OFDM Channel Flatness Compensation via Frequency Domain Lookup
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Solution Overview
Problem
Existing channel flatness compensation methods for 5G OFDM technologies face challenges in achieving accurate compensation, flexibility, and low computational overhead, especially in wide bandwidth and multi-band applications, due to the need for reconfiguring FIR filters and high-order convolution operations.
Innovation Solution
A method and apparatus that utilize a pre-configured frequency domain compensation table to directly determine a target compensation vector for sub-carriers, eliminating the need for reconfiguring filters and reducing computational overhead by performing operations in the frequency domain, allowing for immediate and accurate channel flatness compensation without disrupting data continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FIR filter is used to compensate channel unflatness in time domain, then channel flatness compensation is achieved, but reconfiguration is required when bandwidth or center frequency changes, affecting data continuity
Solution Approach 1:
The patent pre-calculates and stores compensation vectors for multiple bandwidth configurations and center frequencies in a lookup table during system initialization. When operation begins, the appropriate compensation vector is directly retrieved from the table based on current configuration parameters, eliminating the need for real-time filter reconfiguration and maintaining data continuity without interruption
Solution Approach 2:
The patent transforms the compensation approach from time-domain FIR filtering to frequency-domain vector multiplication. By changing the operational parameters from filter coefficients to pre-computed compensation vectors stored in lookup tables, the system achieves instantaneous adaptation to bandwidth and frequency changes without reconfiguration delay
2Measurement precision
If high-order FIR filter is used to accurately compensate wide bandwidth signals, then sub-carrier level compensation accuracy is achieved, but computation amount and hardware overhead become huge
Solution Approach 1:
The patent replaces complex high-order FIR filter computations with pre-computed compensation vectors stored in lookup tables. Instead of performing real-time convolution operations with numerous filter coefficients, the system copies the appropriate compensation vector from storage and applies it through simple element-wise multiplication, dramatically reducing hardware complexity while maintaining sub-carrier level accuracy
Solution Approach 2:
The patent computes compensation vectors only for the specific bandwidth configurations and frequency bands that are actually needed for operation, rather than implementing a general-purpose high-order filter that would handle all possible cases. This targeted approach achieves necessary accuracy for each specific scenario with minimal computational resources
Data Source
AI summary
Provided are a channel flatness compensation method, a channel flatness compensation apparatus, a storage medium, a baseband chip, and a device, wherein the method is applied to a transmitting link modulated by orthogonal frequency division multiplexing and includes: receiving an input vector of a current sub-carrier subjected to sub-carrier mapping processing, and determining current values of preset configuration parameters corresponding to the current sub-carrier; querying a preset frequency domain compensation table according to the current values of the preset configuration parameters, and determining a target compensation vector according to a query result; and determining an output vector of the current sub-carrier according to the input vector and the target compensation vector, wherein the output vector is used in an inverse fast Fourier transform operation.