The AT+SQNMONI command can be used to obtain cell coverage information.
AT+SQNMONI=9 returns information on the current serving cell. For example:
+SQNMONI: Dummy Telecom Cc:466 Nc:92 RSRP:-88.20 CINR:-5.90 RSRQ:-17.30 TAC:11801 Id:234 EARFCN:1750 PWR:-63.12 PAGING:128 CID:0x33E2D21 BAND:3 BW:20000
AT+SQNMONI=7 returns information on all available cells.
Please refer to the AT Command Reference Manual for more details on this command