LTE Terminal Configuration Management for Uplink-Downlink Interference
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Solution Overview
Problem
In LTE communication systems, there is a risk of uplink signal interference due to terminal apparatuses erroneously transmitting signals during subframes intended for downlink signals, leading to incorrect decoding of scheduling information.
Innovation Solution
Implementing a configuration management system in both terminal and base station apparatuses to differentiate between subframes for physical downlink control channels, physical uplink shared channels, and HARQ-ACK transmissions, using periodic sounding reference signals to specify valid uplink subframes and manage configurations to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traffic adaptation technique is applied to change uplink/downlink resource ratio, then throughput is improved, but the risk of terminal apparatus erroneously transmitting uplink signals in downlink subframes increases
Solution Approach 1:
The patent applies preliminary action by having the terminal apparatus transmit a periodic sounding reference signal (SRS) in advance to inform the base station of its intended uplink transmission timing. This allows the base station to pre-configure appropriate reception settings and prevent erroneous decoding of scheduling information, thereby maintaining high throughput while reducing transmission errors.
Solution Approach 2:
The patent implements feedback through the periodic sounding reference signal that provides the base station with information about the terminal's uplink transmission intentions. This feedback mechanism enables the base station to adjust its reception configuration accordingly, ensuring accurate decoding of scheduling information and preventing interference between uplink and downlink signals.
2Adaptability or versatility
If flexible subframe is used for dynamic TDD, then traffic adaptation capability is improved, but interference between uplink and downlink signals increases
Solution Approach 1:
The terminal apparatus transmits the periodic sounding reference signal in advance of actual uplink transmission, allowing the base station to pre-configure reception settings for flexible subframes. This preliminary action enables the system to maintain traffic adaptation capability while preventing interference by ensuring the base station is properly prepared for uplink signals before they are transmitted.
Solution Approach 2:
The periodic sounding reference signal acts as an intermediary between the terminal apparatus and base station, providing critical information about intended uplink transmission timing. This intermediary signal allows the base station to distinguish between legitimate uplink transmissions and potential interference, thereby enabling flexible subframe usage without signal conflicts.
3Adaptability or versatility
If HARQ timing is determined based on uplink-downlink configuration, then scheduling flexibility is improved, but the complexity of configuration management increases
Solution Approach 1:
The terminal apparatus autonomously manages its own configuration by transmitting the periodic sounding reference signal based on its internal scheduling decisions. This self-service approach allows the terminal to determine appropriate HARQ timing without requiring complex base station intervention, thereby maintaining scheduling flexibility while reducing overall system configuration management complexity.
Data Source
AI summary
A terminal apparatus includes a configuration unit that sets a first configuration, a second configuration, and a third configuration. The configuration unit specifies an uplink subframe in which transmission of PUSCH is possible according to the second configuration, when the first configuration and the second configuration are set and the third configuration is not set, the first configuration is used to determine a correspondence between a subframe in which PDCCH is arranged and a subframe in which PUSCH corresponding to the PDCCH is arranged, the second configuration is used to determine a correspondence between a subframe in which PDSCH is arranged and a subframe in which a HARQ-ACK corresponding to the PDSCH is transmitted, and the third configuration is used to specify a subframe for which the PDCCH is monitored.