ETSI ES 201 970 (This considers the network equipment interface) Read more about ETSI ES 201 970 (This considers the network equipment interface)
ETSI TS 103 021–3 (ETSI TBR 021 may be an alternative) Read more about ETSI TS 103 021–3 (ETSI TBR 021 may be an alternative)
ETSI TS 103 021–1 (ETSI TBR 021 may be an alternative) Read more about ETSI TS 103 021–1 (ETSI TBR 021 may be an alternative)