Chip-to-Chip Bus Signaling with Spherical Codes for Pin Efficiency
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Solution Overview
Problem
Current communication bus technologies face limitations in pin efficiency and noise resilience, particularly in high-speed applications where additional improvements are needed to balance pin efficiency and noise resilience, and existing methods may not be suitable for non-power-of-two wire configurations or high-rate data transfer.
Innovation Solution
The use of spherical codes and permutation modulation codes to map information signals onto a set of physical signals, ensuring that the sum of vector signal components sum to zero and maintaining constant total power consumption, which enhances noise resilience and pin efficiency by allowing for efficient encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of wires in the communication bus is increased to increase communication speed, then the communication speed is improved, but the number of pins required increases and pin efficiency decreases
Solution Approach 1:
The patent combines multiple signal functions into a reduced set of wires by using spherical codes that map high-dimensional data vectors to lower-dimensional physical signal representations. This merging approach allows multiple information channels to share fewer physical wires through sophisticated encoding schemes, thereby increasing communication speed while reducing pin requirements.
Solution Approach 2:
The patent transforms the communication problem from a one-dimensional wire count constraint to a multi-dimensional signal space problem. By using spherical codes in high-dimensional space and projecting them onto fewer physical wires, the system achieves higher effective bandwidth without proportionally increasing the number of pins, thus resolving the contradiction between speed and pin quantity.
2Power
If transmit power is increased to improve communication performance, then signal strength is improved, but noise and interference increase and performance deteriorates
Solution Approach 1:
The patent changes the fundamental parameters of signal representation by using spherical codes with constant norm (constant total power). This ensures that signal energy is distributed optimally across the available wires, maintaining strong signal strength while minimizing peak power requirements and reducing the generation of noise and interference through efficient energy utilization.
Solution Approach 2:
The patent converts the potential harm of power consumption into benefit by using constant-norm spherical codes that distribute power efficiently. The constraint of constant total power prevents any single wire from consuming excessive power that would generate noise, while the spherical code structure ensures robust noise resilience through geometric separation of code points in signal space.
3Reliability
If signal swings are increased to improve resilience against Gaussian noise, then noise resilience is improved, but power consumption increases and more interference is generated
Solution Approach 1:
The patent changes the signal representation parameters by using spherical codes where the norm (total power) is constrained to be constant. This allows the system to achieve noise resilience through the geometric structure of the code (minimum distance between code points) rather than through increased signal swings, thereby maintaining reliability without proportionally increasing power consumption.
4Reliability
If more wires are used to achieve better noise resilience, then noise resilience is improved, but pin efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by moving the noise resilience achievement from the dimension of wire count to the dimension of signal space geometry. Spherical codes provide noise resilience through their geometric structure in high-dimensional space, allowing the system to achieve reliability with fewer physical wires by exploiting the additional dimensionality of the coded signal representation.
Data Source
AI summary
In bus communications methods and apparatus, a first set of physical signals representing the information to be conveyed over the bus is provided, and mapped to a codeword of a spherical code, wherein a codeword is representable as a vector of a plurality of components and the bus uses at least as many signal lines as components of the vector that are used, mapping the codeword to a second set of physical signals, wherein components of the second set of physical signals can have values from a set of component values having at least three distinct values for at least one component, and providing the second set of physical signals for transmission over the data bus in a physical form.