Signalling for seamless interaction between networks and devices ITU-T SG16, Q18/16 Names

1. Signalling for seamlessinteraction between networks and devicesITU-T SG16,Q18/16Names

2. Modern telephony networks rely on a set of voice-quality enhancement (VQE) features for optimum quality of experience • For maximum effectiveness of VQE features it is necessary: • - To deploy all applicable VQE features • - To avoid multiple (tandem) application of the same feature • - To exercise the feature at the optimal location along the call path • The intent of draft ITU-T G.MDCSPNE is to develop the generic framework for the dynamic coordination of VQEs present on bearer paths for the purpose of improving overall end-to-end voice quality Motivation

3. SC-T Server MSC-T Server MSC-O MGW-O MGW-T SPNE-T BSC-O Circuit-Switchednetwork IP packet network Land User Mobile Phone G.MDCSPNE Q.115.x Scope and Applicability of G.MDCSPNE Media Path Signalling Path

4. Feedback • Automatic Level • Control • Network Echo • Canceller • Automatic • Level Control • Acoustic • Echo Control • Acoustic Echo • Control - Automatic Level Control Acoustic Echo Hybrid Echo Challenges in Mobility Communications • Dynamic VQE insertion/removal due to dynamic call configuration and modification • Permutation of points of VQE feature deployment • Variety of topologies : inter-MSC, intra-MSC • Example of Use Cases: • Mobile-land calls • Mobile-mobile calls • Mobile calls with handover • Mobile calls with call transfer • Landline calls transferred to mobile

5. Dynamic Coordination Mechanism • Dynamic coordination of VQE is achieved through: • An encapsulation format (capability list) to facilitate identification of VQE capabilities from different equipment/devices in a dynamic manner • Rules for exchange of capability lists among nodes in a call-path, for VQE coordination in static and dynamic call configurations • VQE engagement rules executed by individual equipment/devices based on common view of capabilities available along a given bearer path

6. Capability List Format 7 6 5 4 3 2 1 0 Descriptions V F N Common Part SPID Length Reserved ID Entry 1 Reserved Len Attribute Reserved ID Entry 2 Reserved Len Attribute ¼ ¼ Common part: V (3 bits): Version number F (1 bit): Forward / Reverse flag N (4 b its): Number of entries SPID (16 bits): SPNE /device Identifier Length (8 bits): Capability - list size in bytes (common + entries) Entry part: ID (4 bits): VQE entry identifier Len (4 bits): Entry size in bytes, including the entry ID byte and the entry L en byte and the attribute bytes Attribute: Entry attribute information with zero, one or multiple bytes (To be defined) Reserved: Reserved field with a value of 0x00

7. Each entry(cell) corresponds to a specific Speech Processing Function • Speech Processing Function includes, but is not limited to: • Network Echo Cancellation (EC), • Acoustic Echo Control (AEC), • Automatic Level Control (ALC), • Noise Reduction (NR), • Feedback Automatic Level • Control (FBALC) • Capability List received is updated with new information and sent to next SPNE, if necessary • Each SPNE enables or disables its function based on Capability view, in accordance with pre-determined coordination rules Forward Capability List Received Forward Capability List Update Capability List Exchange SPNE Speech Processing Functions/Devices Signal Flow Reverse Capability List Update Reverse Capability List Received

8. VQE Engagement Rules • AEC : as close as possible to the source of acoustic echo • ALC : as close as possible to the signal source • EC : as close as possible to the local loop • FBALC : as close as possible to the destination • NR : as close as possible to the signal source Engagement example in mobile-land call (for bearer traffic from left to right) SPNE-1 SPNE-2 SPNE-3 Acoustic echo

9. Coordination Examples

10. VoIP Mobile-Mobile Call With Handover Call flow: Mobile-mobile call between MS-1 and MS-2 via media gateways MG-1 and MG-2 MS-2 experiences a handover Mobile-mobile call between MS-1 and MS-2 via media gateways MG-1 and MG-3 MG2 FBALC AEC Dec FBALC Enc IP Enc FBALC Dec AEC ALC MS2 AEC Dec MS1 MG1 Enc AEC Enc: Low bit rate encoder Dec: Low bit rate decoder FBALC: Feedback Automatic Level Control ALC: Automatic Level Control AEC: Acoustic Echo Control MG3

11. VQE Coordination : Before Handover MG-1 realizes that it is the first and last SPNE supporting AEC on MS-1MS-2 traffic realizes that it is the first SPNE supporting ALC but there is a FBALC downstream on MS-1MS-2 traffic MG-2 realizes that there is an ALC upstream but it is the last one with FBALC on MS-1MS-2 traffic Coordination Outcome According to the preference rule, MG-2 continues FBALC support on MS-1MS-2 traffic, and MG-1 disables ALC on MS-1MS-2 traffic For Traffic flow from MS1 to MS2 MG2 FBALC AEC Dec FBALC Enc IP Enc FBALC Dec AEC ALC MS2 AEC Dec MS1 MG1 Enc AEC Enc: Low bit rate encoder Dec: Low bit rate decoder FBALC: Feedback Automatic Level Control ALC: Automatic Level Control AEC: Acoustic Echo Control MG3

12. VQE Coordination : After Handover For Traffic flow from MS1 to MS2 • MG-1 • realizes that it is the first and last one with ALC, and it is the first but not the last with AEC on MS-1MS-2 traffic, • MG-3 • realizes that there is an AEC upstream closer to the source on MS-1MS-2 traffic • Coordination Outcome • MG-1 continues AEC support on MS-1MS-2 traffic. • MG-1 dynamically re-enables ALC support on MS-1MS-2 traffic. • MG-3 disables its AEC. MG2 FBALC AEC Dec FBALC Enc IP Enc FBALC Dec AEC ALC MS2 AEC Dec MS1 MG1 Enc AEC Enc: Low bit rate encoder Dec: Low bit rate decoder FBALC: Feedback Automatic Level Control ALC: Automatic Level Control AEC: Acoustic Echo Control MG3

13. Generic Network Configuration SC-T Server MSC-T Server MSC-O MGW-O MGW-T SPNE-T BSC-O Circuit-Switchednetwork IP packet network Land User Mobile Phone G.MDCSPNE Q.115.x Media Path Signalling Path

14. Coordination Voice enhancement processing functions MS-O MGW-O MGW-T SPNE-T Tandeming (results) Acoustic Echo Control (AEC) Yes Yes Enabled Yes Yes Disabled No No No No No No Yes Yes No Q G Noise reduction (NR-O) for media from the mobile user Yes Yes Enabled Yes Yes Disabled Yes Yes Disabled Yes Disabled Disabled Yes Yes No Echo Cancellation (EC) for Sin from the land user No No No No No No Yes Disabled Disabled Yes Enabled Enabled Yes No No Noise reduction (NR-T) for media from the land user No No No Yes Yes Disabled Yes Disabled Disabled Yes Enabled Enabled Yes Yes No Q.115.x（Call set-up) (Dynamic coordination) G.MDCSPNE

15. Dynamic Coordination of SPNE (G.MDCSPNE) – current status & future plans • Q18/16 has almost reached consensus on coordination mechanism and proceeded to discuss detailed designs, • Study on the protocols to exchange Capability Lists are necessary, • SG16 is asking SG11 and other SDOs for the guidance on the available protocols, especially for wireless links, • SG11 and other SDOs are invited to liaise with SG16 on these aspects, • The separation of frame work part and implementation-dependent parts have been agreed, • The target date for AAP consent on core part is expected to be at the SG16 meeting to be held in October 2009.