High data rate simulcast communication system

• US 4,968,966 A
• Filed: 10/23/1989
• Issued: 11/06/1990
• Est. Priority Date: 10/13/1988
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Steel, legal representative, Lynne A., Jasinski, Leon, Steel, deceased, Francis R.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Pudpud, Eric O.
• Application Number:
  US07/425,662
• Time in Patent Office: 379 Days
• Field of Search: 340/311.1, 340/825.44, 340/825.47, 340/825.49, 340/825.52, 379/56, 379/57, 379/58, 379/69, 379/60, 455/33, 455/34, 455/31, 370/79, 370/84
• US Class Current: 340/7.22
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
• CPC Class Codes: H04W 84/022 One-way selective calling networks, e.g. wide area paging
• CPC Class Codes: H04W 88/185 Selective call encoders for paging networks, e.g. paging centre devices

Abstract

A system for transmitting long text messages includes a plurality of transmission cells defining different geographical areas, each having a transmitter for simulcast address transmission at a first data bit rate and for transmitting the address and a message at a second data bit rate higher than the first data bit rate. A paging transceiver generates and transmits an acknowledgment signal in response to receiving a transmitted address at the first data bit rate. Receivers located within each of the transmission cells receive the transmitted acknowledgment signal. An apparatus responsive to the received acknowledgment signal identifies the transmission cell in which the paging transceiver is located effecting the selection of the transmitter in the transmission cell in which the paging transceiver is located to transmit the address and message at the second data bit rate higher than the first data bit rate.

Claims

1. A method for transmitting a long text message to a paging transceiver in a system comprising a plurality of transmission cells defining different geographical areas, each transmission cell having a transmitter for transmitting an address and the message, and a receiver for receiving an acknowledgement signal generated by the paging transceiver, said method comprising the steps of:

transmitting the address at a first data bit rate, the address identifying the paging transceiver, the address being simulcast from transmitters located within each of a plurality of transmission cells;

transmitting an acknowledgement signal from the paging transceiver in response to having received the address;

receiving the acknowledgement signal by two or more receivers located within each of the plurality of transmission cells;

identifying the transmission cells of the receivers receiving the acknowledgement signal for locating the paging transceiver; and

selecting the transmitter in the transmission cell in which the paging transceiver is located, and at least one additional transmitter in a transmission cell adjacent to the transmission cell in which the paging transceiver is located, for simulcast transmitting the address and the message at a second data bit rate higher than the first data bit rate.

2. The method according to claim 1 wherein said plurality of transmission cells further have a link transmitter and a link receiver, said step of identifying comprising the steps of:

deriving information from the acknowledgement signal received in each of the plurality of transmission cells;

transmitting the information derived in each transmission cell from the link transmitter to a predetermined link receiver; and

correlating the information received at the predetermined link receiver to identify the transmission cell in which the paging transceiver is located and to identify at least one additional transmission cell adjacent the transmission cell in which the paging transceiver is located.

3. The method according to claim 1 further comprising the steps of:

formatting the address and the message with information identifying the transmission cell in which the paging transceiver is located and the at least one additional transmission cell adjacent the transmission cell in which the paging transceiver is located;

transmitting the formatted information to the link receivers located in each of the plurality of transmission cells;

accepting the formatted information at the transmission cell in which the paging transceiver is located and the at least one additional transmission cell adjacent the transmission cell in which the paging transceiver is located; and

transmitting the address and the message from the transmitter in the transmission cell in which the paging transceiver is located and from the at least one additional transmission cell adjacent the transmission cell in which the paging transceiver is located.

4. A system for transmitting long text messages, said system comprising:

a plurality of transmission cells defining different geographical areas, each having a transmitter for simulcast transmission of an address at a first data bit rate, and further for transmitting the address and a message at a second data bit rate higher than the first data bit rate;

a paging transceiver, having means for generating and transmitting an acknowledgement signal in response to receiving the transmitted address at the first data bit rate;

a receiver, located within each of said plurality of transmission cells, for receiving the transmitted acknowledgement signal;

identifying means, responsive to the received acknowledgement signal in each of said plurality of transmission cells, for identifying the transmission cell in which said paging transceiver is located and at least one additional transmission cell adjacent to said transmission cell in which said paging transceiver is located; and

selecting means, responsive to said identifying means, for selecting said transmitter in the transmission cell in which said paging transceiver is located and said transmitter in the additional transmission cell adjacent the transmission cell in which said paging transceiver is located, for simulcast transmitting the address and the message at the second data bit rate higher than the first data bit rate.

5. The system according to claim 4 wherein said first data bit rate for transmitting the address is 512 to 1200 bits per second.

6. The system according to claim 4 wherein said data bit rate for transmitting the address and message is 2400 to 4800 bits per second.

7. The system according to claim 4 wherein said identifying means comprising:

a signal strength indicator, responsive to the received acknowledgment signal in each of said plurality of transmission cells, for generating signal strength indication signal;

timing means, for generating timing signals in each of said plurality of transmission cells; and

a phase comparator, coupled to said timing means and to said receiver in each of said transmission cells, for comparing the timing signal and the received acknowledgement signal and for generating a time of reception signal in each of said transmission cells in response thereto;

link transmitters, located within each of said plurality of transmission cells, for transmitting the signal strength indication signal and the time of reception signal in each of said plurality of transmission cells; and

a predetermined link receiver, for receiving the signal strength indication signals and the time of reception signals from each of the plurality of transmission cells; and

a controller, responsive to the received signal strength indication signals and to the time of reception signals, for identifying the transmission cell in which said paging transceiver is located, and for identifying at least one additional transmission cell adjacent to the transmission cell in which said paging transceiver is located.

8. The system according to claim 4, wherein said selecting means comprising:

a predetermined link transmitter for transmitting the address, the message and information identifying said transmission cell in which said paging transceiver is located;

link receivers, for receiving the address, the message and the information identifying the transmission cell in which the paging transceiver is located; and

a controller, coupled to said link receiver, for individually accepting the information identifying the transmission cell in which said paging transceiver is located and for individually selecting said transmitter for transmitting the address and the message information in the transmission cell in which said paging transceiver is located, and said additional transmitter in the transmission cell adjacent the transmission cell in which said paging transceiver is located.

9. The system according to claim 7, wherein said selecting means further comprising encoding means, coupled to said signal strength indicator and to said phase comparator, for encoding the signal strength indication signals and the time of reception signals for transmission.