Coordinated Scheduling for Inter-Cell Interference in Wireless Systems
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Solution Overview
Problem
Conventional wireless communication systems face challenges in reducing interference between cells, particularly for cell-edge user devices, due to the lack of coordination in the use of pre-coding matrices, which affects data throughput and quality of service.
Innovation Solution
The system employs coordinated scheduling by receiving and evaluating utility values for different pre-coding matrices across access points to determine the optimal usage, restricting interference-causing matrices and allowing beneficial ones, thereby improving signal-to-interference and noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If access points independently select pre-coding matrices without coordination, then each access point can optimize its own data throughput, but inter-cell interference increases and overall spectral efficiency deteriorates
Solution Approach 1:
The patent merges the scheduling decisions of multiple access points by introducing a coordination mechanism where access points exchange information about their intended pre-coding matrix selections. The network controller aggregates utility values from multiple access points and makes centralized scheduling decisions, combining individual optimizations into a coordinated system-wide optimization that reduces inter-cell interference while maintaining overall throughput.
Solution Approach 2:
The patent implements feedback loops where access points report their channel state information and intended pre-coding matrix selections to a network controller. The controller evaluates the impact of each access point's selection on other cells and provides feedback recommendations or restrictions. This feedback mechanism enables iterative optimization where access points adjust their pre-coding matrix selections based on network-wide interference conditions, resolving the contradiction between individual throughput optimization and overall interference reduction.
2Object-affected harmful factors
If pre-coding matrices are restricted to reduce interference, then inter-cell interference decreases and spectral efficiency improves, but the scheduling flexibility and adaptability of access points are reduced
Solution Approach 1:
The patent applies dynamic scheduling where the restriction of pre-coding matrices is not static but adapts to changing channel conditions and network load. The network controller dynamically evaluates utility values based on current channel states and traffic demands, adjusting which pre-coding matrices are restricted or recommended for each access point in each scheduling interval. This dynamic approach maintains scheduling flexibility while achieving interference reduction, as restrictions are applied adaptively rather than uniformly.
Solution Approach 2:
The patent implements local quality by allowing different access points to have different sets of restricted or recommended pre-coding matrices based on their specific geographic location, channel conditions, and interference environment. Rather than applying uniform restrictions across the network, each access point receives customized scheduling decisions tailored to its local conditions. This preserves adaptability at the local level while achieving overall interference reduction through coordinated scheduling.
3Productivity
If coordinated scheduling information is exchanged between access points, then interference coordination improves and network capacity increases, but system complexity and information processing requirements increase
Solution Approach 1:
The patent introduces a network controller as an intermediary that centralizes the coordination function. Instead of requiring direct communication and complex peer-to-peer coordination between multiple access points, the network controller acts as a mediator that collects scheduling information from all access points, evaluates utility values, and distributes coordinated scheduling decisions. This intermediary approach simplifies the system architecture by centralizing the complex information processing and decision-making functions, reducing the coordination overhead compared to distributed approaches.
Data Source
AI summary
A system and method of coordinating scheduling in a wireless communication system are described herein. In one aspect, cells receive information regarding one or more precoding matrices from user equipments. The information may include a request from an user equipment that the cell not use a particular precoding matrix for communications. The cell may determine whether restricting usage of the precoding matrix for communication improves overall communication in the wireless communication system by performing pair-wise comparisons of utility based on usage and restriction of the precoding matrix. The cell may further resolve conflicts that arise between several cells based on the granting of restriction of the precoding matrix.