Superposition Transceiver for Microwave Backhaul Spectrum Utilization
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Solution Overview
Problem
Microwave backhaul links face challenges in achieving high spectral efficiency and data transmission capacity due to limited and expensive frequency spectrum, as conventional transceiver apparatuses primarily utilize central portions of the spectral emission mask, neglecting the skirt areas which can violate emission mask requirements.
Innovation Solution
A superposition-based transceiver apparatus that encodes and modulates multiple digital data streams at different rates, using root raised cosine filters and m-ary modulation schemes to combine them into a single aggregate stream that conforms to both central and skirt areas of the spectral emission mask, thereby optimizing spectral utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transceiver apparatuses transmit digital data streams limited to central portions of the spectral emission mask, then spectral emission mask requirements are met, but spectral efficiency and data transmission capacity are compromised
Solution Approach 1:
The patent segments the spectral emission mask into central and skirt areas, and further segments the data transmission into multiple layers. The first layer uses higher-order modulation in the central area, while the second layer uses lower-order modulation in the skirt area, allowing each segment to be optimized independently for both compliance and efficiency
Solution Approach 2:
The patent changes the modulation order parameter across different spectral regions and layers. Higher-order modulation (e.g., 64-QAM, 256-QAM) is applied in the central spectrum, while lower-order modulation (e.g., QPSK, 16-QAM) is applied in the skirt areas, enabling adaptive spectral efficiency while maintaining mask compliance
2Productivity
If the bandwidth of input digital data stream is increased to utilize skirt areas of the spectral emission mask, then data transmission capacity increases, but the resultant spectrum may violate specified spectral emission mask requirements
Solution Approach 1:
The patent implements dynamic spectral allocation where the system adaptively assigns different modulation schemes and power levels to different spectral regions based on channel conditions and requirements. This dynamic approach allows the transceiver to maximize data transmission capacity while continuously maintaining compliance with spectral emission mask requirements
Solution Approach 2:
The patent introduces a vertical dimension to spectral utilization by implementing layered transmission. Instead of treating the spectrum as a single flat resource, the invention creates multiple transmission layers (first layer in central area, second layer in skirt area) that operate simultaneously, effectively adding a dimension to spectral efficiency
Data Source
AI summary
The disclosed systems, structures, and methods are directed to a superposition based transceiver. The configurations presented herein employ a plurality of encoders configured to encode a plurality of input digital data streams, wherein each of the plurality of input digital data streams operates at different data rates, a plurality of modulators configured to modulate the plurality of encoded digital data input streams. In addition, a plurality of transmitter filters configured to perform up-sampling and filtering of the plurality of modulated digital data streams, and a signal mixer configured to combine the plurality of up-sampled and filtered digital data streams into a single aggregate digital data stream in a manner such that the single aggregate digital data stream contains spectral characteristics that substantially conform to both a central area and a skirt area of a unified spectral emission mask, as specified by European Telecommunications Standards Institute (ETSI).