Abstract: A method and apparatus for automatically switching functions associated with a leading radio to another radio on a channel is disclosed. The method includes receiving, from a leading radio by at least one other radio operating on a channel, an associated timing signal via at least one control timing message. Other radios use the timing signal to synchronize transmissions made on the channel. The method also includes receiving, by the other radios, an indication that the leading radio can no longer provide control timing messages. The method further includes maintaining, by each radio on the channel, values for various elements associated with radios operating on the channel and selecting a new leading radio from the other radios based on priorities of the various elements.

Abstract: A process for consolidating location-dependent information in a two-way radio system includes determining a geographic location of each subscriber unit in a group of subscriber units active within a radio frequency (RF) coverage area of a base station (BS), determining a single representative geographic location for the group of subscriber units based on their geographic locations, requesting location-dependent information from a content provider using the representative geographic location, and causing the location-dependent information to be broadcast within the RF coverage area.

Abstract: In operation, a transmitting device selects a synchronization pattern associated with the desired timeslot that is at least mutually exclusive from synchronization patterns associated with other timeslots on the same frequency in the system. Once selected, the transmitting device transmits a burst embedding the synchronization pattern that was selected, where appropriate. If the receiving device detects the synchronization pattern, it immediately synchronizes with the timeslot with confidence that it is synchronizing to the desired timeslot by using sets of synchronization patterns associated with the desired timeslot that are at least mutually exclusive from synchronization patterns associated with the other timeslots on the same frequency.

Abstract: A wireless method, apparatus, and system provide simultaneous transacting of voice and data on adjacent timeslots through a combination of channel access rules and sacrificing small audio portions when required. This includes wirelessly operating on at least two timeslots which are adjacent to one another, operating voice on a first timeslot of the at least two timeslots and monitoring a second timeslot of the at least two timeslots for data, and, responsive to a data transmission request and receiving voice on the first timeslot, discarding a portion of the voice in the first timeslot to provide a larger guard time for programming between the first timeslot and the second timeslot and transmitting data in the second timeslot based on the data transmission request.

Abstract: A method for enabling full duplex direct mode calls between radios in an N:1 slotting ratio TDMA radio system includes detecting a request for a full duplex direct mode call at a first radio, transmitting in a particular slot of a first recurring time slot of N recurring time slots on a first single frequency one of a call request and a call header identifying the call as a full duplex call. Subsequently transmitting, by the first radio, during a plurality of subsequent first recurring time slots, outbound voice and/or data transmissions. And receiving, during a plurality of second recurring time slots of the N recurring time slots, each second recurring timeslot positioned immediately adjacent a respective first recurring time slot in an interleaved manner, inbound voice and/or data transmissions from the second radio and playing back the inbound voice and/or data transmission at the first radio.

Abstract: A first subscriber unit (SU) operating in a two-way radio frequency (RF) communications system having at least one fixed terminal, one or more channels, and a plurality of subscriber units, generates a first burst of data for transmission to the at least one fixed terminal. The first SU calculates a cyclic redundancy check (CRC) or checksum value over (i) at least a first portion of the first burst of data and (ii) at least a portion of a first private data. The first SU transmits the first burst of data and the calculated CRC/checksum value, but not the first private data, to the at least one fixed terminal. The fixed terminal then calculates its own CRC/checksum over the received burst and its own copy of the first private data, and compares the result with the received CRC/checksum. The fixed terminal authenticates the received burst if the values match.

Abstract: A process for resolving call collisions in a digital conventional direct mode includes monitoring a direct mode communication channel for transmissions from other direct mode radios in the plurality of direct mode radios. In response to detecting a new call request: identifying a last radio to transmit on the direct mode channel, transmitting a new call request for receipt by the last direct mode radio to transmit, monitoring the direct mode channel for a response from the last radio to transmit, and if a call grant granting the new call request is received from the last radio to transmit, initiating the new direct mode call on the direct mode communication channel. If the call grant is not received, at least temporarily refraining from initiating the new direct mode call.

Abstract: A process for resolving call collisions in a digital conventional direct mode includes monitoring a direct mode communication channel for transmissions from other direct mode radios in the plurality of direct mode radios. In response to detecting a new call request: identifying a last radio to transmit on the direct mode channel, transmitting a new call request for receipt by the last direct mode radio to transmit, monitoring the direct mode channel for a response from the last radio to transmit, and if a call grant granting the new call request is received from the last radio to transmit, initiating the new direct mode call on the direct mode communication channel. If the call grant is not received, at least temporarily refraining from initiating the new direct mode call.

Abstract: A process for consolidating location-dependent information in a two-way radio system includes determining a geographic location of each subscriber unit in a group of subscriber units active within a radio frequency (RF) coverage area of a base station (BS), determining a single representative geographic location for the group of subscriber units based on their geographic locations, requesting location-dependent information from a content provider using the representative geographic location, and causing the location-dependent information to be broadcast within the RF coverage area.

Abstract: An updated group alias, based on one or more of a location, function, and purpose of a group, is transmitted to a subscriber unit (SU) and displayed at the SU, in place of a previously provisioned group ID or group alias associated with the group, during communications with, or when the SU is tuned to, the group. An incident ID, associated with one or more groups and identifying an incident, is received and stored at a SU. The SU embeds the stored incident ID in all future communications with the one or more groups and, upon request, scans a set of groups and/or channels for communications having the incident ID embedded therein. An incident ID alias described one or more of a name, location, function, or purpose of the incident, may also be received and associated with the incident ID.

