NR-PDCCH UE-Specific Cyclic Shifting for False Alarm Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In next-generation 5G new radio (NR) mobile communication networks, the Physical Downlink Control Channel (PDCCH) decoding process experiences a high false alarm rate due to the 'blind' decoding method, where user equipment (UE) must try multiple candidate channels, leading to inefficiencies in identifying the targeted NR-PDCCH, especially with UE-specific and common search spaces having different radio resource allocations.
Innovation Solution
Implementing UE-specific cyclic shifting of DCI information bits before or after Polar encoding, combined with CRC attachment and masking using a UE ID, reduces the false alarm rate by optimizing the search space and interleaving process, thereby improving the accuracy of NR-PDCCH decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blind decoding method is used for NR-PDCCH, then UE can identify targeted control channel, but false alarm rate increases due to multiple candidate channels
Solution Approach 1:
The patent applies preliminary action by performing UE-specific cyclic shifting of DCI information bits before Polar encoding and CRC attachment. This pre-processing step modifies the bit sequence in a UE-specific manner, creating a unique pattern that helps the UE distinguish its targeted PDCCH from other candidate channels during blind decoding, thereby reducing false alarm rates before the actual decoding process begins.
2Device complexity
If UE-specific search space is implemented, then search space size is reduced for each UE, but complexity of blind decoding process increases
Solution Approach 1:
The patent applies local quality by implementing UE-specific cyclic shifting that creates different local patterns in the DCI bit sequences for different UEs. Each UE experiences a unique cyclic shift pattern tailored to its specific configuration, which simplifies the detection process for that particular UE while maintaining overall system complexity management through localized rather than universal processing.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A method to improve the design of new radio physical downlink control channel (NR-PDCCH) transmission and to reduce the false alarm rate of NR-PDCCH blind decoding is proposed. The downlink control information (DCI) bits are carried by NR-PDCCH to be transmitted to UEs after CRC attachment, channel encoding, interleaving, and modulation. The proposed NR-PDCCH design is separated into two parts. In a first part, a UE-ID or RNTI is used to derive a CRC mask or a scrambling sequence for CRC attachment of the DCI bits. In a second part, a UE-specific ID is used to derive an interleaver before or after channel encoding of the DCI bits. If the interleaver is placed before channel encoding, it takes the form of a bit interleaver. If the interleaver is placed after channel encoding, it takes the form of a bit interleaver or a channel interleaver.