Subject: [NEXTEL-1] P25 Conventional Digital

From: Marcel <[email-masked]>
Date: Mon, 28 Oct 2002 15:29:28 -0500

------ Original Message --------
From: "[email-masked]" <[email-masked]>
Subject P25 Conventional Digital

Stan, 
Motorola have a  software feature called "Mobile Voting". It is 
available in the Astro P25 portfolio and in MCS2000/MTS2000 
analog radios. It is RSS programmable. It will solve your issue.

Background:
It was originally developed for Australian Police forces many years 
ago. It is now being used worldwide including the US. They use a 
Multi-cast system configuration to achieve wide area coverage. (i.e.  
a number of base stations on different frequencies transmitting 
the same audio from different base sites - Base Rx signals are 
processed via SpectraTAC/ DigiTAC /AstroTAC prior to 
re-transmission). The mobiles and the portables then 
automatically select the "best site*" by way of a smart 
scanning/voting algorithym based on RSSI levels. Receiver Attack 
time is  about 300mSec ..so no worse than  usual squelch delays. 

Operationally, these MultiCast  Auto Scan groups are slaved to 
mode positions  on the radios channel selector. From the actual 
users perspective, it is just like selecting/talking on any other 
conventional channel and thus zero additional training.

It works extremely well for analog, digital and Securenet Systems. 
(DVP/DES work better than the DVP/DES-XL series due to their 
asynchronous nature of the former) and at a much lower cost than 
Single freq simulcast....ofcourse you need the available 
spectrum...which from your memo, seems is not an issue here.

Your local Mot Sales rep may not know of the feature but either get 
hold of the RSS to validate yourself or make them check back with 
the product guys in Schaumburg and you should have your 
problem resolved.

(*Best site  is not necessarily the site with the absolute strongest 
signal but one that first meets the "very strong" signal criteria. This 
is done as a compromise to help minimize receiver unsquelch 
time and besides if you have a 10-50uV signal it does not matter 
where it is coming from..ie operationally the officer hears a clean 
intelligible message from the despatcher or fellow officer.)

best regards
Martin Cahill
Regional Director
Wireless Pacific Ltd
website: www.wirelesspac.com

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