Selective call receiver with battery saving features and method therefor

• US 5,381,133 A
• Filed: 01/25/1993
• Issued: 01/10/1995
• Est. Priority Date: 01/25/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Hayes, David J., Zuleta, Renee, Erhart, Richard A.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): MERZ, EDWARD W
• Application Number:
  US08/008,124
• Time in Patent Office: 715 Days
• Field of Search: 340/825.44, 455/38.3, 455/343, 379/57
• US Class Current: 340/7.35
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 88/022 Selective call receivers
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A selective call receiver (200) includes a receiver (204) receiving paging signals including a preamble, a synchronization codeword, and at least address information. A controller (206) controlling a supply of power to the receiver for receiving the paging signals. A synchronization obtaining circuitry (404, 406, 224), coupled to the receiver (204), obtains synchronization to the paging signal. The synchronization obtaining circuitry (404, 406, 224) includes a baud rate detector and synchronization codeword detector, coupled to the baud rate detector, detects the synchronization codeword. An address decoder, responsive to the synchronization codeword being detected, decodes the address information. A synchronization maintaining circuitry (404, 408, 224) maintains synchronization to the paging signals during address decoding. The synchronization maintaining circuitry (404, 408, 224) includes circuitry for enabling the power switch (210) which enables the receiver (204) for receiving the paging signals. The baud rate detector (224), responsive to the power being supplied to the receiver (204), detects baud rate during at least first (150) and second (152) portions of the address. A preamble detector (404), responsive to the second portion of the address being received, detects preamble during at least a portion of a second address (152).

Claims

1. A selective call receiver, comprising:

a receiver for receiving paging signals including a preamble, a synchronization codeword, and at least an address;

a power switch for controlling a supply of power to said receiver for receiving the paging signals;

a baud rate detector, coupled to the receiver, for detecting a baud rate of the paging signals;

a decoder controller, coupled to said receiver, for obtaining synchronization to the paging signals, the decoder/controller comprising;

a preamble detector, responsive to the baud rate detector detecting a valid baud rate, for detecting preamble in the paging signals; and

a synchronization codeword detector, in response to the preamble being detected, for detecting the synchronization codeword; and

an address decoder, responsive to the synchronization codeword being detected, for decoding the address in an assigned frame of the paging signals;

the decoder/controller maintaining synchronization to the paging signals during address decoding by selectively enabling the power switch for controlling the supply of power to the receiver for receiving the paging signals;

said baud rate detector, responsive to power being supplied to said receiver, detects baud rate during a time period when the address decoder is decoding at least a first portion of the address, the address having at least the first portion and a second portion; and

the power switch supplies power to said receiver and the address decoder decodes the second portion of the address while the baud rate detector detects baud rate during said second portion of the address wherein the decoder/controller, in response to an invalid baud rate being detected, initiates the preamble detector for detecting preamble during the second portion of the address.

2. The selective call receiver according to claim 1 further comprising a disabling means for disabling power to said receiver when the invalid baud rate is detected.

3. The selective call receiver according to claim 1 further comprising an initiating means, responsive to said preamble detector decoding preamble in the second portion of address, for initiating an asynchronous receiving mode of said receiver.

4. The selective call receiver according to claim 3 wherein the initiating means initiates a synchronous receiving mode of said receiver in response to said decoder/controller being able to maintain synchronization to the paging signals during address decoding in the assigned frame.

5. A method for reducing power consumption in a selective call receiver which consumes power, the method comprising the steps of:

(a) receiving paging signals including a preamble, a synchronization codeword, and at least an address;

(b) controlling a supply of power for receiving the paging signals;

(b1) detecting a baud rate of the paging signals;

(c) obtaining synchronization to the paging signals wherein the steps of obtaining synchronization comprising the steps of;

(d) detecting preamble of the paging signals in response to step (b1) detecting a valid baud rate; and

(e) detecting the synchronization codeword responsive to step (d);

(f) decoding the address in response to step (e);

(g) maintaining synchronization to the paging signals during step (f), said step of maintaining synchronization, comprising steps of;

(h) selectively enabling the step (b) of controlling the power supply for receiving the paging signals;

(i) initiating said step (b1) of detecting baud rate during at least first and second portions of the address; and

(j) continuing the step (f) of decoding for decoding the second portion of the address while said step (b1) of detecting detects the baud rate during the second portion of the address and responsive to an invalid baud rate being detected, said step (d) of detecting detects preamble during the second portion of the address.

6. The method according to claim 5 wherein said step (c) of obtaining synchronization obtains synchronization in response to said step (b1) of detecting two invalid baud rates.

7. The method according to claim 5 wherein the step of initiating initiates the step of receiving for receiving paging signals in synchronous and asynchronous modes in response to the step (b1) of detecting valid baud rate and invalid baud rate respectively in the second portion of the address.

8. A selective call receiver, comprising:

a receiver for receiving paging signals including a preamble, a synchronization codeword, and at least an address;

a power switch for controlling a supply of power to said receiver for receiving the paging signals;

means coupled to the power switch for disabling power to said receiver;

a baud rate detector, coupled to the receiver, for detecting a baud rate of the paging signals;

a decoder controller, coupled to said receiver, for obtaining synchronization to the paging signals, the decoder/controller comprising;

a preamble detector detecting preamble in the paging signals in response to the baud rate detector detecting valid baud rate; and

a synchronization codeword detector, in response to the preamble being detected, for detecting the synchronization codeword; and

an address decoder, responsive to the synchronization codeword being detected, for decoding the address in an assigned frame of the paging signals;

the decoder/controller maintaining synchronization to the paging signals during address decoding by selectively enabling the power switch for controlling the supply of power to the receiver for receiving the paging signals;

said baud rate detector, responsive to power being supplied to said receiver, for detecting baud rate during a time period when the address decoder is decoding at least a first portion of the address, the address having at least the first portion and a second portion;

the power switch supplies power to said receiver and the address decoder decodes the second portion of the address while the baud rate detector detects baud rate during said second portion of the address wherein the decoder/controller, in response to an invalid baud rate being detected, initiates the preamble detector for detecting preamble during the second portion of the address; and

means, coupled to the receiver, for initiating an asynchronous mode of receiving of said receiver in response to the baud rate detector detecting two invalid baud rates.