Based on the versatile MT-4E radio platform, the Daniels digital P25 voter now offers an enhanced level of functionality for conventional P25 applications.

Digital Voting System

For extended or improved coverage, multiple receivers can be installed on the same frequency. When the Subscriber Unit transmits, many (and possibly all) of the receivers may hear the transmission depending on the location of the Subscriber Unit. The voter will then determine and select the "best" received signal from all the signals received. The best signal is then rebroadcast from the base station transmitter allowing improved talk-back capability between mobiles in the field. Each local receiver?s received signal is back-hauled to the voter and transmitter base station via IP links (Microwave or wired).

As shown in the diagram below for a 3 site voted system with a single transmitter, each receiver receives the signal from the Subscriber Unit. These signals are then evaluated and compared, and the best possible representation of the signal received is passed to the Daniels P25 voter.

Digital Voting Diagram

For P25, each traffic packet received includes the Bit Error Rate (BER) detected by the receiver which is used by the voter to determine the relative quality of packets between the multiple streams received. This process is performed continuously as the quality of the received RF signal varies at each of the different receivers. An analog voice signal has no error detection; therefore the only measure of quality is the received signal strength indication (RSSI). The Daniels Voter has a "good quality threshold" which defines the analog signal quality level above which no switching will be done to reduce unnecessary switching of channels.

The Daniels Voting System is based on the versatile and proven MT-4E conventional radio system. P25 Voting requires no changes to existing MT-4E radios and is supported in all the P25 frequency bands (VHF, UHF, T-Band, 700 and 800 MHz). As shown in the diagram above, each Receiver site consists of a Daniels Receiver subrack along with the Daniels Voter. An industrial PC then receives all the voted received signals and sends the result to the transmitter site. The Industrial PC also provides the programming and System Monitoring statistics.

 

Please see the following PDF application note(s) to view more information:

P25 Voting Brochure

Daniels would be pleased to provide you with a quotation for this system. Please complete the following Quote Worksheet which will be electronically forwarded to the Daniels sales department.