Avoiding CRS and DMRS Collisions in Dynamic Spectrum Sharing
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Solution Overview
Problem
Dynamic spectrum sharing (DSS) between 4G and 5G wireless communication systems often results in collisions between cell-specific reference signals (CRS) and demodulation reference signals (DMRS), particularly when a Type-B physical downlink shared channel (PDSCH) is scheduled, leading to failed random access procedures and decoding issues in user equipment (UE).
Innovation Solution
The UE receives cell-specific reference signals (CRS) and demodulation reference signals (DMRS) in a slot via DSS spectrum, with the DMRS associated with a Type-B PDSCH scheduled by downlink control information format 1_0, starting at the fourth symbol and having a duration of ten symbols, ensuring no collision between CRS and DMRS, allowing successful decoding of the PDSCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic spectrum sharing is implemented between 4G and 5G systems, then spectrum utilization efficiency is improved, but signal collision between CRS and DMRS occurs leading to decoding failures
Solution Approach 1:
The patent applies preliminary action by determining the time-frequency resource positions of both CRS and DMRS before actual signal transmission, and adjusting DMRS positions in advance to avoid collision with CRS. The UE determines whether collision will occur based on scheduling information and CRS configuration, and pre-adjusts the DMRS position accordingly to prevent decoding failures.
2Reliability
If DMRS position is adjusted to avoid CRS collision, then signal decoding reliability is improved, but signal position flexibility is reduced
Solution Approach 1:
The patent applies dynamics by making the DMRS position adjustable rather than fixed. When collision with CRS is detected, the DMRS position is dynamically shifted to an adjacent resource element. This dynamic adjustment mechanism maintains decoding reliability while adapting to different spectrum sharing scenarios between 4G and 5G systems.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, in a slot via a dynamic spectrum sharing (DSS) spectrum, a plurality of cell-specific reference signals (CRSs) of a first radio access technology (RAT). The UE may receive, in the slot via the DSS spectrum, a plurality of demodulation reference signals (DMRSs) of a second RAT, wherein the plurality of DMRSs is associated with a Type-B physical downlink shared channel (PDSCH) scheduled by downlink control information format 1_0, wherein the Type-B PDSCH starts at a fourth symbol of the slot and has a duration of ten symbols, and wherein the slot contains no collision between any CRS of the first RAT and any DMRS associated with the Type-B PDSCH. Numerous other aspects are described.