Method for uplink power control in OFDMA TDD system
First Claim
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1. A method for uplink power control in OFDMA (Orthogonal Frequency Division Multiple Access) TDD (Time Division Duplex) system, the method comprising:
- measuring a RSSI (Received Signal Strength Indicator) of downlink signals;
updating a RSSI (Received Signal Strength Indicator) average by calculating a weighted sum of the measured RSSIs and a previous RSSI average; and
carrying out an uplink power control based on the updated RSSI average,wherein weights used for calculating the weighted sum are determined according to at least one of a channel variation rate and a link symmetry,wherein the RSSI average is updated by using the following equation;
RSSIcurrentavg=α
*RSSI+(1−
α
)*RSSIpreviousavg,wherein RSSIcurrentavg and RSSIPpreviousavg are the updated RSSI average and the previous RSSI average, respectively, RSSI is the measured RSSI, and α
is a real number higher than 0 and lower than 1, andwherein α
is set to a first value when the channel variation rate is lower than a predetermined value, α
is set to a second value when the channel variation rate is not lower than the predetermined value, and the first value is higher than the second value.
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Abstract
The present invention relates to a method for uplink power control in an OFDMA TDD system. The method for uplink power control according to the present invention comprises: calculating an RSSI average by using RSSI measured from a downlink signal; and carrying out an uplink power control based on the RSSI average, with the RSSI average being calculated by using a weight that is determined depending on a channel variation rate and link symmetry.
16 Citations
8 Claims
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1. A method for uplink power control in OFDMA (Orthogonal Frequency Division Multiple Access) TDD (Time Division Duplex) system, the method comprising:
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measuring a RSSI (Received Signal Strength Indicator) of downlink signals; updating a RSSI (Received Signal Strength Indicator) average by calculating a weighted sum of the measured RSSIs and a previous RSSI average; and carrying out an uplink power control based on the updated RSSI average, wherein weights used for calculating the weighted sum are determined according to at least one of a channel variation rate and a link symmetry, wherein the RSSI average is updated by using the following equation;
RSSIcurrentavg=α
*RSSI+(1−
α
)*RSSIpreviousavg,wherein RSSIcurrentavg and RSSIPpreviousavg are the updated RSSI average and the previous RSSI average, respectively, RSSI is the measured RSSI, and α
is a real number higher than 0 and lower than 1, andwherein α
is set to a first value when the channel variation rate is lower than a predetermined value, α
is set to a second value when the channel variation rate is not lower than the predetermined value, and the first value is higher than the second value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for uplink power control in OFDMA (Orthogonal Frequency Division Multiple Access) TDD (Time Division Duplex) system, the method comprising:
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measuring a CINR (Carrier to Interference and Noise Ratio) of uplink signals; updating a CINR average by calculating a weighted sum of the measured CINR and a previous CINR average; and carrying out an uplink power control based on the updated CINR average, wherein weights used for calculating the weighted sum are determined according to at least one of a channel variation rate and a link symmetry, wherein the CINR average is updated by using the following equation;
CINRcurrentavg=β
*CINR+(1−
β
)*CINRpreviousavg,wherein CINRcurrentavg and CINRpreviousavg are the updated CINR average and the previous CINR average, respectively, CINR is the measured CINR, and β
is a real number higher than 0 and lower than 1, andwherein β
is set to a first value when the channel variation rate is lower than a predetermined value, β
is set to a second value when the channel variation rate is not lower the predetermined value, and the first value is lower than the second value. - View Dependent Claims (8)
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Specification