Opportunistic Communications with Distorted CSIT

Nam, Young-Han; Zhang, Jianzhong; El-Gamal, Hesham; Reid, T.

doi:10.1109/iswcs.2006.4362250

Cited by 7 publications

(10 citation statements)

References 7 publications

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“…In particular, Lemma 2 demonstrates that the maximum diversity gain can be achieved only when threshold α satisfies α . = P −1 , i.e., the optimal threshold (denoted 23 as α * ) decreases with P when P is large. Similarly, we can intuitively explain why the optimal threshold increases with the number of users K. Specifically, a small threshold α may result in a user k with feedback "1" having a poor channel, and thus, user k with a poor channel may be mistakenly allocated with a large order index since the base station cannot distinguish the channel gains with feedback "1" as discussed in Section II-A.…”

Section: Number Of Users K Common Outage Probabilitymentioning

confidence: 99%

“…One of the most spectrally efficient approaches is to employ one-bit feedback for opportunistic user selection, which was proposed for the fading BC in [21]- [26]. The outage performance with one-bit feedback was investigated in [23], [25], and the use of one-bit feedback has also been applied to the MIMO case in [27], [28]. This paper investigates the block fading BC with one bit feedback from the new perspective of NOMA.…”

Section: Introductionmentioning

confidence: 99%

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On the Outage Performance of Non-Orthogonal Multiple Access With 1-bit Feedback

Yuan

Ding

et al. 2016

IEEE Trans. Wireless Commun.

113

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In this paper, the outage performance of downlink non-orthogonal multiple access (NOMA) is investigated for the case where each user feeds back only one bit of its channel state information (CSI) to the base station. Conventionally, opportunistic one-bit feedback has been used in fading broadcast channels to select only one user for transmission. In contrast, the considered NOMA scheme adopts superposition coding to serve all users simultaneously in order to improve user fairness. A closed-form expression for the common outage probability (COP) is derived, along with the optimal diversity gains under two types of power constraints. Particularly, it is demonstrated that the diversity gain under a long-term power constraint is twice as large as that under a short-term power constraint. Furthermore, we study dynamic power allocation optimization for minimizing the COP, based on one-bit CSI feedback.This problem is challenging since the objective function is non-convex; however, under the short-term power constraint, we demonstrate that the original problem can be transformed into a set of convex problems. Under the long-term power constraint, an asymptotically optimal solution is obtained for high signal-to-noise ratio. Index TermsNon-orthogonal multiple access, downlink transmission, common outage probability, one-bit feedback, power allocation.

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Section: Number Of Users K Common Outage Probabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Outage Performance of Non-Orthogonal Multiple Access With 1-bit Feedback

Yuan

Ding

et al. 2016

IEEE Trans. Wireless Commun.

113

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“…We evaluate the outage probability and DMT of the proposed 1-bit feedback scheme. In contrast with [10] and [22], where the results are developed based on a short-term average power constraint, in this paper, we analyze the 1-bit feedback scheme with long-term average power constraint, for both cases of instantaneous feedback and outdated feedback. The analysis follows [26]- [28] that focused on the DMT with long-term power constraint for single-user MIMO systems.…”

Section: Main Contributions and Relation To Previous Workmentioning

confidence: 99%

“…In these works, it has been proved that the 1-bit feedback scheme preserves the optimal scaling law of log log K (see also [21] for an extension to the MIMO case), i.e., it preserves the scaling law of multiuser diversity with full CSI feedback. For the outage case, the outage performance and DMT for the opportunistic scheme with 1-bit feedback in a K-user channel are studied in [22]. It is found that with a fixed transmission rate, the optimal DMT is d(r) = K(1 − r) + , which is the same as if full CSI were available at the transmitter.…”

mentioning

confidence: 99%

“…A closedform expression for the sum-rate as a function of the fading temporal correlation ρ is derived therein. With regard to the outage performance case, it is proved in [22] that opportunistic schemes, with short-term power constraints (i.e., a varying power allocation is not allowed), can not achieve an improved DMT in the presence of delayed CSI feedback.…”

mentioning

confidence: 99%

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Ergodic and Outage Performance of Fading Broadcast Channels with 1-Bit Feedback

Niu¹,

Simeone²,

Somekh³

et al. 2010

Preprint

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In this paper, the ergodic sum-rate and outage probability of a downlink single-antenna channel with K users are analyzed in the presence of Rayleigh flat fading, where limited channel state information (CSI) feedback is assumed. Specifically, only 1-bit feedback per fading block per user is available at the base station. We first study the ergodic sumrate of the 1-bit feedback scheme, and consider the impact of feedback delay on the system. A closed-form expression for the achievable ergodic sum-rate is presented as a function of the fading temporal correlation coefficient. It is proved that the sumrate scales as log log K, which is the same scaling law achieved by the optimal non-delayed full CSI feedback scheme. The sumrate degradation due to outdated CSI is also evaluated in the asymptotic regimes of either large K or low SNR. The outage performance of the 1-bit feedback scheme for both instantaneous and outdated feedback is then investigated. Expressions for the outage probabilities are derived, along with the corresponding diversity-multiplexing tradeoffs (DMT). It is shown that with instantaneous feedback, a power allocation based on the feedback bits enables to double the DMT compared to the case with shortterm power constraint in which a dynamic power allocation is not allowed. But, with outdated feedback, the advantage of power allocation is lost, and the DMT reverts to that achievable with no CSI feedback. Nevertheless, for finite SNR, improvement in terms of outage probability can still be obtained.

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A Simple Reservation Scheme for Multicarrier Channel Aware Aloha

Ganesan

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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Opportunistic Communications with Distorted CSIT

Cited by 7 publications

References 7 publications

On the Outage Performance of Non-Orthogonal Multiple Access With 1-bit Feedback

On the Outage Performance of Non-Orthogonal Multiple Access With 1-bit Feedback

Ergodic and Outage Performance of Fading Broadcast Channels with 1-Bit Feedback

A Simple Reservation Scheme for Multicarrier Channel Aware Aloha

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