Femtocell Frame Switching to Avoid Macro Uplink Interference
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Solution Overview
Problem
In heterogeneous cellular networks, uplink interference between macrocells and femtocells degrades communication performance, as existing methods either limit frequency resource usage or restrict access to all frequency resources, necessitating a solution to enhance performance while avoiding interference.
Innovation Solution
The method involves switching the ordinal positions of femtocell uplink and downlink frames based on the degree of macro uplink interference, using signal-to-noise ratio calculations to determine optimal frame positioning and relaying macrodata through a selected femtocell base station, allowing concurrent processing of femtocell downlink and macrodata transmission using superposition coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency resources of macrocell and femtocell are allocated orthogonally, then interference between macrocell and femtocell is reduced, but performance of each cell is limited due to restrictions on frequency resource usage
Solution Approach 1:
The patent dynamically switches the ordinal positions of femtocell uplink and downlink frames based on the degree of macro uplink interference. When interference is strong, the femtocell uplink frame position is switched to avoid interference with macrocell uplink transmission. This dynamic adjustment allows the system to adapt to changing interference conditions while maintaining full frequency resource usage, resolving the contradiction between reducing interference and maintaining performance.
2Productivity
If all frequency resources are allocated to macrocell or femtocell exclusively, then each cell can use all frequency resources, but one cell is not allowed to use all frequency resources
Solution Approach 1:
The patent implements periodic switching of frame ordinal positions based on interference conditions. The femtocell base station determines whether to switch positions by evaluating the degree of macro uplink interference, and this switching decision is applied periodically to avoid interference while allowing both macrocell and femtocell to utilize all frequency resources at different times, thus resolving the resource allocation contradiction.
3Productivity
If femtocell uplink frame is transmitted during macrocell uplink frame transmission, then full frequency resources can be used, but uplink interference in macrocell is caused
Solution Approach 1:
The femtocell base station performs preliminary evaluation of macro uplink interference conditions before transmitting the femtocell uplink frame. By determining the degree of interference in advance and switching the ordinal position proactively when interference is detected, the system prevents interference from occurring while maintaining the ability to use full frequency resources when conditions permit.
Data Source
AI summary
Provided are a method and a device for avoiding interference of an uplink in a macro cell within a heterogeneous cellular network system. A femtocell base station calculates a degree of the interference of the uplink in the macro cell, and determines whether the interference is strong. If the interference of the uplink in the macro cell is strong, the femtocell base station changes the order of a femtocell uplink frame and a femtocell downlink frame.