User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail

Filing statistics

CPC H04L 51/00 belongs to the parent subclass H04L, which recorded 1,567,994 patent applications worldwide between 2013 and 2023. Annual filings grew from 97,627 in 2013 to 139,810 in 2023 (+43%), peaking at 168,964 applications in 2020. The most active applicants in class H04 are HUAWEI TECHNOLOGIES COMPANY (101,476 applications), QUALCOMM (101,139 applications) and SAMSUNG ELECTRONICS COMPANY (96,655 applications).

Source: EPO PATSTAT, worldwide filings

10 direct subcodes

Child Classifications

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H04L 51/02 using automatic reactions or user delegation, e.g. automatic replies or chatbot-generated messages
H04L 51/04 Real-time or near real-time messaging, e.g. instant messaging [IM]
H04L 51/06 Message adaptation to terminal or network requirements
H04L 51/07 characterised by the inclusion of specific contents
H04L 51/21 Monitoring or handling of messages
H04L 51/42 Mailbox-related aspects, e.g. synchronisation of mailboxes
H04L 51/48 Message addressing, e.g. address format or anonymous messages, aliases
H04L 51/52 for supporting social networking services
H04L 51/56 Unified messaging, e.g. interactions between e-mail, instant messaging or converged IP messaging [CPM]
H04L 51/58 Message adaptation for wireless communication

Top Applicants

Top 10 applicants by patent filingsfor class H04, 2013–2023, worldwide · Source: EPO PATSTAT

HUAWEI TECHNOLOGIES COMPANY CN 101,476
QUALCOMM US 101,139
SAMSUNG ELECTRONICS COMPANY KR 96,655
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) SE 57,744
LG ELECTRONICS KR 55,253
HUAWEI TECHNOLOGIES COMPANY 54,181
SONY CORPORATION JP 35,309
ZTE CORPORATION CN 32,950
INTEL CORPORATION US 27,533
GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORPORATION CN 27,498