Cellular telephone data communication system and method

Abstract

The cellular telephone data communication system and method involves the use of a mobile data processing interface and a cooperating static data processing interface to effectively transmit data over a cellular telephone system. Each data processing interface includes a processor which operates in the transmitting mode to add an error control correction data format to data received from an external data source. The data is divided into packets and provided to a modem which is uniquely operated to eliminate the action of the modem scramble system and to remain active in spite of a carrier signal loss. The modem is deactivated or disconnected by a disconnect signal from the processor, and when carrier signal loss occurs, this disconnect signal is provided only after the lapse of a delay period without the resumption of the carrier signal. The error control correction data format causes a receiver to evaluate the received data for error and to retransmit an acknowledgment signal for each acceptable packet of received data. In the absence of an acknowledgment signal, the processor will again provide a data packet to the modem for retransmission. Also, the processor will determine the frequency of error in the received data from the acknowledgment signals and subsequently adjust the data packet size in accordance with this error frequency.

1. A method for transmitting data from a transmitting station over a cellular telephone system to a receiving station by means of a modem connected to said cellular telephone system which is operative in an activated state to modulate a carrier signal for said cellular telephone system with a data signal, said method including the steps of placing said modem in the activated state, providing a data signal to said activated modem, maintaining said modem in the activated state for a predetermined time period after a loss of said carrier signal before permitting said modem to deactivate, and causing said modem to remain in said activated state after the loss of said carrier signal if said carrier signal resumes within said predetermined time period. 
     
     
       2. The method of  claim 1  which includes adding an error control correction data format to said data signal before providing said data signal to said mode. 
     
     
       3. The method of  claim 1  which includes repetitively providing a unique data byte to said modem during a break in said data signal. 
     
     
       4. The method of  claim 2  wherein the addition of said error control correction format involves dividing data to be transmitted into a plurality of data packet, each data packet including a plurality of data words, the number of data words in a data packet determining the size of the data packet, providing said data signal to said modem for transmission to said receiving station, examining the data words in each received data packet at the receiving station for error and determining which data words are acceptable, transmitting an acknowledgment signal to the transmitting station for each acceptable data word, determining from the transmitted acknowledgment signals which data packets were received with unacceptable errors and retransmitting said unacceptable data packets, and determining the frequency of error in said received data packets from said acknowledgment signals and adjusting the size of subsequent data packets to be transmitted in accordance with said error frequency. 
     
     
       5. The method of  claim 4  which includes decreasing the size of subsequent data packets to be transmitted as the frequency of error in received data packets increases and increasing the packet size of subsequent data packets to be transmitted as the frequency of error in received data packets decreases. 
     
     
       6. The method of  claim 4  which includes sensing a complete loss of said carrier signal for a predetermined period at said transmitting station and initiating said predetermined time period in response to said loss to maintain said modem in the activated state. 
     
     
       7. The method of  claim 6  which includes causing said modem to disconnect and terminate transmission to said receiving station of all data packets if the signal is not resumed within said predetermined time period. 
     
     
       8. The method of  claim 7  which includes operating said modem without a scrambler polynomial and continuously changing said data signal provided to said modem for modem synchronization. 
     
     
       9. The method of  claim 8  which includes repetitively providing a unique data byte to said modem during a break in said data signal to prevent the modem from entering a static condition. 
     
     
       10. A method for transmitting data between a transmitting station and a receiving station which includes dividing data to be transmitted into a plurality of data packets, each data packet including a plurality of data words, the number of data words in a data packet determining the size of the data packet, transmitting said data packets to the receiving station, examining the data words in each received data packet for error and determining which data words are acceptable, transmitting an acknowledgment signal to the transmitting station for each acceptable data word, determining from the transmitted acknowledgment signals which data packers were received with unacceptable errors and retransmitting said unacceptable data packets, and determining the frequency of error in said received data packets from said acknowledgment signals and adjusting the size of subsequent data packets to be transmitted in accordance with said error frequency. 
     
     
       11. The method of  claim 10  which includes decreasing the size of subsequent data packets to be transmitted as the frequency of error in received data packets increases and increasing the packet size of subsequent data packets to be transmitted as the frequency of error in received data packets decrease. 
     
     
       12. A signal processing interface for communicating data from a data source over a cellular telephone system to a receiving means via a cellular telephone radio carrier signal comprising processing means connected to receive data from said data source, said processing means operating to form said data into a data signal format to be transmitted as a data signal, the data signal format including blocks of data, at least one acknowledgment signal to be retransmitted by said receiving means back to said processing means upon receipt of each of said data blocks, cellular telephone transmission means operative upon receipt of said data signal format to transmit said data signal to said receiving means, and modem means connected to said signal processing means and said cellular telephone transmission means and operative to receive said data signal containing said data signal format from said processing means and to provide said data signal for transmission to said cellular telephone transmission means, said modem means being operative to disconnect from said cellular telephone transmission means in response to a disconnect signal and inoperative to disconnect in response to a loss of said cellular telephone radio carrier signal, said processing means operating to provide a disconnect signal to said modem means when a delay period subsequent to a loss of said cellular telephone radio carrier signal has elapsed without the resumption of said cellular telephone radio carrier signal. 
     
