6.5 Transmitted signal quality

36.1043GPPBase Station (BS) radio transmission and receptionEvolved Universal Terrestrial Radio Access (E-UTRA)Release 18TS

The requirements in clause 6.5 apply to the transmitter ON period.

6.5.1 Frequency error

Frequency error is the measure of the difference between the actual BS transmit frequency and the assigned frequency. The same source shall be used for RF frequency and data clock generation.

6.5.1.1 Minimum requirement

For E-UTRA, the modulated carrier frequency of each E-UTRA carrier configured by the BS shall be accurate to within the accuracy range given in Table 6.5.1-1 observed over a period of one subframe (1ms).

For NB-IoT, the modulated carrier frequency of each NB-IoT carrier configured by the BS shall be accurate to within the accuracy range given in Table 6.5.1-1 observed over a period of one subframe (1ms).

Table 6.5.1-1: Frequency error minimum requirement

BS class	Accuracy
Wide Area BS	±0.05 ppm
Medium Range BS	±0.1 ppm
Local Area BS	±0.1 ppm
Home BS	±0.25 ppm

6.5.2 Error Vector Magnitude

The Error Vector Magnitude is a measure of the difference between the ideal symbols and the measured symbols after the equalization. This difference is called the error vector. The equaliser parameters are estimated as defined in Annex E. The EVM result is defined as the square root of the ratio of the mean error vector power to the mean reference power expressed in percent.

For E-UTRA, for all bandwidths, the EVM measurement shall be performed for each E-UTRA carrier over all allocated resource blocks and downlink subframes within 10ms measurement periods for subframe TTI, and over all allocated resource blocks and downlink sTTIs within 10ms measurement periods for sTTI. The boundaries of the EVM measurement periods need not be aligned with radio frame boundaries. The EVM value is then calculated as the mean square root of the measured values. The EVM of each E-UTRA carrier for different modulation schemes on PDSCH or sPDSCH shall be better than the limits in table 6.5.2-1:

Table 6.5.2-1: EVM requirements for E-UTRA carrier

Modulation scheme for PDSCH or sPDSCH	Required EVM [%]
QPSK	17.5 %
16QAM	12.5 %
64QAM	8 %
256QAM	3.5 %
1024QAM	2.5 %

For NB-IoT, for all bandwidths, the EVM measurement shall be performed for each NB-IoT carrier over all allocated resource and downlink subframes within 10ms measurement periods. The boundaries of the EVM measurement periods need not be aligned with radio frame boundaries. The EVM value is then calculated as the mean square root of the measured values. The EVM of each NB-IoT carrier on NB-PDSCH shall be better than the limits in Table 6.5.2-2:

Table 6.5.2-2: EVM requirements for NB-IoT carrier

Modulation scheme for NB-PDSCH	Required EVM [%]
QPSK	17.5 %
16QAM	12.5%

6.5.3 Time alignment error

This requirement applies to frame timing in TX diversity, MIMO transmission, carrier aggregation and their combinations.

Frames of the LTE signals present at the BS transmitter antenna port(s) are not perfectly aligned in time. In relation to each other, the RF signals present at the BS transmitter antenna port(s) experience certain timing differences.

For a specific set of signals/transmitter configuration/transmission mode, time alignment error (TAE) is defined as the largest timing difference between any two signals.

6.5.3.1 Minimum Requirement

For E-UTRA:

– For MIMO or TX diversity transmissions, at each carrier frequency, TAE shall not exceed 65 ns.

– For intra-band contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 130 ns.

– For intra-band non-contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 260 ns.

– For inter-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 260ns.

For NB-IoT:

– For TX diversity transmissions, at each carrier frequency, TAE shall not exceed 65 ns.

6.5.4 DL RS power

For E-UTRA, DL RS power is the resource element power of the Downlink Reference Symbol.

The absolute DL RS power is indicated on the DL-SCH. The absolute accuracy is defined as the maximum deviation between the DL RS power indicated on the DL-SCH and the DL RS power of each E-UTRA carrier at the BS antenna connector.

For NB-IoT, DL NRS power is the resource element power of the Downlink Narrow-band Reference Signal.

The absolute DL NRS power is indicated on the DL-SCH. The absolute accuracy is defined as the maximum deviation between the DL NRS power indicated on the DL-SCH and the DL NRS power of each NB-IoT carrier at the BS antenna connector.

6.5.4.1 Minimum requirements

For E-UTRA, DL RS power of each E-UTRA carrier shall be within ± 2.1 dB of the DL RS power indicated on the DL-SCH.

For NB-IoT, DL NRS power of each NB-IoT carrier shall be within ± 2.1 dB of the DL NRS power indicated on the DL-SCH.