ahawkins
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Hi there. I am trying to get an idea on how data performance is measured over a trunked digital radio system. I came across this information on some technical website. It is listed below, talking about a given message model, and was wondering if this was a valid method of testing a digital/data system. The table is also listed in an attached file as well. I was also curious if there were any other methods of testing data system performance on a trunked system, that are used by the major vendors (ie Motorola, MA/COM, LTR, etc). I am trying to get an idea of how this is done in the industry, to include in a paper that I am putting together on digital radio systems. Thanks.
Using raw data bit rate to compare data systems can be very misleading. The actual system performance depends on a variety of factors including the protocol efficiency, signaling conditions, system loading, and the particular application being used. The true measurement of a public safety data system is the number of users the system can support with specific applications. This information is typically provided in a message model similar to the one shown below. By requiring each vendor to define the number of users a channel can support with a specified message model, a customer can make a true comparison of the data system’s performance.
Example Message Model for Law Enforcement.
Message Inbound (to Base) Outbound (to Mobile)
Bytes msg/usr/hr Bytes msg/usr/hr
Login 253 1 185 1
LP Inquiry 193 5 256 5
Email with
Confirmation 386 3 212 3
DL by Number 186 2 225 2
DL by Name 162 2 232 2
Changing Status 148 6 52 6
Changing Status
Broadcast 10 chan 0 0 148 60
CAD Query 196 5 226 5
Log out 172 1 74 1
CAD-to-car 50 1 200 1
Field Report 7000 0.5 3000 0.5
Mug shot 250 0.5 7000 0.5
AVL 40 12 75 12
Using raw data bit rate to compare data systems can be very misleading. The actual system performance depends on a variety of factors including the protocol efficiency, signaling conditions, system loading, and the particular application being used. The true measurement of a public safety data system is the number of users the system can support with specific applications. This information is typically provided in a message model similar to the one shown below. By requiring each vendor to define the number of users a channel can support with a specified message model, a customer can make a true comparison of the data system’s performance.
Example Message Model for Law Enforcement.
Message Inbound (to Base) Outbound (to Mobile)
Bytes msg/usr/hr Bytes msg/usr/hr
Login 253 1 185 1
LP Inquiry 193 5 256 5
Email with
Confirmation 386 3 212 3
DL by Number 186 2 225 2
DL by Name 162 2 232 2
Changing Status 148 6 52 6
Changing Status
Broadcast 10 chan 0 0 148 60
CAD Query 196 5 226 5
Log out 172 1 74 1
CAD-to-car 50 1 200 1
Field Report 7000 0.5 3000 0.5
Mug shot 250 0.5 7000 0.5
AVL 40 12 75 12
