Scheduling Request Transmission Collision Avoidance in 5G NR
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Solution Overview
Problem
In 5G New Radio (NR) networks, scheduling request (SR) resources face collisions with downlink data transmission and other uplink signals, leading to interference and degraded system performance, particularly in TDD systems, due to the lack of efficient SR transmission mechanisms and resource configuration strategies.
Innovation Solution
The implementation of UE behavior definitions for SR transmission, including skipping or deferring SR transmissions when collisions occur, and dynamic activation/deactivation of SR resources based on configured periodicities and numerologies, using Slot Format Indication (SFI) and radio resource control (RRC) signaling to avoid interference and optimize SR opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scheduling request (SR) transmissions are performed regularly according to configured periodicities, then SR reliability is improved, but interference with downlink data transmission and other uplink signals increases
Solution Approach 1:
The patent implements dynamic SR transmission behavior where the UE determines whether to transmit or skip SR based on real-time detection of collision with downlink signals (SSBs, CORESETs) and uplink signals (PUSCH, PUCCH, SRS). This dynamic adaptation resolves the contradiction by making SR transmission flexible rather than rigidly periodic, maintaining reliability through conditional transmission while reducing interference through collision avoidance.
Solution Approach 2:
The patent applies preliminary anti-action by checking for potential collisions before SR transmission. The UE detects whether SR resources collide with downlink signals (synchronization signal blocks, control resource sets) or uplink signals (physical uplink shared channel, physical uplink control channel, sounding reference signals) and proactively skips transmission when collision is detected, preventing interference before it occurs.
2Device complexity
If SR resources are configured with fixed periodicities, then resource allocation simplicity is improved, but adaptability to different service requirements (URLLC, eMBB) deteriorates
Solution Approach 1:
The patent implements multi-functionality by enabling the same SR resource configuration mechanism to serve different service requirements (URLLC with short periodicity for low latency, eMBB with longer periodicity for efficiency). The UE behavior definitions and collision detection mechanisms work universally across different numerologies and service types, allowing a single framework to adapt to diverse scenarios without requiring separate configuration systems.
Solution Approach 2:
The patent applies parameter changes by allowing SR periodicity to be dynamically adjusted based on service requirements and collision conditions. The system can change SR transmission parameters (periodicity, timing) according to the detected interference environment and service type, enabling adaptation from fixed to flexible periodicity configurations to meet varying URLLC and eMBB demands.
3Object-affected harmful factors
If SR transmissions are skipped or deferred to avoid collisions, then interference is reduced, but SR transmission delays increase
Solution Approach 1:
The patent implements skipping by allowing the UE to skip SR transmission in the current slot when collision with downlink or uplink signals is detected, and defer to the next available SR opportunity. This resolves the contradiction by accepting occasional delays (skipping) to avoid the more severe harm of continuous interference, maintaining overall system performance while preventing harmful collisions.
Data Source
AI summary
Methods and architectures for establishing an uplink control channel in a fifth generation (5G) or new radio (NR) wireless network includes transmitting scheduling requests (SRs) at sub-slot level/symbol-level periodicities and determining whether SR transmit opportunities will collide with downlink (DL) signals being received and halting an SR transmission if the timing of DL symbols overlap at an OFDM symbol with the SR transmission.