GFDM Transmitter Time-Frequency Matrix Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems, such as OFDM, face challenges in minimizing out-of-band leakage, adapting to varying channel conditions, and efficiently utilizing frequency resources, particularly in cognitive radio and machine-to-machine communication scenarios, where flexibility and energy efficiency are crucial.
Innovation Solution
The proposed solution involves a generalized frequency division multiplexing (GFDM) system that uses multi-dimensional Fourier processing to transform data symbols into the time-frequency domain, allowing for individual carrier modulation and pulse shaping, which reduces inter-symbol interference and enables efficient use of frequency resources by spreading information across multiple elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM is used to divide frequency band into multiple carriers, then frequency diversity can be exploited and implementation efficiency is improved, but out-of-band leakage occurs and transmission resources are wasted due to guard bands
Solution Approach 1:
The patent transitions from traditional one-dimensional frequency domain processing to two-dimensional time-frequency domain processing. By applying DFT in the time domain and FFT in the frequency domain simultaneously, the system achieves flexible resource allocation and reduced out-of-band leakage through multi-dimensional signal manipulation
Solution Approach 2:
The system dynamically adjusts modulation parameters, filter characteristics, and resource allocation across time and frequency dimensions. By changing parameters such as DFT size, FFT size, and filter coefficients adaptively, the system optimizes spectral efficiency while minimizing out-of-band radiation
2Object-generated harmful factors
If guard bands are inserted to separate adjacent frequency bands, then out-of-band leakage is reduced, but transmission resources remain unused
Solution Approach 1:
Instead of permanently allocating guard bands as unused resources, the system recovers these frequency resources by applying time-domain filtering and DFT-based modulation. The filter design allows adjacent carriers to be closer while maintaining spectral separation, thereby recovering previously wasted guard band resources for data transmission
Solution Approach 2:
The patent introduces digital filters and DFT-based modulation as intermediary mechanisms between adjacent carriers. These intermediaries provide spectral separation without requiring guard bands, enabling efficient use of frequency resources while controlling out-of-band leakage
3Adaptability or versatility
If individual carrier modulation is applied in GFDM, then flexibility in frequency usage is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple processing functions into unified operations: DFT-based modulation merges frequency shifting and modulation, while time-domain filtering combines spectral shaping and interference mitigation. This merging reduces the number of separate processing stages and simplifies the overall system architecture
Solution Approach 2:
The DFT-FFT based modulation scheme serves multiple functions simultaneously: it performs frequency shifting, modulation, and spectral shaping in a unified framework. This multi-functional approach eliminates the need for separate processing blocks for each function, thereby reducing device complexity
4Productivity
If DFT and FFT processing is applied for multi-carrier modulation, then spectral efficiency is improved, but computational complexity increases
Solution Approach 1:
The system performs DFT-based pre-processing of data symbols before FFT modulation. This preliminary action organizes the data in a way that enables efficient FFT processing and reduces the computational burden during the main modulation stage, thereby optimizing the overall computational complexity
Data Source
Figure 1a~1b
Figure 2a~2
Figure 3a~3
AI summary
A method and corresponding devices for processing and transmitting information are described. A sequence of binary signals is mapped to symbols that forms a two-dimensional matrix of symbols in one of the frequency-time or time-time or time-frequency or frequency-frequency domain and which may be filtered in that domain. Selecting the diagonal elements of said matrix forms a transmit vector.