FD-MIMO Uplink DMRS Enhancement via IFDMA and OCC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless cellular communication systems, particularly in 3GPP LTE and 5G networks, face challenges in supporting orthogonal Demodulation Reference Signals (DMRS) for Multi-User Multiple-Input Multiple-Output (MU-MIMO) operations with partially overlapping bandwidth allocations, which affects channel estimation and signal processing efficiency.
Innovation Solution
The implementation of Interleaved Frequency Division Multiplex Access (IFDMA) with a Repetition Factor (RPF) of two or four, along with orthogonal Cover Codes (OCCs and cyclic shifts, to generate orthogonal DMRS sequences for overlapping and non-overlapping Resource Blocks (RBs), enabling flexible and efficient DMRS transmission in Full-Dimension Multiple-Input Multiple-Output (FD-MIMO) systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional DMRS sequences are used in MU-MIMO operations with partially overlapping bandwidth allocations, then system compatibility is maintained, but channel estimation performance deteriorates and signal processing efficiency decreases
Solution Approach 1:
The patent segments the DMRS sequence generation process into distinct components: base sequence selection, cyclic shift application, and orthogonal cover code multiplication. This segmentation allows each component to be optimized independently, improving channel estimation performance while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces orthogonal cover codes as an additional dimension for creating orthogonal DMRS sequences. By multiplying base sequences with orthogonal cover codes, the system generates orthogonal sequences without increasing bandwidth or time resources, thereby improving channel estimation accuracy for multiple users sharing the same resources.
2Measurement precision
If orthogonal DMRS sequences are generated for multiple users with overlapping bandwidth allocations, then channel estimation accuracy improves, but the number of required sequences increases system complexity
Solution Approach 1:
The patent changes parameters of existing base sequences by applying different cyclic shifts and orthogonal cover codes. This parameter transformation approach generates multiple orthogonal sequences from a limited set of base sequences, improving channel estimation accuracy for multiple users without proportionally increasing the fundamental sequence inventory.
Solution Approach 2:
The patent makes a limited set of base sequences serve multiple functions by using them with different cyclic shifts and orthogonal cover codes. Each base sequence can generate multiple orthogonal variants, allowing the system to support multiple users with overlapping bandwidth allocations while reusing the same underlying sequence structures.
3Productivity
If DMRS sequences are designed to support partial overlapping resource block allocations, then MU-MIMO efficiency improves, but sequence generation and management becomes more complex
Solution Approach 1:
The patent implements dynamic DMRS sequence generation where the specific sequence used by each user is determined by configurable parameters such as cyclic shift values and orthogonal cover code selections. This dynamic approach allows flexible adaptation to different MU-MIMO scenarios with partial overlapping resource blocks, improving efficiency while keeping the generation mechanism systematic and manageable through parameter control.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Described is an apparatus of an Evolved Node-B (eNB) operable to communicate with a User Equipment (UE) on a wireless network. The apparatus may comprise a first circuitry, a second circuitry, and a third circuitry. The first circuitry may be operable to identify a range of Resource Blocks (RBs). The second circuitry may be operable to process a transmission carrying one or more RB indicators for the range of RBs. The third circuitry may be operable to determine, based on the one or more RB indicators, one or more overlapping sub-ranges of RBs of the range of RBs, and one or more non-overlapping sub-ranges of RBs of the range of RBs.