Distributed scheduler design for multiuser detection enabled wireless mobile ad-hoc networks
In the method for operating an interference multiple access communications system, wherein the improvement comprises the steps of employing a distributed scheduler within a Media Access Controller (MAC) for Multiuser Detection (MUD) enabled Mobile Ad-hoc Networks (MANETS) to increase spectral efficiency by increasing spectral use and providing a way to dynamically allocate virtual channels to achieve maximum channel reuse in different network topologies and different link patterns and to ameliorate any hidden or exposed node problems.
1. A system for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for multiuser detection (MUD) channel reuse, the system comprising:
a transceiver configured to receive a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
a processor configured to, based on an algorithm:
determine from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes, wherein the plurality of resource usage maps reflect a status of slot codes as one of FREE, RX, TX, and BUSY; and
determine, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
a scheduler configured to schedule transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node.
2. The system of claim 1 , wherein the transceiver is configured to transmit data packets from the first node to the destination node according to a transmission schedule determined by the scheduler.
3. The system of claim 1 , wherein the resource availability criteria is configured to avoid collision of the transmission of data from the first node to the destination node with data transmitted at the same time and on the same frequency from other network nodes.
4. The system of claim 1 , wherein the scheduler is configured to schedule transmissions taking at least one of hidden nodes and exposed nodes into account.
5. The system of claim 1 , wherein the scheduler is configured to schedule transmissions allowing multiple transmissions in a code slot to achieve maximum channel reuse as long as neighboring nodes do not receive on the same slot-code.
6. The system of claim 1 , wherein the scheduler is configured to schedule transmissions between the first node and the destination node when certain other nodes cannot hear at least one of the first node and the destination node.
7. The system of claim 1 , wherein the scheduler is configured to schedule transmissions so that the first node can transmit on a code-slot on which its 1 hop neighbors only observe transmission on the code-slot but do not receive on the code-slot, and if its 1 hop neighbors receive on some codes in a slot, no multiple transmissions are allowed on any individual codes in the slot.
8. The system of claim 1 , wherein the scheduler is configured to schedule transmissions so that an allowed transmission occurs when multiple nodes are transmitting on one slot and one code and wherein another node is permitted to transmit because neither of the neighbors of said another node receives in the slot and on the code used by said multiple transmitting nodes.
9. A system for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for multiuser detection (MUD) channel reuse, the system comprising:
a transceiver configured to receive a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
a processor configured to, based on an algorithm:
determine from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes; and
determine, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
a scheduler configured to schedule transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node,
wherein the resource availability criteria are that no 1-hop neighbors are receiving on a slot-code, thus to avoid collision, the destination node doesn't transmit in the code slot, thus satisfying the half-duplex constraint at the receiver;
the destination node doesn't receive on the slot-code, thus to avoid collision; the destination node doesn't have the slot-code marked as “busy”, which is to avoid collision; and
a local node neither transmits nor receives in the slot, as only one transmission is possible per slot, thus satisfying the half-duplex constraint at the transmitter.
10. A system for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for multiuser detection (MUD) channel reuse, the system comprising:
a transceiver configured to receive a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
a processor configured to, based on an algorithm:
determine from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes; and
determine, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
a scheduler configured to schedule transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node, wherein the scheduler is configured to:
calculate a desired number of transmit code slots for data packets to be transmitted along with an identification of the destination node; and
find, based on the desired number of transmit code slots and the identification of the destination node, available code slots by applying the availability criteria to information from a resource usage table derived from the resource usage maps that compiles all of the nodes views of all of the transmit and receive conditions of all of the nodes.
11. A method for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for MUD channel reuse, the method comprising:
receiving a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
determining from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes, wherein the plurality of resource usage maps reflect a status of slot codes as one of FREE, RX, TX, and BUSY;
determining, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
scheduling transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node.
12. The method of claim 11 , comprising transmitting data packets from the first node to the destination node according to a transmission schedule determined by the scheduler.
13. The method of claim 11 , wherein scheduling transmissions includes avoiding collision of the transmission of data from the first node to the destination node with data transmitted at the same time and on the same frequency from other network nodes.
14. The method of claim 11 , wherein scheduling transmissions includes taking at least one of hidden nodes and exposed nodes into account.
15. The method of claim 11 , wherein scheduling transmissions includes allowing multiple transmissions in a code slot to achieve maximum channel reuse as long as neighboring nodes do not receive on the same slot-code.
16. The method of claim 11 , wherein scheduling transmissions includes scheduling transmissions between the first node and the destination node when certain other nodes cannot hear at least one of the first node and the destination node.
17. The method of claim 11 , wherein scheduling transmissions includes scheduling transmissions so that a node can transmit on a code-slot on which its 1 hop neighbors only observe transmission on the code-slot but do not receive on the code-slot, and if its 1 hop neighbors receive on some codes in a slot, no multiple transmissions are allowed on any individual codes in the slot.
18. The method of claim 11 , wherein scheduling transmissions includes schedule transmissions so that an allowed transmission occurs when multiple nodes are transmitting on one slot and one code and wherein another node is permitted to transmit because neither of the neighbors of said another node receives in the slot and on the code used by said multiple transmitting nodes.
19. A method for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for MUD channel reuse, the method comprising:
receiving a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
determining from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes;
determining, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
scheduling transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node,
wherein the resource availability criteria are that no 1-hop neighbors are receiving on the slot-code, thus to avoid collision, the destination node doesn't transmit in the code slot, thus satisfying the half-duplex constraint at the receiver;
the destination node doesn't receive on the slot-code, thus to avoid collision; the destination node doesn't have the slot-code marked as “busy”, which is to avoid collision; and
a local node neither transmits nor receives in the slot, as only one transmission is possible per slot, thus satisfying the half-duplex constraint at the transmitter.
20. A method for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for MUD channel reuse, the method comprising:
receiving a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
determining from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes;
determining, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
scheduling transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node, wherein scheduling transmissions includes:
calculating a desired number of transmit code slots for data packets to be transmitted along with an identification of the destination node; and
finding, based on the desired number of transmit code slots and the identification of the destination node, available code slots by applying the availability criteria to information from a resource usage table derived from the resource usage maps that compiles all of the nodes views of all of the transmit and receive conditions of all of the nodes.
21. A non-transitory computer readable medium storing a computer program, executable by a machine, for scheduling transmissions by a first node in a multiuser detector enabled mobile ad-hoc network for MUD channel reuse, the computer program comprising executable instructions for:
receiving a plurality of control messages including identities and transmit and receive conditions of a plurality of remote nodes;
determining from the received plurality of control messages a plurality of resource usage maps corresponding to the plurality of remote nodes, wherein the plurality of resource usage maps reflect a status of slot codes as one of FREE, RX, TX, and BUSY;
determining, based on combined information from the plurality of resource usage maps and resource availability criteria, an availability of code slots for receiving packets at a destination node; and
scheduling transmissions of packets from the first node to the destination node within the mobile ad-hoc network based on the determined availability of code slots for receiving packets at the destination node.