MIMO-OFDM FFT Scheduling to Cut Operator Count and Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MIMO-OFDM systems require a large number of FFT and IFFT operators, leading to increased hardware complexity and data process delays, especially in receiving terminals, due to the need for multiple operators for each antenna, and increasing operation speed is limited by complexity and hardware constraints.
Innovation Solution
Designing an operation schedule that allows a single FFT/IFFT operator to perform both FFT and IFFT operations at higher speeds than data transmission, with symbols arranged in schedules to minimize the number of operators needed and reduce delays by overlapping processing times in TDD systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple FFT operators are provided for each antenna in MIMO-OFDM receiving terminal, then the receiving terminal can perform proper modulation and demodulation operations, but the hardware complexity and data process delays increase significantly
Solution Approach 1:
The patent applies multi-functionality by enabling a single FFT operator to serve multiple antennas through time-division multiplexing. The FFT operator performs FFT operations for different antennas in sequential time slots, allowing one hardware unit to replace what would traditionally require multiple parallel operators. This reduces hardware complexity while maintaining the ability to perform proper modulation and demodulation for all antennas.
Solution Approach 2:
The patent transitions from a spatial dimension (multiple parallel FFT operators for each antenna) to a time dimension (sequential FFT operations for different antennas). By scheduling FFT operations in time slots rather than requiring simultaneous parallel operations, the system achieves the same functional capability with fewer hardware resources, directly reducing device complexity.
2Quantity of substance
If the operation speed of FFT operator is increased to reduce the number of operators, then fewer FFT operators are needed, but the structure becomes more complex and hardware constraints limit further speed increases
Solution Approach 1:
The patent introduces dynamic scheduling mechanisms that adapt the operation timing of FFT operators based on data transmission requirements. By dynamically allocating time slots and adjusting operation speeds according to actual needs, the system can reduce the number of operators without requiring permanent high-speed complex structures. The scheduling flexibility allows simpler operator designs to achieve the same throughput.
3Speed
If FFT operators operate at higher speeds, then data processing can be completed faster, but the operation speed is limited by hardware constraints and structural complexity
Solution Approach 1:
The patent implements preliminary scheduling actions where the controller pre-calculates and assigns time slots for FFT operations before actual processing begins. This preliminary arrangement optimizes the execution sequence and allows operators to operate at optimal speeds without waiting for data, thereby increasing effective processing speed. The scheduling overhead is minimal compared to the processing time saved.
Data Source
AI summary
The present invention provides a method for designing operation schedules of a fast Fourier transform (FFT) and a multiple input multiple output orthogonal frequency division multiplexing modem (MIMO-OFDM modem) thereof. According to the present invention, an operation speed of an FFT operator is set up, a receiving symbol is arranged in an OFDM symbol duration in an FFT after receiving the symbol, a transmitting symbol is arranged in an OFDM symbol duration in the FFT schedule before transmitting the symbol, a transmitting/receiving symbol which has the same timing is inserted into an idle symbol duration of the FFT schedule, an FFT schedule which is good to be deleted is deleted, and symbols of the deleted FFT schedule are re-arranged in order to not have an error occur in transmitting/receiving timing.