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osmo-pcu/src/encoding.cpp

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/* encoding.cpp
*
* Copyright (C) 2012 Ivan Klyuchnikov
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
* Copyright (C) 2013 by Holger Hans Peter Freyther
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <encoding.h>
#include <gprs_rlcmac.h>
#include <bts.h>
#include <tbf.h>
#include <gprs_debug.h>
// GSM 04.08 9.1.18 Immediate assignment
int Encoding::write_immediate_assignment(
struct gprs_rlcmac_bts *bts,
bitvec * dest, uint8_t downlink, uint8_t ra,
uint32_t ref_fn, uint8_t ta, uint16_t arfcn, uint8_t ts, uint8_t tsc,
uint8_t tfi, uint8_t usf, uint32_t tlli,
uint8_t polling, uint32_t fn, uint8_t single_block, uint8_t alpha,
uint8_t gamma, int8_t ta_idx)
{
unsigned wp = 0;
uint8_t plen;
bitvec_write_field(dest, wp,0x0,4); // Skip Indicator
bitvec_write_field(dest, wp,0x6,4); // Protocol Discriminator
bitvec_write_field(dest, wp,0x3F,8); // Immediate Assignment Message Type
// 10.5.2.25b Dedicated mode or TBF
bitvec_write_field(dest, wp,0x0,1); // spare
bitvec_write_field(dest, wp,0x0,1); // TMA : Two-message assignment: No meaning
bitvec_write_field(dest, wp,downlink,1); // Downlink : Downlink assignment to mobile in packet idle mode
bitvec_write_field(dest, wp,0x1,1); // T/D : TBF or dedicated mode: this message assigns a Temporary Block Flow (TBF).
bitvec_write_field(dest, wp,0x0,4); // Page Mode
// GSM 04.08 10.5.2.25a Packet Channel Description
bitvec_write_field(dest, wp,0x1,5); // Channel type
bitvec_write_field(dest, wp,ts,3); // TN
bitvec_write_field(dest, wp,tsc,3); // TSC
bitvec_write_field(dest, wp,0x0,3); // non-hopping RF channel configuraion
bitvec_write_field(dest, wp,arfcn,10); // ARFCN
//10.5.2.30 Request Reference
bitvec_write_field(dest, wp,ra,8); // RA
bitvec_write_field(dest, wp,(ref_fn / (26 * 51)) % 32,5); // T1'
bitvec_write_field(dest, wp,ref_fn % 51,6); // T3
bitvec_write_field(dest, wp,ref_fn % 26,5); // T2
// 10.5.2.40 Timing Advance
bitvec_write_field(dest, wp,0x0,2); // spare
bitvec_write_field(dest, wp,ta,6); // Timing Advance value
// No mobile allocation in non-hopping systems.
// A zero-length LV. Just write L=0.
bitvec_write_field(dest, wp,0,8);
if ((wp % 8)) {
LOGP(DRLCMACUL, LOGL_ERROR, "Length of IMM.ASS without rest "
"octets is not multiple of 8 bits, PLEASE FIX!\n");
exit (0);
}
plen = wp / 8;
if (downlink)
{
// GSM 04.08 10.5.2.16 IA Rest Octets
bitvec_write_field(dest, wp, 3, 2); // "HH"
bitvec_write_field(dest, wp, 1, 2); // "01" Packet Downlink Assignment
bitvec_write_field(dest, wp,tlli,32); // TLLI
bitvec_write_field(dest, wp,0x1,1); // switch TFI : on
bitvec_write_field(dest, wp,tfi,5); // TFI
bitvec_write_field(dest, wp,0x0,1); // RLC acknowledged mode
if (alpha) {
bitvec_write_field(dest, wp,0x1,1); // ALPHA = present
bitvec_write_field(dest, wp,alpha,4); // ALPHA
} else {
bitvec_write_field(dest, wp,0x0,1); // ALPHA = not present
}
bitvec_write_field(dest, wp,gamma,5); // GAMMA power control parameter
bitvec_write_field(dest, wp,polling,1); // Polling Bit
bitvec_write_field(dest, wp,!polling,1); // TA_VALID ???
