Downlink Control Signaling for Multiuser Constellation Superposition
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Solution Overview
Problem
Current wireless communication systems face limitations in flexibility and efficiency, particularly in multiuser transmission (MUST) operations, where downlink control information (DCI) optimization is challenging due to the need for efficient power allocation and modulation schemes across multiple users.
Innovation Solution
The implementation of constellation superposition techniques in wireless communication systems, specifically using evolved Node B (eNB) and user equipment (UE) to perform symbol level and codeword level superposition coding, allowing for the optimization of DCI formats and power allocation across multiple users, enabling efficient multiuser superposition transmission (MUST) through non-orthogonal multiple access (NOMA).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constellation superposition techniques are implemented to optimize power allocation and modulation schemes, then communication flexibility and efficiency are enhanced, but device complexity and processing requirements increase
Solution Approach 1:
The patent segments the received superposed signal into multiple layers corresponding to different users and modulation schemes. The decoding process is divided into sequential stages where each user's signal is detected and removed in turn, transforming the complex joint decoding problem into manageable sequential processing steps.
Solution Approach 2:
The patent performs preliminary signal processing including superposition coding at the transmitter and preliminary detection at the receiver before final decoding. The receiver first detects the presence and parameters of superposed signals, then proceeds with iterative decoding, preparing the signal in advance to reduce subsequent processing complexity.
2Adaptability or versatility
If non-orthogonal multiple access (NOMA) is used to share time-frequency resources, then resource utilization improves, but interference management becomes more challenging
Solution Approach 1:
The patent applies different power allocation coefficients and modulation schemes to different users based on their channel conditions. Each user experiences a locally optimized signal quality after interference cancellation, with stronger users receiving lower power allocations and weaker users receiving higher power allocations tailored to their specific channel characteristics.
Solution Approach 2:
The patent converts the harmful interference from other users into a beneficial signal through successive interference cancellation. The interfering signals from other users are detected and subtracted from the received signal, transforming what was originally harmful interference into useful information that improves the overall system performance.
3Reliability
If advanced decoding techniques are employed to reduce interference, then signal quality improves, but processing time and computational load increase
Solution Approach 1:
The patent employs iterative decoding where the receiver periodically alternates between detecting different users' signals and canceling their interference. This periodic action continues for a limited number of iterations or until convergence, achieving high signal quality while bounding the processing time through the iterative approach.
Data Source
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AI summary
A method for performing constellation superposition by an evolved Node B (eNB) is described. The method includes determining an admissible data constellation for a second user equipment (UE) based on a data constellation of a first UE. The first UE and the second UE share the same time-frequency resources. The method also includes sending an indication that superposition coded modulation is being employed by the first UE and the second UE. The method further includes sending modulation and coding schemes (MCSs) and/or transmission power percentages used by each of the first UE and the second UE to the other UE.