Autonomous Downlink Transmission for 5G NR-U Spectrum Efficiency
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Solution Overview
Problem
In wireless communication systems, especially in 5G NR-U technologies, there is a need to improve the utilization of shared radio spectrum when there is pending downlink data to be transmitted to a UE during an available uplink transmission opportunity, despite the UE having no uplink data to transmit, due to interference and inefficient resource allocation.
Innovation Solution
Enabling an autonomous downlink (ADL) transmission capability in base stations and UEs, which involves initiating a listen-before-talk (LBT) procedure to obtain a transmission opportunity for pending downlink traffic without waiting for an acknowledgement, allowing opportunistic downlink data transmission using available uplink resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE waits for uplink transmission opportunity to receive downlink data, then the downlink transmission reliability is improved, but the spectrum utilization efficiency deteriorates due to idle uplink resources
Solution Approach 1:
The patent inverts the traditional communication direction by enabling the UE to autonomously initiate downlink data reception during uplink transmission opportunities. Instead of waiting for downlink scheduling, the UE sends an autonomous downlink indication and receives downlink data without traditional downlink scheduling, effectively using uplink resources for downlink transmission and resolving the contradiction between reliability and spectrum efficiency.
Solution Approach 2:
The UE performs self-service by autonomously determining when to receive downlink data during uplink opportunities, sending autonomous downlink indications, and managing the reception process without traditional downlink scheduling from the network side, thereby improving spectrum utilization while maintaining reliable transmission.
2Object-affected harmful factors
If the UE initiates LBT procedure to obtain transmission opportunity, then the interference management is improved, but the access complexity deteriorates
Solution Approach 1:
The patent applies LBT procedure universally for both uplink and autonomous downlink transmissions. The same LBT mechanism used for uplink access is also employed for autonomous downlink indication and data reception, simplifying the access process by using an existing multi-functional procedure rather than creating a separate complex access mechanism.
3Adaptability or versatility
If the network uses traditional downlink scheduling, then the resource allocation control is improved, but the transmission latency deteriorates due to waiting for scheduling signals
Solution Approach 1:
The UE performs preliminary action by sending an autonomous downlink indication before receiving downlink data during uplink opportunities. This preliminary indication allows the network to prepare and transmit downlink data without waiting for traditional scheduling signals, reducing transmission latency while the network maintains control through the indication mechanism.
Solution Approach 2:
The patent introduces dynamic autonomous downlink transmission that adapts to real-time channel conditions and traffic requirements. The UE can dynamically initiate downlink reception during uplink opportunities based on LBT results and data availability, providing flexible resource allocation that reduces latency compared to static traditional scheduling.
Data Source
AI summary
A method, apparatus, and computer-readable medium that enable and disable autonomous downlink transmission (ADT) capability at a user equipment (UE) or a gNB are disclosed. The ADT capability is enabled when a triggering event occurs. The ADT capability is realized in part via initiating a listen before talk (LBT) procedure of a first LBT type to obtain an uplink (UL) transmission opportunity (TxOP) after determining that the UE does not have any UL data to transmit, transmitting uplink control information (UCI) with a limited amount of data to request for a resource grant of the TxOP for pending DL data; and receiving the pending DL data, wherein resources for receiving the pending DL data is dynamically configured via the UCI or semi-statically configured through a radio resource control (RRC) protocol message.