Title :
Autoregressive Time-Varying Flat-Fading Channels: Model Order and Information Rate Bounds
Author :
Sadeghi, Parastoo ; Rapajic, Predrag ; Kennedy, Rodney ; Abhayapala, Thushara
Author_Institution :
Australian Nat. Univ., Canberra, ACT
Abstract :
In this paper, we study the effect of channel memory order on the information rate bounds in time-varying flat-fading (FF) channels. We model time variations of the FF channel with autoregressive (AR) processes with varying degrees of model order. We observe that in high SNR conditions (SNR 20 dB), the information rate penalty of not knowing the AR channel is a non-increasing function of the AR model order. This is expected, since the AR channel predictability cannot decrease with increasing its order. However, in low SNR conditions, the information rate penalty in low-order AR channels can be lower than those in high-order AR channels. Likewise, the intuitive and universal monotonic increase of the information rate bounds with the AR model order is only observed in almost noiseless conditions. In the low SNR regime, however, the achievable information rate bounds in low-order AR channels can be higher than those in high-order AR channels
Keywords :
autoregressive processes; fading channels; SNR; autoregressive time-varying flat-fading channels; channel predictability; information rate bounds; Australia; Channel state information; Fading; Information rates; Mobile communication; Predictive models; Random processes; Time varying systems; Time-varying channels; Transmitters;
Conference_Titel :
Information Theory, 2006 IEEE International Symposium on
Conference_Location :
Seattle, WA
Print_ISBN :
1-4244-0505-X
Electronic_ISBN :
1-4244-0504-1
DOI :
10.1109/ISIT.2006.261890