Method and system for distributed admission control in mobile ad hoc networks (MANETs)

1. A method for distributed admission control and quality of service (QoS) in a wireless multi-hop network, the wireless multi-hop network comprising a plurality of nodes including a source node, a destination node, and a plurality of intermediate nodes, the method comprising:

at at least one of the plurality of intermediate nodes along a route between the source node and the destination node:

receiving a new communication stream including a QoS requirement of the new communication stream from the source node destined for the destination node,

temporarily admitting the new communication stream during a temporary admission period,

determining, during the temporary admission period, whether the at least one of the plurality of intermediate nodes can support the QoS requirement of the new communication stream;

transmitting, when the at least one of the plurality of intermediate nodes determines that it is unable to support the QoS requirement of the new communication stream, an indicator which indicates one or more suggested QoS requirements that the at least one of the plurality of intermediate nodes could provide to the source node;

receiving, at one or more of the plurality of nodes, the indicator including the one or more suggested QoS requirements; and

forwarding the indicator from at least one of the one or more of the plurality of nodes towards the source node;

stopping, at the source node upon receiving the indicator, generation of packets of the new communication stream; and

determining, at the source node upon receiving the indicator, whether using the suggested one or more of the QoS requirements of the new communication stream will increase chances of admission of the new communication stream along the route.

2. The method as claimed in claim 1 , further comprising at the the at least one of the plurality of intermediate nodes:

permitting transmission after the temporary admission period of the new communication stream by the source node when the at least one of the plurality of intermediate nodes determines that it can support the QoS requirement of the new communication stream.

3. The method as claimed in claim 1 , wherein the operation of determining, at the at least one of the plurality of intermediate nodes during the temporary admission period, whether the at least one of the plurality of intermediate nodes can support the QoS requirement of the new communication stream comprises:

determining, at the at least one of the plurality of intermediate nodes during the temporary admission period, whether that at least one of the plurality of intermediate nodes is able to support each of its currently supported communication streams according to QoS requirements associated with each of the currently supported communication streams; and

when the at least one of the plurality of intermediate nodes is unable to support one or more of its currently supported communication streams according to the QoS requirements associated with the currently supported communication streams, determining whether a degradation of at least one of the currently supported communication streams by that at least one of the plurality of intermediate nodes is caused by the new communication stream.

4. The method as claimed in claim 3 , further comprising at the the at least one of the plurality of intermediate nodes:

determining, upon receiving the new communication stream, whether the new communication stream has at least one metric higher than a metric of any of the currently supported communication streams of the at least one of the plurality of intermediate nodes; and

admitting the new communication stream at the at least one of the plurality of intermediate nodes when the at least one of the plurality of intermediate nodes determines that the new communication stream has at least one metric higher than a metric of any of the currently supported communication streams of the at least one of the plurality of intermediate nodes such that continued transmission of the new communication stream from the source node is permitted by the at least one of the plurality of intermediate nodes.

5. The method as claimed in claim 1 , further comprising at the at least one of the plurality of intermediate nodes:

determining whether a fraction of time that a channel is busy is below a threshold; and

suppressing transmission of the indicator when the fraction of time that the channel is busy is below the threshold.

6. The method as claimed in claim 1 , further comprising at the at least one of the plurality of intermediate nodes:

determining whether packet transmission rates of neighbor nodes have not increased by more than a particular percentage; and

suppressing transmission of the indicator when the packet transmission rates of the neighbor nodes have not increased by more than the particular percentage.

7. The method as claimed in claim 1 , further comprising in response to receiving the indicator at the source node, operating the source node to:

determining whether one or more alternative routes to the destination node exist;

selecting one of the one or more alternative routes to the destination node using a selection criteria, wherein the selection criteria are designed to decrease a probability of selection of routes which: include one or more relay nodes that have received an indicator from a peripheral node, or include peripheral nodes that have generated an indicator; and

transmitting a re-route request message to other nodes if no alternative routes to the destination node exist, wherein the re-route request message requests that one or more nodes change one or more routes of their currently supported communication streams to change topology such that new communication stream can be admitted without degrading QoS requirements of their currently supported communication streams.

8. The method as claimed in claim 1 , further comprising:

receiving, at one or more of the plurality of nodes, the indicator; and

stopping, at the one of the one or more of the plurality of nodes which receives the indicator, processing of packets of the new communication stream.

9. The method as claimed in claim 1 , wherein the plurality of nodes further include: one or more relay nodes along the route between the source node and the destination node, and wherein the new communication stream is communicated towards the destination node by the one or more relay nodes, and further comprising:

receiving, at the one or more relay nodes, the indicator; and

stopping, at the one or more relay nodes which receive the indicator, relaying of packets of the new communication stream.

10. The method as claimed in claim 1 , wherein the new communication stream comprises: one or more dummy packets which are transmitted using a same packet size and a same packet inter-arrival time as regular packets of the new communication stream during the temporary admission period.

