Paging system with multiple frequencies and multiple protocols

• US 5,170,487 A
• Filed: 02/28/1991
• Issued: 12/08/1992
• Est. Priority Date: 01/19/1989
• Status: Expired due to Term

• Current Assignee: Protocol-ip.com, LLC, Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Corporation (Seiko Group), Seiko Epson Corporation (Seiko Group)
• Inventors: Peek, William H.
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US07/662,097
• Time in Patent Office: 649 Days
• Field of Search: 455/33, 455/45, 455/101-103, 455/132-133, 340/825.44, 340/825.73, 340/825.04, 379/57
• US Class Current: 455/45
• CPC Class Codes: G08B 3/1016 using wireless transmission calling systems using transmission by inductive loop H04B5/00
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 88/022 Selective call receivers
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention provides a pager system which integrates a plurality of transmitters which operate at different frequencies. Some of the transmitters transmit paging messages using FM subcarrier signals (termed FM-SCA signals) and some transmit messages using a modulated carrier (termed RCC signals). The receiver includes two front ends. One front end receives and demodulates FM-SCA signals and one front end receives and demodulates RCC signals. Each paging message is transmitted on both FM-SCA transmitters and on RCC transmitters. The signals on each of the transmitters are slightly off set in time. When an assigned time slot occurs, one receiver turns on and attempts to receive a message, if it does not receive an appropriate signal, it tunes to another station that is in a stored list of stations. If the next station has an RCC flag associated therewith the RCC receiver rather than the FM-SCA receiver is operated. The entire process is controlled by a microprocessor which is a part of the system.

Claims

1. A pager system which integrates a plurality of transmitters which transmit the same paging message of times, said transmissions having a time offset from each other and including a flag indicating the protocol being used:

a first plurality of transmitters which transmit said messages on FM subcarrier signals,

a second plurality of transmitters which transmit said messages as modulated RCC signals,

a receiver which includes,

a first front end that can receive messages transmitted on an FM subcarrier using a first protocol,

a second front end that can receive messages transmitted as a modulated carrier RCC signals using a second protocol,

decoder means for decoding both FM subcarrier and RCC protocols and for extracting the message received using either FM subcarrier or RCC protocols,

logic means for controlling which of said front ends is operative at any particular time and for controlling the frequency which the system receives at any particular time, said logic means including means to normally maintain one of said front ends active and for switching to said other front end if no signal is received on said active front end, and means for switching said decoder means between FM subcarrier and RCC protocols in response to said flag in the data received by the active receiver.

3. The system recited in claim 1 wherein said messages are transmitted utilizing a time slot protocol according to which each receiver is only activated during an assigned time slot.

5. The system recited in claim 1 wherein said logic means comprises a microprocessor.

2. A paging receiver for operation with a system which integrates a plurality of transmitters which transmit the same paging message in time offset fashion, some of said plurality of transmitters, transmitting said messages using a first protocol on FM subcarrier signals and some of said plurality of transmitters, transmitting said messages using a second protocol as modulated RCC signals, at least one of said protocols including a flag indicating the type of protocol,

said receiver including,

a first front end that can receive messages transmitted on an FM subcarrier,

a second front end that can receiver messages transmitted as a modulated carrier RCC signals,

logic means for controlling which of said front ends is operative and for controlling the frequency and protocol which the system receives at any particular time, said logic means switching to a different front end when no signals are received by the front end active at a particular time, said logic means being responsive to said flag to switch between protocols,

decoder means for decoding the protocol and extracting the message received on the particular frequency being received at any particular time.

4. The paging receiver recited in claim 2 wherein said messages are transmitted utilizing a time slot protocol according to which each receiver is only activated during an assigned time slot.

6. The paging receiver recited in claim 2 wherein said logic means comprises a microprocessor.

7. A paging receiver for operation with a system which integrates a plurality of transmitters each operating at a different frequency, which transmit the same paging message in time offset fashion, some of said plurality of transmitters transmitting said messages on FM subcarrier signals using a first protocol and some of said plurality of transmitters transmitting said messages as modulated RCC signals using a second protocol, at least one of said protocols including a flag indicating the type of protocol,

said receiver including,

a front end that can receive messages transmitted on both an FM subcarrier and modulated RCC signals.

decoder means for decoding the protocol and extracting the message received on the particular frequency being received at any particular time,

logic means for controlling said front end and for controlling the frequency which the system receives at any particular time, said logic means including means for switching said front end to a different frequency if no message signals are received on the frequency active at a particular time, and means for switching said decoder means to a different protocol in response to said flag.