In the previous article, we listed the IBE test requirement form. Today we will explain in detail how IBE is measured and calculated, and the IBE situation in CA/NR-DC/SUL/UL-MIMO/V2X/Tx Diversity mode.
01
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How IBE is Measured and Calculated
The IBE test is a measurement of the interference falling into the unassigned RB, which is the average transmission power of 12 subcarriers, calculated from the edge of the allocated uplink RB transmission bandwidth, under different RB offsets, in the unassigned RB The ratio of UE output power to UE output power in allocated RBs. The measurement interval is a slot in the time domain and averaged over 10 sub-frames. When the PUSCH or PUCCH transmission time slot becomes shorter due to multiplexing with the SRS, the in-band transmission measurement interval will be correspondingly reduced to one or more symbols.
For IBE measurement, the allocated RBs are required to be located at one end of the channel bandwidth and the other end is unallocated. Moreover, the number of allocated RBs is less than half of the total number of RBs, which means that RBs are not allocated near the center carrier.
In the test requirements table in the previous article, there are still many notes that we need to read carefully. First, for each RB evaluated, the minimum requirement is the higher of the values listed below:
PRB-30dB; Sum of power for all applicable limits (general, IQ image or carrier leakage);
Specifically, the following combinations:
Power (General) Power (General + IQ Image) Power (General + Carrier leakage)
As mentioned above, IBE is a ratio, but for testing three different power combinations, it is specifically divided into two different ratio calculation formulas:
Formula 1: Calculation of Power (General) and Power (General + IQ Image), which is the ratio (in dB) of the power of an unallocated measured RB to the average power of an allocated RB.
Formula 2: Calculation of Power (General + Carrier leakage), the ratio of the power of an unallocated RB to the power of all allocated RBs (in dBc).
This is why IBE has two relative emission (Emissions relative) calculation formulas. The specific process of calculation is as follows:
1. Calculate the absolute power of unallocated RBs:
: As learned in the previous article, it is the starting frequency offset between the allocated RB and the measured unallocated RB (for example,
=-1 or 1, indicating the first left and right adjacent RB outside the allocated RB bandwidth). So the upper and lower formulas are
The value of is greater than 0 or less than 0 to distinguish: the above formula indicates the IBE lower than the allocated frequency block, and the following formula indicates the IBE higher than the allocated frequency block;
Y(t,f): After the FFT of the demodulation link (refer to let’s learn the 5G terminal radio frequency standard (how to calculate EVM)), the unallocated RB samples in the transmission bandwidth configuration are called Y(t,f ) (f includes the unassigned subcarriers in the transmission bandwidth configuration, and t includes the OFDM symbol in 1 slot);
2. Calculate the power PRB and total power PAll-RBs of each RB allocated RB:
MS(t,f): the measurement data symbol samples of the allocated RB;
PAll-RBs is the sum of the power on all RBs (specifically subdivided into all subcarriers), and PRB is divided by the number of allocated RBs LCRB on the basis of PAll-RBs. Both are averaged in the Ts time domain;
3. Formula 1 for calculating the IBE of General and General + IQ Image: Consistent with the above definition, the ratio of the power of an unallocated measured RB to the average power of an allocated RB (subtracting the dB value).
4. Formula 2 for calculating the IBE of General + Carrier leakage: Consistent with the above definition, the ratio of the power of an unallocated measured RB to the average power of all allocated RBs (subtracting the dB value).
Here DCRB is one RB or a pair of RBs, depending on whether the DC is within one RB or between two RBs.
5. Average over n samples (10 UL subframes). The first is to average the linear power n times, and then perform the log dB conversion:
02
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IBE for CA/NR-DC/SUL/UL-MIMO/V2X/Tx Diversity
1. CA:
For UL inter-band CA allocated to two NR frequency bands, each active component carrier, UL PCC and SCC, needs to meet the requirements of single carrier IBE. The configuration is as follows: PCC with PRB allocation and SCC without PRB allocation, CSI report and SRS are not configured. And PCC and SCC should be switched test in each configuration.
2. NR-DC
The above-mentioned IBE of inter-band CA is suitable for NR-DC test, just replace PCC with PCell and replace SCC with PSCell.
3. SUL
The UE’s IBE requirements for a single carrier apply accordingly to the activated UL or SUL carrier. The configuration is as follows:
4. UL-MIMO
All NR power class 1.5, power class 2 and power class 3 UEs that support UL MIMO based on 2-layer codebook need to test IBE. For a UE with two transmit antenna connectors in a closed-loop spatial multiplexing scheme, the IBE requirements for a single carrier apply to each transmit antenna connector. Only the test steps of PUSCH are specified, and the test configuration is as follows:
5. V2X
Although the IBE of V2X has written a lot of content in the standard, the specific test configuration and steps are still in the state of TBD and FFS, so there is no way to test it yet. Let’s just understand what the IBE of V2X needs to measure. First of all, the IBE test specifies the following modes:
1) IBE for V2X / non-concurrent operation
2) IBE for V2X / non-concurrent operation / SL-MIMO
3) IBE for V2X / concurrent operation
For V2X sidelink physical channels PSCCH, PSSCH and PSBCH, the requirements of IBE should be the same as the corresponding modulation and transmission bandwidth specified by single carrier PUSCH. For the basic concepts of V2X channels and modes, you can refer to what we have learned before: let’s learn 5G terminal radio frequency standards (V2X transmit power -1).
6. Tx Diversity
For all types of NR power class 1.5 UEs that support Tx diversity, power class 2 and power class 3 UE R15 and later versions, the requirements for single carrier IBE apply to each Tx diversity transmit antenna connector.
The above information is compiled and released by Teslab. Welcome to discuss together. We have been paying attention to the development in this area. If there is any quotation, please indicate the source.
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