This paper proposes a simple estimate-and-forward (EF) scheme for two-way relay networks.The relay node firstly calculates log-likelihood ratio (LLR) of bits from source nodes

then physical network encoding is performed in LLR domain instead of binary bits.The resulting new LLR is employed to generate the transmitted symbols at relay.Both upper and lower bounds are derived on the achievable sum rate of the proposed EF scheme.Performance evaluations confirm that EF scheme can improve the achievable sum rate and the bit error rate compared to conventional amplify-and-forward (AF) and decode-and-forward (DF) schemes.