Superposition Coding Antenna Reduction via Spatial Alignment
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Solution Overview
Problem
In existing superposition coding systems, proximal user equipment requires more antennae than the number of high power data streams to detect, which is not feasible in many cases, especially in multi-user multi-input-multi-output (MIMO) scenarios.
Innovation Solution
The base station adjusts the pre-coding vector of the high power data stream to ensure a product with the effective receiving channel for the low power data stream equals a constant, allowing spatial alignment, and performs superposition coding to enable the proximal user equipment to detect all high power data streams with fewer antennae.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of antennae for proximal user equipment is increased to detect high power data streams, then the detection capability is improved, but the device complexity and cost increase
Solution Approach 1:
The base station changes the parameter of the pre-coding vector to achieve spatial alignment. By adjusting the pre-coding vector such that its product with the effective receiving channel equals a constant, the high power data stream is aligned in space with the low power data stream, enabling detection with fewer antennae
Solution Approach 2:
The patent introduces spatial alignment as a new dimension for signal processing. By aligning signals in the spatial domain through pre-coding vector adjustment, the system transforms the detection problem from requiring more antennae to requiring proper spatial configuration, thereby reducing the number of antennae needed
2Productivity
If superposition coding is used to serve multiple receivers with different channel qualities, then the system throughput is improved, but the interference management becomes more difficult
Solution Approach 1:
The patent applies different pre-coding strategies to different data streams based on their power levels and intended receivers. High power data streams are pre-coded to align spatially with low power streams, creating different local signal characteristics that enable selective detection and elimination at the proximal user equipment
Solution Approach 2:
The base station performs preliminary spatial alignment of high power data streams before transmission by adjusting pre-coding vectors. This preliminary action ensures that when proximal user equipment receives the superposed signal, the high power streams are already positioned in a detectable and eliminable configuration, simplifying the interference cancellation process
Data Source
AI summary
A signal processing method and related equipment are provided, which are used for reducing the number of antennas needed by a proximal user equipment to detect a low power signal. The method comprises: adjusting a pre-coding vector of a high power data stream to allow a product of the pre-coding vector and an effective receiving channel for a low power data stream equal to a constant; performing superposition coding on the low power data stream and the adjusted high power data stream; and sending the superposition-coded data stream to user equipments, wherein the user equipments comprise a user equipment at a center of a cell and a user equipment at an edge of the cell, the high power data stream is an interference while the low power data stream is desirable for the user equipment at the center of the cell.