Differential Distributed Space-Time Coding With Imperfect Synchronization in Frequency-Selective Channels

Avendi, M. R.; Jafarkhani, Hamid

doi:10.1109/twc.2014.2373372

Cited by 25 publications

(25 citation statements)

References 41 publications

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“… extends the scheme in to dual‐relay TWR systems. Similar results are reported in for the conventional one‐way relay channel. However, the schemes in are closer to the traditional differential modulation in the sense that the self‐interference term, that exist for the case of TWR systems, is absent.…”

Section: Introductionsupporting

confidence: 87%

“…Similar results are reported in for the conventional one‐way relay channel. However, the schemes in are closer to the traditional differential modulation in the sense that the self‐interference term, that exist for the case of TWR systems, is absent. For TWR systems, this term consists of N R faded (and possibly misaligned) copies of the considered user's signal, and as the fading coefficients are unknown, the schemes in estimate this term to be able to detect the partner's message.…”

Section: Introductionsupporting

confidence: 87%

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Differential modulation for asynchronous two‐way relay systems over frequency‐selective fading channels

Salim

Duman

2016

Wireless Communications

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In this paper, we propose two schemes for asynchronous multi-relay two-way relay (MR-TWR) systems in which neither the users nor the relays know the channel state information (CSI). In an MR-TWR system, two users exchange their messages with the help of N R relays. Most of the existing works on MR-TWR systems based on differential modulation assume perfect symbol-level synchronization between all communicating nodes. However, this assumption is not valid in many practical systems, which makes the design of differentially modulated schemes more challenging. Therefore, we design differential modulation schemes that can tolerate timing misalignment under frequency-selective fading. We investigate the performance of the proposed schemes in terms of either probability of bit error or pairwise error probability. Through numerical examples, we show that the proposed schemes outperform existing competing solutions in the literature, especially for high signal-to-noise ratio (SNR) values.

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Section: Introductionsupporting

confidence: 87%

Section: Introductionsupporting

confidence: 87%

Differential modulation for asynchronous two‐way relay systems over frequency‐selective fading channels

Salim

Duman

2016

Wireless Communications

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“…where the effective channels f k i (for i ¼ 1; 2; 3; 4) are specifically defined in (5), and the effective noise n k 1 is specified as n…”

Section: Transmission Procedures With Protocol IIImentioning

confidence: 99%

“…In particular, the advantages of MIMO systems, such as capacity and diversity improvements are compared with singleinput single-output (SISO) system adopting the combination of the differential modulation and an orthogonal space time block code (STBC) [3][4][5]. Unfortunately, however, employing a large number of antennas has been considered as an impractical direction for small mobile terminals due to its limited physical hardware size.…”

Section: Introductionmentioning

confidence: 99%

Distributed Differential Quasi-Orthogonal Space-Time Block Coded System for Multiple-Relay Networks

Han

Jeon³

et al. 2015

Wireless Pers Commun

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In this paper, we present an efficient distributed differential quasi-orthogonal space-time block code (DD-QOSTBC) system for multiple relay networks. First, we propose the DD-QOSTBC transmission which considers two robust STBC-like subsystems in amplify-and-forward multiple relaying over flat fading channel. It is assumed that source has two antennas, and relays and destination have a single antenna. With robust STBC-like subsystem structure, we show that our robust subsystems can be used for an efficient joint suboptimal differential decoding based on a maximum likelihood criterion. Finally, we accomplish the performance evaluation on the proposed DD-QOSTBC system in terms of bit-error-rate.

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“…Also, adding intentional timing mismatch was proposed in [12] to improve the performance of a relay network. The authors of [13,14] further proposed several differential decoding schemes for asynchronous multiuser MIMO systems based on orthogonal space-time block codes (OSTBCs) and for differential distributed space-time coding systems with imperfect synchronization.…”

Section: Introductionmentioning

confidence: 99%

An Analysis of Two-User Uplink Asynchronous Non-orthogonal Multiple Access Systems

Zou

Jafarkhani

2019

IEEE Trans. Wireless Commun.

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Recent studies have numerically demonstrated the possible advantages of the asynchronous nonorthogonal multiple access (ANOMA) over the conventional synchronous non-orthogonal multiple access (NOMA). The ANOMA makes use of the oversampling technique by intentionally introducing a timing mismatch between symbols of different users. Focusing on a two-user uplink system, for the first time, we analytically prove that the ANOMA with a sufficiently large frame length can always outperform the NOMA in terms of the sum throughput. To this end, we derive the expression for the sum throughput of the ANOMA as a function of signal-to-noise ratio (SNR), frame length, and normalized timing mismatch. Based on the derived expression, we find that users should transmit at full powers to maximize the sum throughput. In addition, we obtain the optimal timing mismatch as the frame length goes to infinity. Moreover, we comprehensively study the impact of timing error on the ANOMA throughput performance. Two types of timing error, i.e., the synchronization timing error and the coordination timing error, are considered. We derive the throughput loss incurred by both types of timing error and find that the synchronization timing error has a greater impact on the throughput performance compared to the coordination timing error. Index TermsNon-orthogonal multiple access, asynchronous transmission, oversampling, timing mismatch, interference cancellation.Results in this paper were presented in part at d 2N − r 2 d 2N −2 = r 1 (d 2N −2 − r 2 d 2N −4 ),

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Differential Distributed Space-Time Coding With Imperfect Synchronization in Frequency-Selective Channels

Cited by 25 publications

References 41 publications

Differential modulation for asynchronous two‐way relay systems over frequency‐selective fading channels

Differential modulation for asynchronous two‐way relay systems over frequency‐selective fading channels

Distributed Differential Quasi-Orthogonal Space-Time Block Coded System for Multiple-Relay Networks

An Analysis of Two-User Uplink Asynchronous Non-orthogonal Multiple Access Systems

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