Radio Terminal Uplink Resource Allocation for Channel Estimation
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Solution Overview
Problem
Current mobile communication systems face challenges in efficiently estimating downlink channel state information (CSI) due to the asymmetry in uplink and downlink data transmission, where the number of uplink resources allocated is often fewer than downlink resources, making it difficult to accurately feedback acknowledgement/negative acknowledgement (ACK/NACK) signals.
Innovation Solution
The implementation of a radio terminal and base station configuration in a time division duplex system, where the radio terminal uses an uplink radio resource overlapping with a downlink resource block to transmit response information, even if no uplink data transmission is allocated, allowing for efficient channel estimation by utilizing the reversibility of uplink and downlink channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink radio resources are allocated only when uplink data transmission is required, then uplink resource allocation efficiency is improved, but downlink channel state information estimation accuracy deteriorates
Solution Approach 1:
The patent applies multi-functionality by enabling uplink radio resources to serve dual purposes: transmitting uplink data when needed and transmitting response information (ACK/NACK) when uplink data transmission is not allocated. This allows the same resource to fulfill multiple functions, improving overall system efficiency while maintaining accurate channel estimation through consistent response information transmission.
Solution Approach 2:
The patent implements preliminary action by pre-configuring uplink radio resources for response information transmission before actual data transmission occurs. The base station allocates these resources in advance through RRC signaling, ensuring that response information can be transmitted immediately when needed without waiting for dynamic scheduling, thereby maintaining estimation accuracy while improving efficiency.
2Measurement precision
If uplink radio resources are allocated for every downlink transmission, then downlink channel state information estimation accuracy is improved, but uplink resource waste increases
Solution Approach 1:
The patent applies local quality by making response information transmission configurable at the user equipment level rather than applying a uniform allocation strategy to all UEs. The base station can individually configure each UE to transmit response information on uplink data resources when uplink data is not allocated, allowing optimized resource usage tailored to specific traffic conditions and UE requirements.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the transmission behavior of response information based on uplink data allocation status. When uplink data transmission is allocated, response information is transmitted through the PUSCH; when no uplink data allocation is provided, response information is transmitted using pre-configured uplink radio resources. This parameter-based approach optimizes resource usage while maintaining estimation accuracy.
3Reliability
If response information is transmitted using dedicated uplink control channel resources, then transmission reliability is improved, but resource flexibility deteriorates
Solution Approach 1:
The patent applies merging by combining response information transmission with uplink data transmission resources. When uplink data is allocated, response information is multiplexed on the PUSCH alongside data. When no uplink data allocation is provided, response information uses pre-configured uplink radio resources. This merging approach maintains reliability through dedicated resource guarantees while improving flexibility by eliminating separate dedicated control channel requirements.
Data Source
AI summary
A radio terminal according to one embodiment comprises a controller configured to perform radio communication in a time division duplex system, with a base station. The controller is configured to receive a downlink radio signal from the base station; and transmit to the base station, response information indicating whether reception of the downlink radio signal is successful, wherein the response information is transmitted by using an uplink radio resource different from an uplink control channel resource even if the uplink radio resource is not allocated for data transmission from the base station.