KR101208513B1 - Method for Transmitting Channel Quality Information - Google Patents

Abstract

In the present invention, a channel quality information (CQI) transmission method applied to a system for transmitting data using two or more carriers, the entire frequency band is composed of a plurality of CQI bands, corresponding to the CQI band Transmitting CQI, but transmitting first information having a predetermined size or more by using medium access control (MAC) signaling and transmitting CQI corresponding to the CQI band, and transmitting second information having a predetermined size or less. The present invention relates to a method for transmitting channel quality information, comprising transmitting using a physical channel. The physical layer resource can be efficiently used, and the scheduling gain of the base station can be improved by transmitting accurate channel quality information. .

Channel quality information, scheduling, physical channel, MAC signaling

Description

Method for Transmitting Channel Quality Information

1 is a diagram illustrating an embodiment of a method for measuring and transmitting channel quality information in a mobile communication system.

2 is a diagram illustrating an embodiment of a method of transmitting a CQI using a physical layer channel.

3 is a diagram illustrating a method of transmitting a CQI using a physical layer channel and MAC signaling.

FIG. 4 is a diagram illustrating a method of transmitting DM information through a physical channel and transmitting CQI of the entire CQI band through MAC signaling among the embodiments according to FIG. 3.

The present invention relates to a method for reporting channel quality information, and more particularly, in a system for transmitting a signal using a plurality of frequencies, measuring a signal transmitted from a base station and transmitting the measured signal quality information to the base station. It is about how to.

1 is a diagram illustrating an embodiment of a method for measuring and transmitting Channel Quality Information (CQI) in a mobile communication system. Referring to FIG. 1, a user equipment (UE) 12 measures a channel quality transmitted through a downlink channel using a signal transmitted from a base station 11 (101). Then, the measured value is reported to the base station 11 (102). In this case, the measured channel quality may be transmitted using, for example, quantized CQI information, or may be transmitted as a carrier to interference and noise ratio (hereinafter, referred to as 'CINR'). The base station 11 performs scheduling such as mobile station selection, radio resource allocation, etc. using the received CQI.

Orthogonal Frequency Division Multiplexing (OFDM) divides a data stream having a high rate into a plurality of data streams having a low rate. In this case, a data stream is transmitted using a plurality of carriers corresponding to each divided data string. That is, each carrier is called a subcarrier, and since each carrier has orthogonality with each other, the receiver can independently detect a data stream transmitted through each carrier.

In a system that performs communication using a plurality of frequencies, such as OFDM, if only one CQI corresponding to the entire band is reported, channels of some frequency bands (frequency bands separated for CQI acquisition) constituting the entire band are reported. Quality status cannot be estimated accurately. Therefore, since it is impossible to perform scheduling using CQI for each frequency band constituting the entire band, there is a problem in that communication cannot be efficiently performed.

An object of the present invention is to efficiently utilize limited physical channel resources and to report more accurate CQI information so that efficient downlink scheduling is performed.

In order to achieve the above object, the present invention provides a channel quality information (CQI) transmission method applied to a system for transmitting data using two or more carriers, wherein the entire frequency band is composed of a plurality of CQI bands. Transmitting a CQI corresponding to the CQI band, transmitting first information having a predetermined size or more by using medium access control (MAC) signaling, and transmitting a CQI corresponding to the CQI band, And transmitting second information having a predetermined size or less using a physical channel.

The above-mentioned objects, features and advantages will become more apparent from the following detailed description in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As in the prior art, when all available bands are used as CQI measurement bands and an average CQI value is reported, scheduling of each detailed frequency band cannot be performed. On the other hand, the CQI reporting method using a physical channel is designed in such a way that frequency domain scheduling is not possible. In addition, it is difficult to transmit a large amount of control information because physical channel resources are limited. On the other hand, if the CQI is transmitted using MAC signaling, close operation with the physical channel is not easy, and time delay occurs, and thus it is difficult to adaptively cope with the channel change in the frequency domain.

Accordingly, the present invention provides a method of transmitting a small amount of information that requires fast delivery on a physical channel (CQICH) and a large amount of CQI information that is less sensitive to time than physical channel information on a MAC signaling. to provide.

