PTRS-Multiplexed Space-Time Block Coding for Low-PAPR Phase Tracking
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Solution Overview
Problem
Existing transmit diversity schemes for single-carrier waveforms, such as DFT-s-OFDM and SC-OQAM, face challenges in maintaining low Peak-to-Average Power Ratio (PAPR) and accurate phase noise estimation under frequency selective channels and phase noise conditions.
Innovation Solution
A method involving data block partitioning and multiplexing a Phase Tracking Reference Signal (PTRS) with data blocks to create a Space Time Block Code (STBC) signal structure, ensuring each data block is transmitted on specific antenna ports with PTRS blocks at their ends, enabling accurate phase noise estimation and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transmit beamforming is applied to multiple layers of SC-waveform signals, then transmit diversity is achieved, but the PAPR of SC waveform signals increases
Solution Approach 1:
The data stream is segmented into multiple blocks that are processed independently through STBC encoding. Each block is transmitted on a different antenna port, achieving transmit diversity while maintaining the low PAPR property of single-carrier waveforms because each block retains its original PAPR characteristics rather than being combined through linear beamforming operations.
Solution Approach 2:
The patent transitions from time-domain beamforming to a structure that exploits both time and antenna dimensions. By transmitting different encoded blocks on different antenna ports across multiple time slots, the system achieves diversity gain through spatial and temporal separation rather than through linear combination in the time domain, thereby avoiding PAPR increase.
2Reliability
If STBC is applied over two different symbols, then transmit diversity is achieved, but an orphan symbol problem occurs where an even number of symbols is needed
Solution Approach 1:
The transmission is segmented into multiple independent blocks, each of which can be independently encoded and transmitted. This segmentation allows the system to avoid the orphan symbol problem by structuring the transmission in terms of complete blocks rather than requiring pairs of symbols, simplifying the overall symbol structure while maintaining diversity.
Solution Approach 2:
The patent performs preliminary encoding and preparation of data blocks before transmission, organizing them into a structured format that inherently avoids orphan symbols. By pre-structuring the transmission blocks and their mapping to antenna ports, the system eliminates the need for complex post-processing to handle unpaired symbols.
3Reliability
If SFBC is applied in frequency domain over consecutive subcarriers, then transmit diversity is achieved, but the time domain structure of STBC is broken and PAPR increases
Solution Approach 1:
The patent segments the frequency-domain processing into distinct blocks that are independently handled. Each block is processed through STBC encoding in the time domain rather than being combined through frequency-domain operations, preserving the time domain structure and avoiding PAPR increase while still achieving transmit diversity through the blocked structure.
Solution Approach 2:
The patent shifts from frequency-domain processing to a time-domain blocked structure with spatial separation. By transmitting encoded blocks on different antenna ports in the time domain rather than combining them in the frequency domain, the system maintains the time domain structure and low PAPR properties while achieving diversity through spatial and temporal dimensions.
4Ease of operation
If PTRS is repeated in another time instant for phase tracking, then phase tracking is implemented, but phase noise estimation is inferior because conventional phase noise estimation assumes phase noise is the same for the two symbols
Solution Approach 1:
The patent segments the phase tracking reference signals into distinct blocks that are associated with specific data blocks and antenna ports. Each PTRS block is processed independently to estimate phase noise for its corresponding transmission block, avoiding the assumption that phase noise is identical across different time instants and antenna ports, thereby improving estimation accuracy.
Solution Approach 2:
The patent applies local phase noise estimation by associating each PTRS block with its corresponding data block and antenna port. Instead of using a global phase noise assumption, the system performs localized phase noise estimation for each block, accounting for the fact that phase noise varies across different time instants and spatial locations, thereby improving measurement precision.
Data Source
AI summary
Partitioning of data into data blocks and multiplexing a phase tracking reference signal (PTRS) with the data blocks provides a space time block coding (STBC) signal structure between pairs of the data blocks for transmission on respective antenna ports. Signaling that indicates parameters associated with the partitioning and multiplexing is communicated between communication devices in a wireless communication network, and the data blocks multiplexed with the PTRS are transmitted and/or received in the wireless communication network.