| 1. |
- Kapetanovic, Dzevdan, et al.
(författare)
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Lattice Structures of Precoders Maximizing the Minimum Distance in Linear Channels
- 2015
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448 .- 1557-9654. ; 61:2, s. 908-916
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates linear precoding over nonsingular linear channels with additive white Gaussian noise, with lattice-type inputs. The aim is to maximize the minimum distance of the received lattice points, where the precoder is subject to an energy constraint. It is shown that the optimal precoder only produces a finite number of different lattices, namely perfect lattices, at the receiver. The well-known densest lattice packings are instances of perfect lattices, but are not always the solution. This is a counter-intuitive result as previous work in the area showed a tight connection between densest lattices and minimum distance. Since there are only finite many different perfect lattices, they can theoretically be enumerated offline. A new upper bound on the optimal minimum distance is derived, which significantly improves upon a previously reported bound, and is useful when actually constructing the precoders.
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| 2. |
- Rusek, Fredrik, et al.
(författare)
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Bounds on the Information Rate of Intersymbol Interference Channels Based on Mismatched Receivers
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 58:3, s. 1470-1482
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Tidskriftsartikel (refereegranskat)abstract
- We consider the problem of bounding the information rate of intersymbol interference channels via simulation-based algorithms. The adopted approach, which is based on a general class of reduced-complexity receivers that includes several previously studied receivers as special cases, leads to provable upper and lower bounds on the information rate of interest. As a by-product of the information-theoretic investigations, novel insights on the design of efficient reduced-complexity receivers are also provided, since the proposed lower bounds are known to be achievable by practical receivers. In many scenarios, our novel approach significantly outperforms the existing ones, for all practical values of the signal-to-noise ratio.
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| 3. |
- Rusek, Fredrik, et al.
(författare)
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Constrained capacities for faster-than-Nyquist signaling
- 2009
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 55:2, s. 764-775
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with capacity computations of faster-than-Nyquist (FTN) signaling. It shows that the capacity of FTN is higher than the orthogonal pulse linear modulation capacity for all pulse shapes except the sinc. FTN signals can in fact achieve the ultimate capacity for the signal power spectral density (PSD). The paper lower and upper bounds the FTN capacity under the constraint of finite input alphabet. It is often higher than the capacity for comparable orthogonal pulse systems; sometimes it is superior to all forms of orthogonal signaling with the same PSD.
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| 4. |
- Rusek, Fredrik, et al.
(författare)
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Minimum Distance Analysis of a Certain Class of 2-D ISI Channels
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 58:2, s. 878-887
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Tidskriftsartikel (refereegranskat)abstract
- We perform a minimum distance analysis of a class of two-dimensional intersymbol interference (ISI) channels applicable to multitrack magnetic recording and orthogonal frequency division multiplex transmission systems. Exact minimum distance for a wide class of ISI responses is derived. The fundamental analytical technique is to transform the channel into an equivalent minimum phase channel. The results improve upon the prior work of Soljanin and Georghiades.
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| 5. |
- Rusek, Fredrik, et al.
(författare)
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Mutual Information of IID Complex Gaussian Signals on Block Rayleigh-Faded Channels
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 58:1, s. 331-340
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Tidskriftsartikel (refereegranskat)abstract
- We present a method to compute, quickly and efficiently, the mutual information achieved by an independent identically distributed (IID) complex Gaussian signal on a block Rayleigh-faded channel without side information at the receiver. The method accommodates both scalar and multiple-input multiple-output (MIMO) settings. Operationally, this mutual information represents the highest spectral efficiency that can be attained using Gaussian codebooks. Examples are provided that illustrate the loss in spectral efficiency caused by fast fading and how that loss is amplified when multiple transmit antennas are used. These examples are further enriched by comparisons with the channel capacity under perfect channel-state information at the receiver, and with the spectral efficiency attained by pilot-based transmission.
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