| 1. |
- Matthaiou, Michail, 1981, et al.
(författare)
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Novel Generic Bounds on the Sum Rate of MIMO ZF Receivers
- 2011
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Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 59:9, s. 4341-4353
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Tidskriftsartikel (refereegranskat)abstract
- This paper introduces some novel upper and lower bounds on the achievable sum rate of multiple-input multiple-output (MIMO) systems with zero-forcing (ZF) receivers. The presented bounds are not only tractable but also generic since they apply for different fading models of interest, such as uncorrelated/correlated Rayleigh fading and Ricean fading. We further formulate a new relationship between the sum rate and the first negative moment of the unordered eigenvalue of the instantaneous correlation matrix. The derived expressions are explicitly compared with some existing results on MIMO systems operating with optimal and minimum mean-squared error (MMSE) receivers. Based on our analytical results, we gain valuable insights into the implications of the model parameters, such as the number of antennas, spatial correlation and Ricean-K factor, on the sum rate of MIMO ZF receivers. RAMOWITZ M, 1970
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| 2. |
- Matthaiou, Michail, 1981, et al.
(författare)
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Sum Rate Analysis of ZF Receivers in Distributed MIMO Systems
- 2013
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Ingår i: IEEE Journal on Selected Areas in Communications. - 0733-8716 .- 1558-0008. ; 31:2, s. 180-191
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Tidskriftsartikel (refereegranskat)abstract
- The performance of single-cell distributed multiple-input multiple-output (D-MIMO) systems is not only affected by small-scale Rayleigh fading but also from large-scale fading and path-loss. In this paper, we elaborate on the sum rate of D-MIMO systems employing linear zero-forcing receivers, accounting for both large and small-scale fading effects, as well as spatial correlation at the transmit side. In particular, we consider the classical lognormal model and propose closed-form upper and lower bounds on the achievable sum rate. Using these bounds as a starting point, we pursue a "large-system" analysis and provide asymptotic expressions when the number of antennas at the base station (BS) grow large, and when the number of antennas at both ends grow large with a fixed and finite ratio. A detailed characterization in the asymptotically high and low signal to noise ratio regimes is also provided. An interesting observation from our results is that in order to maximize the sum rate, the RPs should be placed at unequal distances to the BS when they experience the same level of shadowing. The resulting closed-form expressions are compared with the corresponding results on MIMO optimal receivers.
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| 3. |
- Matthaiou, Michail, 1981, et al.
(författare)
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Sum rate analysis of ZF receivers in distributed MIMO systems with Rayleigh/Lognormal fading
- 2012
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Ingår i: IEEE International Conference on Communications. - 1550-3607. - 9781457720529 ; , s. 3857-3861
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Konferensbidrag (refereegranskat)abstract
- This paper presents a detailed sum rate characterization of distributed multiple-input multiple-output systems operating over composite fading channels and employing linear zero-forcing receivers. We consider the Rayleigh/Lognormal fading model and also take into account the effects of path-loss and spatial correlation at the transmit side. New closed-form upper and lower bounds on the achievable sum rate are proposed that apply for arbitrary numbers of antennas. Moreover, we investigate the concept of large-scale multiple-antenna systems when the number of receive antennas grow large. In this asymptotic regime, it is shown that the effects of Rayleigh fading are averaged out and the channel is dominated by the much more slowly varying shadowing. An interesting observation from our results is that in order to maximize capacity, the radio ports should be placed at unequal distances to the base station when they experience the same level of shadowing.
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| 4. |
- Matthaiou, Michail, 1981, et al.
(författare)
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Two Novel Upper Bounds on the Sum Rate of MIMO ZF Receivers
- 2011
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Ingår i: 54th Annual IEEE Global Telecommunications Conference (GLOBECOM), Houston, DEC 05-09, 2011. - 1930-529X. - 9781424492688
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Konferensbidrag (refereegranskat)abstract
- In this paper, we introduce two novel upper bounds on the achievable sum rate of multiple-input multiple-output (MIMO) systems with Zero-Forcing (ZF) receivers. The presented bounds are given in tractable closed-form and apply for different fading models, like uncorrelated/doubly correlated Rayleigh fading and Ricean fading. In addition, the first bound establishes an interesting relationship between the sum rate and the first negative moment of the unordered eigenvalue of the instantaneous correlation matrix. Based on our analytical expressions, we are able to explore the impact of the model parameters, such as number of antennas, spatial correlation and Ricean-K factor, on the sum rate of MIMO ZF receivers.
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| 5. |
- Xiao, Pei, et al.
(författare)
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Iterative Multi-User Detection and Decoding for DS-CDMA System with Space-Time Linear Dispersion
- 2009
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 58:5, s. 2343-2353
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers a Q-ary orthogonal DS-CDMA system with high rate space-time linear dispersion codes (LDC) in time-varying Rayleigh fading MIMO channels. We propose a joint multi-user detection, LDC decoding, Q-ary demodulation and channel decoding algorithm and apply turbo processing principle to improve the system performance in an iterative fashion. The proposed iterative scheme demonstrates faster convergence and superior performance (especially at low SNRs) compared to the V-BLAST based DS-CDMA system, and is shown to approach the single-user performance bound. The gain is more significant when the LDC decoding and symbol demodulation is assisted by a decision-directed multi-user detection technique. We also show that the CDMA system is able to exploit the time diversity offered by the LDCs in fast fading channels.
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| 6. |
- Zhong, C. J., et al.
(författare)
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Generic Ergodic Capacity Bounds for Fixed-Gain AF Dual-Hop Relaying Systems
- 2011
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Ingår i: IEEE Transactions on Vehicular Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9545 .- 1939-9359. ; 60:8, s. 3814-3824
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Tidskriftsartikel (refereegranskat)abstract
- This paper elaborates on the ergodic capacity of fixed-gain amplify-and-forward (AF) dual-hop systems, which have recently attracted considerable research and industry interest. In particular, two novel capacity bounds that allow for fast and efficient computation and apply for nonidentically distributed hops are derived. More importantly, they are generic since they apply to a wide range of popular fading channel models. Specifically, the proposed upper bound applies to Nakagami-m, Weibull, and generalized-K fading channels, whereas the proposed lower bound is more general and applies to Rician fading channels. Moreover, it is explicitly demonstrated that the proposed lower and upper bounds become asymptotically exact in the high signal-to-noise ratio (SNR) regime. Based on our analytical expressions and numerical results, we gain valuable insights into the impact of model parameters on the capacity of fixed-gain AF dual-hop relaying systems.
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