| 1. |
- Durisi, Giuseppe, 1977, et al.
(författare)
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Short-packet transmission
- 2021
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Ingår i: Information Theoretic Perspectives on 5G Systems and Beyond. - 9781108416474
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- 5G, a new generation of cellular technology under deployment worldwide, can provide about 100 times faster communications than current 4G technology. But a higher speed is not the sole differentiating factor: 5G is also more reliable, secure, and capable of ubiquitously connecting a massively large number of devices. Ultra-reliable, low-delay, omni-present 5G networks hold the promise of enabling a range of new applications, including self-driving cars, highly automatized industrial tasks, virtual reality gaming, as well as of providing the connectivity platform for the Internet of Things (IoT). Since its introduction in 1948, information theory has underpinned the mathematical foundations of communication systems, including 5G networks, and it will impact the design of cellular systems beyond 5G. The theoretical insights obtained by information theory point to the optimal system performance under a given model, offering strong guidelines and benchmarks for the design and validation of modern communication technologies. Information Theoretic Perspectives on 5G Systems and Beyond provides a comprehensive overview of the state-of-art information-theoretic approaches that led to realization of 5G. Three main areas are discussed, namely network architecture, coding and modulation, and network protocols. Examples of covered topics include cloud/fog radio access networks (a central component in future 6G (beyond 5G) cell-less structure), device-to-device communications, caching, energy harvesting, polar coding, Massive MIMO, short-packet transmission, NOMA, 5G protocols, interference management, content delivery, and cooperative and confidential communications. Information Theoretic Perspectives on 5G Systems and Beyond is the result of a grand effort by more than 40 experts in the field of information theory. It includes 19 chapters, offering a detailed introduction to advanced topics in information theory, and it took several years in making. We are extremely excited that the book is now available. We hope that it can serve as a tool for researchers and graduate students in the fields of information theory and wireless communications, as well as for practitioners in the telecommunications industry.
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| 2. |
- Dörpinghaus, Meik, 1977, et al.
(författare)
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Oversampling increases the pre-log of noncoherent Rayleigh fading channels
- 2014
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 60:9, s. 5673-5681
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the capacity of a continuous-time, time- selective, Rayleigh block-fading channel in the high signal-to-noise ratio regime. The fading process is assumed stationary within each block and to change independently from block to block; further- more, its realizations are not known a priori to the transmitter and the receiver (noncoherent setting). A common approach to analyzing the capacity of this channel is to assume that the receiver performs matched filtering followed by sampling at symbol rate (symbol matched filtering). This yields a discrete-time channel in which each transmitted symbol corresponds to one output sample. Liang & Veeravalli (2004) showed that the capacity of this discrete- time channel grows logarithmically with the signal-to noise ratio (SNR), with a capacity pre-log equal to 1 − Q/N . Here, N is the number of symbols transmitted within one fading block, and Q is the rank of the covariance matrix of the discrete-time channel gains within each fading block. In this paper, we show that sym- bol matched filtering is not a capacity-achieving strategy for the underlying continuous-time channel. Specifically, we analyze the capacity pre-log of the discrete-time channel obtained by oversam- pling the continuous-time channel output, i.e., by sampling it faster than at symbol rate. We prove that by oversampling by a factor two one gets a capacity pre-log that is at least as large as 1 − 1/N . Since the capacity pre-log corresponding to symbol-rate sampling is 1−Q/N , our result implies indeed that symbol matched filtering is not capacity achieving at high SNR.
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| 3. |
- Rezazadeh, Arezou, 1987, et al.
(författare)
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Conditional Mutual Information-Based Generalization Bound for Meta Learning
- 2021
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Ingår i: IEEE International Symposium on Information Theory - Proceedings. - 2157-8095. ; 2021-July, s. 1176-1181
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Konferensbidrag (refereegranskat)abstract
- Meta-learning optimizes an inductive bias—typically in the form of the hyperparameters of a base-learning algorithm—by observing data from a finite number of related tasks. This paper presents an information-theoretic bound on the generalization performance of any given meta-learner, which builds on the conditional mutual information (CMI) framework of Steinke and Zakynthinou (2020). In the proposed extension to meta-learning, the CMI bound involves a training meta-supersample obtained by first sampling 2N independent tasks from the task environment, and then drawing 2M independent training samples for each sampled task. The meta-training data fed to the meta-learner is modelled as being obtained by randomly selecting N tasks from the available 2N tasks and M training samples per task from the available 2M training samples per task. The resulting bound is explicit in two CMI terms, which measure the information that the meta-learner output and the base-learner output provide about which training data are selected, given the entire meta-supersample. Finally, we present a numerical example that illustrates the merits of the proposed bound in comparison to prior information-theoretic bounds for meta-learning
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| 4. |
- Yang, Wei, 1987, et al.
(författare)
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Finite-Blocklength Channel Coding Rate Under a Long-Term Power Constraint
- 2014
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Ingår i: IEEE International Symposium on Information Theory - Proceedings. - 2157-8095. - 9781479951864 ; , s. 2067-2071
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the maximal channel coding rate achievable at a given blocklength $n$ and error probability $\epsilon$, when the codewords are subject to a long-term (i.e., averaged-over-all-codeword) power constraint. The second-order term in the large-n expansion of the maximal channel coding rate is characterized both for AWGN channels and for quasi-static fading channels with perfect channel state information at the transmitter and the receiver. It is shown that in both cases the second-order term is proportional to $\sqrt{(\log n)/n}$.
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| 5. |
- Yang, Wei, 1987, et al.
