| 摘要 |
An arrangement for cancelling an echo returning to a first mobile station (MS1) from a second mobile station (MS2). The arrangement comprises tandem free operation (TFO) and an acoustic echo canceller (AEC) to which criteria have been defined, upon fulfillment of which the echo canceller replaces an uplink speech signal of the second mobile station (MS2) by comfort noise (CN) in a second coding format. In accordance with the invention, the echo canceller (AEC) generates additional information (AI) if the tandem free operation (TFO) is active and if criteria for replacing the speech signal with the comfort noise are fulfilled at the same time. In response to said additional information (AI), a first transcoder (TRAU1) encodes the speech signal to be transmitted to the first mobile station (MS1) by using the comfort noise (CN) that is generated by the echo canceller (AEC) and that is in the second coding format. |
