[M] Change in libosmocore[master]: Interleaving for CSD

laforge has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/31529 ) Change subject: Interleaving for CSD ...................................................................... Interleaving for CSD This patch adds the [de]interleaving for CSD (circuit switched data), nominally for TCH/F 9.6, but the same is also used for TCH/F 4.8, TCH/H 4.8, TCH/F 2.4 and TCH/F 14.4. Related: OS#4396, OS#1572 Change-Id: I6b16c2d0d7febf3883da662b2c7fec543335de12 --- M src/coding/gsm0503_interleaving.c M src/coding/libosmocoding.map 2 files changed, 68 insertions(+), 0 deletions(-) Approvals: fixeria: Looks good to me, but someone else must approve pespin: Looks good to me, approved Jenkins Builder: Verified diff --git a/src/coding/gsm0503_interleaving.c b/src/coding/gsm0503_interleaving.c index 7809e83..cd2f235 100644 --- a/src/coding/gsm0503_interleaving.c +++ b/src/coding/gsm0503_interleaving.c @@ -678,4 +678,56 @@ } } +/* 3GPP TS 45.003 Section 3.3.4 + * The coded bits are reordered and interleaved according to the following rule: + * i(B,j) = c(n,k) for k = 0,1,...,455 + * n = 0,1,...,N,N + 1,... + * B = B0 +4n + (k mod 19) + (k div 114) + * j = (k mod 19) + 19 (k mod 6) + * + * The result of the interleaving is a distribution of the reordered 114 + * bit of a given data block, n = N, over 19 blocks, 6 bits equally + * distributed in each block, in a diagonal way over consecutive blocks. + * + * Or in other words the interleaving is a distribution of the encoded, + * reordered 456 bits from four given input data blocks, which taken + * together give n = N, over 22 bursts, 6 bits equally distributed in + * the first and 22 nd bursts, 12 bits distributed in the second and 21 + * st bursts, 18 bits distributed in the third and 20 th bursts and 24 + * bits distributed in the other 16 bursts. + * + * The block of coded data is interleaved "diagonal", where a new block + * of coded data starts with every fourth burst and is distributed over + * 22 bursts. + * + * Also used for TCH/F4.8, TCH/H4.8, TCH/F2.4 and TCH/H2.4 and TCH/F14.4 */ +void gsm0503_tch_f96_interleave(const ubit_t *cB, ubit_t *iB) +{ + int j, k, B; + + for (k = 0; k < 456; k++) { + /* upper bound for B: 4*n + 18 + 4 = 4*n + 22 */ + B = /* B0 + 4n + */ (k % 19) + (k / 114); + /* upper bound for j: 18 + 19*5 = 113 */ + j = (k % 19) + 19 * (k % 6); + /* upper iB index: 4*n+23*114-1 */ + iB[B * 114 + j] = cB[k]; + } +} + +void gsm0503_tch_f96_deinterleave(sbit_t *cB, const sbit_t *iB) +{ + int j, k, B; + + for (k = 0; k < 456; k++) { + /* upper bound for B: 4*n + 18 + 4 = 4*n + 22 */ + B = /* B0 + 4n + */ (k % 19) + (k / 114); + /* upper bound for j: 18 + 19*5 = 113 */ + j = (k % 19) + 19 * (k % 6); + /* upper iB index: 4*n+23*114-1 */ + cB[k] = iB[B * 114 + j]; + } +} + + /*! @} */ diff --git a/src/coding/libosmocoding.map b/src/coding/libosmocoding.map index b083564..ff6ea80 100644 --- a/src/coding/libosmocoding.map +++ b/src/coding/libosmocoding.map @@ -76,6 +76,8 @@ gsm0503_xcch_interleave; gsm0503_tch_fr_deinterleave; gsm0503_tch_fr_interleave; +gsm0503_tch_f96_deinterleave; +gsm0503_tch_f96_interleave; gsm0503_tch_hr_deinterleave; gsm0503_tch_hr_interleave; gsm0503_mcs1_ul_deinterleave; -- To view, visit https://gerrit.osmocom.org/c/libosmocore/+/31529 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: libosmocore Gerrit-Branch: master Gerrit-Change-Id: I6b16c2d0d7febf3883da662b2c7fec543335de12 Gerrit-Change-Number: 31529 Gerrit-PatchSet: 4 Gerrit-Owner: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria &lt;vyanitskiy(a)sysmocom.de&gt; Gerrit-Reviewer: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-CC: msuraev &lt;msuraev(a)sysmocom.de&gt; Gerrit-MessageType: merged