FBMC Resource Block Interference Elimination via Cyclic Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Filter bank multicarrier (FBMC) systems face interference issues between resource blocks due to frequency asynchronous users, leading to inter-carrier interference (ICI) and increased complexity, especially in 5G systems with higher Doppler shifts and oscillator inaccuracies, which existing methods fail to adequately address without compromising spectral efficiency.
Innovation Solution
A new frequency asynchronous multiuser FBMC scheme that performs discrete Fourier transform (DFT) on data symbols, followed by a cyclic shift operation to place a small magnitude element at the edge of resource blocks, minimizing interference between adjacent blocks, and compensates for cyclic shifts during demodulation to reduce ICI without requiring additional guard subcarriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FBMC transmission technology is used to achieve higher frequency efficiency and eliminate cyclic prefix, then frequency efficiency is improved, but interference between resource blocks increases due to frequency asynchronous users
Solution Approach 1:
The patent applies preliminary action by performing DFT spreading on data symbols before FBMC modulation, and cyclic shifting the DFT-spread symbols to position minimum magnitude elements at edge subcarriers. This pre-processing arrangement minimizes interference between adjacent resource blocks before transmission occurs, resolving the contradiction by preparing the signal structure in advance to prevent interference while maintaining frequency efficiency
Solution Approach 2:
The patent changes the parameter arrangement of DFT-spread symbols by cyclic shifting them to different positions, specifically placing minimum magnitude elements at edge subcarriers. This parameter change in symbol arrangement reduces inter-carrier interference between resource blocks while preserving the frequency efficiency benefits of FBMC transmission
2Object-generated harmful factors
If DFT-spread data symbols undergo cyclic shift operation to minimize interference, then inter-user ICI is reduced, but computational complexity increases
Solution Approach 1:
The cyclic shift operation is performed as a preliminary action during transmission, and the corresponding inverse cyclic shift is performed during reception. This pre-and post-processing approach minimizes inter-user ICI by arranging symbols optimally before transmission and restoring them after reception, managing computational complexity through structured pre-computation
3Reliability
If cyclic shift operation is performed on DFT-spread data symbols, then oscillator inaccuracy and Doppler shift tolerance increase, but signal processing complexity increases
Solution Approach 1:
The cyclic shift operation is performed as a preliminary action that pre-arranges DFT-spread symbols to position minimum magnitude elements at edge subcarriers. This pre-arrangement creates signal structure that is inherently more tolerant of oscillator inaccuracy and Doppler shift, as the minimum magnitude elements at edges reduce interference even when frequency offsets occur
Solution Approach 2:
The patent changes the parameter arrangement of DFT-spread symbols through cyclic shifting, transforming the signal from a conventional arrangement to one where minimum magnitude elements are positioned at edge subcarriers. This parameter change creates robustness against oscillator inaccuracy and Doppler shift by ensuring that edge subcarriers, which are most sensitive to frequency offsets, contain the least significant elements
Data Source
AI summary
The present disclosure relates to a method and an apparatus for reducing or eliminating interferences between resource blocks in a transmitter and/or a receiver of a filter bank multicarrier system is provided. According to at least one embodiment, the method comprises performing discrete Fourier transform (DFT) on a data symbol vector to be transmitted thereby generating a DFT-spread data symbol vector, performing a cyclic shift operation on the DFT-spread data symbol vector to arrange a small magnitude element of the DFT-spread data symbol vector at an edge of a resource block allocated to the DFT-spread data symbol vector, and performing filter bank multicarrier (FBMC) modulation on a cyclically shifted DFT-spread data symbol vector.