Two-way paging system and apparatus

• US 6,088,593 A
• Filed: 12/04/1998
• Issued: 07/11/2000
• Est. Priority Date: 01/11/1994
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson), Telefonaktiebolaget LM Ericsson
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US09/204,353
• Time in Patent Office: 585 Days
• Field of Search: 455/456, 455/457, 455/38.1, 455/31.3, 455/32.1, 455/561, 455/562, 455/67.1, 455/272, 455/12.1, 455/13.1, 455/67.6, 340/825.44, 340/311.1, 342/450, 342/463
• US Class Current: 455/456.1
• CPC Class Codes: G08B 3/1008 Personal calling arrangements or devices, i.e. paging systems selective calling systems and call receivers H04W84/00, H04W68/00
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2001/0098 Unequal error protection
• CPC Class Codes: H04L 25/03331 Arrangements for the joint estimation of multiple sequences
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 84/025 with acknowledge back capability
• CPC Class Codes: H04W 88/022 Selective call receivers
• CPC Class Codes: H04W 88/185 : Selective call encoders for paging networks, e.g. paging centre devices

Abstract

Paging systems typically include a network of ground stations or orbiting satellites equipped with transmitters and antennas for transmitting paging messages to small, battery-operated paging receivers that are worn about the person, known as pagers. Conventional pagers are receive-only devices and the network receives no confirmation that paging has been successful. The present invention includes the provision of two-way pagers that contain a transmitter for transmitting an acknowledgment confirming reception of a paging message, and a network of receiving stations able to receive said acknowledgments. The network makes use of advanced phased-array antenna signal processing techniques to render the return link operable with much less transmitter power in the portable unit than employed by the base station.

Claims

1. A paging network capable of transmitting short messages to and receiving short replies from portable paging units comprising:

a control site having means for controlling transmitter and receiver sites and sending information thereto and receiving information therefrom;

at least one transmitter site for transmitting short messages addressed to individual paging units;

at least two receiving sites each including;

plural antennas connected to respective receive channel signal processing units which convert received signals to corresponding sequences of complex numbers;

a synchronization mechanism for receiving a synchronization indication from said control site to control said receive channel processing unit and converting activity in time relation to said transmitter site'"'"'s transmissions;

memory means for storing said complex number sequences and forwarding said complex number sequences to said control site;

processing means for processing complex numbers received at said control site using different postulates of pager location to produce combined complex number sequences corresponding to enhanced reception from different locations; and

correlation means for correlating said combined sequences with a predetermined signal pattern to produce a detection indication and a location indication.

2. A paging network according to claim 1 which directs further information transmissions to a pager using a site and a direction based on said location indication.

3. A paging network capable of transmitting short messages to and receiving short replies from portable paging units comprising:

a control site having means for controlling transmitter and receiver sites and sending information thereto and receiving information therefrom;

at least one transmitter site for transmitting short messages addressed to individual paging units;

at least two receiving sites each including;

plural antennas connected to respective receive channel signal processing units for converting received signals to corresponding sequences of complex numbers;

a synchronization mechanism for receiving a synchronization indication from said control site to control said receive channel processing unit and converting activity in time relation to said transmitter site'"'"'s transmissions;

memory means for storing said complex number sequences and forwarding said complex number sequences to said control site;

correlation means for correlating complex number sequences received at said control site with a predetermined signal pattern using different postulates of time of arrival and direction of arrival at each of said at least two receiver sites to produce TOA and DOA-corresponding correlation values; and

combining means for combining said correlations using different postulates of pager location relative to said receiver sites to produce a detection indication and a location indication.

4. A paging network according to claim 3 which directs further information transmissions to a pager using a site and a direction based on said location indication.

5. A two-way paging network capable of transmitting short messages to and receiving short messages from portable paging units, comprising:

antennas connected to respective receive channel processing units which convert respective received signal samples to corresponding sequences of complex numbers;

memory means for storing said complex numbers and a complex coefficient matrix;

arithmetic unit means for combining said stored complex numbers with said stored complex coefficient matrix to produce combined sequences each representing signal reception from a particular direction;

correlation means for correlating each of said combined sequences with at least two predetermined signal patterns of which one is an expected acknowledgment from a paging unit and another is a random access code in order to produce an acknowledgment detection indication and a random access indication and associated direction indications; and

decoding means activated by said random access indication to further process selected ones of said combined sequences as indicated by said associated direction indications in order to decode a random access message from a portable paging unit.

6. A two-way paging network capable of addressing short messages to and receiving short messages from portable paging units, comprising:

antennas connected to respective receive channel processing units which convert respective received signal samples to corresponding sequences of complex numbers;

processing means for processing said complex number sequences to attempt to detect a first signal pattern corresponding to an expected acknowledgment from a paging unit to which a short message has been addressed and to attempt to detect a signal pattern indicating a random access transmission from the same or a different paging unit; and

decoding means activated by detection of a random access indication to further process said complex number sequences to decode a random access message from a portable paging unit.

7. A two-way paging network capable of transmitting short messages to and receiving short messages from portable paging units, comprising:

antennas connected to respective receive channel processing units for converting respective received signal samples to corresponding sequences of complex numbers;

memory means for storing said complex numbers and a complex coefficient matrix;

arithmetic unit means for combining said stored complex numbers with said stored complex coefficient matrix in order to produce combined sequences each representing signal reception from a particular direction;

correlation means for correlating each of said combined sequences with a predetermined signal pattern indicative of a random access attempt by at least one of said paging units in order to produce random access indications and associated direction indications; and

decoding means activated by said random access indications to further process selected ones of said combined sequences as indicated by said associated direction indications in order to decode a random access message from at least one portable paging unit.