Physical Layer Network Coding for Satellite Downlink Capacity
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Solution Overview
Problem
Satellite network communications face limited downlink (DL) and forward link (FL) capacity due to frequency and power limitations, making existing methods to enhance capacity impractical due to cost, complexity, size, and power considerations.
Innovation Solution
Implementing a physical layer network coding architecture that replaces DL transmission channels with a single broadcast downlink channel, using XOR network coding and forward error correction (FEC) to increase capacity and improve error protection, while allowing media access control (MAC) layer-based network coding to enhance overall system capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher gain antenna, dynamic resource allocation, or statistical multiplexing is used to improve DL and FL performance, then communication capacity is improved, but cost, complexity, size, and power consumption increase
Solution Approach 1:
The patent merges multiple separate downlink transmission channels into a single broadcast downlink channel by applying physical layer network coding. Instead of transmitting separate signals to each user terminal, the system combines data streams using XOR operations at the physical layer, allowing multiple users to receive their intended data through one consolidated channel, thereby reducing system complexity while maintaining capacity
Solution Approach 2:
The single broadcast downlink channel serves multiple user terminals simultaneously through network coding techniques. The same transmitted signal provides useful information to multiple recipients, each of whom can decode their intended data by combining the broadcast signal with their own transmitted signal, making the channel universally useful for multiple users
2Productivity
If higher gain antenna, dynamic resource allocation, or statistical multiplexing is used to improve DL and FL performance, then communication capacity is improved, but power consumption increases
Solution Approach 1:
The patent consolidates multiple downlink transmissions into a single broadcast channel using physical layer network coding. By merging the transmission resources, the system reduces the total power required for downlink communications while serving the same number of users, as the combined signal is transmitted once rather than multiple separate high-power signals
3Reliability
If separate downlink transmission channels are used for each user terminal, then individual user communication is ensured, but downlink satellite capacity requirements increase
Solution Approach 1:
The patent merges multiple individual downlink channels into a single broadcast channel through network coding. Each user terminal receives the same broadcast signal but recovers its intended communication by XORing the received signal with its own transmitted signal, ensuring individual communication reliability while using only one downlink channel
Solution Approach 2:
The network coded broadcast signal acts as an intermediary that carries information for multiple users simultaneously. Each user terminal uses its own transmitted signal as a key to decode the intermediary broadcast signal and recover its intended communication, maintaining reliability through the intermediary mechanism
Data Source
AI summary
A physical layer network coding architecture is provided to increase downlink capacity for satellite network architectures. For instance, a network coding controller may perform a XOR network coding operation on FEC encoded information received from a first terminal and second terminal, and broadcast a single downlink message containing the XOR network coded information to the first and second terminal.