| 1. |
- Beygi, Lotfollah, 1977, et al.
(författare)
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A novel multilevel coded modulation scheme for fiber optical channel with nonlinear phase noise
- 2010
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Ingår i: Proc. Global Communications Conference, Miami, FL. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- A multilevel coded modulation (MLCM) system in the presence of nonlinear phase noise for fiber optical communication is introduced. The proposed scheme exploits a 16-point ring constellation with nonlinear post compensation of the self phase modulation produced via the Kerr effect. A new set partitioning based on the Ungerboeck approach is introduced to maintain unequal error protection in amplitude and phase direction. The rate allocation for the MLCM component codes for different fiber lengths and transmit powers are done numerically. Simulation results show that the proposed MLCM system provides up to 2 dB gain over a forward error correcting scheme for a block error rates around 10-9, with the same overhead (7%) and complexity. ©2010 IEEE.
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| 2. |
- Björnson, Emil, 1983-, et al.
(författare)
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Optimality Properties and Low-Complexity Solutions to Coordinated Multicell Transmission
- 2010
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Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - : IEEE. - 9781424456383 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Base station cooperation can theoretically improve the throughput of multicell systems by coordinating interference and serving cell edge terminals through multiple base stations. In practice, the extent of cooperation is limited by the increase in backhaul signaling and computational demands. To address these concerns, we propose a novel distributed cooperation structure where each base station has responsibility for the interference towards a set of terminals, while only serving a subset of them with data. Weighted sum rate maximization is considered, and conditions for beamforming optimality and the optimal transmission structure are derived using Lagrange duality theory. This leads to distributed low-complexity transmission strategies, which are evaluated on measured multiantenna channels in a typical urban multicell environment.
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| 3. |
- Caceres, M.A., et al.
(författare)
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Hybrid GNSS-terrestrial cooperative positioning via distributed belief propagation
- 2010
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Ingår i: GLOBECOM - IEEE Global Telecommunications Conference. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- Cooperative positioning algorithms have been recently introduced to overcome the limitations of traditional methods, relying on GNSS or other terrestrial infrastructure. In particular, SPAWN (Sum-Product Algorithm over a Wireless Network) was shown to provide accurate position estimate even in challenged indoor environments, thanks to exchange of local information among peers based on terrestrial ranging. In this paper we extend the SPAWN framework by considering a hybrid scenario, where agents combine satellite and peer-to-peer terrestrial measurements. The novel hybrid SPAWN (H-SPAWN) approach allows increased availability and robustness compared to GNSS-only positioning in light and deep indoor scenarios, while keeping the advantages of a distributed implementation of the original SPAWN. A parametric message representation is proposed to reduce the communication overhead, and to improve the estimation accuracy. Simulation results show that the proposed solution outperforms traditional algorithms such as cooperative least squares and the extended Kalman filter.
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| 4. |
- de Kerret, Paul, et al.
(författare)
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Analytic framework for the mutual information cumulants of different MIMO channels
- 2010
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Ingår i: 53rd IEEE Global Communications Conference, GLOBECOM 2010; Miami, FL; United States; 6 December 2010 through 10 December 2010. - 9781424456383 ; , s. Art. no. 5683814-
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a general analytical framework for the exact mutual information (MI) cumulants of multiple-input multiple-output (MIMO) systems with perfect receiver channel state information (CSI) and no transmitter CSI. Our derivation is based on a recent parameterization of the joint ordered eigenvalue probability density function (PDF) [1], that encompasses both uncorrelated/semi-correlated Rayleigh channels as well as uncorrelated Rician channels. In addition, we extend our framework to account for the cumulants of doubly-correlated Rayleigh channels and also to deduce tractable expressions in the high Signal-to-Noise ratio (SNR) regime. The cumulants are particularly useful to study all high-order statistics (HOS) of the MI; in fact, they can be used to express the MI mean and variance as a finite sum of determinants. Our analytical expressions are then validated via Monte-Carlo simulations with the attained accuracy being excellent in all cases.
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| 5. |
- Di Marco, Piergiuseppe, et al.
(författare)
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Analytical Modelling of IEEE 802.15.4 for Multi-hop Networks with Heterogeneous Traffic and Hidden Terminals
- 2010
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Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- IEEE 802.15.4 multi-hop wireless networks are an important communication infrastructure for many applications, including industrial control, home automation, and smart grids. Existing analysis of the IEEE 802.15.4 medium access control (MAC) protocol are often based on assumptions of homogeneous traffic and ideal carrier sensing, which are far from the reality when predicting performance for multi-hop networks. In this paper, a generalized analysis of the unslotted IEEE 802.15.4 MAC is presented. The model considers heterogeneous traffic and hidden terminals due to limited carrier sensing capabilities, and allows us to investigate jointly IEEE 802.15.4 MAC and routing algorithms. The analysis is validated via Monte Carlo simulations, which show that routing over multi-hop networks is significantly influenced by the IEEE 802.15.4 MAC performance. Routing decisions based on packet loss probability may lead to an unbalanced distribution of the traffic load across paths, thus motivating the need of a joint optimization of routing and MAC.