if (ta_idx < 0) {
bitvec_write_field(dest, wp,0x0,1); // switch TIMING_ADVANCE_INDEX = off
} else {
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_INDEX = on
bitvec_write_field(dest, wp,ta_idx,4); // TIMING_ADVANCE_INDEX
}
if (polling) {
bitvec_write_field(dest, wp,0x1,1); // TBF Starting TIME present
bitvec_write_field(dest, wp,(fn / (26 * 51)) % 32,5); // T1'
bitvec_write_field(dest, wp,fn % 51,6); // T3
bitvec_write_field(dest, wp,fn % 26,5); // T2
} else {
bitvec_write_field(dest, wp,0x0,1); // TBF Starting TIME present
}
bitvec_write_field(dest, wp,0x0,1); // P0 not present
// bitvec_write_field(dest, wp,0x1,1); // P0 not present
// bitvec_write_field(dest, wp,0xb,4);
}
else
{
// GMS 04.08 10.5.2.37b 10.5.2.16
bitvec_write_field(dest, wp, 3, 2); // "HH"
bitvec_write_field(dest, wp, 0, 2); // "0" Packet Uplink Assignment
if (single_block) {
bitvec_write_field(dest, wp, 0, 1); // Block Allocation : Single Block Allocation
if (alpha) {
bitvec_write_field(dest, wp,0x1,1); // ALPHA = present
bitvec_write_field(dest, wp,alpha,4); // ALPHA = present
} else
bitvec_write_field(dest, wp,0x0,1); // ALPHA = not present
bitvec_write_field(dest, wp,gamma,5); // GAMMA power control parameter
if (ta_idx < 0) {
bitvec_write_field(dest, wp,0x0,1); // switch TIMING_ADVANCE_INDEX = off
} else {
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_INDEX = on
bitvec_write_field(dest, wp,ta_idx,4); // TIMING_ADVANCE_INDEX
}
bitvec_write_field(dest, wp, 1, 1); // TBF_STARTING_TIME_FLAG
bitvec_write_field(dest, wp,(fn / (26 * 51)) % 32,5); // T1'
bitvec_write_field(dest, wp,fn % 51,6); // T3
bitvec_write_field(dest, wp,fn % 26,5); // T2
} else {
bitvec_write_field(dest, wp, 1, 1); // Block Allocation : Not Single Block Allocation
bitvec_write_field(dest, wp, tfi, 5); // TFI_ASSIGNMENT Temporary Flow Identity
bitvec_write_field(dest, wp, 0, 1); // POLLING
bitvec_write_field(dest, wp, 0, 1); // ALLOCATION_TYPE: dynamic
bitvec_write_field(dest, wp, usf, 3); // USF
bitvec_write_field(dest, wp, 0, 1); // USF_GRANULARITY
bitvec_write_field(dest, wp, 0, 1); // "0" power control: Not Present
bitvec_write_field(dest, wp, bts->initial_cs_ul-1, 2); // CHANNEL_CODING_COMMAND
bitvec_write_field(dest, wp, 1, 1); // TLLI_BLOCK_CHANNEL_CODING
if (alpha) {
bitvec_write_field(dest, wp,0x1,1); // ALPHA = present
bitvec_write_field(dest, wp,alpha,4); // ALPHA
} else
bitvec_write_field(dest, wp,0x0,1); // ALPHA = not present
bitvec_write_field(dest, wp,gamma,5); // GAMMA power control parameter
/* note: there is no choise for TAI and no starting time */
bitvec_write_field(dest, wp, 0, 1); // switch TIMING_ADVANCE_INDEX = off
bitvec_write_field(dest, wp, 0, 1); // TBF_STARTING_TIME_FLAG
}
}
return plen;
}
/* generate uplink assignment */
void Encoding::write_packet_uplink_assignment(
struct gprs_rlcmac_bts *bts,
bitvec * dest, uint8_t old_tfi,
uint8_t old_downlink, uint32_t tlli, uint8_t use_tlli,
struct gprs_rlcmac_ul_tbf *tbf, uint8_t poll, uint8_t alpha,
uint8_t gamma, int8_t ta_idx, int8_t use_egprs)
{
// TODO We should use our implementation of encode RLC/MAC Control messages.
