Cell Selection Control Using Traffic Flow Direction in Heterogeneous Networks
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Solution Overview
Problem
Conventional cell selection schemes in heterogeneous cellular networks often prioritize downlink signal strength over uplink, leading to suboptimal data rates and increased interference, particularly in transition zones between macro and pico base station cells.
Innovation Solution
The method involves determining the primary direction of traffic flow for user equipment (UE) and adjusting the border of the pico base station cell to favor selection of either the macro or pico base station based on this direction, using a user equipment cell selection offset value to optimize cell selection and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cell selection schemes prioritize downlink signal strength, then downlink connection quality is improved, but uplink data rate deteriorates and interference increases
Solution Approach 1:
The patent changes the cell selection parameter from downlink signal strength alone to a composite metric that includes both downlink and uplink signal qualities. The base station determines uplink signal quality by measuring the received signal from the UE and compares it with downlink signal quality measurements, then uses this combined information to make cell selection decisions, thereby resolving the contradiction between downlink connection quality and uplink data rate.
2Reliability
If conventional cell selection schemes prioritize downlink signal strength, then downlink connection quality is improved, but network interference increases
Solution Approach 1:
The patent modifies the cell selection criterion by incorporating uplink signal quality measurements into the decision-making process. The base station evaluates both downlink and uplink signal qualities and selects cells based on this comprehensive assessment, which prevents UEs with poor uplink conditions from being assigned to cells that would generate excessive interference, thus reducing overall network interference while maintaining downlink connection quality.
3Reliability
If pico base stations are deployed in heterogeneous networks, then service quality in hotspots is improved, but cell selection complexity increases
Solution Approach 1:
The patent introduces an intermediary mechanism where the base station actively measures and evaluates uplink signal quality and uses this information to guide UE cell selection. This intermediary approach simplifies the UE's cell selection process by providing clear selection criteria based on combined downlink and uplink quality metrics, reducing the complexity that would otherwise arise from the heterogeneous network architecture with multiple base station types.
Data Source
AI summary
Systems and methods are disclosed for controlling cell selection between a high power base station and a neighboring low power base station in a cellular network. In one embodiment, a primary direction of traffic flow for a user equipment located within a transition zone between a high power base station cell of the high power base station and a low power base station cell of the low power base station is determined to be either an uplink direction or a downlink direction. Cell selection for the user equipment is then controlled based on the primary direction of traffic flow for the user equipment such that selection of the high power base station cell is favored if the primary direction of traffic flow is the downlink direction and selection of the low power base station cell is favored if the primary direction of traffic flow is the uplink direction.