     
       13. The signal processing interface of  claim 12  wherein said modem means operates without a scrambler polynomial, said processing means operating to continuously change said data signal to provide synchronization for said modem means. 
     
     
       14. The signal processing interface of  claim 13  wherein said processing means operates in response to a break in said data to repetitively provide a unique data byte to said modem means for the duration of said break in the data. 
     
     
       15. A cellular telephone data communication system for communicating data from a data source over a cellular telephone system having a mobile transceiver unit operative to transmit and receive cellular telephone signals and a plurality of fixed transceiver units connected to transmit signals over a conventional telephone line system comprising a mobile signal processing interface means connected to said mobile transceiver unit and operative to communicate data from a data source to said mobile transceiver unit for transmission via a cellular telephone radio carrier signal or to receive a transmitted data signal from said mobile transceiver unit, and a static signal processing interface means connected to said conventional telephone line system and operative to communicate data from a data source over said conventional telephone line system to one of said fixed transceiver units for transmission via a cellular telephone radio carrier signal to said mobile unit or to receive a transmitted data signal via said conventional telephone line system, each said mobile signal processing interface means and static signal processing interface means being operative in a transmitting or receiving mode while the other operates in the opposite mode and each including signal processing and control means connected to receive data from a respective data source in the transmitting mode, said signal processing and control means also being operative in the receiving mode to receive a data signal from the associated mobile transceiver unit or associated conventional telephone line system, and modem means connected to said signal processing and control means, the signal processing and control means of the mobile or static signal processing interface means operating in the transmitting mode being operative to receive data from the associated data source and to form said data into a data signal format to be transmitted as a data signal to the modem means connected thereto, said modem means being operative to disconnect in response to a disconnect control signal and inoperative to disconnect in response to a loss of said cellular telephone radio carrier signal, the signal processing and control means operating to provide a disconnect control signal to the modem means connected thereto when a delay period subsequent to a loss of said radio carrier signal has elapsed without the resumption of said telephone radio carrier signal. 
     
     
       16. The cellular telephone data communication system of  claim 15  wherein the data signal format is formed by the signal processing and control means for the mobile or static signal processing interface means operating in the transmitting mode by dividing data to be transmitted into a plurality of data packets, each data packet including a plurality of data words, the number of data words in a data packet determining the size of the data packet, the signal processing and control means for the mobile or static signal processing interface means operating in the receiving mode being operative to receive and examine the data words in each transmitted data packet for error to determine which data words are acceptable and to transmit an acknowledgement signal for each acceptable data word to the transmitting mobile or static signal processing interface means, the signal processing and control means for the transmitting mobile or static signal processing interface means operating to receive and determine the frequency of error in said received data packets from said acknowlegment signals and to adjust the size of subsequent data packets to be transmitted in accordance with said error frequencey. 
     
     
       17. The cellular telephone data communication system of  claim 16  wherein the signal processing and control means for the transmitting mobile or static signal processing interface means operates to control the size of subsequent data packets inversely to the error frequency detected thereby. 
     
     
       18. A data processing interface for operation in a transmitting mode for transmitting data from a data source over a cellular telephone system to a receiving means via a cellular telephone radio carrier signal comprising processing and control means connected to receive data from said data source, said processing and control means operating to form said data into a data signal format to be transmitted as a data signal, said data signal format including a plurality of data packets, each said data packet including a number of data and control words, the number of words in a data packet determining the size of the data packet, each said data packet including an error control correction data format having at least one acknowledgement section, the acknowledgement section adapted to be retransmitted by said receiving means as an acknowledgment signal when an acceptable data packet is received by said receiving means, and modem means connected to said processing and control means to receive said data signal therfrom, said modem means being operable to modulate said cellular telephone radio carrier signal with said data signal and to provide said modulated signal to said cellular telephone system, said modem means receiving the acknowledgment signals transmitted by the receiving means and operating to provide such acknowledgment signals to said processing and control means, the processing and control means determining from said acknowledgment signals the frequency of error in the received data packets and adjusting the size of subsequent data packets in the data signal in accordance with said error frequency. 
     
     
       19. The data processing interface of  claim 18  wherein said processing and control means determines from the acknowledgment signals which data packets were received with unacceptable errors and provides said data packets to said modem means for retransmission by said cellular telephone system. 
     
     
       20. The data processing interface of  claim 19  wherein said modem means operates without a scrambler polynomial, said processing and control means operating to continuously change the data signal to provide synchronization for said modem means. 
     
