diff --git a/include/osmocom/rspro/BIT_STRING.h b/include/osmocom/rspro/BIT_STRING.h
new file mode 100644
index 0000000..732e878
--- /dev/null
+++ b/include/osmocom/rspro/BIT_STRING.h
@@ -0,0 +1,33 @@
+/*-
+ * Copyright (c) 2003 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_BIT_STRING_H_
+#define	_BIT_STRING_H_
+
+#include <OCTET_STRING.h>	/* Some help from OCTET STRING */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct BIT_STRING_s {
+	uint8_t *buf;	/* BIT STRING body */
+	int size;	/* Size of the above buffer */
+
+	int bits_unused;/* Unused trailing bits in the last octet (0..7) */
+
+	asn_struct_ctx_t _asn_ctx;	/* Parsing across buffer boundaries */
+} BIT_STRING_t;
+
+extern asn_TYPE_descriptor_t asn_DEF_BIT_STRING;
+
+asn_struct_print_f BIT_STRING_print;	/* Human-readable output */
+asn_constr_check_f BIT_STRING_constraint;
+xer_type_encoder_f BIT_STRING_encode_xer;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _BIT_STRING_H_ */