Methods and systems for handover using increased probability for fast ranging success
First Claim
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1. A method for synchronizing with a target base station (BS), comprising:
- calculating a relative time difference in radio frequency (RF) signal propagation delays associated with a serving BS and the target BS;
estimating the RF signal propagation delay associated with the target BS based on the calculated relative time difference and a known RF propagation delay associated with the serving BS;
calculating an uplink starting time for the target BS based on a start time of a frame transmission from the target BS, a downlink sub-frame duration, and a downlink to uplink guard time; and
adjusting a starting time of a ranging request (RNG-REQ) transmitted to the target BS, based on the estimated RF signal propagation delay associated with the target BS, wherein the adjustment to the starting time of the RNG-REQ is determined at least in part by deducting the estimated RF signal propagation delay from the calculated uplink starting time for the target BS.
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Abstract
Techniques presented herein disclose handover using increased probability of the fast ranging success. Propagation delay of the RF signal transmitted from an MS to a target BS may be estimated based on a known propagation delay to a current serving BS and a relative difference in propagation delays to the current serving BS and the target BS, for example, as indicated by different receive times of preamble sequences transmitted from the current serving BS and the target BS.
7 Citations
28 Claims
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1. A method for synchronizing with a target base station (BS), comprising:
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calculating a relative time difference in radio frequency (RF) signal propagation delays associated with a serving BS and the target BS; estimating the RF signal propagation delay associated with the target BS based on the calculated relative time difference and a known RF propagation delay associated with the serving BS; calculating an uplink starting time for the target BS based on a start time of a frame transmission from the target BS, a downlink sub-frame duration, and a downlink to uplink guard time; and adjusting a starting time of a ranging request (RNG-REQ) transmitted to the target BS, based on the estimated RF signal propagation delay associated with the target BS, wherein the adjustment to the starting time of the RNG-REQ is determined at least in part by deducting the estimated RF signal propagation delay from the calculated uplink starting time for the target BS. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for synchronizing with a target base station (BS), comprising:
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a processor; memory coupled to the processor; instructions stored in the memory, the instructions being executable by the processor to calculate a relative time difference in radio frequency (RF) signal propagation delays associated with a serving BS and the target BS; estimate the RF signal propagation delay associated with the target BS based on the calculated relative time difference and a known RF propagation delay associated with the serving BS; calculate an uplink starting time for the target BS based on a start time of a frame transmission from the target BS, a downlink sub-frame duration, and a downlink to uplink guard time; and adjusting a starting time of a ranging request (RNG-REQ) transmitted to the target BS, based on the estimated RF signal propagation delay associated with the target BS, wherein the adjustment to the starting time of the RNG-REQ is determined at least in part by deducting the estimated RF signal propagation delay from the calculated uplink starting time for the target BS. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus for synchronizing with a target base station (BS), comprising:
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means for calculating a relative time difference in radio frequency (RF) signal propagation delays associated with a serving BS and the target BS; means for estimating the RF signal propagation delay associated with the target BS based on the calculated relative time difference and a known RF propagation delay associated with the serving BS; means for calculating an uplink starting time for the target BS based on a start time of a frame transmission from the target BS, a downlink sub-frame duration, and a downlink to uplink guard time; and means for adjusting a starting time of a ranging request (RNG-REQ) transmitted to the target BS, based on the estimated RF signal propagation delay associated with the target BS, wherein the adjustment to the starting time of the RNG-REQ is determined at least in part by deducting the estimated RF signal propagation delay from the calculated uplink starting time for the target BS. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A computer-program product for synchronizing with a target base station (BS), comprising a non-transitory computer readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:
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instructions for calculating a relative time difference in radio frequency (RF) signal propagation delays associated with a serving BS and the target BS; instructions for estimating the RF signal propagation delay associated with the target BS based on the calculated relative time difference and a known RF propagation delay associated with the serving BS; instructions for calculating the uplink starting time for the target BS based on a start time of a frame transmission from the target BS, a downlink sub-frame duration, and a downlink to uplink guard time; and instructions for adjusting a starting time of a ranging request (RNG-REQ) transmitted to the target BS, based on the estimated RF signal propagation delay associated with the target BS, wherein the adjustment to the starting time of the RNG-REQ is determined at least in part by deducting the estimated RF signal propagation delay from the calculated uplink starting time for the target BS. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification