Signal Point Movement for DC Offset Compensation
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Solution Overview
Problem
In high-speed wireless communication systems, such as millimeter-wave communication, DC offset components caused by AC coupling lead to errors and reduced encoding efficiency due to the need for additional bit insertion in data encoding techniques or scramblers, which can generate bit deviations and worsen error rates, especially in multi-level modulation systems like 16 QAM and 64 QAM.
Innovation Solution
A method that monitors signal level deviations in transmission symbol strings, specifies target symbols at the outermost positions of these deviations, and moves their signal points outward to reduce DC offset and low-frequency components, thereby reducing errors without additional bit insertion, using a monitoring unit, symbol specifying unit, and signal point moving unit within the transmission apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data encoding techniques (such as 8b/10b encoding, bit stuffing, or Fibonacci coding) are used to diffuse transmission bits and avoid DC offset components, then DC balance is improved, but encoding efficiency is reduced due to additional bit insertion
Solution Approach 1:
The invention extracts and removes symbols that cause DC imbalance from the transmission symbol sequence. By identifying symbols with signal levels that contribute to DC offset and selectively removing or adjusting them, the system achieves DC balance without inserting additional bits, thus resolving the contradiction between reliability and encoding efficiency
Solution Approach 2:
Instead of adding bits to achieve DC balance (conventional approach), the invention takes the opposite approach by removing or adjusting existing symbols that cause DC imbalance. This inversion of the conventional method eliminates the need for additional bit insertion while maintaining DC balance
2Stability of the object's composition
If a scrambler is used to uniformly disperse bits, then bit distribution is improved, but DC imbalance occurs in the short term due to bit deviation, worsening the error rate
Solution Approach 1:
The invention implements a feedback mechanism where the DC balance status is continuously monitored and used to control symbol adjustment. By feeding back the DC offset information to the transmission side, the system can dynamically adjust symbols to maintain DC balance, preventing short-term DC imbalance and reducing error rates
Solution Approach 2:
The invention performs preliminary adjustment of symbols before transmission to prevent DC imbalance. By proactively identifying and correcting symbols that would cause DC offset in advance, the system avoids short-term DC imbalance and associated error rate deterioration
3Productivity
If multi-level modulation systems (such as 16 QAM, 64 QAM) are used to increase data rate, then communication speed is improved, but DC offset components have a non-negligible effect on multi-level determination, increasing errors
Solution Approach 1:
The invention applies local quality adjustment by selectively modifying only those symbols that cause DC imbalance, rather than uniformly adjusting all symbols. This targeted approach maintains the integrity of most symbols while correcting specific DC offset issues, preserving signal determination accuracy in multi-level modulation systems
Data Source
AI summary
A transmission apparatus configured to communicate with a reception apparatus. The transmission apparatus comprising a monitoring unit, a symbol-specifying unit, a signal point moving unit, and a transmission unit. The monitoring unit monitors a total amount of deviations of signal levels in signals forming transmission symbol strings. The symbol specifying unit specifies target symbols from the transmission symbol strings based on the total amount of deviations of the signal levels. The signal level is at an outermost position on an opposite side of a plurality of deviations of the signal levels. The signal point moving unit moves positions of signal points of the target symbols outward. The transmission unit transmits a signal forming a transmission symbol string including the symbols, in which the positions of the signal points are moved, to the reception apparatus.