Base Station Interference Removal Using Inverted Frames
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Solution Overview
Problem
In LTE network environments where macro and small base stations using FDD coexist, signal interference occurs due to shared frequency bands for uplink and downlink transmissions, degrading communication quality.
Innovation Solution
A base station device with a signal receiving unit to receive downlink signals from adjacent base stations over uplink frequency bands, a measuring unit to assess the channel environment, and an interference removing unit to subtract calculated signal components from received signals, using inverted and silence inverted frames to separate uplink and downlink frequency band allocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If macro base stations and small base stations use a common frequency band for uplink/downlink transmission, then network coverage and capacity are improved, but signal interference between base stations increases
Solution Approach 1:
The frequency band is segmented into different portions for uplink and downlink transmissions. Specifically, the base station divides the common frequency band such that different frequency resources are allocated for uplink and downlink, allowing simultaneous operations while reducing interference between co-channel base stations.
Solution Approach 2:
The patent applies inverted frame structure where the uplink and downlink frequency band allocations are inverted relative to conventional FDD. During inverted frames, the base station allocates frequency bands in reverse manner, and during silence inverted frames, uplink transmission is silenced to allow downlink reception without interference.
2Productivity
If frequency division duplex (FDD) is used with common frequency bands, then uplink and downlink transmissions can occur simultaneously, but interference between uplink signals and downlink signals occurs
Solution Approach 1:
The frequency band is divided into multiple segments with different allocations for uplink and downlink. The base station configures specific frequency resources for uplink transmission and different frequency resources for downlink transmission within the common band, enabling simultaneous operations while minimizing interference through frequency separation.
Solution Approach 2:
The patent implements periodic switching between normal frames and inverted frames. During normal frames, conventional FDD operation occurs; during inverted frames, frequency allocations are inverted; and during silence inverted frames, uplink transmission is periodically silenced to allow clean downlink reception. This periodic action pattern reduces cumulative interference.
Data Source
AI summary
A base station device includes: a signal receiving unit to receive a downlink signal, which is transmitted from an adjacent base station over a downlink frequency band of a frame for the adjacent base station, over an uplink frequency band of a silent inverted frame during a first time interval, during which the base station device uses the silence inverted frame; a measuring unit to measure a channel environment with the adjacent base station based on the downlink signal from the adjacent base station; and an interference removing unit configured to remove the signal interference induced from the adjacent base station by removing the downlink signal received from the adjacent base station over a uplink frequency band of the base station device during a second time interval based on the channel environment with the adjacent base station.