Enhanced throughput in simulcast communication systems

• US 5,260,700 A
• Filed: 09/16/1992
• Issued: 11/09/1993
• Est. Priority Date: 06/12/1990
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Moore, Morris, Merchant, Zaffer
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Horabik, Michael
• Application Number:
  US07/945,572
• Time in Patent Office: 419 Days
• Field of Search: 340/825.44, 340/825.47, 340/825.48, 340/825.49, 340/313, 340/504, 371/32, 371/33, 455/33.1, 455/33.3, 455/38.1, 455/52.1, 455/54.1, 455/69, 455/70, 455/343, 370/84, 370/110.1, 379/59, 379/63
• 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: H04L 1/0006 by adapting the transmission format
• CPC Class Codes: H04L 1/1664 the supervisory signal being transmitted together with payload signals; piggybacking
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04W 88/185 Selective call encoders for paging networks, e.g. paging centre devices

Abstract

A selective call receiver system includes a plurality of base sites capable of simultaneous operation. Each base site includes a transmitter and a base receiver capable of measuring the signal strength of a received signal. A controller coupled to the plurality of base sites, forwards an address to the plurality of base sites. The transmitters thereafter, simultaneously transmit the address to at least one of a plurality of selective call receivers having acknowledge-back capability. At least one of the plurality of base receivers receive an acknowledge-back signal from the at least one of the selective call receivers responding to the transmitted address. The signal strength of the acknowledge-back signal is detected by the plurality of base receivers receiving the acknowledge-back signal. The controller has a determining circuit for determining a value representing the signal strength of the acknowledge-back signal, and an encoder, coupled to the determining circuit, encoding a single copy of the message in a first format or a second format. The encoder encodes the message to derive the single copy of the message in the first format when the value determined by the determining circuit is above a predetermined level and encodes the message with an error correcting code to derive the single copy of the message in the second format when the value determined by the determining circuit is below the predetermined level. The controller thereafter forwards the single copy of the encoded message to the base site.

Claims

1. A selective call receiver system comprising:

a plurality of base sites capable of simultaneous operation, each including a transmitter and a base receiver capable of measuring the signal strength of a received signal; and

controller means for forwarding an address to said plurality of base sites, said transmitters simultaneously transmitting the address to at least one of a plurality of selective call receivers having acknowledge-back capability, at least one of said plurality of base receivers receiving an acknowledge-back signal from the at least one of said selective call receivers responding to the transmitted address, the signal strength of said acknowledge-back signal being detected by said plurality of base receivers receiving the acknowledge-back signal, said controller means comprising;

determination means for determining a value representing the signal strength of the acknowledge-back signal and said determination means further determines the signal strength of the strongest acknowledge-back signal when two or more base receivers have received the acknowledge-back signal and the base site receiving the strongest acknowledge-back signal; and

encoder means for encoding a single copy of the message in a first format or a second format wherein said encoder means encodes the message in the first format when the signal strength is below a predetermined level and encodes the message in the second format when the signal strength is above the predetermined level, said controller thereafter forwarding the single copy of the encoded message to the determined base site.

2. The selective call receiver system according to claim 1 wherein the transmitter is capable of transmitting addresses at a first data rate.

3. The selective call receiver system according to claim 1 wherein the transmitter is capable of transmitting messages at a second data rate.

4. The selective call receiver system according to claim 1 wherein the signal transmitted in the first format comprises a non-error correction coded message.

5. The selective call receiver system according to claim 1 wherein the signal transmitted in the second format comprises an error correction coded message.

6. The selective call receiver system according to claim 4 wherein the signal is interleaved before transmission by the controller.

7. The selective call receiver system according to claim 5 wherein the signal is interleaved before transmission by the controller.

8. In a selective call receiver system, a method for transmitting messages, comprising the steps of:

(a) transmitting an address to at least one selective call receiver having acknowledge-back capability;

(b) receiving an acknowledge-back signal from the at least one of the selective call receiver in response to the transmitted address;

(c) determining a value for representing signal strength of the received acknowledge-back signal;

(d) encoding a single copy of the message into a first format when the value exceeds a predetermined threshold, and into a second format when the value is below the predetermined threshold; and

(e) transmitting the single copy of the message in the encoded format.

