Adaptive CRC Length Selection for Wireless Channel Reliability
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in managing cyclic redundancy check (CRC) length, particularly in LTE, where a fixed CRC length for all data channels is inefficient, leading to increased overhead for less demanding traffic types like VoIP, and higher false alarm probabilities in 5G requirements for ultra-high reliability.
Innovation Solution
The method involves determining the CRC field size based on explicit or implicit indications for each transmission, allowing for variable CRC lengths (e.g., 24-bit or 36-bit) depending on the type of traffic, data size, and specific channel conditions, using different formulas and generator polynomials for calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed CRC length is used for all data channels, then system complexity is reduced, but overhead increases for less demanding traffic types and false alarm probability increases for high reliability requirements
Solution Approach 1:
The patent implements dynamic CRC length selection where the CRC field size is adapted based on traffic type, data size, and channel conditions. Different CRC lengths (e.g., 16-bit, 24-bit, 32-bit) are selected dynamically to match the reliability requirements of different services, allowing the system to optimize between overhead and error detection capability rather than using a fixed length for all channels.
Solution Approach 2:
The patent changes the CRC field length parameter according to specific communication needs. By modifying this parameter based on traffic characteristics and channel conditions, the system achieves optimal performance for different service types while maintaining manageable complexity through standardized selection criteria.
2Reliability
If a longer CRC length is used, then error detection accuracy is improved, but overhead increases for less demanding traffic types
Solution Approach 1:
The patent applies different CRC lengths to different data channels based on their specific requirements. High-reliability channels (e.g., control channels, ultra-reliable traffic) receive longer CRC fields for enhanced error detection, while less demanding channels (e.g., voice traffic) use shorter CRC fields to minimize overhead. This localized optimization ensures each channel gets the appropriate level of error protection without unnecessary overhead.
Solution Approach 2:
The system dynamically selects CRC length based on real-time factors including traffic type, data size, and channel conditions. This dynamic adaptation allows the system to use longer CRC fields only when and where needed for high reliability requirements, while using shorter fields for routine traffic to minimize overhead.
3Quantity of substance
If a shorter CRC length is used, then overhead is reduced, but false alarm probability increases for high reliability requirements
Solution Approach 1:
The patent applies appropriate CRC lengths to specific channels based on their false alarm sensitivity. Channels with high false alarm risk (e.g., control channels, scheduling information) are assigned longer CRC fields to reduce false alarm probability, while data channels with robust higher-layer error handling can use shorter CRC fields to minimize overhead.
Solution Approach 2:
The system dynamically adjusts CRC length to balance overhead and false alarm probability based on channel conditions and traffic characteristics. When channel conditions deteriorate or traffic requires higher reliability, the system increases CRC length to reduce false alarms, and reduces CRC length when conditions are favorable.
Data Source
AI summary
Certain aspects of the present disclosure provide methods and apparatus for managing cyclic redundancy check field lengths in wireless communications. An exemplary method generally includes determining a size of a cyclic redundancy check (CRC) field, from a plurality of possible sizes for a given type of physical wireless channel, to be used for a transmission to be sent on the physical wireless channel, and performing communication based on the transmission on the physical wireless channel with the CRC field of the determined size.