Half-Duplex Device Data Transmission Scheduling
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Solution Overview
Problem
Half-duplex devices in frequency division duplex (FDD) systems face challenges in simultaneously performing uplink and downlink transmissions due to assumed full-duplex capabilities in 3GPP LTE and LTE-Advanced systems, leading to the need for selecting between transmission and reception, which complicates radio resource scheduling and increases hardware complexity.
Innovation Solution
A data transmission method for half-duplex devices that allows them to transmit uplink data in one subframe and determine whether to receive downlink data or transmit additional uplink data in a subsequent subframe, based on the type of data being exchanged, such as ACK/NACK signals or channel state information, enabling flexible radio resource scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a half-duplex device operates in an FDD system assuming full-duplex capabilities, then the device can achieve simultaneous uplink and downlink transmissions, but the device complexity and hardware cost increase
Solution Approach 1:
The patent implements dynamic scheduling where the base station adaptively assigns uplink and downlink subframes based on the half-duplex device's capability. The scheduling flexibility allows the system to optimize resource allocation dynamically, switching between uplink and downlink modes in different subframes without requiring simultaneous transmission capability, thus maintaining productivity while reducing hardware complexity.
2Device complexity
If a half-duplex device selects between uplink transmission and downlink reception, then the hardware complexity is reduced, but the radio resource scheduling becomes complicated
Solution Approach 1:
The base station acts as an intermediary that manages the scheduling complexity. It receives capability information from the half-duplex device, determines the optimal scheduling configuration, and assigns uplink and downlink subframes accordingly. This centralizes the scheduling decision-making process, simplifying the operation for the half-duplex device while maintaining efficient resource utilization.
Solution Approach 2:
The system changes scheduling parameters dynamically based on device type. When a half-duplex device is detected, the base station modifies the scheduling configuration to avoid simultaneous uplink and downlink assignments, using different time subframes for each direction. This parameter adjustment resolves the scheduling complexity by adapting the resource allocation strategy to the device's operational constraints.
3Device complexity
If a half-duplex device gives up either uplink transmission or downlink reception, then the device can operate with simpler hardware, but the data transmission efficiency decreases
Solution Approach 1:
The base station performs preliminary scheduling actions by pre-determining which subframes will be allocated for uplink and which for downlink based on the half-duplex device's capability. This advance planning ensures that the device can efficiently utilize all available subframes for its intended direction without conflict, maximizing data transmission efficiency while maintaining simple hardware architecture.
Solution Approach 2:
The system implements periodic alternating schedules where uplink and downlink transmissions are assigned in alternating time periods or subframes. This periodic structure allows the half-duplex device to systematically switch between transmission and reception modes, ensuring continuous data flow in both directions over time while maintaining simple hardware that cannot handle simultaneous operations.
Data Source
AI summary
The present invention relates to a data transmission method for a half-duplex device in a wireless communication system. The half-duplex device transmits first uplink data to a base station in an n-th subframe. The half-duplex device determines whether to receive downlink data which is a response to the first uplink data from the base station in an (n+r)-th (where r>1) subframe or to transmit second uplink data to the base station.