P25 Phase 2 Forum
Impact on coverage design
By on Monday, September 26th, 2011 at 10:32am.
What is the impact of transitioning from Phase I to Phase II on coverage design, especially in simulcast configuration. I hear conflicting opinions as to whether any negative impact is to be expected. I would appreciate some well researched engineering arguments rather than just opinions.
Comments:
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commented on Tuesday, September 27th, 2011 at 2:19am.
New Jersey, Phase II is really too new for the Land mobile market to provide great information. However, the best place for information on design comes from the cellular industry, which has used TDMA for the last 10 years. Recieve is affected more than transmit (as usual) and diversity recieve is employed to combat small fades. I will look to see what references I have
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commented on Tuesday, September 27th, 2011 at 3:51am.
The limiting factor for LMR has always been portable talk back. This will result in the need for a different approach to the network design. Will it mean more sites, the use of DAS and BDA as well as vehicular repeaters?
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commented on Tuesday, September 27th, 2011 at 7:55pm.
Won't In Vehicular repeaters be easier to impliment on a TDMA system?
You won't need to have two radio bodies if you can RX on one timeslot, and then TX on the next using same body.
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commented on Wednesday, October 5th, 2011 at 1:51pm.
Can some form of voting or corrected, reclocked data from a receiver-only site be implemented for Phase II, so we can put in fill-in sites where portable coverage is deficient but talk-out is sufficient, or are we locked into a whatever receives has to transmit philosophy here?
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commented on Monday, October 10th, 2011 at 3:22pm.
I think you'll find the answer varies depending on the current configuration and design of your Phase 1 system. Have you tried running a coverage simulation of your system in the Phase 2 mode or asking your vendor to run it for you? Outbound simulcast delay spread in H-DQPSK is the biggest challenge with Phase 2. The coverage model will show if it is an issue in your case or not.
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