PDCCH Reliability Using Repetitions Across Multiple CORESETs
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Solution Overview
Problem
Existing PDCCH transmission in cellular communications systems faces challenges in reliability, particularly in scenarios involving multiple Transmission/Reception Points (TRPs), where channel blocking or deep fading can lead to increased Block Error Rates (BLER), and existing methods like CCE interleaving, PDCCH repetition without soft combining, and soft combining do not consistently provide improved performance across all conditions.
Innovation Solution
Implementing PDCCH repetitions over multiple Control Resource Sets (CORESETs) with either different or same channel encoding, where each repetition is transmitted from a different TRP or beam, allowing for decoding based on both repetitions, enhancing reliability through diverse transmission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCCH transmission uses single TRP, then device complexity is low, but reliability deteriorates due to channel blocking or deep fading
Solution Approach 1:
The PDCCH transmission is segmented into multiple independent transmissions from different TRPs. Each TRP transmits the same DCI information through separate PDCCH candidates in different CORESETs, creating diversified transmission paths that can independently overcome channel blocking or fading affecting any single path.
Solution Approach 2:
The system changes the transmission parameters by introducing multiple TRPs with different spatial locations and different CORESET configurations. This parameter diversification ensures that not all transmissions experience the same channel conditions, thereby improving reliability without requiring complex adaptive modulation or coding schemes.
2Reliability
If PDCCH repetition is implemented without soft combining, then decoding complexity is reduced, but reliability improvement is insufficient in challenging channel conditions
Solution Approach 1:
The system dynamically adapts the combining strategy based on channel conditions and configuration. When soft combining is configured, the UE combines multiple PDCCH candidates to improve reliability; when not configured, the UE uses simpler individual decoding. This dynamic approach allows the system to optimize between reliability and complexity based on actual needs.
Solution Approach 2:
The network configuration acts as an intermediary that controls whether soft combining is performed. Through RRC configuration parameters, the network can enable or disable soft combining functionality, allowing flexible control over the complexity-reliability tradeoff without requiring complex real-time decision-making at the UE side.
3Reliability
If multiple PDCCH candidates are transmitted over multiple CORESETs, then reliability is improved through diverse paths, but device complexity increases
Solution Approach 1:
The reception process is segmented into monitoring multiple independent CORESETs, each with its own PDCCH candidates. This segmentation allows the UE to independently process each CORESET and combine results, simplifying the overall reception logic while achieving diversity through multiple transmission paths.
Solution Approach 2:
The UE is designed with universal reception capability that can handle PDCCH monitoring in multiple CORESETs using the same decoding algorithms. This multi-functionality allows the UE to efficiently process diversified transmissions without requiring separate specialized processing paths for each CORESET.
Data Source
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AI summary
Systems and methods are disclosed herein for improving the reliability of a physical downlink control channel (PDCCH) transmission and reception. In one embodiment, a method performed by a wireless communication device for reception of PDCCH repetitions over multiple control resource sets (CORESETs) in a cellular communications system comprises receiving a configuration of a first CORESET and a second CORESET. The method further comprises receiving, from one or more network nodes, a first repetition of a PDCCH carrying downlink control information (DCI) in the first CORESET and a second repetition of the PDCCH carrying the same DCI in the second CORESET, wherein the first and second repetitions of the PDCCH have either: (a) different channel encoding or (b) a same channel encoding. The method further comprises decoding the DCI based on the first repetition of the PDCCH and/or the second repetition of the PDCCH.