
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MMSE based interference processing for satellite broadcast reception
- 2007
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Ingår i: 2007 IEEE 65TH VEHICULAR TECHNOLOGY CONFERENCE. - : IEEE. - 9781424402656 ; , s. 1345-1349
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Konferensbidrag (refereegranskat)abstract
- The problem of Adjacent Satellite Interference (ACI) within the Direct-To-Home (DTH) satellite broadcast reception scenario is considered. The use of small DTH front-end reception systems results inevitably in a higher interference level from adjacent satellites using the same frequency band. The growth in satellite communication and the trend to small dishes increases the ACI problem. The general problem of interference limited DTH reception has been studied in recent work, see [2]. This paper extends the work of [21 by considering additionally an MMSE based method based on the proposal by Beidas and Gamal, see [3]. The interference channel model and the iterative interference cancellation algorithm are introduced and applied to the DTH digital broadcast case. Simulations of the interesting scenarios are conducted and discussed. It is shown, that the algorithm works well over large ranges of the considered scenarios of frequency offset and signal power levels.
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| 8. |
- Stabellini, Luca, et al.
(författare)
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Increasing system capacity in GERAN by means of TRX power reduction
- 2007
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Ingår i: 2007 IEEE Vehicular Technology Conference, Vols 1-6. - 9781424402656 ; , s. 1162-1166
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose an efficient and simple method to improve system capacity in GSM/GPRS/EDGE radio systems. It exploits the power shaping concept and the parameter "TRX power reduction" already present in the standard and does not require major modifications to operators specific radio resource management algorithms. Power-shaping means assigning in advance (static allocation) a maximum power level to each channel before dynamically performing channel allocation. This is done by exploiting a set of suitably reused power profiles that partially organize the inter-cell interference in the available channels and make it partially predictable. This technique, thanks to the possibility of tightening the reuse factor, permits to increase the system capacity for both voice and data services if compared to most common reuse schemes or to the widely used concentric cells schemes. This is shown in the results where an interesting gain is achieved by power shaping with power reduction with respect to the other schemes.
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