Motorola Corporation

Other

Kenneth J Zdunek

Michael D Sasuta

Richard A Comroe

Jaime Andres Borras

Garry C Hess

Daniel J Coombes

Michael D Kotzin

Gary W Grube

Arun Sobti

Eric R Schorman

Joseph Gerard Schultz

Walter J Rozanski, Jr

Robert W Furtaw

Charles Michael Jones

Stuart W Thro

Charles N Lynk

Eric F Ziolko

Jay R Krebs

Alfred B Wieczorek

Sewim F Ablay

John E Major

Terry K Mansfield

Timothy A Monahan-Mitchell

Richard S Bickham

Susan M Whitney

Ronald L Scheiderer

Philip A Bieri

Bruce D Heyman

Susan M Blackston

Gerald E Pioch

Eric Reed Schorman

The present invention is a system and method for detecting and locating the transmission of radio frequency signals from within a defined geographical area. The system uses statistical confidence limits to detect outliers caused by transmissions in the defined geographical area. The source of the transmission can then be located with triangulation.

Radio frequency signal transmission detector and locator

A radio system user (126) is alerted (129) as to the occurrence of a financial transaction by a customer (118). Data (122) is obtained from the customer (118) and used to identify a radio system user (126), who is authorized to conduct the financial transaction. A message, indicative of the financial transaction, is automatically provided to a radio system and broadcast (129) to the radio system user (126), thereby alerting the user (126) to the financial transaction.

Method of providing an alert of a financial transaction

A radio communication system including a control station and at least one remote station (20) is provided. The control station has a receiver for receiving radio signals, a transmitter for transmitting radio signals and a demodulator for measuring the frequency of the received signals. Responsive to a request for frequency measurement received from the receiver, the control station also has an error signal encoder to provide an error feedback signal containing the polarity and magnitude of the frequency difference for transmission by the transmitter. At least one remote station (20) has a receiver (25), a transmitter (26), a frequency controller (46), an encoder for encoding the request for frequency measurement and for actuating the transmitter (26) to transmit the request, and a decoder (34), responsive to the received error feedback signal for adjusting the frequency control.

Radio frequency error detection and correction system

A shared data/voice communication system wherein data traffic may be guaranteed priority at a set, but programmable, level of system capacity and wherein interference between such data and voice traffic is effectively minimized. The system operates on standardized channel access rules in the data mode, as well as requesting permission to operate in the voice mode, which if granted, effects a specific protocol to condition the system for voice traffic and manage the same during such pendency. Long and short timers are selectively activated depending upon whether the system is in the voice or data mode to minimize collisions of the system radio data terminals requesting channel access.

Shared data/voice communication system with programmable data priority

A trunked communication system wherein channel assignment information is provided to a requesting subscriber unit in a dual word format that includes separate and specific information regarding both a transmit frequency and a receive frequency. The transmit and receive frequency information is provided in a coded form, which can be decoded by the subscriber unit with reference to a table of information stored therein in conjunction with a simple algorithm.

Universal frequency assignment protocol for trunked radio systems

An improved communication system is disclosed wherein at least one reprogramming station is added to a communication system. The reprogramming station is constructed and arranged to communicate with the subscriber units thereby either reprogramming or regrouping them. The subscribing units receive the reprogramming command and acknowledge individually, altering a memory means until either reprogrammed back to the original state, or to another state. In another mode, the reprogramming station transmits a regrouping command wherein two or more groups are combined to form a super group.

Method for dynamically regrouping subscribers on a communications system

All subscribers operating within a communication system initially generate and transmit a random password and their ID code to the operation (control) center of a communication system. Thereafter, in a first embodiment, subscribers are commanded to modify (in a predetermined manner) and re-transmit their password and ID code either periodically or upon requesting access to the communication system. The modified password is retained as the current (authorized) password by both the subscriber and the system. In a second embodiment, subscribers are commanded to generate and transmit a new random password and their ID code to the system, which maintains a history of each subscriber's current and previous passwords. According to the invention, some of the subscribers having an unauthorized (duplicated) ID code may be inactive (off) when the subscriber is commanded to modify or generate a password. In this way, one of the subscribers having an unauthorized (duplicated) ID code will become out-of-sync with the system, and eventually transmit an unauthorized password. When the system receives an incorrect password for an out-of-sync subscriber, access to the communication system may be denied, and the subscribers that duplicate (or permit others to duplicate) ID codes may be identified.