unsigned wp = 0;
uint8_t ts;
bitvec_write_field(dest, wp,0x1,2); // Payload Type
bitvec_write_field(dest, wp,0x0,2); // Uplink block with TDMA framenumber (N+13)
bitvec_write_field(dest, wp,poll,1); // Suppl/Polling Bit
bitvec_write_field(dest, wp,0x0,3); // Uplink state flag
bitvec_write_field(dest, wp,0xa,6); // MESSAGE TYPE
bitvec_write_field(dest, wp,0x0,2); // Page Mode
bitvec_write_field(dest, wp,0x0,1); // switch PERSIST_LEVEL: off
if (use_tlli) {
bitvec_write_field(dest, wp,0x2,2); // switch TLLI : on
bitvec_write_field(dest, wp,tlli,32); // TLLI
} else {
bitvec_write_field(dest, wp,0x0,1); // switch TFI : on
bitvec_write_field(dest, wp,old_downlink,1); // 0=UPLINK TFI, 1=DL TFI
bitvec_write_field(dest, wp,old_tfi,5); // TFI
}
if (!use_egprs) {
bitvec_write_field(dest, wp,0x0,1); // Message escape
bitvec_write_field(dest, wp,tbf->current_cs()-1, 2); // CHANNEL_CODING_COMMAND
bitvec_write_field(dest, wp,0x1,1); // TLLI_BLOCK_CHANNEL_CODING
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_VALUE = on
bitvec_write_field(dest, wp,tbf->ta(),6); // TIMING_ADVANCE_VALUE
if (ta_idx < 0) {
bitvec_write_field(dest, wp,0x0,1); // switch TIMING_ADVANCE_INDEX = off
} else {
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_INDEX = on
bitvec_write_field(dest, wp,ta_idx,4); // TIMING_ADVANCE_INDEX
}
} else { /* EPGRS */
bitvec_write_field(dest, wp,0x1,1); // Message escape
bitvec_write_field(dest, wp,0x0,2); // EGPRS message contents
bitvec_write_field(dest, wp,0x0,1); // No CONTENTION_RESOLUTION_TLLI
bitvec_write_field(dest, wp,0x0,1); // No COMPACT reduced MA
bitvec_write_field(dest, wp,tbf->current_cs()-1, 4); // EGPRS Modulation and Coding IE
bitvec_write_field(dest, wp,0x0,1); // No RESEGMENT
bitvec_write_field(dest, wp,0x0,5); // EGPRS Window Size = 64
bitvec_write_field(dest, wp,0x0,1); // No Access Technologies Request
bitvec_write_field(dest, wp,0x0,1); // No ARAC RETRANSMISSION REQUEST
bitvec_write_field(dest, wp,0x1,1); // TLLI_BLOCK_CHANNEL_CODING
bitvec_write_field(dest, wp,0x0,1); // No BEP_PERIOD2
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_VALUE = on
bitvec_write_field(dest, wp,tbf->ta(),6); // TIMING_ADVANCE_VALUE
if (ta_idx < 0) {
bitvec_write_field(dest, wp,0x0,1); // switch TIMING_ADVANCE_INDEX = off
} else {
bitvec_write_field(dest, wp,0x1,1); // switch TIMING_ADVANCE_INDEX = on
bitvec_write_field(dest, wp,ta_idx,4); // TIMING_ADVANCE_INDEX
}
bitvec_write_field(dest, wp,0x0,1); // No Packet Extended Timing Advance
}
#if 1
bitvec_write_field(dest, wp,0x1,1); // Frequency Parameters information elements = present
bitvec_write_field(dest, wp,tbf->tsc(),3); // Training Sequence Code (TSC)
bitvec_write_field(dest, wp,0x0,2); // ARFCN = present
bitvec_write_field(dest, wp,tbf->trx->arfcn,10); // ARFCN
#else
bitvec_write_field(dest, wp,0x0,1); // Frequency Parameters = off
#endif
bitvec_write_field(dest, wp,0x1,2); // Dynamic Allocation
bitvec_write_field(dest, wp,0x0,1); // Extended Dynamic Allocation = off
