Reference Signal Alignment for Overlapping MU-MIMO Control Channels
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Solution Overview
Problem
In LTE networks, overlapping control channel resource sets limit multi-user multiple-input multiple-output (MU-MIMO) transmission performance due to different initial values of reference signal sequences, preventing orthogonal code division multiplexing and resource reuse among users.
Innovation Solution
A method for obtaining a reference signal that involves determining position offset information based on relative positions of control channel resources and broadcast channels, allowing for the use of the same sequence across overlapping resources, enabling orthogonal MU-MIMO by aligning reference signals for different channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different initial values are used for reference signal sequences in overlapping control channel resource sets, then each channel can be independently configured, but orthogonal code division multiplexing cannot be implemented and MU-MIMO transmission performance is limited
Solution Approach 1:
The patent applies local quality by making the reference signal sequence initialization value position-dependent rather than channel-dependent. Specifically, the initial value is determined by the time-frequency position of the control channel resource set (using formulas involving nPRB and nOFDM), allowing different local positions to use appropriate sequences for their specific function while enabling orthogonal multiplexing in overlapping regions.
Solution Approach 2:
The patent changes the parameter used for sequence initialization from channel-specific identifiers to position-based parameters (physical resource block index and OFDM symbol index). This parameter change enables the same reference signal sequence to be used across different control channels at the same position, facilitating orthogonal code division multiplexing when control channel resource sets overlap.
2Productivity
If control channel resource sets overlap on time-frequency resources, then resource utilization increases, but reference signal sequences cannot be orthogonally multiplexed due to different initial values
Solution Approach 1:
The patent creates equipotentiality by ensuring that control channel resource sets at the same time-frequency position have the same reference signal sequence initialization value regardless of which control channel they belong to. This is achieved by using the physical resource block index and OFDM symbol index in the initialization formula, making all channels at a given position 'equal' in terms of reference signal characteristics, thus enabling orthogonal multiplexing.
3Productivity
If high-quality resources are preferentially allocated to terminal devices, then service quality is improved, but resource scheduling complexity increases due to need for reference signal guidance
Solution Approach 1:
The patent applies self-service by making the reference signal sequence automatically adapt to the control channel resource set position without requiring complex external configuration. The initialization formula using position parameters (nPRB, nOFDM) allows the reference signal to self-configure based on where the control channel is located, reducing the burden on the scheduler while still providing the necessary guidance for high-quality resource allocation.
Data Source
AI summary
This application relates to the mobile communications field, and in particular, to a technology for obtaining a reference signal in a wireless communications system. In a method for obtaining a reference signal, a terminal device obtains position offset information; the terminal device obtains a first sequence based on the position offset information; and the terminal device demodulates, by using the first sequence, a control channel signal carried in a control channel resource set, to obtain downlink control information. In this way, MU-MIMO transmission performance is improved.