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MOB_MSHO-REQ Mobile Station Handover Request message

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The MOB_MSHO-REQ message is a signaling message used in cellular communication systems to initiate a handover of a mobile station (MS) from one base station (BS) to another. In this response, we will explain the MOB_MSHO-REQ message, its purpose, and the procedures involved in a handover in mobile networks.

Background

Mobile networks are made up of a number of cells, each served by a base station (BS). The cells are designed to cover a specific geographic area and provide wireless communication services to mobile stations (MS) such as mobile phones, tablets, and other portable devices. As the MS moves, it may cross the boundaries of cells and the signal quality from the serving BS may deteriorate. In such cases, the MS may need to switch to another BS in order to maintain the quality of the communication. This process is known as handover.

Handover is a critical aspect of mobile communication systems, as it ensures seamless communication even when the MS is on the move. Handover can be initiated by either the MS or the network, depending on the type of handover. In network-initiated handover, the network decides to switch the MS to a different BS based on the signal quality or other factors such as network load. In MS-initiated handover, the MS detects that the signal quality is deteriorating and requests a handover to a different BS.

MOB_MSHO-REQ Message

The MOB_MSHO-REQ message is used by the MS to request a handover to a new BS. The message is sent from the MS to the serving BS, which forwards it to the target BS. The message includes information about the current serving BS, the target BS, and the MS.

The MOB_MSHO-REQ message is a part of the Mobile Application Part (MAP) protocol, which is used in the signaling between the MS and the network. The MAP protocol is implemented in the Signaling System 7 (SS7) network, which is used in many cellular networks around the world.

The MOB_MSHO-REQ message contains the following information:

  1. IMSI (International Mobile Subscriber Identity) of the MS
  2. Serving BS Cell Identity (CI)
  3. Target BS CI
  4. Timing Advance (TA)
  5. List of neighboring BSs and their CIs
  6. Quality of Service (QoS) requirements
  7. Handover Type (Soft handover, hard handover, etc.)

The IMSI is a unique identifier that is used to identify the MS in the network. The serving and target BS CIs are used to identify the current and target cells. The TA is used to compensate for the time delay between the MS and the BS, which can vary depending on the distance between them. The list of neighboring BSs and their CIs is used by the network to determine the best target BS for the handover. The QoS requirements specify the minimum level of service quality that the MS requires, such as the data rate, delay, and error rate. The handover type specifies whether the handover should be soft or hard, depending on the network configuration.

Handover Procedure

When the serving BS receives the MOB_MSHO-REQ message, it checks the information in the message and decides whether to initiate a handover or not. If the serving BS decides to initiate a handover, it sends a HO-REQ message to the target BS, requesting it to allocate resources for the handover. The HO-REQ message contains information about the MS and the current serving BS.

The target BS receives the HO-REQ message and checks whether it can allocate resources for the handover. If the target BS can allocate resources, it sends a HO-ACK message to the serving BS, indicating that the resources are available. The serving BS then sends a HO-COMPL message to the MS, instructing it to switch to the target BS.

During the handover process, the MS maintains connections with both the serving BS and the target BS, allowing the transfer of data and signaling messages between the two. This is known as soft handover. In contrast, hard handover involves a complete break in the connection with the serving BS before connecting to the target BS.

After the handover is completed, the MS sends a MOB_HO_COMPLETE message to the new serving BS, confirming that the handover has been successful. The serving BS then sends a HO-ACK message to the target BS, indicating that the handover has been completed.

Conclusion

In conclusion, the MOB_MSHO-REQ message is a signaling message used in mobile communication systems to initiate a handover of a mobile station from one base station to another. The message contains information about the current serving BS, the target BS, and the MS, including the IMSI, CIs, TA, neighboring BSs, QoS requirements, and handover type. The handover procedure involves a series of messages between the MS, serving BS, and target BS, culminating in the handover of the MS to the new BS. Handover is a critical aspect of mobile communication systems, allowing seamless communication even when the MS is on the move.