Rank-Deficient Pilot Mapping Matrix for Phase Tracking
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Solution Overview
Problem
Existing communication systems face challenges in tracking phase errors during training periods, particularly with multiple antennas, leading to degraded communication performance due to phase and frequency offsets.
Innovation Solution
The implementation of a rank-deficient pilot mapping matrix that allows for phase tracking by transmitting and receiving pilot symbols with repeated sets, enabling phase estimation during training periods using cross-correlation or phase delta calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional full-rank pilot mapping matrices are used for MIMO transmission, then channel estimation capability is maintained, but phase tracking during training periods becomes impossible
Solution Approach 1:
The patent changes the rank parameter of the pilot mapping matrix from full-rank to rank-deficient, specifically designing matrices where certain columns are identical. This parameter change enables phase tracking by creating redundant pilot symbols that can be used for phase comparison, while still maintaining sufficient channel estimation capability through the remaining independent columns.
Solution Approach 2:
The patent introduces identical pilot symbol columns in the pilot mapping matrix, where certain columns are exact copies of each other. These copied columns provide redundant reference signals that enable phase tracking by allowing the receiver to compare phases of identical pilots transmitted at different times, thereby detecting phase rotations without requiring full-rank structure.
2Reliability
If rank-deficient pilot mapping matrices with identical pilot symbols are used, then phase tracking is enabled, but channel estimation precision may be degraded
Solution Approach 1:
The patent segments the pilot mapping matrix into distinct functional parts: identical columns dedicated to phase tracking and other columns for channel estimation. This segmentation allows the system to use specific pilot symbols for phase comparison while utilizing other independent pilots for channel estimation, thereby maintaining both functions simultaneously despite the overall rank-deficient structure.
3Measurement precision
If training periods use conventional pilot structures, then channel estimation can be performed, but phase and frequency offsets cannot be tracked
Solution Approach 1:
The patent designs the pilot mapping matrix to serve multiple functions simultaneously: phase tracking, channel estimation, and frequency offset detection. The identical pilot columns provide universal reference signals that enable phase tracking while the overall matrix structure maintains channel estimation capability, making the training period pilots multi-functional rather than dedicated to a single purpose.
Data Source
AI summary
A communication device for enabling phase tracking is described. The communication device includes a processor and instructions stored in memory. The communication device generates a plurality of pilot symbols. The pilot symbols conform to a rank-deficient pilot mapping matrix. The communication device also transmits the plurality of pilot symbols.