Their codec rates are as follows: AMR-NB AMR services are classified into AMR-NB services and AMR-WB services. For AMR services, the codec rates can be adjusted according to the change of radio environments to achieve better speech quality. In Table 3-2, the CS speech service defined by RAB Index 0 is known as Adaptive Multi-RateNarrowband (AMR-NB) service the CS speech service defined by RAB Index 1 is Adaptive MultiRate-Wideband (AMR-WB) service. Table 3-2 TRB specifications RAB Index CN Domain Table 3-2 lists the TRB specifications supported by Huawei RNC. The RAB ASSIGNMENT REQUEST message received from the CN contains information of traffic class, source statistics descriptor, and MBR. TRB Specifications The RNC automatically checks the identity of the CN domain that provides the services. This class does not have a high requirement for delay, but it requires data packets to be transmitted transparently at low bit error rates. Such services include email, SMS, and FTP. Its round trip time (RTT) is a key parameter, and data packets need to be transmitted transparently at low bit error rates.īackground class is used to receive or transmit data in background mode. Interactive class is used to carry traditional Internet services, such as Web browsing and database query. It does not have a high requirement for delay, but the time sequence must be kept within a data stream and the end-toend delay jitter of data streams must be controlled. Streaming class is used to carry unidirectional data streams. Therefore, this traffic class has the highest QoS requirement. The realtime traffic requires shortest delay and strict time sequence between data streams. The main difference between these classes is the degree of delay sensitivity, which is described as follows: TheĬonversational class is the most sensitive to delay. Traffic Class There are four traffic classes: conversational, streaming, interactive, and background. The traffic classes include conversational QoS, streaming QoS, interactive QoS and background QoS. This section describes the attributes of different traffic classes and the TRB specifications. Then, the RNC configures the associated parameters for each service based on RAB indexes. Table 3-1 SRB specifications SRB Indexģ.2 TRB Specifications The RNC searches for the RAB indexes of TRBs according to the attributes such as the core network (CN) domain, traffic class, source statistics descriptor, and maximum bit rate (MBR). Table 3-1 lists the SRB specifications supported by Huawei RNC. The RNC provides different sets of configuration parameters (including SRB maximum bit rate) for different typical services. 1 Radio Bearer Specifications Based on the type of transmitted data, the radio bearers are classified into two types: Signaling Trafficġ.1 SRB Specifications Different SRB specifications, that is, 3.4/6.8/13.6/27.2 kbit/s RRC Connection and RAB Assignment is supported to meet the QoS requirements for different services.