Wide-band Virtual Transponder Combining Bandwidths

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Solution Overview

Problem

Current digital direct broadcast systems have limited spectral efficiency due to excessive guard bands, which can be reduced but not efficiently utilized, and suffer from forward error correction (FEC) code latency, hindering the ability to support increased audio, video, and data services.

Innovation Solution

The system combines transponder bandwidths using a wide-band virtual transponder composed of multiple narrow-band physical transponders, allowing for efficient use of non-contiguous or contiguous signal spectrum portions, including guard bands, to increase spectral efficiency and reduce FEC code latency by pooling bandwidths for enhanced symbol rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If guard bands are reduced or eliminated to increase spectral efficiency, then spectral efficiency improves by 21%, but communication performance may be affected

Engineering Contradiction:

Improvespectral efficiencyVSAvoidcommunication performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent combines multiple narrow-band physical transponders into a wide-band virtual transponder, merging fragmented spectrum portions including guard bands into a single logical transmission unit. This allows the system to eliminate traditional guard bands while maintaining communication performance through coordinated FEC encoding across the combined bandwidth.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the bandwidth parameter by transitioning from narrow-band physical transponders to a wide-band virtual transponder configuration. This parameter change enables higher symbol rates and improved spectral efficiency while the FEC coding parameters are adjusted to maintain reliability at the reduced carrier-to-noise ratio.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If FEC code rate is increased to improve throughput, then throughput increases, but FEC code latency increases

Engineering Contradiction:

ImprovethroughputVSAvoidFEC code latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the data stream into multiple elementary streams that are distributed across multiple physical transponders. This segmentation allows the FEC coding to be performed on smaller, more manageable portions of data, reducing the code latency while maintaining high throughput through parallel transmission across multiple transponder channels.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8200149B1Combining transponder bandwidths for source and forward error correction encoding efficiency

Publication Date: 2012.06.12 DIRECTV LLC

AI summary

An apparatus and method for combining transponder bandwidths comprises a wide-band virtual transponder for transmitting a single data stream. The wide-band virtual transponder is comprised of a plurality of narrow-band physical transponders. A plurality of elementary streams are statistically multiplexed to create the single data stream, wherein the single data stream is forward error correction encoded and demultiplexed into a plurality of transponder streams for transmission by the plurality of physical transponders. The physical transponders each use a different portion of a signal spectrum, wherein the different portion may be guard bands or a combination of legacy bands and guard bands. Upon receipt, the transponder streams are multiplexed to recover the single data stream, wherein the recovered single data stream is forward error correction decoded and statistically demultiplexed to recover the plurality of elementary streams.