As wireless signals become more dense, modulation formats become more complicated. Project 25 time-division-multiple-access (TDMA) cellular systems with harmonized differential quadrature phase-shift-keying (H-DQPSK) modulation are an example of that trend. Testing these systems becomes even more challenging, although Aeroflex this week rolled out a solution in the form of its 3900 Series Digital Radio Test Set this week at the International Wireless Communications Expo (IWCE 2011) in Las Vegas. The demonstration involved decoding and encoding P25 TDMA signals with the test set, receiving a downlink signal from a Motorola Solutions GTR 8000 Base Station, and then transmitting an uplink signal to a Motorola APX 7000 portable radio.

According to Rob Barden, director of product marketing for Aeroflex Test Solutions, "Key to testing the new TDMA operation of base repeaters for P25 TDMA is the ability to transmit and receive the new modulation types. This testing includes the validation of key modulation fidelity parameter of the transmitter and other parameters critical to verifying proper operation in the P25 TDMA mode."

The demonstration verified that the 3900 Series Digital Radio Test Set is a suitable performance verification solution for these next-generation cellular systems.