Method for regulating data transmission over a communication channel, corresponding device and computer program product
Transmission of data frames over a channel in a communications network takes place on a slotted time base. A method comprises an evaluation, by at least one node of the network having a frame available for transmission, of whether the channel is available for transmission. If the channel is available for transmission, the available frame is transmitted over the channel in a subsequent slot of the slotted time base. If the channel is not available for transmission, owing to a frame (having a certain temporal length) being transmitted over the channel at a certain time, the slotted time base of the node is resynchronized as a function of the frame being transmitted. The resynchronization includes identifying, as a function of the certain temporal length, an interval of delay to evaluate again at a future time whether the channel is available for transmission.
1. A method of regulating transmission of data frames over a channel in a communications network, wherein the transmission is on a slotted time base and the method includes:
evaluating, by at least one node in the network having a frame available for transmission, whether the channel is available for transmission based upon an initially synchronized slotted time base; and
if the evaluation indicates that the channel is available for transmission, transmitting the available frame on the channel; and
if the evaluation indicates that the channel is unavailable for transmission due to a frame being transmitted over the channel at a certain time and having a certain time length, re-synchronizing the slotted time base of the at least one node in the network as a function of the frame being transmitted by identifying as a function of the certain time length a delay interval to evaluate again at a subsequent time whether the channel is available for transmission of the available frame.
2. The method of claim 1 , wherein evaluating includes at least two subsequent checks of whether the channel is available for transmission, the at least two subsequent checks being separated by a sensing interval.
3. The method of claim 1 , wherein the evaluating includes checking whether the channel is available for transmission over a plurality of slots of the slotted time base.
4. The method of claim 3 , wherein the plurality of slots consists of two time slots.
5. The method of claim 1 , wherein the certain time length is the time length of the payload of the frame being transmitted over the channel.
6. The method of claim 1 , wherein transmitting the available frame on the channel is performed without re-synchronizing the slotted time base of the node that transmits the available frame.
7. The method of claim 1 , wherein the nodes in the network different from the node that transmits the available frame over the channel resynchronize their slotted time base as a function of the certain time length and the certain time.
8. The method of claim 1 , wherein evaluating whether the channel is available for transmission is performed before the expiry of a certain slot of the slotted time base, and wherein, if the evaluation indicates that the channel is available for transmission, the available frame is transmitted in the slot of the slotted time immediately following the certain slot.
9. The method of claim 1 , wherein the value of the delay interval for evaluating again whether the channel is available for transmission at a subsequent time is increased as a function of the number of times in which the channel is ascertained to be unavailable for transmission.
10. The method of claim 1 , further comprising returning a message indicative of transmission failed if the number of times in which the channel is ascertained to be unavailable for transmission equals an upper limit value.
11. A device for transmitting data frames over a channel in a communications network wherein the transmission is on a slotted time base, the device comprising:
a processor and a memory coupled thereto configured to
have a frame available for transmission based upon an initially synchronized slotted time base,
evaluate whether the channel is available for transmission,
if the evaluation indicates that the channel is available for transmission, transmit the available frame on the channel, and
if the evaluation indicates that the channel is unavailable for transmission due to a frame being transmitted over the channel at a certain time and having a certain time length, re-synchronize the slotted time base as a function of the frame being transmitted by identifying as a function of the certain time length a delay interval to evaluate again at a subsequent time whether the channel is available for transmission of the available frame.
12. The device of claim 11 , wherein evaluating whether the channel is available for transmission includes at least two subsequent checks of whether the channel is available for transmission, the at least two subsequent checks being separated by a sensing interval.
13. The device of claim 11 , wherein the evaluating whether the channel is available for transmission includes checking whether the channel is available for transmission over a plurality of slots of the slotted time base.
14. The device of claim 11 , wherein the certain time length is the time length of the payload of the frame being transmitted over the channel.
15. The device of claim 11 , wherein transmitting the available frame on the channel is performed without re-synchronizing the slotted time base of the device.
16. The device of claim 11 , wherein evaluating whether the channel is available for transmission is performed before the expiry of a certain slot of the slotted time base, and wherein, if the evaluation indicates that the channel is available for transmission, the available frame is transmitted in the slot of the slotted time immediately following the certain slot.
17. A non-transitory computer-readable medium encoded with executable instructions that, when executed by a processing circuitry, cause one or more processors to:
evaluate whether the channel is available for transmission based upon an initially synchronized slotted time base;
if the evaluation indicates that the channel is available for transmission, transmit the available frame on the channel; and
if the evaluation indicates that the channel is unavailable for transmission due to a frame being transmitted over the channel at a certain time and having a certain time length, re-synchronize the slotted time base as a function of the frame being transmitted by identifying as a function of the certain time length a delay interval to evaluate again at a subsequent time whether the channel is available for transmission of the available frame.
18. The non-transitory computer-readable medium of claim 17 , wherein evaluating whether the channel is available for transmission includes at least two subsequent checks of whether the channel is available for transmission, the at least two subsequent checks being separated by a sensing interval.
19. The non-transitory computer-readable medium of claim 17 , wherein the evaluating whether the channel is available for transmission includes checking whether the channel is available for transmission over a plurality of slots of the slotted time base.
20. The non-transitory computer-readable medium of claim 17 , wherein the certain time length is the time length of the payload of the frame being transmitted over the channel.