HSM Pilot Threshold Offset for Handover Control
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Solution Overview
Problem
High-speed User Equipments (UEs) often fail to complete handover operations from macrocells to small cells or between neighboring small cells, leading to incomplete handover processes that waste network resources due to their rapid traversal through small cell coverage areas.
Innovation Solution
Implementing a High Speed Mobility (HSM) pilot strength threshold offset parameter to adjust handover thresholds, allowing UEs to remain connected to macrocells when in HSM mode by modifying pilot strength thresholds for handover decisions, thereby reducing unnecessary handover attempts and resource wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE performs handover operations from macrocell to small cell based on existing mechanisms, then traffic offloading capacity is improved, but incomplete handover processes occur when UE moves at high speed causing network resource waste
Solution Approach 1:
The network determines whether a UE is in HSM mode before initiating handover operations. By preliminarily identifying high-speed mobility conditions and configuring appropriate handover parameters (such as adjusted pilot strength thresholds and timing advances), the system prevents incomplete handovers before they occur, thereby avoiding network resource waste while maintaining traffic offloading capability
Solution Approach 2:
The patent modifies handover parameters dynamically based on UE mobility state. When HSM mode is detected, parameters such as pilot strength thresholds, handover margins, and timing advance values are adjusted to accommodate high-speed movement. This parameter adaptation enables successful handovers for fast-moving UEs while preventing unnecessary handovers for slow-moving UEs, thus resolving the contradiction between traffic offloading and resource efficiency
2Productivity
If handover threshold is lowered to enable more handovers to small cells, then traffic offloading is improved, but incomplete handovers increase for high-speed UEs
Solution Approach 1:
The handover threshold is made dynamic rather than static. The system adjusts the pilot strength threshold and handover margin based on the UE's mobility state. For HSM-mode UEs, higher thresholds and larger margins are applied to ensure handover completion, while for normal-mode UEs, lower thresholds enable aggressive traffic offloading. This dynamic adaptation resolves the contradiction between maximizing traffic capacity and ensuring handover reliability
3Adaptability or versatility
If handover operations are allowed for all UEs regardless of speed, then network coverage is improved, but resource efficiency deteriorates due to processing incomplete handovers
Solution Approach 1:
The patent segments the UE population into different mobility categories (HSM mode and normal mode) based on their movement characteristics. This segmentation allows the network to apply different handover strategies and processing levels to different UE groups. HSM-mode UEs receive specialized handling with adjusted parameters, while normal-mode UEs use standard procedures, thereby improving overall network coverage efficiency without unnecessary processing complexity
Data Source
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Figure 2A
AI summary
A handover control method and apparatus for limiting handover of a User Equipment (UE) (115) from a macrocell to an underlying small cell when the UE is operating in a High Speed Mobility (HSM) mode in a radio access network (100). The UE receives an HSM pilot strength threshold offset parameter from the network and initiates (235) handover from a macrocell (105) to an underlying small cell (110) using a first pilot strength threshold value when the UE (115) is operating in a standard mode. The UE initiates (205, 215, 235) the handover using a second pilot strength threshold value when the UE (115) is operating in HSM mode. The second pilot strength threshold value is equal to the first pilot strength threshold value modified by the HSM pilot strength threshold offset parameter.