The Ergodic Capacity of the Multiple Access Channel Under Distributed Scheduling - Order Optimality of Linear Receivers

Kampeas, Joseph; Cohen, Asaf; Gurewitz, Omer

doi:10.1109/tit.2018.2807484

Cited by 11 publications

(7 citation statements)

References 52 publications

(67 reference statements)

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“…Note that w b has to be orthogonal to h w and h c ; and w c,1 has to have non-zero projections on h w and h c , which means it has to be orthogonal to h b . Since the probability that h b falls in the space spanned by h w and h c is zero, the number of antennas at Alice is no less than three [41], [42].…”

Section: B Proposed Zero-forcing Beamformers Designmentioning

confidence: 99%

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Robust Beamforming Design for Covert Communications

Al-Dhahir³

et al. 2021

Preprint

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In this paper, we consider a common unicast beamforming network where Alice utilizes the communication to Carol as a cover and covertly transmits a message to Bob without being recognized by Willie. We investigate the beamformer design of Alice to maximize the covert rate to Bob when Alice has either perfect or imperfect knowledge about Willie's channel state information (WCSI). For the perfect WCSI case, the problem is formulated under the perfect covert constraint, and we develop a covert beamformer by applying semidefinite relaxation and the bisection method. Then, to reduce the computational complexity, we further propose a zero-forcing beamformer design with a single iteration processing. For the case of the imperfect WCSI, the robust beamformer is developed based on a relaxation and restriction approach by utilizing the property of Kullback-Leibler divergence. Furthermore, we derive the optimal decision threshold of Willie, and analyze the false alarm and the missed detection probabilities in this case. Finally, the performance of the proposed beamformer designs is evaluated through numerical experiments.

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Section: B Proposed Zero-forcing Beamformers Designmentioning

confidence: 99%

“…Furthermore, we analyze the multiplexing gains of the covert communication system based on ZF beamformer design [42]. Specifically, based on the definitions…”

Section: B Proposed Zero-forcing Beamformers Designmentioning

confidence: 99%

Robust Beamforming Design for Covert Communications

Al-Dhahir³

et al. 2021

Preprint

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“…This ratio is distributed as the minimum of L 2 − 1 i.i.d. uniform [0, 1] random variables [32, Lemma 3.2], [33]. This is since the ratio can be interpreted as the proportion of the waiting time from the first arrival to the L 2 arrival of a Poisson process.…”

Section: A Minimization Of the Quadratic Form Fmentioning

confidence: 99%

Compute-and-Forward in Large Relaying Systems: Limitations and Asymptotically Optimal Scheduling

Shmuel¹,

Cohen²,

Gurewitz³

2020

Preprint

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Compute and Forward (CF) is a coding scheme which enables receivers to decode linear combinations of simultaneously transmitted messages while exploiting the linear properties of lattice codes and the additive nature of a shared medium. The scheme was originally designed for relay networks, yet, it was found useful in other communication problems, such as MIMO communication. Works in the current literature assume a fixed number of transmitters and receivers in the system. However, following the increase in communication networks density, it is interesting to investigate the performance of CF when the number of transmitters is large.In this work, we show that as the number of transmitters grows, CF becomes degenerated, in the sense that a relay prefers to decode only one (strongest) user instead of any other linear combination of the transmitted codewords, treating the other users as noise. Moreover, the system's sum-rate tends to zero as well. This makes scheduling necessary in order to maintain the superior abilities CF provides.We thus examine the problem of scheduling for CF. We start with insights on why good scheduling opportunities can be found. Then, we provide an asymptotically optimal, polynomial-time scheduling algorithm and analyze its performance. We conclude that with proper scheduling, CF is not merely non-degenerated, but, in fact, provides a gain for the system sum-rate, up to the optimal scaling law of O(log log L).

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“…However, for i.i.d. Chisquare random variables, the convergence of its maximum to the Gumbel distribution with parameters c K and d K is quite slow [45]. Specially, for a large M , Γ(M ) is an excessively large number, i.e., Γ(20) = 1.2165 × 10 17 , thus d K may not be positive for a moderate value of K. Therefore, we calculate new normalizing constants of Ξ K (1) by approximating Chi-square random variables as Gaussian ones.…”

Section: B Low Snr Regimementioning

confidence: 99%

Secure Communication in Uplink Transmissions: User Selection and Multiuser Secrecy Gain

Deng

Wang

Yuan

et al. 2016

IEEE Trans. Commun.

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Abstract-In this paper, we investigate secure communications in uplink transmissions, where there are a base station (BS) with M receive antennas, K mobile users each with a single antenna, and an eavesdropper with N receive antennas. The closed-form expressions of the achievable ergodic secrecy sumrates (ESSR) for a random k users selection scheme in the high and low SNR regimes are presented. It is shown that the scaling behavior of ESSR with respect to the number of served users k can be quite different under different system configurations, determined by the numbers of the BS antennas and that of the eavesdropper antennas. In order to achieve a multiuser gain, two low-complexity user selection schemes are proposed under different assumptions on the eavesdropper's channel state information (CSI). The closed-form expressions of the achievable ESSRs and the multiuser secrecy gains of the two schemes are also presented in both low and high SNR regimes. We observe that, as k increases, the multiuser secrecy gain increases, while the ESSR may decrease. Therefore, when N is much larger than M , serving one user with the strongest channel (TDMA-like) is a favourable secrecy scheme, where the ESSR scales with √ 2 log K.Index Terms-Physical layer security, ergodic secrecy rate, user selection, multiuser secrecy gain, extreme value theory.

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The Ergodic Capacity of the Multiple Access Channel Under Distributed Scheduling - Order Optimality of Linear Receivers

Cited by 11 publications

References 52 publications

Robust Beamforming Design for Covert Communications

Robust Beamforming Design for Covert Communications

Compute-and-Forward in Large Relaying Systems: Limitations and Asymptotically Optimal Scheduling

Secure Communication in Uplink Transmissions: User Selection and Multiuser Secrecy Gain

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