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Improvemnet Block FP decompression, common in case both U plane/C plane. 

1. Block FP is used in both U plane I.Q. samples and C plane beamforming
   weight decompression.
2. excluded digital power scaling(DPS) out of BFP decompression, i.e. (1<<15)
   bits shift, because DPS is applied only U plane.
3. added digital power scaling to be called from U plane I.Q. samples
   calculation.
4. improved U plane I.Q. samples calculation similar logic used in C
   plane bfw calculation.
5. improved U plane I.Q. samples index start from '0'.

reference: O-RAN WG4.CUS.0 v.09.00.
 8.1.2 and 8.1.3 for clarification, digital power scaling applied only U
   plane.
 annex A.1.2 and A.1.3 for clarification, digital power scaling not
included in Block FP.
 annex D for I.Q. smples index
This commit is contained in:
KATAOKA, Toshihiro 2022-07-20 04:39:01 +09:00 committed by Martin Mathieson
parent c41a27b96d
commit 6189eee63f
1 changed files with 23 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
epan/dissectors/packet-oran.c
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@ -550,6 +550,11 @@ static float uncompressed_to_float(guint32 h)
return ((float)i16) / 0x7fff;
}
static gfloat digital_power_scaling(gfloat f)
{
return f / (1 << 15);
}
static int dissect_bfwCompHdr(tvbuff_t *tvb, proto_tree *tree, gint offset,
guint32 *iq_width, guint32 *comp_meth, proto_item **comp_meth_ti)
{
@ -635,7 +640,7 @@ static gfloat decompress_value(guint32 bits, guint32 comp_method, guint8 iq_widt
}
const guint8 mantissa_bits = iq_width-1;
return (cPRB / (gfloat)(1 << (15+mantissa_bits))) * scaler;
return (cPRB / (gfloat)(1 << (mantissa_bits))) * scaler;
}
case COMP_BLOCK_SCALE:
@ -1020,7 +1025,7 @@ static int dissect_oran_c_section(tvbuff_t *tvb, proto_tree *tree, packet_info *
/* I value */
/* Get bits, and convert to float. */
guint32 bits = tvb_get_bits(tvb, bit_offset, iq_width, ENC_BIG_ENDIAN);
gfloat value = uncompressed_to_float(bits);
gfloat value = decompress_value(bits, COMP_BLOCK_FP, iq_width, exponent);
/* Add to tree. */
proto_tree_add_float_format_value(bfw_tree, hf_oran_bfw_i, tvb, bit_offset/8, (iq_width+7)/8, value, "%f", value);
bit_offset += iq_width;
@ -1032,7 +1037,7 @@ static int dissect_oran_c_section(tvbuff_t *tvb, proto_tree *tree, packet_info *
/* Q value */
/* Get bits, and convert to float. */
bits = tvb_get_bits(tvb, bit_offset, iq_width, ENC_BIG_ENDIAN);
value = uncompressed_to_float(bits);
value = decompress_value(bits, COMP_BLOCK_FP, iq_width, exponent);
/* Add to tree. */
proto_tree_add_float_format_value(bfw_tree, hf_oran_bfw_q, tvb, bit_offset/8, (iq_width+7)/8, value, "%f", value);
bit_offset += iq_width;
@ -1617,9 +1622,10 @@ dissect_oran_u(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _
for (guint i = 0; i < numPrbu; ++i) {
proto_item *prbHeading;
proto_tree *rb_tree = proto_tree_add_subtree(section_tree, tvb, offset, nBytesPerPrb, ett_oran_u_prb, &prbHeading, "PRB");
guint32 exponent = 0;
if (compression != COMP_NONE) {
proto_tree_add_item(rb_tree, hf_oran_rsvd4, tvb, offset, 1, ENC_NA);
proto_tree_add_item(rb_tree, hf_oran_exponent, tvb, offset, 1, ENC_NA);
proto_tree_add_item_ret_uint(rb_tree, hf_oran_exponent, tvb, offset, 1, ENC_BIG_ENDIAN, &exponent);
offset += 1;
}
@ -1631,20 +1637,24 @@ dissect_oran_u(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _
if (pref_showIQSampleValues) {
/* Individual values */
guint samples_offset = 0;
guint sample_number = 1;
while (samples_offset < nBytesForSamples*8) {
guint samples_offset = offset*8;
guint sample_number = 0;
for (guint n = 0; n<12; n++) {
/* I */
guint i_value = tvb_get_bits(tvb, samples_offset, sample_bit_width, ENC_BIG_ENDIAN);
guint i_bits = tvb_get_bits(tvb, samples_offset, sample_bit_width, ENC_BIG_ENDIAN);
gfloat i_value = decompress_value(i_bits, COMP_BLOCK_FP, sample_bit_width, exponent);
i_value = digital_power_scaling(i_value);
guint sample_len_in_bytes = ((samples_offset%8)+sample_bit_width+7)/8;
proto_item *i_ti = proto_tree_add_uint(rb_tree, hf_oran_iSample, tvb, offset+(samples_offset/8), sample_len_in_bytes, i_value);
proto_item_set_text(i_ti, "iSample: %5u 0x%04x (iSample-%u in the PRB)", i_value, i_value, sample_number);
proto_item *i_ti = proto_tree_add_uint(rb_tree, hf_oran_iSample, tvb, samples_offset/8, sample_len_in_bytes, i_value);
proto_item_set_text(i_ti, "iSample: %0.12f 0x%04x (iSample-%u in the PRB)", i_value, i_bits, sample_number);
samples_offset += sample_bit_width;
/* Q */
guint q_value = tvb_get_bits(tvb, samples_offset, sample_bit_width, ENC_BIG_ENDIAN);
guint q_bits = tvb_get_bits(tvb, samples_offset, sample_bit_width, ENC_BIG_ENDIAN);
gfloat q_value = decompress_value(q_bits, COMP_BLOCK_FP, sample_bit_width, exponent);
q_value = digital_power_scaling(q_value);
sample_len_in_bytes = ((samples_offset%8)+sample_bit_width+7)/8;
proto_item *q_ti = proto_tree_add_uint(rb_tree, hf_oran_qSample, tvb, offset+(samples_offset/8), sample_len_in_bytes, q_value);
proto_item_set_text(q_ti, "qSample: %5u 0x%04x (qSample-%u in the PRB)", q_value, q_value, sample_number);
proto_item *q_ti = proto_tree_add_uint(rb_tree, hf_oran_qSample, tvb, samples_offset/8, sample_len_in_bytes, q_value);
proto_item_set_text(q_ti, "qSample: %0.12f 0x%04x (qSample-%u in the PRB)", q_value, q_bits, sample_number);
samples_offset += sample_bit_width;
sample_number++;