OFDM Signal Generation via Segmentation and Bandwidth Restriction
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Solution Overview
Problem
In OFDM-based wireless communication systems, existing techniques struggle to specify signals in the frequency domain when sequences occupy a non-integer number of symbol periods, leading to inefficiencies in signal transmission and reception.
Innovation Solution
A method is introduced where a wireless device generates an approximated signal by segmenting the original signal into symbol period-sized segments, applying transform operations like FFT and IFFT, and appending cyclic prefixes to ensure bandwidth restriction and accurate frequency domain representation, allowing for effective transmission and reception even with non-integer sequence lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If long sequences spanning multiple symbol periods are used, then communication flexibility and bandwidth utilization are improved, but the ability to specify signals in the frequency domain deteriorates when sequences occupy non-integer symbol periods
Solution Approach 1:
The patent segments the original signal into multiple segments, each corresponding to one symbol period. This allows the system to handle long sequences that span non-integer symbol periods by processing them in discrete, manageable units. Each segment can be independently transformed and transmitted, resolving the contradiction between using long flexible sequences and maintaining frequency domain specification capability.
Solution Approach 2:
The patent introduces an intermediary processing step involving FFT transformation, bandwidth restriction, and IFFT transformation. This intermediary process acts as a bridge between the time-domain segmented signals and the frequency-domain representation, enabling accurate frequency domain specification even when original sequences span non-integer symbol periods.
2Productivity
If sequences occupy non-integer symbol periods, then bandwidth utilization is improved, but signal specification in frequency domain becomes impossible
Solution Approach 1:
By segmenting the signal into symbol period-aligned units, the patent enables processing of sequences that originally occupied non-integer symbol periods. This segmentation allows the system to maintain high bandwidth utilization while making the signal generation process feasible through systematic transformation operations.
Solution Approach 2:
The patent transforms the signal representation by applying FFT to convert time-domain segments to frequency-domain representations, then applies bandwidth restriction by zeroing out-of-band components, and finally applies IFFT to convert back to time domain. These parameter changes enable signals to be generated with accurate frequency domain specification while maintaining efficient bandwidth utilization.
3Measurement precision
If signal segmentation and transformation operations are applied, then frequency domain specification accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent divides the complex task of frequency domain specification into manageable segments processed sequentially. Each segment undergoes FFT transformation, bandwidth restriction, and IFFT transformation independently. This segmentation reduces processing complexity compared to attempting to transform the entire long sequence at once, while maintaining frequency domain specification accuracy.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A transmitting device may identify a first signal in a time domain, the first signal including multiple sequences spanning a bandwidth for multiple symbol periods. The transmitting device may segment the first signal into signal segments, where each signal segment corresponds to a respective symbol period of the multiple symbol periods. The transmitting device may apply a first transform operation to each signal segment of the signal segments and apply a bandwidth restriction in the frequency domain to the transformed signal segments. Then, the transmitting device may apply a second transform operation to each transformed signal segment to return the bandwidth-restricted segments to the time domain. The transmitting device may generate a second signal in the time domain based on the bandwidth-restricted segments. The transmitting device may then transmit the second signal to a receiving device.