Off network mobile to mobile calling using SIP protocol
View Patent ↗This invention addresses the need to transport high bit-rate data to multiple users, or between users, over wired and wireless means. Specifically, this disclosure describes a new method of enabling communication from mobile phone to mobile phone when no network services are available as long as radio contact between the mobile handsets is possible by reserving un-assigned timeslots in the medium access control protocol super frame structure.
1. A method of allowing direct communication between two or more mobile handsets without disrupting a wireless network controlled by a base station and other users in the network used for wireless voice over Internet protocol communications comprising:
each of said mobile handsets having a medium access control protocol for wireless communication on a voice over Internet protocol network;
said medium access control protocol having timeslots and containing a session initiation protocol that enables a mobile handset to use voice over Internet protocol to access the Internet;
two or more mobile handsets being within radio range of each other;
each of said mobile handsets having two assigned timeslots in said medium access control protocol during which digital voice packets are transferred to and from the base station during normal network operations;
said base station having two or more reserved timeslots in said medium access control protocol not available to be assigned to any of said mobile handsets joining said voice over Internet protocol network controlled by said base station;
said mobile handsets capable of detecting when a network signal is present and when both of said mobile handsets detect a network signal said mobile handsets communicating directly between each other without the use of or interference with said base station using said reserved timeslots, and when only one of said mobile handsets detects a network signal the mobile handset detecting the network signal relays timing information to the mobile handset not detecting the network signal and then said mobile handsets communicating directly between each other without the use of or interference with said base station using said reserved timeslots, and when neither of said mobile handsets detects a network signal said mobile handsets communicating directly between each other without the use of or interference with said base station using any network timeslots; and,
when any additional mobile handset beginning a call when a network signal is not present but other mobile handsets are in communication directly between each other without use of or interference with said base station then said additional mobile handset synchronizing to said medium access control protocol being used by the directly communicating mobile handsets and using any network timeslots other than the network timeslots being used by the directly communicating mobile handsets.