DocumentCode :
3253684
Title :
Achievable Rates of Compress-and-Forward Cooperative Relaying on Gaussian Vector Channels
Author :
Simoens, S. ; Munoz, Olga ; Vidal, Julien
Author_Institution :
Motorola Labs, Paris
fYear :
2007
fDate :
24-28 June 2007
Firstpage :
4225
Lastpage :
4231
Abstract :
The compress-and-forward (C&F) cooperative relaying strategy is known to outperform decode-and-forward (D&F) when the relay is close to the destination. In this paper, we derive achievable rates on Gaussian vector channels with cooperative C&F relaying. In order to extend previous information-theoretic results from the scalar to the vector Gaussian channel, we exploit recent results in distributed source coding. Like in source coding with side information at the decoder, the relay applies a conditional Karhunen Loeve transform (CKLT) to its observed signal, followed by a separate Wyner-Ziv encoding of each output stream with a different rate and under a sum-rate constraint. However, these Wyner-Ziv coding rates are such that the total mutual information between the source and destination is maximized. This differs from the conventional source coding approach in which the rates are selected to minimize the total squared distortion, leading to the well-known reverse-waterfilling algorithm. We show that the maximization of the C&F mutual information is also a convex problem. The optimum Wyner-Ziv coding rates have a simple analytical expression, and can be obtained by a waterfilling algorithm. Finally, we illustrate these results by simulations of MIMO-OFDM relaying in a system similar to IEEE802.16.
Keywords :
Gaussian channels; Karhunen-Loeve transforms; MIMO communication; OFDM modulation; combined source-channel coding; decoding; Gaussian vector channels; MIMO-OFDM; Wyner-Ziv encoding; compress-and-forward cooperative relaying; conditional Karhunen Loeve transform; decode-and-forward relay; distributed source coding; reverse-waterfilling algorithm; total squared distortion; Decoding; Gaussian noise; Mutual information; Physical layer; Power system relaying; Relays; Signal processing; Source coding; Time sharing computer systems; Vectors;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Communications, 2007. ICC '07. IEEE International Conference on
Conference_Location :
Glasgow
Print_ISBN :
1-4244-0353-7
Type :
conf
DOI :
10.1109/ICC.2007.697
Filename :
4289368
Link To Document :
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