Spread Spectrum Slip Time Encoding Data Rate
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Solution Overview
Problem
Spread spectrum systems face a reduction in bandwidth due to the need to process a large number of PN-codes, leading to increased hardware complexity and reduced data rate, as each additional PN-code requires complex correlation comparisons.
Innovation Solution
The introduction of a Spread Spectrum Slip Time encoding scheme, which encodes data by varying the slip time between PN-codes, allowing additional data values to be transmitted by adjusting the spacing between adjacent PN-codes, thereby increasing data rate without significantly increasing hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple PN-codes are used to encode the data stream, then the data rate is improved, but the hardware complexity increases substantially
Solution Approach 1:
The patent introduces a new dimension for data encoding by varying the time spacing (slip time) between consecutive PN-coded data values. Instead of only using different PN-codes to represent different data values, the invention uses the temporal dimension - specifically the number of clock cycles between PN-code transmissions - to encode additional data information. This allows the system to maintain a single PN-code while still achieving higher data rates by encoding multiple bits per transmission through timing variations.
Solution Approach 2:
The patent changes the parameter being used for data encoding from solely the PN-code selection to include the time interval between transmissions. By varying the slip time parameter (the number of clock cycles between consecutive PN-coded values), the system can encode additional data bits without requiring additional PN-codes or increasing the complexity of the correlation logic. This parameter change transforms a single-dimensional encoding scheme into a two-dimensional scheme that achieves higher data rates with the same hardware resources.
2Reliability
If 64 chips are generated and processed to transmit one data bit, then the noise interference robustness is improved, but the effective bandwidth is reduced
Solution Approach 1:
The patent adds a temporal dimension to the spread spectrum encoding by introducing variable slip times between PN-code transmissions. This allows the system to encode multiple data bits within the same chip bandwidth by utilizing time spacing variations. The correlation logic remains unchanged, preserving noise robustness, while the time-based encoding dimension increases the effective data rate without requiring additional bandwidth.
Solution Approach 2:
The patent employs periodic transmission of PN-coded data values with variable intervals (slip times) between them. By using periodic action with varying periods, the system can encode data values in the timing pattern itself. The regular periodic structure maintains the correlation properties needed for noise resistance, while the variable periodicity encodes additional information, thereby increasing data rate without sacrificing reliability.
Data Source
AI summary
A spread spectrum slip time encoding scheme encodes data values with one or more Pseudo Noise (PN) codes and generates a corresponding PN encoded data stream. Other data values are encoded into the PN encoded data stream by varying a slip time between the PN-encoded data values.