TS4000 Radio Modem User’s Manual
AirNet Packet Protocol
54
Total Packet Time = Attack Time + Packet Transmit Time + Decay Time
Packet Transmit Time = Packet Length / Channel Rate
Packet Length = (Data Bits + Overhead Bits)
x Framing Overhead x Coding Overhead
= (Data Bits + 112) x 1.1 { x 1.5 }
Overhead Bits = 14 bytes x 8 bits per byte = 112 bits
Framing
Overhead
=
1.1
Coding
Overhead
(optional)
=
1.5
Packet Timeout = Relay Delays for Data Packet
Packet Timeout
+ Ack Packet Delay at Destination Node
+
Relay
Delays
for
ACK
Packet
Where:
Relay Delays for Data Packet = Relay #1Data Packet Delay
+ Relay #2 Data Packet Delay
...
...
+ Relay #Y Data Packet Delay
Relay #Y Data Packet Delay = Decay Time
+ (Y x Slot Time)
+ Attack Time
+ Data Packet Transmit Time
Data Packet Transmit Time = Data Packet Length / Channel Rate
Data Packet Length = (Data Bits + Overhead Bits)
x Framing Overhead x Coding
Overhead
Overhead Bits = 14 bytes x 8 bits per byte = 112 bits
Framing
Overhead
=
1.1
Coding
Overhead
(optional)
=
1.5
ACK Packet Delay at Destination Node = Decay Time
+ Attack Time
+ ACK Packet Transmit Time
Relay Delays for ACK Packet = Relay #1ACK Packet Delay
+ Relay #2 ACK Packet Delay
...
...
+ Relay #Y ACK Packet Delay
Relay #Y ACK Packet Delay = Decay Time
+ (Y x Slot Time)
+ Attack Time
+ ACK Packet Transmit Time
ACK Packet Transmit Time = ACK Packet Length / Channel Rate
ACK Packet Length -Uncoded = 16 bytes x 8 bits per byte = 128 bits
-Coded
=
128
bits
x
1.5
=
192
bits
Decay Time = Tx Decay Time + Additional Transmit Attack Time
Attack Time = Tx Attack Time + Additional Transmit Attack Time
