| 1. |
- Keykhosravi, Kamran, et al.
(författare)
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Leveraging Ris-Enabled Smart Signal Propagation for Solving Infeasible Localization Problems
- 2023
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Ingår i: IEEE Vehicular Technology Magazine. - 1556-6080 .- 1556-6072. ; 18:2, s. 20-28
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Tidskriftsartikel (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) have tremendous potential for both communication and localization. While communication benefits are now well understood, the breakthrough nature of the technology may well lie in its capability to provide and support localization capabilities. We present an overview of RIS-enabled localization scenarios, considering various numbers of RISs, single- or multi-antenna base stations, narrowband or wideband transmissions, and near- and far-field operations. Based on this overview, we also highlight key research directions and open challenges specific to RIS-enabled localization and sensing.
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| 2. |
- Abbasi, Muhammad Ali Babar, et al.
(författare)
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Aggressive RF Circuit Reduction Techniques in Millimeter Wave Cellular Systems
- 2019
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Ingår i: 2019 16th International Symposium on Wireless Communication Systems (ISWCS). - 9781728125275
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Konferensbidrag (refereegranskat)abstract
- In this paper, we introduce a novel hybrid multiuser multiple-input multiple-output (MU-MIMO) architecture, with an emphasis on aggressive millimeter-wave (mmWave) hardware reduction methods, omitting the beam selection stage. We propose a simplification in a 28 GHz Rotman lens, where the number of beam-ports are reduced relative to the array ports resulting in the removal of a bank of RF switches and its associated biasing network. We conducted full electromagnetic characterization of imperative lens defects and precisely quantify the expected loss. For the first time, it is shown that the beam-port decimation greatly reduces the total EM aberrations, and consequently increases the focusing capability of the lens. With maximum-ratio (MR) baseband processing, we study uplink signal-to-interference-plus-noise ratio (SINR) of a user terminal, and evaluate the sum spectral efficiency performance of the proposed system assuming a 28 GHz double-directional propagation channel. The performance of the proposed system is compared with the classical system include the beam selection network. Although the performance of the proposed architecture is sub-optimal relative to the conventional case, we demonstrate that it greatly simplifies the practical realizations of the mmWave RF front-ends, while still maintaining highly desirable and useful operational characteristics.
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| 3. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Cognitive Amplify-and-Forward Relaying with Best Relay Selection in Non-Identical Rayleigh Fading
- 2013
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Ingår i: IEEE Communications Letters. - : IEEE. - 1089-7798 .- 1558-2558. ; 17:3, s. 475-478
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates several important performance metrics of cognitive amplify-and-forward (AF) relay networks with a best relay selection strategy and subject to nonidentical Rayleigh fading. In particular, assuming a spectrum sharing environment consists of one secondary user (SU) source,K SU relays, one SU destination, and one primary user (PU) receiver, closed-form expressions for the outage probability (OP), average symbol error probability (SEP), and ergodic capacity of the SU network are derived. The correctness of the proposed analysis is corroborated via Monte Carlo simulations and readily allows us to evaluate the impact of the key system parameters on the end-to-end performance. An asymptotic analysis is also carried out and reveals that the diversity gain is defined by the number of relays pertaining to the SU network (i.e., K), being therefore not affected by the interference power constraint of the PU network.
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| 4. |
- Duong, Quang Trung, et al.
(författare)
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Cooperative spectrum sharing networks with AF relay and selection diversity
- 2011
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology - IET. - 0013-5194 .- 1350-911X. ; 47:20, s. 1149-1151
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Tidskriftsartikel (refereegranskat)abstract
- The exact outage probability (OP) of cognitive dual-hop relay networks equipped with a single amplify-and-forward (AF) relay and a selection combining receiver at the destination is derived under spectrum sharing constraint on a primary user. The tractable closed-form OP readily enables evaluation of system performance, which indicates the significance of using a relay in cognitive radio networks with a spectrum sharing approach. The proposed analysis is validated by numerical examples.
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| 5. |
- Duong, Quang Trung, et al.
(författare)
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Effect of primary network on performance of spectrum sharing AF relaying
- 2012
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Ingår i: Electronics Letters. - : IET. - 0013-5194 .- 1350-911X. ; 48:1, s. 25-U95
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Tidskriftsartikel (refereegranskat)abstract
- Most of the research in spectrum sharing has neglected the effect of interference from primary users. In this reported work, the performance of spectrum sharing amplify-and-forward relay networks under interference-limited environment, where the interference induced by the transmission of primary networks is taken into account, is investigated. In particular, a closed-form expression tight lower bound of outage probability is derived. To reveal additional insights into the effect of primary networks on the diversity and array gains, an asymptotic expression is also obtained.
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| 6. |
- Duong, Quang Trung, et al.
