A radio frequency, RF, system, comprising an RF transceiver, an RF processing circuit, a transfer switch module, a first antenna, a second antenna, a third antenna, and a fourth antenna; the RF transceiver being coupled with the RF processing circuit; the first antenna and the second antenna each having a higher antenna efficiency than the third antenna and the fourth antenna; the RF processing circuit comprising a first transmit, TX, module, a second TX module, a first receive, RX, module, a second RX module, a first duplexer, a second duplexer, a first multiplexing switch, and a first filtering module; the first TX module being coupled with the first antenna via the first duplexer and the transfer switch module, and the first TX module being coupled with the first antenna via the first multiplexing switch, the second duplexer, and the transfer switch module; the second TX module being coupled with the second antenna via the transfer switch module; the first RX module having a first RX port that is coupled with the first antenna via the first duplexer and the transfer switch module; the first RX module having a second RX port that is coupled with the first antenna via the second duplexer, the first multiplexing switch, the second TX module, and the transfer switch module and coupled with the second antenna via the second duplexer and the transfer switch module; and the first RX module having a third RX port that is coupled with the second antenna via the second TX module and the transfer switch module; the second RX module having a first RX port that is coupled with the fourth antenna via the first filtering module; and the second RX module having a second RX port that is coupled with the third antenna via the transfer switch module or a selective filtering module; and when the RF system works in a non-standalone, NSA, mode, the first antenna being configured for TX of a first low band, LB, and primary receive, PRX, of the first LB, the second antenna being configured for TX of a second LB and PRX of the second LB, the third antenna being configured for diversity receive, DRX, of the second LB, the fourth antenna being configured for DRX of the first LB, and the first filtering module being configured to filter a band other than the first LB. the RF transceiver being coupled with the RF processing circuit; the first antenna and the second antenna each having a higher antenna efficiency than the third antenna and the fourth antenna; the RF processing circuit comprising a first transmit, TX, module, a second TX module, a first receive, RX, module, a second RX module, a first duplexer, a second duplexer, a first multiplexing switch, and a first filtering module; the first TX module being coupled with the first antenna via the first duplexer and the transfer switch module, and the first TX module being coupled with the first antenna via the first multiplexing switch, the second duplexer, and the transfer switch module; the second TX module being coupled with the second antenna via the transfer switch module; the first RX module having a first RX port that is coupled with the first antenna via the first duplexer and the transfer switch module; the first RX module having a second RX port that is coupled with the first antenna via the second duplexer, the first multiplexing switch, the second TX module, and the transfer switch module and coupled with the second antenna via the second duplexer and the transfer switch module; and the first RX module having a third RX port that is coupled with the second antenna via the second TX module and the transfer switch module; the second RX module having a first RX port that is coupled with the fourth antenna via the first filtering module; and the second RX module having a second RX port that is coupled with the third antenna via the transfer switch module or a selective filtering module; and when the RF system works in a non-standalone, NSA, mode, the first antenna being configured for TX of a first low band, LB, and primary receive, PRX, of the first LB, the second antenna being configured for TX of a second LB and PRX of the second LB, the third antenna being configured for diversity receive, DRX, of the second LB, the fourth antenna being configured for DRX of the first LB, and the first filtering module being configured to filter a band other than the first LB.