diff --git a/lib/decoding/osmocom/coding/gsm0503_mapping.h b/lib/decoding/osmocom/coding/gsm0503_mapping.h
new file mode 100644
index 0000000..4c6550a
--- /dev/null
+++ b/lib/decoding/osmocom/coding/gsm0503_mapping.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <osmocom/core/bits.h>
+
+void gsm0503_xcch_burst_unmap(sbit_t *iB, const sbit_t *eB,
+	sbit_t *hl, sbit_t *hn);
+void gsm0503_xcch_burst_map(ubit_t *iB, ubit_t *eB, const ubit_t *hl,
+	const ubit_t *hn);
+
+void gsm0503_tch_burst_unmap(sbit_t *iB, sbit_t *eB, sbit_t *h, int odd);
+void gsm0503_tch_burst_map(ubit_t *iB, ubit_t *eB, const ubit_t *h, int odd);
+
+void gsm0503_mcs5_ul_burst_map(const ubit_t *di, ubit_t *eB,
+	const ubit_t *hi, int B);
+void gsm0503_mcs5_ul_burst_unmap(sbit_t *di, const sbit_t *eB,
+	sbit_t *hi, int B);
+
+void gsm0503_mcs7_ul_burst_map(const ubit_t *di, ubit_t *eB,
+	const ubit_t *hi, int B);
+void gsm0503_mcs7_ul_burst_unmap(sbit_t *di, const sbit_t *eB,
+	sbit_t *hi, int B);
+
+void gsm0503_mcs5_dl_burst_map(const ubit_t *di, ubit_t *eB,
+	const ubit_t *hi, const ubit_t *up, int B);
+void gsm0503_mcs5_dl_burst_unmap(sbit_t *di, const sbit_t *eB,
+	sbit_t *hi, sbit_t *up, int B);
+
+void gsm0503_mcs7_dl_burst_map(const ubit_t *di, ubit_t *eB,
+	const ubit_t *hi, const ubit_t *up, int B);
+void gsm0503_mcs7_dl_burst_unmap(sbit_t *di, const sbit_t *eB,
+	sbit_t *hi, sbit_t *up, int B);
+
+void gsm0503_mcs5_burst_swap(sbit_t *eB);