Ebem Framing Unit; Dmd2050E Information Throughput Adpatation (Ita); Embedded Channel; Stanag Turbo Coding - Comtech EF Data DMD-2050E Installation And Operation Manual

DMD2050E Universal Satellite Modem
3.8

Ebem Framing Unit

The DMD2050E EBEM framing Unit provides the ability to multiplex both Serial (MIL-STD-188-
114A or Hgh Speed Serial Interface – HSSI) with Bridged Ethernet payload, overhead and
embedded channel data within the over-the-air transport stream.
3.8.1

DMD2050E Information Throughput Adpatation (ITA)

Refer to Appendix I for additional information.
3.8.2

Embedded Channel

The embedded channel is used for exchanging messages between DMD2050E units. ITA,
AUPC and TRANSEC traffic encryption/decryption key negotiation are typical examples of
messages sent through the DMD2050E embedded channel. The nominal rate of the embedded
channel is 4 kbps.
3.9

STANAG Turbo Coding

The DMD2050E provides STANAGE Turbo coding FEC for all specified baseband data rates (64
kbps to 52.0 Mbps) and modulation formats (BPSK, QPSK, 8-PSK, and 16-APSK) with the
following code rates: None, 1/2, 2/3, 3/4, 7/8, or 19/20. A decoding function for all Turbo encoded
data is also provided.
Turbo codes come extremely close to achieving the absolute maximum channel capacity, in bits
per second, for a given transmit power level. For traffic that can tolerate decoding delay and
require a low Bit Error Rate (BER) (i.e., 1×10–10), Turbo coding can be used. For traffic such as
speech, where excessive decoding delays cannot be tolerated and higher BER can be tolerated.
MN-DMD2050E Revision 2
STANAG Turbo Block Sizes
Block Size (Bits) Total Composite Data Rate
1024 Data Rate =<1024 kbps
4096 1024 kbps < Data Rate < 4096 kbps
16384 Data Rate 40 6 kbps
Theory of Operation
3–20