Overloaded MIMO Reception with Selective Interference Cancellation
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Solution Overview
Problem
In overloaded MIMO scenarios where the number of transmitting terminals exceeds the number of receive antennas, existing technologies fail to effectively classify and cancel interference signals, leading to increased error rates and deteriorated communication quality.
Innovation Solution
A reception-side apparatus with M receive antennas employs receive diversity processing to classify signals from N transmission-side apparatuses into a desired signal, interference signals to be cancelled, and interference signals not to be cancelled, determining a combination with the highest signal-to-interference ratio (SIR) for demodulation, using methods like MMSE, and reduces the number of patterns to minimize processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If receive diversity processing is performed to cancel interference signals from M-1 transmission-side apparatuses, then communication quality improves, but processing complexity increases when N (number of transmission-side apparatuses) is large
Solution Approach 1:
The patent segments the N transmission-side apparatuses into three categories: the first transmission-side apparatus (desired signal), the M-1 transmission-side apparatuses whose signals are to be cancelled, and the remaining N-M transmission-side apparatuses whose signals are not cancelled. This segmentation enables the receiver to focus computational resources on managing the most critical interference sources while accepting that some interference will remain, thereby reducing overall processing complexity while maintaining communication quality.
Solution Approach 2:
The patent applies partial interference cancellation by selectively cancelling signals from only M-1 transmission-side apparatuses rather than attempting to cancel all N transmission-side apparatuses. This partial action approach acknowledges that complete interference cancellation is computationally prohibitive in overloaded MIMO scenarios, but achieving cancellation for the most significant interferers provides sufficient performance improvement to justify the computational cost.
2Measurement precision
If all N transmission-side apparatuses are processed simultaneously, then complete signal classification is achieved, but the number of patterns to evaluate becomes exponentially large
Solution Approach 1:
The patent divides the N transmission-side apparatuses into distinct groups based on their signal characteristics and cancellation requirements. By segmenting them into the desired signal, cancellable interference signals, and non-cancellable interference signals, the patent dramatically reduces the number of patterns that need to be evaluated from all possible N! permutations to a manageable subset based on the segmented groups.
Solution Approach 2:
The patent applies different processing qualities to different transmission-side apparatuses based on their local characteristics. The first transmission-side apparatus receives full processing attention as the desired signal, the M-1 apparatuses receive cancellation processing for the most significant interferers, and the remaining N-M apparatuses are processed with reduced complexity since their interference is acceptable. This local quality differentiation reduces the overall computational burden while maintaining classification accuracy.
Data Source
AI summary
A reception-side apparatus includes: M receive antennas; and a processor configured to execute a first process of acquiring a first signal received from a first transmission-side apparatus from among signals simultaneously received from the N transmission-side apparatuses by receive diversity processing, and acquiring first data by demodulating and decoding the first signal. In the case of N>M, the processor acquires, for each of all patterns of a combination of a first signal, second signals from M−1 transmission-side apparatuses which are to be cancelled by receive diversity processing and third signals from N−M transmission-side apparatuses which are not to be cancelled by the receive diversity processing, a power ratio of power of the first signal relative to total power of the second and third signals based on a predetermined weight and a channel estimate of each signal, and selects a combination with the largest power ratio from among all the patterns.