Distinct DMRS Sequence Initial Values for LTE E-PDCCH and PDSCH Interference
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Solution Overview
Problem
In LTE systems, the use of the same DMRS sequence for both E-PDCCH and PDSCH leads to interference and reduced system performance, especially in HetNet scenarios where multiple users share the same DMRS sequence, causing orthogonality issues and affecting system performance.
Innovation Solution
Generating distinct DMRS sequence initial values for E-PDCCH and PDSCH, allowing terminals to acquire and generate separate DMRS sequences for each channel, thereby ensuring different initial values and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same DMRS sequence is used for both E-PDCCH and PDSCH, then the implementation is simple and consistent, but system interference increases and performance deteriorates in HetNet scenarios
Solution Approach 1:
The patent segments the DMRS sequence generation by introducing separate initial value parameters for E-PDCCH (n_SCID_E-PDCCH) and PDSCH (n_SCID_PDSCH). This allows the terminal to generate distinct DMRS sequences for control channel and data channel, thereby avoiding interference while maintaining independent optimization of each channel's performance.
2Productivity
If multiple users share the same DMRS sequence within a cell, then the resource utilization is efficient, but orthogonality is compromised and system performance is adversely affected
Solution Approach 1:
The patent applies local quality by allowing different users to be assigned different n_SCID values (0 or 1) for DMRS sequence generation. This enables fine-grained differentiation of DMRS sequences at the user level, ensuring orthogonality for MU-MIMO users while maintaining efficient resource utilization across the cell.
3Object-affected harmful factors
If distinct DMRS sequences are generated for E-PDCCH and PDSCH, then system interference is reduced and performance is enhanced, but the terminal's processing complexity increases
Solution Approach 1:
The patent changes the parameter n_SCID to differentiate DMRS sequences for E-PDCCH and PDSCH. By modifying this single initial value parameter based on the channel type, the system achieves distinct sequences without requiring fundamentally different generation algorithms, thus limiting the increase in terminal processing complexity.
4Ease of operation
If the DMRS sequence initial values for E-PDCCH and PDSCH are the same, then the configuration is consistent and simple, but orthogonality between ports cannot be ensured in MU-MIMO scenarios
Solution Approach 1:
The patent introduces dynamic configuration of n_SCID values through higher-layer signaling (RRC or MAC CE). This allows the network to flexibly assign different initial values for E-PDCCH and PDSCH based on the specific scenario requirements, achieving both configuration simplicity through standardized procedures and orthogonality assurance through adaptive parameter assignment.
Data Source
Figure 1~2
AI summary
A method for generating DMRS sequences, including: a terminal acquiring a DMRS sequence initial value corresponding to an E-PDCCH and a DMRS sequence initial value corresponding to a PDSCH; and generating a DMRS sequence corresponding to the E-PDCCH using the DMRS sequence initial value corresponding to the E-PDCCH, and a DMRS sequence corresponding to the PDSCH using the DMRS sequence initial value corresponding to the PDSCH. The DMRS sequence initial value corresponding to the E-PDCCH is different from the DMRS sequence initial value corresponding to the PDSCH. Also disclosed are a method for transmitting a DMRS sequence initial value, a corresponding terminal and a base station.