Buffer-aided cooperative communications: opportunities and challenges

Zlatanov, Nikola; Ikhlef, Aïssa; Islam, Tazul; Schober, Robert

doi:10.1109/mcom.2014.6807959

Cited by 184 publications

(139 citation statements)

References 12 publications

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“…Such adaptive relaying efficiently schedules the S-R link and R-D link depending on their channel conditions in each frame. As a result, adaptive relaying can attain significant throughput gains over fixed relaying since it can exploit the link diversity by transmitting over the link with more favorable channel condition [45]- [47]. One disadvantage of buffer-aided adaptive relaying is that it introduces random queuing delay at the relay, which is not present under non-buffer relaying.…”

Section: Half-duplex Relaying With Adaptive Link Selectionmentioning

confidence: 99%

“…Recently, the works [43], [44] introduce the idea of buffer-aided relaying, where the relay employs buffer to store the received data from the source for future transmission to the destination. Thanks to the buffer-aided relaying capability, adaptive link selection relaying is possible, where either the source-relay link or the relay-destination link is active depending on the channel state information (CSI) in each transmission frame [45]- [47]. While adaptive relaying is able to exploit the link fading diversity, one disadvantage is the (queueing) delay incurred at the relay buffer, which is assumed to be unconstrained or under average delay constraint in existing works [43]- [47].…”

Section: Introductionmentioning

confidence: 99%

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Radio Resource Allocation Over Fading Channels Under Statistical Delay Constraints

Phan¹,

Le‐Ngoc²

2017

SpringerBriefs in Electrical and Computer Engineering

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Wireless data transmission suffers from the fading nature of wireless channels, where the instantaneous channel conditions and hence transmission rates randomly fluctuate over time. Consequently, data arrivals at each transmitter might not be transmitted instantly. To cope with this situation, the transmitter employs buffer to store the data temporarily for later transmission. While data buffering enables more efficient radio resource allocation to opportunistically select the favorable fading conditions for transmission, it introduces queuing delay that needs to be controlled in order to meet the end-to-end delay quality-ofservice (QoS) requirements in supporting delay-sensitive communications. In this thesis, we study and develop radio resource allocation schemes for buffer-aided communications over wireless fading channels under statistical delay constraints. Using the buffering capability as a means to exploit the fading diversity, the nodes (source and relay) perform resource allocation, and adapt their transmissions to the channel state information (CSI) in order to enhance the system throughput while maintaining the statistical delay QoS requirements in terms of upper-bounded average delay or delay-outage probability.The thesis starts by considering a source-destination communications link over a fading channel with data arriving at the source transmission buffer. In the first scenario, the source is assumed to have a maximum power constraint and an average delay constraint. We consider admission control applied on random data arrivals to the source buffer in order to avoid constraint violation, and study the joint optimal data admission control and power allocation (AC-PA) problem for throughput maximization. In the second scenario, we consider an energy-harvesting (EH) source, where random amounts of energy are harvested from renewable energy sources, and stored in a battery during the course of data transmission. In every transmission time slot, the source is constrained to use at most the amount of energy currently stored. We then explore optimal power allocation problems for such EH systems under average delay or delay-outage constraints. We formulate the problems as infinite horizon constrained Markov decision process (MDP) problems, which incorporate the random variations of the fading channel, data arrival, and EH processes. A novel solution approach based on post-decision state-value function is proposed to study the properties of the optimal solutions. We also propose online allocation algorithms when the statistical knowledge of the random processes is unknown, which is typical in real-life communications. Illustrative results demonstrate the effectiveness of the proposed algorithms over existing approaches iii under similar power and delay constraints.The thesis continues with a source-relay-destination communications link over fading channels with buffers available at both source and relay, as part of a multi-hop network. We investigate and develop optimal resource allocation schemes ...

