563 lines
13 KiB
C++
563 lines
13 KiB
C++
/*
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* Copyright (C) 2013 by Holger Hans Peter Freyther
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "bts.h"
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#include "gprs_debug.h"
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#include <gprs_coding_scheme.h>
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#include <rlc.h>
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#include <stdbool.h>
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#include <string.h>
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#include <sys/types.h>
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extern "C" {
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#include <osmocom/core/utils.h>
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#include <osmocom/core/bitvec.h>
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#include <osmocom/core/logging.h>
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}
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uint8_t *gprs_rlc_data::prepare(size_t block_data_len)
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{
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/* todo.. only set it once if it turns out to be a bottleneck */
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memset(block, 0x0, sizeof(block));
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memset(block, 0x2b, block_data_len);
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/* Initial value of puncturing scheme */
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next_ps = EGPRS_PS_1;
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return block;
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}
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void gprs_rlc_data::put_data(const uint8_t *data, size_t data_len)
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{
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memcpy(block, data, data_len);
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len = data_len;
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}
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void gprs_rlc_v_b::reset()
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{
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for (size_t i = 0; i < ARRAY_SIZE(m_v_b); ++i)
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mark_invalid(i);
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}
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void gprs_rlc_dl_window::reset()
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{
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m_v_s = 0;
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m_v_a = 0;
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m_v_b.reset();
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}
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int gprs_rlc_dl_window::resend_needed() const
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{
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for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) {
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if (m_v_b.is_nacked(bsn) || m_v_b.is_resend(bsn))
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return bsn;
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}
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return -1;
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}
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int gprs_rlc_dl_window::mark_for_resend()
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{
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int resend = 0;
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for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) {
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if (m_v_b.is_unacked(bsn)) {
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/* mark to be re-send */
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m_v_b.mark_resend(bsn);
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resend += 1;
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}
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}
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return resend;
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}
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/* Update the receive block bitmap */
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uint16_t gprs_rlc_ul_window::update_egprs_rbb(uint8_t *rbb)
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{
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uint16_t i;
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uint16_t bsn;
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uint16_t bitmask = 0x80;
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int8_t pos = 0;
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int8_t bit_pos = 0;
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for (i = 0, bsn = (v_q()+1); ((bsn < (v_r())) && (i < ws())); i++,
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bsn = this->mod_sns(bsn + 1)) {
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if (m_v_n.is_received(bsn)) {
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rbb[pos] = rbb[pos] | bitmask;
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} else {
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rbb[pos] = rbb[pos] & (~bitmask);
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}
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bitmask = bitmask >> 1;
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bit_pos++;
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bit_pos = bit_pos % 8;
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if (bit_pos == 0) {
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pos++;
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bitmask = 0x80;
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}
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}
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return i;
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}
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int gprs_rlc_dl_window::count_unacked()
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{
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uint16_t unacked = 0;
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uint16_t bsn;
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for (bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) {
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if (!m_v_b.is_acked(bsn))
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unacked += 1;
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}
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return unacked;
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}
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static uint16_t bitnum_to_bsn(int bitnum, uint16_t ssn)
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{
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return (ssn - 1 - bitnum);
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}
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void gprs_rlc_dl_window::update(BTS *bts, const struct bitvec *rbb,
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uint16_t first_bsn, uint16_t *lost,
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uint16_t *received)
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{
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unsigned dist = distance();
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unsigned num_blocks = rbb->cur_bit > dist
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? dist : rbb->cur_bit;
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unsigned bsn;
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/* first_bsn is in range V(A)..V(S) */
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for (unsigned int bitpos = 0; bitpos < num_blocks; bitpos++) {
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bool is_ack;
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bsn = mod_sns(first_bsn + bitpos);
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if (bsn == mod_sns(v_a() - 1))
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break;
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is_ack = bitvec_get_bit_pos(rbb, bitpos) == 1;
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if (is_ack) {
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LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn);
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if (!m_v_b.is_acked(bsn))
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*received += 1;
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m_v_b.mark_acked(bsn);
