5G NR PDCCH Decoding via CCE Interference Randomization
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Solution Overview
Problem
The existing designs for Physical Downlink Control Channel (PDCCH) transmission in 5G NR systems face significant interference and decoding failures due to overlapping CCE transmission between nearby sectors, leading to degraded RACH success rates and throughput, which cannot be resolved by increasing transmission power or separating PDCCH in time.
Innovation Solution
The system employs CCE randomization by configuring differing Start CCE indexes for CORESETs across sectors, maintaining orthogonality between CORESET-0 and CORESET-1 to minimize interference and improve PDCCH decoding, by offsetting CCE indexes based on aggregation levels and interleaved or non-interleaved mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCCH transmission power is increased to improve decoding, then decoding reliability is improved, but system-level interference increases
Solution Approach 1:
The patent changes the parameter of CCE index allocation by introducing an offset based on aggregation level. Different aggregation levels (AL1, AL2, AL4, AL8) are mapped to different CCE index ranges through the formula: start_CCE_index = floor(aggregation_level / 2) * 2. This parameter change allows PDCCH transmissions with different aggregation levels to use different CCE resources, reducing collisions and improving decoding reliability without increasing transmission power.
2Object-generated harmful factors
If PDCCH transmission is separated in time to reduce interference, then interference is reduced, but system-level throughput decreases
Solution Approach 1:
Instead of separating PDCCH transmissions in time (one dimension), the patent introduces a new dimension for resource differentiation: the CCE index dimension. By offsetting CCE indexes based on aggregation level, the patent creates frequency-domain separation within the same time slot, allowing simultaneous transmissions without interference while maintaining high throughput.
3Productivity
If CCE allocation is done in overlapping frequency locations to maximize resource utilization, then resource efficiency is improved, but PDCCH decoding accuracy degrades due to interference
Solution Approach 1:
The patent applies local quality by making CCE allocation dependent on the local property of aggregation level. Each aggregation level gets a specific CCE index range offset, creating localized resource allocation patterns. This ensures that PDCCH transmissions with different aggregation levels use different local CCE resources, reducing interference while maintaining overall resource efficiency.
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AI summary
A method that uses CCE randomization to improve the detectability of PDCCH transmission in 5G NR applications to increase the RACH success rate and throughput at the system level. The method includes allocating PDCCH CCE for CORESETs for nearby sectors to be separated by frequency and/or by time providing differing Start CCE indexes for CORESETs according to the aggregation levels in PDCCH transmission.