Method for sending and receiving data in a wireless machine to machine network, the wireless machine to machine communication network comprising at least one gateway and a plurality of nodes sharing at least a common transmission frequency, the communications between the at least one gateway and the plurality of nodes is organized in frames, repeated along time, each frame comprising a plurality of time slots of a fixed length, the time slots including uplink time slots and downlink time slots, wherein within each frame, each time slot is transmitted over a different frequency and the method comprises: - sending feedback information from the gateway to the nodes, during a first subperiod of the uplink time slots, indicating if collisions occurred during the preceding time slot; - sending data transmission requests from the nodes to the gateway during a second subperiod of the uplink time slots; - sending data transmissions from the nodes to the gateway during a third subperiod of the uplink time slots; - determining at the gateway if a collision occurs during the second subperiod, the collision occurring when multiple data transmission requests simultaneously to the gateway by different nodes; - if the data transmission requests are received at the gateway without collisions, positioning the nodes sending the data transmission requests in a first queue, the first queue defining the position in which a queued node is allowed to send a data transmission; - if the data transmission requests result in collisions, positioning the nodes sending data transmission requests in a second queue, the second queue defining the position in which a queued node is allowed to send a data transmission request; the method further comprising, the gateway transmitting, preceding each frame, a control signal including information about which time slots of the frame are reserved for downlink data transmissions, and which time slots are reserved for uplink data transmissions, including also synchronization information used by the plurality of nodes for synchronizing and including also information about the sequence of frequency over which the time slots of the frame are transmitted. - sending feedback information from the gateway to the nodes, during a first subperiod of the uplink time slots, indicating if collisions occurred during the preceding time slot; - sending data transmission requests from the nodes to the gateway during a second subperiod of the uplink time slots; - sending data transmissions from the nodes to the gateway during a third subperiod of the uplink time slots; - determining at the gateway if a collision occurs during the second subperiod, the collision occurring when multiple data transmission requests simultaneously to the gateway by different nodes; - if the data transmission requests are received at the gateway without collisions, positioning the nodes sending the data transmission requests in a first queue, the first queue defining the position in which a queued node is allowed to send a data transmission; - if the data transmission requests result in collisions, positioning the nodes sending data transmission requests in a second queue, the second queue defining the position in which a queued node is allowed to send a data transmission request;