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} else {
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LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn);
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m_v_b.mark_nacked(bsn);
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bts->rlc_nacked();
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*lost += 1;
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}
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}
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}
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void gprs_rlc_dl_window::update(BTS *bts, char *show_rbb, uint16_t ssn,
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uint16_t *lost, uint16_t *received)
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{
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/* SSN - 1 is in range V(A)..V(S)-1 */
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for (int bitpos = 0; bitpos < ws(); bitpos++) {
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uint16_t bsn = mod_sns(bitnum_to_bsn(bitpos, ssn));
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if (bsn == mod_sns(v_a() - 1))
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break;
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if (show_rbb[ws() - 1 - bitpos] == 'R') {
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LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn);
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if (!m_v_b.is_acked(bsn))
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*received += 1;
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m_v_b.mark_acked(bsn);
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} else {
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LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn);
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m_v_b.mark_nacked(bsn);
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bts->rlc_nacked();
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*lost += 1;
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}
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}
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}
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int gprs_rlc_dl_window::move_window()
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{
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int i;
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uint16_t bsn;
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int moved = 0;
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for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) {
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if (m_v_b.is_acked(bsn)) {
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m_v_b.mark_invalid(bsn);
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moved += 1;
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} else
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break;
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}
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return moved;
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}
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void gprs_rlc_dl_window::show_state(char *show_v_b)
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{
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int i;
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uint16_t bsn;
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for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) {
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uint16_t index = bsn & mod_sns_half();
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switch(m_v_b.get_state(index)) {
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case GPRS_RLC_DL_BSN_INVALID:
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show_v_b[i] = 'I';
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break;
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case GPRS_RLC_DL_BSN_ACKED:
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show_v_b[i] = 'A';
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break;
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case GPRS_RLC_DL_BSN_RESEND:
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show_v_b[i] = 'X';
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break;
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case GPRS_RLC_DL_BSN_NACKED:
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show_v_b[i] = 'N';
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break;
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default:
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show_v_b[i] = '?';
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}
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}
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show_v_b[i] = '\0';
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}
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void gprs_rlc_v_n::reset()
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{
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for (size_t i = 0; i < ARRAY_SIZE(m_v_n); ++i)
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m_v_n[i] = GPRS_RLC_UL_BSN_INVALID;
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}
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void gprs_rlc_window::set_sns(uint16_t sns)
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{
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OSMO_ASSERT(sns >= RLC_GPRS_SNS);
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OSMO_ASSERT(sns <= RLC_MAX_SNS);
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/* check for 2^n */
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OSMO_ASSERT((sns & (-sns)) == sns);
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m_sns = sns;
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}
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void gprs_rlc_window::set_ws(uint16_t ws)
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{
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LOGP(DRLCMAC, LOGL_INFO, "ws(%d)\n",
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ws);
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OSMO_ASSERT(ws >= RLC_GPRS_SNS/2);
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OSMO_ASSERT(ws <= RLC_MAX_SNS/2);
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m_ws = ws;
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}
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/* Update the receive block bitmap */
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void gprs_rlc_ul_window::update_rbb(char *rbb)
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{
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int i;
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for (i=0; i < ws(); i++) {
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if (m_v_n.is_received((ssn()-1-i) & mod_sns()))
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rbb[ws()-1-i] = 'R';
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else
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rbb[ws()-1-i] = 'I';
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}
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}
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/* Raise V(R) to highest received sequence number not received. */
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void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn)
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{
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uint16_t offset_v_r;
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offset_v_r = mod_sns(bsn + 1 - v_r());
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/* Positive offset, so raise. */
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if (offset_v_r < (sns() >> 1)) {
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while (offset_v_r--) {
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if (offset_v_r) /* all except the received block */
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m_v_n.mark_missing(v_r());
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raise_v_r_to(1);
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}
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n", v_r());
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}
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}
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/*
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* Raise V(Q) if possible. This is looped until there is a gap
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* (non received block) or the window is empty.
