PUCCH HARQ Resource Allocation for 5G NR Interference Mitigation
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Solution Overview
Problem
Current systems face significant degradation in Downlink throughput due to Inter-cell Interference (ICI) caused by PUCCH HARQ resource collisions across sectors, particularly at cell edges, leading to increased NACK detection and reduced PUCCH HARQ detection probability.
Innovation Solution
The system allocates PUCCH HARQ resources by configuring a unique Physical Resource Block (PRB) index and Cyclic Shift Index for each sector based on Physical Cell Identity (PCI), ensuring orthogonal transmission across nearby sectors by separating resources in frequency and cyclic shift, and reserving a symbol in a slot for PUCCH transmission that is not used for PUSCH in other cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PUCCH HARQ resources are assigned in the same frequency locations and cyclic shifts across sectors, then resource allocation is simplified, but inter-cell interference increases causing significant degradation in DL throughput
Solution Approach 1:
The patent applies local quality by configuring different PUCCH HARQ resources for different sectors. Specifically, each sector is assigned unique combinations of physical resource block (PRB) indices and cyclic shift values, so that while the overall resource allocation mechanism remains standardized, the actual resource characteristics vary locally per sector to avoid interference.
Solution Approach 2:
The patent changes key parameters of PUCCH HARQ resources including PRB index, cyclic shift value, and time slot allocation. By modifying these parameters differently across sectors, the system maintains resource allocation simplicity while eliminating inter-cell interference that would otherwise degrade throughput.
2Object-affected harmful factors
If PUCCH HARQ resources are positioned in different time positions in different sectors, then interference from same-slot PUCCH is reduced, but interference from nearby cell PUSCH still occurs and strict resource planning becomes difficult
Solution Approach 1:
The patent moves from one-dimensional time-based separation to multi-dimensional resource separation by introducing frequency domain (different PRB indices) and code domain (different cyclic shifts) dimensions. This allows interference avoidance without requiring strict time-position planning, as resources are separated across multiple dimensions simultaneously.
3Productivity
If PUCCH HARQ detection probability is increased, then DL throughput improves, but current methods and system configurations do not allow for increased detection probability due to resource collision
Solution Approach 1:
The patent converts the potentially harmful effect of resource collision into a benefit by systematically assigning different resource parameters to different sectors. This transforms what would be interfering resources into orthogonal, non-interfering resources, thereby improving both detection probability and throughput simultaneously.
Data Source
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AI summary
A Radio Access Network (RAN) system includes a group of cell sites where each cell site includes multiple sectors, and each sector communicates with UE, the system including a Radio Resource Controller (RRC) in Central Unit (CU) controlling PUCCH resources for the sectors, and a Media Access Control (MAC) Scheduler in each sector allocating resources for PUCCH HARQ transmissions in an orthogonal manner separated in time or frequency or cyclic shift to minimize the inter-carrier interference across the sectors to improve system throughput.