| 1. |
- Abrardo, Andrea, et al.
(författare)
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Distributed Digital and Hybrid Beamforming Schemes With MMSE-SIC Receivers for the MIMO Interference Channel
- 2019
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Ingår i: IEEE Transactions on Vehicular Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9545 .- 1939-9359. ; 68:7, s. 6790-6804
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the problem of weighted sumrate maximization and mean squared error (MSE) minimization for the multiple-input multiple-output (MIMO) interference channel. Specifically, we consider a weighted minimum MSE architecture where each receiver employs successive interference cancellation (SIC) to separate the various received data streams and derive a hybrid beamforming scheme, where the transmitters operate with a number of radio frequency chains smaller than the number of antennas, particularly suited for millimeter-wave channels and 5G applications. To derive our proposed schemes, we first study the relationship between sum-rate maximization and weighted MSE minimization when using SIC receivers, assuming fully digital beamforming. Next, we consider the important-and, as it turns out, highly non-trivial-case where the transmitters employ hybrid digital/analog beamforming, developing a distributed joint hybrid precoding and SIC-based combining algorithm. Moreover, for practical implementation, we propose a signaling scheme that utilizes a common broadcast channel and facilitates the acquisition of channel state information, assuming minimal assistance from a central node such as a cellular base station. Numerical results show that both the proposed weighted MMSE-SIC schemes exhibit great advantages with respect to their linear counterparts in terms of complexity, feedback information, and performance.
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| 2. |
- Abrardo, Andrea, et al.
(författare)
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MMSE Receiver Design and SINR Calculation in MU-MIMO Systems With Imperfect CSI
- 2019
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Ingår i: IEEE Wireless Communications Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 2162-2337 .- 2162-2345. ; 8:1, s. 269-272
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Tidskriftsartikel (refereegranskat)abstract
- The performance of the uplink of multiuser multiple input multiple output systems depends critically on the receiver architecture and on the quality of the acquired channel state information. A popular approach is to design linear receivers that minimize the mean squared error (MSE) of the received data symbols. Unfortunately, most of the literature does not take into account the presence of channel state information errors in the MSE minimization. In this letter we develop a linear minimum MSE (MMSE) receiver that employs the noisy instantaneous channel estimates to minimize the MSE, and highlight the dependence of the receiver performance on the pilot-to-data power ratio. By invoking the theory of random matrices, we calculate the users' signal-to-interference-plus-noise ratio as a function of the number of antennas and the pilot-to-data power ratio of all users. Numerical results indicate that this new linear receiver outperforms the classical mismatched MMSE receiver.
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| 3. |
- Belleschi, Marco, et al.
(författare)
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Benchmarking Practical RRM Algorithms for D2D Communications in LTE Advanced
- 2014
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Ingår i: Wireless personal communications. - : Springer. - 0929-6212 .- 1572-834X. ; 82:2, s. 883-910
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Tidskriftsartikel (refereegranskat)abstract
- Device-to-device (D2D) communication integrated into cellular networks is an advanced tool to take advantage of the proximity of devices and allow for reusing cellular resources and thereby to increase the user bitrates and the system capacity. However, the introduction of D2D in legacy long term evolution (LTE) cellular spectrum requires to revisit and modify the existing radio resource management and power control (PC) techniques in order to fully realize the potential of the proximity and reuse gains and to limit the interference to the cellular layer. In this paper, we examine the performance of the legacy LTE PC tool box and benchmark it against an utility optimal iterative scheme. We find that the open loop PC scheme of LTE performs well for cellular users both in terms of the used transmit power levels and the achieved signal-to-interference-and-noise-ratio distribution. However, the performance of the D2D users as well as the overall system throughput can be boosted by the utility optimal scheme, by taking better advantage of both the proximity and the reuse gains. Therefore, in this paper we propose a hybrid PC scheme, in which cellular users employ the legacy LTE open loop PC, while D2D users exploits the utility optimizing distributed PC scheme. We also recognize that the hybrid scheme is not only nearly optimal, and can balance between spectral and energy efficiency, but it also allows for a distributed implementation at the D2D users, while preserving the LTE PC scheme for the cellular users.
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| 4. |
- Belleschi, Marco, et al.
(författare)
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Fast power control for cross-layer optimal resource allocation in DS-CDMA wireless networks
- 2009
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Ingår i: 2009 IEEE International Conference on Communications. ; , s. 4341-4346
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel cross-layer design for joint power and end-to-end rate control optimization in DS-CDMA wireless networks, along with a detailed implementation and evaluation in the network simulator ns-2. Starting with a network utility maximization formulation of the problem, we derive distributed power control, transport rate and queue management schemes that jointly achieve the optimal network operation. Our solution has several attractive features compared to alternatives: it adheres to the natural time-scale separation between rapid power control updates and slower end-to-end rate adjustments, and uses simplified power control mechanisms with reduced signalling requirements. We argue that these features are critical for a successful real-world implementation. To validate these claims, we present a detailed implementation of a crosslayer adapted networking stack for DS-CSMA ad-hoc networks in ns-2. We describe several critical issues that arise in the implementation, but are typically neglected in the theoretical protocol design, and evaluate the alternatives in extensive simulations.
