Polar-Coded Control Channels With Frozen-Bit Scheduling
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Solution Overview
Problem
Current wireless communication systems, particularly 5G networks, face challenges in reducing control channel overhead, which affects performance due to high data traffic demands and complex channel conditions.
Innovation Solution
The use of polar codes to encode control channel information, where bit locations are categorized as frozen or non-frozen based on reliability, allowing scheduling information to be conveyed through frozen bits, thereby reducing the size of control channel information blocks and minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coding schemes are used for control channels, then implementation is simpler, but control channel overhead is higher and reliability is lower
Solution Approach 1:
The control channel information is segmented into frozen bits and non-frozen bits based on reliability requirements. Frozen bits are used for high-priority control information requiring high reliability, while non-frozen bits carry lower-priority scheduling data. This segmentation allows differential protection strategies for different information types, improving overall control channel reliability without uniformly increasing complexity across all bits.
Solution Approach 2:
Different portions of the control channel are assigned different quality levels through the polar code structure. Specifically, certain bit positions are designated as frozen bits with error-free protection, while other positions are non-frozen bits that may contain errors. This local quality differentiation allows the system to guarantee reliability for critical control information while accepting lower reliability for less critical scheduling data, thereby improving overall system reliability without proportionally increasing complexity.
2Adaptability or versatility
If more control channel information is transmitted, then more scheduling flexibility is achieved, but control channel overhead increases
Solution Approach 1:
Scheduling information is extracted from the main control channel information block and placed into the frozen bits of the polar code. By taking out the scheduling data and embedding it in the frozen bit positions, the system conveys scheduling flexibility information without increasing the overall control channel overhead, as the frozen bits are already allocated for reliability-critical control information.
Solution Approach 2:
The patent merges multiple functions into the control channel transmission: high-priority control information, scheduling data, and error protection are all combined within the same polar code structure. By merging scheduling information with control channel transmissions in the frozen bits, the system achieves scheduling flexibility without requiring separate overhead channels, thereby maintaining efficient resource utilization.
3Reliability
If frozen bits are used for high-priority information, then reliability improves, but the amount of scheduling data that can be conveyed decreases
Solution Approach 1:
The polar code structure preliminarily allocates frozen bit positions before transmission, designating specific bit locations for high-priority control information that requires maximum reliability. By performing this preliminary assignment of frozen bits to critical information, the system ensures that the most important control data receives the highest level of protection, while non-frozen bits are reserved for scheduling information that can tolerate some error probability.
Solution Approach 2:
The patent utilizes the dimensional structure of polar codes by assigning different reliability dimensions to different bit positions. Frozen bits represent a high-reliability dimension for control information, while non-frozen bits represent a lower-reliability dimension for scheduling data. This dimensional differentiation allows the system to maintain high reliability for critical information while still conveying scheduling information through the available non-frozen bit positions, effectively managing the trade-off between reliability and information capacity.
Data Source
AI summary
Programming of frozen bits of first stage control channel information block enables scheduling information to be included for the second stage of the control channel information. By including some of the scheduling information for the second stage in the first stage frozen bits, the size of the first stage information blocks can be reduced, reducing the overhead required to transmit control information for the traffic channel. In an embodiment, the frozen bits can convey scheduling information that is lower priority than the scheduling information conveyed in the non-frozen bits of the first stage control channel information block. In another embodiment, the frozen bits can include parity bits, or cyclic redundancy check bits that are masked with the scheduling information.