Distributed Overlay Multi-Channel Media Access Control (MAC) for Wireless Ad Hoc Networks

Abstract

Systems and methods for distributed overlay multi-channel MAC for wireless ad hoc networks are described. In one aspect, the systems and methods divide channel frequencies defined by a wireless network protocol into a single home channel and multiple guest channels that are orthogonal to the home channel. Each of the network nodes in the ad hoc network operates on the home channel for respective variable and overlapping amounts of time to maintain network connectivity with other respective network nodes. Additionally, each of the network nodes determines whether and when to switch from the home channel to a particular guest channel of the guest channels for a variable amount of time to increase data throughput over one or more corresponding communication links in the ad hoc network with other network node(s).

1 . A computer-implemented method, the method comprising:
 receiving at a node on a multiple node ad hoc network, a beacon signal, the beacon signal indicating the beginning of a beacon interval;
 the node operating on a home channel frequency, for a variable amount of time to maintain network connectivity with other nodes on the ad hoc network; 
 maintaining traffic information of the ad hoc network, the traffic information comprising information as to which nodes in the ad hoc network have active links in primary conflict; and 
 determining a pole point, the pole point scheduling when the node is to switch to a guest channel frequency orthogonal to the home channel, and the determining based on the maintained traffic information. 
   
   
   
       2 . The computer-implemented method of  claim 1 , wherein the maintaining traffic information is performed at the node, and wherein the determining a pole point is performed at the node. 
   
   
       3 . The computer-implemented method of  claim 2 , wherein the determining is performed prior to receiving at the node, a second beacon signal, the second beacon signal indicating the end of the beacon interval. 
   
   
       4 . The computer-implemented method of  claim 2 , wherein the traffic information comprises traffic volume of at least one of the active links. 
   
   
       5 . The computer-implemented method of  claim 2 , wherein the determining a pole point comprises calculating a proportional to cycle time. 
   
   
       6 . The computer-implemented method of  claim 2 , wherein the traffic information maintained by the node is limited to traffic information of one-hop neighbor nodes of the node. 
   
   
       7 . The computer-implemented method of  claim 1 , wherein the maintaining traffic information is performed at a central location accessible to all nodes on the ad hoc network; and the determining a pole point is performed at the central location. 
   
   
       8 . The computer-implemented method of  claim 7 , wherein the determining a pole point is to schedule switching to the guest channel frequency asynchronously, with respect to the guest channel frequency determinations of the other nodes. 
   
   
       9 . A computer-implemented method, the method comprising:
 scanning at an initiator node, available channel frequencies of a multiple node ad hoc network;   the initiator node selecting a home channel frequency on the basis of the scanning;   the initiator node broadcasting the home channel frequency selection to at least one other node on the ad hoc network;   receiving at the initiator node one or more messages, each message comprising network channel frequency scanning results by another node on the ad hoc network; and   determining whether or not to switch to the selected home channel frequency on the basis of the one or more messages.   
   
   
       10 . The computer-implemented method of  claim 9 , the method comprising: defining available channel frequencies, other that the selected home channel frequency, as guest channel frequencies of the ad hoc network. 
   
   
       11 . The computer-implemented method of  claim 9 , wherein the scanning at the initiator node comprises measuring noise levels on each of the available channels, and wherein the selecting of the home channel frequency is a selecting of the available channel with the least noise. 
   
   
       12 . The computer-implemented method of  claim 9 , wherein the one or more messages comprise votes on whether or not to switch to the selected home channel frequency, and wherein the determining whether or not to switch to the selected home channel frequency is based on a percentage of votes exceeding a predetermined percentage. 
   
   
       13 . The computer-implemented method of  claim 9 , wherein the initiator node has an active link with an original home channel frequency, and wherein the broadcasting the home channel frequency selection comprises requesting other nodes to migrate from the original home channel frequency to the home channel frequency selection. 
   
   
       14 . The computer-implemented method of  claim 13 , the method comprising redefining the original home channel frequency to a guest channel frequency. 
   
   
       15 . A node apparatus on an ad hoc network, the apparatus comprising:
 an overlay multi-channel media access control (OMMAC), the OMMAC comprising:   a traffic measurement component, and   a channel switching scheduler;   a program data component, the program data component comprising:   a channel set including a home channel frequency and at least one guest channel frequency,   a pole point, the pole point indicating when the node is scheduled to switch to a guest channel frequency orthogonal to the home channel, and   traffic information of the ad hoc network, the traffic information comprising information as to which nodes in the ad hoc network have active links in primary conflict;   the traffic measurement component configured to collect the traffic information; and   the channel switching scheduler configured to set any one of the home channel frequency, guest channel frequency, or pole point, on the basis of the traffic information.   
   
   
       16 . The apparatus of  claim 15 , wherein the traffic information comprises traffic volume of at least one the active links. 
   
   
       17 . The apparatus of  claim 15 , wherein the traffic information maintained by the node is limited to traffic information of one-hop neighbor nodes of the node. 
   
   
       18 . The apparatus of  claim 15 , wherein the traffic information comprises a Maximal Independent Set (MIS) stored in a graph, the MIS comprising the largest set of links with non-primary conflicts. 
   
   
       19 . The apparatus of  claim 18 , wherein the traffic information comprises a traffic node graph of the ad hoc network, and a link graph of links with primary conflicts. 
   
   
       20 . The apparatus of  claim 18 , wherein the channel switching scheduler is configured to calculate the MIS using a least degree first greedy algorithm.