DSDS UE HARQ Feedback Management During RF Gaps
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Solution Overview
Problem
Dual Sim Dual Standby (DSDS) User Equipment (UE) experiences throughput loss and increased latency due to interruptions in Hybrid Automatic Repeat Request (HARQ) feedback transmission caused by RF usage gaps, leading to unnecessary retransmissions and resource wastage, as the network assumes packet loss during these gaps.
Innovation Solution
The DSDS UE determines whether parameters associated with primary and secondary packet data, including reordering timer value, New Data Indicator (NDI), HARQ process number, and RF gap duration, are identical, and performs HARQ feedback transmission only when the primary packet data is successfully decoded, thereby reducing latency and eliminating duplicate retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RF usage gaps are created for stack-2 activities (paging reception, measurements, signaling), then stack-2 communication is maintained, but HARQ feedback transmission on stack-1 is interrupted causing throughput loss and increased latency
Solution Approach 1:
The UE stores HARQ feedback information in advance before RF gaps occur, and transmits it after the gap using parameters from previously received downlink packets. This preliminary storage and deferred transmission prevents throughput loss while maintaining multi-SIM functionality.
2Adaptability or versatility
If HARQ feedback transmission is interrupted during RF gaps, then stack-2 activities can proceed, but the network performs unnecessary retransmissions wasting wireless resources
Solution Approach 1:
The network is provided with parameters (reordering timer value, NDI, HARQ process number, RF gap duration) that enable it to understand the RF gap situation and adjust its retransmission behavior accordingly, preventing unnecessary retransmissions and wireless resource wastage.
Solution Approach 2:
The UE prepares and stores HARQ feedback information before RF gaps occur, using parameters from previously received downlink packets. This allows the network to be informed in advance about the upcoming gap and adjust its transmission strategy to avoid wasteful retransmissions.
3Reliability
If the network continues to decode HS-DPCCH channel during RF gaps assuming packet loss, then HARQ retransmissions are triggered, but actual packet loss did not occur
Solution Approach 1:
The UE stores HARQ feedback information and relevant parameters (reordering timer, NDI, HARQ process number) before RF gaps occur. After the gap, it transmits this pre-prepared feedback, allowing the network to correctly interpret the acknowledgment status and avoid unnecessary retransmissions, thus reducing packet recovery delay while maintaining reliability.
Data Source
AI summary
A method for managing Hybrid Automatic Repeat Request (HARQ) feedback transmission by a Dual Sim Dual Standby (DSDS) User Equipment (UE) in a wireless communication network, is provided. The method includes determining, by the DSDS UE, whether a first parameter associated with a primary packet data is identical to a second parameter associated with a secondary packet data. Each of the first parameter and the second parameter comprises a reordering timer value, a New Data Indicator (NDI), a HARQ process number, and a DSDS Radio Frequency (RF) gap duration. The method further includes, in response to the first parameter associated with the primary packet data being determined to be identical to the second parameter associated with the secondary packet data and the primary packet data being successfully decoded at the DSDS UE, performing, by the DSDS UE, the HARQ feedback transmission with the wireless communication network.