Wireless Base Station Muting for Intercell Interference
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Solution Overview
Problem
In heterogeneous wireless communication networks, intercell interference between macrocells and picocells degrades communication quality due to overlapping downlink control and shared channels, particularly when macrocells override shared channels with null symbols, leading to degraded reception characteristics and inability to decode code blocks.
Innovation Solution
The system controls transmission timing to overlap control and shared channels, with the macro base station determining a muting amount based on the number of code blocks for each mobile station, selectively muting only when necessary to avoid whole code block override and maintain reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the macro base station overrides the downlink shared channel with a null symbol to reduce intercell interference to the pico base station's control channel, then intercell interference is reduced, but the reception characteristic of the macro base station's own downlink shared channel becomes degraded
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different code blocks based on their specific characteristics. Instead of uniformly overriding all code blocks with null symbols, the system selectively overrides only those code blocks that can be recovered through interference cancellation, while preserving code blocks that are critical for maintaining reception quality. This localized differentiation resolves the contradiction by applying interference reduction only where it does not compromise overall system reliability.
Solution Approach 2:
The patent implements dynamics by making the override decision adaptive rather than static. The system dynamically determines whether to override a code block based on real-time conditions including the number of code blocks, channel state information, and interference levels. This dynamic approach allows the system to adjust the degree of interference suppression based on current operational conditions, preventing permanent degradation of reception characteristics while still reducing intercell interference when appropriate.
2Object-affected harmful factors
If the macro base station overrides a whole code block with a null symbol, then intercell interference to the control channel is reduced, but it becomes impossible to decode the code block and restore original information bits
Solution Approach 1:
The patent applies partial action by selectively overriding only certain code blocks rather than entire messages or all code blocks. The system identifies specific code blocks that are suitable for override based on the number of code blocks and their individual characteristics, overriding only those that can be recovered through interference cancellation techniques. This partial approach allows interference reduction while preserving the integrity of critical information bits in other code blocks.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of interference cancellation and recovery processes. When a code block is overridden with a null symbol, the system uses interference cancellation techniques to recover the original information bits from the pico base station's control channel signals. This intermediary recovery process acts as a bridge, allowing the system to suppress interference while potentially restoring the original information, thus preventing permanent information loss.
3Productivity
If downlink control channels are distributed over the entire system bandwidth, then frequency resource utilization is improved, but it becomes difficult to apply FFR and intercell interference occurs between control channels
Solution Approach 1:
The patent applies parameter changes by modifying the timing parameters of downlink shared channel transmissions. Specifically, the system adjusts the timing of shared channel transmissions relative to control channels, creating temporal separation that prevents interference. This parameter adjustment allows the system to maintain full bandwidth utilization for control channels while avoiding interference through careful timing coordination, effectively resolving the contradiction between resource utilization and interference prevention.
Data Source
AI summary
It is an object of the invention to provide a wireless communication system capable of decoding a downlink shared channel of an interfering cell while achieving the reduction of intercell interference to a downlink control channel of an interfered cell. In a wireless communication system that controls transmission timing of each base station so that a control channel transmitted by a first base station and a shared channel transmitted by a second base station temporally overlap, the second base station includes a muting control unit and a muting processing unit that transmit a null symbol in an overlapping time interval of the shared channel with a time interval of the control channel on the basis of the number of code blocks in a data signal component for each mobile station corresponding to the overlapping time interval of the shared channel with the time interval of the control channel.