Performance of Linear MIMO Receiver Using Null-Space Expansion Technique over Time-Variant Channels

The transmission performance deteriorates if the combining weights for interference suppression are fixed within a packet during signal separation in linear MIMO reception, since the propagation path changes with time in mobile communications. To solve this problem, we apply the null-space expansion technique, which improves transmission performance by forming additional nulls to suppress inter-stream interference using antenna degrees of freedom. In this study, we consider acquiring the past channel information for the null-space expansion technique from multiple positions in a packet. Error rate performance is evaluated using computer simulations when combining weights generated by this technique are applied to the entire packet.