FBMC Receiver with Alamouti STBC Decoding
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Solution Overview
Problem
FBMC technology faces complexity in applying spatial diversity to MIMO systems due to its intrinsic orthogonality requirements, which complicates interference elimination between symbols, and existing receivers are not adapted for Alamouti block coding, limiting their effectiveness in frequency spread FBMC systems.
Innovation Solution
A method for receiving FBMC signals using Alamouti block coding that works for FS-FBMC receivers, involving sample vectors from multiple channel uses, conjugation of transfer matrices, and spectral despreading with prototype filters to estimate data vectors, allowing for effective decoding in FS-FBMC systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If FBMC modulation is used to achieve better spectral localization, then spectral efficiency is improved, but device complexity increases due to the need for polyphase filter banks
Solution Approach 1:
The patent replaces the time-domain polyphase filter bank implementation with a frequency-domain implementation using IFFT/FFT operations. This substitution transforms the computational approach from mechanical filtering operations to spectral domain transformations, achieving the same spectral localization benefit while simplifying the overall system architecture and reducing implementation complexity.
Solution Approach 2:
The patent changes the domain of operation from time-domain to frequency-domain processing. By performing FBMC operations in the frequency domain using IFFT and FFT, the system maintains the spectral localization properties of FBMC while changing the computational parameters and operations, thereby reducing device complexity.
2Reliability
If Alamouti block coding is applied to FBMC systems for spatial diversity, then reliability is improved, but device complexity increases due to interference elimination requirements
Solution Approach 1:
The patent replaces the complex time-domain interference elimination procedures required for Alamouti block coding with frequency-domain processing. By performing the decoding operations in the frequency domain using IFFT and FFT, the system achieves the same spatial diversity benefit while significantly reducing the computational complexity of interference elimination.
Solution Approach 2:
The patent moves the Alamouti block coding and decoding operations from the time dimension to the frequency dimension. This dimensional transformation allows the system to achieve spatial diversity through frequency-domain processing, reducing the complexity of time-domain interference management while maintaining reliability.
3Quantity of substance
If time-domain FBMC implementation is used, then spectral localization is achieved, but ease of operation deteriorates due to complex polyphase filter networks
Solution Approach 1:
The patent substitutes complex polyphase filter network operations with standard IFFT and FFT operations in the frequency domain. This replacement maintains the spectral localization property of FBMC while using more operationally straightforward and widely-supported computational operations, thereby improving ease of operation.
4Ease of operation
If frequency-domain FBMC implementation is used, then ease of operation is improved, but adaptability to Alamouti coding deteriorates in existing receivers
Solution Approach 1:
The patent designs a frequency-domain FBMC receiver that can handle both standard FBMC signals and Alamouti block-coded signals through a unified processing architecture. The receiver uses IFFT and FFT operations that are universally applicable to both signal types, making the system multi-functional and adaptable without requiring separate processing paths.
Data Source
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Figure 2A~2B
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AI summary
The invention relates to a method for receiving signals emitted by an FBMC transmitter using Alamouti block coding. After baseband demodulation, the received signal is sampled (610), and the sample blocks are subjected to a sliding FFT (630) before being demultiplexed to a first channel (641) during the first use of the channel and to a second channel (642) during a second use of the channel. The vectors received on the first channel are multiplied (681, 683) by a first and second conjugate transfer matrix to provide first and second vectors. The vectors received on the second channel undergo time reversal (652) and complex conjugation (660) and, if necessary, multiplication (670) by an imaginary factor dependent on the block size. The vectors thus obtained are multiplied (682, 684) by a first and a second transfer matrix to provide third and fourth vectors.The first and fourth (second and third vectors) are then combined (691, 692) and the combined vector is filtered and spectrally despreaded (695, 696) to give an estimate of the block transmitted by the transmitter's first (second) antenna on the first use of the channel.