One or more systems and/or methods for identifying a positional state of a mobile device are provided. An output audio pulse may be generated from a speaker of a mobile device. An input audio pulse, corresponding to the output audio pulse, may be detected utilizing a microphone of the mobile device. The output audio pulse and the input audio pulse may be evaluated to determine a positional feature associated with the mobile device. The positional feature may be evaluated using a classifier to identify a positional state of the mobile device (e.g., the mobile device may be laying on a table, inside a user's jacket pocket, within a vehicle, etc.). In an example, an operating characteristic of the mobile device may be adjusted based on the positional state of the mobile device (e.g., a ringer volume may be increased, a content recommendation may be displayed, etc.).