Multi-Dimensional Channel State Feedback Using Synthetic Codebook
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Solution Overview
Problem
Existing methods for feeding back channel state information in MIMO systems with multi-dimensional antenna arrays are inadequate, as they only relate to a single horizontal dimension and are not applicable for multi-dimensional antenna arrays with multiple dimension code word vectors.
Innovation Solution
A method and apparatus that determine a second orthogonal basis vector group and a group number based on a pre-defined first basis vector group, calculating a third orthogonal basis vector group for each data layer, and sending these to a base station to synthesize a multi-layer code word, reducing the number of feedback bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-layer code word technology is adopted for horizontal dimension only, then the feedback method is simple, but it becomes inapplicable for multi-dimensional antenna arrays with multiple dimension code word vectors
Solution Approach 1:
The patent segments the multi-dimensional code word feedback into two distinct parts: a first code word representing channel statistical central angle and offset value, and a second code word representing DFT vector selection. This segmentation allows each part to be optimized independently for multi-dimensional antenna arrays while maintaining manageable complexity in the feedback mechanism.
Solution Approach 2:
The patent extends the feedback method from single horizontal dimension to multi-dimensional space by introducing vertical dimension parameters and polarization dimension parameters. The first code word now encompasses central angles and offset values across multiple dimensions, enabling the system to handle multi-dimensional antenna arrays effectively.
2Loss of information
If traditional DFT code word feedback is used, then the feedback structure is simple, but the number of feedback bits increases for multi-layer data transmission
Solution Approach 1:
The patent uses partial action by selecting only the most significant components for feedback. Instead of feeding back complete channel state information, it feeds back the central angle, offset value, and DFT vector index which are the most critical parameters for reconstructing the channel state, thereby reducing feedback bits while maintaining reliability.
Solution Approach 2:
The patent creates a compact representation (copy) of the channel state information using code words that can be reconstructed at the receiver side. The first and second code words together form a compressed copy of the multi-dimensional channel state, reducing the amount of data that needs to be transmitted while preserving the essential information.
Data Source
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AI summary
The present invention discloses a method and an apparatus for feeding back channel state information, which relate to the field of communication network technologies, and can feed back channel state information in multi-layer data transmission based on a synthetic codebook in a multi-dimensional antenna array and reduce the number of feedback bits. In solutions provided in embodiments of the present invention, a second orthogonal basis vector group and a group number of the second orthogonal basis vector group are determined according to a pre-defined first basis vector group, a third basis vector group corresponding to each data layer is determined according to the second orthogonal basis vector group, then a second-level code word of each data layer is calculated separately, and the group number of the second orthogonal basis vector group, the third basis vector group corresponding to the each data layer, and the second-level code word corresponding to the each data layer are sent to a base station, so that the base station may synthesize a multi-layer code word. The solutions provided in the embodiments of the present invention are applicable when the channel state information is fed back.