A single receive chain of a MIMO receiver is activated during a low power listen mode. Upon detecting a legacy short training field (L-STF) in a received packet, the single receive chain performs a first frequency estimation, and activates one or more additional receive chains of the MIMO receiver. The MIMO receiver uses maximal ratio combining (MRC) to receive the signal using the first receive chain and the one or more additional activated receive chains, wherein the MRC is based, at least in part, on the first frequency estimation. The MIMO receiver may determine whether the received packet is a high throughput/very high throughput (HT/VHT) packet, and if not, deactivate the one or more additional receive chains. In one alternative, the additional receive chains are not activated until determining that a HT/VHT packet has been received.