CA2502844A1 - Method for channel quality prediction for wireless communication systems - Google Patents
Method for channel quality prediction for wireless communication systems Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/262—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account adaptive modulation and coding [AMC] scheme
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
- H04B17/24—Monitoring; Testing of receivers with feedback of measurements to the transmitter
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
- H04L1/0019—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy in which mode-switching is based on a statistical approach
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
- H04L1/0026—Transmission of channel quality indication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/06—TPC algorithms
- H04W52/14—Separate analysis of uplink or downlink
- H04W52/143—Downlink power control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/22—TPC being performed according to specific parameters taking into account previous information or commands
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
- H04W52/241—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
- H04B17/26—Monitoring; Testing of receivers using historical data, averaging values or statistics
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/373—Predicting channel quality or other radio frequency [RF] parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
- H04L1/0025—Transmission of mode-switching indication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/22—TPC being performed according to specific parameters taking into account previous information or commands
- H04W52/223—TPC being performed according to specific parameters taking into account previous information or commands predicting future states of the transmission
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/22—TPC being performed according to specific parameters taking into account previous information or commands
- H04W52/226—TPC being performed according to specific parameters taking into account previous information or commands using past references to control power, e.g. look-up-table
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/22—TPC being performed according to specific parameters taking into account previous information or commands
- H04W52/228—TPC being performed according to specific parameters taking into account previous information or commands using past power values or information
Abstract
A method of improved performance through channel quality prediction for communications systems employing link adaption techniques includes a receiver which makes selective measurements (210) on downlink transmissions, and then stores one or more of the measurements or a channel quality indicator derived therefrom (212). The receiver then retrieves one or more of the past measurements (or the past channel quality estimates themselves), and combines it with current measurements (or the current channel quality estimate), to predict what the channel quality will be at some future time and derive a predictive channel quality indicator (CQI). This predictive CQI, derived from both current channel measurements and at least one past channel measurement, is then sent to the transmitter for use in updating transmission parameters (220).
Description
2 PCT/US2003/034725 [0001] METHOD FOR CHANNEL QUALITY
PREDICTION FOR WIRELESS COMMUNICATION SYSTEMS
[0002] FIELD OF INVENTION
PREDICTION FOR WIRELESS COMMUNICATION SYSTEMS
[0002] FIELD OF INVENTION
[0003] The present invention genes ally r elates to wireless communication systems. More particularly, the present invention is a method employed by a wireless communication system for improved channel quality indication in dynamic link adaption.
[0004] BACKGROUND
[0005] Various algorithms are currently used by present wireless communication systems for estimating channel quality at a wireless receiver.
These algorithms are employed, for example, in systems using the Third Generation Partnership Project (3GPP) High Chip Rate Time Division Duplex (TDD) mode, the 3GPP Low Chip Rate TDD mode, the 3GPP Frequency Division Duplex (FDD) mode, the time division - synchronous code division multiple access (TD-SCDMA) standard, and High Speed Downlink Packet Access (HSDPA) extensions of the aforementioned systems. The quality estimates may be used for transmit power control, in- and out-of synchronization decisions, radio link failure decisions, and channel quality indicators (CQIs) to support dynamic link adaptation, (e.g., adaptive modulation and coding (AMC)) techniques.
These algorithms are employed, for example, in systems using the Third Generation Partnership Project (3GPP) High Chip Rate Time Division Duplex (TDD) mode, the 3GPP Low Chip Rate TDD mode, the 3GPP Frequency Division Duplex (FDD) mode, the time division - synchronous code division multiple access (TD-SCDMA) standard, and High Speed Downlink Packet Access (HSDPA) extensions of the aforementioned systems. The quality estimates may be used for transmit power control, in- and out-of synchronization decisions, radio link failure decisions, and channel quality indicators (CQIs) to support dynamic link adaptation, (e.g., adaptive modulation and coding (AMC)) techniques.
[0006] In the TDD mode for instance, the quality indicator, referred to as CQI, sent by the User Equipment (UE) on the high speed-shared information channel (HS-SIGH) is a recommended Transport Format Resource Combination (TFRC). In general, the TFRC refers to the possible transport block sizes, modulation schemes, and any other link adaptation parameters available. The recommended TFRC is usually based on the signal most recently received by the UE.
[0007] Regardless of whether or not the communication system is a 3GPP
system, the CQI could represent a recommended Transport Block Size, modulation format, number of codes, power offsets, or any one of a number of IF mu. ..
different types of link adaptation parameters. These CQIs are derived by a receiver and signaled to a transmitter to set the transmission parameters for a subsequent transmission.
system, the CQI could represent a recommended Transport Block Size, modulation format, number of codes, power offsets, or any one of a number of IF mu. ..
different types of link adaptation parameters. These CQIs are derived by a receiver and signaled to a transmitter to set the transmission parameters for a subsequent transmission.
[0008] The CQI typically provides either specific link adaptation information, such as a recommended coding and modulation scheme for the AMC
function, or provides one or more general quality indicators which are subsequently used to base the selection of appropriate transmission parameters.
function, or provides one or more general quality indicators which are subsequently used to base the selection of appropriate transmission parameters.
[0009] If the CQI is not accurate, the selected modulation and coding scheme (or other transmission parameters) will be suboptimal. Overestimating channel quality can cause the UE and Node B to continue attempting to use a modulation and coding scheme when reception quality is too poor to justify their continued use. Underestimation of channel quality may lead to excessive transmission power and inefficient use of radio recourses or, in the case of in- and out-of sync processing, ultimately a premature declaration of radio link failure and release of radio resources. Thus, a call may be dropped without cause.
Excessive transmission power will, in turn, lead to a system-level throughput loss since interference in other cells may increase needlessly. Accordingly, inaccurate channel quality estimation reduces throughput, wastes transmit power, and increases interference to other cells.
Excessive transmission power will, in turn, lead to a system-level throughput loss since interference in other cells may increase needlessly. Accordingly, inaccurate channel quality estimation reduces throughput, wastes transmit power, and increases interference to other cells.
[0010] A shortcoming of prior art channel estimation techniques is that since the techniques estimate channel quality at a receiver, they do not provide sufficiently accurate estimates of channel quality at the transmitter at the time of the subsequent transmission. Referring to Figure 1, a prior art CQI
generation and reporting procedure 100 between a UE and a Node B is shown. The Node B
transmits a message on a downlink (DL) control channel (step 102), informing the UE which resources have been allocated to the UE for the next associated DL
data transmission. The UE receives the control message regarding the allocation of resources and awaits the receipt of the DL data transmission (step 104).
generation and reporting procedure 100 between a UE and a Node B is shown. The Node B
transmits a message on a downlink (DL) control channel (step 102), informing the UE which resources have been allocated to the UE for the next associated DL
data transmission. The UE receives the control message regarding the allocation of resources and awaits the receipt of the DL data transmission (step 104).
[0011] The Node B sends the associated DL data transmission (step 106).
The UE reads the DL data transmission (step 108) and makes selective quality measurements (step 110). Using the measurements from step 110, the UE
_2_ derives a CQI (step 112) that it estimates would provide the highest throughput, while still meeting other possibly specified requirements, such as a block error rate (BLER).
The UE reads the DL data transmission (step 108) and makes selective quality measurements (step 110). Using the measurements from step 110, the UE
_2_ derives a CQI (step 112) that it estimates would provide the highest throughput, while still meeting other possibly specified requirements, such as a block error rate (BLER).
[0012] The UE then reports the most recently derived CQI to the Node B in the next available UL control channel (step 114). The Node B receives the CQI
(step 116) and then uses the CQI to set the transmission parameters for the next data transmission (step 118).
(step 116) and then uses the CQI to set the transmission parameters for the next data transmission (step 118).
