MBMS Cell Reselection via Service Area Identity Lists
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Solution Overview
Problem
User Equipment (UE) in idle or connected states face challenges in camping on Multimedia Broadcast Multicast Service (MBMS) cells that provide the services they are receiving or interested in, and in identifying when these services start to be broadcast, leading to potential service disruptions and inefficient resource allocation.
Innovation Solution
A method and system that enable UE to receive and process service area identity lists from base stations to prioritize cell reselection based on available MBMS services, and for base stations to communicate service identities to neighboring cells to facilitate seamless handovers and service detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE sets the highest priority to MBMS frequency for cell reselection, then UE can camp on MBMS cells providing desired services, but UE may perform unnecessary cell reselections and increase network load when services are not actually broadcast
Solution Approach 1:
The patent applies preliminary action by having the network proactively notify UEs about upcoming MBMS service broadcasts through MCCH change notifications before the services are actually broadcast. This allows UEs to prepare for cell reselection in advance rather than reacting to service disruptions, thereby maintaining service continuity while avoiding unnecessary reselections and reducing network load.
2Measurement precision
If UE monitors MCCH change notification to detect service start, then UE can detect when MBMS services start to be broadcast, but UE cannot accurately detect service start if camping on non-MBMS cells
Solution Approach 1:
The patent uses MCCH change notification as an intermediary mechanism that is broadcast by MBMS cells and can be received by UEs regardless of their current camping status. This intermediary allows UEs to detect service start information even when not camping on MBMS cells, maintaining both detection accuracy and camping flexibility.
Solution Approach 2:
The system implements feedback by having MBMS cells broadcast MCCH change notifications that provide information about upcoming service broadcasts. This feedback loop allows UEs to stay informed about service availability without needing to camp on MBMS cells, resolving the contradiction between detection accuracy and camping flexibility.
3Loss of energy
If MBMS services are transmitted synchronously over MBSFN, then frequency resources are saved and spectrum usage rate is improved, but service area coverage is limited to specific MBSFN areas
Solution Approach 1:
The patent applies universality by enabling MBMS services to be accessed by UEs across multiple cell types (MBMS cells and non-MBMS cells) through the broadcast of MCCH change notifications. This allows the same MBMS service to be available in a broader geographic area than a single MBSFN area while maintaining synchronous transmission efficiency.
Data Source
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AI summary
The present invention discloses a method and system for reselecting or handing over to a broadcast multicast cell. The method includes the following steps: broadcasting, by an MBMS cell, a service area identity list of a service area to which the MBMS cell belongs; determining, by a UE, whether the service area identity list includes a service area identity corresponding to a service; if the service area identity list includes service area identity corresponding to the service, setting, by the UE, a cell reselection priority of a frequency of an MBMS cell to the highest. According to the present invention, a UE can identify whether a cell capable of providing services that the UE is receiving or is interested in around the UE, so that the cell can learn which neighboring cells are MBMS cells and what services are being broadcast in these MBMS cells if such MBMS cells are available.