Just to clarify something to start, NAV CANADA is not a majority shareholder in Iridium Communications Inc., but rather Aireon LLC (the provider of space-based ADS-B service). The Aireon payload is a "hosted" on each of Iridium's NEXT satellites.
NAV CANADA has completed its Aeronautical Study for a Canadian ADS-B Out Performance Requirements Mandate and the Aeronautical Study Plan Summary is available publicly. The current plan includes the first two phases of the mandate:
- Phase 1: Class A airspace (which includes 18,000ft ASL to FL600 in the Sourthern Control Area, FL230 to FL600 in the Northern Control Area, and FL270 to FL600 in the Arctic control area)
- Phase 2: Class B airspace (All low level controlled airspace above 12,500ft ASL or from the minimum enroute altitude, whichever is higher, to below 18,000ft ASL plus some terminal control areas or control zones)
While not quoted in the study summary, Phase 1 is proposed for implementation January 1, 2021 and Phase 2 on January 1, 2022. Beyond Phase 2, no sooner than January 1, 2023, Class C, D and E airspace as required and following additional stakeholder consultations.
To you comment about "seeing" other traffic, the current infrastructure is not set up to re-transmit traffic information for ADS-B "In" equipped aircraft. Based on the Technical Specification, Aireon only detects up the "Out" transmission from 1090 MHz Mode S transponders but is unable to detect 978 MHz UAT transponders.
So all that to say, unless you're flying above 12,500ft ASL, the ADS-B Mandate will not be affecting you for at least a few years and you will not be seeing ADS-B data coming from the Aireon constellation, only the ADS-B broadcasts from other aircraft directly in the vicinity. There is no ground infrastructure in Canada which broadcasts TIS-B or FIS-B data so you will not see aircraft equipped with Mode C only.