| 摘要 |
A Network Node, a UE operable in a MIMO system and respective methods performed by the Network Node and UE are provided for determining a precoder of a Codebook to use for transmissions to the UE. The Network Node includes at least two transmitting antennas corresponding to two individual Ranks. The Network Node determines which precoders the UE shall evaluate, and transmits, to the UE, the determined precoders the UE shall evaluate. The Network Node receives, from the UE, a PMI, associated with one of the determined precoders, which the UE requests the Network Node to use for transmission to the UE; and the Network Node transmits, to the UE, data using the requested precoders. |
| 主权项 |
1. A method performed by a Network Node operable in a Multiple Input Multiple Output, MIMO, radio communication system for determining a precoder of a Codebook to use for transmissions in a cell to a User Equipment, UE, the Network Node comprising at least two transmitting antennas corresponding to at least two individual Ranks, the method comprising:
determining, based on an expected loss being less than an acceptable loss, a maximum number of precoders for individual ranks that the UE shall evaluate, wherein the expected loss is a loss in cell edge user throughput, in the cell that the Network Node transmits to the UE, that is expected for the determined maximum number of precoders for the individual ranks, and wherein the acceptable loss is a level of loss in cell edge user throughput, in the cell, that is predetermined to be acceptable; determining, for the individual Ranks, which precoders, out of a plural total number of predefined precoders per individual rank in the codebook, that the UE shall evaluate, wherein the number of precoders to evaluate for each individual rank is constrained to not be greater than the determined maximum number of precoders and wherein the determined maximum number of precoders is less than the plural total number of the predefined precoders per individual rank in the codebook; transmitting, to the UE, the determined precoders the UE shall evaluate for the individual Ranks; receiving, from the UE, a Precoding Matrix Indicator, PMI, associated with one of the determined precoders, which the UE requests the Network Node to use for transmission to the UE for the individual Ranks; and transmitting, to the UE, data using the requested precoders for the individual Ranks. |
