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FAQ for TD-LTE Applications on Signal Sources and Signal Analyzers

  • Which release of the 3GPP technical specifications do Agilent solutions now?
    The Agilent signal generators ESG and MXG with Signal Studio for 3GPP LTE TDD (model number: N7525B) and X-Series signal analyzers with 89600 Vector Signal Analysis software (89601A-BHE) or LTE TDD measurement application (N9082A) all support the March 2009 (2009-03) LTE standard. Supported version list here:
LTE TDD spec version (36.211)Signal Studio version N7625B (MXG/ESG/PXB)VSA version LTE TDD modulation analysis 89601A-BHELTE TDD meas application N9082A (MXA/EXA)
March 2009 (v8.6.0)2.0.1.0Vsa_11.00.395A.03.06
  • Does the Agilent solution support the 4x4 MIMO tests for LTE TDD?
    Yes, the N7625B can make downlink MIMO configurations (up to 4x4) with static fading including spatial multiplexing with CDD (cyclic delay diversity) and transmit diversity. The 89601A-BHE can support the 4x4 MIMO analysis using Agilent Oscilloscopes.
  • Does the ESG or MXG with N7625B Signal Studio support the UE receiver tests?
    Yes, the E4438C or N5182A with the N7625B Signal Studio for 3GPP LTE TDD can generate both LTE TDD downlink and uplink signals. So It can be used for receiver components (such as power amplifiers and transmitter, receiver, or transceiver RFICs) and UE receiver tests. But since many of the UE receiver tests in the 3GPP standards are not yet completely defined, we will keep the solution updated following on the standards changes.
  • Can the 89601A-BHE or N9082A be used for multi-user modulation analysis on PUSCH and PUCCH?
    Yes, the 89601A-BHE and N9082A can detect the multi-user signals at one time, but for the EVM tests, they both only provide single user modulation analysis results at one-by-one.
  • Does the N7625B support multi-user PRACH generation?
    Yes. Agilent’s products support multi-user PRACH generation.
    In the N7625B, besides “Basic LTE TDD” and “Advanced LTE TDD carriers”, there is another carrier type named “PRACH LTE TDD”. You can setup either single user PRACH or multi-user PRACH with this carrier type. The preamble is allocated in uplink subframes and UpPTS. The exact preamble position depends on the Uplink/Downlink Configuration, PRACH Configuration Index and Frequency Offset.
  • Does the signal analyzer support multi-user PRACH demodulation?
    Yes, both MXA N9082A and 89601A software can analyze multi-user PRACH. Manually add PRACH users under Edit User Mapping. You can monitor one user’s constellation at the same time. You can also detect multi-user with the Detected Allocations trace.
  • Can we test TD-LTE CCDF in 89601A-BHE?
    Yes, you can test CCDF with both N9082A and 89601A-BHE.
    Because the TD-LTE signal is a bursted signal, the CCDF testing should cooperate with the time gate which only captures the signal you want. In the N9082A, a gate function is coupled with the CCDF measurement. You can view the gate window under CCDF measurement by turning on [View/Display] -> {slot view} ->on.
    In the 89601A-BHE, the “measurement interval” parameter controls the time gate effect on the signal and can be treated as the gate length. The “measurement offset” parameter can be treated as a gate delay. After setting the correct parameters to measure the burst-on part, you will get the correct CCDF result.
  • Does the N7625B and the N9082A support the LTE TDD E-TM with 2-frames?
    Yes. The both the N7625B and the N9082A fully support the 2-frame (40 slots) requirement in the 3GPP standards for LTE TDD E-TMs.
  • How does the the MXA/EXA with N9082A do the PvT measurement?
    In the 3GPP standard document (TS36.141), the PvT is named Transmit On/Off power, which consists of Transmitter Off power and Transmitter transient period. This test item is only applied for the TDD eNB. Agilent makes a significant and excellent solution of the On/Off power measurement using a dual sweep, each with different pre-amplifier and attenuation setups.
    In the real word, since the maximum output power of the eNB is normally around +43dBm, an external attenuator inserted between the BS and analyzer is required. This external attenuator should increase the noise level of the analyzer, please contact Agilent sales and support directly for the measurement details.
  • For MIMO testing with two MXAs or two EXAs, does the 89601A VSA software need option BHE for both MXA’s?
    No, in this case, the 89601A option BHE is only need for the VSA that is acting as the controlling PC. If VSA is run inside of the MXAs, that one needs a BHE option. If VSA is running on an external PC, that PC’s VSA needs the BHE option.
  • What kind of baseband filter is used for P-SS?
    The LTE standard does not specify what transmitter filter to use. For the transmitter in ADS, we use ideal low pass filter or RRC filter; for signal studio, we use ideal low pass filter to filter baseband signal, no specific filtering on P-SS. In the LTE TDD measurement application, we do not use any additional receiving filter except that MXA filters the input signal according to span for different bandwidth.
  • In ACLR eNB limit, LTE 3MHz bandwidth adjacent channel carrier filter BW is the same as channel BW. Is this true?
    No. The bandwidth of filter should be transmission bandwidth configuration BWconfig, not channel BW.