Non-Uniform Modulation Framing for Adaptive Demodulation
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Solution Overview
Problem
Conventional modulation technologies, such as QAM, are inadequate in achieving optimal channel capacity and bit error rate performance due to input amplitude constraints and varying noise distributions, particularly in applications like virtual reality, ultra-high-definition video, and the Internet of Vehicles, which require improved communication rates and power efficiency.
Innovation Solution
The implementation of probability non-uniform modulation, where constellation symbols have different probabilities and spacings, utilizing a Maximum a Posteriori estimation algorithm to achieve better shaping gain and robustness against interference, with a data transmission method and apparatus that maps bit streams to constellation symbols with varying probabilities, enabling flexible modulation orders and improved frequency band efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional modulation technologies (e.g., QAM) are used with uniform constellation symbol probability, then the modulation scheme is simple and easy to implement, but the channel capacity is insufficient and bit error rate performance is poor when there are input amplitude constraints or different noise distributions
Solution Approach 1:
The patent applies local quality by assigning different probabilities to different constellation symbols based on their specific characteristics and positions. Symbols that are more robust to noise or less likely to cause errors are assigned higher probabilities, while vulnerable symbols receive lower probabilities. This localized probability assignment optimizes the overall system reliability without requiring complete redesign of the modulation framework.
Solution Approach 2:
The patent changes the probability parameter of constellation symbols from uniform to non-uniform distribution. By adjusting the probability values of different symbols according to noise distribution characteristics and input amplitude constraints, the system achieves better bit error rate performance. The probability parameters are optimized to match the specific channel conditions, transforming a static uniform probability model into a dynamic adaptive one.
2Reliability
If conventional modulation technologies are used without considering noise distribution and power limitation, then the modulation design is straightforward, but the channel capacity is insufficient under input amplitude constraints
Solution Approach 1:
The patent optimizes the probability parameters of constellation symbols to achieve maximum channel capacity under input amplitude constraints. By calculating and adjusting the probability values based on the specific noise distribution and power limitations, the system extracts more information from the same transmission resources, thereby increasing channel capacity without requiring additional transmission power or bandwidth.
Solution Approach 2:
The patent employs feedback mechanisms where the receiver estimates the channel conditions and noise distribution, then feeds this information back to the transmitter. The transmitter uses this feedback to adjust the constellation symbol probabilities adaptively, ensuring optimal channel capacity utilization. This closed-loop system allows the modulation scheme to respond to changing channel conditions and maintain high efficiency.
3Productivity
If probability non-uniform modulation is implemented with different constellation symbol probabilities, then transmission efficiency and channel capacity are improved, but the modulation scheme becomes more complex requiring Maximum a Posteriori estimation algorithms
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal probability values for each constellation symbol before transmission. These pre-computed probabilities are based on anticipated channel conditions and noise characteristics. During actual transmission, the system simply looks up and applies these pre-determined probabilities, avoiding complex real-time calculations at the transmitter and reducing computational burden during demodulation.
Solution Approach 2:
The patent introduces an intermediary probability distribution layer between the binary data input and the constellation symbol output. This intermediary layer translates uniform probability binary data into non-uniform probability constellation symbols according to pre-determined mapping rules. The intermediary mapping table or function simplifies the overall process by decoupling the complexity of probability optimization from the real-time modulation and demodulation operations.
Data Source
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AI summary
This application discloses a data transmission method and apparatus based on probability non-uniform modulation, to improve transmission efficiency of data on which probability non-uniform modulation is performed. The method includes: generating, by a transmit end, a physical layer data frame, where the physical layer data frame includes data on which probability non-uniform modulation is performed and indication information, the indication information is used to indicate demodulation parameters for performing probability non-uniform demodulation on the data, the demodulation parameters include a modulation scheme for probability non-uniform modulation and a modulation order for probability non-uniform modulation, and the demodulation parameters further include at least one of the following: a probability of each constellation symbol on which probability non-uniform modulation is performed, and a mapping relationship between each constellation symbol on which probability non-uniform modulation is performed and a bit stream; sending, by the transmit end, the physical layer data frame to a receive end; receiving, by the receive end, the physical layer data frame; determining, by the receive end, the demodulation parameters based on the indication information; and performing, by the receive end, probability non-uniform demodulation on the data based on the demodulation parameters. This application relates to the field of communications technologies.