Method and apparatus for sending and receiving data in a machine to machine wireless network

A gateway (2) for a wireless machine to machine communication network, the wireless machine to machine communication network comprising a plurality of nodes (4) sharing at least a common transmission frequency with the gateway (2), the communications between the gateway (2) and the plurality of nodes (4) is organized in frames (18), repeated along time, each frame comprising a plurality of time slots (19) of a fixed length, the time slots (19) comprising uplink time slots (19) and downlink time slots (19), characterized in that within each frame (18) each time slot (19) is transmitted over a different frequency and in that the gateway (2) comprises communication means (12) and computing means (11) configured to:

• send feedback information (32) to the nodes (4), during a first subperiod (20) of the uplink time slots (19), the feedback information (32) indicating if a collision occurred during the second subperiod (21) of the preceding time slot (19);
• said information determining if the nodes (4) sending data transmission requests (25) are to be queued either in a first queue, which defines the position in which a queued node (4) is allowed to send a data transmission (26) if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has been received in the gateway without collision, or in a second queue which defines the position in which a queued node (4) is allowed to send a data transmission request (25) if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has resulted in collision;
• receive data transmission requests (33) from the nodes (4) to the gateway (4) during the second subperiod (21) of the uplink time slots (19);
• receive data transmissions (34) from the nodes (4) during a third subperiod (22) of the uplink time slots (19);
• determine if a collision occurs during each mini-slot of the second subperiod (21), the collision occurring when multiple data transmission requests (25) are sent to the gateway simultaneously by different nodes;
• transmitting, preceding each frame, a control signal (17) 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.

A node (4) for a wireless machine to machine communication network, the wireless machine to machine communication network comprising a plurality of nodes (4) sharing at least a common transmission frequency with a gateway (2), the communications between the gateway (2) and the plurality of nodes (4) is organized in frames (18), repeated along time, each frame comprising a plurality of time slots (19) of a fixed length, the time slots (19) comprising uplink time slots (19) and downlink time slots (19), characterized in that within each frame (18) each time slot (19) is transmitted over a different frequency and in that the node (4) comprises communication means (12) and computing means (11) configured to:

• receive feedback information (41) from the gateway (2), during a first subperiod (20) of the uplink time slots (19), the feedback information (23) stating if a collision caused by multiple data transmission requests (25) being sent to the gateway simultaneously by different nodes during the second subperiod of the preceding uplink time slot (21) occurs;
• according to the received feedback information (23), determining that the node (4) is to be queued either in a first queue which defines the position in which a queued node (4) is allowed to send a data transmission (26), if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has been received in the gateway without collision, or determining that the node (4) is to be queued in a second queue which defines the position in which a queued node (4) is allowed to send a data transmission request (25), if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has resulted in collision;
• send data transmission requests (42) to the gateway (2) during a second subperiod (21) of the uplink time slots (19), and to send data transmissions (26) to the gateway (2) during a third subperiod (22) of the uplink time slots (19);
• receive from the gateway, preceding each frame, a control signal (17) 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.

A machine to machine wireless communication network comprising at least one gateway (2) and a plurality of nodes (4) sharing at least a common transmission frequency, the communications between the at least one gateway (2) and the plurality of nodes (4) is organized in frames (18), repeated along time, each frame comprising a plurality of time slots (19) of a fixed length, the time slots (19) comprising uplink time slots (19) and downlink time slots (19), wherein within each frame (18) each time slot (19) is transmitted over a different frequency and in that and wherein the nodes (4) are configured to:

• send data transmission requests (25) during a second subperiod (21) of the uplink time slots (19);
• send data transmissions (26) during a third subperiod (22) of the uplink time slots (19);
• characterized in that:
• at least one gateway (2) is configured to determine if a collision occurs during the second subperiod (21), the collision occurring when multiple data transmission requests (25) are sent to the gateway (2) simultaneously by different nodes;
• and to send feedback information (23) to the nodes (4), during a first subperiod (20) of the subsequent uplink time slots (19), indicating if collisions occur;
• the nodes (4) are further configured to, according to the feedback information (23), determine if the node (4) is to be queued either in a first queue which defines the position in which a queued node (4) is allowed to send a data transmission (26), if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has been received in the gateway without collision, or in a second queue which defines the position in which a queued node (4) is allowed to send a data transmission request (25), if the node has sent a data transmission request in the second subperiod of the preceding uplink time slot (21) and said data transmission request has resulted in collision;
• the gateway being further configured for, preceding each frame, transmitting a control signal (17) 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.