Methods and apparatus for codebook subset restriction for two-dimensional advanced antenna systems

A user equipment (UE) configured for communication with an eNodeB (eNB) in a wireless network having two-dimensional antenna systems, the UE comprising:

• at least one antenna;
• and a processor coupled to the at least one antenna, the processor configured to:
• receive from the eNB an indication of one or more restricted subsets M of vertical precoding matrices or non-subset restricted precoding matrix indicator (PMI) selection modes, wherein M is less than a total number of vertical precoding matrices N in a codebook and wherein the indication of the restricted subset or the non-subset restricted PMI selection modes is configurable by the network and received form the eNB through a higher layer signalling in conjunction with one or more changed feedback configurations, the codebook comprising a plurality of vertical precoding matrices and horizontal precoding matrices;
• and feed back, via the at least one antenna, vertical precoding matrix indicators (V-PMI) to the eNB based on the restricted subset of vertical precoding matrices,
• wherein separate bitmaps are defined for subset restriction of Vertical and Horizontal precoders V and H individually, and
• wherein at least two bitmaps, AV and AH are with lengths NV and NH wherein the lengths are configured by higher layers.

An eNodeB (eNB) configured for communication with a plurality of user equipments (UEs) in a wireless network having two-dimensional antenna systems, the eNB comprising:

• at least one antenna;
• and a processor coupled to the at least one antenna, the processor configured to:
• transmit to a UE an indication of one or more restricted subsets M of vertical precoding matrices or non-subset restricted precoding matrix indicator (PMI) selection modes, wherein M is less than a total number of vertical precoding matrices N in a codebook and wherein the indication of the restricted subset or the non-subset restricted PMI selection modes is configurable by the network and received form the eNB through a higher layer signalling in conjunction with one or more changed feedback configurations, the codebook comprising a plurality of vertical precoding matrices and horizontal precoding matrices;
• and
• receive feedback from the UE, the feedback comprising a plurality of vertical precoding matrix indicators (V-PMI) based on the restricted subset of vertical precoding matrices,
• wherein separate bitmaps are defined for subset restriction of Vertical and Horizontal precoders V and H individually, and
• wherein at least two bitmaps, AV and AH are with lengths NV and NH wherein the lengths are configured by higher layers.