Femto Subnet Color Code Configuration for Seamless Handoff
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Solution Overview
Problem
In wireless networks with femto cells and macro cells, slow-moving mobiles experience service interruptions due to the secondary color code mechanism, which causes delayed handoffs and leaves devices unserved for extended periods when moving between overlapping coverage areas.
Innovation Solution
The radio access network configures specific color codes for femto and macro subnets, broadcasting these codes to trigger seamless handoffs between femto and macro subnets by assigning primary and secondary color codes to bordering femto cells and macro cells, ensuring timely registration and idle handoff without unnecessary service interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the secondary color code mechanism is applied at bordering macro cells to provide spatial hysteresis and suppress ping-pong effects, then handoff stability is improved, but service continuity deteriorates because slow-moving mobiles experience extended periods without service during handoff transitions
Solution Approach 1:
The patent segments the color code mechanism by applying secondary color codes only to bordering macro cells rather than all macro cells. This selective segmentation allows spatial hysteresis to be provided at critical border areas while avoiding unnecessary delays in non-border areas, thus reducing overall service interruption time while maintaining handoff stability where needed
Solution Approach 2:
The patent implements local quality by differentiating the color code behavior based on cell location. Bordering macro cells broadcast secondary color codes to provide spatial hysteresis and prevent ping-pong effects, while non-bordering macro cells do not. This localized application of the secondary color code mechanism optimizes the balance between handoff stability and service continuity for different parts of the network
2Measurement precision
If bordering macro cells broadcast both primary and secondary color codes to indicate border area status, then mobile station handoff decision accuracy is improved, but mobile station response time deteriorates due to the additional processing required to evaluate secondary color codes
Solution Approach 1:
The patent applies partial action by having bordering macro cells broadcast secondary color codes only when necessary (i.e., when actually bordering a femto cell), rather than universally. This selective broadcast provides accurate handoff decision information for border areas while minimizing unnecessary processing time for mobile stations in non-border areas
Data Source
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AI summary
In a method for configuring a wireless network, a radio access network establishes a first color code for a femto subnet and a second color code for a macro subnet. The femto subnet includes a plurality of femto cells, and the macro subnet includes at least one macro cell. The macro subnet borders the femto subnet. The radio access network identifies the plurality of femto cells bordering the macro subnet, and assigns the established first and second color codes to the identified border femto cells, while assigning only the first color code to non-bordering femto cells.