Non-deterministic Pilot Symbols for Phase Estimation
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Solution Overview
Problem
Current communication systems face challenges in reducing pilot-related overhead, which limits the gross data rate and requires additional measures for accurate phase estimation, especially in fast phase variations.
Innovation Solution
The use of non-deterministic pilot symbols, which are partially deterministic and partially randomized, allows for effective phase estimation while minimizing data rate overhead by embedding additional information into pilot symbols, such as FEC overhead or network management data, within a predetermined phase range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deterministic pilot symbols are used for phase estimation, then phase estimation accuracy is improved, but pilot-related overhead increases reducing gross data rate
Solution Approach 1:
The patent changes the fundamental parameter of pilot symbols from deterministic to non-deterministic (randomized). This allows the system to embed information bits within the pilot symbols themselves, transforming them from purely overhead elements into dual-purpose signals that perform both phase estimation and information transmission, thereby reducing the overhead ratio and increasing gross data rate while maintaining phase estimation capability through the randomized structure
Solution Approach 2:
The non-deterministic pilot symbols serve multiple functions simultaneously: they provide phase estimation reference, carry information bits (including FEC overhead and network management data), and maintain synchronization. This multi-functionality eliminates the need for separate overhead channels, resolving the contradiction between phase estimation accuracy and data rate by making the pilot symbols universally useful for both purposes
2Reliability
If pilot spacing is reduced to maintain accurate phase estimation in fast phase variations, then phase estimation reliability is improved, but pilot overhead increases reducing information transmission efficiency
Solution Approach 1:
By changing pilots from deterministic to non-deterministic, the patent enables information bits to be embedded within the pilot symbols. This allows the system to maintain larger pilot spacing (reducing overhead) while still achieving reliable phase estimation, because the randomized structure provides sufficient statistical properties for accurate phase recovery even with fewer pilots
3Productivity
If superimposed pilots with low energy are used to avoid data rate reduction, then data rate is maintained, but receiver signal-to-noise ratio decreases
Solution Approach 1:
Instead of superimposing low-energy pilots onto data symbols (which degrades SNR), the patent inverts the approach by making the pilots themselves carry the information. The non-deterministic pilot symbols are transmitted with full energy, and the information is extracted from their randomized structure rather than being superimposed, thereby maintaining both high data rate and high receiver SNR
Data Source
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AI summary
Embodiments relate to a transmitter (71) for transmitting a signal comprising data symbols and non-deterministic pilot symbols. The transmitter includes a mapper (712) operable to map one or more non-deterministic bits (u) to a non-deterministic pilot symbol having a pilot symbol phase in a predetermined pilot symbol phase range; and a pilot symbol inserter (115) operable to insert the pilot symbol into a stream of data symbols. Further, embodiments also relate to a corresponding receiver (73) for receiving a stream of data and pilot symbols. The receiver includes a phase estimator (737) operable to estimate a phase of a transmission channel based on a comparison of a received symbol corresponding to a pilot symbol position with a hypothetical pilot symbol, the hypothetical pilot symbol corresponding to one or more hypothetical non-deterministic bits (u) and having a pilot symbol phase in a predetermined pilot symbol phase range.