Self-Contained TDD Subframe HARQ-ACK Latency Reduction
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Solution Overview
Problem
In 3GPP LTE systems, longer Hybrid automatic repeat request (HARQ) acknowledgement (HARQ-ACK) transmission latency occurs in Time-Division Duplex (TDD) configurations due to the unavailability of downlink (DL) or uplink (UL) subframes for HARQ-ACK transmission, leading to inefficiencies in mobile communication networks.
Innovation Solution
Implementing a self-contained TDD subframe structure with an advanced physical downlink shared channel (xPDSCH) scheduled by an advanced physical downlink control channel (xPDCCH), and inserting a guard period between xPDSCH and advanced physical uplink control channel (xPUCCH) to accommodate switching time and propagation delay, allowing for HARQ-ACK transmission within a single subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional TDD subframe structure is used, then DL or UL subframe availability is maintained according to conventional configurations, but HARQ-ACK transmission latency increases due to subframe unavailability
Solution Approach 1:
The patent applies dynamics by making the TDD subframe structure flexible and adaptive. The base station dynamically determines whether to transmit DL data in a UL subframe or UL control information in a DL subframe based on traffic conditions, allowing the system to adapt traffic patterns while maintaining efficient HARQ-ACK transmission within single subframes
Solution Approach 2:
The patent changes the parameter of subframe function assignment by allowing DL or UL subframes to be reassigned based on immediate traffic needs. The base station can change the operational mode of subframes dynamically, transforming conventional static TDD configurations into adaptive structures that reduce latency
2Reliability
If guard period is inserted between xPDSCH and xPUCCH, then switching time and propagation delay are accommodated, but subframe structure complexity increases
Solution Approach 1:
The guard period is preliminarily inserted into the subframe structure between the DL portion (xPDSCH) and UL portion (xPUCCH). This preliminary preparation of the guard period ensures that switching time and propagation delay are already accounted for in the subframe design, allowing reliable transitions without adding operational complexity during actual transmission
Data Source
AI summary
Technology for a user equipment (UE) using a self-contained time division duplex (TDD) subframe to communicate with an eNodeB within a wireless communication network is disclosed. The UE can determine, at the UE, an advanced physical uplink control channel (xPUCCH) resource index to designate one or more physical resources for transmission of the xPUCCH, wherein the one or more physical resources are multiplexed using at least one or more of frequency division multiplexing (FDM), code division multiplexing (CDM), or combination thereof. The UE can signal a transceiver of the UE to transmit to the eNodeB up link control information (UCI) using the one or more physical resources designated by the xPUCCH resource index.