Interference suppression during device-to-device communications

An apparatus comprising:

• at least one processor;
• and
• at least one memory including computer program code,
• wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform at least the following:
• select at least one terminal involved in a device-to-device communication to which interference caused by a transmission to at least one other terminal should be suppressed;
• choose a number of degrees of freedom from a predetermined number of degrees of freedom to be used to suppress interference towards the selected at least one terminal;
• use the remaining degrees of freedom from the predetermined number to increase signal quality to the at least one other terminal;
• perform precoding based on the chosen number of degrees of freedom and the remaining degrees of freedom;
• use at least the performed precoding, causing information to be transmitted to the at least one other terminal;
• form an interference cancellation portion of a transmission precoding matrix based on the chosen number of degrees of freedom;
• and
• form a beamforming portion of the transmission precoding matrix based on the remaining degrees of freedom.

A computer program, embodied on a non-transitory computer readable medium, the computer program, when executed in hardware, performs a process comprising:

• selecting at least one terminal involved in a device-to-device communication to which interference caused by a transmission to at least one other terminal should be suppressed;
• choosing a number of degrees of freedom from a predetermined number of degrees of freedom to be used to suppress interference towards the selected at least one terminal;
• using the remaining degrees of freedom from the predetermined number to increase signal quality to the at least one other terminal;
• performing precoding based on the chosen number of degrees of freedom and the remaining degrees of freedom;
• and
• using at least the performed precoding, causing information to be transmitted to the at least one other terminal,
• wherein performing precoding further comprises:
• forming an interference cancellation portion of a transmission precoding matrix based on the chosen number of degrees of freedom;
• and
• forming a beamforming portion of the transmission precoding matrix based on the remaining degrees of freedom.