Datagram communication service over a cellular telephone network

• US 5,481,539 A
• Filed: 06/29/1994
• Issued: 01/02/1996
• Est. Priority Date: 06/29/1994
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hassan, Amer A., Hershey, John E.
• Primary Examiner(s): Hsu, Alpus
• Application Number:
  US08/267,328
• Time in Patent Office: 552 Days
• Field of Search: 370/13, 370/13.1, 370/60, 370/85.2, 370/85.3, 370/85.6, 370/85.7, 370/85.13, 370/94.1, 370/94.3, 370/95.1, 370/95.3, 379/58, 379/59, 379/60, 455/7, 455/9, 455/11.1, 455/33.1, 455/33.2, 455/34.1, 455/34.2, 455/53.1, 455/54.1, 455/54.2, 455/56.1, 455/88, 455/89, 340/825.5, 340/825.51, 371/32, 371/33
• US Class Current: 370/312
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A highly fault tolerant method of radio communication piggybacked upon time division multiple access (TDMA) digital cellular radio telephone systems transmits message packet through a distributed network of transmitter/receivers, (tranceivers) mobile units, each having a unique identification (ID) number. An initiating mobile unit creates a message packet having the ID of a mobile unit intended to receive the message packet. It then broadcasts the message packet in a non-interfering fashion to local mobile units within its transmission range, at a time period which does not overlap a time slot in which it communicates with a cellular base unit. Each mobile unit which receives the message packet checks to see if there are errors and sends an acknowledgement if no errors. The mobile units determine valid message packets by determining if the message has not expired, if it has not been seen before and there were no errors in the received message packet. The mobile unit also determines if the transceiver ID in the message packet matches its own transceiver ID, and if it does, the message has been successfully transmitted to its intended mobile unit. If the message packet is valid and the mobile unit IDs do not match, the mobile unit broadcasts the message to other local mobile units until a predetermined number of acknowledgements are received, or until the message expires. The mobile units which receive the message packet repeat the process. A message is transmitted from a sending mobile unit to a receiving mobile unit without any interaction with a cellular base unit.

Claims

1. A method of transmitting message information from an initiating unit to a destination unit over a time division multiple access (TDMA) mobile radio network having a plurality of mobile units, each with a unique internal identification (ID) number, comprising the steps of:

a) determining a destination unit identification number (ID) for said destination unit desired to receive information packet;

b) creating a message packet having a message ID, the destination unit ID, and said message information;

c) determining a time slot assigned to said initiating unit;

d) broadcasting the message packet to recipient mobile units in a non-interfering fashion at a time period other than that assigned to said initiating unit;

e) for each recipient mobile unit receiving the broadcast;

3. The method of transmitting message information of claim 1 further comprising, after the step of re-broadcasting the message packet, the steps of:

a) listening for an acknowledgment (ACK) signal from a recipient mobile unit which has received the message packet without error;

b) comparing a count of ACK signals received to a ROBUSTNESS value in the message packet;

c) deleting the message except for the message ID if the count of ACK signals meets or exceeds the ROBUSTNESS value, and

d) determining if the message has expired and erasing the message if it has expired, and

e) re-broadcasting the message packet to other recipient mobile units in a non-interfering fashion at a time period other than that assigned to this recipient mobile unit if the message is a valid message packet; and

f) repeating steps a-e if the message packet has not expired and the count of ACK signals does not exceed the ROBUSTNESS value.

4. The method of transmitting information of claim 1 further comprising, after the step of re-broadcasting the message packet, the steps of:

a) detecting if a collision has occurred; and

b) re-broadcasting valid message packet after a randomized delay period at a time period other than the slot assigned to this recipient mobile unit to reduce the possibility of another collision.

2. checking for errors in the received message packet, and transmitting an ackowledgment signal if received with no errors,identifying if the message is a valid message packet, a valid message packet being one which was received without errors, has not expired and is has an message ID which does not match stored message IDs,comparing the destination unit ID to the intemal ID of the recipient mobile unit for the message if it is a valid message packet,storing and utilizing valid message packets which the destination unit ID matches the intemal ID of the recipient mobile unit,determining a time slot assigned to this recipient mobile unit if the message is a valid message packet, andre-broadcasting the message packet to other recipient mobile units in a non-interfering fashion at a time period other than that assigned to this recipient mobile unit if the message is a valid message packet.