9.1.47 Uplink free

3GPP44.018GSM/EDGE Radio Resource Control (RRC) protocolMobile radio interface Layer 3 specificationRelease 17TS

This message is sent on the main DCCH, in unacknowledged mode using the RR short protocol discriminator by the network to inform the mobile station of the uplink status of the voice group call channel. See table 9.1.47.1. The message indicates the uplink as free unless it is used by the network to request the mobile station to perform an uplink reply procedure.

Message type: UPLINK FREE

Significance: dual

Direction: network to mobile station

Table 9.1.47.1: UPLINK FREE message content

<UPLINK FREE> ::= < RR short PD : bit > — See 3GPP TS 24.007
< message type : bit(5) > — See 10.4
< short layer 2 header : bit(2) > — See 3GPP TS 44.006
< Uplink Access Request bit >
{ L | H < Uplink Identity Code bit(6) >}
{ null | L — Receiver compatible with earlier release

| H — Additions for Release-7

{ 0|1 <Emergency_Ind: bit(1)>}

}

< spare padding > ;

Uplink Access Request :

L Mobile station shall not perform the uplink reply procedure;
H Mobile station shall perform the uplink reply procedure.

Uplink Identity Code :

This field is coded as the binary representation of the UIC.

If provided by the network, the Uplink Identity Code shall be used by the mobile for the coding of the UPLINK ACCESS message

Emergency_Ind:

This field indicates the status of the emergency mode for the group call.

0 Emergency mode not set.

1 Emergency mode set.

If Emergency_Ind is not present in the message, then it is assumed that the emergency mode is not set and talker priority is not supported by the network.