Main Page » History » Version 45

Cuadro, Juan Pablo, 11/27/2014 05:18 PM

1 34 Cuadro, Juan Pablo
h1. Satellite Channel Emulation
2 35 Cuadro, Juan Pablo
3 19 Cuadro, Juan Pablo
----
4 19 Cuadro, Juan Pablo
5 20 Cuadro, Juan Pablo
This is the Wiki page for the SCS 2014/2015 project #1. It deals with DVB-S2 and its novel ACM feature.
6 20 Cuadro, Juan Pablo
7 38 Cuadro, Juan Pablo
h2. Table Of Contents
8 38 Cuadro, Juan Pablo
9 38 Cuadro, Juan Pablo
# [[Main Page|Introduction]]
10 38 Cuadro, Juan Pablo
# [[DVB-S2]]
11 38 Cuadro, Juan Pablo
# [[Lab Setup]]
12 38 Cuadro, Juan Pablo
## [[Link Emulator]]
13 38 Cuadro, Juan Pablo
## [[Newtec EL470]]
14 44 Cuadro, Juan Pablo
### [[FlexACM Functionality]]
15 38 Cuadro, Juan Pablo
### [[EL470 Configuration]]
16 38 Cuadro, Juan Pablo
### [[Measurement Capabilities]]
17 45 Cuadro, Juan Pablo
### [[Information Sources]]
18 38 Cuadro, Juan Pablo
19 19 Cuadro, Juan Pablo
h2. Progress
20 19 Cuadro, Juan Pablo
21 25 Cuadro, Juan Pablo
+@Tasks:@+
22 19 Cuadro, Juan Pablo
23 24 Cuadro, Juan Pablo
* %{background: none}@Introduction Section:@%
24 24 Cuadro, Juan Pablo
** %{background: lightgreen}@Why ACM is necessary.@%
25 27 Cuadro, Juan Pablo
** %{background: lightgreen}@Block diagram of ACM functionality.@%
26 36 Cuadro, Juan Pablo
27 24 Cuadro, Juan Pablo
* %{background: none}@DVB-S2 Section:@%
28 24 Cuadro, Juan Pablo
** %{background: yellow}@A little bit of history.@%
29 24 Cuadro, Juan Pablo
** %{background: yellow}@Features vs DVB-S.@%
30 24 Cuadro, Juan Pablo
** %{background: yellow}@Coding and modulation schemes.@%
31 36 Cuadro, Juan Pablo
32 1 Cuadro, Juan Pablo
* %{background: none}@Test Setup Section:@%
33 36 Cuadro, Juan Pablo
** %{background: yellow}@Introduction EL470:@%
34 36 Cuadro, Juan Pablo
*** %{background: yellow}@Modem configuration, ethernet bridge. Explain as in manual (both modems on same subnet, etc...)@%
35 36 Cuadro, Juan Pablo
** %{background: yellow}@Introduction Link Emulation system@%
36 29 Cuadro, Juan Pablo
** %{background: lightgreen}@Network diagram of full setup@%
37 23 Cuadro, Juan Pablo
** %{background: lightgreen}@Single diagram for each modem and associated client PC@%
38 1 Cuadro, Juan Pablo
** %{background: yellow}@Full settings for modems (ACM mode as well as CCM mode)@%
39 1 Cuadro, Juan Pablo
** %{background: yellow}@Table with IPs@%
40 19 Cuadro, Juan Pablo
41 25 Cuadro, Juan Pablo
+@ColorReference:@+
42 21 Cuadro, Juan Pablo
* %{background: Lightgreen}@Task 1, Status: DONE@%
43 21 Cuadro, Juan Pablo
* %{background: yellow}@Task 2, Status: TODO@%
44 1 Cuadro, Juan Pablo
** %{background: Red}@SubTask 1, Status: URGENT@%
45 21 Cuadro, Juan Pablo
46 37 Cuadro, Juan Pablo
h2. Introduction
47 19 Cuadro, Juan Pablo
48 8 Cuadro, Juan Pablo
Satellite systems based on the DVB-S standard are inevitably forced to adhere to fixed MODCOD parameters, that is, a fixed coding rate and modulation scheme. This in turn leaves the designer with no choice other than to dimension the system for the worst-case propagation conditions in order to have link-closure and meet availability, coverage and performance requirements. 
49 5 Cuadro, Juan Pablo
50 5 Cuadro, Juan Pablo
This approach has the disadvantage that high margins in the carrier-to-noise-and-interference ratios (CNIRs) occur in the majority of cases when propagation conditions allow for it. In the case of broadcasting services, where we have a multitude of users spread over very large areas, this waste of power cannot be easily avoided. However, in point-to-point links if a return channel is present it is possible to report channel state conditions and exploit its temporal variations by adapting the code rate and modulation scheme being used so as to best match the CNIR. This way a fixed link is avoided and considerable improvements in system capacity are obtained with better utilization of power resources.
51 5 Cuadro, Juan Pablo
52 5 Cuadro, Juan Pablo
The DVB-S2 standard introduces adaptive coding and modulation (ACM) enabling better use of transponder resources when high carrier-to-noise-plus-interference ratios occur due to favorable propagation conditions. ACM allows for different coding rates and modulation schemes to be used and dynamically changed on a frame-by-frame basis.
53 1 Cuadro, Juan Pablo
54 5 Cuadro, Juan Pablo
!{width: 70%}acmLink.png(Block diagram of an ACM DVB-S2 link.)!
55 1 Cuadro, Juan Pablo
56 31 Cuadro, Juan Pablo
(Similar to fig12 in "ETSI-TR.102376":http://webapp.etsi.org/WorkProgram/Report_WorkItem.asp?WKI_ID=21402&curItemNr=1&totalNrItems=1&optDisplay=10&titleType=all&qSORT=HIGHVERSION&qETSI_ALL=&SearchPage=TRUE&qETSI_STANDARD_TYPE=%27TR%27&qETSI_NUMBER=102376&qINCLUDE_SUB_TB=True&qINCLUDE_MOVED_ON=&qSTOP_FLG=N&qKEYWORD_BOOLEAN=OR&qCLUSTER_BOOLEAN=OR&qFREQUENCIES_BOOLEAN=OR&qSTOPPING_OUTDATED=&butExpertSearch=Search&includeNonActiveTB=FALSE&includeSubProjectCode=FALSE&qREPORT_TYPE=SUMMARY)