NOISE-ADAPTIVE COMMUNICATIONS SIGNAL GAIN

摘要

A communications device employs noise-adaptive transmit signal gain that takes echo cancellation into account so that a remote listener engaged in conversation with a local user of the communications device is not subjected to overly loud received voice when the local user experiences high ambient noise. Because the noise environment for the local user comprises not only local background noise, but also noise received through the communications device from the remote user, the communications device employs echo cancellation to ensure the transmit signal gain adaptations are not erroneously influenced by remote noise. A gain associated with the transmit signal is adjusted based on estimated noise, with the noise estimate taking the effects of echo cancellation into account. By decreasing transmit signal gain in response to increasing local noise, the communications device may compensate for the increasing speech volume of the local user generally caused by an increase in local noise. In order to avoid abrupt, noticeable gain adjustments, the communications device may employ hysteresis between the noise level at which the transmit gain is reduced and the noise level at which it is increased. Further, the communications device may adjust transmit signal gain incrementally over a defined time period. Optionally, the communications device may increase receive signal gain in tandem with decreasing transmit signal gain, such that overall transmit/receive loop gain remains relatively constant.