bitvec_write_field(dest, wp,0x0,1); // P0 = off
bitvec_write_field(dest, wp,0x0,1); // USF_GRANULARITY
bitvec_write_field(dest, wp,0x1,1); // switch TFI : on
bitvec_write_field(dest, wp,tbf->tfi(),5);// TFI
bitvec_write_field(dest, wp,0x0,1); //
bitvec_write_field(dest, wp,0x0,1); // TBF Starting Time = off
if (alpha || gamma) {
bitvec_write_field(dest, wp,0x1,1); // Timeslot Allocation with Power Control
bitvec_write_field(dest, wp,alpha,4); // ALPHA
} else
bitvec_write_field(dest, wp,0x0,1); // Timeslot Allocation
for (ts = 0; ts < 8; ts++) {
if (tbf->pdch[ts]) {
bitvec_write_field(dest, wp,0x1,1); // USF_TN(i): on
bitvec_write_field(dest, wp,tbf->m_usf[ts],3); // USF_TN(i)
if (alpha || gamma)
bitvec_write_field(dest, wp,gamma,5); // GAMMA power control parameter
} else
bitvec_write_field(dest, wp,0x0,1); // USF_TN(i): off
}
// bitvec_write_field(dest, wp,0x0,1); // Measurement Mapping struct not present
}
/* generate downlink assignment */
void Encoding::write_packet_downlink_assignment(RlcMacDownlink_t * block, uint8_t old_tfi,
uint8_t old_downlink, struct gprs_rlcmac_tbf *tbf, uint8_t poll,
uint8_t alpha, uint8_t gamma, int8_t ta_idx, uint8_t ta_ts)
{
// Packet downlink assignment TS 44.060 11.2.7
uint8_t tn;
block->PAYLOAD_TYPE = 0x1; // RLC/MAC control block that does not include the optional octets of the RLC/MAC control header
block->RRBP = 0x0; // N+13
block->SP = poll; // RRBP field is valid
block->USF = 0x0; // Uplink state flag
block->u.Packet_Downlink_Assignment.MESSAGE_TYPE = 0x2; // Packet Downlink Assignment
block->u.Packet_Downlink_Assignment.PAGE_MODE = 0x0; // Normal Paging
block->u.Packet_Downlink_Assignment.Exist_PERSISTENCE_LEVEL = 0x0; // PERSISTENCE_LEVEL: off
block->u.Packet_Downlink_Assignment.ID.UnionType = 0x0; // TFI = on
block->u.Packet_Downlink_Assignment.ID.u.Global_TFI.UnionType = old_downlink; // 0=UPLINK TFI, 1=DL TFI
block->u.Packet_Downlink_Assignment.ID.u.Global_TFI.u.UPLINK_TFI = old_tfi; // TFI
block->u.Packet_Downlink_Assignment.MAC_MODE = 0x0; // Dynamic Allocation
block->u.Packet_Downlink_Assignment.RLC_MODE = 0x0; // RLC acknowledged mode
block->u.Packet_Downlink_Assignment.CONTROL_ACK = tbf->was_releasing; // NW establishes no new DL TBF for the MS with running timer T3192
block->u.Packet_Downlink_Assignment.TIMESLOT_ALLOCATION = 0; // timeslot(s)
for (tn = 0; tn < 8; tn++) {
if (tbf->pdch[tn])
block->u.Packet_Downlink_Assignment.TIMESLOT_ALLOCATION |= 0x80 >> tn; // timeslot(s)
}
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.Exist_TIMING_ADVANCE_VALUE = 0x1; // TIMING_ADVANCE_VALUE = on
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.TIMING_ADVANCE_VALUE = tbf->ta(); // TIMING_ADVANCE_VALUE
if (ta_idx < 0) {
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.Exist_IndexAndtimeSlot = 0x0; // TIMING_ADVANCE_INDEX = off
} else {
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.Exist_IndexAndtimeSlot = 0x1; // TIMING_ADVANCE_INDEX = on
