System and method for interference triggered frequency hopping

Abstract

Systems and methods of interference-triggered frequency hopping in a wireless communication system. A master is provided in the wireless communication system in wireless communication with slave nodes each configured to use different preselected communication frequencies to permit frequency hopping. A current channel is selected from among multiple channels in the wireless communication system in which the master and at least some of the slave nodes send and receive wireless communications. Each of the channels uses different ones of the preselected communication frequencies. In the current channel, interference with communications between the master and a selected one of the slave nodes that use the current channel is detected. A new channel is selected only in response to detecting the interference. The system switches from the current channel to the new channel such that communications between the master and the selected slave node use the new channel.

What is claimed is: 
     
         1 . A method of interference-triggered frequency hopping in a wireless communication system, comprising:
 providing in the wireless communication system a master in wireless communication with a plurality of slave nodes configured to use different preselected communication frequencies to permit frequency hopping;   selecting a current channel from among a plurality of channels in the wireless communication system in which the master and at least some of the slave nodes send and receive wireless communications, each of the channels using different ones of the preselected communication frequencies;   detecting interference in the current channel with communications between the master and a selected one of the slave nodes that use the current channel;   selecting a new channel of the channels different from the current channel only in response to detecting the interference; and   switching from the current channel to the new channel such that communications between the master and the selected slave node use the new channel.   
     
     
         2 . The method of  claim 1 , further comprising maintaining wireless communications between the master and the selected slave node in the current channel such that no frequency hopping occurs away from the current channel until interference is detected in the current channel. 
     
     
         3 . The method of  claim 1 , wherein the detecting is carried out by the master or by the selected slave node. 
     
     
         4 . The method of  claim 1 , wherein the selecting the new channel is based on a pre-defined frequency hopping algorithm or a pre-computed frequency hop sequence. 
     
     
         5 . The method of  claim 4 , further comprising, before switching to the new channel, determining a performance associated with a next channel of the channels different from the current channel, and if the performance fails to satisfy a channel performance criterion, selecting a further channel of the channels different from the current channel as the new channel; otherwise, if the performance satisfies the channel performance criterion, assigning the next channel as the new channel. 
     
     
         6 . The method of  claim 5 , wherein the channel performance criterion includes whether interference associated with the next channel is worse than the detected interference in the current channel such that the channel performance criterion is not satisfied if the interference associated with the next channel is worse than the detected interference in the current channel. 
     
     
         7 . The method of  claim 5 , wherein the channel performance criterion includes whether a wireless communication link is established in the next channel between the master and the selected slave node such that the channel performance criterion is not satisfied if the wireless communication link fails within a predefined timeout to be established between the master and the selected slave node. 
     
     
         8 . The method of  claim 4 , further comprising, before switching to the new channel, repeating, for a predetermined number of times:
 determining a performance associated with a next channel of the channels different from the current channel, and if the performance fails to satisfy a channel performance criterion, selecting a further channel of the channels different from the current channel as the new channel; and   if, for any of the further channels selected, the performance fails to satisfy the channel performance criterion for the predetermined number of times, reverting to the current channel without switching to the new channel.   
     
     
         9 . The method of  claim 4 , wherein the pre-defined frequency hopping algorithm includes a random number generator such that the new channel is randomly selected from among the plurality of channels. 
     
     
         10 . The method of  claim 4 , wherein the pre-defined frequency hopping algorithm produces a hop sequence based on parameters, the parameters including a seed, a channel list, and a number of hops. 
     
     
         11 . The method of  claim 4 , wherein the pre-computed frequency hop sequence is based on a seed randomly generated by the master using a characteristic unique to the master, and wherein the frequency hop sequence is calculated by the master or by the selected slave node using the seed and a random number generator function. 
     
     
         12 . The method of  claim 11 , wherein the pre-computed frequency hop sequence is calculated by the master and communicated to the at least some of the slave nodes. 
     
