From ae4838101a58feb512e88325efcae79f46af8e32 Mon Sep 17 00:00:00 2001 From: Max Date: Thu, 28 Jul 2016 12:03:08 +0200 Subject: Handle Timing Advance IE properly Move writing Timing Advance IE and Timing Advance Index into separate functions to simplify adding PTCCH support. This also fixes previous incorrect (and unused) code for writing Packet TA IE which has not set TS for TA. Change-Id: I786bf7fc999d401cc3d9e7f1e7a1fba953b5d458 Related: OS#1545 --- src/encoding.cpp | 74 ++++++++++++++++++++++++++++++++------------------------ 1 file changed, 43 insertions(+), 31 deletions(-) diff --git a/src/encoding.cpp b/src/encoding.cpp index 7d3fa144..fb80eeba 100644 --- a/src/encoding.cpp +++ b/src/encoding.cpp @@ -35,6 +35,43 @@ extern "C" { #include #include +/* { 0 | 1 < TIMING_ADVANCE_INDEX : bit (4) > } */ +static inline bool write_tai(bitvec *dest, unsigned& wp, int8_t tai) +{ + if (tai < 0) { /* No TIMING_ADVANCE_INDEX: */ + bitvec_write_field(dest, wp, 0, 1); + return false; + } + /* TIMING_ADVANCE_INDEX: */ + bitvec_write_field(dest, wp, 1, 1); + bitvec_write_field(dest, wp, tai, 4); + return true; +} + +/* { 0 | 1 < TIMING_ADVANCE_VALUE : bit (6) > } */ +static inline void write_ta(bitvec *dest, unsigned& wp, int8_t ta) +{ + if (ta < 0) /* No TIMING_ADVANCE_VALUE: */ + bitvec_write_field(dest, wp, 0, 1); + else { /* TIMING_ADVANCE_VALUE: */ + bitvec_write_field(dest, wp, 1, 1); + bitvec_write_field(dest, wp, ta, 6); + } +} + +/* 3GPP TS 44.060 ยง 12.12: + { 0 | 1 < TIMING_ADVANCE_VALUE : bit (6) > } + { 0 | 1 < TIMING_ADVANCE_INDEX : bit (4) > + < TIMING_ADVANCE_TIMESLOT_NUMBER : bit (3) > } + */ +static inline void write_ta_ie(bitvec *dest, unsigned& wp, + int8_t ta, int8_t tai, uint8_t ts) +{ + write_ta(dest, wp, ta); + if (write_tai(dest, wp, tai)) /* TIMING_ADVANCE_TIMESLOT_NUMBER: */ + bitvec_write_field(dest, wp, ts, 3); +} + static int write_ia_rest_downlink( gprs_rlcmac_dl_tbf *tbf, bitvec * dest, unsigned& wp, @@ -62,12 +99,7 @@ static int write_ia_rest_downlink( 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, ta_valid, 1); // N. B: NOT related to TAI! - 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 - } + write_tai(dest, wp, ta_idx); if (polling) { bitvec_write_field(dest, wp,0x1,1); // TBF Starting TIME present bitvec_write_field(dest, wp,(fn / (26 * 51)) % 32,5); // T1' @@ -110,12 +142,7 @@ static int write_ia_rest_uplink( } 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 - } + write_tai(dest, wp, ta_idx); 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 @@ -311,6 +338,8 @@ void Encoding::write_packet_uplink_assignment( // TODO We should use our implementation of encode RLC/MAC Control messages. unsigned wp = 0; uint8_t ts; + /* timeslot assigned for the Continuous Timing Advance procedure */ + uint8_t ta_ts = 0; /* FIXME: supply it as parameter from caller */ bitvec_write_field(dest, wp,0x1,2); // Payload Type bitvec_write_field(dest, wp,0x0,2); // Uplink block with TDMA framenumber (N+13) @@ -334,15 +363,7 @@ void Encoding::write_packet_uplink_assignment( bitvec_write_field(dest, wp,0x0,1); // Message escape bitvec_write_field(dest, wp,tbf->current_cs().to_num()-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 - } - + write_ta_ie(dest, wp,tbf->ta(), ta_idx, ta_ts); } else { /* EPGRS */ unsigned int ws_enc = (tbf->m_window.ws() - 64) / 32; bitvec_write_field(dest, wp,0x1,1); // Message escape @@ -357,16 +378,7 @@ void Encoding::write_packet_uplink_assignment( 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 - } - + write_ta_ie(dest, wp,tbf->ta(), ta_idx, ta_ts); bitvec_write_field(dest, wp,0x0,1); // No Packet Extended Timing Advance } -- cgit v1.2.3