     
       21. The data processing interface of  claim 19  wherein said modem means operates without a scrambler polynomial, said processing and control means operating in response to a break in the data from said data source to repetitively provide a unique data byte to said modem means for the duration of said break in the data. 
     
     
       22. The data processing interface of  claim 19  wherein said modem means is operative to disconnect from said cellular telephone system in response to a disconnect signal and inoperative to disconnect in response to a loss of a cellular telephone radio carrier signal, said processing and control means operating to provide a disconnect signal to said modem means when a delay period subsequent to a loss of said cellular radio carrier signal has elapsed without the resumption of said cellular telephone radio carrier signal. 
     
     
       23. The data processing interface of  claim 22  which is operative in a receiving mode to receive a data signal transmitted by said cellular telephone system, said modem means receiving the data signal from said cellular telephone system and providing said data signal to said processing and control means, the processing and control means operating to examine the data words in each received data packet for error to identify acceptable data words and providing an acknowledgment signal to said cellular telephone system for each acceptable data word, the processing and control means operating to remove the error control correction data format from said data section. 
     
     
       24. The data processing interface of  claim 23  wherein said modem means operates without a scrambler polynomial, said processing and control means operating to continuously change said data signal to provide synchronization for said modem means. 
     
     
       25. The data processing interface of  claim 24  wherein said processing and control means operates in response to a break in the data from said data source to repetitively provide a unique data byte to said modem means for the duration of the break in said data. 
     
     
       26. A vehicular wireless voice and data communication system, comprising
   a. a cellular telephone transceiver mounted within a vehicle for accessing a cellular telephone network operating in accordance with a standardized cellular network operating protocol to send and receive voice and data signals over a cellular telephone network, the cellular telephone transceiver including circuitry specifically adapted to cause the cellular telephone transceiver to respond to cellular transceiver control signals formatted in accordance with a standardized cellular network operating protocol specific to the cellular telephone network;        b. a computing device, including a memory sufficient to allow the computing device to be used in the manner of a portable computer, operable to generate transceiver control signals to control communication over the cellular wireless network from within the vehicle, the control signals being formatted in accordance with a standardized computer data communication protocol that differs from the standardized cellular network operating protocol implemented by the cellular telephone transceiver, and        c. circuitry for connecting the cellular telephone transceiver and the computing device to allow transceiver control signals, generated by the computing device and formatted in accordance with the standardized computer data communication protocol, to be implemented by the cellular telephone transceiver using the standardized cellular network operating protocol.     
     
     
       27. A cellular telephone data transmission apparatus, comprising
   a. a cellular telephone transceiver for accessing a cellular wireless network for sending and receiving voice and data signals over a cellular telephone network, the cellular telephone transceiver operating in different modes including a call placement mode and a data transceiving mode;        b. a computing device including a memory sufficient to allow the computer device to operate as a portable computer, the computing device operating to send and receive data over the cellular telephone network when the cellular transceiver is operating in the data transceiving mode, and        c. a circuit connected with the cellular telephone transceiver and the computing device for determining when the cellular telephone transceiver is operating in the data transceiving mode and causing the computing device to send and receive data over the cellular telephone network only when the transceiver is operating in the data transceiving mode.     
     
     
       28. A combined portable computing and cellular voice and data communication device, comprising
   a. a cellular telephone transceiver for accessing a cellular telephone network for either voice or data communication, the cellular transceiver operating in accordance with a standardized cellular network operating protocol to send and receive voice and data signals over a cellular telephone network, the cellular telephone transceiver including circuitry specifically adapted to cause the cellular telephone transceiver to respond to cellular transceiver control signals formatted in accordance with the standardized cellular network operating protocol specific to the cellular telephone network;        b. a portable computer operating to generate transceiver control signals to control communication over the cellular telephone network, the control signals being formatted in accordance with a standardized computer data communication protocol that differs from the standardized cellular network operating protocol implemented by the cellular telephone transceiver, the portable computer including computer memory sufficient to allow for portable computer uses other than generating cellular telephone transceiver control signals; and        c. circuitry for connecting the cellular telephone transceiver and the portable computer to allow transceiver control signals, generated by the portable computer and formatted in accordance with the standardized computer data communication protocol, to be implemented by the cellular telephone transceiver using the standardized cellular network operating protocol,        whereby the portable computer, in one mode, may be used to originate control signals to control the operation of the transceiver to control the transceiver to allow user data processed by the portable computer to be sent over the cellular network and to allow user data to be received by the portable computer for subsequent processing by the portable computer and, in another mode, may be used for data processing functions other than control of the cellular telephone transceiver.     
     
