GSCN (global synchronization channel number)

Global Synchronization Channel Number (GSCN) is a term used in 5G cellular networks to define the channelization of the Global Synchronization Signal (GSS) and the Primary Synchronization Signal (PSS). It is a frequency-domain parameter that specifies the channel center frequency of these signals in the 5G New Radio (NR) system.

In 5G NR, there are two types of synchronization signals, GSS and PSS, that are used by the mobile devices to synchronize with the base station. The GSS is a periodic signal that is transmitted by the base station to allow the mobile device to synchronize its timing with the network. The PSS is a non-periodic signal that is used by the mobile device to identify the physical cell identity of the base station.

To transmit these synchronization signals, the 5G NR system uses a set of resource blocks (RBs) that are defined by the subcarrier spacing (SCS). The SCS defines the spacing between the subcarriers in the frequency domain and is specified as a multiple of the basic subcarrier spacing (15 kHz) in the 5G NR system. The SCS can be 15 kHz, 30 kHz, 60 kHz, or 120 kHz, depending on the deployment scenario.

The GSCN is used to determine the channel center frequency of the GSS and PSS signals in the 5G NR system. The GSCN is defined as an integer value that is calculated based on the channel center frequency (in GHz) and the SCS. The formula to calculate the GSCN is as follows:

GSCN = floor ((channel center frequency - 0.05 GHz) / SCS)

Where floor() is the floor function that rounds down to the nearest integer.

For example, if the channel center frequency is 3.5 GHz and the SCS is 60 kHz, the GSCN can be calculated as follows:

GSCN = floor ((3.5 GHz - 0.05 GHz) / 60 kHz) = floor (58.25) = 58

Therefore, the GSS and PSS signals would be transmitted on the resource blocks that correspond to GSCN 58 in this scenario.

The GSCN is an important parameter in the 5G NR system because it enables the mobile devices to quickly synchronize with the base station and identify the physical cell identity. By using a standard channelization scheme based on the GSCN, the mobile devices can easily detect the synchronization signals and determine the channel center frequency of the base station.

The GSCN is also important for the network operators because it allows them to configure the synchronization signals in a consistent and predictable manner across the network. This ensures that the mobile devices can easily synchronize with the network and reduces the likelihood of synchronization failures or interference issues.

In summary, the GSCN is a frequency-domain parameter that specifies the channel center frequency of the Global Synchronization Signal (GSS) and the Primary Synchronization Signal (PSS) in the 5G NR system. It is calculated based on the channel center frequency and the subcarrier spacing and is used to enable quick synchronization and identification of the physical cell identity. By using a standard channelization scheme based on the GSCN, the network operators can ensure consistent and predictable synchronization across the network.