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| 6. |
- Haghighi, Kasra, 1978, et al.
(författare)
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Wideband Sequential Spectrum Sensing with Varying Thresholds
- 2010
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Ingår i: Proceedings IEEE Global Communications Conference, Wireless Communications Symposium, Miami, Florida, USA. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- In this contribution, time varying threshold sequentialdetectors are employed for energy detection-based spectrumsensing in low-SNR regimes. Sequential detection is proven to befaster (on average) than any other multi-sample detector for a setof given probabilities of detection and false-alarm. In this report,exact performance of a sequential detector for spectrum sensingis analyzed using the direct method. The theoretical resultspresented herein are verified with Monte-Carlo simulations. Itis shown that for a SNR of −10 dB, among tests with Wald andtriangular thresholds with similar probabilities of mis-detectionand false-alarm, triangular performs 54% faster in terms ofmaximum detection time (90 percentile).
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| 7. |
- Muhammad, Ajmal, et al.
(författare)
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Energy-Efficient WDM Network Planning with Dedicated Protection Resources in Sleep Mode
- 2010
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Ingår i: Global Telecommunications Conference (GLOBECOM 2010), 2010 IEEE. - : IEEE. - 9781424456383 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- Energy-efficient optical networks are gaining momentum as environmental-friendly solutions with reduced operational costs. Energy-efficiency can be achieved by using devices in sleep mode, i.e., a low-power, inactive state in which devices can be suddenly waken-up upon occurrence of triggering events. This paper advocates a sleep mode option for the optical devices (e.g., amplifiers, optical switches) installed for protection purposes only. These devices can be put in sleep mode to reduce the network power consumption, but they can be promptly waken up (if necessary) upon a failure occurrence. This principle is proposed and applied in Wavelength Division Multiplexing (WDM) networks with dedicated-path protection to ensure survivability against single-link failures. The main contribution of the paper is the definition of the energy-efficient network planning problem for resilient WDM networks where optical devices can be configured in sleep mode. Optimal results of the integer linear programming (ILP) problem show savings of up to 25% in the overall power consumption.
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| 8. |
- Schrammar, Nicolas, et al.
(författare)
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Transmission Strategies for Gaussian Relay Networks Obtained from Deterministic Models
- 2010
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Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - : IEEE conference proceedings. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- A constant gap between the deterministic model of a class of a wireless relay network and its Gaussian model counterpart is derived. The method is constructive in the sense that a transmission solution in the deterministic model that obeys certain constraints can directly be translated into a transmission in the Gaussian model. We show that the rate in the Gaussian model is at most a constant gap below the rate in the deterministic model, and we derive an upper bound on this gap.
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| 9. |
- Soldati, Pablo, et al.
(författare)
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Optimal Routing and Scheduling of Deadline-Constrained Traffic Over Lossy Networks
- 2010
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Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- The traditionally wired automation infrastructure is quickly migrating to more flexible and scalable wireless solutions. To cope with the stringent requirements of process automation in terms of latency and reliability, the network resources must be optimized to ensure timely and reliable communication. This paper considers the joint routing and transmission scheduling problem for reliable real-time communication over lossy networks. Specifically, we impose a strict latency bound for packet delivery from source to destination, and devise optimal transmission scheduling policies that maximize the success probability of delivering the packet within the specified deadline. A solution to this problem allows to characterize the set of achievable latencies and packet reliability for a given network. We offer a complete understanding of the problem when erasure events on links are independent and follow a Bernoulli process. We consider both static and dynamic resource allocation policies, and compare them in numerical examples.
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| 10. |
- Stala, Michal, et al.
(författare)
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Hardware Implementation of an Iterative Sampling Rate Converter for Wireless Communication
- 2010
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Ingår i: IEEE Global Telecommunications Conference (Globecom). - 1930-529X. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined This paper presents a new technique for fractional sample rate conversion based on an iterative Sinc (ISRC) method. The proposed algorithm was evaluated against the Farrow re-sampler, and performance simulation targeting different signal-to-noise ratios show the ISRC qualifies for application in reconfigurable terminals. The architecture was implemented in 65nm CMOS technology, and synthesis results show that the ISRC requires at least 23% less silicon area, compared to a Farrow filter with similar performance. The generic nature of the architecture enables further area reduction by time-multiplexing.
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