User Terminal SRS Switching for TDD Throughput

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Solution Overview

Problem

In future radio communication systems like 5G, the temporary frequency switching technique used in TDD can lead to long frequency switching times, causing waveform disturbances and affecting signal quality and subframe configuration, which can result in insufficient throughput.

Innovation Solution

The specification of SRS switching operations by the user terminal, including cases where SRS switching occurs between UL and UL, UL and DL, and DL and DL, allows for efficient frequency switching without concurrent transmission, thereby minimizing waveform disturbances and maintaining signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If temporary frequency switching technique is used in TDD, then uplink transmission can be performed on other carriers when CCs are non-reciprocal, but frequency switching time becomes long causing waveform disturbances and signal quality degradation

Engineering Contradiction:
Improvecarrier switching capabilityVSAvoidsignal quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The user terminal performs frequency switching preparation in advance by switching the frequency before the actual carrier switching occurs. This preliminary frequency switching ensures that when carrier switching is needed, the terminal is already tuned to the correct frequency, eliminating waveform disturbances and signal quality degradation during the switching process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent accelerates the frequency switching process by performing it preliminarily and efficiently, thereby skipping the problematic phase where long switching times cause waveform disturbances. The frequency switching is completed rapidly before the carrier switching trigger, avoiding the harmful effects of prolonged switching.

Inventive Principle:
Principle #21Skipping (Rushing through)

2Adaptability or versatility

If temporary frequency switching technique is used in TDD, then uplink transmission can be performed on other carriers, but throughput becomes insufficient due to waveform disturbances and subframe configuration issues

Engineering Contradiction:
Improvecarrier switching capabilityVSAvoidthroughput
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

By performing frequency switching preliminarily before carrier switching is triggered, the system ensures that throughput is not degraded. The terminal is already at the correct frequency when data transmission begins, avoiding waveform disturbances that would otherwise reduce throughput and cause subframe configuration issues.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3457729B1User terminal, wireless base station, and wireless communication method
Publication Date: 2024.02.21 NTT DOCOMO INC
  • EP3457729B1 patent drawingFigure 1
  • EP3457729B1 patent drawingFigure 2
  • EP3457729B1 patent drawingFigure 3

AI summary

Even when a temporary frequency switching technique is used by TDD, a sufficient throughput is achieved. A user terminal includes: a transmission/reception section that performs uplink transmission and/or downlink reception via a first cell; and a control section that controls the transmission/reception section to transmit capability information related to UL reference signal switching for switching the first cell to a second cell different from the first cell and transmitting a UL reference signal.