Abstract: A method including transferring a device ID through a first communication channel between a device and a transaction device, configuring the device to send secured information in response to receiving a transaction request and sending user information to a service provider through a second communication channel in response to receiving a request to authenticate the secured information.

Abstract: A method including transferring a device ID through a first communication channel between a device and a transaction device, configuring the device to send secured information in response to receiving a transaction request and sending user information to a service provider through a second communication channel in response to receiving a request to authenticate the secured information.

Abstract: A linear transmitter (101) using predistortion includes a modulator (103), a predistorter (107), a digital quadrature modulator (111), an upconverter (113), a power amplifier (115), and an antenna (117). In addition, the transmitter (101) has a feedback loop including a coupler (119), a downconverter (123), a digital quadrature demodulator (125), and a trainer (131). The digital data to be transmitted is provided into the modulator (103), which converts the digital data into in-phase and quadrature component signals. The in-phase and quadrature component signals are then provided to the predistorter (107), which "predistorts" the component signals prior to amplification. The digital quadrature modulator (111) converts the component signals into a single analog signal. The upconverter (113) upconverts this signal from the predistorter (107) into the desired frequency of transmission, which is provided to the power amplifier (115) and the antenna (117) for amplification and broadcast.