Target Base Station Uplink Grant Timing for Wireless Handover
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Solution Overview
Problem
Wireless communication systems face challenges in maintaining seamless connectivity during handovers from one base station to another, particularly when user equipment moves between coverage areas, leading to potential disruptions in ongoing sessions.
Innovation Solution
A method involving a target base station receiving a handover request from a source base station, generating an uplink grant, and communicating it to the user equipment through the source base station, along with a starting time adjusted for subframe offset, to facilitate a smooth handover by transmitting a handover complete message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If handover is performed without uplink grant timing synchronization, then handover speed is improved, but communication reliability deteriorates due to potential message loss
Solution Approach 1:
The target base station pre-calculates and determines the starting time for uplink grant validity by accounting for the subframe offset between source and target base stations before the handover is executed. This preliminary timing synchronization ensures that the user equipment can successfully transmit the handover complete message without timing conflicts, thereby maintaining communication reliability while enabling fast handover.
2Reliability
If uplink grant validity period is extended to ensure message delivery, then communication reliability is improved, but latency increases
Solution Approach 1:
The patent dynamically adjusts the starting time parameter of the uplink grant validity period based on the calculated subframe offset between source and target base stations. By precisely setting the starting time rather than extending the validity period, the system ensures reliable message delivery within the minimum necessary time window, thus avoiding increased latency while maintaining communication reliability.
3Reliability
If timing synchronization is implemented with subframe offset compensation, then session integrity is improved, but system complexity increases
Solution Approach 1:
The target base station acts as an intermediary that calculates the subframe offset between source and target base stations and uses this offset to determine the appropriate starting time for uplink grant validity. This intermediary timing adjustment mechanism ensures session integrity during handover while keeping the implementation complexity localized to the base station's timing calculation, without requiring complex changes to the user equipment.
Data Source
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AI summary
Certain aspects of the present disclosure relate to techniques for performing handover from a source base station to a target base station. According to one aspect, a method generally includes receiving a handover request from a source base station for handover of communication of a user equipment from the source base station to the target base station, generating a scheduling uplink grant for the user equipment to transmit a handover complete message based on receiving the handover request, and communicating the grant to the user equipment.