ANÁLISIS DE INTERFERENCIA CO-CANAL EN SISTEMAS DVB-S

Transcription

1 ANÁLISIS DE INTERFERENCIA CO-CANAL EN SISTEMAS DVB-S CO-CHANNEL INTERFERENCE ANALYSIS IN DVB-S SYSTEMS Ing. Aurora Fernández Bezanilla Ms.C. Abdel Martínez Alonso Marzo 2013

2 ABSTRACT This presentation describes 3 experiments that characterize the DVB-S performance and ruggedness against co-channel interference. In Experiment 1 was measured the carrier to interference threshold for the reception in DVB-S system. In Experiment 2, was determined the bit error ratio threshold for a range of C/I levels in the vicinity of the threshold value obtained in the previous experiment. In Experiment 3 was determined the system response against periodic and burst signals within the operating band.

3 TOPICS Digital TV via Satellite. DVB-S standard. C/I and BER thresholds for the reception in the DVB-S system. DVB-S performance against interference noise. Experiments results.

4 Two TV by satellite distribution platforms types are mainly used for television and radio: Fixed Service Satellite (FSS), and Direct Broadcast Satellite (DBS). FSS are normally used for broadcast feeds to and from television networks and local affiliate stations, business television, videoconferencing, and commercial telecommunications. DBS is a term used to refer to satellite television broadcasts intended for home reception.

5 FSS use the C band (3.7 to 4.2 GHz), and the lower portions of the Ku bands (11.7 to 12.5 GHz). DBS use only a portion of the Ku band (11.7 GHz to 12.7 GHz). The world's first commercial satellite systems used the "C" band frequency range. But the amount of power that any C-band satellite could transmit has to be limited to a level that would not cause interference to terrestrial microwave links. The first commercial "Ku" band satellites made their appearance in the late 1970s and early 1980s. Relatively few terrestrial communications networks were assigned to use this frequency band; Ku-band satellites therefore could transmit higher-powered signals than their C-band counterparts

6

7 ETS : STANDARD DVB-S Describes the modulation and channel coding system for satellite digital multi-programme Television (TV)/High Definition Television (HDTV) services to be used for primary and secondary distribution in Fixed Satellite Service and Broadcast Satellite Service bands. Most digital satellite TV broadcasters today are using DVB-S standard. It was first published in January 1995 by the European Telecommunication Standards Institute (ETSI). What makes the DVB standard a significant development is its ability to serve as a unified standard that can be applied across a variety of distribution platforms.

8 ETS : STANDARD DVB-S

9 ETS : STANDARD DVB-S DVB-S performance against interference NO RECEPTION NO C/N > C/N threshold C/I > C/I threshold BER < BER threshold YES RECEPTION OK

10 TRANSPONDER USED IN THE EXPERIMENTS Satellite Hispasat 1D Free to Air Channel Center Frequency GHz Band Width 36 MHz

11 TV-Ro STATION TV LNB IRD

12 EXPERIMENTS SET SIGNAL GENERATOR TV LNB IRD SPECTRUM ANALYZER

13 INTERFERENCE SIGNAL Single carrier, channel frequency center. Carrier swept inside the channel BW. TV IRD SIGNAL GENERATOR LNB SPECTRUM ANALYZER

14 EXPERIMENT 1: C/I RESULTS C/I = C/N (db) C/N min (C/N threshold) C/N max (minimum loss) C/I MEASURE MIN MAX AVERAGE 19.2 C/I THEORY C/I

15 EXPERIMENT 2: BER RESULTS

16 EXPERIMENT 3: Periodic or burst signal? RESULTS 1. Periodic signal worst case t in BW salto = BW 3dB_canal DVB-S t out BER 1 = BER 2 t in 2. Burst signal BW salto < BW 3dB_canal DVB-S t out

17 CONCLUSIONS In all experiment the results were consistent with those expected.

18 Thanks!