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*/
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uint16_t gprs_rlc_ul_window::raise_v_q()
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{
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uint16_t count = 0;
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while (v_q() != v_r()) {
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if (!m_v_n.is_received(v_q()))
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break;
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LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising "
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"V(Q) to %d\n", v_q(), mod_sns(v_q() + 1));
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raise_v_q(1);
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count += 1;
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}
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return count;
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}
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void gprs_rlc_ul_window::receive_bsn(const uint16_t bsn)
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{
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m_v_n.mark_received(bsn);
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raise_v_r(bsn);
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}
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bool gprs_rlc_ul_window::invalidate_bsn(const uint16_t bsn)
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{
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bool was_valid = m_v_n.is_received(bsn);
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m_v_n.mark_missing(bsn);
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return was_valid;
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}
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static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc,
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GprsCodingScheme cs, bool with_padding, unsigned int header_bits,
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const unsigned int spb)
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{
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unsigned int i;
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unsigned int padding_bits = with_padding ? cs.optionalPaddingBits() : 0;
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rlc->cs = cs;
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rlc->r = 0;
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rlc->si = 0;
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rlc->tfi = 0;
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rlc->cps = 0;
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rlc->rsb = 0;
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rlc->usf = 0;
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rlc->es_p = 0;
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rlc->rrbp = 0;
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rlc->pr = 0;
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rlc->num_data_blocks = num_data_blocks(cs.headerTypeData());
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rlc->with_padding = with_padding;
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OSMO_ASSERT(rlc->num_data_blocks <= ARRAY_SIZE(rlc->block_info));
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for (i = 0; i < rlc->num_data_blocks; i++) {
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gprs_rlc_data_block_info_init(&rlc->block_info[i], cs,
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with_padding, spb);
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rlc->data_offs_bits[i] =
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header_bits + padding_bits +
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(i+1) * num_data_block_header_bits(cs.headerTypeData()) +
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i * 8 * rlc->block_info[0].data_len;
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}
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}
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void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
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GprsCodingScheme cs, bool with_padding, const unsigned int spb)
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{
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return gprs_rlc_data_header_init(rlc, cs, with_padding,
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num_data_header_bits_DL(cs.headerTypeData()), spb);
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}
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void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
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GprsCodingScheme cs, bool with_padding)
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{
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/*
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* last parameter is sent as 0 since common function used
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* for both DL and UL
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*/
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return gprs_rlc_data_header_init(rlc, cs, with_padding,
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num_data_header_bits_UL(cs.headerTypeData()), 0);
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}
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void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
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GprsCodingScheme cs, bool with_padding, const unsigned int spb)
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{
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unsigned int data_len = cs.maxDataBlockBytes();
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if (with_padding)
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data_len -= cs.optionalPaddingBits() / 8;
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rdbi->data_len = data_len;
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rdbi->bsn = 0;
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rdbi->ti = 0;
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rdbi->e = 1;
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rdbi->cv = 15;
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rdbi->pi = 0;
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rdbi->spb = spb;
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}
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unsigned int gprs_rlc_mcs_cps(GprsCodingScheme cs,
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enum egprs_puncturing_values punct,
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enum egprs_puncturing_values punct2, bool with_padding)
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{
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/* validate that punct and punct2 are as expected */
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switch (CodingScheme(cs)) {
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case MCS9:
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case MCS8:
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case MCS7:
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if (punct2 == EGPRS_PS_INVALID) {
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LOGP(DRLCMACDL, LOGL_ERROR,
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"Invalid punct2 value for coding scheme %d: %d\n",
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CodingScheme(cs), punct2);
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return -1;
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}
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/* fall through */
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case MCS6:
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case MCS5:
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case MCS4:
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case MCS3:
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case MCS2:
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case MCS1:
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if (punct == EGPRS_PS_INVALID) {
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LOGP(DRLCMACDL, LOGL_ERROR,
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"Invalid punct value for coding scheme %d: %d\n",
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CodingScheme(cs), punct);
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return -1;
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}
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break;
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default:
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return -1;
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}
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/* See 3GPP TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 */
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switch (CodingScheme(cs)) {
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case MCS1: return 0b1011 +
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punct % EGPRS_MAX_PS_NUM_2;
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case MCS2: return 0b1001 +
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punct % EGPRS_MAX_PS_NUM_2;
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case MCS3: return (with_padding ? 0b0110 : 0b0011) +
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punct % EGPRS_MAX_PS_NUM_3;
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case MCS4: return 0b0000 +
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punct % EGPRS_MAX_PS_NUM_3;
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case MCS5: return 0b100 +
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punct % EGPRS_MAX_PS_NUM_2;
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case MCS6: return (with_padding ? 0b010 : 0b000) +
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punct % EGPRS_MAX_PS_NUM_2;
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case MCS7: return 0b10100 +
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3 * (punct % EGPRS_MAX_PS_NUM_3) +
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punct2 % EGPRS_MAX_PS_NUM_3;
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case MCS8: return 0b01011 +
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3 * (punct % EGPRS_MAX_PS_NUM_3) +
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punct2 % EGPRS_MAX_PS_NUM_3;
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case MCS9: return 0b00000 +
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4 * (punct % EGPRS_MAX_PS_NUM_3) +
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punct2 % EGPRS_MAX_PS_NUM_3;
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default: ;
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}
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return -1;
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}
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void gprs_rlc_mcs_cps_decode(unsigned int cps,
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GprsCodingScheme cs, int *punct, int *punct2, int *with_padding)
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{
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*punct2 = -1;
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*with_padding = 0;
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switch (CodingScheme(cs)) {
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case MCS1:
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cps -= 0b1011; *punct = cps % 2; break;
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case MCS2:
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cps -= 0b1001; *punct = cps % 2; break;
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case MCS3:
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cps -= 0b0011; *punct = cps % 3; *with_padding = cps >= 3; break;
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case MCS4:
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cps -= 0b0000; *punct = cps % 3; break;
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case MCS5:
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cps -= 0b100; *punct = cps % 2; break;
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case MCS6:
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cps -= 0b000; *punct = cps % 2; *with_padding = cps >= 2; break;
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case MCS7:
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cps -= 0b10100; *punct = cps / 3; *punct2 = cps % 3; break;
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case MCS8:
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cps -= 0b01011; *punct = cps / 3; *punct2 = cps % 3; break;
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case MCS9:
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cps -= 0b00000; *punct = cps / 4; *punct2 = cps % 3; break;
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default: ;
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}
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}
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/*
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* Finds the PS value for retransmission with MCS change,
|
|
* retransmission with no MCS change, fresh transmission cases.
