DMRS Frequency Hopping for CPE CFO Estimation
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Solution Overview
Problem
Current wireless communication systems face challenges in generating and transmitting Demodulation Reference Signals (DMRS) effectively, particularly in addressing Common Phase Error (CPE) and Carrier Frequency Offset (CFO) due to the Doppler Effect, and in enhancing transmission/reception performance through frequency hopping, while also supporting multi-user multiple-input multiple-output (MU-MIMO) operations.
Innovation Solution
A method and device for generating and transmitting DMRS that estimates CPE and CFO values using frequency hopping to enhance data transmission/reception performance, allowing for MU-MIMO operations by mapping DMRS to the same or different locations and configuring DMRS patterns for UEs to perform MU-MIMO operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DMRS is transmitted using frequency hopping, then transmission/reception performance is enhanced by frequency diversity effect, but device complexity increases due to additional positioning and configuration requirements
Solution Approach 1:
The DMRS position is made dynamic through frequency hopping, where the DMRS location changes across different frequency hops. The patent specifies that DMRS is positioned at the first symbol of each hopped hop, allowing the system to adapt to frequency-selective fading conditions while maintaining a systematic approach to DMRS placement that manages complexity.
Solution Approach 2:
The patent introduces configurable parameters for DMRS transmission including frequency hop size, DMRS position within hops, and cyclic shift values. These parameters can be adjusted to optimize performance for different channel conditions and traffic types, allowing the system to balance between exploiting frequency diversity and managing implementation complexity.
2Productivity
If DMRS is mapped to the same location for MU-MIMO operations, then resource utilization is improved, but measurement precision deteriorates due to interference between users
Solution Approach 1:
The patent applies local quality by allowing different DMRS configurations for different users in MU-MIMO scenarios. While DMRS can be mapped to the same time-frequency resources for resource efficiency, each user's DMRS is orthogonalized through different cyclic shift values or orthogonal cover codes, ensuring that each user experiences minimal interference for channel estimation.
Solution Approach 2:
The system performs preliminary orthogonalization of DMRS sequences for different users through cyclic shift and orthogonal cover code assignment before actual data transmission. This preliminary differentiation ensures that even when DMRS are mapped to the same location, users can accurately estimate their respective channels without mutual interference.
3Speed
If DMRS position is fixed at first symbol for frequency hopping, then decoding speed is enhanced, but adaptability worsens for different channel conditions
Solution Approach 1:
The patent implements a dynamic DMRS positioning strategy where the DMRS is placed at the first symbol of each frequency hop to enable rapid decoding. This systematic positioning provides adaptability through frequency diversity, as each hop experiences different channel conditions, allowing the receiver to select the most reliable DMRS instances for decoding while maintaining speed efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution enables accurate decoding of data by estimating CPE and CFO values, enhances transmission/reception performance through frequency diversity, and facilitates MU-MIMO operations by optimizing DMRS positioning and configuration, thereby improving overall system performance.
Implementation Method 1
estimating Common Phase Error (CPE) and Carrier Frequency Offset (CFO) values due to a Doppler Effect
Implementation Method 2
transmitting a DMRS through frequency hopping in order to enhance transmission/reception performance of data by using a frequency diversity effect
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The present disclosure relates to a method and a device for a terminal transmitting a reference signal in a wireless communication system. According to the present disclosure, a method and a device may be provided, the method comprising: receiving, from a base station, configuration information associated with a configuration of a first demodulation reference signal for demodulating uplink data; and on the basis of the configuration information, transmitting the first demodulation reference signal and the uplink data to the base station via at least one antenna port, wherein the first demodulation reference signal and the uplink data are transmitted in a sub frame by means of frequency hopping, and the first demodulation reference signal is positioned on the same time axial symbol as that of at least one other demodulation reference signal transmitted on another antenna port.