This ASM message is used to return message acknowledgments to one or more addressed messages. Note that this message should always use Link ID of 5 (3/4 coding rate). Acknowledgement message is defined in Table 31.
Table 31
Acknowledgment message
|
Parameter |
Number of bits |
Description |
|---|---|---|
|
Message ID |
4 |
5 – Multiple acknowledgment message with no communication state. |
|
Retransmit flag |
1 |
0 (reserved for future use). |
|
Repeat indicator |
2 |
Used by the repeater to indicate how many times a message has been repeated. 0 – 3; 0 = default; 3 = do not repeat any more. |
|
Session ID |
6 |
The Session ID associates the VDL transmission with a specific PI transaction. |
|
Source ID |
32 |
The Unique Identifier of the transmitting station as described in § A1‑2.4. |
|
Destination ID |
32 |
The Unique Identifier of the receiving station as described in § A1-2.4. |
|
ACK/NACK mask |
16 |
Specifies which MITDMA block identifiers failed. Bit map field with the LSB representing Block identifier 0, up to the 15th bit representing Block identifier 14. “1” indicates a packet failed. “0” indicates the packet was received ok. The MSB (16th bit) is not used and should be set to “0”. |
|
Coding rate adaption request |
2 |
0 (reserved for future use). |
|
Channel quality indicator |
8 |
Signal quality. |
|
Zero padding |
1 slot: N/A / 153 |
Padding bits are added as required to complete the block size. These bits are not available for future use. |