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.TIMING_ADVANCE_INDEX = ta_idx; // TIMING_ADVANCE_INDEX
block->u.Packet_Downlink_Assignment.Packet_Timing_Advance.TIMING_ADVANCE_TIMESLOT_NUMBER = ta_ts; // TIMING_ADVANCE_TS
}
block->u.Packet_Downlink_Assignment.Exist_P0_and_BTS_PWR_CTRL_MODE = 0x0; // POWER CONTROL = off
block->u.Packet_Downlink_Assignment.Exist_Frequency_Parameters = 0x1; // Frequency Parameters = on
block->u.Packet_Downlink_Assignment.Frequency_Parameters.TSC = tbf->tsc(); // Training Sequence Code (TSC)
block->u.Packet_Downlink_Assignment.Frequency_Parameters.UnionType = 0x0; // ARFCN = on
block->u.Packet_Downlink_Assignment.Frequency_Parameters.u.ARFCN = tbf->trx->arfcn; // ARFCN
block->u.Packet_Downlink_Assignment.Exist_DOWNLINK_TFI_ASSIGNMENT = 0x1; // DOWNLINK TFI ASSIGNMENT = on
block->u.Packet_Downlink_Assignment.DOWNLINK_TFI_ASSIGNMENT = tbf->tfi(); // TFI
block->u.Packet_Downlink_Assignment.Exist_Power_Control_Parameters = 0x1; // Power Control Parameters = on
block->u.Packet_Downlink_Assignment.Power_Control_Parameters.ALPHA = alpha; // ALPHA
for (tn = 0; tn < 8; tn++)
{
if (tbf->pdch[tn])
{
block->u.Packet_Downlink_Assignment.Power_Control_Parameters.Slot[tn].Exist = 0x1; // Slot[i] = on
block->u.Packet_Downlink_Assignment.Power_Control_Parameters.Slot[tn].GAMMA_TN = gamma; // GAMMA_TN
}
else
{
block->u.Packet_Downlink_Assignment.Power_Control_Parameters.Slot[tn].Exist = 0x0; // Slot[i] = off
}
}
block->u.Packet_Downlink_Assignment.Exist_TBF_Starting_Time = 0x0; // TBF Starting TIME = off
block->u.Packet_Downlink_Assignment.Exist_Measurement_Mapping = 0x0; // Measurement_Mapping = off
block->u.Packet_Downlink_Assignment.Exist_AdditionsR99 = 0x0; // AdditionsR99 = off
}
/* generate paging request */
int Encoding::write_paging_request(bitvec * dest, uint8_t *ptmsi, uint16_t ptmsi_len)
{
unsigned wp = 0;
int plen;
bitvec_write_field(dest, wp,0x0,4); // Skip Indicator
bitvec_write_field(dest, wp,0x6,4); // Protocol Discriminator
bitvec_write_field(dest, wp,0x21,8); // Paging Request Message Type
bitvec_write_field(dest, wp,0x0,4); // Page Mode
bitvec_write_field(dest, wp,0x0,4); // Channel Needed
// Mobile Identity
bitvec_write_field(dest, wp,ptmsi_len+1,8); // Mobile Identity length
bitvec_write_field(dest, wp,0xf,4); // unused
bitvec_write_field(dest, wp,0x4,4); // PTMSI type
for (int i = 0; i < ptmsi_len; i++)
{
bitvec_write_field(dest, wp,ptmsi[i],8); // PTMSI
}
if ((wp % 8)) {
LOGP(DRLCMACUL, LOGL_ERROR, "Length of PAG.REQ without rest "
"octets is not multiple of 8 bits, PLEASE FIX!\n");
exit (0);
}
plen = wp / 8;
bitvec_write_field(dest, wp,0x0,1); // "L" NLN(PCH) = off
bitvec_write_field(dest, wp,0x0,1); // "L" Priority1 = off
bitvec_write_field(dest, wp,0x1,1); // "L" Priority2 = off
bitvec_write_field(dest, wp,0x0,1); // "L" Group Call information = off
bitvec_write_field(dest, wp,0x0,1); // "H" Packet Page Indication 1 = packet paging procedure
bitvec_write_field(dest, wp,0x1,1); // "H" Packet Page Indication 2 = packet paging procedure
