coding: implement TCH/F9.6, TCH/[FH]4.8, TCH/H2.4, TCH/F14.4
Implement all CSD specific channel modes, except TCH/F2.4. All of
these modes are more or less similar to each other. The TCH/F2.4
is more similar to TCH/FS and slightly more complicated.
FACCH/F and FACCH/H will be implemented in a follow-up change.
Change-Id: Ib482817b5f6a4e3c7299f6e0b3841143b60fc93d
Related: OS#1572
diff --git a/src/coding/gsm0503_coding.c b/src/coding/gsm0503_coding.c
index f42deb2..b761cd0 100644
--- a/src/coding/gsm0503_coding.c
+++ b/src/coding/gsm0503_coding.c
@@ -3292,4 +3292,301 @@
return 0;
}
+/*
+ * GSM CSD transcoding
+ */
+
+static inline void _tch_csd_burst_map(ubit_t *burst, const ubit_t *iB)
+{
+ for (unsigned int i = 0; i < 57; i++) {
+ burst[i] |= iB[i];
+ burst[59 + i] |= iB[57 + i];
+ }
+
+ burst[57] = 0; /* hl(B) */
+ burst[58] = 0; /* hu(B) */
+}
+
+/*! Perform channel encoding of a TCH/F9.6 channel as per section 3.3.
+ * \param[out] bursts Caller-allocated buffer for symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[in] data Data to be encoded (240 unpacked bits).
+ * \returns 0 in case of success; negative on error. */
+int gsm0503_tch_fr96_encode(ubit_t *bursts, const ubit_t *data)
+{
+ ubit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[4 * 60 + 4];
+
+ /* 3.3.2 Block code: b1(60) + b2(60) + b3(60) + b4(60) + pad(4) */
+ memcpy(&conv[0], &data[0], 4 * 60);
+ memset(&conv[240], 0, 4);
+
+ /* 3.3.3 Convolutional encoder */
+ osmo_conv_encode(&gsm0503_tch_f96, &conv[0], &cB[0]);
+
+ /* 3.3.4 Interleaving */
+ memset(&iB[0], 0, sizeof(iB));
+ gsm0503_tch_f96_interleave(&cB[0], &iB[0]);
+
+ /* 3.3.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++)
+ _tch_csd_burst_map(&bursts[i * 116], &iB[i * 114]);
+
+ return 0;
+}
+
+/*! Perform channel decoding of a TCH/F9.6 channel as per section 3.3.
+ * \param[out] data Caller-allocated buffer for decoded data (240 unpacked bits).
+ * \param[in] bursts Buffer containing the symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[out] n_errors Number of detected bit errors.
+ * \param[out] n_bits_total Total number of bits.
+ * \returns Number of unpacked bits used in the output buffer; negative on error. */
+int gsm0503_tch_fr96_decode(ubit_t *data, const sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[4 * 60 + 4];
+
+ /* 3.3.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++) {
+ memcpy(&iB[i * 114], &bursts[i * 116], 57);
+ memcpy(&iB[i * 114 + 57], &bursts[i * 116 + 59], 57);
+ }
+
+ /* 3.3.4 Interleaving */
+ gsm0503_tch_f96_deinterleave(&cB[0], &iB[0]);
+
+ /* 3.3.3 Convolutional encoder */
+ osmo_conv_decode_ber(&gsm0503_tch_f96, &cB[0], &conv[0], n_errors, n_bits_total);
+
+ /* 3.3.2 Block code: b1(60) + b2(60) + b3(60) + b4(60) + pad(4) */
+ memcpy(&data[0], &conv[0], 4 * 60);
+
+ return 4 * 60;
+}
+
+/*! Perform channel encoding of a TCH/F4.8 channel as per section 3.4.
+ * \param[out] bursts Caller-allocated buffer for symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[in] data Data to be encoded (120 unpacked bits).
+ * \returns 0 in case of success; negative on error */
+int gsm0503_tch_fr48_encode(ubit_t *bursts, const ubit_t *data)
+{
+ ubit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[2 * 60 + 32];
+
+ /* 3.4.2 Block code:
+ *
+ * Sixteen bits equal to 0 are added to the 60 information bits, the result
+ * being a block of 76 bits, {u(0),u(1),...,u(75)}, with:
+ *
+ * u(19k+p) = d(15k+p) for k = 0,1,2,3 and p = 0,1,...,14;
+ * u(19k+p) = 0 for k = 0,1,2,3 and p = 15,16,17,18.
