Dual Fallback Hardened VoIP System with Signal Quality Measurement

Abstract

A hardened VoIP system is presented that includes secure push-to-talk voice functionality. Through the addition of encryption, authentication, user filtering, and integration with new and existing LMR systems, a secure voice platform ensures malicious software, unauthorized access and brute force security attacks will not compromise the voice communications of the system. The VoIP system is engineered to ensure graceful system degradation in the event of maintenance activities, natural disasters and failure modes. The hardened VoIP system offers the functions a LMR trunking system while utilizing broadband connections. Private calls, group calls, Emergency Alarms with covert monitoring capability, scanning and priority scanning may be incorporated into the system. The system includes a VoIP controller that serves as a trunking controller, manages available VoIP based conference bridges, and assigns them as needed to the parties involved in each voice call. The system includes multiple fallback methods that may be prioritized based on pre-failure analytics.

We claim: 
     
         1 . A system for providing hardened Voice over Internet Protocol (VoIP) and land mobile radio communication services to mobile devices, the system comprising:
 a mobile device and a controller having a first primary operational state, a secondary primary operational state, a first fallback state, and a second fallback state,   the controller configured
 in the first primary operational state to
 receive via a cellular communications system
 a first VoIP heartbeat signal from the mobile device, 
 
 receive a first Land Mobile Radio (LMR) status signal associated with a first land mobile radio system from the mobile device, 
 maintain a database with
 a first identifier associating the first mobile device with the cellular communications system and 
 a second identifier associating the first mobile device with the first land mobile radio system; 
 
 
 in the second primary operational state to
 receive via the cellular communications system
 the first VoIP heartbeat signal from the mobile device, 
 
 receive a second LMR status signal associated with a second land mobile radio system from the mobile device, 
 maintain the database with
 the first identifier associating the first mobile device with the cellular communications system and 
 the second identifier associating the first mobile device with the second land mobile radio system; 
 
 
 in the second primary operational state to
 receive via a cellular communications system
 the first VoIP heartbeat signal from the mobile device, 
 
 receive via a second land mobile radio system
 a second LMR status signal, 
 
 transmit a first status control signal to the first mobile device, and 
 maintain a database with
 a first identifier associating the first mobile device with the cellular communications system and 
 a second identifier associating the first mobile device with the second land mobile radio system; 
 
 
 in the first fallback state to
 monitor a channel of the first land mobile radio system associated with the mobile device; 
 
 in the second fallback state to
 monitor a channel of the second land mobile radio system associated with the mobile device; 
 
 to transition from the first primary operational state to the first fallback state upon failing to receive the first VoIP heartbeat signal from the mobile device; and 
 to transition from the second primary operational state to the second fallback state upon failing to receive the first VoIP heartbeat signal from the mobile device. 
   
     
     
         2 . The system of  claim 1  wherein
 the controller is configured to transition from the first primary operational state to the second primary operational state upon receipt of a first message indicating the mobile device has secondary voice access. 
 
     
     
         3 . The system of  claim 1  wherein
 the controller is configured to determine a signal quality of the cellular communications system with a Session Initiation Protocol/Real-Time Transport Control Protocol, and transition from the first primary operational state to the first fallback state upon the signal quality passing a predetermined threshold. 
 
     
     
         4 . The system of  claim 1  wherein
 the second identifier associating the first mobile device with the first land mobile radio system includes a first frequency; 
 the second identifier associating the first mobile device with the second land mobile radio system includes a second frequency; and 
 the first frequency is different than the second frequency. 
 
     
     
         5 . The system of  claim 1  wherein the controller is configured to transition from the second primary operational state to the first primary operational state upon receiving the first LMR status signal. 
     
     
         6 . The system of  claim 1  wherein
 the mobile device is configured to
 determine a signal quality of the cellular communications system with a Session Initiation Protocol/Real-Time Transport Control Protocol, and 
 
 the controller is configured to transition from the first primary operational state to the first fallback state upon the signal quality passing a predetermined threshold. 
 
     
     
         7 . The system of  claim 6  wherein
 the mobile device is configured to use a measurement of at least one of packet loss and latency in determining the signal quality. 
 
     
     
         8 . The system of  claim 6  wherein the
 controller is configured to transition from the first primary operational state to the first fallback state upon the signal quality passing the predetermined threshold when the controller is receiving the first LMR status signal. 
 
     
     
         9 . The system of  claim 1  wherein
 the mobile device and the controller both have the first primary operational state, the secondary primary operational state, the first fallback state, and the second fallback state; 
 the mobile device further includes a first auxiliary data state and a second auxiliary data state; 
 the controller and mobile device configured
 in the first auxiliary data state to
 send to the mobile device via an auxiliary data communications system
 an auxiliary data status signal from the controller, 
 
 receive at the controller the first LMR status signal from
 the first land mobile radio system, and 
 
 provide VoIP communication over the auxiliary data communications system; 
 
 in the second auxiliary data state to
 send to the mobile device via the auxiliary data communications system the auxiliary data status signal from the controller, 
 receive at the controller the second LMR status signal from the second land mobile radio system, and 
 provide VoIP communication over the auxiliary data communications system; 
 
 to transition from the first auxiliary data state to the first fallback state upon the mobile device failing to receive the auxiliary data status signal from the controller; 
 to transition from second auxiliary data state to the second fallback state upon the mobile device failing to receive the auxiliary data status signal from the controller; and 
 to transition from the first auxiliary data state to the second auxiliary data state upon the controller failing to receive the first LMR status signal. 
 
 
     
     
         10 . The system of  claim 9  wherein the mobile device and controller are further configured
 to transition from the first primary operational state to first auxiliary data state upon the controller failing to receive the first VoIP heartbeat signal from and the mobile device receiving the auxiliary data status signal; and 
 to transition from the first primary operational state to first fallback state upon the controller failing to receive the first VoIP heartbeat signal and the mobile device failing to receive the auxiliary data status signal. 
 
     
     
         11 . The system of  claim 9  wherein
 the cellular communications system and auxiliary data communications system include a network pairing selected from a group consisting of two of 3G, 4G, GSM, LTE, CDMA, and 5G NR. 
 
     
     
         12 . The system of  claim 1  wherein
 the controller is configured to
 determine a signal quality of the cellular communications system with a Session Initiation Protocol/Real-Time Transport Control Protocol, and 
 transit a fallback command to the mobile device upon the signal quality passing a predetermined threshold. 
 
 
     
     
         13 . The system of  claim 12  wherein
 the mobile device and the controller both have the first primary operational state, the secondary primary operational state, the first fallback state, and the second fallback state; and 
 the mobile device is configured to transition from the first primary operational state to the first fallback state upon receipt of the fallback command from the controller. 
 
     
     
         14 . The system of  claim 12  wherein
 the system is configured to utilize a measurement of at least one of packet loss and latency in determining the signal quality of the cellular communications system. 
 
     
     
         15 . The system of  claim 1  wherein
 the controller is configured to verify receipt of the first VoIP heartbeat signal from the mobile device at the expiration of a timer having a duration; 
 at least one of the controller and the mobile device is configured to determine a signal quality of the cellular communications system with a Session Initiation Protocol/Real-Time Transport Control Protocol; and 
 the duration of the timer decreases upon the signal quality passing a predetermined threshold. 
 
     
     
         16 . The system of  claim 1  wherein
 the mobile device is configured to transmit a message to the controller upon 
 the transition of the from the first primary operational state to the second primary operational state indicating the mobile device has secondary voice access.