OFDM Interleaving Unit Dynamic Priority Adjustment
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Solution Overview
Problem
Conventional OFDM systems in DVB-T face limitations in dynamically adjusting priority ratios of high-priority (HP) and low-priority (LP) data within subcarriers, leading to performance degradation due to fixed interleaving rules, which affects error correction and user satisfaction, especially in environments with diverse receiving devices.
Innovation Solution
An OFDM transmitting and receiving device that employs a transmission processing unit to generate subcarriers with varying priorities and an interleaving unit that alternately applies pre-defined interleaving rules to change the positions of HP and LP subcarriers periodically, allowing for dynamic adjustment of priority ratios and improved error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed interleaving rules are used in conventional OFDM systems, then device complexity is reduced, but error correction performance degrades due to continuous channel fading
Solution Approach 1:
The patent applies dynamics by making the interleaving rule changeable over time. Specifically, the interleaving rule is modified based on channel conditions or time variations, allowing the system to adapt to changing channel fading patterns. This dynamic adjustment prevents continuous degradation from fading while maintaining manageable complexity through structured rule changes.
Solution Approach 2:
The patent implements periodic action by changing the interleving rule at regular intervals or for different OFDM symbols. This periodic variation ensures that subcarriers experiencing fading in one period are likely to be in different positions in subsequent periods, preventing continuous degradation while using a systematic approach that limits complexity.
2Adaptability or versatility
If hierarchical transmission with fixed priority ratios is used, then device complexity is reduced, but adaptability to diverse receiving devices deteriorates
Solution Approach 1:
The patent makes the priority ratio dynamic by allowing adjustment based on receiving device characteristics or channel conditions. Different priority ratios can be applied to different OFDM symbols or subcarrier groups, enabling adaptation to diverse receiving devices while maintaining structured processing through predefined adjustment rules.
Solution Approach 2:
The patent changes the priority ratio parameter to adapt to different receiving devices. By modifying this key parameter based on device capabilities or channel conditions, the system achieves versatility without requiring complete redesign of the transmission structure, thus limiting complexity increase.
3Reliability
If subcarriers with same priority are bound together, then manufacturing precision is improved, but reliability deteriorates due to frequency fading in specific subcarrier areas
Solution Approach 1:
The patent applies dynamics by changing the binding pattern of subcarriers with the same priority across different OFDM symbols or time periods. This dynamic reconfiguration ensures that subcarriers experiencing fading in one period are not consistently bound together, improving error restoration while maintaining reasonable allocation precision through structured patterns.
Solution Approach 2:
The patent implements periodic action by periodically changing which subcarriers are bound together. This periodic reconfiguration prevents continuous exposure to fading in specific subcarrier areas while maintaining systematic allocation that preserves manufacturing precision through predefined binding rules.
Data Source
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AI summary
An orthogonal frequency-division multiplexing (OFDM) device is disclosed. The OFDM device includes a transmission processing unit to generate subcarriers having different priority levels, an interleaving unit to sequentially select one of a predetermined plurality of interleaving rules, and to interleave the subcarriers, and a transmitting unit to output an OFDM symbol consisting of the interleaved subcarriers through a wireless channel. This prevents continual fading from occurring.