Motorola Solutions, Inc.

Yueh Ching Chung

David G Wiatrowski

Hun Weng Khoo

Dipendra M Chowdhary

John P Belmonte

Thomas B Bohn

Satyanarayan R Panpaliya

Teik Choon Teh

Badarinath Patibandla

Quan-Wen Du

Xiao-Yu Li

Yu-Yang Zheng

Chebron Padmanaba

In a direct mode two-way radio frequency communications system having a plurality of direct mode traffic channels, a first direct mode subscriber unit (DMSU) monitors a preconfigured direct mode control channel (DMCC), the DMCC being a channel that is monitored by all DMSUs that are idle in the system, and which is time divided into slots including traffic channel status slots (TCSSs), each TCSS associated with another physical direct mode traffic channel (DMTC) in the communication system. Responsive to detecting a request to initiate a new call, the DMSU selects a first DMTC on which to transmit the call, transmits during the next TCSS of the DMCC associated with the selected DMTC a header indicating the first DMSU's intention to transmit a new call on the selected DMTC, and subsequently switches to the selected DMTC and transmits the new call.

Method and device for reusing channel frequencies in direct mode

A radio receives audio information on a first traffic channel in a radio frequency (RF) site. The radio receives, on the first traffic channel, an announcement of alternative traffic channels on which the audio information is also transmitted in adjacent RF sites. The radio determines signal strength indicators for the alternative traffic channels in the adjacent RF sites while continuing to receive the audio information on the first traffic channel. The radio determines that a signal strength associated with the first traffic channel is below a first threshold. Based on the determination and as a function of the scanning, the radio roams to a second traffic channel, selected from the alternative traffic channels, in an adjacent RF site where a signal strength associated with the second traffic channel is above a second threshold. The radio receives the audio information via the second traffic channel.

Apparatus and method for enabling efficient handover of a receiving radio between radio frequency sites

A method for enhanced data throughput on a windowed revert repeater channel in a radio communication system includes requesting, by a subscriber unit and via a control channel of the radio communication system, a window in which to transmit data updates on the windowed revert repeater channel of the radio communication system; receiving, by the subscriber unit and via the control channel, an assigned window on the windowed revert repeater channel for the data updates; monitoring, by the subscriber unit, the control channel repeater and determining a timing of the windowed revert repeater channel based on the monitoring; and reverting to the windowed revert repeater channel based on the timing and the assigned window, and transmitting the data updates during the assigned window. A subscriber unit and radio communication system are also disclosed.

Enhanced location data throughput on a windowed data channel in a radio communication system

A radio affiliates, via a first channel, with at least one talk group the radio is interested in receiving calls from, sends a request to transmit location information on a separate revert channel, and receives a first grant time period to transmit location information on a particular revert channel. The radio moves at substantially the first grant time period, away from the first channel to the revert channel to transmit location information or request a second grant time period on the revert channel, receives an announcement on the revert channel during the first grant time period that a call of interest associated with the at least one talk group started while the radio was on the revert channel, determines an assigned traffic channel for the call of interest, and switches from the revert channel to the assigned traffic channel in order to receive the call of interest.

Method and apparatus for informing a radio of a group-call started while the radio was away from a control channel

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.

Method and apparatus for wirelessly transacting simultaneous voice and data on adjacent timeslots

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.

Full duplex direct mode individual and group calling using adjacent time slots in a TDMA system

A method for enabling full duplex individual calls in repeater mode between two subscriber units (SUs) in a N:1 slotting ratio time division multiple access (TDMA) radio system includes receiving a request for a full duplex individual call from a first SU identifying a second SU as a target of the call. Determining to grant the request and subsequently assigning a first time slot of the N time slots on a first single frequency for one of inbound and outbound transmissions for the call between an assigned second repeater and the first SU and a second time slot on the first single frequency for the other of inbound and outbound transmissions for the call between the assigned second repeater and the first SU. Further, a grant message is transmitted to the first SU indicating the assigned first single frequency and assigned first and second time slots.

Full duplex individual call via linked single frequency repeaters

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.

Method and apparatus for automatically determining a communication range status of communicating radios

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.

Method and apparatus for sending a channel timing message in a digital mobile radio system

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.

Method and device for detecting a channel

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.

Method and apparatus for tracking a channel timing channel message and supporting channel scanning in a digital mobile radio system

A method for diffusing channel timing among a plurality of subscriber units operating in TDMA Direct Mode, wherein the method includes: receiving, from a second one of the subscriber units operating in the TDMA Direct Mode, a first message; determining first channel timing from the received message; determining whether the received first channel timing is correct, wherein the determining is based at least on comparing a generation of the first subscriber unit with a generation of the second subscriber unit; when the received first channel timing is correct, starting a random delay; upon expiration of the random delay, transmitting a first forced propagation message to propagate the first channel timing to at least a third one of the subscriber units operating in the TDMA Direct Mode and having a higher generation than the generations of the first and the second subscriber units.

Methods and apparatus for diffusing channel timing among subscriber units in TDMA direct mode

To perform a channel inspection, a wireless communication device: monitors a common announcement channel (CACH) until detecting that a first set of identified parameters associated with a signal on a first channel matches a second set of known parameters for the first channel; performs an inspection on the first channel to determine whether the signal is of interest; and when the signal is not of interest, marks the first channel to prevent another inspection from being performed on the first channel until after the channel mark is removed. The communication device then leaves the first channel and continues to monitor the CACH for a change in the first set of identified parameters or an indication of an idle first channel, wherein the communication device removes the channel mark on the first channel.

Method and device for channel inspection in a communication system

To perform channel inspection, a wireless communication device conducts a full inspection on a first channel carrying a first signal that includes: determining a location of a first synchronization message; and determining whether the first signal is of interest. Upon determining that the first signal is not of interest, the first channel is marked, wherein the marking includes remembering the location of the first synchronization message. The device leaves the first channel and determines an expected location of a second synchronization message on the first channel based on the location of the first synchronization message. Upon returning to the first channel which carries a second signal, the communication device conduct a partial inspection that includes: detecting whether the second synchronization message is present at the expected location, wherein the presence of the second synchronization message indicates that the second signal is not of interest.

A device detects a first signal on a channel that is one of a plurality of channels arranged in a first order on a list, with each channel being associated with a different site in a multi-site communication system. Upon detecting the first signal, the device attempts to measure and record signal strength of a signal at each channel on the list based on the first order beginning with the detected first signal, and selects as a home site the site associated with the channel having the signal with the highest recorded signal strength. The device rearranges the channels on the list into a second order based on the recorded signal strengths with the home site channel at the top. If necessary, the radio attempts to awaken its repeaters one after another based on the second order until a repeater is found to transmit a signal.

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Georgetown, Malaysia

Yueh Ching Chung