Constant Baud Rate Communication via Sequence Encoding
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Solution Overview
Problem
Conventional adaptive communication systems face challenges in maintaining a constant baud rate while adjusting data rates in response to changing channel noise conditions, requiring changes to transmitter and receiver hardware and software, which is costly and complex.
Innovation Solution
Encoding data with pseudo random number sequences or Barker sequences before transmission, multiplying energy per bit by the length of the encoding sequence to maintain a constant baud rate while varying the effective data rate, allowing changes in data rate without altering the baud rate or hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data rate is adjusted in response to changing channel conditions, then system BER is maintained, but baud rate changes requiring hardware and software modifications
Solution Approach 1:
The patent segments the data stream by encoding data bits with pseudo-random sequences (e.g., 8 data bits encoded with 32-chip Barker sequence). This creates multiple encoded symbols from fewer data bits, allowing the physical layer to operate at a constant baud rate while the logical data rate varies. The segmentation separates the constant-rate physical transmission from the variable-rate logical data flow.
Solution Approach 2:
The patent introduces an intermediary encoding layer using pseudo-random sequences between the data source and the physical transmission medium. This intermediary process (encoding data with PRNS) transforms variable-rate data into constant-rate encoded symbols, absorbing the rate variations without propagating them to the hardware layer. The matched filter at the receiver acts as the corresponding intermediary for decoding.
2Reliability
If power is increased to respond to noise conditions, then Eb/No ratio is maintained, but transmission is limited by FCC regulations and operational considerations
Solution Approach 1:
The patent changes the parameter of energy per bit by encoding data with sequences of length N, which multiplies the energy per bit by N. This allows the system to maintain the required Eb/No ratio without increasing transmitted power, effectively trading sequence length for power efficiency. The parameter transformation occurs at the signal processing level rather than the power amplification level.
3Reliability
If coding gain is increased to respond to noise conditions, then system performance is improved, but baud rate changes requiring hardware and software modifications
Solution Approach 1:
The patent applies segmentation by dividing data into blocks that are encoded with pseudo-random sequences of specific lengths (e.g., 32-chip Barker sequences). This segmentation enables coding gain through the encoding process while maintaining constant baud rate, as the encoding operates on data blocks rather than requiring changes to the physical transmission rate.
4Reliability
If data rate is reduced to respond to noise conditions, then Eb/No ratio is maintained, but effective data transmission rate decreases
Solution Approach 1:
The patent applies dynamics by making the encoding sequence length adaptable to channel conditions. The system can dynamically select different sequence lengths (e.g., 8, 16, or 32 chips) based on the noise level, optimizing the balance between reliability (Eb/No) and productivity (effective data rate). This dynamic adaptation allows the system to adjust coding gain without changing the physical baud rate.
Data Source
AI summary
Methods and apparatus for transmitting data at a varying effective data rate (EDR) at a constant baud rate by encoding the data prior to transmission with a sequence. In embodiments, the sequence comprises a pseudo random number sequence, Barker sequence, and/or other sequence. Embodiments of a receiver decode the data transmitted at a varying effective data rate (EDR) at a constant baud rate by encoding the data prior to transmission with a sequence.