MBMS Paging for Group Communications Latency Reduction
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Solution Overview
Problem
Current group communications systems face delays and packet loss in real-time applications like Push-To-Talk (PTT) due to the existing paging procedures, especially when client nodes transition from idle to connected mode using unicast transmission.
Innovation Solution
A method involving a control node that transmits a paging message on an MBMS bearer to speed up the client node's transition to connected mode, allowing for faster packet reception, by modifying the signaling flow to reduce latency and improve resource efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unicast transmission is used for paging client nodes in idle mode, then the client node can be reached reliably, but the call setup delay and mouth-to-ear delay increase significantly
Solution Approach 1:
The patent combines unicast and MBMS transmission methods into a hybrid paging approach. The control node first sends a paging indication via unicast to wake up the client node, then immediately follows with the actual paging message via MBMS broadcast. This merging allows reliable delivery (unicast) while reducing delay (MBMS), as the client node can process the paging message faster when already awake and the same message is broadcast to multiple nodes simultaneously.
Solution Approach 2:
The patent applies preliminary action by sending a paging indication message before the actual paging message. The unicast paging indication is sent first to wake up the client node from idle mode, preparing it in advance to receive and process the subsequent MBMS paging message more quickly. This preliminary wake-up action reduces the overall delay compared to waiting for the client node to naturally wake up during its periodic listening cycle.
2Productivity
If MBMS resources are allocated to serve all groups, then resource efficiency improves, but there may not be sufficient MBMS resources available for all groups
Solution Approach 1:
The patent applies partial action by using unicast transmission only for the paging indication phase rather than for the entire paging process. The actual paging message is sent via MBMS broadcast to multiple client nodes simultaneously, utilizing MBMS resources partially (only for the message payload) while using unicast resources minimally (only for the initial indication). This partial use of each transmission type optimizes overall resource efficiency.
Solution Approach 2:
The patent segments the paging process into two distinct phases: (1) paging indication sent via unicast to wake up individual client nodes, and (2) paging message sent via MBMS broadcast to deliver the actual information. This segmentation allows different resource allocation strategies for each phase, using reliable unicast resources for wake-up and efficient MBMS broadcast resources for information delivery, thereby optimizing overall resource utilization.
3Use of energy by moving object
If client nodes listen periodically for paging information, then energy consumption is reduced, but the average wake-up time increases to half the paging cycle
Solution Approach 1:
The patent applies preliminary action by sending the paging indication via unicast before the actual paging message via MBMS. The client node wakes up slightly earlier to receive the unicast indication, which tells it when to expect the MBMS message. This preliminary notification allows the client node to wake up just in time for the MBMS broadcast rather than waiting for the next periodic paging opportunity, reducing average wake-up time while maintaining energy efficiency.
Solution Approach 2:
The patent implements feedback by having the client node acknowledge receipt of the paging indication and provide status information about its connection state. The control node uses this feedback to determine whether to send paging messages via unicast or MBMS, and to optimize the timing and resource allocation for subsequent paging operations. This feedback mechanism allows dynamic adjustment to minimize both delay and energy consumption.
Data Source
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AI summary
There is provided mechanisms for paging at least one client node in a group communications system. A method is performed by a control node of the group communications system. The method comprises obtaining a need for paging the at least one client node in the group communications system. The method comprises transmitting a paging message for the at least one client node on a multimedia broadcast multicast service (MBMS) bearer to the at least one client node. There is also provided a control node configured to perform such a method. There is also provided mechanisms for receiving paging in a group communications system.