EPDCCH Candidate Allocation Using Carrier Offsets
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Solution Overview
Problem
In wireless communications, the simultaneous transmission of multiple EPDCCHs in the same resource set leads to overlapping candidate allocations, resulting in EPDCCH blocking and unreliable control information transmission due to the inability of multiple EPDCCHs to occupy distinct candidates at the same aggregation level.
Innovation Solution
An enhanced method for determining EPDCCH candidates across multiple carriers, where candidates are staggered using a candidate offset, allowing each carrier to occupy unique candidates within the same aggregation level, preventing overlap and enabling successful transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same algorithm is used to determine EPDCCH candidate allocation for multiple carriers, then the allocation process is simple and uniform, but EPDCCH candidates of different carriers overlap completely at the same aggregation level, causing blocking and unreliable transmission
Solution Approach 1:
The patent applies local quality by introducing carrier-specific offsets (nCellindex) into the candidate allocation formula. Each carrier is assigned a unique offset value, causing EPDCCH candidates for different carriers to be distributed at different positions within the same aggregation level. This local differentiation ensures that while the overall allocation algorithm remains uniform, each carrier receives distinct candidate locations, preventing overlap and blocking.
2Device complexity
If EPDCCH candidates for multiple carriers are allocated using identical patterns, then the system complexity is reduced, but some EPDCCHs are discarded due to overlapping candidates, resulting in blocking
Solution Approach 1:
The patent changes the allocation parameters by incorporating carrier-specific offset values (nCellindex) into the candidate determination formula. This parameter modification transforms the allocation pattern from identical for all carriers to carrier-specific patterns. The formula ECCE(m, L, Cellindex) = (Yp,k + m × Mp(L) + nCellindex) mod NECCE,p,k ensures that each carrier's candidates are shifted relative to others, preventing overlaps while maintaining manageable system complexity.
3Quantity of substance
If multiple EPDCCHs share the same candidate locations, then resource utilization is maximized, but control information transmission becomes unreliable due to blocking
Solution Approach 1:
The patent segments the EPDCCH candidate space by introducing carrier-specific offsets that divide the candidate pool into carrier-specific subsets. Each carrier's EPDCCH is allocated to distinct segments (candidates) within the aggregation level, preventing multiple carriers from sharing the same candidate locations. This segmentation ensures reliable transmission by guaranteeing that each carrier has dedicated, non-overlapping candidates, while still utilizing the available resource space efficiently.
Data Source
AI summary
The present disclosure discloses a physical downlink control channel (PDCCH) candidate determining method and device, and relates to the field of wireless communications. The method includes: determining a PDCCH resource set p in a subframe k, where the PDCCH resource set p includes NECCE,p,k=q×r control channel elements (CCEs), a PDCCH candidate of an EPDCCH with an aggregation level being L corresponds to L CCEs having consecutive reference numerals, and the PDCCH candidate is capable of carrying a PDCCH; and determining the number of PDCCH candidates at the aggregation level L of a carrier corresponding to an index Cellindex and an CCE corresponding to each PDCCH candidate, where the CCE corresponding to each PDCCH candidate at the aggregation level L is related to the index Cellindex.