return plen;
}
/**
* The index of the array show_rbb is the bit position inside the rbb
* (show_rbb[63] relates to BSN ssn-1)
*/
void Encoding::encode_rbb(const char *show_rbb, uint8_t *rbb)
{
uint8_t rbb_byte = 0;
// RECEIVE_BLOCK_BITMAP
for (int i = 0; i < 64; i++) {
/* Set bit at the appropriate position (see 3GPP TS 04.60 9.1.8.1) */
if (show_rbb[i] == 'R')
rbb_byte |= 1<< (7-(i%8));
if((i%8) == 7) {
rbb[i/8] = rbb_byte;
rbb_byte = 0;
}
}
}
static void write_packet_ack_nack_desc_gprs(
struct gprs_rlcmac_bts *bts, bitvec * dest, unsigned& wp,
gprs_rlc_ul_window *window, bool is_final)
{
char rbb[65];
window->update_rbb(rbb);
rbb[64] = 0;
LOGP(DRLCMACUL, LOGL_DEBUG, "- V(N): \"%s\" R=Received "
"I=Invalid\n", rbb);
bitvec_write_field(dest, wp, is_final, 1); // FINAL_ACK_INDICATION
bitvec_write_field(dest, wp, window->ssn(), 7); // STARTING_SEQUENCE_NUMBER
for (int i = 0; i < 64; i++) {
/* Set bit at the appropriate position (see 3GPP TS 04.60 9.1.8.1) */
bool is_ack = (rbb[i] == 'R');
bitvec_write_field(dest, wp, is_ack, 1);
}
}
static void write_packet_uplink_ack_gprs(
struct gprs_rlcmac_bts *bts, bitvec * dest, unsigned& wp,
struct gprs_rlcmac_ul_tbf *tbf, bool is_final)
{
bitvec_write_field(dest, wp, tbf->current_cs() - 1, 2); // CHANNEL_CODING_COMMAND
write_packet_ack_nack_desc_gprs(bts, dest, wp, &tbf->m_window, is_final);
bitvec_write_field(dest, wp, 1, 1); // 1: have CONTENTION_RESOLUTION_TLLI
bitvec_write_field(dest, wp, tbf->tlli(), 32); // CONTENTION_RESOLUTION_TLLI
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Packet Timing Advance
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Power Control Parameters
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Extension Bits
bitvec_write_field(dest, wp, 0, 1); // fixed 0
bitvec_write_field(dest, wp, 1, 1); // 1: have Additions R99
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Packet Extended Timing Advance
bitvec_write_field(dest, wp, 1, 1); // TBF_EST (enabled)
bitvec_write_field(dest, wp, 0, 1); // 0: don't have REL 5
};
static void write_packet_ack_nack_desc_egprs(
struct gprs_rlcmac_bts *bts, bitvec * dest, unsigned& wp,
gprs_rlc_ul_window *window, bool is_final)
{
int urbb_len = 0;
int crbb_len = 0;
int len;
bool bow = true;
bool eow = true;
int ssn = window->mod_sns(window->v_q() + 1);
int num_blocks = window->mod_sns(window->v_r() - window->v_q());
int esn_crbb = window->mod_sns(ssn - 1);
int rest_bits = dest->data_len * 8 - wp;
if (num_blocks > 0)
/* V(Q) is NACK and omitted -> SSN = V(Q) + 1 */
num_blocks -= 1;
if (num_blocks > window->ws())
num_blocks = window->ws();
if (num_blocks > rest_bits) {
eow = false;
urbb_len = rest_bits;
/* TODO: use compression, start encoding bits and stop when the
* space is exhausted. Use the first combination that encodes
* all bits. If there is none, use the combination that encodes
* the largest number of bits (e.g. by setting num_blocks to the
* max and repeating the construction).
