SCMA Codebook Design for Higher Coding Rates and Decoding Accuracy
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Solution Overview
Problem
Existing wireless communication systems, such as LTE, face challenges in achieving higher coding rates to meet the growing demands of mobile broadband access, and existing multiple-access technologies like CDMA may not provide sufficient encoding for current wireless networks.
Innovation Solution
A method and apparatus for multilayer transmission in wireless networks involving the generation, mapping, and combining of binary data bits to maximize code word distances within each layer, using sparse code multiple access (SCMA) techniques to achieve multi-dimensional coded modulation for non-orthogonal multiple access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multiple-access technologies like CDMA are used, then system implementation is straightforward, but coding rates are insufficient to meet growing mobile broadband demands
Solution Approach 1:
The patent transitions from traditional single-dimensional spreading codes to multi-dimensional codebooks where codes are organized across multiple dimensions (e.g., different spreading factors, orthogonal cover codes, and cyclic shifts). This dimensional expansion enables higher coding rates by providing more code resources without proportionally increasing system complexity.
Solution Approach 2:
The codebook is segmented into multiple layers or groups, each serving different coding rate requirements. This segmentation allows the system to select appropriate code segments based on traffic conditions, achieving high coding rates when needed while maintaining manageable complexity through modular code organization.
2Productivity
If higher coding rates are implemented to meet mobile broadband demands, then network capacity increases, but system complexity and implementation difficulty increase
Solution Approach 1:
The system employs dynamic codebook selection where the codebook structure and parameters are adapted based on channel conditions, traffic load, and quality of service requirements. This dynamics allows the system to optimize network capacity while managing complexity by using simpler codebooks when conditions permit and more complex ones only when necessary.
Solution Approach 2:
The patent utilizes parameter changes in codebook design, such as varying spreading factors, code lengths, and orthogonality constraints, to achieve different coding rates. By changing these parameters rather than fundamentally altering the system architecture, the patent increases network capacity while controlling implementation complexity.
3Reliability
If code words are mapped to maximize distance within each layer, then decoding accuracy improves, but mapping complexity increases
Solution Approach 1:
The codebooks are pre-designed and pre-optimized during system setup to maximize the minimum distance between code words within each layer. This preliminary action eliminates the need for complex real-time optimization during transmission, achieving high decoding accuracy while keeping runtime mapping complexity manageable through pre-computed optimal mappings.
Data Source
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AI summary
The present disclosure describes a method, an apparatus, and a computer readable medium for a multilayer transmission in a wireless network. For example, the method may include generating a group of binary data bits for resources of each layer of a plurality of layers, mapping the group of binary data bits of each layer of the plurality of layers to respective code words in a signal constellation, combining the code words, and transmitting the combined code word to receiver in the wireless network. As such, the multilayer transmission in a wireless network is achieved.