Method for reliable exchange of modem handshaking information over a cellular radio carrier

• US 6,366,609 B1
• Filed: 12/10/1998
• Issued: 04/02/2002
• Est. Priority Date: 07/29/1996
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Rossi, Markku J.
• Primary Examiner(s): VO, DON NGUYEN
• Application Number:
  US09/481,801
• Time in Patent Office: 1,209 Days
• Field of Search: 375/220, 375/222, 375/223, 375/356, 375/358, 375/377, 370/328, 370/338, 370/465, 370/467, 455/422, 455/557, 455/575
• US Class Current: 375/222
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision
• CPC Class Codes: H04W 4/12 Messaging; Mailboxes; Announcements

Abstract

A technique for reliable passage of handshaking information between a cellular modem and a land modem. Instead of bare transmission over a voice channel connection highly susceptible to signal fading and dropout, the initial modem handshaking exchange is instead FSK-encoded and broadcast using a network data signalling methodology already used to reliably pass signalling information between the base and registered mobiles. Automatic retransmission request signalling and transmission redundancy may be implemented to insure successful receipt at the receiving end of the radio link. Once received and verified, handshaking information is decoded and delivered to the destination modem in the appropriate format along cleaner fixed pathways. Reliable handshaking operations are contemplated whether the destination modem is a cellular modem registered in auto-answer mode (land-originated data call), or a land modem (mobile-originated data call). Backwards compatibility with non-compatible cellular fixed-ends or mobiles is maintained through extensive use of active acknowledgment messaging and software timed transactions.

Claims

1. A mobile communications apparatus for transmitting modem handshaking data to a wireless network through a wireless mobile transceiver, the apparatus comprising:

a mobile computer;

a wireless modem adapted to be coupled to said mobile computer through a first electrical interface, said wireless modem further adapted to be coupled through a second electrical interface to the wireless mobile transceiver, wherein said wireless modem is configured to download handshaking signals to the wireless mobile transceiver indicating a request for a data connection to a destination land modem of the wireless network; and

a program stored in both the wireless mobile transceiver and the wireless modem, which, when executed, performs the following steps;

selectively interposing a first modem between a mobile switching center and the destination land modem to establish a data connection; and

selectively interposing a second modem between the mobile switching center and the destination land modem for synchronization.

2. The mobile communications apparatus of claim 1, wherein said second electrical interface comprises a digital bus connection for passing control-related information in a digital format and an analog voice line for carrying modulated data.

3. The mobile communications apparatus of claim 2, wherein except for said digital bus connection, said wireless modem otherwise conforms to any UN/ITU recognized protocol.

4. The mobile communications apparatus of claim 1, wherein said wireless modem is detachable from said computer system.

5. A mobile communications apparatus for transmitting modem handshaking data to a wireless network through a wireless mobile transceiver, the apparatus comprising:

a mobile computer;

a wireless modem;

a first electrical interface coupling said mobile computer to said wireless modem;

a second electrical interface coupling said wireless modem to the wireless mobile transceiver, said wireless modem downloading the handshaking signals to the wireless mobile transceiver to indicate a request for a data connection to the wireless network; and

a program stored in the both wireless mobile transceiver and the wireless modem, which, when executed, performs the following steps;

selectively interposing a first modem between a mobile switching center and the destination land modem to establish a data connection, and

selectively interposing a second modem between the mobile switching center and the destination land modem for synchronization.