UE-Initiated COT for Multi-Channel UL in Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication technologies in unlicensed spectrum, such as LTE-LAA and NR-U, face inefficiencies in uplink transmissions due to the restriction that only base stations can initiate channel occupancy times (COTs), leading to unnecessary delays and battery power waste for user equipment (UE) when no data transmission is required.
Innovation Solution
The method allows user equipment (UE) to initiate COTs when the channel is available, aligning uplink transmissions with the starting boundary of a fixed period frame, and transmitting during a UE-initiated COT, which starts at the beginning of the frame and ends before the idle period, enabling UE-initiated COTs over multiple channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only base stations can initiate COTs, then channel access control is simplified, but uplink transmission delays increase and battery power is wasted
Solution Approach 1:
The patent introduces dynamic COT initiation rights where UEs can switch from passive mode (waiting for gNB to initiate COT) to active mode (UE initiating COT) based on channel conditions and transmission needs. This dynamic allocation of COT initiation rights resolves the contradiction by allowing flexible access without complicating the overall control mechanism.
Solution Approach 2:
The patent changes the parameter of COT initiation authority from being exclusively held by gNB to being shareable with UEs under specific conditions. This parameter change enables UEs to initiate COTs when they have data to transmit, reducing delays while maintaining gNB's ultimate control for coordination.
2Device complexity
If only base stations can initiate COTs, then channel access is centralized, but uplink transmission efficiency decreases
Solution Approach 1:
The system dynamically assigns COT initiation rights based on real-time conditions. When a UE has data to transmit and the channel is available, it can initiate a COT, improving transmission efficiency. The gNB retains the ability to initiate COTs when needed for coordinated access, maintaining centralized control where beneficial.
Solution Approach 2:
UEs are enabled to self-initiate COTs when they have data to transmit, eliminating the need to wait for gNB initiation. This self-service capability improves uplink transmission efficiency by allowing UEs to seize available channel opportunities independently.
3Reliability
If UE waits for gNB to initiate COT, then channel access coordination is improved, but transmission latency increases
Solution Approach 1:
The patent implements a dynamic model where UEs can autonomously initiate COTs when conditions are favorable, rather than passively waiting for gNB initiation. This dynamic approach reduces transmission latency while maintaining coordination through gNB's ability to manage multiple COTs and ensure proper channel access protocols are followed.
Solution Approach 2:
UEs perform preliminary channel sensing and preparation before initiating a COT. By assessing channel availability and preparing transmission parameters in advance, UEs can quickly initiate COTs with minimal latency while ensuring proper coordination with the gNB and other devices.
Data Source
AI summary
A user equipment (UE) may be configured/scheduled with uplink (UL) transmissions over multiple channels. Each UL transmission is aligned with a boundary of a UE fixed period frame (FFP). For each UL transmission, the UE may determine whether a gNB has initiated a channel occupancy time (COT) in a gNB FFP over a corresponding channel. If the COT is not initiated, the UE may initiate a COT in the UE FFP over the channel when the channel is available, by transmitting a corresponding UL transmission over the channel in the UE FFP. The UE may send, to the gNB, information indicating UE-initiated COT channel(s) of the multiple channels over which COT(s) have been initiated by the UE. The gNB may provide feedback for the UL transmissions based on the information.