Single-Transmitter Antenna Selection for FDD Uplink Switching
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Solution Overview
Problem
Existing 5G wireless communication standards lack mechanisms for closed-loop antenna selection in single transmitter wireless devices operating in frequency division duplexing (FDD) configurations, limiting performance and flexibility in uplink transmissions.
Innovation Solution
Configuring multiple SRS resources with codebook usage designation for FDD bands, allowing closed-loop antenna selection by providing SRS indicator (SRI) values, and using open-loop selection for out-of-sync transmissions, along with adaptive power control based on downlink path loss measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop antenna selection is implemented for FDD configurations, then antenna selection accuracy is improved, but device complexity increases due to additional signaling and configuration requirements
Solution Approach 1:
The patent implements closed-loop antenna selection by having the network device measure uplink channel quality based on SRS resources and provide feedback through SRI indicators to the terminal device. This feedback mechanism enables the network to select the optimal antenna port for uplink transmission, improving antenna selection accuracy while managing system complexity through standardized feedback procedures.
Solution Approach 2:
The patent introduces SRS (Sounding Reference Signal) resources as an intermediary mechanism to enable channel measurement and antenna selection. The SRS resources serve as a mediator that allows the network device to assess uplink channel quality for different antenna ports without requiring direct complex interaction between the terminal and network for each antenna selection decision.
2Productivity
If multiple SRS resources are configured for antenna switching, then UL transmission performance is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the uplink channel sounding process into multiple SRS resources, each associated with different antenna ports. This segmentation allows the terminal to transmit sounding signals through different antennas sequentially, enabling the network to measure and select the best antenna port for UL transmission, thereby improving UL performance while managing signaling overhead through efficient resource allocation.
Solution Approach 2:
The patent implements dynamic antenna switching by configuring multiple SRS resources that can be activated based on channel conditions and transmission requirements. The system dynamically selects which SRS resources to use and which antenna ports to activate, allowing flexible adaptation to changing channel conditions while optimizing the balance between UL performance and signaling overhead.
3Adaptability or versatility
If antenna switching is performed between OFDM symbols, then transmission flexibility is improved, but timing synchronization becomes more difficult
Solution Approach 1:
The patent applies preliminary action by configuring the terminal with multiple SRS resources and antenna port information in advance, before actual uplink transmission occurs. The network device provides SRI indicators that pre-indicate which antenna port should be used for upcoming PUSCH or PUCCH transmissions, allowing the terminal to prepare and switch antennas in advance, thereby improving transmission flexibility while maintaining timing synchronization.
Data Source
AI summary
This application describes mechanisms to manage closed-loop antenna selection for a wireless device. The wireless device transmits sounding reference signal (SRS) resources configured by a cellular wireless network in an SRS resource set and receive SRS indicator (SRI) values to indicate antennas for subsequent uplink transmission of one or more physical layer channels by the wireless device, including a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH). The wireless device supplements the closed-loop antenna selection with an open-loop antenna selection and uses the open-loop antenna selection for non-PUSCH channels when a most recently SRI value can be considered stale. SRI-based closed-loop antenna selection is extended to frequency division duplexing (FDD) bands. Transmit precoding matrix indicator (TPMI) group values are also used to indicate differential transmit power capabilities of various antennas of the wireless device to the cellular wireless network.