Reliable message delivery system

• US 5,396,537 A
• Filed: 10/19/1992
• Issued: 03/07/1995
• Est. Priority Date: 09/30/1992
• Status: Expired due to Term

• Current Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Schwendeman, Robert J.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): OEHLING, GEORGE J
• Application Number:
  US07/963,370
• Time in Patent Office: 869 Days
• Field of Search: 379/56, 379/57, 379/58, 379/93, 379/97, 379/98, 379/99, 340/825.44, 340/311.1, 340/825.07, 340/825.15, 340/825.17, 370/94.1, 358/437, 358/439, 358/441
• US Class Current: 340/7.23
• CPC Class Codes: H04M 11/022 Paging systems personal calling arrangements or devices G08B3/1008; selective calling networks H04W84/022
• CPC Class Codes: H04W 88/185 Selective call encoders for paging networks, e.g. paging centre devices

Abstract

A method and apparatus for reliably delivering messages (200) from a central terminal (102) to a communication receiver (130) in a communication system (100), such as an electronic mail system. The central terminal (102) transmits messages (1300) to the communication receiver (130) and the communication receiver (130) receives transmitted messages (1300) over a first communication medium (122). The communication receiver (130) reconciles messages that it failed to receive over the first communication medium (122) with the central terminal (102) over a second communication medium (152). The reconciliation process between the communication receiver (130) and the central terminal (102) utilizes cyclic redundancy codes (CRCs) transmitted with the messages (1300) to identify the messages (1300) being reconciled.

Claims

1. A method in a communication system for reliably delivering messages to at least one portable selective call receive from a communication controller the method comprising within the communication controller, the steps of:

(a) storing messages comprising address cyclical redundancy codes (CRCs), and message data;

(b) transmitting the messages over a first communication medium for reception by at least one portable selective call receiver, wherein the CRCs transmitted within the messages are unique according to corresponding message data and are used to identify the corresponding message data;

(c) receiving a message reconciliation request from one portable selective call receiver of the at least one portable selective call receiver over a second communication medium, different than the first communication medium, the message reconciliation request identifying a predetermined address for the one portable selective call receiver;

(d) reconciling stored messages with the one portable selective call receiver over the second communication medium using the CRCs to identify the transmitted messages to determine a reception status of the transmitted messages for the one portable selective call receiver; and

(e) transmitting to the one portable selective call receiver, over the second communication medium, at least the message data of the transmitted messages having a reception status indicating that the one portable selective call receiver failed to receive the transmitted messages for reliably delivering messages to the at least one portable selective call receiver in the communication system.

2. The method of claim 1 wherein the first communication medium is a radio frequency paging channel.

3. The method of claim 1 wherein the second communication medium is a dial-up telephone line interface using modem communication,

4. The method of claim 1 wherein the second communication medium is a radio frequency communication channel,

5. The method of claim 1 wherein step (d) comprises the steps of:

(f) handshaking the CRCs of the stored messages that include the address information matching the predetermined address to the one portable selective call receiver; and

(g) receiving acknowledgment from the one portable selective call receiver indicating the reception status of the messages identified by the handshaking of the CRCs.

6. The method of claim 5, wherein the one portable selective call receiver performs the, steps of:

(h) receiving the messages transmitted in step (b);

(i) searching the received messages that included address information matching the predetermined address identified in the message reconciliation request for matching the handshaking CRCs to the CRCs of the searched messages;

(j) after determining that there is no match between one of the CRCs handshaking in step (f) and the CRCs of the searched messages, transmitting the acknowledgment indicating a reception status that the one portable selective call receiver failed to receive a message corresponding to the one of the CRCs handshaking in step (f);

add

(k) receiving at least the message data of the message indicated as having been failed to received in step (j) over the second communication medium for reliably delivering messages to the at least one portable selective call receiver in the communication system.

