diff --git a/include/osmocom/core/gsmtap.h b/include/osmocom/core/gsmtap.h
index 5dc869d..a4e5d42 100644
--- a/include/osmocom/core/gsmtap.h
+++ b/include/osmocom/core/gsmtap.h
@@ -82,6 +82,14 @@
 #define GSMTAP_CHANNEL_PDCH	0x0d
 #define GSMTAP_CHANNEL_PTCCH	0x0e
 #define GSMTAP_CHANNEL_CBCH51	0x0f
+
+/* GPRS Coding Scheme CS1..4 */
+#define GSMTAP_GPRS_CS_BASE	0x20
+#define GSMTAP_GPRS_CS(N)	(GSMTAP_GPRS_CS_BASE + N)
+/* (E) GPRS Coding Scheme MCS0..9 */
+#define GSMTAP_GPRS_MCS_BASE	0x30
+#define GSMTAP_GPRS_MCS(N)	(GSMTAP_GPRS_MCS_BASE + N)
+
 #define GSMTAP_CHANNEL_ACCH	0x80
 
 /* ====== DO NOT MAKE UNAPPROVED MODIFICATIONS HERE ===== */