TDS-OFDM Spectrum Direction Verification for Inversion Correction

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Solution Overview

Problem

Spectrum inversion in wireless communication signals, particularly in DTMB standards, leads to incorrect decoding of real and imaginary parts, degrading receiver performance due to improper transmission and reception of signal components.

Innovation Solution

An apparatus and method that detect the spectrum direction of TDS-OFDM signals using TPS, LDPC, or NR decoding, adjusting the real and imaginary parts as needed to correct the signal, ensuring accurate data recovery by swapping or inverting components to align with the intended transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmitter end does not transmit the real part and imaginary part properly, then spectrum inversion occurs, but the receiver end fails to decode the received input correctly

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoiddata decoding accuracy
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by performing spectrum direction verification before the main decoding process. The receiver end checks the spectrum direction of the received signal in advance, and if inversion is detected, corrects it by swapping real and imaginary parts before proceeding with normal decoding, thereby preventing decoding failures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the decoding result to verify spectrum direction. The receiver end performs an initial decoding attempt, checks whether the result is valid, and if not, feeds back to adjust the signal processing by swapping real and imaginary parts, then re-attempts decoding until successful

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If the local oscillation signal frequency is mismatched, then down-conversion produces incorrect intermediate frequency, but the receiver architecture cannot adapt to different spectrum directions

Engineering Contradiction:
Improvereceiver adaptability to spectrum directionVSAvoidreceiver architecture complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the receiver architecture dynamically adaptable to different spectrum directions. Instead of requiring multiple fixed architectures, the system dynamically adjusts the signal processing path by swapping real and imaginary parts based on detected spectrum direction, allowing a single receiver to handle both inverted and non-inverted signals

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the signal parameters (real and imaginary parts) rather than changing the hardware architecture. When spectrum inversion is detected, the system changes the parameter arrangement by swapping real and imaginary components, enabling the same hardware to process signals with different spectrum directions

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8804859B2Methods and apparatuses for dealing with spectrum inversion
Publication Date: 2014.08.12 MEDIATEK INC
  • US8804859B2 patent drawing
  • US8804859B2 patent drawing
  • US8804859B2 patent drawing

AI summary

An apparatus of processing a time domain synchronous orthogonal frequency-division-multiplexing (TDS-OFDM) signal is provided. The apparatus includes a receiving block and a demodulating block. The receiving block receives the TDS-OFDM signal, and generates a down-converted signal according to the received TDS-OFDM signal. The demodulating block is coupled to the receiving block, and demodulates the down-converted signal to generate a transport stream. The demodulating block has a transmission parameter signaling (TPS) decoder implemented for performing a TPS decoding operation to generate a TPS decoding result and verifying a spectrum direction of the received TDS-OFDM signal according to the TPS decoding result.