(författare)
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Optimum Power Control at Finite Blocklength
- 2015
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 61:9, s. 4598-4615
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the maximal channel coding rate achievable at a given blocklength $n$ and error probability $\epsilon$, when the codewords are subject to a long-term (i.e., averaged-over-all-codeword) power constraint. The second-order term in the large-$n$ expansion of the maximal channel coding rate is characterized both for additive white Gaussian noise (AWGN) channels and for quasi-static fading channels with perfect channel state information available at both the transmitter and the receiver. It is shown that in both cases the second-order term is proportional to $\sqrt{n^{-1}\ln n}$. For the quasi-static fading case, this second-order term is achieved by \emph{truncated channel inversion}, namely, by concatenating a dispersion-optimal code for an AWGN channel subject to a short-term power constraint, with a power controller that inverts the channel whenever the fading gain is above a certain threshold. Easy-to-evaluate approximations of the maximal channel coding rate are developed for both the AWGN and the quasi-static fading case.
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| 6. |
- Zetterberg, P., et al.
(författare)
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Initial multi-node and antenna transmitter and receiver architectures and schemes; Deliverable D5.1
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable provides the initial concepts and solutions from the technical work related to multi-antenna and multi-node transceiver schemes in millimetre wave (denoted as 6-100GHz) spectrum. It also briefly presents the use cases on which the work will be based and categorises the solutions in terms of their applicability to access, backhaul and relay deployments. Another important contribution from this report is the modelling of the hardware impairments in millimetre wave transceivers and the analysis of their impact on system performance.
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| 7. |
- Aabel, Lise, et al.
(författare)
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A TDD Distributed MIMO Testbed Using a 1-bit Radio-Over-Fiber Fronthaul Architecture
- 2024
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- We present the uplink and downlink of a time-division duplex distributed multiple-input multiple-output (D-MIMO) testbed, based on a 1-bit radio-over-fiber architecture, which is low cost and scalable. The proposed architecture involves a central unit (CU) that is equipped with 1-bit digital-to-analog and analog-to-digital converters, operating at 10 GS/s. The CU is connected to multiple single-antenna remote radio heads (RRHs) via optical fibers, over which a binary radio frequency (RF) waveform is transmitted. In the uplink, a binary RF waveform is generated at the RRHs by a comparator, whose inputs are the received RF signal and a suitably designed dither signal. In the downlink, a binary RF waveform is generated at the CU via bandpass sigma-delta modulation. Our measurement results show that low error-vector magnitude (EVM) can be achieved in both the uplink and the downlink, despite 1-bit sampling at the CU. Specifically, for point-to-point over-cable transmission between a single user equipment (UE) and a CU equipped with a single RRH, we report, for a 10-MBd signal using single-carrier (SC) 16 quadratic-amplitude modulation (QAM) modulation, an EVM of 3.3% in the downlink, and of 4.5% in the uplink. We then consider a CU connected to three RRHs serving over the air two UEs, and show that, after over-the-air reciprocity calibration, a downlink zero-forcing precoder designed on the basis of uplink channel estimates at the CU achieves an EVM of 6.4% and 10.9% at UE 1 and UE 2, respectively. Finally, we investigate the ability of the proposed architecture to support orthogonal frequency-division multiplexing (OFDM) waveforms, and its robustness against both in-band and out-of-band interference.
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| 8. |
- Aabel, Lise, 1992, et al.
(författare)
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Distributed Massive MIMO via all-Digital Radio Over Fiber
- 2020
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Ingår i: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2020-November, s. 319-323
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Konferensbidrag (refereegranskat)abstract
- A crucial challenge in the implementation of distributed massive multiple-input multiple-output (MIMO) architectures is to provide phase coherence while, at the same time, limit the complexity of the remote-radio heads (RRHs), which is important for cost-efficient scalability. To address this challenge, we present in this paper a phase-coherent distributed MIMO architecture, based on off-the-shelf, low-cost components. In the proposed architecture, up- and down-conversion are carried out at the central unit (CU). The RRHs are connected to the CU by means of optical fibers carrying oversampled radio-frequency (RF) 1-bit signals. In the downlink, the 1-bit signal is generated via sigma-delta modulation. At the RRH, the RF signal is recovered from the 1-bit signal through a bandpass filter and a power amplifier, and then fed to an antenna. In the uplink, the 1-bit signal is generated by a comparator whose inputs are the low-noise-amplified received RF signal and a suitably designed dither signal. The performance of the proposed architecture is evaluated with satisfactory results both via simulation and measurements from a testbed.
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| 9. |
- Agrell, Erik, 1965, et al.
(författare)
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Capacity of a nonlinear optical channel with finite memory
- 2014
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 32:16, s. 2862-2876
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Tidskriftsartikel (refereegranskat)abstract
- The channel capacity of a nonlinear, dispersive fiber-optic link is revisited. To this end, the popular Gaussian noise (GN) model is extended with a parameter to account for the finite memory of realistic fiber channels. This finite-memory model is harder to analyze mathematically but, in contrast to previous models, it is valid also for nonstationary or heavy-tailed input signals. For uncoded transmission and standard modulation formats, the new model gives the same results as the regular GN model when the memory of the channel is about ten symbols or more. These results confirm previous results that the GN model is accurate for uncoded transmission. However, when coding is considered, the results obtained using the finite-memory model are very different from those obtained by previous models, even when the channel memory is large. In particular, the peaky behavior of the channel capacity, which has been reported for numerous nonlinear channel models, appears to be an artifact of applying models derived for independent input in a coded (i.e., dependent) scenario. © 1983-2012 IEEE.
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| 10. |
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