11. The method as claimed in claim 1 , wherein transmitting an indicator further, comprises:

transmitting a unicast QoS Infringement Alert (QIA) message to a neighbor node which has a highest increase of packet transmission rate during a measurement period.

12. The method as claimed in claim 1 , further comprising:

communicating two new communication streams to the at least one of the plurality of intermediate nodes;

assigning a priority to each of the two new communication streams based on at least one metric associated with each of the two new communication streams;

receiving, at the at least one of the plurality of intermediate nodes, the indicator; and

stopping, at the node upon receiving the indicator, processing of packet associated with the new communication stream having a lower priority.

13. A wireless multi-hop network for providing admission control and quality of service (QoS), the wireless multi-hop network comprising:

a destination node;

a source node; and

at least one intermediate node along a route between the source node and the destination node, the at least one intermediate node operating to: receive a new communication stream including a QoS requirement of the new communication stream from the source node and destined for the destination node,

temporarily admit the new communication stream during a temporary admission period,

determine whether the at least one intermediate node can support the QoS requirement of the new communication stream, and

transmit, when the at least one intermediate node is unable to support the QoS requirements of the new communication stream, an indicator which indicates that one or more suggested QoS levels that the at least one intermediate node could provide,

wherein each node further operates to:

receive the indicator including the one or more suggested QoS levels; and

forward the indicator towards the source node that generated the new communication stream so that the source node stops generating packets of the new communication stream;

wherein the source node further operates to, upon receiving the indicator, stop generating packets of the new communication stream, and determine whether the suggested one or more of the QoS levels of the new communication stream will allow admission of the new communication stream along the route.

14. The wireless multi-hop network as claimed in claim 13 , wherein:

one or more intermediate nodes of the at least one intermediate node, which determine that the QoS requirement of the new communication stream can be supported further operate to permit continued transmission of the new communication stream by the source node after the temporary admission period.

15. The wireless multi-hop network as claimed in claim 13 , wherein the the at least one intermediate node further operates to determine, during the temporary admission period, whether that at least one intermediate node is able to support the QoS requirement of the new communication stream along with each of its currently supported communication streams according to QoS requirements associated with each of the currently supported communication streams, and

wherein the at least one intermediate node, which determines that the at least one intermediate node is unable to support one or more of the each of the currently supported communication streams according to the QoS requirements associated with each of the currently supported communication streams of the at least one intermediate node, operates to determine whether a degradation of at least one of the each of the currently supported communication streams by that at least one intermediate node is caused by the new communication stream.

16. The wireless multi-hop network as claimed in claim 15 , wherein the at least one intermediate node further operates to:

determine, upon receiving the new communication stream, whether the new communication stream has at least one metric higher than a metric of any of the currently supported communication streams of the at least one intermediate node; and

admit the new communication stream at the at least one intermediate node when the at least one intermediate node determines that the new communication stream has at least one metric higher than a metric of any of the currently supported communication streams of the at least one intermediate node such that continued transmission of the new communication stream from the source node is permitted by the at least one intermediate node.

17. The wireless multi-hop network as claimed in claim 16 , wherein the at least one intermediate node further operates to determine whether at least one of:

a fraction of time that a channel is busy is below a threshold, and

packet transmission rates of neighbor nodes have not increased by more than a particular percentage; and

wherein the at least one intermediate node operates to suppress transmission of the indicator if at least one of: the fraction of time that the channel is busy is below the threshold; and the packet transmission rates of the neighbor nodes have not increased by more than the particular percentage.

18. The wireless multi-hop network as claimed in claim 13 , wherein each node further operates to:

stop processing of packets of the new communication stream upon receiving the indicator.

19. The wireless multi-hop network as claimed in claim 13 , wherein the wireless multi-hop network further includes:

one or more relay nodes along the route between the source node and the destination node, and wherein the new communication stream is communicated towards the destination node by the one or more relay nodes, and wherein the one or more relay nodes which receive the indicator are further designed to stop relaying of packets of the new communication stream.

20. A node operable to communicate along a route between a source node and a destination node in a wireless multi-hop network, the node comprising:

a receiver designed to receive a new communication stream including a quality of service requirement of the new communication stream from the source node and destined for the destination node;

a processor designed to determine whether the node can support a Quality of Service (QoS) requirement of the new communication stream, and

a transmitter designed to transmit an indicator which indicates that one or more suggested QoS levels that the node could provide to the source node that generated the new communication stream when the node determines it cannot support the QoS requirement of the new communication stream so that the source node stops generating packets of the new communication stream upon receiving the indicator, stops generating packets of the new communication stream, and determines whether the suggested one or more of the QoS levels of the new communication stream will allow admission of the new communication stream along the route.

21. The method as claimed in claim 1 , wherein the one or more suggested QoS requirements for the new communication stream comprise QoS requirements that provide a better chance of being admitted.

22. The method as claimed in claim 1 , further comprising:

transmitting, by a peripheral node an indication that the peripheral node cannot support QoS requirements of its currently supported communication streams,

wherein the peripheral node is not part of the route between the source node and the destination node.