Generalized HARQ Protocols with Delayed Channel State Information and Average Latency Constraints

Autor: Petar Popovski, Kasper Floe Trillingsgaard
Jazyk: angličtina
Rok vydání: 2018
Předmět:
FOS: Computer and information sciences
Computer science
Retransmission
Delayed channel state information
Computer Science - Information Theory
Hybrid automatic repeat request
Low latency
050801 communication & media studies
Throughput
02 engineering and technology
Data_CODINGANDINFORMATIONTHEORY
Library and Information Sciences
Dynamic programming
0508 media and communications
0202 electrical engineering
electronic engineering
information engineering
Latency (engineering)
business.industry
Backtrack retransmission request
Information Theory (cs.IT)
05 social sciences
Transmitter
ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS
020206 networking & telecommunications
Computer Science Applications
Channel state information
business
Decoding methods
Information Systems
Communication channel
Computer network
Zdroj: IEEE Transactions on Information Theory
Trillingsgaard, K F & Popovski, P 2018, ' Generalized HARQ Protocols with Delayed Channel State Information and Average Latency Constraints ', I E E E Transactions on Information Theory, vol. 64, no. 2, 7814295, pp. 1262-1280 . https://doi.org/10.1109/TIT.2017.2651836
DOI: 10.1109/TIT.2017.2651836
Popis: In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low latency. This paper put forth the family of expandable message space (EMS) protocols that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that the throughput of BRQ approaches the ergodic capacity quickly compared to HARQ, while EMS protocols with only three and four feedback messages achieve throughputs that are only slightly worse than that of BRQ.
19 pages, 5 figures
Databáze: OpenAIRE
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