9. The method according to claim 8 wherein step (a) further comprises the step of transmitting the address at a first data rate from a plurality of base sites and thereafter wherein step (e) comprises the step of transmitting the message at a second data rate substantially higher than the first data rate from the base site receiving the acknowledge-back signal having the highest signal strength.

10. A selective call receiver comprising:

receiving means for receiving a predetermined address at a first data rate and receiving a single copy of a subsequent message encoded in a first or second format at a second data rate substantially higher than the first data rate, the message including a control information identifying the format of the message;

transmitter means for transmitting an acknowledge-back signal in response to the received predetermined address, and

processor means coupled to the receiver means for determining whether to process the received message in the first or second format in response to the received control information.

11. The selective call receiver according to claim 10 wherein the first format includes a non-error correction coded message and the second format includes an error correction coded message.

12. The selective call receiver according to claim 10 wherein an interleaved encoded received message is deinterleaved before processing by the processing means.

13. A method for receiving message with a selective call receiver having acknowledge-back capability, comprising the steps of:

a) receiving a predetermined address;

b) transmitting an acknowledge-back signal in response to the predetermined address;

c) receiving a single copy of a message encoded in a first or second format including control information indicative of the message format; and

d) processing the control information to determine whether to process the message in accordance with the first or second format, wherein the first format includes an uncoded message and the second format includes an error correction coded message.

14. The method according to claim 13 wherein step (a) comprises the step of receiving the address from one of a plurality of base sites and step (c) comprises the step of receiving the message from one predetermined base site receiving the acknowledgement with the highest signal strength.

15. A selective call receiver system comprising:

a plurality of base sites capable of simultaneous operation, each including a transmitter and a base receiver capable of measuring the signal strength of a received signal; and

controller means, coupled to said plurality of base sites, for forwarding an address to said plurality of base sites, said transmitters simultaneously transmitting the address to at least one of a plurality of selective call receivers having acknowledge-back capability, at least one of said plurality of base receivers receiving an acknowledge-back signal from the at least one of said selective call receivers responding to the transmitted address, the signal strength of said acknowledge-back signal being detected by said plurality of base receivers receiving the acknowledge-back signal, said controller comprising;

determination means for determining a value representing the signal strength of the acknowledge-back signal; and

encoder means, coupled to said determination means, for encoding a single copy of the message in a first format or a second format wherein said encoder means encodes the message to derive the single copy of the message in the first format when the value determined by the determination means is above a predetermined level and encodes the message with an error correcting code to derive the single copy of the message in the second format when the value determined by the determination means is below the predetermined level, said controller thereafter forwarding the single copy of the encoded message to the base site.

16. The selective call receiver system according to claim 15 wherein said determination means further determines the signal strength of the strongest acknowledge-back signal when two or more base receivers have received the acknowledge-back signal and determines the base site receiving the strongest acknowledge-back signal.

17. In a selective call receiver system, a method for transmitting messages, comprising the steps of:

(a) transmitting an address to at least one selective call receiver having acknowledge-back capability;

(b) receiving an acknowledge-back signal from the at least one of the selective call receiver in response to the transmitted address;

(c) determining a value for representing signal strength of the received acknowledge-back signal;

(d) encoding a single copy of the message into a first format or a second format wherein said step of encoding encodes the message to derive the single copy of the message in the first format having no error correction code when the value determined by step (c) is above a predetermined level and encodes the message and information for error correcting the message to derive the single copy of the message in the second format when the value determined by step (c) is below the predetermined level; and

(e) transmitting the single copy of the message in the encoded format.

