Title : 
Adaptive Modulation in Decode-and-Forward Cooperative Communications With Limited Source-Relay CSI
         
        
            Author : 
Min-Kuan Chang ; Feng-Tsun Chien
         
        
            Author_Institution : 
Grad. Inst. of Commun. Eng., Nat. Chung Hsing Univ., Taichung, Taiwan
         
        
        
        
        
        
        
        
            Abstract : 
In this letter, we study the problem of adaptive modulation (AM) in cooperative decode-and-forward (DF) relaying systems with limited channel state information (CSI) of the source-relay link. We first develop the signal-to-noise ratio (SNR)-based opportunistic AM and obtain the regions of the source-destination and relay-destination link SNR, by which whether cooperative relaying is needed and what constellation size should be chosen can be determined without requiring the source-relay link CSI. We also propose the probabilistic AM to further enhance the transmission rate. Simulation results demonstrate the effectiveness of the proposed AM criteria.
         
        
            Keywords : 
adaptive modulation; cooperative communication; decode and forward communication; probability; radio links; relay networks (telecommunication); wireless channels; SNR-based opportunistic AM; channel state information; cooperative DF relaying system; decode and forward cooperative communication; probabilistic adaptive modulation; relay destination link SNR; signal-to-noise ratio; source destination link SNR; source-relay link CSI; Binary phase shift keying; Cooperative systems; Probabilistic logic; Relays; Signal to noise ratio; Adaptive modulation; Decode-and-forward protocol; Multi-node cooperative communications; adaptive modulation; decode-and-forward protocol;
         
        
        
            Journal_Title : 
Communications Letters, IEEE
         
        
        
        
        
            DOI : 
10.1109/LCOMM.2014.2366099