A radio unit (100, 300, 500) for un-synchronized Time Division Duplex, TDD, multi-band operation in a wireless communication system, the radio unit comprising: a transmitting power amplifier for multi-band operation; one or more receiving amplifiers (121, 122) for multi-band operation; an antenna element; two or more switch networks (140, 310, 320) coupled in parallel between the transmitting power amplifier and the antenna element and comprising a first filter (FU 1a, FU 2a), a circulator (312, 322) and a second filter (FU 1b, FU 2b); wherein each of the two or more switch networks (140, 310, 320) comprises a shunt switch (K1, K3) coupled between an output of the first filter (FU 1a, FU 2a) and a signal ground; each of the two or more switch networks (140, 310, 320) is configured to operate at a certain frequency band in transmitting or receiving mode and is controlled separately by a switching control unit based on un-synchronized TDD time slots configured according to user data traffic scheduling requirements such that when operating in transmitting mode, the switch network (140, 150, 310, 320) is controlled to couple the transmitting power amplifier via the first filter (FU 1a, FU 2a) the circulator (312, 322) and the second filter (FU 1b, FU 2b), to the antenna element and dis-couple one of the one or more receiving amplifiers (121, 122) from the antenna element; and when operating in receiving mode, the switch network (140, 310, 320) is controlled to couple one of the one or more receiving amplifiers (121, 122) to the antenna element via the second filter (FU 1b, FU 2b) and the circulator (312, 322), and dis-couple the transmitting power amplifier from the antenna element by coupling said at least one shunt switches (K1, K3) to the signal ground. a transmitting power amplifier for multi-band operation; one or more receiving amplifiers (121, 122) for multi-band operation; an antenna element; two or more switch networks (140, 310, 320) coupled in parallel between the transmitting power amplifier and the antenna element and comprising a first filter (FU 1a, FU 2a), a circulator (312, 322) and a second filter (FU 1b, FU 2b); wherein each of the two or more switch networks (140, 310, 320) comprises a shunt switch (K1, K3) coupled between an output of the first filter (FU 1a, FU 2a) and a signal ground; each of the two or more switch networks (140, 310, 320) is configured to operate at a certain frequency band in transmitting or receiving mode and is controlled separately by a switching control unit based on un-synchronized TDD time slots configured according to user data traffic scheduling requirements such that when operating in transmitting mode, the switch network (140, 150, 310, 320) is controlled to couple the transmitting power amplifier via the first filter (FU 1a, FU 2a) the circulator (312, 322) and the second filter (FU 1b, FU 2b), to the antenna element and dis-couple one of the one or more receiving amplifiers (121, 122) from the antenna element; and when operating in receiving mode, the switch network (140, 310, 320) is controlled to couple one of the one or more receiving amplifiers (121, 122) to the antenna element via the second filter (FU 1b, FU 2b) and the circulator (312, 322), and dis-couple the transmitting power amplifier from the antenna element by coupling said at least one shunt switches (K1, K3) to the signal ground.