Adaptive Symbol Slicing for Mixed-Modulation Packet Decoding
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Solution Overview
Problem
Receivers face challenges in decoding symbols with different modulations within the same packet, as they need to determine the proper modulation for each symbol set to accurately demodulate, which can lead to errors due to interference, especially when some modulations are unknown before slicing.
Innovation Solution
A system comprising an Analog Front End (AFE), a Decision Based Filter (DBF), and a Physical Coding Sublayer (PCS) is used, where the PCS identifies the modulation of dynamically modulated symbols and provides feedback to a slicer to use the appropriate slicer function, and the DBF adapts filter coefficients using slicing errors to reduce error propagation and improve signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple modulations are used within the same packet to increase data transfer rates, then productivity is improved, but reliability deteriorates due to error propagation and difficulty in determining proper modulation for each symbol
Solution Approach 1:
The patent applies preliminary action by using a fine slicer to process symbols before the main slicing operation. The fine slicer creates preliminary slicing results that are then used by the Physical Coding Sublayer to identify modulation information and determine the appropriate modulation for each symbol set. This preliminary processing enables the system to handle dynamically modulated symbols accurately, resolving the contradiction between using multiple modulations for higher data rates and maintaining decoding reliability.
2Adaptability or versatility
If the receiver uses a fixed slicer configuration, then device complexity is reduced, but adaptability deteriorates because it cannot handle dynamically modulated symbols with different modulations within the same packet
Solution Approach 1:
The patent applies segmentation by dividing the slicing function into two distinct components: a fine slicer and a main slicer. The fine slicer processes all symbols to generate preliminary results, while the main slicer processes symbols based on modulation information identified from the fine slicing results. This segmentation allows the receiver to handle multiple modulations dynamically without requiring a completely reconfigurable system, thus improving adaptability while controlling complexity.
Solution Approach 2:
The patent introduces an intermediary component - the Physical Coding Sublayer (PCS) - that acts as a mediator between the fine slicer and the main slicer. The PCS identifies modulation information from the fine slicing results and determines the appropriate modulation for each symbol set, then provides this information to control the main slicer's operation. This intermediary enables dynamic adaptation to different modulations while keeping the overall receiver structure manageable.
Data Source
AI summary
Reducing decision based filter error propagation by feedback from a physical coding sublayer (PCS) to a slicer. One method includes: receiving a frame comprising symbols of at least two different modulation orders that use subsets of a symbol superset; slicing the received symbols according to the highest modulation order by a slicer having slicing functions suitable for the different modulations; identifying frame boundaries and modulation information, which are modulated according to a predetermined modulation order; using the identified modulation information for determining the modulation of a nonempty set of dynamically modulated symbols in the received frame; and providing the slicer with an indication of which slicer function output to use for feeding a decision based filter.