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2008

Cross-Layer Rate and Power Adaptation Strategies for IR-HARQ Systems over Fading Channels with Memory: A SMDP-Based Approach

8 years 6 months ago
Cross-Layer Rate and Power Adaptation Strategies for IR-HARQ Systems over Fading Channels with Memory: A SMDP-Based Approach
Abstract--Incremental-redundancy hybrid automatic repeatrequest (IR-HARQ) schemes are proposed in several wireless standards for increased throughput-efficiency and greater reliability. We investigate transmit power and modulation order adaptation strategies for the IR-HARQ schemes over correlated Rayleigh fading channels using semi-Markov decision processbased model. In order to jointly analyze physical layer and link layer, transmitter model incorporates a finite-size buffer that receives randomly varying traffic from a higher layer application. It is assumed that channel variations can be modeled with a firstorder Markov chain. We show that the optimal transmission power and rate adaptation laws under buffering delay and packet overflow constraints can be obtained using the framework of semi-Markov decision process. We discuss three different adaptation models for the IR-HARQ schemes and compare their performances with the non-adaptive scheme. It is shown that unique optimal policy ...
Ashok K. Karmokar, Dejan V. Djonin, Vijay K. Bharg
Added 15 Dec 2010
Updated 15 Dec 2010
Type Journal
Year 2008
Where TCOM
Authors Ashok K. Karmokar, Dejan V. Djonin, Vijay K. Bhargava
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