METHODS AND ARRANGEMENTS FOR FEEDING BACK CHANNEL STATE INFORMATION

摘要

A method and an arrangement (600) in a user equipment (140) for quantizing channel state information in a coordinated multi-point transmission radio communication system (100). A dominant path is between the user equipment (140) and a first network node (110) and a non-dominant path is between the user equipment (140) and a second network node (120, 130). A ratio of the non-dominant path channel response, such as fast fading, to the dominant path channel response is quantized by using a codebook disclosed herein. A method and an arrangement (400) for generating a codebook by applying a log squared error distortion measure in an iterative algorithm. A method and an arrangement (900) in a user equipment (140) for allocating available bits among at least two quantized ratios in a channel state information feedback procedure. The bits are allocated by means of selecting (270) at least one codebook based on statistic properties, such as path gain, of the non-dominant path.