FBMC/OQAM Pilot Interference Cancellation via Discrete Precoding
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Solution Overview
Problem
The channel estimation in FBMC/OQAM multicarrier modulation schemes is hindered by intrinsic interference, which is unknown at the receiver, making coherent channel estimation impossible and requiring high power for precoding symbols to cancel interference.
Innovation Solution
Selecting the precoding symbol to force the intrinsic interference at the receiver to a predefined set of discrete values, allowing for flexible power control and reduced transmit power, enabling effective channel estimation by estimating channel coefficients based on known pilot symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precoding symbol is used to cancel intrinsic interference, then channel estimation performance is improved, but transmit power is increased
Solution Approach 1:
The patent changes the parameter of precoding symbol selection from arbitrary values to a predefined set of discrete values. By restricting the precoding symbol to specific discrete values, the system achieves effective intrinsic interference cancellation while controlling and reducing the transmit power requirement, thus resolving the contradiction between channel estimation performance and energy consumption.
2Use of energy by moving object
If intrinsic interference is not cancelled, then transmit power is reduced, but channel estimation becomes impossible
Solution Approach 1:
The patent introduces a precoding symbol as an intermediary element that mediates between the transmitted pilot symbol and the intrinsic interference. By carefully selecting the precoding symbol from a predefined set, it transforms the unknown intrinsic interference into a known quantity, enabling channel estimation while maintaining low transmit power.
3Measurement precision
If precoding symbol power is increased to cancel interference, then channel estimation accuracy is improved, but spectral efficiency is reduced
Solution Approach 1:
The patent applies parameter changes by restricting the precoding symbol to a predefined set of discrete values rather than allowing arbitrary power levels. This constraint enables accurate channel estimation through intrinsic interference cancellation while preventing excessive power consumption, thereby maintaining spectral efficiency.
Data Source
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AI summary
A method for transmitting a multicarrier signal is presented, wherein said signal is of the offset quadrature amplitude modulation OQAM type comprising symbols in the time-frequency space, wherein the symbol is one of a pilot symbol, a precoding symbol, and other symbols; the method being characterized in that the precoding symbol is selected such as to force the intrinsic interference of the pilot symbol, when received by the receiver, to have one value out of a predefined set of discrete values, said set containing at least one element different from zero. Furthermore, a corresponding method for receiving the multicarrier signal transmitted according to the above described method is presented.