Real-Time RF Channel Impairment Emulator

The Joint Tactical Radio System (JTRS) program has need of a programmable and extensible wireless channel impairment emulator accommodating networks of 8 to 100 radio nodes operating in a frequency range of 2 MHz to 2 GHz. The emulator should be high fidelity, broadband, have a range resolution of 0.25 km, provide link losses of up to 130 dB, have a resolution of 0.5 dB, a high dynamic range, good isolation between radios, low minimum latency, and be capable of propagation delays of up to 1 second. In addition, the system should be able to handle multiple protocols, support systems that are full duplex, multiple-input multiple-output (MIMO), and frequency agile. It should be capable of accepting pre-programmed scenarios involving Doppler shifts, fast and slow fading, and multipath. Toyon proposes to meet these requirements with a unique design capable of full duplex operation over a wide bandwidth. Our design uses wide band hybrid couplers in the RF front end combined with a digital front end utilizing a signal spectrum detector to control a digital down converter (DDC) to reject transmit energy from the receive path. Also, we plan to use highly efficient filter designs in the field programmable gate array (FPGA) that will allow us to emulate a large number of the channels implicit in a large radio network.