RF Retuning for Msg3 Frequency Hopping in Redcap UEs
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Solution Overview
Problem
In mobile communications, Reduced Capability User Equipment (redcap UE) faces issues where the initial UpLink Bandwidth Part (UL BWP) exceeds its system bandwidth, leading to difficulties in transmitting message 3 (msg3) during the random access procedure, particularly when frequency hopping is enabled, as the frequency domain position of the second hop may exceed the UE's system bandwidth.
Innovation Solution
A method and apparatus for radio frequency retuning are introduced, where a target symbol is determined between the first and second hops for msg3 transmission, allowing the UE to perform RF retuning and align its RF chain to the frequency band, ensuring successful transmission of msg3 via the second hop without exceeding its system bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a larger initial UL BWP is configured to accommodate normal UE, then normal UE can operate properly, but redcap UE cannot transmit msg3 successfully when frequency hopping is enabled
Solution Approach 1:
The patent applies preliminary action by performing RF retuning before the second hop transmission of msg3. The UE determines a target symbol for RF retuning located between the first and second hops, and performs the retuning operation in advance to align the RF chain to the frequency band of the second hop, ensuring successful transmission without exceeding the UE's system bandwidth
Solution Approach 2:
The patent introduces an intermediary mechanism by using a target symbol for RF retuning that acts as a bridge between the first hop and second hop. This target symbol serves as an intermediate resource element that enables the UE to switch frequency bands during msg3 transmission, allowing the UE to operate within its system bandwidth while supporting frequency hopping
2Reliability
If frequency hopping is enabled for msg3 transmission, then transmission diversity is improved, but the second hop frequency may exceed redcap UE system bandwidth
Solution Approach 1:
The patent applies preliminary action by determining and performing RF retuning on a target symbol before the second hop transmission. This preliminary retuning operation aligns the RF chain to the correct frequency band in advance, ensuring that the UE can successfully transmit on the second hop frequency without exceeding its system bandwidth
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the RF chain frequency based on the target symbol for RF retuning. The UE changes its operating frequency parameter from the first hop frequency to the second hop frequency through the intermediate retuning operation, enabling flexible frequency hopping while maintaining compliance with system bandwidth constraints
Data Source
AI summary
A radio-frequency retuning method and apparatus. The method comprises: determining at least one target symbol for radio-frequency retuning (RF retuning), wherein the at least one target symbol is located between a starting symbol of a first hop of msg3 and an ending symbol of a second hop thereof, and performing RF retuning processing on the target symbol.