Acknowledge back pager with adaptive variable transmitter output power

• US 4,825,193 A
• Filed: 01/07/1988
• Issued: 04/25/1989
• Est. Priority Date: 01/07/1988
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Siwiak, Kazimierz, Jasinski, Leon, Steel, Francis R.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US07/141,370
• Time in Patent Office: 474 Days
• Field of Search: 340/311.1, 340/502, 340/539, 340/693, 340/825.44-825.48, 340/825.5, 340/825.51, 455/53-56, 455/127, 455/229
• US Class Current: 340/7.22
• CPC Class Codes: H04W 84/025 with acknowledge back capability

Abstract

An acknowledge back (ack-back) pager is provided for receiving paging signals from a central paging station. The central paging station transmits a group of message signals to a group of ack-back pagers which are addressed as a group. The users of the group of addressed ack-back pagers indicate a response to their respective pagers thus providing ack-back data. The pagers in the group of addressed ack-back pagers then simultaneously transmit back to the central station their ack-back data on different frequency sub-bands, a different frequency sub-band being dynamically allocated to each of the pagers in the group. Each ack-back pager determines whether the paging signals received thereby exhibits a signal level less than a predetermined threshold level. If the paging signals received by a particular ack-back pager exhibit a signal level less than such predetermined threshold level, then the pager transmits back to the central station at a first output power level. Otherwise, the pager transmits at a second ouput power level substantially less than the first output power level. In this manner, the problem of the ack-back signal from a particular pager being so strong at the central station as to mask other simultaneous ack-back signals is substantially ameliorated.

Claims

1. An acknowledge back pager having a unique address associated therewith, said pager comprising;

receiving means for receiving paging signals from a central station thus producing received paging signals;

threshold detecting means, coupled to said receiving means, for determining if the signal level of said received paging signals exceeds a predetermined threshold level, and

sub-band transmitting means for transmitting an acknowledge back signal on a selected one of a plurality of M predetermined frequency sub-bands, said transmitting means transmitting being coupled to said threshold detecting means and transmitting acknowledge back signals at a first output power level when said threshold detecting means determines that the signal level of said received paging signals is less than said predetermined threshold level, said transmitting means otherwise transmitting acknowledge back signals at a power level substantially less than said first output power level.

2. The acknowledge back pager of claim 1 wherein said receiving means receives paging signals from a central station, said paging signals including a batch of M pager addresses transmitted in a sequential order during a first time period, wherein M is the number of pager addresses in said batch, said receiving means thus producing received paging signals, said pager including

decoding means, coupled to said receiving means, for detecting the presence of said pager'"'"'s address within said batch of M addresses.

3. The acknowledge back pager of claim 2 including alert means for providing an alert to indicate to a user of an addressed one of said M pagers that said pager has been addressed.

4. The acknowledge back pager of claim 1 including a response indicating means wherein a user of said pager indicates a response to said pager for transmission in said acknowledge back signal.

5. The acknowledge back pager of claim 1 including means for receiving and displaying message signals transmitted by said central station in a second time period subsequent said first time period.

6. An acknowledge back pager having a unique address associated therewith, said pager comprising;

receiving means for receiving paging signals from a central station, said paging signals including a batch of M pager addresses transmitted in a sequential order during a first time frame, wherein M is the number of pager addresses in said batch, said receiving means thus producing received paging signals;

decoding means, coupled to said receiving means, for detecting the presence of said pager'"'"'s address within said batch of M addresses;

address order determining means, coupled to said decoding means, for determining the order of said pager'"'"'s address within said batch of M addresses;

threshold detecting means, coupled to said receiving means, for determining if the signal level of said received paging signals exceeds a predetermined threshold level;

sub-band transmitting means for transmitting an acknowledge back signal on a selected one of a plurality of M predetermined frequency sub-bands, said selected one of said sub-bands exhibiting a predetermined relationship to the order of the address of said pager within said batch of M addresses, said transmitting means transmitting being coupled to said threshold detecting means and transmitting acknowledge back signals at a first output power level when said threshold detecting means determines that the signal level of said received paging signals is less than said predetermined threshold level, said transmitting means otherwise transmitting acknowledge back signals at a power level substantially less than said first output power level.

7. The acknowledge back pager of claim 6 including alert means for providing an alert to indicate to a user of an addressed one of said M pagers that said pager has been addressed.

8. The acknowledge back pager of claim 6 including a response indicating means wherein a user of said pager indicates a response to said pager for transmission in said acknowledge back signal.

9. The acknowledge back pager of claim 6 including means for receiving and displaying message signals transmitted by said central station in a second time period subsequent to said first time period.

10. An acknowledge back pager having a unique address associated therewith, said pager comprising;

receiving means for receiving paging signals from a central station thus producing received paging signals;

threshold detecting means, coupled to said receiving means, for determining if the signal level of said received paging signals is less than a predetermined threshold level;

memory means for storing indicia of the signal strength of said received paging signals as determined by said threshold detecting means;

transmitting means for transmitting acknowledge back signals on a selected one of a plurality of different frequency sub-bands simultaneously with acknowledge back signals transmitted by other acknowledge back pagers, said transmitting means transmitting at a first output power level when a first signal is supplied thereto and transmitting at a second power output level substantially less than said first output power level when a second signal is provided thereto, and

microcomputer means, coupled to said receiving means, to said transmitting means and to said memory means, for processing paging signals received by said paging means, said microcomputer means providing said first signal to said transmitting means when said received paging signals are less than said predetermined threshold level and otherwise providing said second signal to said transmitting means.

11. The acknowledge back pager of claim 10 wherein said receiving means receives paging signals from a central station, said paging signals including a batch of M pager addresses transmitted in a sequential order during a first time period, wherein M is the number of pager addresses in said batch, said receiving means thus producing received paging signals, said microcomputer means including

decoding means for detecting the presence of said pager'"'"'s address within said batch of M addresses.

12. The acknowledge back pager of claim 11 including alert means for providing an alert to indicate to a user of an addressed one of said M pagers that said pager has been addressed.

13. The acknowledge back pager of claim 10 including a response indicating means wherein a user of said pager indicates a response to said pager for transmission in said acknowledge back signal.

14. The acknowledge back pager of claim 10 including means for receiving and displaying message signals transmitted by said central station.

15. In a radio paging system including a central paging station for transmitting address and message signals to a plurality of remotely located radio pagers, each pager having an address corresponding thereto, a method of operation of an acknowledge back pager comprising the steps of:

receiving paging signals from said central station thus producing received paging signals exhibiting a signal level;

determining if the signal level of said received paging signals exceeds a predetermined threshold level, and

transmitting an acknowledge back signal on a selected one of a plurality of M predetermined frequency sub-bands at a first output power level when the signal level of said received paging signals is less than said predetermined threshold level and otherwise transmitting acknowledge back signals at a power level substantially less than said first output power level.