Discussion on vdl mode 4-receiver rejection performance
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- 1Introduction
- 2Rejection mask definition
- 2.1AM-DSB rejection
- 2.2VDL4 rejection
- 2.3VDL2 REJECTION
- 3Reference papers
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AERONAUTICAL MOBILE COMMUNICATIONS PANEL (AMCP) Working Group B St Petersburg, Russia 26 – 29 August 2002 Discussion on VDL Mode 4-receiver rejection performance Agenda item: Presented by EUROCONTROL Prepared by Bertrand DESPERIER SUMMARY The VDL mode 4 interference testing campaign that has been done by Eurocontrol in June and July 2002 shows that it is not possible to achieve spectrum-efficient frequency planning assignments with a SARPs and MOPS compliant VDL mode 4 radio on the basis of current AMCP WG B operational scenarios. The main limitation is due to the impact of voice DSB-AM interfering the VDL mode 4 receiver. In fact even if the radio under test fulfills the SARPs rejection requirements, these are not stringent enough to insure a satisfactory interference protection to the victim Mode 4 radio. Therefore a rejection ‘mask’ for VDL mode 4 is proposed for discussion in this paper as one possible improvement for VDL 4 frequency planning. This could become an additional MOPS requirement to protect VDL Mode 4 against any other service recognized by AMCP WGB operational scenarios. 1IntroductionThis papers extends the reflection and analysis of VDL 4 interference testing presented in [1]. It appears clearly in [1] and [2] that to achieve ground scenarios-compatible separation distance when AM-DSB is the victim and VDL the undesired signal with S/P 6dB or 12dB, 4 guard-band channels are necessary. The reverse case for VDL 4 victim of an adjacent AM-DSB interference presently constitutes a problem for VDL 4 frequency planning. The present paper introduces for discussion a possible improvement of VDL 4-receiver rejection performance. This improvement would deliver comparable separation distance around the 5th adjacent channel when looking at an AM undesired signal rejection by a VDL victim receiver.
The crucial point for an efficient receiver rejection mask is to define precisely what has to be rejected, i.e. what kind of modulation scheme, for which desired and undesired channel load… A different rejection ‘mask’ or performance could better be defined for each type of signal to be protected from. 2.1AM-DSB rejectionA typical speech signal with a peak modulation depth of 90% is equivalent to a 30% modulated 1kHz tone. It is then recommended to use 1KHz modulated 30% to measure the rejection capability of a VDL radio instead of a pure carrier in order to be as close as possible to real cases. It is recommended to ensure 68 dB rejection with the fifth channel when –88 dBm minimum signal strength is considered (i.e. a maximum interfering power of –20 dBm) or 62 dB rejection when –82 dBm minimum signal strength is considered. 2.2VDL4 rejectionThe maximum mobile channel load should be 6,67% (i.e. 5 slots/s). The interferer GFSK should fulfill the AMCP transmitter spectrum mask. It is recommended to ensure 64 dB rejection with the second channel and above when –88dBm minimum signal strength is considered (i.e. a maximum interfering power of –24 dBm) or 58 dB rejection when –82 dBm minimum signal strength is considered. 2.3VDL2 REJECTIONThe maximum mobile channel load should be 2% (i.e. 26ms pulsed every 1,3 s). The interferer D8PSK should fulfill the AMCP spectrum mask. It is recommended to ensure 66 dB rejection with the second channel and above when –88dBm minimum signal strength is considered (i.e. a maximum interfering power of –22 dBm) or 60 dB rejection when –82 dBm minimum signal strength is considered. 3Reference papers[1] Bertrand Desperier, Nikos Fistas, Patrick Delhaise “VDL4 interference tests results” AMCP WGB St Petersburg 25-30 August 2002. [2] B. Roturier, Patrick Delhaise, Bertrand Desperier, “New VDL Mode 2 test results and frequency planning criteria proposal” AMCP/WG-B, Montreal, 29 Aug –07 Sept 2001. [3] Patrick Delhaise, Bertrand Desperier, B. Roturier “Proposed modifications to the ground-ground interference scenario” AMCP/WG-B, Montreal 29 Aug –07 Sept 2001. [4] B. Roturier, Patrick Delhaise, “Some further explanations on EUROCONTROL proposed method to assess frequency planning criteria” AMCP/WG-B/IP 8-2; Rio de Janeiro, Jan. 2000. [5] B. Roturier, Patrick Delhaise, Bertrand Desperier, “Ground-ground propagation attenuation applicability to VHF frequency planning criteria”, AMCP/WG-B, San Diego 15-23 January 2001. Directory: safety -> acp -> Inactive%20working%20groups%20library Inactive%20working%20groups%20library -> Acp wgc6/WP24 aeronautical communications panel (acp) working group c meeting 6 Toulouse, France October 20-24, 2003 Inactive%20working%20groups%20library -> Acp working group b meeting Inactive%20working%20groups%20library -> Amcp/wg c-wp/11 aeronautical mobile communications panel Inactive%20working%20groups%20library -> Aeronautical communications panel (acp) Inactive%20working%20groups%20library -> Working Group C Inactive%20working%20groups%20library -> International Civil Aviation Organization working paper Inactive%20working%20groups%20library -> Aeronautical communications panel (acp) Inactive%20working%20groups%20library -> Aeronautical mobile communications panel(amcp) Working Group n networking Inactive%20working%20groups%20library -> 7th Meeting Atlantic City, New Jersey Mar 7 Download 12.6 Kb. Share with your friends:
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