Femtocell Interference Reduction via Channel Gain Feedback
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Solution Overview
Problem
Femtocell base stations cause interference both to macro base stations and each other due to random deployment and lack of unified backhaul, leading to difficulties in information sharing and coordination, especially when competing for the same frequency band.
Innovation Solution
A method and Femtocell base station design that use spectrum sensing to determine the average channel gain and identify P channels causing the greatest interference and N channels suffering the most interference, allowing signals to be transmitted or received in channels other than these, thereby reducing inter-Femtocell interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Femtocell base stations are deployed independently and randomly to provide high-speed indoor wireless access, then deployment flexibility and ease of installation are improved, but inter-Femtocell interference and coordination difficulty increase
Solution Approach 1:
The patent implements a feedback mechanism where each Femtocell base station detects the channel gain to a reference Femtocell base station and reports this information back to the reference station. The reference station uses this feedback to determine appropriate transmit power levels for each channel, thereby reducing inter-Femtocell interference while maintaining deployment flexibility
Solution Approach 2:
The patent dynamically adjusts the transmit power parameter of Femtocell base stations based on detected channel conditions. By changing the power parameter adaptively according to channel gain measurements, the system reduces interference to both macro base stations and other Femtocell base stations while maintaining ease of deployment
2Device complexity
If Femtocell base stations contend to access the same frequency band without unified backhaul, then network simplicity and cost-effectiveness are improved, but information sharing and coordination capability deteriorate
Solution Approach 1:
The patent introduces a reference Femtocell base station as an intermediary that collects channel gain information from other Femtocell base stations. This intermediary role enables information sharing among distributed Femtocell stations without requiring a complex unified backhaul network, as each station only needs to communicate with the reference station
Solution Approach 2:
Each Femtocell base station autonomously detects and measures the channel gain to the reference station, performing self-measurement and self-reporting. This self-service approach enables information gathering without requiring complex centralized control or sophisticated coordination mechanisms, maintaining network simplicity
3Object-affected harmful factors
If spectrum sensing is used to identify P channels causing greatest interference and N channels suffering greatest interference, then inter-Femtocell interference reduction is improved, but measurement and detection complexity increases
Solution Approach 1:
Each Femtocell base station autonomously performs channel gain detection to a reference station and independently determines which channels cause interference and which channels suffer interference. This self-service detection approach simplifies the overall system by eliminating the need for complex centralized measurement coordination, reducing detection complexity while effectively identifying P and N channels
Data Source
Figure 1~2
AI summary
The present invention discloses a method for reducing inter-Femtocell interference, including: obtaining an average channel gain of all available channels; determining whether the average channel gain is greater than a preset threshold; if the average channel gain is greater than the preset threshold, determining, by using spectrum sensing, a P channel and an N channel, where the P channel is one or more available channels causing greatest interference and the N channel is one or more available channels suffering greatest interference; and transmitting or receiving a signal in an available channel other than the P channel and the N channel. An embodiment of the present invention further provides a corresponding Femtocell base station. With the technical solutions of the present invention, when the average channel gain of all available channels is greater than a preset threshold, the P channel and the N channel are determined and excluded, so that signals are transmitted or received only in other available channels. In this way, not only interference caused to other Femtocell base stations can be reduced, but also interference suffered from other Femtocell base stations can be reduced.