*/
} else if (num_blocks > rest_bits - 9) {
/* union bit and length field take 9 bits */
eow = false;
urbb_len = rest_bits - 9;
/* TODO: use compression (see above) */
}
if (urbb_len + crbb_len == rest_bits)
len = -1;
else if (crbb_len == 0)
len = urbb_len + 15;
else
len = urbb_len + crbb_len + 23;
/* EGPRS Ack/Nack Description IE */
if (len < 0) {
bitvec_write_field(dest, wp, 0, 1); // 0: don't have length
} else {
bitvec_write_field(dest, wp, 1, 1); // 1: have length
bitvec_write_field(dest, wp, len, 8); // length
}
bitvec_write_field(dest, wp, is_final, 1); // FINAL_ACK_INDICATION
bitvec_write_field(dest, wp, bow, 1); // BEGINNING_OF_WINDOW
bitvec_write_field(dest, wp, eow, 1); // END_OF_WINDOW
bitvec_write_field(dest, wp, ssn, 11); // STARTING_SEQUENCE_NUMBER
bitvec_write_field(dest, wp, 0, 1); // 0: don't have CRBB
/* TODO: Add CRBB support */
LOGP(DRLCMACUL, LOGL_DEBUG,
" - EGPRS URBB, len = %d, SSN = %d, ESN_CRBB = %d, "
"SNS = %d, WS = %d, V(Q) = %d, V(R) = %d%s%s\n",
urbb_len, ssn, esn_crbb,
window->sns(), window->ws(), window->v_q(), window->v_r(),
bow ? ", BOW" : "", eow ? ", EOW" : "");
for (int i = urbb_len; i > 0; i--) {
/* Set bit at the appropriate position (see 3GPP TS 04.60 12.3.1) */
bool is_ack = window->m_v_n.is_received(esn_crbb + i);
bitvec_write_field(dest, wp, is_ack, 1);
}
}
static void write_packet_uplink_ack_egprs(
struct gprs_rlcmac_bts *bts, bitvec * dest, unsigned& wp,
struct gprs_rlcmac_ul_tbf *tbf, bool is_final)
{
bitvec_write_field(dest, wp, 0, 2); // fixed 00
bitvec_write_field(dest, wp, 2, 4); // CHANNEL_CODING_COMMAND: MCS-3
// bitvec_write_field(dest, wp, tbf->current_cs() - 1, 4); // CHANNEL_CODING_COMMAND
bitvec_write_field(dest, wp, 0, 1); // 0: no RESEGMENT (nyi)
bitvec_write_field(dest, wp, 1, 1); // PRE_EMPTIVE_TRANSMISSION, TODO: This resembles GPRS, change it?
