Dynamic Guard Interval Adaptation for Multi-Carrier Data Transmission

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In multi-carrier data transmission systems, the use of a fixed cyclic prefix duration within a cell leads to suboptimal throughput and increased inter-symbol interferences due to varying delay spreads among mobile subscribers, as it either underutilizes or overutilizes transmission power based on the distance from the base station.

Innovation Solution

Adapting the cyclic prefix duration based on the distance between mobile subscribers and the base station by using at least two different guard intervals, determined by propagation delay measurements, to optimize data transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed cyclic prefix duration is used within a cell, then the system complexity is reduced and ease of operation is improved, but throughput is reduced and inter-symbol interferences increase due to varying delay spreads among mobile subscribers

Engineering Contradiction:
Improveease of operationVSAvoidthroughput
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements dynamic adaptation of the cyclic prefix duration by allowing different mobile subscribers to use different guard interval lengths (first guard interval for short delay spread, second guard interval for long delay spread) based on their specific channel conditions, thereby optimizing throughput for each subscriber while maintaining system operational simplicity through standardized procedures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of guard interval duration from a fixed value to a variable parameter that can take at least two different values (first and second guard intervals) depending on the delay spread characteristics of individual communication links, thus resolving the contradiction between operational simplicity and throughput optimization

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a fixed cyclic prefix duration is used within a cell, then device complexity is reduced, but inter-symbol interferences increase due to varying delay spreads among mobile subscribers

Engineering Contradiction:
Improvedevice complexityVSAvoidinter-symbol interferences
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by allowing each mobile subscriber to use a guard interval duration specifically adapted to their local channel conditions (delay spread), rather than applying a uniform guard interval to all subscribers. This ensures that each subscriber experiences minimal inter-symbol interference appropriate to their specific environment

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically assigns different guard interval durations (first or second) to different mobile subscribers based on their delay spread characteristics, enabling the system to adapt to varying channel conditions without increasing overall device complexity through standardized adaptation procedures

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If a longer cyclic prefix is used to cover maximum delay spread, then inter-symbol interferences are reduced, but data volume is reduced and transmission power is wasted

Engineering Contradiction:
Improveinter-symbol interferencesVSAvoidtransmission power
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent changes the guard interval duration parameter from a single fixed value to at least two different values (first and second guard intervals), allowing the system to match the guard interval length to the actual delay spread requirements of each communication link, thereby avoiding the waste of transmission power associated with using unnecessarily long guard intervals

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of applying an excessively long guard interval to all subscribers (which would eliminate inter-symbol interference for everyone but waste power for those with short delay spread), the patent applies partial action by using different guard interval durations tailored to each subscriber's actual needs, thus avoiding unnecessary energy consumption

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP1942623A1Method for data transmission using a block guard interval, subscriber and system
Publication Date: 2008.07.09 NOKIA SIEMENS NETWORKS GMBH & CO KG
  • EP1942623A1 patent drawingFigure 1
  • EP1942623A1 patent drawingFigure 2
  • EP1942623A1 patent drawingFigure 3

AI summary

The present invention relates to a method for multi-carrier data transmission within a cell-based communication system, comprising the steps: providing for data transmission purposes between a first and second subscribers a corresponding communication link, wherein the second subscribers are located within the same cell of the system and wherein during the data transmission a frame-based multi-carrier signal is send from one subscriber to the other utilizing the communication link, and providing at least two different guard intervals for the different communication links within the same cell to reduce cross-talks between the sub-carriers.. The present invention further relates to a subscriber and system for data transmission.