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Showing posts with the label Codec Management

Type of BICC calls

BICC Bearer establishment procedures: Four variants of BICC IP bearer set-up procedures are defined: -             Fast Forward -             Delayed Forward -             Fast Backward -             Delayed Backward  Those procedures differ on the way the bearer control information are exchanged, and on whether an APM (Connected) message shall be sent by the originating BICC node once the bearer is ready for use. -             Bearer control information exchanges : -             In Fast bearer setup (forward or backward) and in delayed forward bearer establishment procedures, the IP bearer establishment is done in the ...

Core Network Architecture - Interfaces

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The interfaces and protocols supported towards the networks are mentioned below: Network Interfaces and Protocols

Codec Management

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Codec Management Objectives Codec Management has following goals: 1.) Optimize the voice quality. 2.) Optimize the bandwidth efficiency 3.) Optimize the transcoder resource in MGW. 4.) Optimize the delay Voice Quality: Voice quality is measured in terms of the level, attenuation, delay, echo, and so on and may be used as a basis for the iQoS assessments for conventional VoIP. Voice Quality is measured in terms of R-value and below 50 are not recommended. Standards                                     Intrinsic quality (R) ------------------------------------------------------ ITU G.711 (64kbps)                                  94.3 ITU G.728 (12.kbps)                               ...

TFO - Tandem Free Operation

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In Early legacy telephone network, A call between the two mobiles involved with two transcoding function at both the end which decrease the voice quality. The Transcoding Function done by the TRAU (Transcoding and Rate Adaptation Unit) to compress and decompress the speech.  TFO (Tandem Free Operation) enables to avoid the traditional double speech encoding / decoding in MS to MS call configurations. TFO uses in-band signalling and procedures for transcoders to enable compressed speech to be maintained between a pair of transcoders.   So the main objective of TFO is the improvement of the voice quality for calls between 2 mobile subscribers, but no resource optimisation is introduced  as transcoder functions are always present in the path. If TFO is activated between two end nodes, TFO Frames with compressed speech (e.g. AMR in LSB) as payload are carried over 8 or 16 kbit/s channels mapped onto the least or two least significant bits of the 64 kbit/s...

TrFO - Transcoder Free Operation

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In Early legacy telephone network, A call between the two mobiles involved with two transcoding function at both the end which decrease the voice quality. The Transcoding Function done by the TRAU (Transcoding and Rate Adaptation Unit) to compress and decompress the speech.  Transcoder Free Operation (TrFO) is transport of compressed speech, which eliminates unnecessary coding and decoding of the signals when both end uses the same codecs. TrFO utilizes out of band signaling capabilities that include the ability to determine the negotiated codec type to be used at the two end nodes.  If the two end nodes are capable of the same codec operations, it may be possible to traverse the entire packet network using only the compressed speech (of the preferred codec). TrFO is basic function of codec Management.  Following are the benefits of achieving the TrFO:  1.) Improve the voice quality because of eliminati...