Apparatus and method for spatial multiplexing with backward compatibility in a multiple input multiple output wireless communication system

A receiver apparatus in a Multiple Input Multiple Output (MIMO) wireless communication system, the apparatus comprising:

• an estimator for estimating a channel for each antenna between the receiver and a transmitter;
• a determining unit for determining whether a channel environment between a first Receive (Rx) antenna and the transmitter comprises a Line Of Sight (LOS) environment by using information on the channel;
• an LOS detector for detecting a first signal from a signal received through the first Rx antenna when the channel environment between the first Rx antenna and the transmitter comprises the LOS environment, and for detecting a second signal according to a Successive Interference Cancellation (SIC) scheme;
• and
• a Non Line Of Sight (NLOS) detector for detecting the first signal and the second signal from signals received through the first Rx antenna and a second Rx antenna according to a Zero Forcing (ZF) scheme, when the channel environment between the first Rx antenna and the transmitter comprises an NLOS environment.