1. A context aware system for use in a mobile device, the context aware system comprising: a context change detector (CCD) configured to receive sensor data from one or more sensors of the mobile device and to detect a change in a current context state of the mobile device based on the received sensor data without determining what a next context state of the mobile device will be, wherein the CCD is configured to detect the change in the current context state by: processing the received sensor data to generate one or more features, wherein the one or more features includes at least one feature selected from the group consisting of a mean of the received sensor data, a variance of the received sensor data, or a standard deviation of the received sensor data, and comparing the one or more features with one or more respective thresholds; and a context classifier (CCL) coupled to the CCD, wherein the CCL is configured to transition from a low power consumption mode to a normal power consumption mode in response to the CCD detecting the change in the current context state, and wherein the CCL is further configured to determine the next context state of the mobile device while in the normal power consumption mode, wherein the CCL is configured to vary the one or more respective thresholds in response to the current context state of the mobile device.