|
|
* The return value shall be used for current transmission only
|
|
* 44.060 9.3.2.1 defines the PS selection for MCS change case
|
|
* cs_current is the output of MCS selection algorithm for retx
|
|
* cs is coding scheme of previous transmission of RLC data block
|
|
*/
|
|
enum egprs_puncturing_values gprs_get_punct_scheme(
|
|
enum egprs_puncturing_values punct,
|
|
const GprsCodingScheme &cs,
|
|
const GprsCodingScheme &cs_current,
|
|
const enum egprs_rlcmac_dl_spb spb)
|
|
{
|
|
|
|
/*
|
|
* 10.4.8b of TS 44.060
|
|
* If it is second segment of the block
|
|
* dont change the puncturing scheme
|
|
*/
|
|
if (spb == EGPRS_RLCMAC_DL_SEC_SEG)
|
|
return punct;
|
|
|
|
/* TS 44.060 9.3.2.1.1 */
|
|
if ((CodingScheme(cs) == MCS9) &&
|
|
(CodingScheme(cs_current) == MCS6)) {
|
|
if ((punct == EGPRS_PS_1) || (punct == EGPRS_PS_3))
|
|
return EGPRS_PS_1;
|
|
else if (punct == EGPRS_PS_2)
|
|
return EGPRS_PS_2;
|
|
} else if ((CodingScheme(cs) == MCS6) &&
|
|
(CodingScheme(cs_current) == MCS9)) {
|
|
if (punct == EGPRS_PS_1)
|
|
return EGPRS_PS_3;
|
|
else if (punct == EGPRS_PS_2)
|
|
return EGPRS_PS_2;
|
|
} else if ((CodingScheme(cs) == MCS7) &&
|
|
(CodingScheme(cs_current) == MCS5))
|
|
return EGPRS_PS_1;
|
|
else if ((CodingScheme(cs) == MCS5) &&
|
|
(CodingScheme(cs_current) == MCS7))
|
|
return EGPRS_PS_2;
|
|
else if (cs != cs_current)
|
|
return EGPRS_PS_1;
|
|
/* TS 44.060 9.3.2.1.1 ends here */
|
|
/*
|
|
* Below else will handle fresh transmission, retransmission with no
|
|
* MCS change case
|
|
*/
|
|
else
|
|
return punct;
|
|
return EGPRS_PS_INVALID;
|
|
}
|
|
|
|
/*
|
|
* This function calculates puncturing scheme for retransmission of a RLC
|
|
* block with same MCS. The computed value shall be used for next transmission
|
|
* of the same RLC block
|
|
* TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
|
|
*/
|
|
void gprs_update_punct_scheme(enum egprs_puncturing_values *punct,
|
|
const GprsCodingScheme &cs)
|
|
{
|
|
switch (CodingScheme(cs)) {
|
|
case MCS1 :
|
|
case MCS2 :
|
|
case MCS5 :
|
|
case MCS6 :
|
|
*punct = ((enum egprs_puncturing_values)((*punct + 1) %
|
|
EGPRS_MAX_PS_NUM_2));
|
|
break;
|
|
case MCS3 :
|
|
case MCS4 :
|
|
case MCS7 :
|
|
case MCS8 :
|
|
case MCS9 :
|
|
*punct = ((enum egprs_puncturing_values)((*punct + 1) %
|
|
EGPRS_MAX_PS_NUM_3));
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|