CPRI LTE RF Analyzer and BBU Emulator : CPRI LTE RF Analyzer : CPRI Configuration
CPRI Configuration
The primary application for CPRI LTE RF is to check for interference on the RRH-to-BBU uplink. The easiest way to configure the Anritsu instrument for CPRI testing is to select one of the radio presets provided with the CPRI application, then use the Auto Detect feature to automatically determine and apply the appropriate configuration settings.
If no radio preset is available for the RRH being tested or you don’t know who the equipment manufacturer is, you can still use the Auto Detect feature by entering custom settings for the IQ bit width, number of reserve bits, and aggregation condition. Set these parameters via the Custom Settings Menu or the Auto-Detect dialog illustrated in Figure: CPRI Parameter Auto-Detect Dialog.
Other parameters required in configuring the CPRI link are the line rate, the LTE carrier bandwidth, and the AxC group number. Refer to CPRI Parameters and CPRI Config Menu.
Radio Presets
Radio presets are currently available for the uplink and downlink signals associated with specific equipment manufacturers like Nokia/ALu (Alcatel-Lucent), Ericsson, Huawei, or Samsung.
Uplink – RRH to BBU
Downlink – BBU to RRH
To choose a radio preset:
1. Press the Measurements key in CPRI Mode.
2. Press CPRI Configure, then select SFP Port1 Config or SFP Port2 Config, as appropriate (dual-port models only).
3. Press Radio Presets.
4. Press the appropriate key or keys for the RRH vendor and uplink or downlink. Refer to Radio Presets Menu.
Selecting No Preset will maintain the current settings for IQ Bit Width, Reserve Bit and Mapping Method, and Aggregation is set to Off.
5. If the selected preset is Ericsson UL or Ericsson DL, choose between CPRI Aggregation Off or On and set the Reserve Containers as needed. See Figure: Ericsson Radio Preset Menu.
You can also select a radio preset by pressing Auto Detect instead of Radio Presets in Step 3. On the CPRI Param Auto-Detect screen, press Radio Preset, then choose the desired preset from the drop-down list.
To manually set the IQ bit width, number of reserve bits, and aggregation condition instead of applying a radio preset, select Custom Settings from the Radio Preset drop-down list, then enter each parameter as appropriate. These parameters are also accessible under the Radio Presets Custom Settings menu for the SFP port being configured.
CPRI Parameter Automatic Detection
Use the Auto Detect feature when you have limited information on the CPRI link to be tested. The test instrument will search for potentially matching signals based on the selected radio preset or the custom settings for IQ bit width, number of reserve bits, and CPRI aggregation on or off.
To start the CPRI automatic detection, select the radio preset or custom settings as described in Radio Presets, then press the Start Auto Detect key under the SFP Port1 (or Port2) Auto Detect menu.
The CPRI Analyzer will determine the line rate automatically and highlight in color any available AxC group in the specific carrier bandwidth. See Figure: CPRI Parameter Auto‑Detect Screen. More than one button may be highlighted. The results of Auto Detect provide a smaller number of potentially matching signals out of the possible results for a specific line rate. You must check each highlighted button until you find the desired signal.
When you press a highlighted button in the results area, the Auto Detect screen closes, and the signal trace is displayed.
CPRI Parameter Auto‑Detect Screen
Radio Preset drop‑down list (vendor preset or custom settings)
IQ Bit Width (10, 12, 15, or 16)
Reserve Bits (0 to 10)
CPRI Aggregation (Off/On)
Line Rate setting (1 through 8)
Antenna Container Groups
LTE Carrier Bandwidth (5 MHz, 10 MHz, 15 MHz, 20 MHz)