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MCCH (MBMS control channel)

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MBMS (Multimedia Broadcast Multicast Service) is a service that allows the transmission of multimedia content such as video, audio, and data to multiple users simultaneously over a cellular network. The MBMS control channel (MCCH) is a dedicated channel used to deliver control information associated with MBMS.

In this article, we will provide an in-depth explanation of MCCH, its functions, and its role in the MBMS system.

Overview of MBMS

Before we dive into MCCH, let's first understand the basics of MBMS. MBMS is a point-to-multipoint service that allows the efficient delivery of multimedia content to multiple users simultaneously. The service is designed to support a wide range of applications, including mobile TV, video streaming, and file downloads.

MBMS is based on the IP multicast technology, which allows a single packet to be delivered to multiple recipients at the same time. In the MBMS system, the content provider sends the multimedia content to the MBMS center, which in turn distributes the content to the MBMS gateways. The MBMS gateways then transmit the content to the mobile devices that have requested the content.

The MBMS system comprises two types of channels: the MBMS point-to-multipoint (PTM) bearer channels and the MBMS control channels.

MBMS Control Channel (MCCH)

The MBMS control channel (MCCH) is a dedicated channel used to deliver control information associated with MBMS. The MCCH is used to transmit information related to the MBMS session, such as session start and stop times, content availability, and the identity of the MBMS service.

The MCCH is a shared channel, which means that multiple MBMS sessions can use the same MCCH. The MCCH uses the same transport mechanism as the PTM bearer channels, which allows it to share the same radio resources as the PTM bearer channels.

The MCCH can be divided into two sub-channels: the scheduling sub-channel and the notification sub-channel.

Scheduling Sub-Channel

The scheduling sub-channel is used to transmit scheduling information related to the MBMS session. This includes the start and stop times of the session, the identity of the MBMS service, the number of PTM bearer channels associated with the session, and the mapping between the PTM bearer channels and the MBMS service.

The scheduling sub-channel is used by the mobile device to obtain information about the available MBMS sessions and the associated PTM bearer channels. The mobile device can then use this information to request the desired content from the MBMS gateway.

The scheduling sub-channel is transmitted periodically by the MBMS center, and the mobile device must monitor the channel to receive the scheduling information.

Notification Sub-Channel

The notification sub-channel is used to transmit information related to the content availability of the MBMS session. This includes information about new content that has become available and the content that is about to expire.

The notification sub-channel is used by the mobile device to receive information about the available content and to determine which content to request from the MBMS gateway.

The notification sub-channel is transmitted by the MBMS gateway when new content becomes available or when the content is about to expire. The mobile device must monitor the channel to receive the notification information.

MCCH Operation

The MCCH operates in conjunction with the PTM bearer channels to deliver multimedia content to the mobile devices. The PTM bearer channels are used to transmit the actual multimedia content, while the MCCH is used to deliver the control information associated with the MBMS session.

When the mobile device requests a particular MBMS session, it receives the scheduling information from the MCCH. The mobile device can then use this information to request the desired content from the MBMS gateway using the PTM bearer channels.

During the transmission of the multimedia content, the MCCH is used to provide feedback to the mobile device about the status of the PTM bearer channels. This includes information about the quality of the signal and the availability of the PTM bearer channels.

The MCCH also provides information to the mobile device about the content that is available and the content that is about to expire. This allows the mobile device to proactively request the desired content from the MBMS gateway, ensuring that the content is available when the user wants to access it.

In addition, the MCCH is used to manage the resources associated with the MBMS session. This includes allocating the necessary radio resources for the MBMS session, managing the QoS (Quality of Service) of the session, and ensuring that the session operates efficiently.

The MCCH can also be used to manage the security of the MBMS session. This includes encrypting the control information transmitted on the MCCH to ensure that it is not intercepted or tampered with by unauthorized parties.

Benefits of MCCH

The MCCH provides several benefits to the MBMS system, including:

  1. Efficient resource utilization: The MCCH allows multiple MBMS sessions to share the same radio resources, reducing the amount of resources required to transmit control information.
  2. Proactive content delivery: The MCCH provides the mobile device with information about the available content, allowing the device to proactively request the desired content from the MBMS gateway. This ensures that the content is available when the user wants to access it.
  3. Improved QoS: The MCCH manages the QoS of the MBMS session, ensuring that the session operates efficiently and that the desired QoS is delivered to the user.
  4. Enhanced security: The MCCH can be used to encrypt the control information transmitted on the channel, ensuring that it is not intercepted or tampered with by unauthorized parties.

Conclusion

The MBMS control channel (MCCH) is a dedicated channel used to deliver control information associated with MBMS. The MCCH is used to transmit information related to the MBMS session, such as session start and stop times, content availability, and the identity of the MBMS service.

The MCCH operates in conjunction with the MBMS point-to-multipoint (PTM) bearer channels to efficiently deliver multimedia content to multiple users simultaneously. The MCCH provides several benefits to the MBMS system, including efficient resource utilization, proactive content delivery, improved QoS, and enhanced security.

Overall, the MCCH plays a critical role in the MBMS system, enabling the efficient delivery of multimedia content to multiple users simultaneously.