LTE TDD Cell Switching Subframe Configuration
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Solution Overview
Problem
In LTE TDD systems, UE may fail to hand over to a destination cell due to dynamic changes in TDD UL/DL configurations after receiving a cell handover command, leading to failed random access procedures.
Innovation Solution
The UE and access network device detect dynamic TDD UL/DL configurations in the destination cell and maintain constant uplink transmission subframes during handover, ensuring accurate message delivery by determining subframes based on cell type information and configuration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the TDD UL/DL configuration is changed dynamically in the destination cell, then the traffic adaptation capability is improved, but the handover success rate deteriorates because the UE may use outdated configuration information
Solution Approach 1:
The source eNB obtains the TDD UL/DL configuration of the destination cell before initiating handover, and includes this configuration information in the handover command sent to the UE. This preliminary acquisition ensures the UE receives accurate, up-to-date configuration information before the handover executes, preventing the mismatch problem that would otherwise occur due to dynamic configuration changes in the destination cell
Solution Approach 2:
The destination eNB continuously updates its TDD UL/DL configuration based on traffic conditions and notifies the source eNB of these changes. The source eNB then provides this updated configuration information to the UE through the handover command, creating a feedback loop that ensures the UE always receives current configuration data, thereby maintaining both dynamic adaptability and handover reliability
2Productivity
If the TDD UL/DL configuration changes after the random access response is sent, then the network can adapt to varying traffic demands, but the random access procedure fails because the UE selects resources based on outdated configuration
Solution Approach 1:
The TDD UL/DL configuration information is obtained and included in the handover command before the random access procedure begins. This preliminary provision of accurate configuration data enables the UE to correctly identify uplink subframes and select appropriate random access resources, ensuring successful random access even in dynamic TDD environments where configuration changes may occur during the handover process
Data Source
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AI summary
A method and device for cell switching are disclosed. The method includes: according to the indication of a cell switching command sent by an access network equipment, a user equipment determines the subframe for uplink transmission in the cell switching process, herein the transmission direction of the subframe for uplink transmission in the cell switching process does not change in the cell switching process; in the process of switching to a target cell, the user equipment sends a message, which is used for switching to the target cell, to the access network equipment by using the determined subframe. In the embodiment of the invention, in the process of a UE handing over to a target cell, because the transmission direction of the subframe for uplink transmission does not change, the message, which is used for switching to the target cell and sent by the UE with the subframe. for uplink transmission, can be correctly received by the access network equipment, thereby the success ratio of a UE handing over to a target cell is improved.