Layered Broadcast Signal Frames for Flexible Power-Domain Multiplexing
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Solution Overview
Problem
Existing broadcast signal multiplexing technologies, such as TDM and FDM, lack the flexibility and performance required for next-generation broadcasting systems, and do not efficiently utilize time and frequency resources for multiple services.
Innovation Solution
A broadcast signal frame structure that combines core and enhanced layer signals at different power levels, using a preamble to signal start positions and time interleaver information, and includes a power normalizer to adjust signal power levels, enabling efficient multiplexing and demultiplexing of signals across multiple layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TDM or FDM is used for multiplexing, then multiple services can be transmitted, but resource utilization efficiency and system flexibility are insufficient
Solution Approach 1:
The transmission signal is segmented into multiple layers (first layer and second layer) with different power levels. Each layer can carry different services independently, allowing flexible resource allocation. The first layer uses higher power for robust transmission of critical services, while the second layer uses lower power for additional services, achieving both high resource utilization and system flexibility.
Solution Approach 2:
The patent introduces a power level dimension to traditional multiplexing schemes. Instead of only time (TDM) or frequency (FDM) division, signals are now divided across power levels, creating a three-dimensional resource allocation space (time-frequency-power). This enables services to be multiplexed not just in time or frequency but also in power domain, dramatically improving resource utilization efficiency while maintaining flexibility.
2Productivity
If layered division multiplexing is implemented, then resource utilization and flexibility are improved, but signal processing complexity increases
Solution Approach 1:
A power normalization process is introduced as an intermediary step between layer combination and OFDM modulation. The power normalizer adjusts the combined signal to a standardized power level, simplifying subsequent processing stages. This intermediary operation prevents power-related complications in later signal processing while maintaining the benefits of layered multiplexing.
Solution Approach 2:
The patent systematically manages power level parameters throughout the signal processing chain. By normalizing power levels at critical points (after combination, before modulation), the system maintains parameter consistency and avoids exponential complexity growth. This parameter management approach allows layered multiplexing to be implemented with manageable processing complexity.
3Productivity
If multiple services share the same time and frequency resources, then resource utilization reaches 100%, but signal interference and demultiplexing difficulty increase
Solution Approach 1:
Different power levels are assigned to different service layers, creating local quality differences that facilitate demultiplexing. The first layer uses higher power for services requiring robust reception, while the second layer uses lower power for services that can tolerate reduced signal strength. This local quality differentiation allows receivers to reliably demultiplex services by filtering based on power level characteristics.
Solution Approach 2:
Power normalization is performed in advance before OFDM modulation and transmission. By pre-adjusting the power levels of combined layers and normalizing the overall signal, the system eliminates power-related interference issues that would complicate demultiplexing. This preliminary power management ensures that receivers can cleanly separate services without dealing with power imbalance complications.
Data Source
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AI summary
An apparatus and method for broadcast signal frame using layered division multiplexing are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling, start position information of Physical Layer Pipes (PLPs) and time interleaver information shared by the core layer signal and the enhanced layer signal.