From 25398ec0893a22eef5e6b64f4f7f8aae716b3710 Mon Sep 17 00:00:00 2001 From: Ismael Gomez Date: Thu, 20 Oct 2016 11:27:15 +0200 Subject: [PATCH] Added comment to clarify cross-correlation in PSS --- srslte/lib/sync/pss.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/srslte/lib/sync/pss.c b/srslte/lib/sync/pss.c index f7edbb353..46c02414e 100644 --- a/srslte/lib/sync/pss.c +++ b/srslte/lib/sync/pss.c @@ -304,7 +304,12 @@ int srslte_pss_synch_find_pss(srslte_pss_synch_t *q, cf_t *input, float *corr_pe return SRSLTE_ERROR; } - /* Correlate input with PSS sequence */ + /* Correlate input with PSS sequence + * + * We do not reverse time-domain PSS signal because it's conjugate is symmetric. + * The conjugate operation on pss_signal_time has been done in srslte_pss_synch_init_N_id_2 + * This is why we can use FFT-based convolution + */ if (q->frame_size >= q->fft_size) { #ifdef CONVOLUTION_FFT memcpy(q->tmp_input, input, q->frame_size * sizeof(cf_t));