Precoded Data Stream Optimization for Multi-User MIMO Transmitters
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Solution Overview
Problem
Wireless communication systems face challenges in optimizing data transmission in multi-user MIMO environments, where interference and noise affect the signal-to-interference-plus-noise ratio (SINR) across receivers, leading to suboptimal performance and fairness issues among data streams.
Innovation Solution
A method is introduced to determine a precoded data stream by calculating the SINR and channel gain for each receiver, maximizing a utility function that is proportional to SINR at low values and asymptotically constant at high values, using linear and non-linear precoding techniques, and optimizing the transmit covariance matrix to improve system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple-input multiple-output (MIMO) techniques are used with multi-output transmitters and receivers, then system performance is enhanced, but interference and noise affect the signal-to-interference-plus-noise ratio (SINR) across receivers, leading to suboptimal performance and fairness issues among data streams
Solution Approach 1:
The patent applies preliminary action by determining a precoded data stream before transmission. The system calculates SINR and channel gain for each receiver, then performs precoding operations in advance to maximize the sum of utility functions. This preliminary processing of data streams through precoding matrices resolves interference issues before the actual transmission occurs, improving reliability while managing harmful interference effects.
2Ease of operation
If precoding is applied to maximize sum of utility functions, then fairness among data streams is achieved, but device complexity increases due to SINR calculation and optimization requirements
Solution Approach 1:
The system implements self-service by having each receiver report its own SINR and channel gain information back to the transmitter. The transmitter then uses this self-reported information to automatically determine the precoded data stream that maximizes the sum of utility functions. This self-service mechanism achieves fairness among data streams while reducing the complexity of centralized control and optimization calculations.
3Productivity
If utility functions are designed to be proportional to SINR at low values and asymptotically constant at high values, then sum rate of data transmission is enhanced, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent introduces an intermediary approach by using utility functions as a mathematical mediator between SINR measurements and transmission rate optimization. The utility function serves as an intermediate representation that transforms complex SINR relationships into a form that can be easily maximized through precoding optimization. This intermediary function simplifies the detection and measurement process while enhancing the sum rate of data transmission.
Data Source
AI summary
In accordance with an embodiment, a method of operating a multi-output wireless transmitter includes determining a precoded data stream based on input data, where the determining includes determining a signal to interference plus noise ratio (SINR) of a plurality of receivers, determining a channel gain to each of the plurality of receivers, and maximizing a sum of utility functions, wherein each utility function is proportional to the SINR of each of the plurality of receivers at low SINR values and asymptotically approaches a constant value at high SINR values. The precoded data stream is transmitted on the multi-output wireless transmitter.