PLC Signal Sending Method With Intra-Payload Pilot Insertion
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Solution Overview
Problem
In power line communication, long frame lengths lead to low channel estimation accuracy and data decoding accuracy due to the time-varying nature of the channel, as the receive end relies solely on preamble-based channel estimation.
Innovation Solution
Inserting pilot time domain symbols between OFDM symbols in the payload field of the physical layer frame to improve channel estimation accuracy, allowing the receive end to better track channel changes and enhance data decoding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a relatively long frame length is set to transmit a large amount of information, then the information transmission capacity is improved, but the channel estimation accuracy deteriorates because the receive end cannot reflect the time-varying characteristic of the channel
Solution Approach 1:
The patent divides the long frame into multiple segments by inserting pilot symbols at regular intervals between OFDM symbols. This segmentation allows the receive end to perform channel estimation at multiple points throughout the frame, capturing time-varying channel characteristics that would be missed by a single preamble-based estimation at the beginning of the frame.
Solution Approach 2:
The patent introduces pilot symbols as intermediary reference signals between the data-carrying OFDM symbols. These pilot symbols serve as mediators that enable the receive end to estimate and track channel variations throughout the transmission, bridging the gap between the initial preamble estimation and the actual data symbols affected by time-varying channel conditions.
2Measurement precision
If pilot symbols are inserted between OFDM symbols to improve channel estimation accuracy, then the channel estimation accuracy is improved, but the bandwidth and pilot resources are consumed
Solution Approach 1:
The patent applies partial action by inserting pilot symbols at selective intervals rather than continuously. The patent specifies inserting pilot symbols between every k OFDM symbols (where k≥1), allowing the system to achieve adequate channel tracking with a fraction of the pilot overhead compared to continuous pilot insertion, thus balancing accuracy improvement with resource conservation.
Solution Approach 2:
The patent enables dynamic adjustment of the pilot insertion interval parameter k. By changing this parameter, the system can adapt the pilot density to match channel conditions and requirements - using smaller k values for rapidly varying channels requiring higher estimation accuracy, and larger k values for stable channels where resources can be conserved.
Data Source
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AI summary
The present invention discloses a signal sending method and apparatus, to improve channel estimation accuracy of a receive end, so as to improve data decoding accuracy of the receive end. The method is applied to a system whose physical layer frame structure includes a preamble and a payload PL field. The method includes: inserting one or more pilot time domain symbols between OFDM time domain symbols in the PL field to obtain a physical layer frame; and sending the physical layer frame to a receive end, where the preamble and the pilot time domain symbol are used together by the receive end to perform channel estimation.