18. A selective call receiver comprising:

receiving means for receiving a predetermined address at a first data rate and receiving a single copy of a subsequent message encoded in a first or second format at a second data rate substantially higher than the first data rate, the message including a control information identifying the format of the message;

transmitter means, coupled to said receiving means, for transmitting an acknowledge-back signal in response to the received predetermined address, and

processor means coupled to the receiver means for determining whether to process the received message in the first or second format in response to the received control information wherein the processor means, in response to the control information, processes the message in the first format as having no error correction code to derive the single copy of message, and processes the message in the second format as having error correction code to derive the single copy of the message.

19. A method for receiving message with a selective call receiver having acknowledge-back capability, comprising the steps of:

a) receiving a predetermined address;

b) transmitting an acknowledge-back signal in response to the predetermined address;

c) receiving a single copy of a message encoded in a first or second format including control information indicative of the message format; and

d) processing the control information to determine whether to process the message in accordance with the first or second format, wherein the step of processing, in response to the control information, processes the message in the first format as having no error correction code to derive the single copy of message, and processes the message in the second format as having error correction code to derive the single copy of the message.

20. A selective call receiver system comprising:

a plurality of base sites capable of simultaneous operation, each including a transmitter and a base receiver capable of measuring the signal strength of a received signal; and

controller means, coupled to said plurality of base sites, for forwarding an address to said plurality of base sites, said transmitters simultaneously transmitting the address to at least one of a plurality of selective call receivers having acknowledge-back capability, at least one of said plurality of base receivers receiving an acknowledge-back signal from the at least one of said selective call receivers responding to the transmitted address, the signal strength of said acknowledge-back signal being detected by said plurality of base receivers receiving the acknowledge-back signal, said controller comprising;

determination means for determining a value representing the signal strength of the acknowledge-back signal; and

encoder means, coupled to said determination means, for encoding a single copy of the message in a non-error correcting format or an error correcting format wherein said encoder means encodes the message to derive the single copy of the message in the non-error correcting format when the value determined by the determination means is above a predetermined level and encodes the message and information for error correcting the message to derive the single copy of the message in the error correcting format when the value determined by the determination means is below the predetermined level, said controller thereafter forwarding the single copy of the encoded message to the base site.

21. In a selective call receiver system, a method for transmitting messages, comprising the steps of:

(a) transmitting an address to at least one selective call receiver having acknowledge-back capability;

(b) receiving an acknowledge-back signal from the at least one of the selective call receiver in response to the transmitted address;

(c) determining a value for representing signal strength of the received acknowledge-back signal;

(d) encoding a single copy of the message into a non-error correcting format or an error correcting format wherein said step of encoding encodes the message to derive the single copy of the message in the non-error correcting format having no error correction capability when the value determined by step (c) is above a predetermined level and encodes the message and information for error correcting the message to derive the single copy of the message in the error correcting format when the value determined by step (c) is below the predetermined level; and

(e) transmitting the single copy of the message in the encoded format.

22. A selective call receiver comprising:

receiving means for receiving a predetermined address at a first data rate and receiving a single copy of a subsequent message encoded in a non-error correcting format or error correcting format at a second data rate substantially higher than the first data rate, the message including a control information identifying the format of the message;

transmitter means, coupled to said receiving means, for transmitting an acknowledge-back signal in response to the received predetermined address, and

processor means coupled to the receiver means for determining whether to process the received message in the non-error correcting format or the error correcting format in response to the received control information wherein the processor means, in response to the control information, processes the message in the non-error correcting format as having no error correction capability to derive the single copy of message, and processes the message in the error correcting format as having error correction code to derive the single copy of the message.

23. A method for receiving message with a selective call receiver having acknowledge-back capability, comprising the steps of:

a) receiving a predetermined address;

b) transmitting an acknowledge-back signal in response to the predetermined address;

c) receiving a single copy of a message encoded in a non-error correcting format or an error correcting format including control information indicative of the message format; and

d) processing the control information to determine whether to process the message in accordance with the non-error correcting format or error correcting format, wherein the step of processing, in response to the control information, processes the message in the non-error correcting format as having no error correction capability to derive the single copy of message, and processes the message in the error correcting format as having error correction code to derive the single copy of the message.