[0013] There are drawbacks with the current method of providing CQI
feedback. For example, the current 3GPP specification does not set a specific time limit on how long the UE may take to derive the CQI. This could take an inordinately long time. It is, however, required (and desirable) that once the CQI
is derived from the given data transmission, it is reported in the next available UL control channel. This minimizes the delay in getting the CQI information to the Node B. However, even if the delay in getting the CQI information from the UE to the Node B is minimized, the delay is not eliminated.
feedback. For example, the current 3GPP specification does not set a specific time limit on how long the UE may take to derive the CQI. This could take an inordinately long time. It is, however, required (and desirable) that once the CQI
is derived from the given data transmission, it is reported in the next available UL control channel. This minimizes the delay in getting the CQI information to the Node B. However, even if the delay in getting the CQI information from the UE to the Node B is minimized, the delay is not eliminated.
[0014] As shown in the example timing diagram of Figure 2, there is a CQI
measurement period on one or more DL transmissions, during which the UE
makes selective measurements on the DL transmission. As shown, the measurements may be performed on a DL data channel, a DL pilot channel, or a combination of both the DL data and pilot channels. After the measurements are performed, the CQI is calculated; this is shown at time tl. Although the delay is minimized by reporting the CQI to the Node B at the next available UL
transmission (shown at time t2), there is additional delay until the subsequent use by the Node B of the CQI (shown at time t3) to set the parameters for the next downlink data transmission.
measurement period on one or more DL transmissions, during which the UE
makes selective measurements on the DL transmission. As shown, the measurements may be performed on a DL data channel, a DL pilot channel, or a combination of both the DL data and pilot channels. After the measurements are performed, the CQI is calculated; this is shown at time tl. Although the delay is minimized by reporting the CQI to the Node B at the next available UL
transmission (shown at time t2), there is additional delay until the subsequent use by the Node B of the CQI (shown at time t3) to set the parameters for the next downlink data transmission.
[0015] The delay (graphically designated as A) between the completion of the measurements upon which the CQI is based (at time tl)and the subsequent use by the Node B to set the associated transmission parameters at time t3 results in a CQI that is not accurate by the time it is used by the Node B.
The greater this delay, the less accurate the CQI becomes. As the CQI becomes less accurate, the DL channel quality will ultimately suffer since the transmission parameters will be based on a CQI that does not accurately reflect the true channel conditions. In essence, the prior art methods of CQI determination reflect the past conditions of the channel.
The greater this delay, the less accurate the CQI becomes. As the CQI becomes less accurate, the DL channel quality will ultimately suffer since the transmission parameters will be based on a CQI that does not accurately reflect the true channel conditions. In essence, the prior art methods of CQI determination reflect the past conditions of the channel.
[0016] It would be desirable to provide a method of channel quality determination without the severe disadvantages of known prior art systems.
[0017] SUMMARY
[001] The present invention provides a method of improved performance through channel quality prediction for communications systems employing link adaption techniques. A receiver makes selective measurements on DL
transmissions and then stores one or more of the measurements or a channel quality indicator derived therefrom. The receiver then retrieves one or more of the past measurements (or the past channel quality estimates themselves), and combines it with current measurements (or the current channel quality estimate), to predict what the channel quality will be at some future time to derive a predictive channel quality indicator (CQI). This predictive CQI, derived from both current channel measurements and at least one past channel measurement, is then sent to the transmitter for use in updating transmission parameters.
[0019] BRIEF DESCRIPTION OF THE DR,AWING(S) [0020] A more detailed understanding of the invention may be had from the following description of preferred embodiments, given by way of example and to be understood in conjunction with the accompanying drawing wherein:
[0021] Figure 1 is a flow diagram of a method for CQI generation and reporting in accordance with the prior art.
[0022] Figure 2 is a timing diagram showing the delay associated with the prior art CQI reporting method of Figure 1.
[0023] Figure 3 is a predictive CQI generation and reporting method in accordance with a preferred embodiment of the present invention.
[0024] Figure 4 is a predictive CQI generation and reporting method in accordance with a first alternative embodiment of the present invention.
[0025] Figure 5 is a predictive CQI generation and reporting method in accordance with a second alternative embodiment of the present invention.
[0026] Figure 6 is a timing diagram showing the elimination of the inherent CQI delay associated with the embodiments of the present invention shown in Figures 3 and 4.
[0027] Figure 7 is a graph showing the distribution of the difference between the CQI generation and reporting process in accordance with the prior art and the predictive CQI generation and reporting process in accordance with the present invention.
[0028] This application uses the following acronyms:
3GPP Third Generation Partnership Project AMC Adaptive Modulation and Coding CDMA Code Division Multiple Access CQI Channel Quality Indicator DL Downlink FDD Frequency Division Duplex HSDPA High Speed Downlink Packet Access HS-DPCCH Shared Information Channel for HS-DSC (FDD) HS-SIGH High Speed Shared Information Channel for HS-DSCH (TDD) SIR Signal-to-Interference Ratio TDD Time Division Duplex TD-SCDMA Time Division-Synchronous Code Division Multiple Access TFRC Transport Format Resource Combination UE User Equipment UL Uplink [0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS) [0030] The present invention provides an improved method of channel quality prediction without the disadvantages of the prior art.
[0031] Hereafter, a wireless transmit/receive unit (WTRU) includes but is not limited to a UE, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. Each of these terms may be used interchangeably herein. When referred to hereafter, a Node B includes but is not limited to a base station, site controller, access point or any other type of interfacing device in a wireless environment. Each of these terms may be used interchangeably herein.
[0032] It is to be noted that the present invention is applicable to TDD, FDD, TD-SCDMA, CDMA 2000, and other modes and types of transmissions without exception. More generally, the present invention is applicable to any communication system employing a scheme which monitors channel quality and adapts the transmission parameters of subsequent transmissions based upon the channel quality, such as AMC or other forms of radio link adaptation.
[0033] In accordance with the present invention, the CQI is a predictive indicator of the quality of future channel conditions. While either a Node B
or WTRU may perform such predictions, the present invention will be described hereinafter as being performed at the WTRU. Additionally, although the invention will be described as a receiver performing measurements and deriving the CQI, it is equally possible for the receiver to perform the measurements and transmit the measurements to the transmitter which then derives the CQI. It would also be understood by those of skill in the art that the present invention is equally applicable to the uplink (UL) or DL transmissions, such as in the case of link adaptation in the UL, where the roles of the WTRU and the Node B as described hereinafter will be reversed.
[0034] In a slotted system where the transmission bursts may span several time slots, interference levels in these time slots can vary greatly. The present invention recognizes that channel fading conditions may change substantially from slot to slot. By allowing (but not requiring) CQI prediction on a per slot basis, the prediction of channel quality can be improved. The channel quality reported to the transmitter can therfore be made more accurate, compared to the prior art situations.
[0035] Referring to Figure 3, a procedure 200 for generating and reporting a CQI in accordance with the present invention is shown. The procedure 200 is initiated by the Node B transmitting a downlink control message regarding the allocation of resources to the WTRU (step 202). The WTRU receives the control message regarding the allocation of resources on the downlink control channel (step 204). ' The message informs the WTRU of the timing of a subsequent data transmission, and of the transmission parameters of the subsequent data transmission (for example, the type ofmodulation, coding, etc.). The Node B
then sends a downlink data transmission to the WTRU (step 206) which is received by the WTRU (step 20~). The WTRU makes selective CQI measurements regarding the downlink data transmission (step 210), derives the current CQI (step 212), and then determines a predictive CQI (step 214). As part of step 214, the WTRU
stores one or more of the CQI measurements and/or the CQI for later use in determining the predictive CQI. Additionally, it should be noted that it is not necessary to derive a current CQI in order to determine the predictive CQI.