(författare)
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Orthogonal Space-Time Block Codes with CSI-Assisted Amplify-and-Forward Relaying in Correlated Nakagami-m Fading Channels
- 2011
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Ingår i: IEEE Transactions on Vehicular Technology. - : IEEE. - 0018-9545 .- 1939-9359. ; 60:3, s. 882-889
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the performance of multiple-input multiple-output (MIMO) dual-hop amplify-and-forward (AF) relay systems using orthogonal space-time block codes (OSTBCs) over arbitrarily correlated Nakagami-m fading channels is analyzed. In particular, closed-form expressions for the end-to-end outage probability (OP) and the symbol error probability (SEP) with arbitrary number of transceiver antennas and general correlation matrices are derived. Their mathematically tractable forms readily enable us to evaluate the performance of MIMO AF relay systems that utilize OSTBCs. For sufficiently high signal-to-noise ratios, asymptotically tight approximations for the OP and SEP are also attained which reveal insights into the effects of fading parameters and antenna correlation on the system’s performance. Furthermore, we prove that the correlation has no impact on the achievable diversity gain which is equal to the minimum of the sum of fading parameters between the two hops. Selected numerically evaluated results are presented showing an excellent agreement between the proposed analysis and equivalent Monte-Carlo simulations.
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| 7. |
- Duong, Quang Trung, et al.
(författare)
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Outage probability of MIMO AF relay networks over Nakagami-m fading channels
- 2010
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Ingår i: Electronics Letters. - : The Institution of Engineering and Technology. - 0013-5194 .- 1350-911X. ; 46:17
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Tidskriftsartikel (refereegranskat)abstract
- The outage probability (OP) of multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay networks using orthogonal space-time block code is investigated. In particular, a closed-form tight lower bound expression for the OP over independently but not necessarily identically distributed Nakagami-m fading channels is derived. Moreover, an asymptotic approximation for OP which reveals the coding and diversity gains is presented. The analytical expressions are validated by Monte-Carlo simulations.
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| 8. |
- Matthaiou, Michail, et al.
(författare)
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Analytic framework for the effective rate of MISO fading channels
- 2012
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Ingår i: IEEE Transactions on Communications. - : IEEE Communications Society. - 0090-6778 .- 1558-0857. ; 60:6, s. 1741-1751
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Tidskriftsartikel (refereegranskat)abstract
- The delay constraints imposed by future wireless applications require a suitable metricfor assessing their impact on the overall system performance. Since the classical Shannon's ergodic capacityfails to do so, the so-called effective rate was recently established as a rigorous alternative. While prior relevant works have improved our knowledge on the effective rate characterization of communication systems, an analytical framework encompassing several fading models of interest isnot yet available. In this paper, we pursue a detailed effective rate analysis of Nakagami-m, Ricianand generalized-K multiple-input single-output (MISO) fading channels by deriving new, analytical expressions for their exact effective rate. Moreover, we consider the asymptotically low and high signal-to-noise (SNR) regimes, for which tractable, closed-form effective rate expressions are presented. These results enable us to draw useful conclusions about the impact of system parameters on the effective rate of different MISO fading channels. All the theoretical expressions are validated via Monte-Carlo simulations.
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| 9. |
- Matthaiou, Michail, 1981, et al.
(författare)
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Effective Rate Analysis of MISO Rician Fading Channels
- 2012
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Ingår i: Proccedings of the 2012 IEEE 7th Sensor Array and Multichannel Signal Processing Workshop (SAM), June 17-20, 2012 in Hoboken, NJ, USA. - : IEEE. - 2151-870X. - 9781467310710 ; , s. 53-56
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Konferensbidrag (refereegranskat)abstract
- The delay constraints imposed by future wirelessapplications require a suitable metric for assessing their impacton the overall system performance. Since the classical Shannon’s ergodic capacity fails to do so, the so-called effective rate was recently established as a rigorous alternative. Yet, most priorrelevant works have considered only the typical case of Rayleighfading which allows for tractable manipulations. In this paper,we relax this assumption by considering the more general Rician fading model for multiple-input single-output (MISO) systems. Anew, analytical expression for the exact effective rate is derived, along with tractable expressions for the key parameters dictating the effective rate performance in the high and low signal-to-noise(SNR) regimes.
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| 10. |
- Mishra, Deepak, 1990-, et al.
(författare)
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Energy-Aware mode selection for throughput maximization in RF-Powered D2D Communications
- 2018
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Ingår i: GLOBECOM 2017 - 2017 IEEE Global Communications Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509050192 - 9781509050208 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Doubly-near-far problem in RF-powered networks can be mitigated by choosing appropriate device-To-device (D2D) communication mode and implementing energy-efficient information transfer (IT). In this work, we present a novel RF energy harvesting architecture where each transmitting-receiving user pair is allocated a disjoint channel for its communication which is fully powered by downlink energy transfer (ET) from hybrid access point (HAP). Considering that each user pair can select either D2D or cellular mode of communication, we propose an optimized transmission protocol controlled by the HAP that involves harvested energy-Aware jointly optimal mode selection (MS) and time allocation (TA) for ET and IT to maximize the sum-Throughput. Jointly global optimal solutions are derived by efficiently resolving the combinatorial issue with the help of optimal MS strategy for a given TA for ET. Closed-form expressions for the optimal TA in D2D and cellular modes are also derived to gain further analytical insights. Numerical results show that the joint optimal MS and TA, which significantly outperforms the benchmark schemes in terms of achievable RF-powered sum-Throughput, is closely followed by the optimal TA scheme for D2D users. In fact, about 2/3 fraction of the total user pairs prefer to follow the D2D mode for efficient RF-powered IT.
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