Relay Scheduling for Interference Mitigation in Wireless Networks
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Solution Overview
Problem
In wireless communications systems with relay stations, inter-cell interference in boundary areas leads to poor signal-to-interference noise ratio (SINR) due to a common slot allocation method across the network.
Innovation Solution
Implementing multiple slot type allocation sequences and a deployment pattern where different base station sectors and their associated relay stations use non-overlapping slot sequences to mitigate interference, allowing access terminals to determine the appropriate sequence for communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a common slot allocation method is used throughout the network, then system simplicity and ease of operation are improved, but inter-cell interference in boundary areas increases leading to poor SINR
Solution Approach 1:
The patent segments the network into different slot type allocation sequence groups, where each group uses a distinct sequence pattern. This segmentation allows neighboring cells to have non-overlapping relay-to-access slots, thereby reducing inter-cell interference while maintaining manageable complexity through structured grouping.
Solution Approach 2:
The patent applies different slot type allocation sequences to different geographic regions or cell groups. Each local area uses a sequence optimized for its specific interference environment, allowing boundary regions to experience reduced interference from neighboring cells while interior regions maintain efficient resource utilization.
2Object-affected harmful factors
If multiple slot type allocation sequences are implemented with different sequences in neighboring cells, then inter-cell interference is reduced improving SINR, but system complexity and device complexity increase
Solution Approach 1:
The patent implements periodic patterns in slot type allocation sequences, where each cell group follows a repeating sequence of slot types. This periodic structure reduces complexity by providing predictable, cyclic patterns that devices can easily track and synchronize to, rather than requiring complex aperiodic scheduling.
Solution Approach 2:
The patent creates equipotential conditions by ensuring that all cells within a sequence group follow the same slot allocation pattern. This uniformity within groups simplifies device operation and synchronization, as terminals can expect consistent slot structures from all base stations in their serving group.
3Object-affected harmful factors
If multiple slot type allocation sequences are implemented, then interference mitigation capability is improved, but loss of time for determining appropriate sequence increases
Solution Approach 1:
The patent performs preliminary configuration by pre-assigning cells to specific slot type allocation sequence groups during network deployment. This preliminary action eliminates the need for complex real-time sequence selection, as devices can immediately use the pre-determined sequence for their serving cell, reducing determination time while maintaining interference mitigation benefits.
Data Source
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AI summary
Methods and apparatus relating to interference mitigation in a wireless communications system including multi-sector base stations and relay stations are described. Different types of transmission slots are used, e.g., base station-relay station slots, relay station-access terminal slots, and base station-access terminal slots. Relay station to access terminal slots of a first schedule are non-overlapping with relay station to access terminal slots of a second schedule. A deployment pattern associates each particular base station sector and its associated relay station with one particular schedule. At least some different sectors of the same base station intentionally use different schedules. An access terminal determines and uses the schedule corresponding to the base station sector or relay station from which it intends to receive downlink signals. By utilizing multiple slot type allocation schedules and a particular schedule deployment pattern in the system, interference experienced by access terminals in boundary regions can be mitigated.