Single-Transmitter Dual Connectivity HARQ Timing in TDD Cells

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing hybrid automatic repeat request (HARQ) operations for dual connectivity scenarios, particularly when a user equipment (UE) is operating in single transmitter mode, leading to improper scheduling of uplink and downlink subframes, especially in time division duplexing (TDD) configurations.

Innovation Solution

The UE receives system information block (SIB)-configured primary cell (PCell) and secondary cell (SCell) TDD uplink-downlink configurations, compares them with radio resource control (RRC)-configured PCell configurations, and determines usable uplink subframes for HARQ-related transmissions, ensuring proper scheduling even in single transmitter operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a user equipment connects to multiple cell towers simultaneously for dual connectivity, then the data transfer speed and network reliability are improved, but the power consumption increases significantly

Engineering Contradiction:
Improvedata transfer speedVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic transmitter switching where the user equipment alternates between transmitting uplink signals to the first cell tower (master node) and second cell tower (secondary node) based on scheduling decisions. This dynamic time-division approach allows the equipment to maintain dual connectivity benefits while reducing continuous power consumption by activating only one transmitter at a time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic switching between transmitters according to time division multiplexing schedules. The user equipment transmits to the first transmitter during allocated time periods and to the second transmitter during other allocated periods, creating a periodic transmission pattern that reduces overall power consumption compared to continuous simultaneous transmission.

Inventive Principle:
Principle #19Periodic action

2Reliability

If a user equipment uses two transmitters simultaneously for dual connectivity, then the communication reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the functionality of two separate transmitters into a single transceiver that operates in a time-division manner. By merging the transmission functions and controlling them through a unified switching mechanism based on scheduling information, the system maintains communication reliability through dual connectivity while reducing device complexity compared to having two independently operating transmitters.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single transceiver is designed to perform multiple functions by switching between connecting to the first cell tower and the second cell tower. This multi-functional transceiver can serve both connectivity requirements sequentially, eliminating the need for dedicated hardware for each connection and thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3906749B1Single transmitter switching for dual connectivity
Publication Date: 2026.05.06 QUALCOMM INC
  • EP3906749B1 patent drawingFigure 1
  • EP3906749B1 patent drawingFigure 2
  • EP3906749B1 patent drawingFigure 3A

AI summary

Methods, systems, and devices for wireless communications are described. In some cases, a user equipment (UE) may identify, for a carrier aggregation (CA) configuration including a primary cell and one or more secondary cells, a first frame structure configuration for the primary cell and a second frame structure configuration for a secondary cell of the one or more secondary cells. The UE may receive, from a base station, a downlink communication on the secondary cell. The UE may determine a feedback timing for the secondary cell based on the first frame structure configuration for the primary cell and the second frame structure configuration for the secondary cell. The UE may transmit, in response to the received downlink communication, feedback to the base station according to the feedback timing.