DMRS Positioning for 5G UE Processing Delay Reduction
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Solution Overview
Problem
In 5G communication systems, reducing the Transmission Time Interval (TTI) to 0.5ms or less leads to processing delays for User Equipment (UE) due to the lagging position of De Modulation Reference Signals (DMRS), with existing solutions failing to effectively address this issue.
Innovation Solution
The method involves determining and altering the location of the DMRS within the time-frequency resource in the TTI, allowing it to be sent on symbols with minimal indices, thereby reducing processing delays by advancing its position without conflicting with Cell-specific Reference Signals (CRS) or Physical Downlink Control Channel (PDCCH) zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the Transmission Time Interval (TTI) is reduced to 0.5ms or less, then the processing time and latency are reduced, but the De Modulation Reference Signal (DMRS) lags behind causing major processing delays for User Equipment (UE)
Solution Approach 1:
The patent applies preliminary action by positioning the DMRS at the earliest possible symbol index (n=0 or n=1) within the TTI, allowing the UE to perform channel estimation as early as possible before data reception begins. This advance positioning ensures that channel assessment is completed without delaying the data processing timeline, directly resolving the contradiction between reduced TTI duration and adequate channel estimation timing
2Loss of time
If the DMRS is positioned earlier in the TTI to reduce processing delay, then processing time is reduced, but it may conflict with Cell-specific Reference Signals (CRS) or Physical Downlink Control Channel (PDCCH) zones
Solution Approach 1:
The patent applies local quality by allocating DMRS resources specifically to symbols that do not carry CRS or PDCCH, creating a localized resource allocation strategy. The system identifies symbols with minimal indices that are free from conflicts with other signal types, and positions DMRS only in those specific locations. This selective, localized approach avoids the need for complex global resource coordination while ensuring timely DMRS transmission
Solution Approach 2:
The patent implements dynamics by making the DMRS symbol position adaptable rather than fixed. The system dynamically selects the appropriate symbol index for DMRS based on the actual TTI structure, presence of CRS, and PDCCH configuration. This dynamic positioning allows the DMRS to be placed at the earliest available symbol in each specific scenario, optimizing processing delay reduction while automatically avoiding conflicts with other signals
3Quantity of substance
If DMRS overhead is reduced by not sending DMRS in every short TTI, then resource efficiency improves, but channel estimation accuracy may be compromised
Solution Approach 1:
The patent applies periodic action by implementing a selective DMRS transmission strategy where DMRS is sent in a periodic or patterned manner rather than in every short TTI. The system determines which TTIs require DMRS based on scheduling decisions and channel conditions, creating a periodic transmission pattern that reduces overall overhead while maintaining adequate channel estimation coverage across the communication session
Data Source
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AI summary
The present invention provides a reference signal transmitting method and device, and a reference signal receiving method and device. The transmitting method comprises: determining the position of a time-frequency resource for a reference signal a transmission time interval (TTI) according to a preset manner; and transmitting the reference signal according to the position of the time-frequency resource. The present invention solves the problem in the related art of high processing delay of a user equipment (UE) that occurs because a DMRS is later-positioned, and reduces the processing delay of the UE.