Scale-Invariant Symbol Demodulator for MIMO Phase Estimation
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Solution Overview
Problem
In Long Term Evolution (LTE) networks, signaling the magnitude parameter to user equipment (UE) via a Layer 3 radio resource control (RRC) message consumes valuable bandwidth and causes delays, especially for higher order modulation symbols like QAM-16 or QAM-64, which require a magnitude reference for demodulation.
Innovation Solution
A scale-invariant symbol demodulator method that transmits a downlink MIMO signal with only the phase parameter to the UE, allowing the UE to estimate the magnitude parameter, thereby eliminating the need for explicit signaling of the magnitude parameter, which reduces bandwidth consumption and potential delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnitude parameter is signaled to the user equipment via a Layer 3 radio resource control message, then the demodulation accuracy is improved, but the bandwidth consumption increases and delays are caused
Solution Approach 1:
The patent extracts only the necessary phase parameter from the original signaling approach that included both magnitude and phase parameters. By removing the magnitude parameter signaling and allowing the UE to estimate it independently, the solution reduces control message overhead and bandwidth consumption while maintaining demodulation capability through the remaining phase parameter and UE-based magnitude estimation.
Solution Approach 2:
The patent enables the user equipment to self-estimate the magnitude parameter independently without relying on network signaling. The UE uses its own processing capabilities to derive the magnitude information from the received signal, thereby eliminating the need for bandwidth-consuming magnitude parameter signaling while maintaining demodulation accuracy.
2Measurement precision
If the magnitude parameter is signaled to the user equipment via a Layer 3 radio resource control message, then the demodulation accuracy is improved, but the communication delay increases
Solution Approach 1:
The patent enables the user equipment to perform preliminary estimation of the magnitude parameter independently of network signaling. By preparing the magnitude estimate in advance through UE-based estimation rather than waiting for network-provided signaling, the system eliminates the delay associated with Layer 3 message transmission while maintaining the accuracy needed for demodulation.
3Loss of information
If the magnitude parameter is signaled explicitly, then the control information completeness is improved, but the control overhead increases
Solution Approach 1:
The patent extracts only the essential phase parameter from the complete set of modulation parameters (magnitude and phase). By removing the magnitude parameter from control signaling and enabling UE-based estimation, the solution reduces control overhead and message complexity while maintaining sufficient information completeness for accurate demodulation through the combination of signaled phase parameter and estimated magnitude.
Data Source
AI summary
It is possible to improve the spectral efficiency of multi-layer multiple input multiple output (MIMO) transmissions by estimating the magnitude parameter at the receiver side, rather signaling the magnitude parameter from the transmitter to the receiver. In long term evolution (LTE) networks, the user equipment (UE) may estimate the power allocation (Pa) parameter by executing a series of steps. For example, the UE may define a single unknown variable from a received downlink MIMO signal, extend the single unknown scalar variable to a multivariate signal model for multiple channels (N), convert the multivariate signal model to a MIMO configured signal model, and then obtain the Pa parameter from the MIMO configured multivariate signal model.