통신이 · 통신을
communication(s), telecommunications
Example
산속에서는 휴대폰 통신이 잘 안 돼요.
Cell phone reception is poor in the mountains.
Word parts
통 go through+신 message
Literally 'messages going through.'
Good to know
통신사 is your mobile carrier, and 통신비 is your phone bill.
Related words