Hierarchical Modulation Satellite System for Seamless High-Priority Content Delivery
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Solution Overview
Problem
Current satellite communication systems face inefficiencies in transmitting high and low priority content using different frequencies or polarizations, leading to increased bandwidth usage, higher receiver costs, and potential loss or interference of low priority content when a ground receiver moves between sub-regions.
Innovation Solution
A satellite communication system employing hierarchical modulation with quadrature-phase-shift-keyed (QPSK) high priority content and phase or magnitude offset modulated low priority content, using the same carrier frequency and polarization, and different forward error correction algorithms, along with selective antenna control to minimize interference between sub-regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different frequencies or polarizations are used to separate high and low priority signals, then signal separation is achieved, but bandwidth usage increases and receiver cost increases
Solution Approach 1:
The patent combines high and low priority signals onto the same carrier frequency and polarization by using hierarchical modulation. The high priority signal modulates the carrier first, then the low priority signal modulates the resulting signal, allowing both signals to coexist in the same frequency and polarization resources without interference, thus resolving the contradiction between signal separation and bandwidth efficiency
Solution Approach 2:
The patent implements nesting by having the low priority signal nested within the high priority signal's modulated waveform. The low priority modulation is applied to the already modulated high priority signal, creating a nested structure where both signals occupy the same spectral resources but can be separately decoded at the receiver, eliminating the need for separate frequency or polarization resources
2Reliability
If different frequencies or polarizations are used to separate high and low priority signals, then signal separation is achieved, but receiver hardware and software cost increases
Solution Approach 1:
The patent merges the reception of high and low priority signals into a single receiver chain by using hierarchical modulation on the same frequency and polarization. The receiver only needs to implement hierarchical demodulation algorithms rather than maintaining separate hardware paths for different frequencies or polarizations, significantly reducing receiver complexity and cost while maintaining reliable signal separation
Solution Approach 2:
The patent makes the receiver universal by designing it to handle both high and low priority signals through a single demodulation path. The hierarchical demodulation structure allows the same receiver hardware and software to process signals regardless of which priority level is present, eliminating the need for specialized hardware components for different signal types
3Quantity of substance
If low and high priority content are transmitted at the same carrier frequency into one sub-region, then bandwidth efficiency is improved, but low priority content loss or interference occurs at sub-region boundaries
Solution Approach 1:
The patent applies local quality by using spot beams with specific directional characteristics tailored to each sub-region. Each spot beam is configured to provide coverage with appropriate overlap and transition characteristics at its boundaries, ensuring that low priority content directed to one sub-region does not cause harmful interference to adjacent sub-regions while maintaining bandwidth efficiency through hierarchical modulation
Solution Approach 2:
The patent implements dynamic control of spot beam characteristics to manage boundary conditions. The satellite system dynamically adjusts beam pointing, width, and power distribution to optimize content delivery at sub-region boundaries, ensuring that receivers transitioning between sub-regions maintain reliable high priority content reception while minimizing low priority content interference through real-time beam management
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables seamless transmission of high priority content across sub-region boundaries without loss and reduces low priority content interference by using the same carrier frequency and polarization, optimizing data throughput and service availability while minimizing hardware and software costs.
Implementation Method 1
The high priority content is modulated as a quadrature-phase-shift-keyed (QPSK) signal
Implementation Method 2
The low priority content is a phase offset modulation of the high priority content
Implementation Method 3
The low priority content is a magnitude offset modulation of the high priority content
Implementation Method 4
The antenna elements are utilized selectively to direct a modulated signal from a transmitter to a distinct sub-region within the region
Implementation Method 5
satellite broadcast systems that broadcast high priority content directed at a relatively large region and simultaneously use spot beams to broadcast low priority content over sub-regions within the large region
Implementation Method 6
the plurality of antenna elements are further utilized selectively to preferentially receive a signal from each of the plurality of sub-regions such that a plurality of ground transceivers each located in distinct sub-regions can use the same carrier frequency to send messages to the satellite
Implementation Method 7
The plurality of antenna elements are further utilized selectively to move the first sub-region effective to reduce low priority content interference with the second sub-region
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A satellite communication system (10) using hierarchical modulation to transmit a plurality of modulated signals (12) to sub-regions (16) within a region (14). Each modulated signal includes high priority content and low priority content. The system (10) includes a satellite (20) equipped with a plurality of satellite transmitters (22) coupled to a plurality of antenna elements (24), e.g. a phased array of antenna elements (24). The antenna elements (24) are utilized selectively to direct a modulated signal from a satellite (20) transmitter to a distinct sub-region (16a). The satellite transmitters (22) and antenna also cooperate to broadcast the high-priority content to the region (14) such that a ground receiver (30) traveling from a first sub-region (16a) to an adjacent second sub-region (16b) adjacent will not experience a loss of high-priority content. First low-priority content of a first modulated signal (12a) directed to the first sub-region (16a) is independent of second low-priority content of a second modulated signal (12b) directed to the second sub-region (16b).