Method and apparatus for controlling access to a communication system

A trunked communications system that accommodates encrypted secure communications. The system uses both non-encrypted message detectors and encrypted message detectors to assure that the trunked central control unit receives the signals it must receive in order to properly allocate and maintain channel assignments.

Secure trunked communications system

Disclosed is a method to dynamically allocate a number of data channels on a trunked radio system (100). The data activity is monitored during a predetermined time interval. If activity is above a predetermined maximum, an additional channel may be reserved for data use. Conversely, if data traffic is low, a data channel may be reallocated for voice message use. Moreover, should the amount of data traffic among the available data channels be unbalanced, the present method contemplates reassigning subscriber units (114 or 116) to the available data channels to balance the data traffic load, thereby providing superior access time and system performance.

Method for dynamically allocating data channels on a trunked

A trunked voice/data subscriber is provided that operates in either a voice mode, or one of three data modes. In a first data mode, the voice/data subscriber monitors the voice control channel to enable rapid participation in a voice call. In a second data mode, the subscriber monitors an assigned data channel until either commanded to change modes or until there has been no data activity for a predetermined time interval. Lastly, the subscriber may operate to remain in the last mode used so that, over time, the subscriber resides primarily in the mode predominately used. According to the invention, the voice/data subscriber must request a channel for each voice transmission. However, a data channel request need only be transmitted in no data channels are currently reallocated. If a data channel has been allocated, the subscriber may transmit at any time without first requesting access.

Subscriber unit for a trunked voice/data communication system

Selected regional trunking systems are equipped with telephone interconnect capability and provided with local computers (106), which communicate with a national hub computer (110). At each selected trunking system, several IDs are reserved as 'roaming IDs' to be temporarily assigned to roaming subscribers (112). When a subscriber determines that it has roamed into a new trunked system, it requests a roaming ID. A roaming ID is assigned and transmitted to the subscriber, which thereafter operates within the new trunked system using its roaming ID. The roaming assignment is also transmitted to the national hub computer (110) so that interconnect calls may be approximately properly forwarded. The roaming subscriber (112) continues to operate under the assigned roaming ID until it roams out of the range of the current system and into yet another trunked system. In this way, the subscribers may roam from system to system.

Trunked communication system with nationwide roaming capability

A trunked communication signalling method is provided by a unifying signalling protocol in which subscribers request communication channels using only their individual IDs encoded into a single ISWs. The central decodes the call request, extracts the requesting subscriber's individual ID, which is cross referenced to determine the subscriber's talk-group affiliation(s). If the requesting subscriber's affiliation(s) are not known, the central commands the subscriber to transmit its affiliation using dual ISW signalling. In another aspect of the present invention, each subscriber automatically informs the central of a change in talk-group affiliation, thereby providing continual affiliation updates. In this way, many thousand subscribers are afforded access to a single trunked system, and control channel traffic congestion is minimized.

Signalling method for establishing trunked communication

The present invention contemplates an improved dispatch trunked radio system which provides for individual subscriber to subscriber communication as well other enhanced trunking features. An expanded 'dual-word' signalling protocol provides an improvement over prior 'single word' signalling protocols by increasing the versatility of commands which may be communicated between the components of the trunked radio system. The 'dual-word' signalling protocol of the present invention remains compatible with prior 'single-word' subscriber units.

Dispatch trunked radio system

The system requires the use of the permanent ID of the requesting unit in every channel request made on a control channel before every transmission. The channel grant will include the ID along with the channel number and these may be recorded for possible later reference. A channel assignment is retained for a brief period after each transmission, allowing a conversation to be continued on the same channel without a break. Units can access the control channel with a channel request and be assigned a channel even while the dispatcher is using the voice channel. In the case of a need for communication with a larger group, a dispatcher can form a temporary 'patch' group of all involved units, with a temporary ID assigned to that group. A channel request from a member of the larger group must then include, not only the permanent ID of the requesting unit, but the temporary ID of the 'patch' group.

Growing community of inventors

Schaumburg, IL, United States of America

Kenneth J Zdunek