HD-FDD HARQ Timing Reference Segmentation for Throughput
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Solution Overview
Problem
Half-duplex frequency division duplex (HD-FDD) devices face reduced throughput due to their inability to perform simultaneous uplink and downlink transmissions, resulting in inefficient use of subframes and limited frequency resources, especially when HARQ ACK/NACK timing follows legacy FDD timing, limiting the availability and efficiency of time resources.
Innovation Solution
A method and apparatus that determine and transmit separate timing references for HARQ operations in HD-FDD systems, allowing for flexible HARQ timing configurations that enable multiple ACK/NACK transmissions in the same subframe and optimize UL/DL data transmission, using predetermined timing references for both downlink and uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If legacy FDD HARQ ACK/NACK timing is used in HD-FDD systems, then the timing reference is simple and follows existing standards, but the system throughput is significantly reduced because ACK/NACK transmissions occupy subframes that cannot be used for data transmission
Solution Approach 1:
The patent segments the HARQ timing reference into separate references for uplink and downlink transmissions. The network determines a first timing reference for DL HARQ and a second timing reference for UL HARQ independently, allowing flexible allocation of subframes for data transmission versus ACK/NACK transmission, thereby increasing system throughput without sacrificing subframe availability.
Solution Approach 2:
The patent introduces dynamic timing reference selection where the network can determine different timing references for UL and DL HARQ operations based on traffic conditions and resource availability. This dynamic approach allows the system to adaptively optimize throughput by flexibly assigning subframes for data transmission while maintaining proper HARQ timing.
2Ease of manufacture
If HD-FDD devices remove duplexers to reduce cost, then device cost is reduced, but the ability to perform simultaneous uplink and downlink transmissions is lost, resulting in inefficient subframe usage
Solution Approach 1:
The patent segments HARQ timing management into separate uplink and downlink timing references, allowing the system to independently optimize each direction's resource usage. This segmentation enables efficient subframe utilization in HD-FDD systems that cannot simultaneously transmit and receive, thereby improving productivity without requiring expensive duplexers.
Solution Approach 2:
The patent changes the timing reference parameters for HARQ operations in HD-FDD systems, allowing flexible adjustment of ACK/NACK timing to maximize subframe utilization. By determining timing references from predetermined sets and transmitting them to UEs, the system optimizes subframe efficiency while maintaining compatibility with HD-FDD hardware constraints.
3Productivity
If separate timing references are determined for UL and DL HARQ operations, then subframe usage flexibility is improved and throughput increases, but the device complexity increases due to additional timing reference management
Solution Approach 1:
The patent segments timing reference management into distinct uplink and downlink components, with the network determining separate timing references for each direction. This segmentation simplifies the overall management by providing clear, independent timing rules for UL and DL HARQ operations, reducing the complexity burden on devices while maintaining high throughput.
Solution Approach 2:
The network acts as an intermediary that determines and transmits the timing references to UEs. This intermediary approach centralizes the complexity of timing reference selection in the network side, where computational resources are more abundant, while keeping device complexity low. The network transmits the determined timing references to UEs, who simply follow the provided timing rules.
Data Source
AI summary
A network of a half-duplex frequency division duplex (HD-FDD) communication system for handling hybrid automatic repeat request (HARQ) includes a processing means for executing a program; and a storage unit, coupled to the processing means, for storing the program. The program instructs the processing means to perform the following steps: determining a first timing reference for a HARQ of downlink (DL) transmission from a first set of predetermined timing references, and determining a second timing reference for a HARQ of uplink (UL) transmission from a second set of predetermined timing references; and transmitting the first timing reference and the second timing reference to a user equipment of the HD-FDD communication system, allowing the user equipment to perform the HARQ of DL transmission based on the first timing reference and perform the HARQ of UL transmission based on the second timing reference.