Uplink MIMO Precoding for Full-Power WTRU Transmission
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Solution Overview
Problem
Existing wireless transmit/receive units (WTRUs) face challenges in achieving full power transmission due to limitations in power amplifier architectures, which hinder effective uplink MIMO transmission.
Innovation Solution
A wireless transmit/receive unit (WTRU) indicates its power rating and coherence capability, overrides codebook subset restrictions, and signals full power transmission capability, allowing it to determine and transmit a subset of precoding matrix indicators (TPMIs) for precoding uplink data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional power amplifier architectures are used in WTRUs, then device complexity is reduced and ease of manufacture is improved, but full power transmission capability is not achieved and MIMO performance is hindered
Solution Approach 1:
The patent segments the power amplifier architecture into multiple parallel PAs (e.g., four PAs for four antenna ports) instead of using a single conventional PA. Each PA can be independently controlled and optimized, allowing the system to achieve full power transmission across multiple antenna ports while maintaining manageable complexity through modular design
Solution Approach 2:
The patent transitions from scalar power control to vector power control by introducing multiple parallel power amplifier paths. This dimensional expansion allows independent power adjustment for each antenna port, enabling full power transmission capability while the network can select appropriate subsets based on channel conditions
2Productivity
If codebook subset restrictions are applied, then device complexity and processing are reduced, but transmission efficiency and MIMO performance are degraded
Solution Approach 1:
The patent implements dynamic codebook subset restriction where the network can adaptively configure which codebook subsets are restricted based on channel conditions, WTRU capability, and traffic requirements. This dynamic approach allows the system to maintain high transmission efficiency when conditions permit while reducing complexity only when necessary
Solution Approach 2:
The patent changes the parameter of codebook subset restriction from a fixed constraint to a configurable parameter that can be adjusted via RRC signaling. The network can modify the restriction configuration to optimize the balance between transmission efficiency and processing complexity based on real-time conditions
3Productivity
If full power transmission capability is implemented, then MIMO performance and transmission efficiency are improved, but device complexity and power amplifier architecture requirements increase
Solution Approach 1:
The patent segments the transmit chain into multiple parallel power amplifier paths, each capable of operating at full power for its designated antenna port. This segmentation enables full power transmission capability while maintaining modular architecture that manages complexity through standardized, repeatable PA units
Solution Approach 2:
The patent designs the power amplifier architecture with universal, interchangeable PA modules that can be configured in different numbers and combinations based on requirements. This multi-functionality allows the same basic PA design to serve multiple antenna ports, reducing overall complexity through standardization
Data Source
AI summary
A WTRU may be configured to transmit to a network (e.g., in a first indication) a full power uplink transmission capability associated with the WTRU, e.g., Cap3. The WTRU may receive (e.g., in a second indication) an indication of whether the WTRU is allowed to operate with full power transmission. The WTRU may determine (e.g., from a set of TPMIs), a subset of TPMIs based on, for example, the WTRU's full power uplink transmission capability (e.g., where the subset of TPMIs includes a first TPMI). The set of TPMIs may comprise one or more subsets of TPMIs. The WTRU may transmit (e.g., in a third indication) an indication of the determined subset of TPMIs. The WTRU may receive (e.g., in a fourth indication) an indication of the first TPMI in the subset of TPMIs. The WTRU may transmit to the network uplink data precoded with the first TPMI.