7. The method of claim 5, wherein the one portable selective call receiver performs the steps of:

(l) receiving the messages transmitted in step (b);

(m) determining from a corresponding CRC that there is an error in one of the received messages;

(n) identifying the predetermined address in the message reconciliation request matching the address information of the one of the received messages;

(o) matching one of the CRCs handshaking in step (f) with the corresponding CRC of the one of the received messages;

(p) transmitting an acknowledgment in step (g) indicating a reception status that the one portable selective call receiver failed to receive the one of the received messages; and

(q) receiving at least the message data of the one of the received messages indicated in step (p) over the second communication medium for reliably delivering messages to the at least one portable selective call receiver in the communication system.

8. The method of claim 7, wherein step (m) comprises the step of:

(r) determining error in one of the received messages by comparing the CRC of the one of the received messages to a computed value based on the content of the one of the received messages.

9. A method in a communication system for reliably delivering messages from a communication controller to at least one portable selective call receiver, the method comprising the steps of:

(a) storing messages at the communication controller, the messages comprising address information, cyclical redundancy codes (CRCs), and message data;

(b) transmitting the messages from the communication controller over a first communication medium for reception by at least one portable selective call receiver, wherein the CRCs transmitted within the messages are unique according to the corresponding message data and are used to identify the message data;

(c) receiving a message reconciliation request at the communication controller from the at least one portable selective call receiver over a second communication medium, different than the first communication medium, the message reconciliation request identifying a predetermined address for the portable selective call receiver;

(d) searching the messages stored at the communication controller for locating the messages that were transmitted which include address information matching the predetermined address identified in step (c);

(e) transmitting at least one of the CRCs of at least one of the messages found in step (d) from the communication controller to the at least one portable selective call receiver over the second communication medium;

(f) verifying at the at least one portable selective call receiver, in response to receiving the at least one of the CRCs at the portable selective call receiver, whether the portable selective call receiver failed to receive the at least one of the messages identified by the at least one of the CRCs, respectively;

(g) transmitting a reconciliation acknowledgment from the portable selective call receiver to the communication controller over the second communication medium to confirm a reception status of the at least one of the messages identified by the at least one of the CRCs verified in step (f) the reception status indicating that the portable selective call receiver failed to receive the at least one of the messages or that it correctly and completely received the at least one of the messages; and

(h) transmitting at least the message data of the at least one of the messages identified by the at least one of the CRCs being acknowledged in the reconciliation acknowledgment from the communication controller to the portable selective call receiver over the second communication medium, the reconciliation acknowledgment confirming that the portable selective call receiver failed to receive the at least one of the messages identified by the at least one of the CRCs.

10. A communication system for reliably delivering messages to at least one communication receiver, the communication system comprising:

first memory means for storing messages destined for transmission to at least one communication receiver, the messages comprising address information, message data, and cyclical redundancy codes (CRCs) which are unique according to corresponding message data and are used to identify the corresponding message data;

first message transmitting means coupled to the memory means for transmitting the messages over a first communication medium for reception by the at least one communication receiver;

second message transmitting means coupled to the memory means for transmitting at least the message data of the messages over a second communication medium for reception by the at least one communication receiver, the second communication medium being different than the first communication medium;

retrieving means for retrieving messages stored in the first memory means; and

message reconciliation request processing means coupled to the retrieving means and to the second message transmitting means for receiving a message reconciliation request from the at least one communication receiver over the second communication medium, and in response to the message reconciliation request;

determining that at least one message was not received by the at least one communication receiver over the first communication medium,

retrieving at least the message data of the at least one message from the first memory means, least the message data of the at least one message being identified by the CRC of the at least one message, and

transmitting the message data of the at least one message over the second communication medium for reception by the at least one communication receiver, for reliably delivering messages from the communication system to the at least one communication receiver over at least one of the first communication medium and the second communication medium; and

the at least one communication receiver for communicating with the communication system over the first communication medium and the second communication medium.

11. The communication system of claim 10 wherein the second communication medium is a dial-up telephone line interface using modem communication.

12. The communication system of claim 10 wherein the second communication medium is a radio frequency communication channel.