+ *
+ * Two such blocks forming a block of 152 bits: u1 + u2. */
+ for (unsigned int k = 0; k < 2 * 4; k++) {
+ memcpy(&conv[19 * k], &data[15 * k], 15);
+ memset(&conv[19 * k + 15], 0, 4);
+ }
+
+ /* 3.4.3 Convolutional encoder */
+ osmo_conv_encode(&gsm0503_tch_f48, &conv[0], &cB[0]);
+
+ /* 3.4.4 Interleaving: as specified for the TCH/F9.6 in subclause 3.3.4 */
+ memset(&iB[0], 0, sizeof(iB));
+ gsm0503_tch_f96_interleave(&cB[0], &iB[0]);
+
+ /* 3.4.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++)
+ _tch_csd_burst_map(&bursts[i * 116], &iB[i * 114]);
+
+ return 0;
+}
+
+/*! Perform channel decoding of a TCH/F4.8 channel as per section 3.4.
+ * \param[out] data Caller-allocated buffer for decoded data (120 unpacked bits).
+ * \param[in] bursts Buffer containing the symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[out] n_errors Number of detected bit errors.
+ * \param[out] n_bits_total Total number of bits.
+ * \returns Number of unpacked bits used in the output buffer; negative on error. */
+int gsm0503_tch_fr48_decode(ubit_t *data, const sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[2 * 60 + 32];
+
+ /* 3.4.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++) {
+ memcpy(&iB[i * 114], &bursts[i * 116], 57);
+ memcpy(&iB[i * 114 + 57], &bursts[i * 116 + 59], 57);
+ }
+
+ /* 3.4.4 Interleaving: as specified for the TCH/F9.6 in subclause 3.3.4 */
+ gsm0503_tch_f96_deinterleave(&cB[0], &iB[0]);
+
+ /* 3.4.3 Convolutional encoder */
+ osmo_conv_decode_ber(&gsm0503_tch_f48, &cB[0], &conv[0], n_errors, n_bits_total);
+
+ /* 3.4.2 Block code:
+ *
+ * Sixteen bits equal to 0 are added to the 60 information bits, the result
+ * being a block of 76 bits, {u(0),u(1),...,u(75)}, with:
+ *
+ * u(19k+p) = d(15k+p) for k = 0,1,2,3 and p = 0,1,...,14;
+ * u(19k+p) = 0 for k = 0,1,2,3 and p = 15,16,17,18.
+ *
+ * Two such blocks forming a block of 152 bits: u1 + u2. */
+ for (unsigned int k = 0; k < 2 * 4; k++)
+ memcpy(&data[15 * k], &conv[19 * k], 15);
+
+ return 2 * 60;
+}
+
+/*! Perform channel encoding of a TCH/H4.8 channel as per section 3.5.
+ * The algorithm is identical to TCH/F9.6, so it's just a wrapper.
+ * \param[out] bursts Caller-allocated buffer for symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[in] data Data to be encoded (240 unpacked bits).
+ * \returns 0 in case of success; negative on error */
+int gsm0503_tch_hr48_encode(ubit_t *bursts, const ubit_t *data)
+{
+ return gsm0503_tch_fr96_encode(bursts, data);
+}
+
+/*! Perform channel decoding of a TCH/H4.8 channel as per section 3.5.
+ * The algorithm is identical to TCH/F9.6, so it's just a wrapper.
+ * \param[out] data Caller-allocated buffer for decoded data (240 unpacked bits).
+ * \param[in] bursts Buffer containing the symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[out] n_errors Number of detected bit errors.
+ * \param[out] n_bits_total Total number of bits.
+ * \returns Number of unpacked bits used in the output buffer; negative on error. */
+int gsm0503_tch_hr48_decode(ubit_t *data, const sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ return gsm0503_tch_fr96_decode(data, bursts, n_errors, n_bits_total);
+}
+
+/*! Perform channel encoding of a TCH/H2.4 channel as per section 3.7.
+ * \param[out] bursts Caller-allocated buffer for symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[in] data Data to be encoded (144 unpacked bits).
+ * \returns 0 in case of success; negative on error */
+int gsm0503_tch_hr24_encode(ubit_t *bursts, const ubit_t *data)
+{
+ ubit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[2 * 72 + 8];
+
+ /* 3.7.2 Block code: d1(72) + pad(4) + d2(72) + pad(4) */
+ memset(&conv[0], 0, sizeof(conv));
+ memcpy(&conv[0], &data[0], 72);
+ memcpy(&conv[76], &data[72], 72);
+
+ /* 3.7.3 Convolutional encoder: as specified for the TCH/F4.8 in subclause 3.4.3 */
+ osmo_conv_encode(&gsm0503_tch_f48, &conv[0], &cB[0]);
+
+ /* 3.7.4 Interleaving: as specified for the TCH/F9.6 in subclause 3.3.4 */
+ memset(&iB[0], 0, sizeof(iB));
+ gsm0503_tch_f96_interleave(&cB[0], &iB[0]);
+
+ /* 3.7.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++)
+ _tch_csd_burst_map(&bursts[i * 116], &iB[i * 114]);
+
+ return 0;
+}
+
+/*! Perform channel decoding of a TCH/H2.4 channel as per section 3.7.
