FACCH (Fast Associated Control Channel)

Introduction:

In a cellular communication network, the Fast Associated Control Channel (FACCH) is a channel that is used for transmitting urgent signaling messages between the mobile station and the base station. The purpose of the FACCH is to quickly transmit important control information, such as handover requests, channel activation, and deactivation, without waiting for the next available traffic channel.

In this article, we will discuss the working of the FACCH, its types, and its advantages in detail.

Working of FACCH:

The FACCH is a type of signaling channel that is dynamically assigned when required. It is used for urgent messages that need to be transmitted immediately, such as handover requests, channel activation, and deactivation. The FACCH is a separate channel that is established in parallel to the traffic channel. It uses the same radio frequency and time slot as the traffic channel but operates at a higher priority.

The FACCH is a voice codec that uses a modified version of the regular speech codec. The voice codec used in the FACCH is designed to transmit control information quickly and reliably. The FACCH is capable of transmitting information at a higher rate than the traffic channel, which allows it to transmit urgent messages quickly.

Types of FACCH:

There are two types of FACCH channels:

Slow Associated Control Channel (SACCH)

The SACCH is a signaling channel that is used to transmit control information related to the radio link between the mobile station and the base station. The SACCH is established when the mobile station is connected to the network and is used to transmit information such as signal strength, timing advance, and power control. The SACCH operates at a lower priority than the traffic channel and is used for non-urgent messages.

Fast Associated Control Channel (FACCH):

The FACCH is a signaling channel that is used to transmit urgent control information between the mobile station and the base station. The FACCH is established when urgent messages need to be transmitted, such as handover requests, channel activation, and deactivation. The FACCH operates at a higher priority than the traffic channel and is used for urgent messages.

Advantages of FACCH:

The FACCH has several advantages over the SACCH and regular traffic channel:

Fast Transmission of Urgent Messages:

The FACCH is designed to quickly transmit urgent control information between the mobile station and the base station. This allows the network to respond quickly to changes in the radio environment, such as handover requests or channel activation, without waiting for the next available traffic channel.

Efficient Use of Radio Resources:

The FACCH uses the same radio frequency and time slot as the traffic channel but operates at a higher priority. This means that the network can efficiently use its radio resources to transmit both voice and control information without affecting the quality of service.

Improved Call Quality:

The FACCH allows the network to quickly respond to changes in the radio environment, which improves call quality and reduces call drop rates. The fast transmission of control information helps the network to maintain a stable connection between the mobile station and the base station, which improves call quality and reduces the likelihood of dropped calls.

Conclusion:

The Fast Associated Control Channel (FACCH) is an essential signaling channel in cellular communication networks. It is used to quickly transmit urgent control information between the mobile station and the base station. The FACCH operates at a higher priority than the traffic channel and uses the same radio frequency and time slot as the traffic channel, which allows the network to efficiently use its radio resources. The FACCH improves call quality, reduces call drop rates, and allows the network to respond quickly to changes in the radio environment.