Thus, step 212 could be considered optional in this embodiment. For example, past CQI measurements may be combined with current CQI measurements to derive a predictive CQI.
[0036] The predictive CQI is derived from both current measurements and at least one past measurement. The WTRU retrieves one or more of the past CQI
measurements (or the past CQI themselves), and combines it with the current CQI measurement (or current CQI), to predict the quality of future channel conditions.
_7_ [0037] In one embodiment of the present invention, the prediction method used in step 214 to derive the predictive CQI is the Linear Prediction method.
This is a well known mathematical technique for predicting future values based upon the combination of current and past information. The Linear Prediction method minimizes the prediction error in the least squares sense. In a preferred embodiment, the signal-to-interference ratio (SIR) expressed in dB is the quantity being predicted. However, other factors may be included, such as prediction of signal power and noise power separately. Other prediction methods can be used, and may be selected with both performance and minimzing complexity in mind.
[0038] After the predictive CQI is derived at step 214, the WTRU reports the predictive CQI to the Node B (step 216) and the Node B receives the predictive CQI at step 218. The Node B then uses the predictive CQI to set transmission parameters for the next transmission (step 220).
[0039] It should be understood by those of skill in the art that certain steps may be combined depending upon the specific implementation of this method.
For example, as shown in an alternative embodiment of a method 400 of the present invention in Figure 4, steps 210, 212, and 214 may be combined into a single step 408 for determining the predictive CQI. All other steps in Figure remain the same as the steps described with reference to Figure 3.
[0040] Additionally, as shown in Figure 5, steps 202 and 204 need not be part of the procedure 500, whereby the WTRU automatically receives the DL
data transmission without a prior DL control message.
[0041] Whether the specific process for determining the CQI is set forth in separate steps 210-214 as shown in Figure 3 or a single step 408 as shown in Figure 4, it would be understood by those of skill in the art that, in contrast to the prior art methods of CQI determination which reflect the past conditions of a communication channel, the present invention derives a predictive CQI which pr edicts the future conditions of a communication channel. The present invention makes current measurements, but predicts and reports to the Node B a predictive CQI which esitmates future channel conditions. As aforementioned, _g_ this predictive CQI is derived from both a current CQI measurement or current CQI derived therefrom and at least one past CQI measurement or past CQI
derived therefrom that has been stored. The predictive CQI estimates the quality of the channel conditions closer to the time the Node B is ready to transmit.
[0042] Although the CQI is shown as being derived from only a single data channel, the UE may use the DL data transmission (of step 206), any available pilot signals, or combinations of both to derive the CQI.
[0043] In accordance with the preferred method 200 of the present invention, the predictive CQI will be much more likely to reflect the actual channel conditions that the Node B will experience when it is ready to send another transmission, rather than a CQI measurement that is reflective of a past transmission, as shown in Figures I. and 2.
[0044] Referring to Figure 6, although the WTRU makes the current CQI
measurement at the same time as the prior art scheme (at time tl), and then combines it with the prior CQI measurements for transmission to the Node B at the same time as the prior art scheme (at time t~), the WTRU in accordance with the present invention predicts what the channel condition will be at time t3.
In the example illustrated in Figure 6, the "apparent" CQI delay vanishes since the CQI has been predicted to line-up in time with the DL data channel.
Accordingly, when the Node B is ready to transmit the DL data (at time t3), there is no delay (shown as B=0), since the predictive CQI that was sent is a CQI
that was predicted at time t3.
[0045] Even if there is a delay between the completion of the CQI
measurements (at time tl) and the use of the measurement by the Node B, this delay will be shorter than the delay A shown in Figure 2. By using available past information about the channel quality history, the reported CQI can be computed to reflect the channel quality that will exist at the time of the next DL data transmission, thereby making the selected code rate, modulation type and other link adaption parameters more accurate.
[0046] Although Figure 6 shows the CQT measurements being performed on both the DL data channel and the DL pilot channel, it would be understood by _g_ those of skill in the art that the CQI measurements may be performed solely on a DL data channel, solely on a DL pilot channel, or performed on a combination of both the DL data and pilot channels.
[0047] Although there will also be an associated error in the predictive CQI
measurement (since it is predicted and not actual), this error is likely to be smaller than the prior art method of sending an outdated CQI measurement.
Figure 7 shows how using the prediction scheme used in accordance with the present invention can be employed to improve the reporting accuracy of channel quality conditions at the time of the actual transmission, thereby improving the perference of any dynamic link adaption systems. In Figure 7, a distribution of the difference between the SIR measured and the SIR at the time the SIR is used is shown. In this example, the delay is 10 msec.
[0048] There are two probability distribution curves shown, one for the prior art method of sending a CQI measurement based on past channel conditions, illustrated as curve A, and the second for the current method of sending a predictive CQI measurement based upon a future channel condition, illustrated as curve B. With the present invention (curve B), there is a higher likelihood that an associated error will be smaller, and a lower likelihood that an associated error will be larger, than with the curve A of the prior art method.
The , distribution for the prediction signal in accordance with the present invention is more concentrated near zero error than the delayed signal of the prior art, indicating that the CQI reporting errors are smaller when using predictive CQI.
[0049] Although the present invention has been described in detail, it is to be understood that the invention is not limited thereto, and that various changes can be made therein without departing from the scope of the invention, which is defined by the attached claims.
[001] The present invention provides a method of improved performance through channel quality prediction for communications systems employing link adaption techniques. A receiver makes selective measurements on DL
transmissions and then stores one or more of the measurements or a channel quality indicator derived therefrom. The receiver then retrieves one or more of the past measurements (or the past channel quality estimates themselves), and combines it with current measurements (or the current channel quality estimate), to predict what the channel quality will be at some future time to derive a predictive channel quality indicator (CQI). This predictive CQI, derived from both current channel measurements and at least one past channel measurement, is then sent to the transmitter for use in updating transmission parameters.
[0019] BRIEF DESCRIPTION OF THE DR,AWING(S) [0020] A more detailed understanding of the invention may be had from the following description of preferred embodiments, given by way of example and to be understood in conjunction with the accompanying drawing wherein:
[0021] Figure 1 is a flow diagram of a method for CQI generation and reporting in accordance with the prior art.
[0022] Figure 2 is a timing diagram showing the delay associated with the prior art CQI reporting method of Figure 1.
[0023] Figure 3 is a predictive CQI generation and reporting method in accordance with a preferred embodiment of the present invention.
[0024] Figure 4 is a predictive CQI generation and reporting method in accordance with a first alternative embodiment of the present invention.
[0025] Figure 5 is a predictive CQI generation and reporting method in accordance with a second alternative embodiment of the present invention.
[0026] Figure 6 is a timing diagram showing the elimination of the inherent CQI delay associated with the embodiments of the present invention shown in Figures 3 and 4.
[0027] Figure 7 is a graph showing the distribution of the difference between the CQI generation and reporting process in accordance with the prior art and the predictive CQI generation and reporting process in accordance with the present invention.
[0028] This application uses the following acronyms:
3GPP Third Generation Partnership Project AMC Adaptive Modulation and Coding CDMA Code Division Multiple Access CQI Channel Quality Indicator DL Downlink FDD Frequency Division Duplex HSDPA High Speed Downlink Packet Access HS-DPCCH Shared Information Channel for HS-DSC (FDD) HS-SIGH High Speed Shared Information Channel for HS-DSCH (TDD) SIR Signal-to-Interference Ratio TDD Time Division Duplex TD-SCDMA Time Division-Synchronous Code Division Multiple Access TFRC Transport Format Resource Combination UE User Equipment UL Uplink [0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS) [0030] The present invention provides an improved method of channel quality prediction without the disadvantages of the prior art.
