Multimedia Broadcast Multicast Service Delivery Method

Description

The MBMS delivery method is a concept in the 3GPP Multimedia Broadcast Multicast Service (MBMS) architecture that defines the mechanism used by an MBMS user service to deliver content. It specifies how the content is transported over the network, leveraging MBMS bearers and associated procedures. The delivery method is a key component of the MBMS user service, which is the service offered to end users, such as mobile TV, live streaming, or file download. The delivery method determines the transport characteristics, such as whether the content is delivered via download or streaming, and it may involve additional procedures like file repair or reception reporting.

Architecturally, the MBMS delivery method is implemented through a combination of network elements and protocols. The Broadcast Multicast Service Center (BM-SC) is responsible for the overall management of the MBMS user service, including the selection of the appropriate delivery method. The BM-SC interacts with the MBMS Gateway (MBMS-GW) and the eNodeBs (or gNodeBs) to establish the necessary MBMS bearers. The delivery method itself is defined in specifications such as 26.237, 26.346, 26.852, 26.946, and 26.947, which describe the protocols and procedures for different types of delivery, such as download delivery, streaming delivery, and group communication delivery.

The operation of an MBMS delivery method involves several key procedures. First, the BM-SC determines the delivery method based on the characteristics of the content and the requirements of the user service. For example, a file download may use the download delivery method, which involves the transmission of files over MBMS bearers and may include forward error correction (FEC) and file repair procedures to ensure reliable delivery. A live video stream may use the streaming delivery method, which involves the real-time transmission of media over MBMS bearers with appropriate QoS. The BM-SC then initiates the session start procedures to establish the MBMS bearers, and the content is delivered to the UEs according to the selected delivery method. The delivery method may also include procedures for reception reporting, which allow the network to collect feedback from UEs about the quality of the delivery.

The MBMS delivery method provides significant benefits for delivering content efficiently to many users. By selecting the appropriate delivery method, the network can optimize the use of resources and ensure that the content is delivered with the required quality. For example, the download delivery method can use FEC and file repair to ensure that all users receive the complete file, even in the presence of packet loss. The streaming delivery method can use adaptive bitrate techniques to adjust the quality based on network conditions. The delivery method also enables the network to support a wide range of services, from simple file downloads to complex multimedia streaming, and it is a key enabler for services like mobile TV, live streaming, and public safety communications.

In summary, the MBMS delivery method is a mechanism used by an MBMS user service to deliver content, utilizing MBMS bearers and associated procedures. It is defined in 3GPP specifications such as 26.237, 26.346, 26.852, 26.946, and 26.947, and it has evolved across releases to support new features and capabilities. Its flexibility and efficiency make it a vital component of 3GPP networks for delivering multicast and broadcast services.

Purpose & Motivation

The MBMS delivery method was created to provide a standardized way for MBMS user services to deliver content efficiently over mobile networks. Before its introduction, delivering content to multiple users required individual unicast connections, which was inefficient and could lead to network congestion. The MBMS delivery method solves this problem by defining specific mechanisms for content delivery that leverage MBMS bearers, which allow the network to share resources among many users. This not only conserves bandwidth but also reduces the processing load on the core network and radio access network.

Historically, the need for efficient content delivery in mobile networks became apparent with the rise of mobile TV and multimedia services. The MBMS delivery method was first introduced in 3GPP Release 8, building on the earlier MBMS concepts from Release 6. It provided a way to deliver content using MBMS bearers, with different methods for different types of content, such as download and streaming. Over time, the delivery method has evolved to support new features, such as file repair, reception reporting, and group communication, and it has been adapted for use in LTE and 5G networks.

The MBMS delivery method also addresses the need for efficient group communication in mission-critical scenarios. In public safety networks, for example, first responders need to receive the same information simultaneously, and the MBMS delivery method ensures that this is done reliably and efficiently. Furthermore, the MBMS delivery method supports the delivery of emergency alerts to all users in a specific area, which is essential for public warning systems. By providing a standardized mechanism for content delivery, the MBMS delivery method enables operators to offer new services and generate additional revenue, while ensuring that network resources are used optimally.