Multi Band Cells ( MBC ) in GSM

Multi Band Cells (MBC)

A multi band network consists of cells from different frequency bands for example: 900/1800 MHz

−By combining these frequencies in the same cell with 1 common BCCH, the radio performance and traffic capacity are improved where the no. of cells and

-Using MBC concept with only 1 BCCH, this will reduce the no. of defined neighbors to 50% leading to better accuracy for the measurement reports coz there will be more time available for measurements for each neighbor.

-The Dynamic OL/UL subcells (Concentric cells) is a prerequisite feature for the Multi Band Cells.

−Mostly the frequency band with “Better coverage” (i.e. lower frequency band) is configured as the Underlaid subcell while the other frequency band with “Worse coverage” (i.e. higher frequency band) is configured as the Overlaid Subcell.

−Ex: 900MHz frequency band UL, while 1800MHz frequency band OL

−It is recommended to select the BCCH frequency to lie in the “Better Coverage” i.e. UL subcell.

−for the previous example then BCCH frequency will belong to the 900MHz band

−A parameter CSYSTYPE defines the band of the used BCCH frequency in a multi band cell.

−A parameter BAND defines the band of the Channel Group, where the channel group consists of no. of frequencies as will be seen later.

−As mentioned before, the path loss/Distance to cell border/time advance criteria will define the coverage limit of the frequency band used in the OL subcell vs. UL subcell, (In this case the OL&UL will belong to two different bands)

−Also the traffic load can be maintained between the two subcells (that belong to two different bands) using the subcell load distribution feature where the SCLDSC parameter will define which subcell is preferred first.