Method and apparatus for enhancing call set-up and handoff quality
First Claim
1. A voice frequency selection method comprising the steps of:
- selecting one of a plurality of voice frequencies to carry a cellular communication in a cell;
determining whether an antenna used by the cell for the selected voice frequency is the same as an antenna used by the cell for a reference frequency; and
if not;
making a test broadcast on the selected voice frequency;
measuring received signal strength for the test broadcast;
confirming use of the cell from a sufficient measured test broadcast received signal strength; and
responsive to the confirmation of the cell, establishing the cellular communication over the selected voice frequency.
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Accused Products
Abstract
In a cellular telephone system, mobile station measurements of received signal strength on each reference frequency are made in order to select a cell. At call set-up in or handoff to that cell, a voice frequency is selected by the system to carry the communication. A determination is then made as to whether the antenna used for the reference frequency is the same as that used by the selected voice frequency. From this determination, actions are taken as needed to address concerns over potential differences in broadcast coverage areas for the antennas. For example, an alternate voice frequency using the same antenna as the reference frequency may be chosen. Further, a test broadcast may be made on the selected voice frequency for comparison to the received signal strength on the reference frequency in order to confirm the selection of the cell and use of the selected voice frequency.
25 Citations
21 Claims
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1. A voice frequency selection method comprising the steps of:
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selecting one of a plurality of voice frequencies to carry a cellular communication in a cell; determining whether an antenna used by the cell for the selected voice frequency is the same as an antenna used by the cell for a reference frequency; and if not; making a test broadcast on the selected voice frequency; measuring received signal strength for the test broadcast; confirming use of the cell from a sufficient measured test broadcast received signal strength; and responsive to the confirmation of the cell, establishing the cellular communication over the selected voice frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a cellular telephone system wherein a cell base station includes a first antenna and a second antenna, and wherein the first antenna operates over a reference frequency and the second antenna operates over a plurality of voice frequencies, a voice frequency selection method comprising the steps of:
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selecting one of the plurality of voice frequencies associated with the second antenna to carry a cellular communication; making a test broadcast over the selected voice frequency from the second antenna; measuring received signal strength for the test broadcast; and rejecting the cell base station if the measured test broadcast received signal strength is not substantially equal to a received signal strength measured for a broadcast on the reference frequency from the first antenna. - View Dependent Claims (9, 10, 11, 12)
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- 13. A mobile switching center for use in a cellular telephone system wherein each cell base station includes a plurality of antennas, and wherein a reference frequency and each of a plurality of voice frequencies used by the cell base stations do not necessarily use the same antenna, and wherein each reference frequency and each of the plurality of voice frequencies has an associated antenna identification number, the mobile switching center operating, responsive to a selection of one of the plurality of voice frequencies for carrying a cellular communication in a cell, to compare the antenna identification number for the selected voice frequency to the antenna identification number for the cell reference frequency and, in the event the antenna identification numbers do not match, the mobile switching center further operating to order the transmission over the selected voice frequency of a test broadcast to confirm sufficient received signal strength to support the cellular communication on the selected voice frequency.
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17. A method for evaluating the quality of a selected voice frequency in a cellular telephone system in instances where a base station antenna for the selected voice frequency differs from a base station antenna for a reference frequency of a cell, comprising the steps of:
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making a test broadcast on the selected voice frequency; measuring received signal strength for the test broadcast; and rejecting the selected voice frequency if the measured test broadcast received signal strength is not substantially equal to a received signal strength with respect to the reference frequency. - View Dependent Claims (18, 19, 20, 21)
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Specification