The compress-and-forward strategy allows the relay node to compress the received signal before transmitting it to the destination node, where the Wyner-Ziv coding has been known as the optimal compression algorithm.

## Reference Phrases Edit

- Sébastien Simoens, Josep Vidal, Olga Muñoz, "COMPRESS-AND-FORWARD COOPERATIVE RELAYING IN MIMO-OFDM SYSTEMS"
- In our evaluation we consider MIMO-OFDM transmission. An achievable rate was previously derived in [6] assuming a scalar channel. We extend this Wyner-Ziv bound to MIMO-OFDM, by applying results from Bayesian vector estimation and rate-distortion coding theory. Then we derive the mutual information of a sub-optimal relaying scheme in which the relay applies Karhunen-Loeve transform to the signal received from the source before quantizing it and forwarding it to the destination as a new codeword.

## Simple Compress and Forward Edit

The simple compress and forward relay network allows the relay node to send its received signal from the source node to the destination node after quantization of the received signal, while the full compress and forward relay network sends with winner-zip encoding additionally.

### System Model Edit

We now consider the final received signal at the destination node after the simple compress-and-forward relay is applied. It is assumed that the relay channel is a AWGN link with the unit variance noise while the channel from the source node to the relay node is Rayleigh link with the $ P $ transmit power signal and the unit variance noise.

The received signal at the relay node and the received signal at the destination node are

- $ r_{r} = h_{s,r}*x_{s} + n_{s,r} $
- $ r_{d} = h_{s,r}*x_{s} + n_{s,r} + n_{eff} $

where $ n_{eff} $ is the effective noise signal from the relay node to the destination node by digital relaying transmission at the relay node.