LTE Cell Handover Pre-Resource Allocation
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Solution Overview
Problem
The existing cell handover procedures in LTE systems experience significant data transmission interruptions, with an average time of 50 ms, which is not sufficient for applications like online video and real-time gaming that require interruptions within 20 ms to 25 ms, as the current methods disrupt data transmission between the user equipment (UE) and the source eNB during the handover process.
Innovation Solution
A cell pre-handover method is introduced, where the UE sends a measurement report to the eNB when signal quality conditions are met, allowing for pre-handover instructions to prepare resources for a seamless handover without interrupting current communication, including sending a random access preamble and establishing radio bearers, enabling a quicker handover process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the traditional cell handover procedure is used, then the handover decision is made after measuring neighboring cell signal strength, but data transmission interruption time increases to 50 ms
Solution Approach 1:
The patent applies preliminary action by initiating resource preparation at the target eNB before the actual handover execution. The source eNB sends a handover request message to the target eNB in advance, allowing the target eNB to allocate resources and prepare configuration information before the UE needs to switch cells, thereby reducing interruption time.
Solution Approach 2:
The handover procedure is segmented into distinct phases: resource preparation phase (handover request and acknowledgment exchange between eNBs), execution phase (handover command to UE), and completion phase (handover confirm message). This segmentation allows resource preparation to occur independently and in parallel with UE measurements, reducing overall handover time.
2Speed
If resource preparation is performed during ongoing communication, then handover speed increases, but coordination between source eNB and target eNB becomes more complex
Solution Approach 1:
The source eNB acts as an intermediary that coordinates between the target eNB and the UE. It sends the handover request to the target eNB, receives the handover acknowledgment with resource allocation information, and then forwards the handover command to the UE. This intermediary role simplifies the coordination complexity by providing a centralized control point.
Solution Approach 2:
The target eNB provides feedback to the source eNB through the handover acknowledgment message, confirming resource availability and providing allocation details. This feedback mechanism allows the source eNB to make informed decisions about handover timing and to communicate accurate resource information to the UE, enabling faster handover execution.
Data Source
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AI summary
Embodiments of the present invention disclose a cell handover method and system, and a device. The method includes: after receiving a pre-handover instruction sent by a first eNB, sending, by UE, a random access preamble, and establishing, based on configuration information in the pre-handover instruction, a radio bearer corresponding to a second eNB; and receiving, by the UE, a timing advance used by the UE to perform uplink synchronization with the second eNB and an uplink indication message used to indicate an uplink resource used when the UE communicates with the second eNB. It can be learned that in the embodiments of the present invention, resource preparation can be performed for a cell handover in advance in a process of communication between the UE and a current cell.