Multi-user-mimo detection using space-time equalization

An apparatus comprising:

• a plurality of receive downconverters each coupled to a corresponding one of a plurality of antennas to produce a plurality of antenna-specific receive signals potentially representing a wireless transmission received from each of one or a plurality of devices;
• a processor coupled to the plurality of receive downconverters, wherein the processor is configured to perform operations including:
• detecting from the plurality of antenna-specific receive signals a transmission from a first device;
• performing a synchronization and a cyclic prefix removal operation from the plurality of antenna-specific receive signals to produce a time domain first device signal;
• converting the time domain first device signal to a frequency domain first device signal;
• computing an estimated channel response matrix for the first device based on the frequency domain first device signal;
• computing a null space matrix based on the estimated channel response matrix for the first device;
• using the null space matrix, canceling from the frequency domain first device signal any contribution associated with a transmission received at the plurality of antennas from the first device to produce a second frequency domain signal;
• converting the second frequency domain signal to the time domain to produce a second time domain signal;
• detecting from the second time domain signal a transmission from a second device;
• configuring a first space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover the transmission from the first device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the first device in the plurality of antenna-specific receive signals;
• and
• based on the second time domain signal, configuring a second space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover the transmission from the second device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the second device in the plurality of antenna-specific receive signals.

One or more non-transitory computer readable storage media encoded with instructions that, when executed by a processor, cause the processor of a wireless device to perform operations including:

• obtaining a plurality of antenna-specific receive signals potentially representing a wireless transmission received at a plurality of antennas from each of one or a plurality of devices;
• detecting from the plurality of antenna-specific receive signals a transmission from a first device;
• performing a synchronization and a cyclic prefix removal operation from the plurality of antenna-specific receive signals to produce a time domain first device signal;
• converting the time domain first device signal to a frequency domain first device signal;
• computing an estimated channel response matrix for the first device based on the frequency domain first device signal;
• computing a null space matrix based on the estimated channel response matrix for the first device;
• using the null space matrix, canceling from the frequency domain first device signal any contribution associated with a transmission received at the plurality of antennas from the first device to produce a second frequency domain signal;
• converting the second frequency domain signal to the time domain to produce a second time domain signal;
• detecting from the second time domain signal a transmission from a second device;
• configuring a first space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover the transmission from the first device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the first device in the plurality of antenna-specific receive signals;
• and
• based on the second time domain signal, configuring a second space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover the transmission from the second device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the second device in the plurality of antenna-specific receive signals.