     
       29. A system for transferring data between a mobile station and at least one fixed station over a cellular telephone network comprising:
   a vehicular mobile radio telephone network access device capable of bidirectionally communicating voice and data between the mobile station and a fixed station;        a computer in said vehicle, the computer providing and receiving data signals;        an interface circuit connected between the computer and the vehicular mobile radio telephone network access device for transmitting data signals to and from the vehicular mobile radio telephone network access device, said interface circuit providing lines for connection to the vehicular mobile radio telephone network access device, said lines including:      a data transmit line for transmitting data signals received from the computer to the vehicular mobile radio telephone network access device;        a data receive line for transmitting data signals from the vehicular mobile radio telephone network access device to the computer; and        plural control lines for providing at least one digital control signal, including a dial control signal, to the vehicular mobile radio telephone network access device to control the operation of the device;          dialing circuit in said interface circuit connected to at least one of the control lines for allowing the computer to cause the vehicular mobile radio telephone network access device to set up a cellular call; and        a program residing in said computer, said program causing said dialing means to set up the cellular call over the radio telephone network.     
     
     
       30. The cellular telephone data communication system of  claim 29 , further including a modem operably connected to the computer for modulating data signals received from the computer for transmission over the vehicular mobile radio telephone network access device and for demodulating data signals received from the vehicular mobile radio telephone network access device. 
     
     
       31. The cellular telephone data communication system of  claim 29  wherein said interface circuit inserts error correction bits into said data signal. 
     
     
       32. The cellular telephone data communication system of  claim 29  wherein said data signal is packetized. 
     
     
       33. The cellular telephone data communication system of  claim 32  wherein said packetized data signal comprises packets of variable length, said packet length adjusted according to signal quality. 
     
     
       34. The cellular telephone data communication system of  claim 29  wherein said computer, said interface device and said vehicular mobile radio telephone network access device is powered by a vehicle battery. 
     
     
       35. A cellular computer data transmission system disposed in a vehicle for communicating bidirectional computer data to and from a fixed location over a cellular telephone network, the system comprising a radio transceiver having a digital controller for generating control signals including network access signals for controlling the operation of the radio transceiver for communicating on the cellular network, a computer separate from the digital controller, the computer operating to control access to the cellular telephone network and for originating and receiving data and an interface for providing a data path between the computer and the radio transceiver, the interface containing a modem for modulating and demodulating data signals for transmission on the cellular telephone network, the interface including parallel signal lines between the computer and the radio transceiver including at least a transmit signal line, a receive signal line, and a control line, whereby data are communicated between the computer in the vehicle and a fixed station over the cellular network. 
     
     
       36. The cellular computer data transmission system of  claim 35  wherein the data contain error correcting bits. 
     
     
       37. The cellular computer data transmission system of  claim 35  wherein the data are packetized. 
     
     
       38. The cellular computer data transmission system of  claim 37  wherein the packetized data comprise packets of variable length, the length adjusted according to error rate. 
     
     
       39. A vehicle mobile computer communications system comprising:
   a radio transceiver means for communicating over a cellular telephone network;        a digital controller for generating control signals including network access signals for controlling the operation of the radio transceiver;        a computer means separate from the digital controller for running at least one application program providing and receiving data;        an interface means disposed between said computer means and said radio transceiver means, said interface means containing a modem and parallel signal lines including at least a transmit line, a receive line and plurality of control lines;        said interface means transferring data from said application program in said computer means to said radio transceiver means for transmission over said cellular telephone network and transferring received data from said radio transceiver means to said application in said computer means.     
     
     
       40. The vehicle mobile computer communications system of  claim 39  wherein said computer means inserts error correction bits into said data. 
     
     
       41. The vehicle mobile computer communications system of  claim 39  further comprising dial means contained in said interface means for causing said transceiver means to place a call over said cellular communications network. 
     
     
       42. The vehicle mobile computer communications system of  claim 41  wherein said application program causes said dial means to automatically place a call over said cellular communications network. 
     
     
       43. A cellular telephone data communication system for communicating data over a cellular telephone system between a fixed station and a mobile station comprising:
   at least one mobile radio transceiver having a digital controller for generating control signals including network access signals for controlling the operation of the radio transceiver, said mobile radio transceiver being coupled to a computer separate from said digital controller, said mobile radio transceiver capable of bidirectionally communicating voice and data between said mobile station and said fixed station, said computer being capable of executing at least one application program;        said application program causing said mobile radio transceiver to establish communication with said fixed station upon the occurrence of a predetermined event, said application program then sending data to said fixed station.     
     
     
       44. The cellular telephone data communication system of  claim 43  further comprising an interface disposed between said radio transceiver and the computer, the interface allowing the computer to control said radio transceiver. 
     
     
       45. The cellular telephone data communication system of  claim 44  wherein said interface inserts error correction bits into said data. 
     
     
       46. The cellular telephone data communication system of  claim 43  wherein said data is packetized.