Transceiver 4B5B Coding Module for DC-Balanced Data Transmission
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Solution Overview
Problem
The IEEE 10BASE-T1S standard's 4B5B coding and differential Manchester encoding result in significant bandwidth overhead, limiting flexibility in topology and data transmission efficiency, particularly for applications requiring lower data rates like IoT and industrial control.
Innovation Solution
A coding module that performs 4B5B mapping of four-bit data groups to five-bit codewords, specifically selecting from codewords with two zeros and three ones or three zeros and two ones, reducing the need for additional differential Manchester encoding and maintaining DC balance, while allowing for error detection and control information transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 4B5B coding and differential Manchester encoding are used as mandated by IEEE 10BASE-T1S, then data transmission and control are covered, but coding overhead increases by 25% and required transmission rate doubles
Solution Approach 1:
The patent modifies the 4B5B coding parameters by selecting specific codewords with balanced numbers of zeros and ones (either 2 zeros and 3 ones, or 3 zeros and 2 ones). This parameter change maintains the 25% overhead while improving DC balance and enabling error detection capabilities, thereby resolving the contradiction between reliability and transmission efficiency.
Solution Approach 2:
The patent applies local quality by imposing specific constraints on codeword composition (balanced zeros and ones) rather than using all possible 4B5B codewords. This localized modification of codeword properties maintains compatibility with the standard while improving overall system performance in terms of DC balance and error detection.
2Stability of the object's composition
If codewords with balanced zeros and ones are selected for 4B5B mapping, then DC balance is enhanced and error detection is enabled, but codeword selection complexity increases
Solution Approach 1:
The patent changes the selection criteria for codewords from the full 4B5B set to a restricted subset with balanced zero-one composition. This parameter change in selection criteria simplifies the overall system by enabling error detection and improving DC balance, while the complexity increase is minimal and confined to the mapping table.
3Adaptability or versatility
If IEEE 10BASE-T1S standard encoding is used, then compatibility with existing systems is maintained, but bandwidth overhead is significant and flexibility in topology is limited
Solution Approach 1:
The patent changes the coding parameters within the 4B5B framework to use only codewords with balanced zero-one distribution. This maintains compatibility with IEEE 10BASE-T1S while reducing effective bandwidth consumption by improving transmission efficiency and enabling better topology flexibility for IoT and industrial control applications.
Data Source
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AI summary
A coding module for a transceiver, the coding module comprising circuitry configured to: receive transmit-data comprising a bitstream for transmission by the transceiver; provide for 4B5B mapping of groups of four bits of the transmit-data to five bit codewords, comprising groups of five bits, for said transmission, wherein said codewords selected to represent the groups of four bits of the transmit-data comprise a predetermined mapping and are only selected from: a) five bit codewords that comprise two zeros and three ones; and b) five bit codewords that comprise three zeros and two ones.