Patent ID: 8750788

Claim:
A multiple data stream transmission method in a relay system including a relay node, the method comprising: receiving, by the relay node, a plurality of data streams from a source node; decoding, by the relay node, the received plurality of data streams; selecting, by the relay node, a portion of the data streams which have been decoded successfully; encoding, by the relay node, the selected portion of the data streams by using multi-layer superposition coding; and transmitting, by the relay node, the encoded portion of the data streams to a destination node in a collaborative transmission phase, wherein the multi-layer superposition coding is performed according to a number of transmit antennas and an adaptive parameter L, and wherein the adaptive parameter L is set by the following equation A: L = ∑ m = 1 M ⁢ u ⁡ ( γ 1 , m - γ 0 , m ) ( equation ⁢ ⁢ A ) where γ 0,m (m=1, 2, . . . , M) is a per-antenna signal-to-interference-plus-noise ratio (SINR) of a direct link between the source node and the destination node, where γ 1,m (m=1, 2, . . . , M) is a per-antenna SINR of a relay link between the source node and the relay node, and where u(x)=1 if x>δ, and u(x)=0 otherwise.