Combined SRS-DMRS Pilot Structure for Uplink CSI Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The proliferation of massive machine-type communications (mMTC) in massive multiple-input multiple-output (mMIMO) networks introduces challenges in spectral efficiency and pilot signal orthogonality due to pilot contamination, which compromises channel estimation quality and overall system performance.
Innovation Solution
A joint design of sounding reference signal (SRS) and demodulation reference signal (DMRS) pilots is implemented, creating an orthonormal combined signal structure through concatenation, enhancing orthogonality and increasing system dimensionality to accommodate a larger number of user equipment (UEs) while mitigating pilot contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If separate SRS and DMRS pilot sequences are used independently, then each signal maintains its original orthogonality, but the total number of orthogonal sequences is limited and pilot contamination occurs in mMTC networks
Solution Approach 1:
The patent combines SRS and DMRS pilot sequences into a unified set of orthogonal sequences by concatenating SRS pilot vectors with DMRS pilot vectors. This merging creates a combined pilot sequence structure where both SRS and DMRS contribute to the same orthogonal basis, effectively doubling the number of available orthogonal sequences and eliminating pilot contamination that occurs when separate sequences are used independently in mMTC networks.
Solution Approach 2:
The patent extends the pilot sequence dimensionality by creating a combined space that incorporates both SRS and DMRS sequences. By forming a unified orthogonal basis that includes both sequence types, the system moves from a two-dimensional separate sequence space to a higher-dimensional combined space, enabling support for more UEs without increasing pilot contamination.
2Productivity
If the number of UEs is increased to support mMTC, then network capacity increases, but pilot contamination worsens and channel estimation accuracy decreases
Solution Approach 1:
By merging SRS and DMRS into a unified orthogonal sequence set, the system can accommodate a larger number of UEs simultaneously. The combined pilot sequences provide sufficient orthogonality to distinguish between more users, thereby increasing network capacity while maintaining channel estimation accuracy through the preserved orthogonality of the combined sequence space.
Solution Approach 2:
The patent changes the parameter of sequence orthogonality by creating a combined orthogonal basis that includes both SRS and DMRS sequences. This parameter change enables the system to support more UEs with the same level of orthogonality, effectively increasing network capacity without sacrificing channel estimation accuracy that would otherwise degrade with higher UE density.
3Quantity of substance
If more pilot sequences are allocated to support more UEs, then UE capacity increases, but spectral efficiency decreases due to increased overhead
Solution Approach 1:
The patent merges SRS and DMRS pilot sequences into a unified set, which efficiently utilizes spectral resources. Instead of allocating separate dedicated sequences for each function, the combined approach shares the orthogonal basis between SRS and DMRS, reducing the total overhead while supporting more UEs and thereby improving spectral efficiency.
Solution Approach 2:
The combined pilot sequence structure serves multiple functions simultaneously - it provides both SRS and DMRS functionality within a single orthogonal basis. This multi-functionality allows the system to support more UEs without proportionally increasing the spectral overhead, as the same sequence resources serve dual purposes for channel sounding and data demodulation.
Data Source
AI summary
A method facilitating efficient resource grants for radio resource control (RRC) messaging includes generating, by centralized unit equipment including at least one processor, scheduling instructions for an RRC message, including embedding a resource grant request, for uplink communication resources to be allocated for an uplink message to be transmitted by a user equipment in response to the RRC message, into the scheduling instructions; generating, by the centralized unit equipment, a downlink F1 application protocol (F1AP) message including the RRC message and the scheduling instructions; and transmitting, by the centralized unit equipment, the downlink F1AP message to distributed unit equipment serving the user equipment.