HARQ Rate Selection Schemes in a Multihop Relay Network With a Delay Constraint

Kim, Seong Hwan; Lee, Seung Joon; Sung, Dan Keun

doi:10.1109/tvt.2014.2343835

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…However, most of these works have focused on extending idealized error correcting codes (ECC) in known channels with either infinite or single-bit feedback. Some works have proposed more realistic models accounting for system-level constraints [17][18][19], bundling multiple packets in one resource block [8,20] and imperfect channel information [21]. The first part of this paper takes one step further in this direction by introducing a new type of IR bits and proposing frameworks to optimize the number and type of IR bits to be sent in scenarios with imperfect ECC, limited feedback, packet bundling, and overhead costs for each round of incremental redundancy.…”

Section: Introductionmentioning

confidence: 99%

Optimizing HARQ and Relay Strategies in Limited Feedback Communication Systems

2020

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One of the key challenges for future communication systems is to deal with fast changing channels due to the mobility of users. Having a robust protocol capable of handling transmission failures in unfavorable channel conditions is crucial, but the feedback capacity may be greatly limited due to strict latency requirements. This paper studies the hybrid automatic repeat request (HARQ) techniques involved in re-transmissions when decoding failures occur at the receiver and proposes a scheme that relies on codeword bundling and adaptive incremental redundancy (IR) to maximize the overall throughput in a limited feedback system. In addition to the traditional codeword extension IR bits, this paper introduces a new type of IR, bundle parity bits, obtained from an erasure code across all the codewords in a bundle. The type and number of IR bits to be sent as a response to a decoding failure is optimized through a Markov Decision Process. In addition to the single link analysis, the paper studies how the same techniques generalize to relay and multi-user broadcast systems. Simulation results show that the proposed schemes can provide a significant increase in throughput over traditional HARQ techniques.

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Section: Introductionmentioning

confidence: 99%

Optimizing HARQ and Relay Strategies in Limited Feedback Communication Systems

2020

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“…In addition, early investigations in [3] proposed a power adaptation scheme for multihop networks under the end‐to‐end BER requirements. Kim et al [4] provide rate selection schemes to maximise the throughput for multihop chase‐combining‐based HARQ (CC‐HARQ) relay network with a delay constraint. The joint optimisation of transmission power and rate for multihop relay networks adopting different HARQ schemes and its comparison are still an interesting and open issue.…”

Section: Introductionmentioning

confidence: 99%

Spectral efficient optimisation for multihop relay networks adopting HARQ schemes

2017

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A joint power and rate optimisation for multihop relay networks adopting different hybrid automatic repeat request (HARQ) schemes are investigated. Specifically, Type-I HARQ, chase-combining-based HARQ and schemes without HARQ are considered with practical system parameters. The optimisation problem is to adjust transmission power and rate of each node to maximise spectral efficiency under the limitations of total power consumption. However, this problem is not always mathematically tractable for three HARQ schemes. Hence, low-complexity iterative algorithms are proposed to obtain the optimisation strategies. Numerical results demonstrate that joint optimisation strategy outperforms conventional separate optimisation strategies significantly. The impact of the path loss conditions is also investigated. It is found that performance improvement increases with increase in link unbalance.

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“…For instance, [4] proposed a joint power and rate optimization scheme to maximize the long-term average transmission rate of the multihop HARQ relay networks under Rayleigh-fading channels. Likewise, the e2e outage probability was studied in [5] by using a Markov chain model.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Resource Allocation in Multihop HARQ Relay Networks with a Delay Constraint

et al. 2017

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Abstract. By minimizing the outage probability, optimization is carried out in this paper to find joint optimal power allocation (OPA) and relay placement (ORP) for multihop relay networks adopting Hybrid Automatic Repeat reQuest (HARQ). Different from previous works, the joint OPA and ORP is analysed under generalized fading channels with the constraint on total transmit power, end-to-end relaying distance and maximum transmission number (delay). The simulation results demonstrate that for different fixed number of nodes and fading models, there are preferred deployments depending on path loss exponent and power retransmission strategy. By employing multiple retransmission round which can improve the reliability and energy efficiency without significant overhead, the end-to-end outage probability is no longer bounded by that of the weaker hop, i.e., the hop with a poor channel condition. The proposed strategy provides a dramatic improvement for the end-to-end outage probability by compensating the channel difference.

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HARQ Rate Selection Schemes in a Multihop Relay Network With a Delay Constraint

Cited by 5 publications

References 28 publications

Optimizing HARQ and Relay Strategies in Limited Feedback Communication Systems

Optimizing HARQ and Relay Strategies in Limited Feedback Communication Systems

Spectral efficient optimisation for multihop relay networks adopting HARQ schemes

Optimization of Resource Allocation in Multihop HARQ Relay Networks with a Delay Constraint

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