A handover technique in a cellular radio communication system (100) for handing over a radio (102) from a first channel in a first cell to a second channel in a second cell, the technique comprising generating a fill-in message extrapolated from a message of the radio on the first channel and communicating the fill-in message when the radio has ceased communicating on the first channel; and terminating the fill-in message when the radio begins communicating on the second channel, thereby reducing handover disruption. The messages may be digitized audio messages. A timer (110, 118) may be employed to allow the fill-in message to terminate at substantially the same time as the radio begins communicating on the second channel. Alternatively, the fill-in message may be directly terminated (FIG. 2) in response to the radio beginning to communicate on the second channel. If the messages are data messages, no fill-in message is generated and the handover is completed directly (FIG. 2) in response to the radio beginning to communicate on the second channel.
The present invention provides a method of handing off a communication unit in a cellular communication system. The method includes communicating initialization frame data from a target cell transceiver to a base site transcoder; establishing communication between the target cell transceiver and the communication unit; terminating transmission of initialization frame data; communicating ordinary frame data received by the target cell transceiver from the communication unit to the base site transcoder; and handing off the communication unit to the target cell transceiver upon detecting a transition from initialization frame data to ordinary frame data at the base site transcoder.
The present invention switch transcoder (18) provides transcoding of speech for a cellular system in which speech from a plurality of E1 lines (7) may be compressed for outputting to a much smaller number of T1 lines (8) so that multiple conversations greater in number than previously possible can be carried on at the same time. The transcoding and switching of speech between the E1 and T1 lines are effected on a single module (30) which has thereon the control processor (42), voice processors (44) and appropriate interfaces (36, 40).
A speech signal is transmitted over a radio path by a mobile station, and is received in a first base station. The speech signal, encoded using encoding parameters, is forwarded in the information frames from the first base station to a remotely located speech decoder. Each of the information frames carries a synchronization word and a synchronization check bit recurring at predetermined intervals within the information frame. The information frames are received at the remote speech decoder. The remote speech decoder is synchronized with one of the received information frames using the synchronizing word. Speech encoding parameters are extracted from the received information frames, and the recurring synchronization check bit is monitored within the received information in order to detect an error in the recurring synchronization check bit in the received information frames.
A communication system (100) comprises a central controller (102), a plurality of base stations (104 and 106) coupled indirectly via the central controller and using radio frequency waves to communicate to communication unit(s), one of the base stations being a source base station (104) and at least another base station being a destination base station (106), and at least one communication unit (108) operable on the base stations. The communication system is able to synchronize a handoff of the communication unit between the source base station to the destination base station, wherein the source base station is the originating communication resource for the communication unit and the destination base station is the recipient communication resource for the communication unit subsequent to the handoff.
A method and apparatus for handoff to a rescue channel is introduced without the need to send and receive handoff control messages. In the preferred embodiment of the present invention, coordination of the rescue procedure at the infrastructure and mobile station is provided first by disabling the mobile transmitter followed by subsequent detection of signal loss and frame erasures at the serving cells, then by enabling the mobile transmitter followed by subsequent detection of signal by a rescue cell, and finally by enabling the rescue cell channel transmitter followed by subsequent detection and reception of signal and frames by the mobile.
