Control of echo cancellers in a telecommunication system
AssigneeNokia Corporation
InventorJari Eikkula
Life of this patent
Estimating the term…
Abstract
The invention relates to a communications network, including switching centers having no echo canceling equipment and switching centers having echo canceling equipment. The switching centers are capable of changing the call party or the call during the call. The switching center which controls the change of call party or call type is arranged to command the nearest switching center having the echo canceling capability to connect/disconnect an echo canceling equipment to/from the connection. In other words, in these special situations the echo cancellation is controlled by a new signaling feature within the communications network.
Claims17
A method for controlling echo canceling in a telecommunications network comprising a first switching center having no echo canceling equipment and at least one second switching center having echo canceling equipment, said method comprising
- establishing a call connection in a speech mode via said first switching center and said at least one second switching center so that the echo canceling equipment is connected to the connection,
- changing, under control of said first switching center, the type of call connection from the speech mode to another transmission mode in which echo canceling is not allowed,
- sending to said at least one second switching center from said first switching center a signaling message commanding said second switching center to disconnect the echo canceling equipment from the connection,
- changing, under control of said first switching center, the type of the call connection from said other transmission mode back to the speech mode, and
- sending to said at least one second switching center from said first switching center a signaling message commanding said second switching center to connect the echo canceling equipment to the connection.
A method for controlling echo canceling in a telecommunications network comprising a first switching center having no echo canceling equipment and at least one second switching center having echo canceling equipment, said method comprising
- establishing a call connection in a speech mode via said first switching center and said at least one second switching center so that the echo canceling equipment is connected to the connection,
- changing under control of said first switching center, the type of call connection from the speech mode to another transmission mode in which echo canceling is not allowed, and
- sending to said at least one second switching center from said first switching center a signaling message commanding said second switching center to disconnect the echo canceling equipment from the connection,
- wherein said telecommunications network is a mobile communications network, said first switching center is a mobile switching center, and said at least one second switching center is a gateway mobile switching center connecting said mobile communications network to a fixed telephone network.
A communications network, comprising a first switching center having no echo canceling equipment and at least one second switching center having echo canceling equipment, said first switching center being configured to be capable of changing the call party during the call by releasing a connection leg to an old party and establishing a new connection leg to a new party, and wherein
- the first switching center is configured to send, in response to the change of call party, to said at least one second switching center a signaling message commanding said second switching center to connect the echo canceling equipment to a call connection, when there is no echo canceling equipment already connected to the call connection and echo canceling is required due to the new party.
A communications network comprising a first switching center having no echo canceling equipment and at least one second switching center having echo canceling equipment, said first switching center being configured to be capable of changing the call type from a speech mode to another transmission mode during the call, and wherein
- the first switching center is configured to send, in response to said change of call type from said speech mode to said other transmission mode, to said at least one second switching center a signaling message commanding said second switching center to disconnect the echo canceling equipment from a call connection, when said call connection is routed via said second switching center.
A switching center for a communications network, wherein
- the switching center echo canceling equipment is capable of changing the call party during the call by releasing a connection leg to an old party and establishing a new connection leg to a new party, and
- the first switching center is configured to send, in response to the change of call party, to a second switching center having echo canceling equipment a signaling message commanding said second switching center to connect the echo canceling equipment to a call connection, when there is no echo canceling equipment already connected to the call connection and echo canceling is required due to the new party.
A switching center for a communications network, wherein
- the switching center without echo canceling equipment is capable of changing the call type from a speech mode to another transmission mode during the call, and
- the switching center is configured to send, in response to said change of call type from said speech mode to said other transmission mode, to a second switching center having echo canceling equipment, a signaling message commanding said second switching center to disconnect the echo canceling equipment from a call connection, when said call connection is routed via said second switching center.
Dependencies are inferred from the claim text.