DRX Cycle Start Offset Correction for SFN Wraparound
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, the frame number wraparound issue in discontinuous reception (DRX) cycles leads to misalignment in the start of DRX cycles, causing communication delays and resource wastage, particularly for extended reality services that last longer than the SFN range.
Innovation Solution
Adjust the DRX cycle start time by accounting for the number of times the SFN has wrapped around, using modified formulas to determine the drx-StartOffset, ensuring consistent alignment across devices and networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SFN is used as the basis for DRX cycle timing without accounting for wraparound, then the DRX cycle timing is simple to implement, but the DRX cycle alignment becomes incorrect after SFN wraps around causing communication delays
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the number of SFN wraparounds (m) before determining the DRX cycle start time. This counter m is maintained and updated whenever SFN wraps around, allowing the system to compensate for wraparound effects in advance rather than dealing with timing misalignment after it occurs. The formula drx-StartOffset = [(m×10240+SFN×10)+subframe number] mod drx-LongCycle uses this pre-maintained counter to ensure correct timing.
Solution Approach 2:
The patent introduces an intermediary counter m that tracks the number of SFN wraparounds. This counter acts as a mediator between the limited-range SFN (0-1023) and the extended time period required for DRX cycles longer than 10.24 seconds. By adding the term m×10240 to the timing calculation, the system effectively extends the SFN's time coverage without changing the SFN itself, thus maintaining compatibility with existing SFN mechanisms while solving the wraparound problem.
2Ease of operation
If the DRX cycle start time is determined using the standard formula without SFN wraparound correction, then the calculation is straightforward, but the DRX cycle length varies after wraparound causing resource wastage
Solution Approach 1:
The patent changes the parameter used for DRX cycle timing from just SFN to a composite parameter that includes both SFN and the wraparound counter m. The modified formula drx-StartOffset = [(m×10240+SFN×10)+subframe number] mod drx-LongCycle transforms the timing calculation to account for multiple SFN cycles. This parameter change maintains ease of calculation (still a simple modulo operation) while ensuring consistent DRX cycle lengths and preventing resource wastage.
3Adaptability or versatility
If the SFN range (0-1023) is used directly for DRX timing, then the system is compatible with existing 5G specifications, but DRX cycles longer than 10.24 seconds cannot be properly supported
Solution Approach 1:
The patent adds another dimension to the time representation by introducing the wraparound counter m. Instead of trying to extend the SFN range within its existing dimension (0-1023), the system creates a new dimensional layer by counting how many times SFN has wrapped around. This transforms the time representation from a single 10-bit value (SFN) to a two-component system (m, SFN), effectively providing unlimited time duration support while maintaining compatibility with the original SFN specification.
Data Source
AI summary
A first entity in a communications network that includes a second entity can determine a discontinuous reception (“DRX”) cycle start time based on a number of times a frame number (“FN”) has wrapped around. The first entity can further initiate a DRX cycle at the DRX cycle start time.