Data-Modulated Pilot Symbols for Phase Detection in Wireless Systems
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Solution Overview
Problem
Wireless communication systems face challenges in maintaining data throughput due to phase noise and the need for pilot symbols, which increase the coding rate and reduce the number of symbols available for data, leading to incorrect hard decisions and decreased performance.
Innovation Solution
Implementing data modulated pilot symbols with a more reliable modulation and coding scheme, allowing adaptive demodulation switching and generating a priori log-likelihood ratios to improve decoding accuracy without increasing the coding rate, by using a combination of first and second modulation and coding schemes for data and pilot symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pilot symbols are inserted into the data stream, then phase detection accuracy is improved, but the coding rate increases and data throughput decreases
Solution Approach 1:
Data symbols are designed to serve dual purposes: carrying information data and functioning as pilot symbols for phase detection. The receiver identifies certain data symbols as pilot symbols based on their position in the received signal, allowing the same symbol to perform both data transmission and phase reference functions simultaneously.
Solution Approach 2:
The invention merges the previously separate functions of data symbols and pilot symbols into a single unified approach. Instead of inserting dedicated pilot symbols separate from data symbols, the system combines these functions by using data symbols themselves as the basis for phase detection, eliminating the need for separate pilot symbol resources.
2Reliability
If pilot symbols are inserted to improve hard decisions, then decoding accuracy is improved, but the number of data symbols available decreases
Solution Approach 1:
Data symbols serve multiple functions simultaneously: they carry information data and act as pilot symbols for phase detection. This multi-functionality ensures that no additional symbols are needed for phase reference, maintaining the total number of data symbols while improving decoding accuracy through better phase detection.
Solution Approach 2:
The data symbols themselves provide the phase reference information needed for accurate detection. Instead of relying on separate pilot symbols, the system uses the data symbols' own characteristics and positions to generate phase detection references, making the system self-sufficient and eliminating the need for external pilot resources.
3Productivity
If coding rate is increased to maintain data throughput when using pilot symbols, then data throughput is maintained, but the complexity of the communication system increases
Solution Approach 1:
By making data symbols serve dual purposes as both information carriers and phase references, the system eliminates the need for separate pilot symbol insertion and the associated coding rate adjustments. This maintains data throughput without requiring increased coding rates or additional system complexity for pilot management.
Solution Approach 2:
The invention extracts the phase detection function from the separate pilot symbol structure and integrates it directly into the data symbol processing. This extraction eliminates the need for additional pilot symbol handling, coding rate calculations, and resource allocation mechanisms, thereby reducing overall system complexity while maintaining throughput.
Data Source
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AI summary
Methods, systems, and devices are described for mitigating an unwanted increase in a coding rate of a wireless communication signal. A plurality of symbols including a transmitted codeword is received. The plurality of symbols including a first group of data symbols with a first modulation and coding scheme and a second group of data modulated pilot symbols with a second modulation and coding scheme. Applicable demodulation schemes are adaptively switched for each group of the plurality of symbols. The second group of data modulated pilot symbols are used in lieu of pilot symbols. The second modulation and coding scheme is a more reliable modulation and coding scheme than the first modulation and coding scheme.