[0031] Hereafter, a wireless transmit/receive unit (WTRU) includes but is not limited to a UE, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. Each of these terms may be used interchangeably herein. When referred to hereafter, a Node B includes but is not limited to a base station, site controller, access point or any other type of interfacing device in a wireless environment. Each of these terms may be used interchangeably herein.
[0032] It is to be noted that the present invention is applicable to TDD, FDD, TD-SCDMA, CDMA 2000, and other modes and types of transmissions without exception. More generally, the present invention is applicable to any communication system employing a scheme which monitors channel quality and adapts the transmission parameters of subsequent transmissions based upon the channel quality, such as AMC or other forms of radio link adaptation.
[0033] In accordance with the present invention, the CQI is a predictive indicator of the quality of future channel conditions. While either a Node B
or WTRU may perform such predictions, the present invention will be described hereinafter as being performed at the WTRU. Additionally, although the invention will be described as a receiver performing measurements and deriving the CQI, it is equally possible for the receiver to perform the measurements and transmit the measurements to the transmitter which then derives the CQI. It would also be understood by those of skill in the art that the present invention is equally applicable to the uplink (UL) or DL transmissions, such as in the case of link adaptation in the UL, where the roles of the WTRU and the Node B as described hereinafter will be reversed.
[0034] In a slotted system where the transmission bursts may span several time slots, interference levels in these time slots can vary greatly. The present invention recognizes that channel fading conditions may change substantially from slot to slot. By allowing (but not requiring) CQI prediction on a per slot basis, the prediction of channel quality can be improved. The channel quality reported to the transmitter can therfore be made more accurate, compared to the prior art situations.
[0035] Referring to Figure 3, a procedure 200 for generating and reporting a CQI in accordance with the present invention is shown. The procedure 200 is initiated by the Node B transmitting a downlink control message regarding the allocation of resources to the WTRU (step 202). The WTRU receives the control message regarding the allocation of resources on the downlink control channel (step 204). ' The message informs the WTRU of the timing of a subsequent data transmission, and of the transmission parameters of the subsequent data transmission (for example, the type ofmodulation, coding, etc.). The Node B
then sends a downlink data transmission to the WTRU (step 206) which is received by the WTRU (step 20~). The WTRU makes selective CQI measurements regarding the downlink data transmission (step 210), derives the current CQI (step 212), and then determines a predictive CQI (step 214). As part of step 214, the WTRU
stores one or more of the CQI measurements and/or the CQI for later use in determining the predictive CQI. Additionally, it should be noted that it is not necessary to derive a current CQI in order to determine the predictive CQI.
Thus, step 212 could be considered optional in this embodiment. For example, past CQI measurements may be combined with current CQI measurements to derive a predictive CQI.
[0036] The predictive CQI is derived from both current measurements and at least one past measurement. The WTRU retrieves one or more of the past CQI
measurements (or the past CQI themselves), and combines it with the current CQI measurement (or current CQI), to predict the quality of future channel conditions.
_7_ [0037] In one embodiment of the present invention, the prediction method used in step 214 to derive the predictive CQI is the Linear Prediction method.
This is a well known mathematical technique for predicting future values based upon the combination of current and past information. The Linear Prediction method minimizes the prediction error in the least squares sense. In a preferred embodiment, the signal-to-interference ratio (SIR) expressed in dB is the quantity being predicted. However, other factors may be included, such as prediction of signal power and noise power separately. Other prediction methods can be used, and may be selected with both performance and minimzing complexity in mind.
[0038] After the predictive CQI is derived at step 214, the WTRU reports the predictive CQI to the Node B (step 216) and the Node B receives the predictive CQI at step 218. The Node B then uses the predictive CQI to set transmission parameters for the next transmission (step 220).
[0039] It should be understood by those of skill in the art that certain steps may be combined depending upon the specific implementation of this method.
For example, as shown in an alternative embodiment of a method 400 of the present invention in Figure 4, steps 210, 212, and 214 may be combined into a single step 408 for determining the predictive CQI. All other steps in Figure remain the same as the steps described with reference to Figure 3.
[0040] Additionally, as shown in Figure 5, steps 202 and 204 need not be part of the procedure 500, whereby the WTRU automatically receives the DL
data transmission without a prior DL control message.
[0041] Whether the specific process for determining the CQI is set forth in separate steps 210-214 as shown in Figure 3 or a single step 408 as shown in Figure 4, it would be understood by those of skill in the art that, in contrast to the prior art methods of CQI determination which reflect the past conditions of a communication channel, the present invention derives a predictive CQI which pr edicts the future conditions of a communication channel. The present invention makes current measurements, but predicts and reports to the Node B a predictive CQI which esitmates future channel conditions. As aforementioned, _g_ this predictive CQI is derived from both a current CQI measurement or current CQI derived therefrom and at least one past CQI measurement or past CQI
derived therefrom that has been stored. The predictive CQI estimates the quality of the channel conditions closer to the time the Node B is ready to transmit.
[0042] Although the CQI is shown as being derived from only a single data channel, the UE may use the DL data transmission (of step 206), any available pilot signals, or combinations of both to derive the CQI.
[0043] In accordance with the preferred method 200 of the present invention, the predictive CQI will be much more likely to reflect the actual channel conditions that the Node B will experience when it is ready to send another transmission, rather than a CQI measurement that is reflective of a past transmission, as shown in Figures I. and 2.
[0044] Referring to Figure 6, although the WTRU makes the current CQI
measurement at the same time as the prior art scheme (at time tl), and then combines it with the prior CQI measurements for transmission to the Node B at the same time as the prior art scheme (at time t~), the WTRU in accordance with the present invention predicts what the channel condition will be at time t3.
In the example illustrated in Figure 6, the "apparent" CQI delay vanishes since the CQI has been predicted to line-up in time with the DL data channel.
Accordingly, when the Node B is ready to transmit the DL data (at time t3), there is no delay (shown as B=0), since the predictive CQI that was sent is a CQI
that was predicted at time t3.
[0045] Even if there is a delay between the completion of the CQI
measurements (at time tl) and the use of the measurement by the Node B, this delay will be shorter than the delay A shown in Figure 2. By using available past information about the channel quality history, the reported CQI can be computed to reflect the channel quality that will exist at the time of the next DL data transmission, thereby making the selected code rate, modulation type and other link adaption parameters more accurate.
[0046] Although Figure 6 shows the CQT measurements being performed on both the DL data channel and the DL pilot channel, it would be understood by _g_ those of skill in the art that the CQI measurements may be performed solely on a DL data channel, solely on a DL pilot channel, or performed on a combination of both the DL data and pilot channels.
[0047] Although there will also be an associated error in the predictive CQI
measurement (since it is predicted and not actual), this error is likely to be smaller than the prior art method of sending an outdated CQI measurement.
Figure 7 shows how using the prediction scheme used in accordance with the present invention can be employed to improve the reporting accuracy of channel quality conditions at the time of the actual transmission, thereby improving the perference of any dynamic link adaption systems. In Figure 7, a distribution of the difference between the SIR measured and the SIR at the time the SIR is used is shown. In this example, the delay is 10 msec.
[0048] There are two probability distribution curves shown, one for the prior art method of sending a CQI measurement based on past channel conditions, illustrated as curve A, and the second for the current method of sending a predictive CQI measurement based upon a future channel condition, illustrated as curve B. With the present invention (curve B), there is a higher likelihood that an associated error will be smaller, and a lower likelihood that an associated error will be larger, than with the curve A of the prior art method.
The , distribution for the prediction signal in accordance with the present invention is more concentrated near zero error than the delayed signal of the prior art, indicating that the CQI reporting errors are smaller when using predictive CQI.
[0049] Although the present invention has been described in detail, it is to be understood that the invention is not limited thereto, and that various changes can be made therein without departing from the scope of the invention, which is defined by the attached claims.
