data

int16_t* nrf_modem_rs_capture_prs_sample::data

Data samples.

Number of data samples is indicated in num_samples variable.

Frequency domain samples, 16bit signed I & Q, I first.

8 PRB's (96 subcarriers) are stored per OFDM symbol, in frequency increasing order (subcarrier #0 first, #95 last).

Only OFDM symbols containing PRS are stored except in 4 TX antenna configuration, where every eight symbols is invalid.

If present based on num_samples variable, number of samples are 2 (I+Q) * 8 PRS symbols * 8 PRBs * 12 subcarriers = 1536 samples.

Centermost 6 PRB's (#1..#6, from #0..#7) within these 8 PRB's always correspond to the configured LTE-M narrowband (nb variable).

If either or both PRB's on the edge (PRB #0 and/or #7) are outside of the LTE cell bandwidth, they are still returned but do not contain LTE signal. This happens if cell bandwidth is 1.4MHz, or cell bandwidth is 5MHz and first or last narrowband is configured.

When LTE-M narrowband reception is configured (nb variable is 1..16):

• UE RF center frequency is set at the first subcarrier of PRB #4 (subcarrier #48), except when physical cell ID mod 3 == 0, when it is at the second subcarrier of PRB #4 (subcarrier #49).
• This subcarrier is zeroed in the data.
• Phase offset caused by subcarrier offset between UE RF center frequency and cell center frequency is compensated in the data.
• If empty subcarrier at the cell center is within the 8 PRB reception window, it is removed from the data.

When LTE cell center frequency reception is configured (nb variable is zero):

• UE RF center frequency is set at the empty subcarrier at cell center. This subcarrier is removed from the data.