MS_ID (1-4 bit field)
An MS_ID is assigned to a mobile station for a given MBMS radio bearer with an uplink feedback channel. The length of the MS_ID field is defined by the value, increased by 1, of the Length Indicator of MS_ID field, whose value is defined by a 2 bit field (range 1 to 4). The sum of the length of the MBMS Bearer Identity field and of the length of the MS_ID field is equal to 5, i.e. the length of the TFI field.

The MS_ID field is encoded as a binary number.

Range:

1 bit field 0 to 1

2 bit field 0 to 3

3 bit field 0 to 7

4 bit field 0 to 15