PDCCH DCI Processing for Blind Detection Under Polar Encoding
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Solution Overview
Problem
The nested encoding feature of polar codes in 5G systems leads to indistinguishable DCI formats, causing failures in blind detection, which affects the communication capability of terminal devices.
Innovation Solution
The method involves generating and processing downlink control information (DCI) using specific processing manners based on its format, including scrambling and bit reordering/resetting of CRC codes, RNTIs, and frozen bits, to enable correct decoding by terminal devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polar code nested encoding is used for DCI formats, then encoding efficiency is improved, but DCI format distinguishability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing distinct processing operations on DCI formats before encoding. Specifically, different DCI formats undergo different bit reordering operations (e.g., bit reversal, interleaving) and selective freezing of information bits at predetermined positions. These preliminary transformations ensure that even though polar code nested encoding is used, the encoded signals retain distinguishable characteristics that allow the receiver to correctly identify the original DCI format after decoding.
2Reliability
If blind detection is performed on multiple PDCCH locations, then DCI reception reliability is improved, but false alarm rate increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring search spaces with specific structures and patterns that enable efficient blind detection. The receiver uses predetermined knowledge about DCI format structures, resource allocation patterns, and coding schemes to perform targeted blind detection. This approach improves DCI reception reliability by focusing detection efforts on likely locations while reducing false alarms through structured verification processes.
Solution Approach 2:
The patent applies parameter changes by varying detection parameters such as aggregation levels, resource block allocations, and DCI format structures across different search spaces. The receiver adjusts detection thresholds and verification criteria based on the specific search space being examined, allowing reliable DCI detection while adapting to different channel conditions and reducing false alarm rates through parameter optimization.
Data Source
AI summary
This application provides an information transmission method, a network device, and a terminal device. The method includes: generating, by a network device, downlink control information DCI; determining, by the network device, a corresponding processing manner based on a format of the DCI; performing, by the network device, processing in the processing manner in an encoding process of the DCI; and sending, by the network device, the processed DCI over a physical downlink control channel PDCCH. The information transmission method provided in this application can resolve a problem of a failure in blind detection on DCI caused by a nested encoding feature of polar encoding. When a terminal device cannot determine the format of the DCI sent by the network device, the network device may use a mapping relationship, and the network device processes DCI of a format in a processing manner.