CRC Register Initialization for DCI Size Ambiguity

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Solution Overview

Problem

Current wireless communication technologies face challenges in accurately determining control information for payloads with leading zeroes, leading to ambiguity and potential false alarms due to identical CRC values generated by different payload sizes, which affects decoding efficiency and throughput.

Innovation Solution

The method involves initializing the CRC register with a non-zero value or using a CRC mask affected by the DCI size, ensuring that the CRC value is distinct for different payload sizes, thereby reducing ambiguity and improving decoding success rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If CRC register is initialized with zero value, then decoding process is simplified, but ambiguity occurs for payloads with leading zeroes causing false alarms

Engineering Contradiction:
ImproveCRC initialization complexityVSAvoidDecoding accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the initialization parameter of the CRC register from zero to a non-zero value (such as all ones). This parameter change ensures that payloads with leading zeroes produce distinct CRC values from payloads without leading zeroes, thereby eliminating the ambiguity and false alarms while maintaining a relatively simple decoding process.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If payload size is variable, then adaptability to different data lengths is improved, but size ambiguity arises when payloads have leading zeroes

Engineering Contradiction:
ImprovePayload size adaptabilityVSAvoidPayload size determination accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

By changing the CRC initialization parameter to a non-zero value, the system maintains variable payload size adaptability while improving payload size determination accuracy. The non-zero initialization ensures that the CRC output reflects the actual payload content including leading zeroes, allowing accurate distinction between different payload sizes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the CRC value as feedback to determine payload size. By initializing the CRC register with a non-zero value, the CRC calculation produces distinct feedback values for different payload sizes, enabling the receiver to accurately determine the payload size based on the CRC result without ambiguity.

Inventive Principle:
Principle #23Feedback

3Reliability

If CRC value is used for error detection, then reliability is improved, but false alarms occur when different payload sizes produce identical CRC values

Engineering Contradiction:
ImproveError detection capabilityVSAvoidFalse alarm rate
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent changes the CRC initialization parameter from zero to a non-zero value. This parameter change ensures that different payload sizes produce distinct CRC values, eliminating false alarms while maintaining the error detection capability. The non-zero initialization creates a one-to-one mapping between payload content and CRC values.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3711206B1Techniques and apparatuses for removing ambiguity on the size of control information with leading zeroes
Publication Date: 2024.07.24 QUALCOMM INC
  • EP3711206B1 patent drawingFigure 1
  • EP3711206B1 patent drawingFigure 2
  • EP3711206B1 patent drawingFigure 3A

AI summary

Certain aspects of the present disclosure generally relate to wireless communication, with focus on reducing problems of downlink control information, DCI, size ambiguity when polar coding is used. In some aspects, a user equipment may receive a communication that includes DCI, wherein a size of the DCI affects a cyclic redundancy check, CRC, value associated with the communication; and determine the DCI or the size of the DCI based at least in part on the CRC value. Numerous other aspects are provided.