Uplink Transmission in TDD Systems via Sparse Vector Signaling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In time division duplex (TDD) systems, existing methods incur significant latency due to the need for terminals to wait for resource allocation and processing, which hinders ultra-reliable and low latency communications (URLLC) required for applications like real-time virtual reality and factory automation.

Innovation Solution

The method involves a base station allocating a time period for uplink transmission within the downlink period and using compressed sensing to generate and transmit a sparse vector signal, allowing terminals to recover the signal and transmit data quickly, thereby reducing waiting and processing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a terminal waits for resource allocation in traditional TDD scheduling, then resource allocation can be completed properly, but transmission latency increases significantly

Engineering Contradiction:

Improvetransmission latencyVSAvoidresource allocation reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The base station pre-allocates uplink transmission resources within the downlink period and notifies terminals of these allocations in advance. Terminals can immediately transmit pre-buffered data without waiting for traditional scheduling cycles, reducing transmission latency while maintaining reliable resource allocation through predetermined assignments.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Terminals autonomously determine whether to use pre-allocated resources by checking if they have data to transmit and if the current link direction matches. This self-service approach eliminates the need for continuous scheduling requests and base station decisions, significantly reducing scheduling latency while ensuring reliable resource usage.

Inventive Principle:

Principle #25Self-service

2Loss of time

If the base station uses traditional scheduling to allocate uplink resources, then resource allocation is reliable, but processing latency increases due to multiple signaling steps

Engineering Contradiction:

Improveprocessing latencyVSAvoidresource allocation accuracy

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent extracts the resource allocation decision-making process from the traditional interactive scheduling loop and embeds it directly into the downlink signal transmission. The base station includes uplink resource allocation information in downlink signals, eliminating the need for separate scheduling requests, grants, and acknowledgments, thus reducing processing latency while maintaining allocation accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges downlink signal transmission with uplink resource allocation notification into a single process. By combining these functions, the system eliminates multiple signaling steps and reduces processing latency while ensuring reliable resource allocation through integrated signal design.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If TDD systems separate downlink and uplink into distinct time periods, then resource management is simplified, but waiting time increases when data transmission direction does not match current link direction

Engineering Contradiction:

Improveresource management complexityVSAvoidwaiting time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic resource allocation within the TDD framework by allowing uplink transmission opportunities within downlink periods based on terminal data buffer status and channel conditions. This dynamic approach reduces waiting time while maintaining the overall simplified TDD resource management structure.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11233626B2Uplink transmission method and device in time-division duplex communication system

Publication Date: 2022.01.25 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

AI summary

An operation method of a base station in a time division duplex communication system includes: a step for setting a time period in which a terminal can transmit an uplink in a downlink period; a step for generating a sparse vector signal including information about the time period; and a step for transmitting the sparse vector signal to the terminal. In addition, an operation method of the terminal in the time division duplex communication system includes: a step for receiving a part of a sparse vector signal from the base station; a step for recovering the received sparse vector signal by compressed sensing; and a step for transmitting uplink data in a time period instructed in a downlink period based on the basis of the recovered signal.