METHOD OF MEASURING CHANNEL QUALITY IN A WIRELESS ACCESS SYSTEM AND APPARATUS FOR SAME

• US 20140086095A1
• Filed: 07/30/2012
• Published: 03/27/2014
• Est. Priority Date: 07/31/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jung, Manyoung, Lim, Suhwan, Yang, Yoonoh, Lee, Sangwook
• Granted Patent: US 9,210,606 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports

Abstract

The present invention relates to a method of measuring channel quality in a wireless access system and an apparatus for same. The method of measuring channel quality in a wireless access system includes the steps of: measuring channel quality using each CRS (cell-specific reference signal) transmitted in 0^th, 4^th, 7^th and 11^th OFDM (orthogonal frequency division multiplexing) symbols in each subframe from a base station; determining whether a channel quality measurement value of the 0^th OFDM symbol is greater by a preset first threshold than an average value of channel quality measurement values of the 4^th, 7^th and 11^th OFDM symbols; and transmitting channel quality information.

Claims

1. A method of allowing a user equipment to measure channel quality in a wireless access system, the method comprising the steps of:

measuring channel quality by using each CRS (cell-specific reference signal) transmitted at 0^th, 4^th, 7^th and 11^th OFDM (orthogonal frequency division multiplexing) symbols of each subframe from a base station;

determining whether a channel quality measurement value at the 0^th OFDM symbol is greater as much as a predetermined first threshold value than an average value of channel quality measurement values of the 4^th, 7^th and 11^th OFDM symbols; and

transmitting channel quality information to the base station,

wherein the channel quality information is an average value of the channel quality measurement values at 0^th, 4^th, 7^th and 11^th OFDM symbols when the channel quality measurement value of the 0^th OFDM symbol is not grater as much as the first threshold value than the average value of channel quality measurement values of the 4^th, 7^th and 11^th OFDM symbols.

2. The method according to claim 1, further comprising the step of determining whether the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is greater than a predetermined second threshold value if the channel quality measurement value at the 0^th OFDM symbol is greater as much as the first threshold value than the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols, wherein the channel quality information is the channel quality measurement value at the 0^th OFDM symbol if the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is smaller than the second threshold value.

3. The method according to claim 2, further comprising the step of determining whether a subframe type of a cell, which measures the channel quality, is a multicast broadcast single frequency network (MBSFN) subframe if the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is greater than the second threshold value, wherein the channel quality information is the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols if the subframe type of the cell, which measures the channel quality, is not the MBSFN subframe.

4. The method according to claim 3, wherein the channel quality information is a value obtained by subtracting the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols from the channel quality measurement value at the 0^th OFDM symbol if the subframe type of the cell, which measures the channel quality, is the MBSFN subframe.

5. The method according to claim 1, wherein the channel quality information is at least any one of reference signal received power (RSRP) and reference signal received quality (RSRQ).

6. A user equipment measuring channel quality in a wireless access system, the user equipment comprising:

a radio frequency (RF) unit configured to transmit and receive a radio signal; and

a processor configured to measure channel quality by using each CRS (cell-specific reference signal) transmitted at 0^th, 4^th, 7^th and 11^th OFDM (orthogonal frequency division multiplexing) symbols of each subframe from a base station, determine whether a channel quality measurement value at the 0^th OFDM symbol is greater as much as a predetermined first threshold value than an average value of channel quality measurement values of the 4^th, 7^th and 11^th OFDM symbols, and transmit channel quality information to the base station,

wherein the channel quality information is an average value of the channel quality measurement values at 0^th, 4^th, 7^th and 11^th OFDM symbols when the channel quality measurement value of the 0^th OFDM symbol is not grater as much as the first threshold value than the average value of channel quality measurement values of the 4^th, 7^th and 11^th OFDM symbols.

7. The user equipment according to claim 6, wherein the processor determines whether the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is greater than a predetermined second threshold value if the channel quality measurement value at the 0^th OFDM symbol is greater as much as the first threshold value than the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols, and the channel quality information is the channel quality measurement value at the 0^th OFDM symbol if the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is smaller than the second threshold value.

8. The user equipment according to claim 7, wherein the processor determines whether a subframe type of a cell, which measures the channel quality, is a multicast broadcast single frequency network (MBSFN) subframe if the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols is greater than the second threshold value, and the channel quality information is the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols if the subframe type of the cell, which measures the channel quality, is not the MBSFN subframe.

9. The user equipment according to claim 8, wherein the channel quality information is a value obtained by subtracting the average value of the channel quality measurement values at the 4^th, 7^th and 11^th OFDM symbols from the channel quality measurement value at the 0^th OFDM symbol if the subframe type of the cell, which measures the channel quality, is the MBSFN subframe.

10. The user equipment according to claim 6, wherein the channel quality information is at least any one of reference signal received power (RSRP) and reference signal received quality (RSRQ).