LTE Handover CSI-RS Forwarding for CoMP Activation
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Solution Overview
Problem
In LTE networks, the effectiveness of the radio link between a UE and the network is reduced after handover due to the delay in initiating CoMP, resulting in a decrease in downlink data transfer rate until CoMP can be reconfigured at the target eNB.
Innovation Solution
A method where the UE generates and sends a measurement report including CSI-RS results to the source eNB during handover, allowing the target eNB to initiate CoMP immediately by including these results in the handover request, enabling it to configure transmission points without waiting for subsequent measurement data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the UE sends measurement reports to the source eNB and the target eNB waits for subsequent measurement data after handover, then the handover procedure is simple and follows standard protocols, but the CoMP activation is delayed and downlink data transfer rate decreases
Solution Approach 1:
The source eNB includes CSI-RS measurement results from the UE in the handover request message sent to the target eNB before handover is completed. This preliminary action provides the target eNB with necessary measurement data in advance, enabling immediate CoMP activation without waiting for subsequent measurement reports, thus resolving the contradiction between procedural simplicity and data transfer rate.
2Ease of operation
If the target eNB requests CSI-RS measurement results from the UE after handover, then the measurement procedure follows standard protocols, but there is a delay in CoMP activation and radio link effectiveness is reduced
Solution Approach 1:
The source eNB acts as an intermediary by collecting and forwarding the UE's CSI-RS measurement results to the target eNB through the handover request message. This intermediary action eliminates the time delay that would occur if the target eNB waited for the UE to send measurement reports after handover, while still maintaining standard measurement procedures.
3Reliability
If the target eNB waits for UE measurement data after handover, then the system follows standard measurement reporting procedures, but the radio link effectiveness is reduced and CoMP cannot be initiated immediately
Solution Approach 1:
The measurement results are obtained and included in the handover request before handover is finalized. This preliminary acquisition of measurement data ensures that the target eNB has reliable measurement information immediately available for CoMP activation, resolving the contradiction between maintaining reliable standard procedures and achieving immediate productivity.
Data Source
AI summary
A method of handing over a mobile terminal from a source base station to a target base station in a Long Term Evolution, LTE, compliant mobile wireless communications network. The method comprises generating a measurement report including one or more channel state information reference signal, CSI-RS, measurement result at a mobile terminal. The mobile terminal sends the measurement report to a source base station. The source base station determines either in response to the measurement report or separately that the network should handover the mobile terminal to a target base station. The source base station sends a handover request to the target base station. The handover request sent from the source base station to the target base station includes at least one CSI-RS measurement result received from the mobile terminal such that the target base station can initiate coordinated multi-point transmission, CoMP, to the mobile terminal upon handover.