Multicarrier Symbol Boundary Timing Using Identical Training Pairs

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Solution Overview

Problem

Multicarrier data transmission systems face challenges in determining accurate symbol boundaries due to interference from inter-symbol and inter-carrier interference, which affects transmission performance, especially in systems with longer loops or varying channel conditions.

Innovation Solution

The method involves transmitting pairs of identical symbols during a training sequence, allowing the receiver to estimate noise and select the symbol boundary timing with minimal interference, which can be performed in either the time or frequency domain, and using correlation values to determine the optimal timing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional symbol boundary detection methods are used in multicarrier systems, then the system can operate, but inter-symbol and inter-carrier interference increases especially in longer subscriber loops, degrading transmission performance

Engineering Contradiction:

Improvetransmission performanceVSAvoidinter-symbol and inter-carrier interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by transmitting a training sequence containing pairs of identical symbols before actual data transmission. This allows the receiver to pre-determine the optimal symbol boundary timing by analyzing the correlation between identical symbol pairs, establishing a reference that minimizes interference for subsequent data reception in longer subscriber loops

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by transmitting pairs of identical symbols in the training sequence. By having exact copies of the same symbol transmitted consecutively, the receiver can correlate these identical pairs to accurately identify symbol boundaries and minimize the effects of inter-symbol and inter-carrier interference without requiring knowledge of the actual data content

Inventive Principle:

Principle #26Copying

2Reliability

If accurate symbol boundary timing is achieved through training sequences with identical symbol pairs, then interference is reduced and transmission performance improves, but the system complexity and training overhead increase

Engineering Contradiction:

Improvesymbol boundary determination accuracyVSAvoidtraining sequence processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying the position of identical symbol pairs within the training sequence and evaluating different correlation metrics. The receiver tests multiple potential symbol boundary positions and selects the timing that maximizes the correlation between identical symbol pairs, thereby optimizing the parameter of symbol boundary accuracy while managing processing complexity through structured evaluation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7643582B2Method and system for determining symbol boundary timing in a multicarrier data transmission system

Publication Date: 2010.01.05 MARVELL ASIA PTE LTD

AI summary

Improved techniques for acquiring symbol boundary timing at a receiver of a multicarrier data transmission system during a training sequence are disclosed. One aspect is symbol boundary determination at a receiver wherein minimal interference is used as a criterion in selecting from a plurality of potential symbol boundary timings. The symbol boundary determination at the receiver can be performed in a time domain or a frequency domain manner. Another aspect pertains to an improved training sequence wherein pairs of identical symbols are transmitted by a transmitter. These symbols can be supplied to the transmitter in a time domain or a frequency domain manner.