Abstract: A new group call request is received from a subscriber station at a rest channel repeater at a first network location. Corresponding new group call notifications are then transmitted to each of the other network locations over a wide area network to a current one of the repeaters acting as a rest channel repeater at each of the other network locations. Subsequently, an identity of a traffic channel repeater hosting the new call is received from each of the respective other network locations. An over-the-air notification is transmitted to other subscriber stations at the first network location identifying one of the first rest channel and another available channel as a channel for the new group call. Data received from the first subscriber station is then forwarded to each of the identified traffic channel repeaters at each of the other network locations via the wide area network.

Abstract: An updated group alias, based on one or more of a location, function, and purpose of a group, is transmitted to a subscriber unit (SU) and displayed at the SU, in place of a previously provisioned group ID or group alias associated with the group, during communications with, or when the SU is tuned to, the group. An incident ID, associated with one or more groups and identifying an incident, is received and stored at a SU. The SU embeds the stored incident ID in all future communications with the one or more groups and, upon request, scans a set of groups and/or channels for communications having the incident ID embedded therein. An incident ID alias described one or more of a name, location, function, or purpose of the incident, may also be received and associated with the incident ID.

Abstract: A method for detecting a channel in a mixed-mode communications system is presented. The channel contains a primary synchronization pattern in a predetermined location within the channel. The primary synchronization pattern is compared against different predetermined channel synchronization patterns to detect a channel. Upon detection of the channel, a look-back channel detector confirms the existence of the channel by using the location of the primary synchronization pattern. Detection and confirmation of the channel may be employed simultaneously to each channel of a multiple-channel direct mode of operation signal. Audio holes may be eliminated in a 2:1 TDMA direct mode operation where both time slots contain signals from two different originating communication devices and the signals have different priority.

Abstract: A method and device for sharing synchronized direct mode time division multiple access (TDMA) timeslots among a plurality of direct mode radios includes monitoring, by a first direct mode radio, other radios' usage of a plurality of available timeslots on a direct mode radio frequency (RF) and, for each received new transmission, storing an indication of the timeslot used by the new transmission and storing a system partitioning identifier associated with the new transmission. Dynamically determining, by the first radio and as a function of the monitoring, a first preferred transmit timeslot determined to be less likely to interfere with the other direct mode radios. Responsive to detecting a request to transmit a new direct mode call, first determining if the first preferred transmit timeslot is available, and if so, transmitting the new call in the first preferred transmit timeslot on the direct mode radio frequency.

Abstract: Disclosed is a method of automatic establishment of a location-based talk group call with reduced messaging overhead. The initiating device may be a subscriber unit (SU). The SU determines a geographic reference location and generates location data representative of the location. The SU broadcasts a location-based talk group call header including the location data and including a location-based talk group call identifier field set to cause other SUs receiving the call header to receive and output subsequent data associated with the call header responsive to determining that its current geographic location satisfies the location criterion of the call. The location criterion may be fully determined by the initiating SU and specified in the call header, and may take the form of a specified radius that extends from the geographic reference location represented in the call header.

Abstract: A method and apparatus for enabling a radio to track channel timing and support channel scanning A non-leading radio operating on a communications channel, determines a diffusion period during which channel timing is to be propagated from a leading radio to non-leading radios operating on the communications channel. The non-leading radio implements a first scanning pattern during the diffusion period to scan a CT designated channel for a control timing message with a timing signal sent from the leading radio. The first scanning pattern involves scanning the CT designated channel during every other scan interval and scanning non-priority channels and priority channels during scan intervals not used on the CT designated channel.

Abstract: A system and method for interrupting a transmitting device during a call. In the system, calls are transmitted from a first device on a communication channel as a series of channel frames. At predetermined times during the transmission, the transmitting device is configured to drop channel frames, resulting in open channel frame periods where the transmitting device is not transmitting on the communication channel. During these open channel frame periods, the transmitting device is also configured to switch to a receiving mode. Other devices in the system are capable of switching into a transmitting mode during the open channel frame periods and, when applicable, sending an interrupt request on the communication channel to the transmitting device in order to request access to the channel.

Abstract: A system and method for interrupting a transmitting device during a call. In the system, calls are transmitted from a first device on a communication channel as a series of channel frames. At predetermined times during the transmission, the transmitting device is configured to drop channel frames, resulting in open channel frame periods where the transmitting device is not transmitting on the communication channel. During these open channel frame periods, the transmitting device is also configured to switch to a receiving mode. Other devices in the system are capable of switching into a transmitting mode during the open channel frame periods and, when applicable, sending an interrupt request on the communication channel to the transmitting device in order to request access to the channel.

Abstract: A method is disclosed for determining a connectivity status of radios in a coverage group. Each coverage group includes radios configured to transmit and receive range messages on a channel and a timeslot. Each radio in the coverage group is configured to generate a range message and to transmit the range message to each other radio in the coverage group. Each radio in the coverage group is also configured to receive, from each other radio in the coverage group, a range message generated by each other radio. Based on the range message received from each other radio, each radio is configured to determine bi-directional connectivity between the receiving radio and the radios that sent the D-ARTS messages. The determined bi-directional connectivity status is between each radio and each of at least two other radios in the coverage group.

Abstract: A method and apparatus for confirming delivery of group data to a plurality of radio communication devices in a wireless communication system. The wireless communication system includes a plurality of radio communication devices in communication with a sender. In operation, the sender sends group data to the plurality of radio communication devices and further determines a call hang time sufficient to contain a dedicated acknowledgment slot for each of the plurality of radio communication devices. The sender reserves an acknowledgment slot in the determined call hang time for each radio communication device and further sends an acknowledgment polling signal to each radio communication device, where the acknowledgment polling signal identifies the respective acknowledgment slot that is reserved for each radio communication device to acknowledge receipt of the group data. The sender accordingly receives an acknowledgment from the radio communication devices during its respective reserved acknowledgment slot.