EP0637150A1
Expired / Lapsed
EP
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A 1200 bit per second fallback method for use in mobile radio
Assignee: Paradyne Corp
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Filing: 1994-07-13
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Granted: —
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Expires: 2014-07-13
Abstract
Abstract In a mobile data communications system, a near-end modem (100) initiates a data connection to a far-end modem (300) at the highest permissible data rate, e.g., at 9600 bits per second (bps). If the communications channel subsequently degrades, either the near-end modem, or the far-end modem, initiates an autorate, or fallback sequence, e.g., to 4800 bps. However, if channel performance is still poor at 4800 bps, then one, or both, of the modems initiate a fallback to 1200 bps ― skipping over the data rate of 2400 bps, which is not included within the fallback sequence.
Inventors
- 👤 Joan E. Landry
- 👤 Mahendra Patel
- 👤 Robert Earl Scott
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:00
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/06; H04L; H04L1/00; H04L1/20; H04W; H04W28/00; H04W28/16; H04W28/18; H04W28/22; H04L1/12; H04L1/16; H04L1/18; H04L1/1803; H04L1/1867; H04L1/188
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
68 words
An autorating method for use in a modem, the method comprising the steps of: receiving a data signal from a far-end modem at a data rate of at least 4800 bits per second; detecting an error condition in the data signal; and responding to the detection of the error to change the data rate from the at least 4800 bits per second directly to 1200 bits per second.
Claim 2
Dependent Claim
31 words
The method of claim 1 wherein the received data signal represents a plurality of received packets and the error condition represents an error in at least one of the received packets.
Claim 3
Dependent Claim
48 words
The method of claim 1 wherein the received data signal represents a plurality of received packets and the error condition is the detection of the lack of an acknowledgment signal in these received packets for at least one prior transmitted packet from the modem to the far-end modem.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein the error condition represents a signal-to-noise ratio value for the received data signal that is higher than a predetermined signal-to-noise ratio reference value.
Claim 5
Dependent Claim
28 words
The method of claim 1 further including the step of demodulating a cellular carrier signal to provide the data signal before the step of receiving a data signal.
Claim 6
Dependent Claim
90 words
An autorating method for use in a modem, the method comprising the steps of: transmitting a data signal to a far-end modem at a data rate of at least 4800 bits per second, the data signal representing a plurality of data packets; detecting a lack of an acknowledgment signal for at least one of the plurality of data packets; and responding to the detection of the lack of an acknowledgment signal to change the data rate from the at least 4800 bits per second directly to 1200 bits per second.
Claim 7
Dependent Claim
66 words
The method of claim 6 wherein the step of detecting a lack of an acknowledgment signal includes the step of: setting a timer for a predetermined amount of time for the at least one of the plurality of data packets; and reaching the end of said predetermined amount of time without receiving the acknowledgment signal for the at least one of the plurality of data packets.
Claim 8
Dependent Claim
31 words
The method of claim 7 wherein the step of transmitting the data signal includes the step of modulating a cellular carrier with the data signal for transmission to the far-end modem.
Claim 9
Dependent Claim
73 words
Apparatus for providing an autorating feature in a modem, comprising: means for receiving (134) a data signal from a far-end modem at a data rate of at least 4800 bits per second; means for detecting an error condition (130) in the data signal; and means for responding to the detection of the error to change the data rate from the at least 4800 bits per second directly to 1200 bits per second. (110,120)
Claim 10
Dependent Claim
124 words
Apparatus for providing an autorating feature in a modem, comprising: means for transmitting (130) a data signal to a far-end modem at a data rate of at least 4800 bits per second, the data signal representing a plurality of data packets; timer means for measuring (110, 120) a predetermined amount of time for at least one of the plurality of data frames and for providing an indication of the expiration of the predetermined amount of time; and means responsive to the indication (120) of the expiration of the predetermined amount of time for the at least one of the plurality of data packets for changing the at least 4800 bits per second data rate of the data signal directly to 1200 bits per second.
Claim 11
Dependent Claim
15 words
The apparatus of claim 10 wherein the means for transmitting includes a cellular transceiver. (140)
Claim 12
Dependent Claim
99 words
Apparatus for use in a modem for establishing a data connection with a far-end modem, the apparatus comprising: means for initiating a training sequence (130) with the far-end modem, where the training sequence occurs at a data rate of at least 4800 bits per second; timer means for measuring a predetermined amount of time (110, 120) and for providing a timer signal at the expiration of the predetermined amount of time; and means responsive to the timer signal for directly falling back to a data rate (110) of 1200 bits per second if the training sequence is still active.
Claim 13
Dependent Claim
15 words
The apparatus of claim 12 wherein the means for initiating includes a cellular transceiver. (140)
References Cited (Backward Citations)
EP0039191A2
Cited
US5191583A
Cited
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