Asymmetric Filter Function for Adjacent Subband Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In radio communication systems, existing methods struggle to efficiently manage interference between signals transmitted on adjacent subbands, particularly in scenarios where variable data rates and bursty traffic patterns occur, leading to suboptimal utilization of bandwidth and increased peak-to-average power ratio (PAPR).
Innovation Solution
A method where user stations adjust their filtering parameters based on the occupancy of adjacent subbands, using information received from the base station to determine the filter function, thereby adapting the frequency allocation and reducing interference by varying the filter bandwidth and roll-off factor α, ensuring efficient signal transmission without overlapping into adjacent subbands when occupied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the entire available frequency band is split into multiple subbands for multicarrier transmission, then data transmission efficiency and bandwidth utilization are improved, but interference between adjacent subbands increases and peak-to-average power ratio (PAPR) increases
Solution Approach 1:
The patent applies local quality by making the filter function asymmetric at the edges of allocated subbands. Specifically, when a subband is adjacent to an occupied subband, the filter function is designed with different characteristics on each side: a steeper roll-off toward the occupied subband and a gentler roll-off toward the unoccupied subband. This localized adaptation of filter characteristics reduces interference into occupied subbands while maintaining efficient bandwidth utilization.
Solution Approach 2:
The patent implements dynamics by making the filter function adaptive based on the occupancy status of adjacent subbands. The base station determines the filter characteristics dynamically according to which subbands are currently occupied by which user stations. This dynamic adaptation allows the system to optimize the trade-off between bandwidth utilization and interference reduction in real-time based on traffic conditions.
2Object-generated harmful factors
If filtering with a steep roll-off is applied to reduce adjacent channel interference, then interference between subbands is reduced, but bandwidth utilization decreases and data transmission efficiency is reduced
Solution Approach 1:
The patent applies local quality by making the filter function asymmetric at the edges of allocated subbands. Specifically, when a subband is adjacent to an occupied subband, the filter function is designed with different characteristics on each side: a steeper roll-off toward the occupied subband and a gentler roll-off toward the unoccupied subband. This localized adaptation of filter characteristics reduces interference into occupied subbands while maintaining efficient bandwidth utilization.
3Productivity
If the filter bandwidth is increased to improve data transmission efficiency, then productivity is improved, but interference with adjacent subbands increases
Solution Approach 1:
The patent applies local quality by making the filter function asymmetric at the edges of allocated subbands. Specifically, when a subband is adjacent to an occupied subband, the filter function is designed with different characteristics on each side: a steeper roll-off toward the occupied subband and a gentler roll-off toward the unoccupied subband. This localized adaptation of filter characteristics reduces interference into occupied subbands while maintaining efficient bandwidth utilization.
4Object-generated harmful factors
If asymmetric filter functions are applied at subband edges adjacent to occupied subbands, then adjacent channel interference is reduced, but filter complexity increases
Solution Approach 1:
The patent applies preliminary action by having the base station pre-determine and signal the filter function characteristics to user stations before transmission. The base station calculates the appropriate asymmetric filter parameters based on the subband allocation and occupancy information, then provides this information to the user stations via downlink signaling. This allows user stations to apply the correct filter characteristics without performing complex real-time analysis, reducing their computational complexity.
Data Source
AI summary
In a method for communication by radio afrequency band that is subdivided into a plurality of subbands is used. Subbands are occupied by radio stations for sending signals. Before sending a signal, a radio station carries out a filtering operation by using a filter function and sends the signal on at least one subband. A parameter of the filter function depends on the occupation of at least one subband adjacent to the at least one subband.