Claims (31)
1. A method for providing feedback regarding the quality of a communication channel which is transmitted between a transmitter and a receiver; the method comprising:
transmitting a control communication from said transmitter to said receiver, said control communication including information regarding the allocation of resources in a subsequent downlink communication;
receiving at said receiver said control communication and awaiting said downlink communication;
transmitting from said transmitter said downlink communication over a downlink channel;
receiving at said receiver said downlink communication;
performing at said receiver at least one current measurement on said downlink communication to determine the current quality of said downlink channel;
deriving, based on said performing step, a channel quality indication (CQI)9 and transmitting said CQI from said receiver to said transmitter; whereby said deriving step estimates the future quality of said downlink channel to derive said CQI.
transmitting a control communication from said transmitter to said receiver, said control communication including information regarding the allocation of resources in a subsequent downlink communication;
receiving at said receiver said control communication and awaiting said downlink communication;
transmitting from said transmitter said downlink communication over a downlink channel;
receiving at said receiver said downlink communication;
performing at said receiver at least one current measurement on said downlink communication to determine the current quality of said downlink channel;
deriving, based on said performing step, a channel quality indication (CQI)9 and transmitting said CQI from said receiver to said transmitter; whereby said deriving step estimates the future quality of said downlink channel to derive said CQI.
2. The method of claim 1, further including storing said at least one current measurement.
3. The method of claim 2, wherein said deriving step further includes retrieving at least one stored measurement and utilizing said at least one stored measurement and said at least one current measurement to derive said CQI.
4. The method of claim 1, further including storing said CQI.
5. The method of claim 1, wherein said deriving step utilizes a linear predictive algorithm to derive said CQI.
6. The method of claim 1 wherein said downlink communication comprises at least one data communication.
7. The method of claim 1, wherein said downlink communication comprises at least one pilot communication.
8. The method of claim 1 wherein said downlink channel comprises a plurality of downlink channels on which said measurements are performed.
9. The method of claim 8 wherein said plurality of downlink channels includes at least one data channel on which said measurements are performed.
10. The method of claim 8 wherein said plurality of downlink channels includes at least one pilot channel on which said measurements are performed.
11. The method of claim 8 wherein said plurality of channels includes at least one pilot channel and at least one data channel on which said measurements are performed.
12. A method for providing channel quality measurements on a downlink communication channel transmitted from a receiver to a transmitter;
the method comprising:
monitoring said downlink communication channel at said receiver;
performing at least one current measurement on said downlink communication channel;
deriving an indicator of the quality of the downlink communication channel; and transmitting said indicator to said transmitter;
whereby said deriving step predicts the future quality of the downlink communication channel.
the method comprising:
monitoring said downlink communication channel at said receiver;
performing at least one current measurement on said downlink communication channel;
deriving an indicator of the quality of the downlink communication channel; and transmitting said indicator to said transmitter;
whereby said deriving step predicts the future quality of the downlink communication channel.
13. The method of claim 12, further including storing said at least one current measurement.
14. The method of claim 13, wherein said deriving step further includes retrieving at least one stored measurement and utilizing said at least one stored measurement and said at least one current measurement to derive said CQI.
15. The method of claim 12, further including storing said CQI.
16. The method of claim 12, wherein said deriving step utilizes a linear predictive algorithm to derive said CQI.
17. The method of claim 12 wherein said downlink communication channel comprises at least one data channel.
18. The method of claim 12, wherein said downlink communication channel comprises at least one pilot channel.
19. The method of claim 12 wherein said downlink communication channel comprises a plurality of downlink channels on which said measurements are performed.
20. The method of claim 19 wherein said plurality of downlink channels includes at least one data channel on which said measurements are performed.
21. The method of claim 19 wherein said plurality of downlink channels includes at least one pilot channel on which said measurements are performed.
22. The method of claim 19 wherein said plurality of downlink channels includes at least one pilot channel and at least one data channel on which said measurements are performed.
23. A method for providing channel quality measurements on a downlink communication channel transmitted from a receiver to a transmitter;
the method comprising:
monitoring said communication channel at said receiver;
performing at least one current measurement on said communication channel;
deriving an indicator of the quality of the communication channel; and transmitting said indicator to said transmitter;
whereby said deriving step predicts the future quality of the communication channel.
the method comprising:
monitoring said communication channel at said receiver;
performing at least one current measurement on said communication channel;
deriving an indicator of the quality of the communication channel; and transmitting said indicator to said transmitter;
whereby said deriving step predicts the future quality of the communication channel.
24. The method of claim 24, further including storing said at least one current measurement.
25. The method of claim 24, wherein said deriving step further includes retrieving at least one stored measurement and utilizing said at least one stored measurement and said at least one current measurement to derive said CQI.
26. The method of claim 23, further including storing said CQI.
27. The method of claim 23, wherein said deriving step utilizes a linear predictive algorithm to derive said CQI.
28. The method of claim 23 wherein said communication channel comprises a plurality of channels on which said measurements are performed.
29. The method of claim 28 wherein said plurality of channels includes at least one data channel on which said measurements are performed.
30. The method of claim 28 wherein said plurality of channels includes at least one pilot channel on which said measurements are performed.
31. The method of claim 28 wherein said plurality of downlink channels includes at least one pilot channel and at least one data channel on which said measurements are performed.
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Families Citing this family (125)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4150002B2 (en) * | 2003-04-25 | 2008-09-17 | 富士通株式会社 | Transmitting apparatus and data allocation method for assigning data of receiving apparatus selected from a plurality of receiving apparatuses to shared channel |
