Polar Code Frozen Bit Patterns for NOMA Uplink Interference
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Solution Overview
Problem
Current non-orthogonal multiple access (NOMA) methods in wireless communication systems do not effectively utilize frozen bit locations of polar codes for improving data transfer performance in uplink communication scenarios, particularly for low-cost and energy-saving devices that send sparse and small packets, and lack efficient grant-free and contention-based communication solutions.
Innovation Solution
The proposed solution involves a transmitter and receiver system that uses a pattern generating module to create binary-valued pattern sequences for polar encoding, a channel encoding module for polar encoding, a symbol mapping module, and a symbol transmitting module to generate transmitted signals, along with a signal reception module, baseband conversion, and a signal detection module using interference-cancellation multi-user detection and polar decoding to separate user data in uplink radio channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal multiple access (NOMA) schemes are used to increase system capacity and support more users, then the number of supported users increases, but multi-user interference increases and signal separation becomes more difficult
Solution Approach 1:
The patent segments the code domain by dividing the codeword into information bits and frozen bits, with frozen bits further segmented into pattern bits and remaining frozen bits. This segmentation allows different users to be assigned distinct binary-valued patterns in the frozen bit locations, enabling signal separation through code domain division while maintaining non-orthogonal superposition for capacity enhancement
Solution Approach 2:
The patent applies local quality by assigning user-specific binary-valued patterns to specific frozen bit locations while keeping other frozen bits and information bits distinct. This localized differentiation in the code domain enables the receiver to separate user signals by exploiting the unique pattern characteristics at frozen bit positions without requiring complete orthogonality across the entire signal
2Measurement precision
If user-specific signatures or patterns are introduced to distinguish between users in NOMA, then user separation capability improves, but device complexity and processing overhead increase
Solution Approach 1:
The patent changes the parameter space by utilizing the frozen bit locations in the code domain, which are traditionally fixed or predetermined, to carry user-specific binary-valued patterns. This parameter change allows user separation without requiring complex time-varying or frequency-varying signatures, maintaining relatively simple device implementation while achieving effective user distinction through code domain pattern differentiation
3Measurement precision
If orthogonal multiple access (OMA) schemes are used to simplify signal separation and reduce interference, then signal detection accuracy improves, but the number of supported users is limited by the number of orthogonal resources
Solution Approach 1:
The patent transitions from traditional time-frequency domain orthogonal resources to the code domain by embedding user-specific information in the frozen bit patterns of polar codes. This dimensional change to the code domain allows multiple users to share the same time-frequency resources non-orthogonally while maintaining separability through unique binary-valued patterns, effectively increasing the number of supported users beyond orthogonal resource limitations
Data Source
AI summary
An uplink multiple access method based on the user-specific frozen bit patterns of polar codes assigned to users and relevant transmitter-receiver embodiments. The method includes encoding the information bits with a polar encoder by using the binary-valued, user-specific frozen bit patterns in frozen bit locations during encoding operation. The method further includes mapping of coded bits with symbols to be transmitted and baseband-to-RF processing performed on the symbol sequence. The generated signals of each user are transmitted by using the same time-frequency resources. The method further includes to receive the superposed signal of multiple users transmitted by means of relevant uplink radio channels. The method further includes an RF-to-baseband conversion on the received signal and detecting and decoding each user data by using an interference cancellation multiuser detector and a polar decoder that uses binary-valued pattern sequences assigned to the users in the frozen bit locations.