Cellular/WLAN hybrid-terminal handover techniques
First Claim
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1. In a wireless communication device, a method for deciding when to handover a communication device from a wireless communication network to a wireless local area network (WLAN) in real-time, the method comprising:
- measuring samples of WLAN channel quality to generate a plurality of first channel quality measurements;
estimating channel quality of the WLAN for each sample based on the plurality of first channel quality measurements to generate a plurality of first channel quality estimates;
storing the first channel quality estimates prior to a first time instant;
measuring a second sample of WLAN channel quality at the first time instant to generate a second channel quality measurement;
defining a virtual window at the first time instant, wherein the virtual window is defined based on variables comprising a number of samples, the second channel quality measurement, and the plurality of first channel quality estimates; and
using the virtual window to estimate channel quality of the WLAN at the first time instant based on the second channel quality measurement and the plurality of first channel quality estimates to generate a second channel quality estimate.
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Abstract
Real-time handover decision techniques are provided which can utilize prior known system behavior in making a handover decision to avoid averaging delay and hysteresis delay.
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Citations
19 Claims
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1. In a wireless communication device, a method for deciding when to handover a communication device from a wireless communication network to a wireless local area network (WLAN) in real-time, the method comprising:
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measuring samples of WLAN channel quality to generate a plurality of first channel quality measurements; estimating channel quality of the WLAN for each sample based on the plurality of first channel quality measurements to generate a plurality of first channel quality estimates; storing the first channel quality estimates prior to a first time instant; measuring a second sample of WLAN channel quality at the first time instant to generate a second channel quality measurement; defining a virtual window at the first time instant, wherein the virtual window is defined based on variables comprising a number of samples, the second channel quality measurement, and the plurality of first channel quality estimates; and using the virtual window to estimate channel quality of the WLAN at the first time instant based on the second channel quality measurement and the plurality of first channel quality estimates to generate a second channel quality estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A communication device operable in a wireless communication network and a wireless local area network (WLAN) and adapted to make a handover decision in real-time, comprising:
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a measurement module configured to measure samples of WLAN channel quality and generate a plurality of first channel quality measurements based on the samples; a processor configured to estimate channel quality of the WLAN for each sample based on the plurality of first channel quality measurements and to generate a plurality of first channel quality estimates based on the first channel quality measurements; a memory configured to store the first channel quality estimates prior to a first time instant, wherein the measurement module is further configured to measure a second sample of WLAN channel quality at the first time instant to generate a second channel quality measurement based on the second sample, and wherein the processor is configured to define a virtual window at the first time instant, wherein the virtual window is defined based on variables comprising a number of samples, the second channel quality measurement, and the plurality of first channel quality estimates, and wherein the processor is configured to use the virtual window at the first time instant to estimate channel quality of the WLAN at the first time instant based on the second channel quality measurement and the plurality of first channel quality estimates to generate a second channel quality estimate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method in a wireless communication device, comprising:
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storing first channel quality estimates prior to a first time instance, wherein the first channel quality estimates are based on channel quality measurements made prior to a first channel quality measurement; measuring channel quality at the first time instance to generate the first channel quality measurement; defining a virtual window at the first time instance, wherein the virtual window is defined based on variables comprising the first channel quality estimates and the first channel quality measurement; and using the virtual window to generate a second channel quality estimate at the first time instance by estimating channel quality at the first time instance using the first channel quality estimates and the first channel quality measurement to generate the second channel quality estimate at the first time instance. - View Dependent Claims (19)
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Specification