     
         13 . The method of  claim 4 , wherein the switching to the new channel includes announcing a channel switch announcement to the selected slave node, and responsive thereto, the selected slave node carrying out the switching to the new channel as determined by the pre-defined frequency hopping algorithm or in accordance with the pre-computed frequency hop sequence. 
     
     
         14 . The method of  claim 1 , further comprising removing the current channel from a list of channels available for selection responsive to detecting interference. 
     
     
         15 . A non-transitory computer-readable medium encoded with instructions that, when executed by one or more processors, implement a method of interference-triggered frequency hopping in a wireless communication system, the method comprising:
 providing in the wireless communication system a master in wireless communication with a plurality of slave nodes configured to use different preselected communication frequencies to permit frequency hopping;   selecting a current channel from among a plurality of channels in the wireless communication system in which the master and at least some of the slave nodes send and receive wireless communications, each of the channels using different ones of the preselected communication frequencies;   detecting interference in the current channel with communications between the master and a selected one of the slave nodes that use the current channel;   selecting a new channel of the channels different from the current channel only in response to detecting the interference; and   switching from the current channel to the new channel such that communications between the master and the selected slave node use the new channel.   
     
     
         16 . The computer-readable medium of  claim 15 , further comprising maintaining wireless communications between the master and the selected slave node in the current channel such that no frequency hopping occurs away from the current channel until interference is detected in the current channel. 
     
     
         17 . The computer-readable medium of  claim 15 , wherein the detecting is carried out by the master or by the selected slave node. 
     
     
         18 . The computer-readable medium of  claim 15 , wherein the selecting the new channel is based on a pre-defined frequency hopping algorithm or a pre-computed frequency hop sequence. 
     
     
         19 . The computer-readable medium of  claim 18 , further comprising, before switching to the new channel, determining a performance associated with a next channel of the channels different from the current channel, and if the performance fails to satisfy a channel performance criterion, selecting a further channel of the channels different from the current channel as the new channel; otherwise, if the performance satisfies the channel performance criterion, assigning the next channel as the new channel. 
     
     
         20 . The computer-readable medium of  claim 19 , wherein the channel performance criterion includes whether interference associated with the next channel is worse than the detected interference in the current channel such that the channel performance criterion is not satisfied if the interference associated with the next channel is worse than the detected interference in the current channel. 
     
     
         21 . The computer-readable medium of  claim 18 , further comprising, before switching to the new channel, repeating, for a predetermined number of times:
 determining a performance associated with a next channel of the channels different from the current channel, and if the performance fails to satisfy a channel performance criterion, selecting a further channel of the channels different from the current channel as the new channel; and   if, for any of the further channels selected, the performance fails to satisfy the channel performance criterion for the predetermined number of times, reverting to the current channel without switching to the new channel.   
     
     
         22 . The computer-readable medium of  claim 18 , wherein the pre-defined frequency hopping algorithm includes a random number generator such that the new channel is randomly selected from among the plurality of channels. 
     
     
         23 . The computer-readable medium of  claim 18 , wherein the pre-defined frequency hopping algorithm produces a hop sequence based on parameters, the parameters including a seed, a channel list, and a number of hops. 
     
     
         24 . The computer-readable medium of  claim 18 , wherein the pre-computed frequency hop sequence is based on a seed randomly generated by the master using a characteristic unique to the master, and wherein the frequency hop sequence is calculated by the master or by the selected slave node using the seed and a random number generator function. 
     
     
         25 . The computer-readable medium of  claim 18 , wherein the switching to the new channel includes announcing a channel switch announcement to the selected slave node, and responsive thereto, the selected slave node carrying out the switching to the new channel as determined by the pre-defined frequency hopping algorithm or in accordance with the pre-computed frequency hop sequence. 
     
     
         26 . The computer-readable medium of  claim 15 , further comprising removing the current channel from a list of channels available for selection responsive to detecting interference.