Terminal Mobility State Estimation in Heterogeneous Small Cell Networks
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Solution Overview
Problem
In mobile communication systems, especially with the deployment of small cells, there is a lack of effective measures for managing terminal mobility and reestablishing connections promptly when transitioning between idle and connected states, leading to frequent handover failures and mobility management issues.
Innovation Solution
A method and apparatus for estimating terminal mobility states by receiving and calculating system information, storing, and transmitting mobility state information to a base station, along with a reestablishment procedure for reconnecting to unprepared small cells, which includes transmitting a reestablishment request message and managing mobility history information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small cells are deployed to increase system throughput and fill coverage holes, then system throughput and coverage are improved, but handover failure rate increases due to frequent handovers in small cell service areas
Solution Approach 1:
The terminal estimates its mobility state in advance during idle state by calculating mobility state information based on system information received from the serving cell. This preliminary mobility state estimation allows the terminal to prepare appropriate handover parameters before actually performing handover, thereby reducing handover failure rate while maintaining small cell deployment benefits for system throughput
2Reliability
If mobility state estimation is performed accurately during state transition, then handover management is improved, but additional signaling overhead and processing complexity are introduced
Solution Approach 1:
The terminal autonomously performs mobility state estimation by itself during idle state using system information already received for other purposes. The terminal calculates mobility state information based on available system information, stores it, and transmits it to the base station during connection establishment, without requiring additional network-side estimation mechanisms or complex coordination, thus improving handover management while minimizing added complexity
3Speed
If connection reestablishment is performed promptly to unprepared small cells, then mobility continuity is improved, but connection stability may be compromised due to lack of handover status information
Solution Approach 1:
The terminal provides feedback to the base station by transmitting the estimated mobility state information during connection establishment. This feedback allows the base station to make informed decisions about connection acceptance or rejection, balancing the need for rapid reestablishment with connection stability. The base station can use this mobility state information to determine whether to accept or reject the reestablishment request, ensuring stable connections while maintaining fast reestablishment capability
Data Source
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AI summary
The present invention pertains to a method and device for preserving mobility information in terminal state transition and effectively re-accessing in a heterogeneous cell network in a mobile communication system. A method for estimating a mobility state of a terminal in a mobile communication system according to one embodiment of the present invention may comprise the steps of: receiving, by the terminal, system information from a serving cell during an idle state; calculating mobility state information by using the received system information; storing the mobility state information; and transmitting the mobility state information to a base station when the terminal is connected to the base station. According to one embodiment of the present invention, when an idle state of a terminal is changed to a connection state in a mobile communication system, a mobility state of the terminal can be more effectively estimated.