Blackberry Corporation

Research in Motion Corporation

Ximing Zeng

Zhigang Ruan

Valentina Iqorevna Kramarenko

Christopher Edward Prest

Michael Elizarov

Alexander Shatsky

Dapeng Gao

Abhinav Gupta

Jerod David Klink

Valentina Iquorevna Kramarenko

A system, method and mobile device for initiating a voice call from the mobile device is provided. An expiration time is determined based on a time reference synchronized with a mobile call server. The mobile device transmits to the mobile call server a session initiation protocol (SIP) call initiation request including a destination number and the expiration time. A second call initiation request to a secondary contact number is initiated to establish the voice call to the destination number, when a response to the SIP call initiation request is not received from the mobile call server prior to the expiration time enabling reliable establishment of the voice call when the first attempt is unsuccessful. The mobile device does not have to wait on the mobile call server to determine a call failure and ensure that subsequent call initiation by the mobile device does not result in a call establishment collision with the mobile call server.

System, apparatus and method for establishing a call from a mobile device

A method, system and apparatus for managing call handoff are provided. A mobile device engaged in a first media session over a first transport determines a second transport is available. A reflected media session is established via an echo server over the second transport. Quality of the reflected media session is evaluated by determining a call metric based on call transport data received at the mobile device from the mobile device (itself) in the reflected media session. Call handover is requested from the first media session to a second media session over the second transport when the call metric indicates that the quality of the reflected media session meets a threshold.

Method, system and apparatus for managing call handoff

Aspects relate to provision of enterprise call capabilities to mobile devices. For example, a mobile device can indicate, over a data channel, that a PBX is to make a call on its behalf to a called party. The PBX can call back the mobile device, call the called party, and bridge those call legs to establish the call. The mobile device can employ mechanisms that a particular incoming call is made by the PBX. These mechanisms can include using ANI information, sending, and receiving audible verification codes over the voice channel established after answering the incoming call. The verification codes can be selected based different behaviors of the mobile devices.

Error correction for DTMF corruption on uplink

In a method of processing an incoming sequence of one or more DTMF tones at a mobile device, the sequence is decoded to thereby identify any encoded message. Where the decoding does not identify a message, at least applying an error correction algorithm to the sequence to identify a message. Where the algorithm fails to correct the sequence, the sequence is compared to messages currently expected by the mobile device. If a message is not identified, a negative acknowledgement message may be sent. At a server, upon receipt of a negative acknowledgement message, it is determined if a message was sent to the mobile device in a previous pre-determined time window. If so, the message is re-sent. The server repeatedly sends certain messages to a mobile device until an acknowledgement message indicating receipt of the message by the mobile device is received.

DTMF signalling between mobile and server

Systems, methods and devices are disclosed useful for enabling wireless signals representing control messages to be sent between a wireless handheld telephony device and a call control server during an ongoing communication session when an out-of-band path becomes unavailable, the communication session being controlled by the call control server.

Growing community of inventors

Waterloo, Canada

Ximing Zeng