Radio Node HARQ-ACK Multiplexing in Unlicensed Bands
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently handling acknowledgement signalling, particularly in unlicensed frequency bands where interference and resource availability issues lead to delayed or missed HARQ-ACK transmissions, impacting low latency and high reliability requirements for URLLC services.
Innovation Solution
The method involves a radio node and network node system that determines whether to multiplex acknowledgement messages using different acknowledgement schemes, allocating resources based on the schemes to ensure timely transmission, even in unlicensed bands, by employing various HARQ codebooks and priority indicators to manage resource allocation and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HARQ-ACK transmissions are performed in unlicensed frequency bands, then coverage area and service versatility are improved, but interference and resource availability issues cause delayed or missed transmissions
Solution Approach 1:
The system dynamically selects between different acknowledgement schemes (first scheme for reliable delivery, second scheme for resource efficiency) based on current channel conditions and transmission requirements. This dynamic adaptation allows the system to optimize between reliability and resource utilization in real-time, resolving the contradiction between service versatility and transmission reliability in unlicensed bands.
Solution Approach 2:
The patent changes the parameter of acknowledgement scheme selection based on transmission conditions. By switching between different HARQ-ACK codebook types (e.g., Type-1, Type-2, Type-3) and different transmission resources (PUCCH, PUSCH) depending on channel state, interference levels, and traffic patterns, the system adapts to unlicensed band conditions while maintaining reliable acknowledgement delivery.
2Reliability
If multiple acknowledgement messages are transmitted separately, then transmission reliability is improved, but transmission latency increases
Solution Approach 1:
The patent merges multiple HARQ-ACK messages into a single multiplexed transmission when channel conditions permit. By combining acknowledgements for multiple downlink transmissions into one uplink message (using appropriate codebook structures), the system reduces the number of separate transmissions required, thereby lowering latency while maintaining reliability through the robustness of the codebook-based approach.
Solution Approach 2:
The system performs preliminary determination of whether to multiplex acknowledgements based on pre-configured rules and current channel assessment. By deciding in advance whether to combine or separate transmissions, the system avoids unnecessary delays while ensuring that reliability requirements are met through appropriate scheme selection before transmission occurs.
3Speed
If resource allocation is optimized for low latency, then transmission speed is improved, but resource availability and interference management become more challenging
Solution Approach 1:
The patent segments resource allocation into different types corresponding to different HARQ-ACK codebook types. By dividing resources into Type-1, Type-2, and Type-3 allocations with specific characteristics (e.g., semi-static vs. dynamic, different PUCCH resource associations), the system optimizes for specific service requirements while managing complexity through structured categorization of resource types.
Solution Approach 2:
The system creates a universal resource allocation framework that can accommodate multiple HARQ-ACK codebook types and transmission schemes through a unified determination process. The same resource allocation mechanism handles both low-latency optimized allocations and reliability-optimized allocations, reducing overall system complexity while maintaining flexibility for different service requirements.
Data Source
AI summary
A method for acknowledging transmissions in a telecommunications network comprising a network node arranged to communicate with a mobile device via a wireless interface. The method comprises the radio node: receiving a first transmission associated with a first acknowledgement scheme; determining that the radio node is unable to transmit a first acknowledgement message for the first transmission; receiving a second transmission from the network node, the second transmission being associated with a second acknowledgement scheme, wherein the second acknowledgement scheme is different from the first acknowledgement scheme; determining acknowledgement resources associated with the second transmission and for the transmission of a second acknowledgement message for the second transmission; deciding, based on the first and second acknowledgement schemes, whether to multiplex the first and second acknowledgement messages; and if it is decided to multiplex the first and second acknowledgement messages, transmitting the first and second acknowledgement messages using the acknowledgement resources.