Unified Frequency Hopping for TDD Uplink Downlink Retuning

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Solution Overview

Problem

In Time Division Duplex (TDD) systems, especially for TD-LTE, the separate frequency hopping patterns for uplink and downlink data transmissions lead to increased retuning time, power consumption, and resource wastage due to frequent frequency switching, which limits the effective duration and efficiency of data transmission in UEs, particularly in scenarios like deep fading.

Innovation Solution

A data transmission method and device that adjusts the carrier frequency at a predetermined retuning start time for both reception and transmission within a predetermined duration, allowing for consecutive uplink data transmission and downlink data reception according to the TDD uplink-downlink configuration, thereby reducing the need for frequent frequency hopping and optimizing retuning time and power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate frequency hopping patterns are used for uplink and downlink data transmissions, then frequency diversity gain is achieved, but retuning time and power consumption increase

Engineering Contradiction:
Improvefrequency diversity gainVSAvoidretuning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the frequency hopping patterns for uplink and downlink transmissions by configuring them to follow the same hopping sequence and timing. This allows the UE to perform frequency hopping once and maintain the same frequency pattern for both uplink and downlink, eliminating the need for separate retuning operations and reducing overall retuning time while preserving frequency diversity benefits

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal frequency hopping pattern that serves both uplink and downlink transmissions simultaneously. By designing a single frequency hopping configuration that applies to both transmission directions, the system achieves multi-functionality where the same frequency hopping mechanism provides frequency diversity for both uplink and downlink without requiring separate retuning operations

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

2Reliability

If separate frequency hopping patterns are used for uplink and downlink data transmissions, then frequency diversity is achieved, but power consumption increases

Engineering Contradiction:
Improvefrequency diversityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines the frequency hopping operations for uplink and downlink into a single unified process. The UE performs frequency hopping once according to a unified pattern and uses the same frequency sequence for both uplink transmission and downlink reception, eliminating redundant frequency switching operations and reducing power consumption associated with multiple retuning events

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If frequent frequency hopping is performed, then frequency diversity gain is achieved, but the valid data transmission duration is reduced

Engineering Contradiction:
Improvefrequency diversity gainVSAvoidvalid data transmission duration
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies preliminary action by configuring the frequency hopping pattern in advance to align with the TDD uplink-downlink configuration. The frequency hopping is performed at predetermined times that do not conflict with data transmission slots, allowing continuous data transmission without interruption for frequency retuning, thus preserving both frequency diversity gain and valid transmission duration

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If separate frequency hopping patterns are used for uplink and downlink, then independent frequency control is achieved, but resource wastage increases

Engineering Contradiction:
Improveindependent frequency controlVSAvoidresource wastage
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent merges the frequency resource allocation for uplink and downlink by implementing a unified frequency hopping pattern. This unified approach eliminates resource wastage caused by separate frequency hopping operations, as the same frequency resources are efficiently utilized for both uplink and downlink transmissions without redundant frequency switching and associated resource overhead

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3261278B1Data transmission method and device for time division duplex system
Publication Date: 2020.06.17 CHINA ACAD OF TELECOMM TECH
  • EP3261278B1 patent drawingFigure 1~3
  • EP3261278B1 patent drawingFigure 4~6
  • EP3261278B1 patent drawingFigure 7~9

AI summary

A data transmission method and a data transmission device for a TDD system are provided, so as to reduce the frequency hopping operations, reduce the retuning time, prolong a valid duration for the data transmission and reduce the time period for the data transmission, and reduce the power consumption. The data transmission method includes steps of: at a predetermined retuning start time point, adjusting, by a UE, a carrier frequency for data reception and transmission within a predetermined retuning duration so as to acquire the adjusted carrier frequency; and performing, by the UE, uplink data transmission and downlink data reception at the adjusted carrier frequency with a network device within a consecutive duration in accordance with a TDD uplink-downlink configuration. The consecutive duration is a duration from a current retuning end time point to a next retuning start time point.