4 RF Subsystem of the Macro NodeB

About This Chapter

The RF subsystem consists of the MAFUs and MTRUs and processes the RF signals.

4.1 Components of the Macro NodeB RF SubsystemThe RF subsystem consists of the MTRUs and MAFUs. The MTRU subrack contains theMTRUs and the MAFU subrack contains the MAFUs. A pair of MTRU and MAFU processesbi-carrier signals over one TX channel and two RX channels.

4.2 Functions of the Macro NodeB RF SubsystemThe boards of the RF subsystem form the RX channel and TX channel to process uplink RFsignals and downlink RF signals.

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4.1 Components of the Macro NodeB RF SubsystemThe RF subsystem consists of the MTRUs and MAFUs. The MTRU subrack contains theMTRUs and the MAFU subrack contains the MAFUs. A pair of MTRU and MAFU processesbi-carrier signals over one TX channel and two RX channels.

Figure 4-1 shows the components of the RF subsystem.

Figure 4-1 Components of the RF subsystem in full configuration

For details about the MTRU, refer to MTRU Module.

For details about the MAFU, refer to MAFU Module.

4.2 Functions of the Macro NodeB RF SubsystemThe boards of the RF subsystem form the RX channel and TX channel to process uplink RFsignals and downlink RF signals.

Figure 4-2 shows the functions of the RF subsystem.

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Figure 4-2 Logical structure of the RF subsystem

Operating Principles of TX Channel

The TX channel functions as follows:

1. The MTRU receives the downlink data distributed by the HBBI.

2. The MTRU converts the data into small RF signals at WCDMA transmit band throughpulse-shaping filtering, DUC, DAC, intermediate analog signal amplification, and up-conversion.

3. The HPA amplifies the small signals.

4. The MTRU sends the amplified signals to the MAFU.

5. The MAFU duplexer filters the signals, and then the MAFU sends the signals to the antennathrough the feeder.

6. The antenna transmits the signals.

Operating Principles of RX Channel

In two-way receive diversity mode, two ports of the antenna system receive UL signals fromUEs simultaneously. One port is used to receive and transmit signals; while the other is used toreceive signals only.

The RX channel functions as follows:

1. Antennas of the two-port antenna system receive weak signals from UEs and send them tothe MAFU through feeders.

2. In MAFUs, the duplexers filter the signals from the receiving-and-transmitting port andthe low noise amplifiers (LNAs) amplify the signals. Then the UL signals are sent to theMTRU.

3. In MAFUs, the filters process the signals from the receiving-only port and the LNAsamplify the signals. Then the UL signals are sent to the MTRU.

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4. The MTRU processes the signals and sends them to the HBBI after signal amplification,down-conversion, ADC, DDC, matched filtering, and DAGC.

NOTE

l If you configure a TMA, it can bypass the DL transmit signals to the antenna. Also, the TMA amplifiesthe UL signals and sends them to the MAFUs through the feeder.

l As shown in Figure 1, the common TX/RX port is named ANT A, and the RX port is named ANTB.

l For the single cabinet, two HBBIs are connected to all MTRUs and work in mutual backup mode.For the two combined cabinets, one HBBI is connected to the MTRUs in the primary cabinet, andthe other HBBI is connected to the MTRUs in the secondary cabinet. The two HBBIs workindependently.

l Two RX channels can be configured with RX diversity function.

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