Uplink Random Access Control for π/2-BPSK PUSCH Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Uplink transmission in future radio communication systems employing π/2-Binary Phase Shift Keying (BPSK) modulation for low peak-to-average power ratio (PAPR) is not adequately improved when coexisting with uplink transmissions not using π/2-BPSK modulation.
Innovation Solution
A user terminal and radio communication method that supports π/2-BPSK modulation through enhanced DMRS configurations, including type 1 and type 2 DMRS types, with π/2-BPSK modulation for DMRS sequences in CP-OFDM and DFT-S-OFDM, and dynamic selection of DMRS sequences using RRC and DCI signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If π/2-BPSK modulation is employed for uplink transmission, then PAPR is reduced, but performance improvement is insufficient when coexisting with non-π/2-BPSK transmissions
Solution Approach 1:
The patent applies different modulation schemes (π/2-BPSK for low PAPR, other modulations for performance) to different transmission scenarios and user terminals. The base station dynamically selects which terminals use π/2-BPSK modulation based on channel conditions, terminal capabilities, and traffic requirements, allowing local optimization of PAPR reduction without compromising overall system performance.
Solution Approach 2:
The patent introduces dynamic selection mechanisms where the base station determines, via RRC signaling and DCI, whether each terminal should use π/2-BPSK modulation for PUSCH/PUCCH transmissions. This dynamic approach allows the system to adapt to varying channel conditions and traffic patterns, switching between π/2-BPSK and other modulation schemes as needed to balance PAPR reduction with performance requirements.
2Loss of energy
If π/2-BPSK modulation is applied to all uplink transmissions, then PAPR reduction is maximized, but adaptability to different transmission requirements is reduced
Solution Approach 1:
The patent designs a universal modulation selection framework that supports both π/2-BPSK and other modulation schemes within the same system. The base station can universally apply different modulation schemes to different terminals or transmissions based on requirements, making the system multi-functional in handling diverse transmission scenarios while maintaining the option for PAPR reduction where applicable.
Solution Approach 2:
The patent changes the modulation parameter dynamically based on transmission requirements. The base station configures terminals to use π/2-BPSK modulation (changing the modulation parameter from QPSK or other schemes) when PAPR reduction is prioritized, and reverts to other modulation schemes when performance or adaptability is more important, thus adapting parameters to match different operational requirements.
3Reliability
If DMRS sequence is enhanced with π/2-BPSK modulation, then uplink channel quality is improved, but system complexity increases
Solution Approach 1:
The patent extracts the π/2-BPSK modulation enhancement specifically for the DMRS sequence, separating it from the data transmission modulation. This allows the DMRS to be independently optimized with π/2-BPSK for better channel estimation quality without requiring the entire transmission system to be restructured, thereby limiting the complexity increase to only the reference signal generation and processing parts.
Solution Approach 2:
The patent applies π/2-BPSK modulation to the DMRS sequence in advance before the actual data transmission. The enhanced DMRS with low PAPR properties is generated and transmitted first to establish reliable channel estimation, which then facilitates more accurate reception and demodulation of subsequent data transmissions, improving overall uplink channel quality without adding complexity to the data processing chain.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A user terminal according to one aspect of the present disclosure includes a control section that makes a determination, based on at least one of a resource of a random access preamble, a random access response, and a priority level of a modulation scheme, about whether or not to apply π/2-BPSK modulation for an uplink shared channel scheduled by the random access response, and a transmitting section that transmits the uplink shared channel, based on the determination. According to an aspect of the present disclosure, it is possible to appropriately perform uplink transmission employing π/2-BPSK modulation.