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Section: Half-duplex Relaying With Adaptive Link Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radio Resource Allocation Over Fading Channels Under Statistical Delay Constraints

Phan¹,

Le‐Ngoc²

2017

SpringerBriefs in Electrical and Computer Engineering

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“…Cooperative comunication has recently attracted method to improve the performace [1][2][3][4][5][6][7]. In multi-hop cooperative communications, the source transmits signal to relays that forward signal to the destination or other relays.…”

Section: Introductionmentioning

confidence: 99%

The Optimal Power Allocation with Hybrid Relaying Based on Channel Condition

Jeon¹,

Shim²,

Park³

2018

Preprint

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This paper considers a hybrid relay network consisting of the source, the amplify-and-forward (AF) relay, the decode-and-forward (DF) relay, and the destination. We propose the optimal power allocation schemes between two different relays which maximize the achievable rate under a sum relay power constraint for given channel gains and transmit power from source. By solving the optimization problem to maximize the achievable rate for each relay network, the 5 transmit power values in closed-form are derived. When the channel gains are the same, the optimal power allocation scheme for AF-DF relay network proves that a more power should be allocated at the first relay to maximize the achievable rate. In case of the DF-AF relay network, we derive the optimal power allocation scheme for the possible four cases. Under the same SNR condition at the first hop, we show that the achievable rate of AF-DF relay network is greater than that of DF-AF relay 10 network when the channel gain between two relays is higher than that between the second relay and destination. Simulation results show that the proposed power allocation schemes provide a higher achievable rate than the equal power allocation schemes.

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“…The literature [16] focused on the multi-antenna relaying system with buffer at relay and pointed out that if the numbers of antennas at source and destination are equal or larger than the number of antennas at relay, the buffer-aided half-duplex systems can outperform the ideal full-duplex ones. Motivated by the works [14] and [15], the buffer-aided relay systems have been investigated widely such as in [17][18][19][20][21][22][23][24][25]. Later, in [26] and [27] the idea of buffer-aided relaying was expanded to multiple relay systems, where the authors have proposed the max-max link selection (MMLS) protocol firstly.…”

Section: Introductionmentioning

confidence: 99%

Diversity and delay performance of max link selection relay cooperation systems over non-identical Nakagami-m fading channels

Jia

Zhou

Dang

et al. 2016

J Wireless Com Network

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The work focuses on the max link selection (MLS) schemes of buffer-aided relaying over the independent and non-identically distributed (i.ni.d) Nakagami-m fading channels in terms of outage probability, average packet delay, and improved diversity-delay trade-off schemes. By modeling the transition of buffer states as a Markov chain, we first obtain the outage probability and average packet delays for MLS schemes, which are given with closed-form expressions. The achieved results show that the i.ni.d fading channels impose severe loss in the diversity and coding gains of MLS schemes. Especially, when the disparity among the channel powers is very large, the diversity order provided by the MLS schemes is less than the ones provided by the traditional best relay selection (T-BRS) and max-max link selection (MMLS) schemes even if the buffers' size is large enough. For the average packet delay of MLS schemes, our results show that they are impacted by the transmit power and the fading severity factors. In general, in the low transmit power, the average packet delays are varying with the transmit power. However, in the high transmit power, the average packet delays approach the stationary values. Besides of this, it is also achieved that the i.ni.d fading makes the average packet delays of MLS schemes at all relays are different. When the powers of relay-destination links are greater than the ones of source-relay links, the average packet delays can be reduced evidently. Motivated by the observations, a weight-based MLS (W-MLS) diversity-delay trade-off scheme is proposed. The proposed W-MLS diversity-delay trade-off schemes not only have the low packet delays at all relays but also provide enough diversity and coding gains over T-BRS and MMML, which can overcome the performance loss caused by non-identical distribution on MLS schemes.

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Buffer-aided cooperative communications: opportunities and challenges

Cited by 184 publications

References 12 publications

Radio Resource Allocation Over Fading Channels Under Statistical Delay Constraints

Radio Resource Allocation Over Fading Channels Under Statistical Delay Constraints

The Optimal Power Allocation with Hybrid Relaying Based on Channel Condition

Diversity and delay performance of max link selection relay cooperation systems over non-identical Nakagami-m fading channels

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