A bidirectional burst communication method for multicast communications in a carrier sense multiple access, CSMA, network including a first transmitter and a multicast group of n receiving devices (520, 530), where n is greater than or equal to two, the method comprising: the first transmitter winning channel access during a first contention process; the first transmitter making a multicast transmission to the multicast group using a Start of Frame, SOF, delimiter, said SOF including a frame length and identifying information, the frame length giving the duration of a bidirectional burst pseudo contention free period during which the transmitter communicates without contention, and the identifying information indicating one of the n receiving devices (520, 530) which is permitted to send acknowledgement of receipt of a MAC protocol data unit, MPDU, to the first transmitter in the bidirectional burst pseudo contention free period; a receiving device (520, 530), identified by the identifying information in the SOF, transmitting an acknowledgement of receipt of multicast MPDU data to the first transmitter within the duration of the bidirectional burst pseudo contention free period acknowledging receipt of multicast MPDU data; the first transmitter making subsequent multicast transmissions to the multicast group within the time period of the bidirectional burst pseudo contention free period, each one of the subsequent multicast transmissions containing an SOF (410, 540) with identifying information indicating one of each of the n receiving devices (520, 530) yet to transmit an acknowledgement to the first transmitter, each of the subsequent multicast transmissions extending the bidirectional burst pseudo contention free period (440, 440a, 440b) for a duration as indicated by the frame length of the respective SOF (410, 540); and each of the n receiving devices (520, 530) yet to transmit an acknowledgement to the first transmitter transmitting an acknowledgement of receipt of multicast MPDU data, said transmitting an acknowledgement occurring after each of the n receiving devices (520, 530) receives an SOF (410, 540) from the first transmitter transmitter with identifying information indicating a respective one of each of the n receiving devices (520, 530) until the bidirectional burst communication is terminated. the first transmitter winning channel access during a first contention process; the first transmitter making a multicast transmission to the multicast group using a Start of Frame, SOF, delimiter, said SOF including a frame length and identifying information, the frame length giving the duration of a bidirectional burst pseudo contention free period during which the transmitter communicates without contention, and the identifying information indicating one of the n receiving devices (520, 530) which is permitted to send acknowledgement of receipt of a MAC protocol data unit, MPDU, to the first transmitter in the bidirectional burst pseudo contention free period; a receiving device (520, 530), identified by the identifying information in the SOF, transmitting an acknowledgement of receipt of multicast MPDU data to the first transmitter within the duration of the bidirectional burst pseudo contention free period acknowledging receipt of multicast MPDU data; the first transmitter making subsequent multicast transmissions to the multicast group within the time period of the bidirectional burst pseudo contention free period, each one of the subsequent multicast transmissions containing an SOF (410, 540) with identifying information indicating one of each of the n receiving devices (520, 530) yet to transmit an acknowledgement to the first transmitter, each of the subsequent multicast transmissions extending the bidirectional burst pseudo contention free period (440, 440a, 440b) for a duration as indicated by the frame length of the respective SOF (410, 540); and each of the n receiving devices (520, 530) yet to transmit an acknowledgement to the first transmitter transmitting an acknowledgement of receipt of multicast MPDU data, said transmitting an acknowledgement occurring after each of the n receiving devices (520, 530) receives an SOF (410, 540) from the first transmitter transmitter with identifying information indicating a respective one of each of the n receiving devices (520, 530) until the bidirectional burst communication is terminated.