Paging Slot Timing Adjustment for Interference Mitigation
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Solution Overview
Problem
In multi-tier wireless communication systems, femtocells and macrocells face interference issues due to overlapping paging signals, leading to reduced effectiveness in delivering paging messages to mobile stations, especially when femtocells operate in active intervals, overwhelming macrocell signals.
Innovation Solution
Implementing a method where base stations adjust paging slots to overlap with unavailable intervals of other base stations, using low duty cycle modes to minimize interference, and mobile stations recalculating listening slots to align with available intervals, thereby reducing interference and ensuring reliable paging message delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If femtocells operate in active intervals to provide wireless data traffic, then service coverage and data transmission capability are improved, but interference with macrocell paging signals increases
Solution Approach 1:
The femtocell base station dynamically adjusts its active intervals based on the timing of macrocell paging slots. The system determines overlapping periods between femtocell active intervals and macrocell paging slots, then modifies femtocell transmission timing to avoid these overlapping periods, creating a dynamic adaptation mechanism that resolves the interference contradiction
Solution Approach 2:
The system changes the timing parameters of femtocell active intervals by determining their overlap with macrocell paging slots and adjusting the occurrence timing. This parameter modification ensures that femtocell transmissions occur in unavailable intervals of macrocells, reducing interference while maintaining data transmission capability
2Reliability
If paging slots are transmitted frequently to ensure reliable delivery, then paging reliability is improved, but interference with other base station transmissions increases
Solution Approach 1:
The base station performs preliminary determination of overlapping periods between paging slots and other base station active intervals before transmitting paging messages. By identifying these overlapping periods in advance, the system can schedule paging transmissions in unavailable intervals, ensuring reliable delivery without causing interference to other base stations
3Duration of action of moving object
If femtocell active intervals are extended to cover more time periods, then service availability is improved, but overlap with macrocell paging slots increases
Solution Approach 1:
The system segments the time domain into available intervals and unavailable intervals for femtocell transmissions. By dividing the time resource and assigning different transmission states to different intervals, the system allows extended service availability in available intervals while avoiding interference during unavailable intervals that correspond to macrocell paging slots
Data Source
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AI summary
A first base station and mobile station are capable of mitigating interference resulting from communications from a second base station. The base station can determine if at least a portion of a paging slot overlaps with an available interval (AI) of the second base station in which the second base station transmits. The first base station adjusts an occurrence of the paging slot such that the paging slot overlaps and/or occurs within an unavailable interval (UAI) of the second base station wherein the base station does not transmit or transmits with limited resources. The mobile station also can determine if at least a portion of a listening slot overlaps with the AI and, using the same procedure that the first base station uses to recalculate the paging slot, recalculates the listening slot such that the listening slot overlaps and/or occurs within the UAI of the LDC mode.