ND SatCom SKYWAN IDU 7000, Manual

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2010-10-26 Network Design and Engineering Guide 59
General Carrier Design
TDMA Carrier Design with ’TDMA Calculator’
Table 2-3 Summary ’General Data Input’ Parameter
2.6.2 Section ’Data Input per Frequency Channel’
The parameters have to be specified for each Sky WAN
®
carrier. Please find the parameter de-
scriptions below:
’Modem data rate [kbit/s]’: The channel’s information rate excluding error correction bits and
synchronization patterns. For a detailed discussion of this quantity refer to the preceeding
chapter 2.5.
’Modem data rate’, ’Modulation Scheme’, ’Code rate’ and ’BER’: define the channel coding,
modulation and the maximum acceptable bit error rate of this carrier. With these parameters
the tool will calculate the required symbol rate and frequency bandwidth. Note, that the calcu-
lated results for Eb/No and Es/No values have to be proved against a link budget calculation,
which will be discussed in the chapter 3.5.
User traffic composition fields: For each carrier the composition of the user traffic can be
specified. There are 6 different traffic types possible:
- ’1- FR Voice’: Frame Relay Voice (Voice over Sky WAN
®
FAD). Select the appropiate
Codec or protocol used.
- ’2 - FR Realtime’: Frame Relay Real-time
- ’3 - FR Non-Realtime’: Frame Relay Non Real-time
- ’4 - VoIP’: Voice over IP
- ’5 - IP Realtime’: IP Real-time
- ’6 - IP Non-Realtime’: IP Non Real-time
For each traffic type the ’Average packet length [byte]’ and the fraction of the total user traffic
Number of downlink popula-
tions Master stations transmits TDMA and network information in the ref-
erence burst to all stations on a defined carrier. All stations receiving
the reference burst on the same carrier belong to the same 'Downlink
Population (DPL)'.
Max. quantity of stations configured in one DL is 255.
- MRB mode: max quantity of DLP is 8 (dependent on the
quantity of frequency channnels configured).
- MRB-DUB mode: 7
- NFB-DUB mode: 1
Size superframe (max) [TD-
MA frames] Superframing allows to split and distribute the slaves request bursts
to several TDMA frames, thus saving capacity for data.
Value range of 1 to 16.
Roll-off factor The roll-off factor basically gives the distance between two carriers
needed for sufficient interference suppression. Select
- 0.2
- 0.3
- 0.4
Parameter Name Definition