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| 5. |
- Della Penda, Demia, et al.
(författare)
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Distributed Channel Allocation for D2D-Enabled 5G Networks Using Potential Games
- 2019
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 7, s. 11195-11208
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Tidskriftsartikel (refereegranskat)abstract
- Frequency channel allocation is a key technique for improving the performance of cellular networks. In this paper, we address the channel allocation problem for a 5G multi-cell system. We consider a heterogeneous network in which cellular users, micro-cell users, and device-to-device (D2D) communications coexist within the radio footprint of the macro cell. We maximize the aggregate transmission rate, exploiting channel diversity and managing both the inter-cell interference, typical of cellular networks and the intra-cell interference generated by the nonorthogonal transmissions of the small-cell and D2D users. By modeling the allocation problem as a potential game, whose Nash equilibria correspond to the local optima of the objective function, we propose a new decentralized solution. The convergence of our scheme is enforced by using a better response dynamic based on a message passing approach. The simulation results assess the validity of the proposed scheme in terms of convergence time and achievable rate under different settings.
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| 6. |
- Della Penda, Demia, et al.
(författare)
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Potential games for subcarrier allocation in multi-cell networks with D2D communications
- 2016
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Ingår i: 2016 IEEE International Conference Communications (ICC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479966646
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the subcarrier allocation problem for uplink transmissions in a multi-cell network, where device-to-device communications are enabled. We focus on maximizing the aggregate transmission rate in the system accounting for both inter- and intra-cell interference. This problem is computationally hard due to its nonconvex and combinatorial nature. However, we show that it can be described by a potential game, and thus a Nash equilibrium can be found using iterative algorithms based on best/better response dynamics. In particular, we propose a simple iterative algorithm with limited signaling that is guaranteed to converge to an equilibrium point, corresponding to a local maximum of the potential function. Using extensive simulations, we show that the algorithm converges quickly also for dense networks, and that the distance to the true optimum is often small, at least for the small-sized networks for which we were able to compute the true optimum.
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| 7. |
- Fodor, Gabor, 1964-, et al.
(författare)
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A Joint Power Control and Resource Allocation Algorithm for D2D Communications
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We consider the problem of joint power control, signal-to-noise-and-interference-ratio (SINR)target setting, mode selection and resource allocation for cellular network assisteddevice-to-device (D2D) communications.This problem is important for fourth generation systems, such as the release under study of the Long TermEvolution Advanced (LTE-A) system standardized by the Third Generation Partnership Project (3GPP).While previous works on radio resource management (RRM) algorithms for D2D communications dealt withmode selection and power control, the problem of resource allocation for the integrated cellular-D2Denvironment and in particularthe joint problem of mode selection, resource allocation and power allocation has not been addressed.We propose a utility function maximization approach that allows to take into account the inherenttrade off between maximizing spectrum efficiency and minimizing the required sum transmit power.We implement the proposed RRM algorithms in a realistic system simulator and report numericalresults that indicate large gains of D2D communications both in terms of spectrum- and energyefficiency.
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| 8. |
- Jiang, Fan, 1987-, et al.
(författare)
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Two-Timescale Transmission Design and RIS Optimization for Integrated Localization and Communications
- 2023
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Ingår i: IEEE Transactions on Wireless Communications. - Piscataway : IEEE. - 1536-1276 .- 1558-2248. ; 22:12, s. 8587-8602
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Tidskriftsartikel (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) have tremendous potential to boost communication performance, especially when the line-of-sight (LOS) path between the user equipment (UE) and base station (BS) is blocked. To control the RIS, channel state information (CSI) is needed, which entails significant pilot overhead. To reduce this overhead and the need for frequent RIS reconfiguration, we propose a novel framework for integrated localization and communications, where RIS configurations are fixed during location coherence intervals, while BS precoders are optimized every channel coherence interval. This framework leverages accurate location information obtained with the aid of several RISs as well as novel RIS optimization and channel estimation methods. Performance in terms of localization accuracy, channel estimation error, and achievable rate demonstrates the effectiveness of the proposed approach. © 2023 IEEE.
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| 9. |
- Jiang, Fan, 1987, et al.
(författare)
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Two-Timescale Transmission Design and RIS Optimization for Integrated Localization and Communications
- 2023
-
Ingår i: IEEE Transactions on Wireless Communications. - 1558-2248 .- 1536-1276. ; 22:12, s. 8587-8602
-
Tidskriftsartikel (refereegranskat)abstract
- Reconfigurable intelligent surfaces (RISs) have tremendous potential to boost communication performance, especially when the line-of-sight (LOS) path between the user equipment (UE) and base station (BS) is blocked. To control the RIS, channel state information (CSI) is needed, which entails significant pilot overhead. To reduce this overhead and the need for frequent RIS reconfiguration, we propose a novel framework for integrated localization and communications, where RIS configurations are fixed during location coherence intervals, while BS precoders are optimized every channel coherence interval. This framework leverages accurate location information obtained with the aid of several RISs as well as novel RIS optimization and channel estimation methods. Performance in terms of localization accuracy, channel estimation error, and achievable rate demonstrates the effectiveness of the proposed approach.
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