K-bit Enumerative Sphere Shaping for Constellation Complexity
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Solution Overview
Problem
Current data communication systems face inefficiencies in utilizing channel capacity due to uniform signaling schemes, leading to a gap between the Shannon limit and achievable information rates, with high computational and storage complexities in enumerative sphere shaping for large constellations.
Innovation Solution
Implementing a modified k-bit enumerative sphere shaping that prescribes a subset of amplitude bits and uniformly distributes the remaining bits to reduce computational load and storage requirements, while maintaining significant shaping gain, thereby decreasing the required SNR and enabling rate adaptivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enumerative sphere shaping is applied to large constellations, then shaping gain is improved, but computational complexity and storage requirements increase significantly
Solution Approach 1:
The patent segments the amplitude bits into two distinct groups: shaped amplitude bits that are processed through enumerative sphere shaping, and uniform amplitude bits that are distributed uniformly. This segmentation allows the system to apply shaping only to the necessary subset of bits, reducing computational complexity and storage requirements while maintaining significant shaping gain.
2Device complexity
If uniform signaling schemes are used, then device complexity is reduced, but the gap to Shannon capacity increases
Solution Approach 1:
The patent applies local quality by using uniform distribution for some amplitude bits (where simplicity is adequate) and shaped distribution for other amplitude bits (where performance gain is needed). This localized application of different distribution strategies optimizes the balance between complexity and performance, achieving better Shannon capacity utilization without uniformly increasing system complexity.
Data Source
AI summary
A method for k-bit Enumerative Sphere Shaping (ESS) of multidimensional constellations includes converting a first set of a plurality of uniformly distributed data bits from a serial data bit stream to a first unsigned amplitude sequence comprising a plurality of amplitudes bounded by a spherical constellation of maximum energy levels of a plurality of energy levels, wherein the first unsigned amplitude sequence has a Gaussian distribution and each of the energy levels is determined by a respective one of the amplitudes in the amplitude sequence. The first unsigned amplitude sequence is converted to a first shaped data bit sequence. The first shaped data bit sequence is combined with a second set of a one or more uniformly distributed data bits from the serial data bit stream to form a combined data stream. The combined data stream is mapped to a combined amplitude stream.