NR-U COT Downlink Uplink Switching via Active Channel Indication
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Solution Overview
Problem
Current wireless communication systems face interference and communication inefficiencies due to the need for medium-sensing procedures in shared radio frequency spectrum, particularly when multiple network operating entities contend for access, leading to increased signaling overhead and latency.
Innovation Solution
Implementing a method for identifying a within-channel occupancy time (COT) scheduled downlink-uplink switching configuration and using active channel indications to facilitate coordinated communications between network nodes on shared communication channels, allowing for multiple downlink-uplink switches within a COT without the need for continuous medium-sensing procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If medium-sensing procedures are performed in shared radio frequency spectrum, then interference can be detected and avoided, but communication latency and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by performing medium-sensing procedures only once at the beginning of a Channel Occupancy Time (COT) period, rather than continuously before each transmission. The gNB initiates a COT by performing LBT, and once the COT is established, multiple downlink and uplink transmissions can occur within this COT without requiring repeated medium-sensing, thus reducing latency while maintaining interference detection reliability.
Solution Approach 2:
The patent enables continuous useful action by allowing multiple downlink-uplink switching opportunities within a single COT. Once the medium is acquired, the gNB can continuously schedule transmissions across multiple slots and frames without interruption from repeated sensing procedures, maximizing spectrum utilization while minimizing the time lost to sensing operations.
2Productivity
If multiple downlink-uplink switching opportunities are supported within a COT, then communication efficiency improves, but the complexity of channel management increases
Solution Approach 1:
The patent applies segmentation by dividing the COT into multiple distinct downlink and uplink slots, organized in a structured pattern. Each slot is clearly defined with specific timing and resource allocation, allowing multiple switching opportunities while maintaining manageable complexity through systematic organization rather than ad-hoc channel management.
Solution Approach 2:
The patent implements dynamics by enabling flexible downlink-uplink switching within the COT based on traffic demands. The gNB can dynamically allocate resources across multiple slots and frames, adapting the communication pattern to changing conditions while maintaining overall channel management through the established COT framework, thus improving efficiency without proportionally increasing complexity.
3Reliability
If continuous medium-sensing procedures are performed, then hidden node problems can be detected, but the likelihood of communication interruptions increases
Solution Approach 1:
The patent applies preliminary action by performing comprehensive medium-sensing at the COT initiation stage before any transmissions begin. This preliminary LBT procedure ensures that hidden node interference is detected before communication starts, and once the COT is established, continuous sensing is avoided to maintain communication stability and prevent interruptions.
Solution Approach 2:
The patent maintains communication continuity by eliminating repeated medium-sensing interruptions during the COT period. Once the channel is acquired through preliminary sensing, transmissions proceed continuously through multiple downlink and uplink slots without interruption, ensuring stable communication while the initial sensing has already accounted for potential hidden node interference.
Data Source
AI summary
New radio (NR) unlicensed (NR-U) operations are discussed with channel occupancy time (COT) multiple downlink-uplink switching opportunities supported by an active channel indication. A network node that initiates a COT for transmissions may identify a within-channel occupancy time (COT) scheduled downlink-uplink switching configuration. After beginning transmissions on the COT, the node receives an active channel indication from one or more additional network nodes. In response to the active channel indication, the node may then perform communications with the node from which the active channel indication is received according to the within-COT scheduled downlink-uplink switching configuration for the current COT on a shared communication channel.