High Capacity Waveform Signal Processing for Satellite Data Rates
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Solution Overview
Problem
Current signal processing technologies are inadequate for efficiently increasing forward link data rates in satellite communications, particularly in multi-point topologies, and lack robustness in channel acquisition and reliability.
Innovation Solution
The implementation of a High Capacity Waveform (HCW) signal processing method using techniques such as high level data link control, scrambling with digital logic, variable rate low density parity check (LDPC) codes, quadrature phase-shift keying (QPSK) or binary phase-shift keying (BPSK) modulation, differential binary phase-shift keying (DBPSK) for pilot and start of message sequences, and root raised cosine (RRC) filtering, along with an Advanced Software Definable Radio (ASDR) system that includes a modular enclosure, baseband board, FPGA complex, cryptographic engine, and RF module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current signal processing technologies are used, then system complexity is maintained at acceptable levels, but forward link data rates cannot be efficiently increased
Solution Approach 1:
The signal processing system is divided into distinct functional modules including HDLC encoding, scrambling, variable rate LDPC encoding, and QPSK/BPSK modulation. Each module handles a specific aspect of the signal processing chain, allowing independent optimization and implementation while achieving high data rates through coordinated operation of these segmented components.
Solution Approach 2:
The system employs variable rate LDPC codes that can dynamically adjust the coding rate based on channel conditions and data rate requirements. This dynamic adaptation allows the system to optimize the balance between data rate and error correction capability, enabling efficient increase of forward link data rates while maintaining reliability.
2Productivity
If advanced modulation techniques are implemented to increase data rates, then forward link capacity improves, but receiver power requirements increase
Solution Approach 1:
The system replaces traditional high-power signal amplification approaches with sophisticated digital signal processing techniques including variable rate LDPC decoding and advanced modulation schemes. This substitution of mechanical/power-intensive methods with intelligent digital processing allows high data rates to be achieved while reducing receiver power consumption through more efficient signal detection and error correction algorithms.
3Reliability
If robust error correction is applied to improve reliability, then data recovery reliability increases, but processing overhead increases
Solution Approach 1:
The system utilizes variable rate LDPC codes where the coding rate parameter can be changed based on channel conditions and reliability requirements. By adjusting the code rate (e.g., from 1/2 to 3/4 or higher), the system can optimize the balance between error correction capability and processing overhead, achieving robust channel acquisition reliability when needed while reducing overhead in better channel conditions.
Data Source
AI summary
The invention broadly encompasses a signal processor of a High Capacity Waveform (HCW) that includes a method and system for generating the HCW, the method comprising the steps of receiving an encrypted source data packet and modulating a received encrypted source data signal representing the packet, wherein the modulating step further comprises the steps of encoding with high level data link control, scrambling the modulated signal, wherein the scrambling comprises applying digital logic, and encoding the scrambled signal, wherein the encoding comprises using a variable rate low density parity check (LDPC) code for forward error correction (FEC).