Distributed scheduling in wireless networks with service differentiation
View Patent ↗An apparatus includes a first node configured to transmit both data frames and requests for channel reservations to a local contention neighborhood of a network. The first node is configured to compete with other nodes of the neighborhood for reservations to the channel. The first node is configured to dynamically update a stored value of an access priority for the first node and to transmit said requests with a rate that depends on the stored value.
1. An apparatus, comprising:
a first node configured to transmit both data frames and requests for channel reservations to a local contention neighborhood of a network, the first node being configured to compete with other nodes of the neighborhood for reservations to the channel; and
wherein the first node is configured to:
dynamically update an access contention level from monitoring collisions between requests or grants of channel reservations from the other nodes during contention time slots;
dynamically update a stored value of an access priority for the first node that corresponds to the access contention level; and
transmit the requests with a rate responsive to the stored value of the access priority.
2. The apparatus of claim 1 , wherein the first node is configured to transmit said requests with a rate that decreases as the access contention level in the local contention neighborhood increases.
3. The apparatus of claim 2 , wherein the first node is configured to decrease a stored value of the access contention level by a preselected percentage in response to sensing a successful transmission of one of the requests by one of the nodes of the neighborhood.
4. The apparatus of claim 1 , wherein the first node is configured to dynamically update a stored value of an access threshold and to transmit the requests in response to the stored value of the access priority being over a threshold fixed by a stored value of the access threshold.
5. The apparatus of claim 4 , wherein the first node is configured to update the stored value of the access threshold in response to sensing a grant of a channel reservation to another node of the neighborhood.
6. The apparatus of claim 4 , wherein the first node is configured to perform throughput sharing with other nodes of the local contention neighborhood.
7. The apparatus of claim 1 , wherein said contention time slots occur during periods for channel contention (PCC), said data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.
8. A method, comprising:
storing a value of an access priority for a first node of a local contention neighborhood, the neighborhood having a plurality of other nodes that compete with the first node for access to a channel, wherein the access priority corresponds to a contention level of the neighborhood, the contention level dynamically updated from a monitoring of collisions between requests or grants of channel reservations from the plurality of other nodes during contention time slots;
transmitting a plurality of requests for reservations of the channel from the first node, the rate of the transmitting the requests depending on the stored value of the access priority; and
wherein the storing includes updating the stored value of the access priority between transmitting ones of the requests.
9. The method of claim 8 , further comprising:
updating the stored access priority in a manner that causes throughput sharing between the first node and other nodes of the local contention neighborhood.
10. The method of claim 8 , further comprising:
updating a stored access threshold between ones of the steps of transmitting requests; and
wherein each step of transmitting is responsive to the stored access priority being over a threshold fixed by the stored access threshold.
11. The method of claim 10 , further comprising:
updating the stored access threshold responsive to sensing a grant of a reservation of the channel to one of the other nodes of the neighborhood.
12. The method of claim 8 , wherein said contention time slots occur during periods for channel contention (PCC), data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.
13. A method, comprising:
monitoring for requests of channel reservation or grants of channel reservations to nodes of a local contention neighborhood and for collisions between the requests or grants, the monitoring being performed by one of the nodes; and
updating a value of an access threshold stored in the one of the nodes in response to the monitoring sensing a request or grant of a channel reservation to one of the other nodes, the updating replacing the stored value of the access threshold with a value obtained from the sensed request or grant; and
transmitting a request for a channel reservation from the one of the nodes in response to an access priority of the one of the nodes passing a threshold associated with the stored value of the access threshold, wherein the access priority corresponds to a contention level of the neighborhood, the contention level dynamically updated from the monitoring of collisions during contention time slots.
14. The method of claim 13 , wherein said contention time slots occur during periods for channel contention (PCC), data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.
15. A system for distributed scheduling, comprising:
a plurality of nodes belonging to a local contention neighborhood, each node being configured to transmit requests for channel reservations and data frames to other nodes of the neighborhood and being able to compete with the other nodes for access to the channel; and
wherein each node is configured to:
store a value for an access contention level in the neighborhood, the stored value dynamically updated from a monitoring of collisions between the requests or grants of channel reservations from the plurality of nodes during contention time slots;
transmit the requests at a rate that decreases as the stored value increases; and
decrease the stored value in a manner proportional to the stored value in response to sensing a successful transmission of a request for a channel reservation between two of the nodes in the neighborhood.
16. The system of claim 15 , wherein each node is configured to increase the stored access contention value in a manner proportional to the stored access contention value in response to sensing a collision of two requests for channel reservations in the neighborhood.
17. The system of claim 15 , wherein the each node having a probability for requesting a channel reservation that depends on the stored value.
18. The system of claim 17 , wherein the each node is configured to store a value of an access threshold and to request a channel reservation in response to the access priority associated with the same node being over a threshold defined by the value of the access threshold stored by the same node.
19. The system of claim 15 , wherein said contention time slots occur during periods for channel contention (PCC), said data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.
20. A method for operating a node in a wireless network, comprising:
receiving a request for a channel reservation from a first node of a local contention neighborhood of the network, wherein the request includes an access priority corresponding to a contention level of the neighborhood, the contention level dynamically updated from a monitoring of collisions between requests or grants of channel reservations from nodes in the neighborhood during a contention time; and
transmitting a grant of the channel reservation to the local contention neighborhood in response to the deciding to grant the request from the first node; and
wherein the transmitted grant includes a new value of a channel access threshold for the neighborhood, nodes of the neighborhood having access priorities below a threshold fixed by the channel access threshold being unable to transmit a request for a channel reservation.
21. The method of claim 20 , wherein the transmitting includes determining the new value of the channel access threshold from a value of an access priority in the request from the first node.
22. The method of claim 20 , wherein said contention time slots occur during periods for channel contention (PCC), data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.
23. A system, comprising:
plurality of nodes capable of transmitting data frames in a local contention neighborhood of a wireless network, the nodes being configured to compete with each other for access to a shared channel of the wireless network; and
wherein each node is configured to store and dynamically update an associated access priority variable, the access priority variable corresponding to a contention level of the neighborhood which is dynamically updated from a monitoring of collisions between requests or grants of channel reservations from the plurality of nodes during contention time slots, a probability of one of the nodes of requesting access to the channel depending on a value of the access priority variable stored in the one of the nodes.
24. The system of claim 23 , wherein each node is configured to monitor for requests of channel accesses or grants of channel accesses to the other nodes in the local contention neighborhood and to update its stored value of the access threshold variable responsive to sensing one of the requests or grants.
25. The system of claim 23 , wherein each node is configured to store and dynamically update a value of an access threshold for the neighborhood, one of the nodes being configured to request access to the channel in response to the value of access priority stored by the one of the nodes being over a threshold defined by a value of the access threshold variable stored by the same node.
26. The system of claim 23 , wherein said contention time slots occur during periods for channel contention (PCC), said data frames are transmitted during separate periods for transmission of data frames (PTDF), and wherein said PCC are interleaved with said PTDF.