Service functions of the UMG8900

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The UMG8900 functions as a bearer device for voice and narrowband data services on the core network. It transmits service streams and converts formats of service streams between mobile networks and fixed networks, within mobile networks, and between mobile networks. For two networks that fully adopt the Internet Protocol (IP) transmission technology, service interworking between the IP networks can be implemented by means of domains.

The UMG8900 provides the service bearer processing function and the service stream format conversion function. By networking with the media gateway controller (MGC), the UMG8900 provides basic, supplementary, and intelligent network (IN) services.

Basic Services

Announcement playing and digit collecting, and dynamic loading of files: After loading the tone files that are adaptable towards syntax adaptation, the media gateway (MGW) can play intelligent tones about integers, numbers, time, durations, dates, and sums of money in different languages. The MGW can work with the network management system (NMS) to manage the tone files in a centralized manner.
Converting between codecs G.711A, G.711u, G.723.1, G.726, G.729, RFC 2833, adaptive multi-rate (AMR), AMR2, adaptive multi-rate wideband (AMR-WB)voice codecs, full rate (FR)/half rate (HR)/enhanced full rate (EFR) voice codecs in the global system for mobile communications (GSM) network.
Detection and generation of dual tone multi-frequency (DTMF) signals, RFC2198 redundancy, and RFC2833 detection.
Inter-working function (IWF) through an attached shared IWF (SIWF), including fax, synchronous data bearer, and asynchronous data bearer.

Supplementary Services

Using the teletype/text telephone devices for the deaf (TTY/TDD) to provide the mobile text voice service for the deaf.
Providing the global text telephony (GTT) function and providing mobile text voice services for the deaf.
Providing audio mixing and working with the MGC to support the multiparty service (MPTY).

Voice Enhancement Functions

Voice quality assurance technologies such as acoustic and electric echo cancellation (EC), voice activity detection (VAD), background noise suppression, comfort noise generation (CNG), automatic gain control (AGC), and packet loss concealment (PLC).
TFO/TrFO function

TrFO is a call configuration subject to the voice quality. In TrFO mode, the transcoder does not exist on the physical path. Therefore, no related conversion or control over transcoders exists, and the voice quality is improved. The TrFO function is defined in 3rd Generation Partnership Project (3GPP) R4 specifications.

Tandem free operation (TFO) is a connection configuration between two transcoders supporting the TFO protocol. When the codecs of the two transcoders are matched, this function enables in-band negotiation about codec selection instead of codec conversion, therefore improving voice quality. The TFO function is defined in 3GPP GSM, R99, and R4 specifications and supported by the UMG8900.

Enhanced System Functions

Various quality of service (QoS) assurance methods such as the setting of voice and data service priorities, dynamic jitter buffer (JB), IP type of service (ToS), differentiated service code point (DSCP), 802.1P/Q, and virtual local area network (VLAN) priority.
IP over E1 function, adapting IP data packets into TDM packets and implementing transparent transmission based on routes. Compressed Real-Time Protocol (CRTP) function and IP voice compressor plus (IVCP) function when the type of the IP bearer interface is Serial or VT: That is, the RTP packet is compressed, therefore reducing the bandwidth occupied by the RTP packet, and improving the transmission efficiency.
Interworking between VMGWs of one MGW

The conversion of transcoder channel (TC) codecs is not required, and therefore substantial TC resources are saved and the cost of network construction is reduced. The voice quality is also improved because voice transcoding occurs less frequently.
RTP multiplexing to reduce transmission bandwidth.
Working with the MGC to support the H.248.11 overload control protocol and the H.248.10 congestion control protocol, supporting the self overload protection function, and improving the completeness and stability of MGW protocols.
IP interworking within the MGW, looping back IP interfaces of IP terminations within the MGW without connecting routers or layer 3 switches but reducing the cost.

Embedded signaling gateway (SG) function

Adapting and forwarding signaling from the TDM bearer to the IP bearer based on Message Transfer Part layer 2 (MTP2) User Adaptation (M2UA)/Message Transfer Part layer 3 (MTP3) User Adaptation (M3UA)/Integrated Services Digital Network (ISDN) Q.921-User Adaptation layer (IUA) to simplify the network topology.
Adaptation of signaling system number 7 (SS7) common channel signaling (CCS), and adaptation and termination of channel associated signaling (CAS) such as R1, R2, R1.5, and International No.5 (No.5)/No.1 (No.1).