Dual CRC Scrambling for LTE Control Channel False Detection
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Solution Overview
Problem
The existing Cyclic Redundancy Check (CRC) encoding in LTE and LTE-A communication systems faces challenges in improving the false detection capability of control channel and payload information, particularly due to redundant Carrier Indication Fields and limited error detection mechanisms.
Innovation Solution
The proposed solution involves generating and scrambling two CRCs for a message, where the first CRC is scrambled by a Carrier Indication Field (CIF) and the second CRC is scrambled by a Cell-Radio Network Temporary Identifier (C-RNTI), enhancing error detection capabilities and reducing false detection probabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single CRC is used for error detection in control channel messages, then the device complexity is low, but the false detection capability is insufficient
Solution Approach 1:
The single CRC mechanism is segmented into two independent CRC encoders (first CRC encoder and second CRC encoder), each generating a separate CRC code for different aspects of error detection. This segmentation allows the system to detect both channel errors and format errors independently, improving false detection capability while maintaining manageable complexity through modular design
Solution Approach 2:
The first CRC code is nested within the control channel message structure, and the second CRC code is nested after the first CRC. This nested arrangement allows multiple layers of error detection without significantly increasing overall system complexity, as each CRC is integrated into the existing message framework
2Reliability
If multiple CRCs are generated and scrambled for enhanced error detection, then the reliability improves, but the processing time increases
Solution Approach 1:
The first CRC is generated and scrambled preliminary to the second CRC generation. This preliminary action allows the first error detection layer to be established before the second layer, enabling early detection of certain error types and potentially avoiding unnecessary processing of obviously erroneous messages
Solution Approach 2:
The two CRC encoding operations are performed in continuous sequence without interruption, maintaining the flow of message processing. The first CRC encoder operates continuously on incoming messages, and the second CRC encoder immediately follows, ensuring that the enhanced error detection does not introduce significant processing delays
Data Source
AI summary
A method and apparatus for generating a Cyclic Redundancy Check (CRC) encoded message in a communication system are provided. The method includes generating the message, generating a first CRC for the message, generating a second CRC for the message, scrambling the first CRC by a first bit sequence of the message, and scrambling the second CRC by a second bit sequence of the message. The apparatus includes a message generator, a first CRC encoder, and a second CRC encoder. The message generator generates a message. The first CRC encoder generates a first CRC for the message, and scrambles the first CRC by a first bit sequence of the message. The second CRC encoder generates a second CRC for the message, and scrambles the second CRC by a second bit sequence of the message.