Method and apparatus for conveying precoding information in a mimo system

An apparatus in an access node, for conveying precoding information in a control message to a wireless device, the control message including information indicative of properties of an associated wireless data transmission between the access node and wireless device, comprising:

• processing circuitry configured to determine precoding parameters to be included in said control message;
• and
• encoding processing circuitry configured to encode control information bits in at least one precoding information field of the control message according to the determined precoding parameters based at least in part on a corresponding value in at least one payload size related field in the control message, wherein said corresponding field value is used to indicate that at least one of a first and second codeword is enabled, whereby an interpretation of said control information bits is determined based on whether one or two codewords are enabled

A method obtaining precoding information in a control message, the control message including information indicative of properties of an associated wireless data transmission between the access node and wireless device, comprising:

• receiving said control message including precoding parameters determined by the access node;
• and
• detecting said precoding parameters by decoding control information bits in at least one precoding information field of the control message according to the determined precoding parameters based at least in part on a corresponding value in at least one payload size related field in the control message, wherein said corresponding field value is used to indicate that at least one of a first and second codeword is enabled, whereby an interpretation of said control information bits is determined based on whether one or two codewords are enabled.

An apparatus for obtaining precoding information in a control message, the control message including information indicative of properties of an associated wireless data transmission between the access node and wireless device, comprising:

• a transceiver configured to receive said control message including precoding parameters determined by the access node;
• and
• detecting circuitry configured to detect said precoding parameters by decoding control information bits in at least one precoding information field of the control message according to the determined precoding parameters based at least in part on a corresponding value in at least one payload size related field in the control message, wherein said corresponding field value is used to indicate that at least one of a first and second codeword is enabled, whereby an interpretation of said control information bits is determined based on whether one or two codewords are enabled