US8018902B2 (en) * | 2003-06-06 | 2011-09-13 | Telefonaktiebolaget L M Ericsson (Publ) | Methods and apparatus for channel quality indicator determination |
US7380028B2 (en) * | 2003-06-13 | 2008-05-27 | Microsoft Corporation | Robust delivery of video data |
JP4069034B2 (en) * | 2003-07-31 | 2008-03-26 | 松下電器産業株式会社 | Wireless transmission device, wireless reception device, wireless communication system, wireless transmission method, and wireless reception method |
GB2405289B (en) * | 2003-08-20 | 2006-10-25 | Ipwireless Inc | Method,base station,remote station and system for HSDPA communication |
FI20031383A0 (en) * | 2003-09-25 | 2003-09-25 | Nokia Corp | Method and packet radio system to control the adaptation of a transmission connection |
KR100612655B1 (en) * | 2004-01-02 | 2006-08-16 | 한국전자통신연구원 | A method for traffic indication and channel adaptation for the sleep mode terminals, and an apparatus therefore |
WO2005081439A1 (en) * | 2004-02-13 | 2005-09-01 | Neocific, Inc. | Methods and apparatus for multi-carrier communication systems with adaptive transmission and feedback |
KR20050078635A (en) * | 2004-02-02 | 2005-08-05 | 한국전자통신연구원 | A method for requesting and reporting channel quality information in wireless system and apparatus thereof |
JP4421935B2 (en) * | 2004-04-30 | 2010-02-24 | 株式会社エヌ・ティ・ティ・ドコモ | Radio base station apparatus and radio communication control method |
CN1965513B (en) | 2004-05-01 | 2014-11-26 | 桥扬科技有限公司 | Methods and apparatus for communication with time-division duplexing |
US7584397B2 (en) | 2004-06-10 | 2009-09-01 | Interdigital Technology Corporation | Method and apparatus for dynamically adjusting data transmission parameters and controlling H-ARQ processes |
ATE363189T1 (en) * | 2004-09-13 | 2007-06-15 | Alcatel Lucent | ESTIMATION OF TRANSMISSION QUALITY IN A RADIO NETWORK |
US7492722B2 (en) * | 2004-11-04 | 2009-02-17 | Interdigital Technology Corporation | Wireless communication method and apparatus for adaptively biasing channel quality indicators to maintain a desired block error rate |
US7242956B2 (en) * | 2004-12-20 | 2007-07-10 | Motorola, Inc. | Rapid channel quality based power control for high speed channels |
WO2006075208A1 (en) * | 2005-01-14 | 2006-07-20 | Nokia Siemens Networks Oy | Hsdpa parameters adjustment based on cqi age |
US7522555B2 (en) * | 2005-01-21 | 2009-04-21 | Intel Corporation | Techniques to manage channel prediction |
JP4645208B2 (en) * | 2005-02-02 | 2011-03-09 | 富士通株式会社 | Wireless communication device |
US8848574B2 (en) | 2005-03-15 | 2014-09-30 | Qualcomm Incorporated | Interference control in a wireless communication system |
US8942639B2 (en) | 2005-03-15 | 2015-01-27 | Qualcomm Incorporated | Interference control in a wireless communication system |
EP1863196B1 (en) * | 2005-03-17 | 2019-07-31 | Huawei Technologies Co., Ltd. | Adaptive modulation control system, and wireless communication apparatus |
JP4615353B2 (en) * | 2005-04-14 | 2011-01-19 | 三菱電機株式会社 | Base station equipment |
US7711033B2 (en) | 2005-04-14 | 2010-05-04 | Telefonaktiebolaget Lm Ericsson (Publ) | SIR prediction method and apparatus |
US8965440B2 (en) | 2005-05-31 | 2015-02-24 | Alcatel Lucent | Method of estimating a current channel condition in a wireless communications network |
US9184898B2 (en) * | 2005-08-01 | 2015-11-10 | Google Technology Holdings LLC | Channel quality indicator for time, frequency and spatial channel in terrestrial radio access network |
BRPI0614259A2 (en) * | 2005-08-03 | 2012-01-24 | Matsushita Electric Ind Co Ltd | base station apparatus, communication terminal apparatus, and multiple carrier communication method |
EP1911186A2 (en) * | 2005-08-04 | 2008-04-16 | Thomson Licensing | Feedback control for adaptive video delivery |
JP4951274B2 (en) * | 2005-08-19 | 2012-06-13 | 韓國電子通信研究院 | CHANNEL INFORMATION GENERATION APPARATUS AND METHOD, AND APPLICABLE TRANSMISSION APPARATUS AND METHOD THEREOF |
KR101239600B1 (en) * | 2005-08-19 | 2013-03-05 | 파나소닉 주식회사 | Mobile station apparatus, base station apparatus and method for reporting cqi |
EP1760925A3 (en) * | 2005-09-05 | 2008-05-28 | Nokia Siemens Networks Gmbh & Co. Kg | Method and system for providing feedback information in a radio communication system |
JP4485438B2 (en) * | 2005-09-08 | 2010-06-23 | シャープ株式会社 | Portable terminal device, reception quality notification method, broadcast base station device, reception quality notification program, and recording medium |
KR20080068890A (en) | 2005-10-27 | 2008-07-24 | 콸콤 인코포레이티드 | Method and apparatus for estimating reverse link loading in a wireless communication system |
US8396041B2 (en) | 2005-11-08 | 2013-03-12 | Microsoft Corporation | Adapting a communication network to varying conditions |
WO2007057857A1 (en) * | 2005-11-16 | 2007-05-24 | Koninklijke Philips Electronics, N.V. | Adaptive, distributed solution for enhanced co-existence and qos for multimedia traffic over rlans |
US8381047B2 (en) * | 2005-11-30 | 2013-02-19 | Microsoft Corporation | Predicting degradation of a communication channel below a threshold based on data transmission errors |
US20070214379A1 (en) * | 2006-03-03 | 2007-09-13 | Qualcomm Incorporated | Transmission control for wireless communication networks |
US10686553B2 (en) * | 2006-03-20 | 2020-06-16 | Koninklijke Philips N.V. | Signal quality reporting |
TWI446744B (en) | 2006-03-20 | 2014-07-21 | Koninkl Philips Electronics Nv | Time varying signal quality reporting |
JP5065609B2 (en) | 2006-03-20 | 2012-11-07 | 株式会社エヌ・ティ・ティ・ドコモ | Base station, mobile station, and transmission path measurement signal transmission control method |
JP5024288B2 (en) * | 2006-04-27 | 2012-09-12 | 日本電気株式会社 | Mobile communication apparatus and reception quality information creation method |
US7778599B2 (en) * | 2006-05-01 | 2010-08-17 | Intel Corporation | Aggregated channel feedback |
US7894820B2 (en) | 2006-05-01 | 2011-02-22 | Intel Corporation | Channel feedback using channel state predictions based also on delays |
CN101432996A (en) * | 2006-05-01 | 2009-05-13 | 英特尔公司 | Channel feedback using channel state predictions based also on delays |
US7979075B2 (en) * | 2006-05-03 | 2011-07-12 | Telefonaktiebolaget Lm Ericsson (Publ) | Generation, deployment and use of tailored channel quality indicator tables |
TW200805925A (en) * | 2006-05-12 | 2008-01-16 | Interdigital Tech Corp | Method and system for signaling performance requirements of a wireless transmit/receive unit |
US7773951B2 (en) * | 2006-05-23 | 2010-08-10 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for generating channel quality information for wireless communication |
WO2007134406A1 (en) * | 2006-05-24 | 2007-11-29 | Cohda Wireless Pty Ltd | Method and apparatus for multicarrier communications |
WO2007140337A2 (en) * | 2006-05-25 | 2007-12-06 | Proximetry, Inc. | Systems and methods for wireless resource management |
US8559999B2 (en) * | 2006-05-29 | 2013-10-15 | Telefonaktiebolaget Lm Ericsson (Publ) | Channel quality prediction in HSDPA systems |
JP4998680B2 (en) * | 2006-06-19 | 2012-08-15 | 日本電気株式会社 | Pilot resource allocation method, channel quality measurement method and base station in mobile communication system |
JP4734186B2 (en) * | 2006-06-30 | 2011-07-27 | 富士通株式会社 | Mobile terminal device, reception control method in the same device, and wireless transmission system |
US8472448B2 (en) * | 2006-07-21 | 2013-06-25 | Intel Corporation | Wireless adaptive packet control message apparatus, systems, and methods |
