Techniques are disclosed for determining which channelization codes are used for an interfering HS-PDSCH transmission without knowing whether a neighboring UE targeted by that transmission has had its 64QAM capability activated by higher layer signaling. The average amplitude is measured for each of several possible groups of channelization codes for each of one or more nearby UEs that might be the targets of interfering HS-PDSCH messages. Testing whether the amplitude is approximately the same across the codes in a possible combination of channelization codes yields a metric value that indicates whether that particular combination of codes is likely to be transmitted to a given UE. A second metric that detects the most likely modulation for possible groups of channelization codes is also calculated. The metrics are combined to determine which combination of channelization codes and modulation scheme is most likely being used for addressing the neighboring UE.