System and method to provide fairness and service differentation in ad-hoc networks
View Patent ↗A system and method for a media access control (MAC) scheduling algorithm having a distributed, self-coordinating approach to provide use fairness and service differentiation in an ad hoc network by using control RTS/CTS messages carrying node status information. A local scheduling algorithm uses the overheard RTS/CTS information with attributes specifying nodes' status to maximize the awareness of the neighborhood status for a multi-channel system where data and ACK messages are transmitted through different data channels. If the system uses a single channel, the corresponding information may be carried by using DATA or ACK messages. The algorithm measures the offered load, carried load, and backlogged load in the neighborhood to adjust the channel access timer to provide use fairness among different nodes, different links, and different streams. The algorithm can further both calculate the priority level based on the node queue status, and calculate the priority level based on the neighbor status, to break the contention tiers and enable the service differentiation.
1. A method for performing media access control (MAC) scheduling for nodes in an ad-hoc multi-hopping peer-to-peer wireless communication network, the method comprising:
controlling a node attempting a transmission to assess its priority level weight in relation to other nodes in the network based on information included in received request to send (RTS) and clear to send (CTS) messages including those exchanged by the other nodes in the network; and
scheduling the transmission of the node based on the assessed priority level weight.
2. A method as claimed in claim 1 , wherein:
the controlling step further includes assessing priority level weights of neighboring nodes based on received RTS and CTS messages; and
the scheduling step schedules the transmission based on the assess priority level weight of the node and the assessed priority level weights of the neighboring nodes.
3. A method as claimed in claim 1 , wherein:
the information included in the RTS and CTS messages comprises at least one of the following: source and destination MAC addresses, current packet length, data channel rate, selected data channel, tuning factor and weighted queue length computed from the packet priority levels.
4. A method as claimed in claim 1 , wherein:
the information included in the RTS and CTS messages can be carried in DATA and ACK messages respectively if the system uses a single channel and RTS/CTS is not enabled for the transmission.
5. A method as claimed in claim 1 , wherein: the node is a mobile node.
6. A method as claimed in claim 1 , wherein:
the priority level weight is based on an aggregation of weight factors pertaining to the packets in a queue of the node awaiting transmission by the node.
7. A method as claimed in claim 1 , wherein:
the priority level weight is based on information pertaining to at least one other priority level weight of at least one other node.
8. A method for performing media access control (MAC) scheduling for nodes in an ad-hoc multi-hopping peer-to-peer wireless communication network, the method comprising:
controlling a node attempting a transmission to assess its priority level weight, in relation to other nodes in the network, which is based on an aggregation of weight factors pertaining to the packets in a queue of the node awaiting transmission by the node; and
scheduling the transmission of the node based on the assessed priority level weight.
9. A method as claimed in claim 8 , wherein:
the priority level weight is based on information pertaining to at least one other priority level weight of at least one other node.
10. A node, adapted to perform media access control (MAC) scheduling for transmission in an ad-hoc multi-hopping peer-to-peer wireless communication network, the node comprising:
a controller, adapted to assess a priority level weight of the node attempting a transmission, the priority level weight being in relation to other nodes in the network, and being based on at least one of the following: an aggregation of weight factors pertaining to the packets in a queue of the node awaiting transmission by the node, information pertaining to at least one other priority level weight of at least one other node and information included in received request to send (RTS) and clear to send (CTS) messages including those exchanged by the other nodes in the network; and
the controller is further adapted to schedule the transmission by the node based on the assessed priority level weight.
11. A node as claimed in claim 10 , wherein:
the controller is further adapted to assess the priority level weights of neighboring nodes based on received RTS and CTS messages; and
the controller is adapted to schedule the transmission based on the assess priority level weight of the node as adjusted based on the assessed priority level weights of the neighboring nodes.
12. A node as claimed in claim 10 , wherein:
the information included in the RTS and CTS messages comprises at least one of the following: source and destination MAC addresses, current packet length, data channel rate, selected data channel, tuning factor and weighted queue length computed from the packet priority levels.
13. A node as claimed in claim 10 , wherein:
the information included in the RTS and CTS messages can be carried in DATA and ACK messages respectively if the system uses a single channel and RTS/CTS is not enabled for the transmission.
14. A node as claimed in claim 10 , wherein:
the node is a mobile node.
15. A method as claimed in claim 1 , wherein:
the scheduling further includes scheduling the transmission based on a fairness interval relating to timing of use of another node by the node as a next hop for the transmission.
16. A method as claimed in claim 15 , further comprising:
operating a receiving node to include a tuning factor in the CTS message to the transmitting node in response to the RTS message from the node attempting transmission such that the node attempting transmission assesses its fairness interval based on the tuning factor.
17. A method as claimed in claim 8 , wherein:
the scheduling further includes scheduling the transmission based on a fairness interval relating to timing of use of another node by the node as a next hop for the transmission.
18. A method as claimed in claim 17 , wherein:
the fairness interval is further based on a tuning factor included in a CTS message that a receiving node to which the node is attempting transmission sends to and is received by the node.
19. A node as claimed in claim 10 , wherein:
the controller is further adapted to schedule the transmission based on a fairness interval relating to timing of use of another node by the node as a next hop for the transmission.
20. A node as claimed in claim 19 , wherein:
the fairness interval is further based on a tuning factor included in the CTS message that a receiving node to which the node is attempting transmission sends to and is received by the node.