Wireless Handover System Information Acquisition via Interference Management
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Solution Overview
Problem
In wireless communication systems, user equipment faces challenges in obtaining system information during handover procedures, especially in interference situations where signal strength from the target cell is weaker than the serving cell, leading to difficulties in synchronization and system information acquisition.
Innovation Solution
The solution involves using a subframe offset and synchronization signals from the serving cell to assist the user equipment in synchronizing with the target cell, allowing it to obtain system information even in interference conditions by reusing information from the handover process and assuming synchronized time boundaries between cells, thereby minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user equipment attempts to obtain system information from the target cell during handover, then system information acquisition is enabled, but interference from the serving cell prevents successful reception
Solution Approach 1:
The network pre-configures the user equipment with ABS (Almost Blank Subframe) patterns and time boundary offset information before handover. This allows the UE to identify subframes where the serving cell is silent, enabling it to receive system information from the target cell without interference during these pre-identified quiet periods.
Solution Approach 2:
The patent converts the interference problem by utilizing the ABS mechanism where the serving cell intentionally creates silent subframes. These harmful interference periods are transformed into beneficial reception opportunities by scheduling target cell system information transmission during these silent periods, turning the serving cell's interference pattern into a resource for successful handover.
2Reliability
If user equipment uses synchronization signals from the serving cell to synchronize with the target cell, then synchronization is achieved, but system information may be missed due to timing misalignment
Solution Approach 1:
The network acts as an intermediary by providing offset information that bridges the timing relationship between the serving cell and target cell. This offset information serves as a mediator that allows the user equipment to correctly time-align its reception of system information from the target cell based on the serving cell's synchronization signals, eliminating timing misalignment issues.
3Loss of information
If the target cell transmits system information continuously, then information availability is maximized, but interference from the serving cell increases
Solution Approach 1:
The patent implements periodic transmission of system information during ABS silent subframes rather than continuous transmission. The target cell transmits system information in periodic intervals corresponding to the ABS pattern, which reduces overall interference while ensuring information is available at regular, predictable intervals for the user equipment to acquire.
Data Source
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AI summary
The present invention relates to a method for a terminal to perform a handover in a wireless communication system, including the steps of: receiving a handover instruction from a serving cell; and performing a random access procedure for a target cell according to the handover instruction, wherein, when interference adjustment is performed on the serving cell and the target cell, system information for the target cell is obtained from the serving cell.