1

013

1

Type

2

0 to 2¹⁶-1

2

Length

Total size in bytes.

3

0 to 2³²-1

4

Source ID

The unique identifier of the transmitting station, as described in § 2.4, Annex 1.

4

0 to 2³²-1

4

Destination ID

The unique identifier of the receiving station, as described in § 2.4, Annex 1.

5(1)

0

1

Session ID

Session ID of data session.

6

0 to 2¹⁶-1

2

ACK/NACK mask 0

When a packet was not received, then its corresponding bit should be set to one to not acknowledge the packet.

Each ACK/NACK mask corresponds to a data transfer session that started with a Start Fragment and ended with an end fragment. If the start fragment is not received, then the least significant bit is set.

The first continuation fragment corresponds with the next bit, and so on, with the end fragment being represented by the last bit. If there were 10 fragments and the end fragment was not received, then the ACK/NACK mask should be logically or-ed with 0x0200.

ACK/NACK mask 2 represents the latest TDMA frame received directly before this message response.

ACK/NACK mask 1 represents the second to last TDMA frame received.

ACK/NACK mask 0 represents the third to last TDMA frame received.

7

0 to 2¹⁶-1

2

ACK/NACK mask 1

8

0 to 2¹⁶-1

2

ACK/NACK mask 2

9

0-255

1

CQI

Received channel quality indicator averaged over the last TDMA frame received as defined in § 1.2.8, Annex 2.

10

0-255

1

ACM or EDN

0: Maintain link ID.

1: Increment link ID (higher rate)

2: Decrease link ID.

3: End delivery notification.

The link ID may only be changed if all the fragments have been successfully received and the ACK/NACK mask is set to 0. Changing the link ID should not change the channel bandwidth.

11

0-255

1

Power setting

0: Maintain power level

1: Increase power level (reserved for future use).

2: Decrease power level (reserved for future use).

Notes:

The ACK/NACK message will be transmitted in the data signalling channels on the same logical channel as defined by the “logical channel Rx” assigned by the resource allocation (#4).

During short addressed message transmissions, the ACK/NACK message will be transmitted on the RAC.

(1)   Session ID is reserved for future use.