Multicast Late Joining via Device-to-Device Data Forwarding
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Solution Overview
Problem
Current wireless communication protocols, such as LTE, do not allow late joining devices to receive missing data from a multicast group, leading to inefficiencies in spectrum usage and reassembly challenges for the device.
Innovation Solution
Implementing a method where a late joining device can join a multicast group and receive the missing data via device-to-device communication, allowing the network to save on spectrum usage by avoiding retransmission of the same data to original group members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network retransmits missing data to late joining devices via traditional multicast or unicast, then the late joining device can receive complete data, but spectrum efficiency deteriorates due to redundant transmissions to original group members
Solution Approach 1:
The patent introduces an intermediary approach where original multicast group members act as intermediaries to forward missing data portions to late joining devices. Instead of the network entity directly retransmitting data, existing members who already have the data serve as intermediaries, enabling efficient peer-to-peer data sharing that avoids redundant network transmissions.
Solution Approach 2:
The patent implements a copying mechanism where the network entity creates indicators pointing to data portions already transmitted to original group members. These indicators reference existing data copies held by group members, allowing late joiners to obtain data through direct copying from members rather than requiring new network transmissions.
2Reliability
If the network transmits complete data sets to all multicast members including late joiners, then all devices have complete data, but transmission time increases due to retransmitting already-sent data
Solution Approach 1:
The patent segments the data transmission process by dividing the complete data set into multiple portions and tracking which portions have been transmitted. The network entity maintains indicators that identify specific data portions already sent to original members, allowing selective transmission only of missing portions to late joiners rather than retransmitting the entire data set.
Solution Approach 2:
The patent applies preliminary action by having the network entity pre-transmit data portions to original group members before late joiners arrive. Indicators are prepared in advance to identify which data portions are available, enabling immediate efficient data transfer to late joiners upon their arrival without requiring complete retransmission.
3Device complexity
If traditional multicast protocols are used without late joining support, then protocol simplicity is maintained, but device adaptability deteriorates as late joining devices cannot receive missing data
Solution Approach 1:
The patent enhances protocol universality by enabling the multicast mechanism to serve multiple functions: it supports both original group members and late joining devices within the same protocol framework. The extended protocol allows devices to join at any time and receive appropriate data portions, making the system adaptable to different joining scenarios without requiring separate protocols.
Solution Approach 2:
The patent introduces dynamic elements to the protocol that allow it to adapt to changing group compositions. The system dynamically identifies late joining devices, determines which data portions they need based on indicators, and facilitates selective data transfer. This dynamic adaptation enables the protocol to handle variable joining times while maintaining operational simplicity.
Data Source
AI summary
A method is provided for facilitating multicast service. The method may include receiving data multicast to members of a multicast group. The method may further include determining, based at least in part on an indication received during multicast of the data, that a late joining device has joined the multicast group subsequent to initiation of the multicast. The method may additionally include marking, based at least in part on the received indication, a point at which the late joining device began to participate in the multicast. A corresponding apparatus and computer program product are also provided.