WO2008025366A1 (en) * | 2006-08-29 | 2008-03-06 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and arrangement for link adaption signalling in a wireless communication network |
KR100957429B1 (en) * | 2006-08-31 | 2010-05-11 | 삼성전자주식회사 | Method and system for selecting relay station in a communication system |
US8442572B2 (en) * | 2006-09-08 | 2013-05-14 | Qualcomm Incorporated | Method and apparatus for adjustments for delta-based power control in wireless communication systems |
US20080117849A1 (en) * | 2006-09-08 | 2008-05-22 | Qualcomm Incorporated | Method and apparatus for interaction of fast other sector interference (osi) with slow osi |
JP4905007B2 (en) * | 2006-09-12 | 2012-03-28 | 富士通株式会社 | Uplink communication method and radio terminal in radio communication system |
US8688049B2 (en) | 2006-10-05 | 2014-04-01 | Telefonaktiebolaget L M Ericsson (Publ) | Method for predicting channel quality indicator (CQI) values |
CN101193312B (en) * | 2006-11-22 | 2011-01-05 | 中兴通讯股份有限公司 | Self-adapted error recovery device, video communication system and method based on feedback |
US7720136B2 (en) * | 2006-12-26 | 2010-05-18 | Provigent Ltd | Adaptive coding and modulation based on link performance prediction |
US8144667B2 (en) * | 2006-12-27 | 2012-03-27 | Alcatel Lucent | Methods for channel quality prediction error calculation and transmission power adjustment in a wireless network |
US9807803B2 (en) | 2007-03-01 | 2017-10-31 | Qualcomm Incorporated | Transmission control for wireless communication networks |
US7899015B2 (en) | 2007-03-02 | 2011-03-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for resource reuse in a communication system |
US20080220786A1 (en) * | 2007-03-05 | 2008-09-11 | General Instrument Corporation | Methods and Apparatus for Adaptively Selecting a Channel |
JP5206921B2 (en) * | 2007-03-16 | 2013-06-12 | 日本電気株式会社 | Resource allocation control method and apparatus in mobile radio system |
CN101111083B (en) * | 2007-08-13 | 2011-11-30 | 中兴通讯股份有限公司 | Quality feedback method for signal channel |
US8005131B2 (en) * | 2007-09-21 | 2011-08-23 | Intel Corporation | Delay compensation for transmit/receive chain calibration and multiuser MIMO |
CN101409576A (en) | 2007-10-12 | 2009-04-15 | Nxp股份有限公司 | Pre-encoding method and system for managing multiuser radio communication system |
JP5330406B2 (en) * | 2007-12-18 | 2013-10-30 | テレフオンアクチーボラゲット エル エム エリクソン(パブル) | Method and arrangement for facilitating radio resource allocation |
US8144797B2 (en) | 2008-03-25 | 2012-03-27 | Intel Mobile Communications GmbH | CQI table for wireless MIMO networks |
WO2009123515A1 (en) * | 2008-04-04 | 2009-10-08 | Telefonaktiebolaget L M Ericsson (Publ) | Interference reduction in a communication network by scheduling and link adaptation |
US8233427B2 (en) * | 2008-06-23 | 2012-07-31 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for generating channel quality estimates |
GB2461516A (en) * | 2008-06-30 | 2010-01-06 | Toshiba Res Europ Ltd | A method of predicting traffic in a wireless network |
KR100981885B1 (en) | 2008-07-08 | 2010-09-14 | 주식회사 이노와이어리스 | Mobile communication system of signal analysis method |
EP2312887B1 (en) | 2008-08-05 | 2019-01-23 | NEC Corporation | Path control system, path control device and path control method |
KR101294570B1 (en) * | 2008-08-08 | 2013-08-07 | 후지쯔 가부시끼가이샤 | Communication device, recording medium, and transmission data generation method |
AU2014201624B2 (en) * | 2008-08-08 | 2015-09-10 | Fujitsu Limited | Communication apparatus, transmission data generation program, and transmission data generation method |
GB2464973A (en) * | 2008-10-31 | 2010-05-05 | Toshiba Res Europ Ltd | A method of managing a transmission mode of a wireless device |
JP5103357B2 (en) * | 2008-11-04 | 2012-12-19 | 株式会社エヌ・ティ・ティ・ドコモ | Mobile terminal apparatus and radio base station apparatus |
CN101754385B (en) * | 2008-12-01 | 2014-01-29 | 日电(中国)有限公司 | Proportional fair dispatcher using failure CQI feedback and dispatching method |
CN101753187B (en) * | 2008-12-18 | 2013-08-07 | 电信科学技术研究院 | CQI estimation method, system and device during multi-stream beamforming transmission |
US8619563B2 (en) * | 2009-02-03 | 2013-12-31 | Qualcomm Incorporated | Method and apparatus for interference management in a wireless communication system |
CN102308633B (en) | 2009-02-09 | 2016-02-17 | 日本电气株式会社 | Contouring system, path control device, communication equipment, controlling of path thereof and program |
US8649456B2 (en) | 2009-03-12 | 2014-02-11 | Futurewei Technologies, Inc. | System and method for channel information feedback in a wireless communications system |
ES2637293T3 (en) | 2009-03-18 | 2017-10-11 | Electronics And Telecommunications Research Institute | Method for signaling CSI-RS subframe patterns |
JP4724761B2 (en) * | 2009-03-18 | 2011-07-13 | 株式会社エヌ・ティ・ティ ピー・シー コミュニケーションズ | Communication control device and program |
US8675627B2 (en) * | 2009-03-23 | 2014-03-18 | Futurewei Technologies, Inc. | Adaptive precoding codebooks for wireless communications |
KR100981886B1 (en) | 2009-04-21 | 2010-09-13 | 주식회사 이노와이어리스 | Mobile communication system of signal analysis method |
WO2011002356A1 (en) * | 2009-06-29 | 2011-01-06 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and arrangement in a wireless communication system |
US8369793B2 (en) | 2009-10-02 | 2013-02-05 | Telefonaktiebolaget L M Ericsson (Publ) | Channel-dependent scheduling and link adaptation |
US8395994B2 (en) * | 2009-10-28 | 2013-03-12 | Liveops, Inc. | System and method for adaptive call management |
US8743935B2 (en) | 2009-11-27 | 2014-06-03 | Nec Corporation | Wireless communication system, wireless communication apparatus and wireless communication method |
US9088999B2 (en) | 2010-01-27 | 2015-07-21 | Telefonaktiebolaget L M Ericsson (Publ) | Using information in multiple sub-bands to adaptively determine CQI |
EP2532108A4 (en) * | 2010-02-05 | 2017-11-01 | Telefonaktiebolaget LM Ericsson (publ) | Method and arrangement in a wireless communication system |
JP5405501B2 (en) * | 2010-02-25 | 2014-02-05 | パナソニック株式会社 | Communication apparatus and communication method |
US20110305209A1 (en) * | 2010-03-09 | 2011-12-15 | Qualcomm Incorporated | Rate adaptation for sdma |
EP2385643A1 (en) * | 2010-05-03 | 2011-11-09 | Alcatel Lucent | A method for selection of a modulation and coding scheme, and a device therefor |
CN102960028B (en) | 2010-06-17 | 2016-06-29 | 日本电气株式会社 | Path control device and controlling of path thereof |
EP2589173A1 (en) | 2010-07-01 | 2013-05-08 | Telefonaktiebolaget LM Ericsson (publ) | A method and an arrangement for determining a channel quality offset |
WO2012040935A1 (en) * | 2010-09-30 | 2012-04-05 | France Telecom Research & Development Beijing Company Limited | Channel quality information prediction method, device and system |
US8554151B2 (en) | 2010-12-03 | 2013-10-08 | Qualcomm Incorporated | Method and apparatus for data aided channel quality estimation |
US9225502B2 (en) * | 2011-03-31 | 2015-12-29 | Telefonaktiebolaget L M Ericsson (Publ) | Method and network node for determining channel state information in an upcoming time slot |
US8599711B2 (en) * | 2011-04-08 | 2013-12-03 | Nokia Siemens Networks Oy | Reference signal port discovery involving transmission points |
US20150245364A1 (en) * | 2012-02-16 | 2015-08-27 | Hewlett-Packard Development Company, L.P. | Radio resource management |
US9781643B2 (en) * | 2012-03-08 | 2017-10-03 | Blackberry Limited | Methods for improved inter-radio access technology measurements |
US9282473B2 (en) | 2012-06-07 | 2016-03-08 | Samsung Electronics Co., Ltd. | Wireless communication system with channel-quality indicator mechanism and method of operation thereof |
