Precoding Vector Signaling for Wireless Communication Overhead Reduction

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Solution Overview

Problem

In wireless communication systems, particularly in NR systems, frequency selective precoding for uplink transmission increases signaling overhead and varies the payload size of downlink control signaling with the number of subbands, leading to inefficiencies in multi-antenna transmission.

Innovation Solution

A method involving a User Equipment (UE) that receives and transmits radio signals with scheduling information containing fields for determining precoding vectors, where the indexes of these vectors are indicated completely for some subbands and differentially for others, reducing signaling overhead by leveraging channel correlation between subbands, thereby maintaining a fixed payload size regardless of frequency-domain resource changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If codebook based precoding is used for multi-antenna transmission in NR systems, then transmission performance is improved, but signaling overhead increases

Engineering Contradiction:

Improvetransmission performanceVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The bandwidth is divided into multiple subbands, and precoding information is indicated separately for each subband. This allows frequency-selective precoding to be implemented, improving transmission performance by adapting to frequency-selective fading, while the segmentation enables efficient signaling through differential encoding between adjacent subbands

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station pre-configures codebooks at both the base station and UE sides, containing predefined precoding vectors. This preliminary preparation allows for efficient precoding indication during data transmission, reducing real-time signaling overhead while maintaining accurate precoding for improved transmission performance

Inventive Principle:

Principle #10Preliminary action

2Reliability

If frequency selective precoding is implemented by indicating codeword information of each subband, then transmission performance is improved, but payload size of downlink control signaling varies with the number of subbands

Engineering Contradiction:

Improvetransmission performanceVSAvoidpayload size variation

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Codebooks are pre-configured at both base station and UE sides with predefined precoding vectors for different subbands. This preliminary preparation enables efficient precoding indication without requiring dynamic transmission of complete codeword information for each subband, stabilizing payload size

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of transmitting complete codeword information for each subband, the patent uses differential encoding that transmits only the difference or offset from a reference subband. This copying approach reduces the amount of information that needs to be signaled, maintaining fixed payload size while still achieving frequency-selective precoding for improved transmission performance

Inventive Principle:

Principle #26Copying

3Measurement precision

If complete codeword information is indicated for each subband, then precoding precision is improved, but signaling overhead increases

Engineering Contradiction:

Improveprecoding precisionVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

Codebooks are pre-configured at both base station and UE sides with predefined precoding vectors. This preliminary preparation allows the system to achieve precise precoding by selecting from pre-optimized vectors without needing to signal complete codeword information, thus reducing signaling overhead while maintaining precoding precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs differential encoding where only the difference between adjacent subband precoding information is transmitted. This copying approach preserves the precision of precoding vectors by maintaining their relationship to reference values while significantly reducing the amount of signaling overhead compared to transmitting complete codeword information for each subband

Inventive Principle:

Principle #26Copying

Data Source

PatentUS11218193B2Method and device in UE and base station used for wireless communication

Publication Date: 2022.01.04 APOGEE NETWORKS LLC

AI summary

A method and a device are provided in a User Equipment (UE) and a base station for wireless communication. The UE receives a first signaling and transmits a first radio signal. The first signaling includes K first field(s) and K second field(s), the K first field(s) is(are) used for determining K first-type vector(s) respectively, and the K first-type vector(s) is(are) one-to-one corresponding to K second-type vector group(s) or K second field(s); a correlation between any one second-type vector in each second-type vector group(s) and a corresponding first-type vector is related to a corresponding second field; the first radio signal includes a second radio signal and a third radio signal; the K first-type vector(s) and the K second-type vector group(s) are used for determining multi-antenna related transmissions of the second radio signal and the third radio signal respectively; the second radio signal and the third radio signal occupy orthogonal frequency-domain resources.