You can use the following methods to report CQI. The CQICH channel method for reporting a CQI (eg, effective CINR) using a physical channel may be used, and the CQI (eg, effective CINR) may be reported using MAC signaling.

In order to measure downlink channel quality, the base station first informs the mobile station of the downlink quality measurement region (time and / or frequency domain). The measurement area means a pilot inserted in the data area, a preamble area transmitted to all mobile stations, or a resource area used for other purposes. The mobile station sends the CINR measurements for the designated area to the base station.

Meanwhile, in order to obtain gain by performing frequency domain scheduling, a band AMC operation mode may be defined. Band AMC operation mode divides the entire band into several AMC bands, and selects a mobile station and allocates resources based on the radio channel state of each band. In this case, the radio channel state information may be obtained from the CQI transmitted from the mobile station. For example, the mobile station may measure radio channel quality for a plurality of AMC bands, and report the ID (ID) and CINR values of some of the best AMC bands to the base station. The CQI reporting method is called a MAC signaling method.

2 is a diagram illustrating an embodiment of a method of transmitting a CQI using a physical layer channel. Hereinafter, a method of transmitting CQI information through the CQICH as an example of a physical layer channel will be described. As shown in Fig. 2, first, the base station transmits information about a measurement object to the mobile station (S21). That is, the information about the measurement target is a position in the time and / or frequency domain, and if the predetermined or the measurement region is not defined in advance, the base station is a reference to perform the downlink measurement (reference) signal to the mobile station to be measured. The measurement region refers to a time-frequency region composed of resource blocks (RBs) for pilot transmission.

In order to measure downlink quality, a pilot (for example, a preamble, a reference pilot, a reference signal) to which all mobile stations are commonly transmitted is specified without specifying a specific measurement region or a specific measurement region as described above. It can also be used to measure the channel.

In the case of using multiple antennas, an additional (for MIMO) pilot signal (or reference signal) may be additionally configured in addition to the common pilot, and a method of informing the mobile station may be selected. In the case of using multiple antennas, channel conditions are different for each antenna, and therefore, a dedicated pilot is required because channel estimation is required for each antenna. In this case, a base station needs to designate a mobile station to determine which pilot at which location. In this case, a method of designating a predetermined location and transmitting a location information and a corresponding pilot whenever necessary may be applied.

The base station allocates a physical layer control channel for CQI reporting to the mobile station (S22), and the mobile station obtains CQI information by measuring a signal transmitted through the measurement target region (S23). The mobile station transmits the obtained CQI information through the assigned physical layer control channel (S24).

Hereinafter, embodiments of a method of transmitting a CQI to a base station through a physical layer control channel will be described.

As a first embodiment, one average value for the entire CQI band may be transmitted to the physical layer. In this case, an identifier (ID) for each CQI band is unnecessary. In addition, a method of reporting the CQI value of the entire CQI band aperiodically may be added. However, when the amount of CQI information increases significantly, it is difficult to actively cope with this since the resources of the physical channel are limited.

As a second embodiment, differential information (DM) between a mean value and a previous mean value for the entire CQI band is transmitted. In this case, in order to cope with an error condition of the DM information, it is necessary to transmit average value information of the entire CQI band or non-average whole information periodically or aperiodically.

As a third embodiment, all of the individual values of the entire CQI band can be transmitted. In this case, while channel information is securely transmitted, the amount of physical channel control information to be transmitted can be greatly increased.

As a fourth embodiment, the CQI values of several (N) CQI bands of good (or good and bad) channel conditions are transmitted to the physical channel. In this case, ID information of the selected CQI band should be delivered.

As a fifth embodiment, the DM information of the CQI value of several (N) CQI bands with good (or good and bad) channel conditions can be transmitted. Even in this case, ID information of the selected CQI band should be transmitted. At this time, it is necessary to transmit the individual CQI value of the CQI band periodically or aperiodically.

As a sixth embodiment, only CQI values corresponding to one CQI band are transmitted at a time. In this case, a time delay may be long for transmitting all channel information of the entire CQI band. At this time, the selection of the CQI band is sequentially performed, and it may be necessary to transmit entire channel information periodically or aperiodically.

As a seventh embodiment, it is the same as the sixth embodiment, but only DM information is transmitted. In this case, it is sometimes necessary to transmit the entire channel information.