CN104662981A (en) * | 2012-07-02 | 2015-05-27 | 高通股份有限公司 | Building HS-SICHs in multi-carrier TD-HSDPA systems |
US8929239B2 (en) * | 2012-07-02 | 2015-01-06 | Apple Inc. | Modulation and coding scheme (MCS) recovery based on CQI offset |
US9167591B2 (en) * | 2012-09-06 | 2015-10-20 | Dell Products, Lp | Method and apparatus for determining optimized wireless link selection for a mobile device along a predicted path |
US9356681B2 (en) | 2013-05-10 | 2016-05-31 | Elwha Llc | Dynamic point to point mobile network including destination device aspects system and method |
US9380467B2 (en) | 2013-05-10 | 2016-06-28 | Elwha Llc | Dynamic point to point mobile network including intermediate device aspects system and method |
US9591692B2 (en) | 2013-05-10 | 2017-03-07 | Elwha Llc | Dynamic point to point mobile network including destination device aspects system and method |
US9832728B2 (en) | 2013-05-10 | 2017-11-28 | Elwha Llc | Dynamic point to point mobile network including origination user interface aspects system and method |
US9559766B2 (en) | 2013-05-10 | 2017-01-31 | Elwha Llc | Dynamic point to point mobile network including intermediate device aspects system and method |
US20140335907A1 (en) * | 2013-05-10 | 2014-11-13 | Elwha Llc | Dynamic Point to Point Mobile Network Including Base Station Aspects System and Method |
US9763166B2 (en) | 2013-05-10 | 2017-09-12 | Elwha Llc | Dynamic point to point mobile network including communication path monitoring and analysis aspects system and method |
US9474000B2 (en) | 2013-07-31 | 2016-10-18 | Qualcomm Incorporated | Handover and reselection searching using predictive mobility |
US20150038140A1 (en) * | 2013-07-31 | 2015-02-05 | Qualcomm Incorporated | Predictive mobility in cellular networks |
WO2015112173A1 (en) * | 2014-01-27 | 2015-07-30 | Hewlett-Packard Development Company, L.P. | Radio band assignment |
US9474064B2 (en) * | 2015-01-28 | 2016-10-18 | Alcatel Lucent | System and method for controlling an operation of an application by forecasting a smoothed transport block size |
US10307909B1 (en) | 2015-10-05 | 2019-06-04 | X Development Llc | Selectively uploading operational data generated by robot based on physical communication link attribute |
KR101856752B1 (en) * | 2016-08-03 | 2018-05-11 | 주식회사 케이티 | Method and apparatus for predicting signal quality in wireless network |
CN114097276A (en) * | 2019-07-19 | 2022-02-25 | Oppo广东移动通信有限公司 | Measurement reporting method, network equipment and terminal equipment |
WO2023219375A1 (en) * | 2022-05-09 | 2023-11-16 | Lg Electronics Inc. | Method and apparatus for measurement prediction in a wireless communication system |
KR20230165511A (en) | 2022-05-27 | 2023-12-05 | 부경대학교 산학협력단 | RC IGBT having a structure to suppress snapback |
Family Cites Families (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US131938A (en) * | 1872-10-08 | Improvement in saw-sets | ||
US665271A (en) * | 1900-02-26 | 1901-01-01 | Rogers Barr J | Piston-packing. |
US4335361A (en) * | 1977-09-01 | 1982-06-15 | Honeywell Inc. | Variable gain amplifier |
US4355361A (en) * | 1980-02-06 | 1982-10-19 | Sangamo Weston, Inc. | Data processor apparatus for multitariff meter |
US5305468A (en) * | 1992-03-18 | 1994-04-19 | Motorola, Inc. | Power control method for use in a communication system |
AU5550694A (en) * | 1992-11-06 | 1994-06-08 | Pericle Communications Company | Adaptive data rate modem |
US5722070A (en) * | 1995-04-12 | 1998-02-24 | Uniden America Corporation | Cell of preference check in a communications network |
JP2785804B2 (en) * | 1996-05-30 | 1998-08-13 | 日本電気株式会社 | Mobile communication system |
US5940439A (en) | 1997-02-26 | 1999-08-17 | Motorola Inc. | Method and apparatus for adaptive rate communication system |
US6108374A (en) * | 1997-08-25 | 2000-08-22 | Lucent Technologies, Inc. | System and method for measuring channel quality information |
US5953669A (en) * | 1997-12-11 | 1999-09-14 | Motorola, Inc. | Method and apparatus for predicting signal characteristics in a wireless communication system |
US6665271B1 (en) * | 1998-03-17 | 2003-12-16 | Transnexus, Llc | System for real-time prediction of quality for internet-based multimedia communications |
JP3437445B2 (en) * | 1998-05-22 | 2003-08-18 | 松下電器産業株式会社 | Receiving apparatus and method using linear signal prediction |
JP3485248B2 (en) | 1998-12-01 | 2004-01-13 | 松下電器産業株式会社 | Power line communication device |
JP2000315975A (en) | 1999-04-28 | 2000-11-14 | Hitachi Ltd | Mobile station unit |
DE69910449T2 (en) * | 1999-06-29 | 2004-06-24 | Nokia Corp. | METHOD AND DEVICE FOR POWER CONTROL |
US6621804B1 (en) * | 1999-10-07 | 2003-09-16 | Qualcomm Incorporated | Method and apparatus for predicting favored supplemental channel transmission slots using transmission power measurements of a fundamental channel |
DE19951797C2 (en) | 1999-10-27 | 2002-04-18 | Siemens Ag | Procedure for the dynamic allocation of resources in a digital radio communication system |
US6662310B2 (en) * | 1999-11-10 | 2003-12-09 | Symantec Corporation | Methods for automatically locating url-containing or other data-containing windows in frozen browser or other application program, saving contents, and relaunching application program with link to saved data |
US6731990B1 (en) * | 2000-01-27 | 2004-05-04 | Nortel Networks Limited | Predicting values of a series of data |
JP3704022B2 (en) * | 2000-04-25 | 2005-10-05 | 株式会社東芝 | Radio communication system, radio control station, and radio communication method |
AU2001267891A1 (en) | 2000-07-03 | 2002-01-14 | Matsushita Electric Industrial Co., Ltd. | Base station unit and method for radio communication |
JP2002050996A (en) | 2000-07-31 | 2002-02-15 | Sony Corp | Communication system transmitting signals coded using block lengths comprising with integral multiple interrelation via communication transmission path |
JP3741944B2 (en) * | 2000-09-18 | 2006-02-01 | 株式会社エヌ・ティ・ティ・ドコモ | Cell search method for mobile station in mobile communication system |
KR100355271B1 (en) * | 2000-10-11 | 2002-10-11 | 한국전자통신연구원 | Rain attenuation compensation method and system using adaptive transmission technique |
JP4403347B2 (en) | 2000-11-16 | 2010-01-27 | ソニー株式会社 | Information processing apparatus, information processing method, recording medium, communication system, and communication method |
US20020097686A1 (en) * | 2000-11-20 | 2002-07-25 | Qiu Robert C. | Long-range prediction of fading signals for WCDMA high speed downlink packet access (HSDPA) |
US6789065B2 (en) * | 2001-01-24 | 2004-09-07 | Bevocal, Inc | System, method and computer program product for point-to-point voice-enabled driving directions |
US7174178B2 (en) | 2001-07-19 | 2007-02-06 | Intel Corporation | Deriving a more accurate estimate from prediction data in closed loop transmit diversity modes |
KR100849333B1 (en) | 2001-10-12 | 2008-07-29 | 삼성전자주식회사 | Apparatus and method of channel estimator |
US6873852B2 (en) * | 2002-01-10 | 2005-03-29 | Telefonaktiebolaget Lm Ericsson (Publ) | System and method of estimating the position of a mobile terminal in a radio telecommunications network |
US20030142647A1 (en) * | 2002-01-31 | 2003-07-31 | Prathima Agrawal | Discrete soft handoff in CDMA wireless networks |
US7424270B2 (en) * | 2002-09-25 | 2008-09-09 | Qualcomm Incorporated | Feedback decoding techniques in a wireless communications system |
-
2003
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US7912490B2 (en) | 2011-03-22 |
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AU2003287399A8 (en) | 2004-06-07 |
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