Ranging Signal Subband Allocation for FFR Interference Reduction
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Solution Overview
Problem
In wireless communication systems supporting Fractional Frequency Reuse (FFR), the existing methods for transmitting ranging signals do not account for FFR, leading to interference with neighboring cells due to the selection of subbands across the entire frequency band without considering power limitations in Frequency Partition areas.
Innovation Solution
A method and apparatus for a mobile station and base station to determine a subband index for ranging signal transmission based on the cell identifier and the number of subbands allocated to specific Frequency Partition areas, restricting subband allocation to the reuse 1 and power-boosted reuse 3 areas to minimize interference, using modified modulo operations and frequency partition location parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If subband selection is performed across the entire frequency band without considering FFR, then the mobile station can access the ranging signal in any subband, but interference with neighboring cells occurs due to power limitations in Frequency Partition areas
Solution Approach 1:
The patent applies local quality by determining subband index based on the mobile station's location within Frequency Partition areas. Different locations receive different subband allocations, ensuring that mobile stations in cell boundary areas are assigned subbands that avoid interfering with neighboring cells while maintaining flexibility in subband selection
Solution Approach 2:
The patent changes the parameter used for subband index determination from a simple modulo operation on subband number to a location-aware calculation that considers Frequency Partition area information. This parameter change enables the system to adapt subband allocation to the specific FFR configuration and mobile station location, reducing interference while preserving access flexibility
2Object-affected harmful factors
If FFR is applied to reduce interference in cell boundary areas, then interference with neighboring cells is reduced, but the existing ranging signal transmission method does not account for FFR, causing interference to occur
Solution Approach 1:
The patent applies preliminary action by determining the subband index before ranging signal transmission based on the mobile station's location and FFR configuration. This pre-determination ensures that the ranging signal is transmitted on a subband that avoids interfering with neighboring cells, maintaining both interference reduction and transmission reliability
Solution Approach 2:
The patent uses feedback from the mobile station's location information and FFR configuration to dynamically determine the appropriate subband index. This feedback mechanism ensures that ranging signal transmission adapts to the FFR setup, maintaining reliability while reducing interference in cell boundary areas
Data Source
AI summary
A method of a mobile station for transmitting a ranging signal in a wireless communication system which supports Fractional Frequency Reuse (FFR) and an apparatus for performing the method are provided. The method includes receiving information of ranging resource allocation, from a base station, based on the information of the ranging resource allocation, determining a cell identifier and a Frequency Partition (FP) location for uplink control channels, determining a subband index for the ranging resource allocation based on the cell identifier and a number of subbands allocated to the FP location for the uplink control channels, and transmitting a ranging signal based on the subband index for the ranging resource allocation. Thus, interference to a neighboring cell may be reduced in the ranging channel transmission.