bitvec_write_field(dest, wp, 0, 1); // 0: no PRR_RETRANSMISSION_REQUEST, TODO: clarify
bitvec_write_field(dest, wp, 0, 1); // 0: no ARAC_RETRANSMISSION_REQUEST, TODO: clarify
bitvec_write_field(dest, wp, 1, 1); // 1: have CONTENTION_RESOLUTION_TLLI
bitvec_write_field(dest, wp, tbf->tlli(), 32); // CONTENTION_RESOLUTION_TLLI
bitvec_write_field(dest, wp, 1, 1); // TBF_EST (enabled)
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Packet Timing Advance
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Packet Extended Timing Advance
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Power Control Parameters
bitvec_write_field(dest, wp, 0, 1); // 0: don't have Extension Bits
write_packet_ack_nack_desc_egprs(bts, dest, wp, &tbf->m_window, is_final);
bitvec_write_field(dest, wp, 0, 1); // fixed 0
bitvec_write_field(dest, wp, 0, 1); // 0: don't have REL 5
};
void Encoding::write_packet_uplink_ack(
struct gprs_rlcmac_bts *bts, bitvec * dest,
struct gprs_rlcmac_ul_tbf *tbf, bool is_final)
{
unsigned wp = 0;
LOGP(DRLCMACUL, LOGL_DEBUG, "Encoding Ack/Nack for %s "
"(final=%d)\n", tbf_name(tbf), is_final);
bitvec_write_field(dest, wp, 0x1, 2); // Payload Type
bitvec_write_field(dest, wp, 0x0, 2); // Uplink block with TDMA framenumber (N+13)
bitvec_write_field(dest, wp, is_final, 1); // Suppl/Polling Bit
bitvec_write_field(dest, wp, 0x0, 3); // Uplink state flag
bitvec_write_field(dest, wp, 0x9, 6); // MESSAGE TYPE Uplink Ack/Nack
bitvec_write_field(dest, wp, 0x0, 2); // Page Mode
bitvec_write_field(dest, wp, 0x0, 2); // fixed 00
bitvec_write_field(dest, wp, tbf->tfi(), 5); // Uplink TFI
if (tbf->is_egprs_enabled()) {
/* PU_AckNack_EGPRS = on */
bitvec_write_field(dest, wp, 1, 1); // 1: EGPRS
write_packet_uplink_ack_egprs(bts, dest, wp, tbf, is_final);
} else {
/* PU_AckNack_GPRS = on */
bitvec_write_field(dest, wp, 0, 1); // 0: GPRS
write_packet_uplink_ack_gprs(bts, dest, wp, tbf, is_final);
}
LOGP(DRLCMACUL, LOGL_DEBUG,
"Uplink Ack/Nack bit count %d, max %d, message = %s\n",
wp, dest->data_len * 8,
osmo_hexdump(dest->data, dest->data_len));
}
unsigned Encoding::write_packet_paging_request(bitvec * dest)
{
unsigned wp = 0;
bitvec_write_field(dest, wp,0x1,2); // Payload Type
bitvec_write_field(dest, wp,0x0,3); // No polling
bitvec_write_field(dest, wp,0x0,3); // Uplink state flag
bitvec_write_field(dest, wp,0x22,6); // MESSAGE TYPE
bitvec_write_field(dest, wp,0x0,2); // Page Mode
bitvec_write_field(dest, wp,0x0,1); // No PERSISTENCE_LEVEL
bitvec_write_field(dest, wp,0x0,1); // No NLN
return wp;
}
unsigned Encoding::write_repeated_page_info(bitvec * dest, unsigned& wp, uint8_t len,
uint8_t *identity, uint8_t chan_needed)
{
bitvec_write_field(dest, wp,0x1,1); // Repeated Page info exists
bitvec_write_field(dest, wp,0x1,1); // RR connection paging
if ((identity[0] & 0x07) == 4) {
bitvec_write_field(dest, wp,0x0,1); // TMSI
identity++;
len--;
} else {
bitvec_write_field(dest, wp,0x0,1); // MI
bitvec_write_field(dest, wp,len,4); // MI len
}
while (len) {
bitvec_write_field(dest, wp,*identity++,8); // MI data
len--;
}
bitvec_write_field(dest, wp,chan_needed,2); // CHANNEL_NEEDED
bitvec_write_field(dest, wp,0x0,1); // No eMLPP_PRIORITY
return wp;
}
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