Adjustment of period of real-time slow drift correction of alignment of handset's local oscillator for a cordless telephone
First Claim
1. A method of determining a period for an operation between a remote unit and a matching base unit, said method comprising:
- detecting a charging to a remote handset from a base unit; and
adjusting a period between a check of frequency alignment between said remote handset and said base unit based on a battery voltage level in said remote handset.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus to perform a real-time drift correction of a remote handset'"'"'s local oscillator in a digital cordless telephone. The remote handset begins in a standby (sniff) mode. The remote handset periodically wakes from a sleep mode and goes into a normal link verification mode. Once in the link verification mode, the remote handset enters a time division duplexing (TDD) mode and attempts to establish a link with a base unit based on the timing of the TDD data frame. After the remote handset establishes a link with the base unit, the remote handset requests a security word from the base unit. Upon receiving the requested security word, the remote handset determines if the requested security word matches a security word of the remote handset. The remote handset implements a software frequency adjustment of its local oscillator. Once per frame, the remote handset enters a timing recovery state where the current state of the frame is compared with a previous state. When the cumulative timing slip is greater than a designated threshold, a frequency adjustment is made. During this exchange of commands between the remote handset and base unit, the remote handset continuously adjusts its local oscillator to achieve frequency alignment within, e.g., 1 part per million (ppm). Alternatively, frequency alignment may be achieved to a specified value. The period of the frequency alignment can be lengthened (or even suspended) during certain power critical modes to reduce power consumption. For example, the period of the link verify operations (and thus the frequency alignment) can be lengthened or suspended when the remote handset is being quick charged. Moreover, the period of the link verify operations can be adjusted based on a voltage level of the battery in the remote handset.
21 Citations
16 Claims
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1. A method of determining a period for an operation between a remote unit and a matching base unit, said method comprising:
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detecting a charging to a remote handset from a base unit; and
adjusting a period between a check of frequency alignment between said remote handset and said base unit based on a battery voltage level in said remote handset. - View Dependent Claims (2, 3, 4)
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5. Apparatus for determining a period for an operation between a remote unit and a matching base unit, comprising:
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means for detecting a charging to a remote handset from a base unit; and
means for adjusting a period between a check of frequency alignment between said remote handset and said base unit based on a battery voltage level in said remote handset. - View Dependent Claims (6, 7, 8)
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9. A method of adjusting a frequency of an alignment operation between two wireless components that communicate with one another, comprising:
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monitoring a voltage output level of a battery in at least one of said two wireless components; and
decreasing a frequency of said alignment operation between said two wireless components if said monitored voltage output level of said battery falls below a given threshold level. - View Dependent Claims (10, 11, 12)
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13. Apparatus for adjusting a frequency of an alignment operation between two wireless components that communicate with one another, comprising:
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means for monitoring a voltage output level of a battery in at least one of said two wireless components; and
means for decreasing a frequency of said alignment operation between said two wireless components if said monitored voltage output level of said battery falls below a given threshold level. - View Dependent Claims (14, 15, 16)
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Specification