+ * \param[out] data Caller-allocated buffer for decoded data (144 unpacked bits).
+ * \param[in] bursts Buffer containing the symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[out] n_errors Number of detected bit errors.
+ * \param[out] n_bits_total Total number of bits.
+ * \returns Number of unpacked bits used in the output buffer; negative on error. */
+int gsm0503_tch_hr24_decode(ubit_t *data, const sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[120 + 32];
+
+ /* 3.7.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++) {
+ memcpy(&iB[i * 114], &bursts[i * 116], 57);
+ memcpy(&iB[i * 114 + 57], &bursts[i * 116 + 59], 57);
+ }
+
+ /* 3.7.4 Interleaving: as specified for the TCH/F9.6 in subclause 3.3.4 */
+ gsm0503_tch_f96_deinterleave(&cB[0], &iB[0]);
+
+ /* 3.7.3 Convolutional encoder: as specified for the TCH/F4.8 in subclause 3.4.3 */
+ osmo_conv_decode_ber(&gsm0503_tch_f48, &cB[0], &conv[0], n_errors, n_bits_total);
+
+ /* 3.7.2 Block code: d1(72) + pad(4) + d2(72) + pad(4) */
+ memcpy(&data[0], &conv[0], 72);
+ memcpy(&data[72], &conv[76], 72);
+
+ return 2 * 72;
+}
+
+/*! Perform channel encoding of a TCH/F14.4 channel as per section 3.8.
+ * \param[out] bursts Caller-allocated buffer for symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[in] data Data to be encoded (290 unpacked bits).
+ * \returns 0 in case of success; negative on error */
+int gsm0503_tch_fr144_encode(ubit_t *bursts, const ubit_t *data)
+{
+ ubit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[290 + 4];
+
+ /* 3.8.2 Block code: b(290) + pad(4) */
+ memcpy(&conv[0], &data[0], 290);
+ memset(&conv[290], 0, 4);
+
+ /* 3.8.3 Convolutional encoder */
+ osmo_conv_encode(&gsm0503_tch_f144, &conv[0], &cB[0]);
+
+ /* 3.8.4 Interleaving */
+ memset(&iB[0], 0, sizeof(iB));
+ gsm0503_tch_f96_interleave(&cB[0], &iB[0]);
+
+ /* 3.8.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++)
+ _tch_csd_burst_map(&bursts[i * 116], &iB[i * 114]);
+
+ return 0;
+}
+
+/*! Perform channel decoding of a TCH/14.4 channel as per section 3.8.
+ * \param[out] data Caller-allocated buffer for decoded data (290 unpacked bits).
+ * \param[in] bursts Buffer containing the symbols of 22 bursts,
+ * 22 * 2 * 58 == 2552 bits total.
+ * \param[out] n_errors Number of detected bit errors.
+ * \param[out] n_bits_total Total number of bits.
+ * \returns Number of unpacked bits used in the output buffer; negative on error. */
+int gsm0503_tch_fr144_decode(ubit_t *data, const sbit_t *bursts,
+ int *n_errors, int *n_bits_total)
+{
+ sbit_t iB[22 * 114], cB[4 * 114];
+ ubit_t conv[294];
+
+ /* 3.8.5 Mapping on a burst: as specified for TCH/FS in subclause 3.1.4 */
+ for (unsigned int i = 0; i < 22; i++) {
+ memcpy(&iB[i * 114], &bursts[i * 116], 57);
+ memcpy(&iB[i * 114 + 57], &bursts[i * 116 + 59], 57);
+ }
+
+ /* 3.8.4 Interleaving: as specified for the TCH/F9.6 in subclause 3.3.4 */
+ gsm0503_tch_f96_deinterleave(&cB[0], &iB[0]);
+
+ /* 3.8.3 Convolutional encoder */
+ osmo_conv_decode_ber(&gsm0503_tch_f144, &cB[0], &conv[0], n_errors, n_bits_total);
+
+ /* 3.8.2 Block code: b(290) + pad(4) */
+ memcpy(&data[0], &conv[0], 290);
+
+ return 290;
+}
+
/*! @} */