As an eighth embodiment, only one CQI band value is transmitted at a time. In this case, as an example of the selection criteria of the CQI band, it may be determined that the channel quality is the best or the worst case.

As a ninth embodiment, it is the same as the fourth embodiment but can transmit the selected N average CQI values.

When the CQI is transmitted to the base station in the same manner as in the above embodiment, the base station performs downlink scheduling using the received CQI (S25).

3 is a diagram illustrating an embodiment of a method of transmitting a CQI using a physical layer channel and MAC signaling. Hereinafter, a method of transmitting CQI information through the CQICH as an example of a physical layer channel will be described. As shown in Fig. 3, first, the base station transmits information on the measurement object to the mobile station (S31). That is, the information about the measurement target is a position in the time and / or frequency domain, and if the predetermined or the measurement region is not predefined, the base station transmits a pilot to perform downlink measurement. Inform the mobile station of the area to be measured. The measurement region refers to a time-frequency region composed of resource blocks (RBs) for pilot transmission.

In order to measure downlink quality, a specific measurement region or a specific measurement region is not specified as described above, and a channel using a pilot (for example, a preamble and a reference pilot) to which all mobile stations are commonly transmitted is used. It can also be measured.

In the case of using multiple antennas, an additional pilot signal (for MIMO) may be additionally configured in addition to the common pilot and the mobile station may be informed of this. In the case of using multiple antennas, channel conditions are different for each antenna, and therefore, a dedicated pilot is required because channel estimation is required for each antenna. In this case, a base station needs to designate a mobile station to determine which pilot at which location. In this case, a method of designating a predetermined location and a method of transmitting location information and a corresponding pilot whenever necessary are possible.

The base station allocates a physical layer control channel for CQI reporting and, if it is necessary to transmit MAC signaling information, also allocates MAC resources to the mobile station (S32). The mobile station obtains CQI information by measuring a signal transmitted through the measurement target region (S33). The mobile station transmits the acquired CQI information through the allocated physical layer control channel and / or MAC signaling (S34). If the uplink MAC resource is scheduled by checking the uplink MAC scheduling result, the physical control channel is determined. The channel quality information is transmitted using the MAC signaling. Meanwhile, if uplink MAC resources are not scheduled, channel quality information is transmitted using only the physical control channel.

Embodiments of a method of transmitting a CQI to a base station through a physical layer control channel and MAC signaling will be described below.

In a first embodiment, CQI values of N CQI bands selected as physical channels are transmitted. At this time, an example of the selection criteria is the channel quality state. Here, ID information of the selected CQI band is transmitted through a physical channel. Meanwhile, the CQI value of the entire CQI band may be transmitted through MAC signaling.

The second embodiment is similar to the first embodiment, but transmits a CQI value corresponding to some CQI bands whose values transmitted by MAC signaling are not all.

As a third embodiment, DM information of CQI values corresponding to N CQI bands selected as physical channels is transmitted. At this time, the ID information of the selected CQI band is transmitted to the physical channel. The CQI value of the entire CQI band is transmitted using aperiodic MAC signaling.

The fourth embodiment is the same as the third embodiment, except that the value transmitted through MAC signaling is DM information of the CQI value of a part of the selected CQI band instead of the whole.

As a fifth embodiment, CQI values of N CQI bands selected as physical channels are transmitted. At this time, the ID of the selected CQI band is transmitted by MAC signaling rather than a physical channel. Therefore, the ID information and the physical channel information must be kept synchronized during demodulation. In addition, it is necessary to transmit all the CQI values of the entire CQI band aperiodically.

As a sixth embodiment, DM information of CQI values of N CQI bands selected as physical channels is transmitted. At this time, the ID information of the selected CQI band is transmitted by MAC signaling. In addition, aperiodic CQI values for the entire CQI band are transmitted through MAC signaling.

The physical channel of the seventh embodiment is similar to the sixth embodiment. However, the CQI band ID selected by MAC signaling and the CQI value of the selected CQI band are transmitted. However, there is a problem in that the 'selected CQI band values' transmitted through the selected CQI band and the MAC signaling in the physical channel are not maintained in synchronization.

As an eighth embodiment, the CQI value of the entire CQI band is transmitted in both physical channel and MAC signaling. However, the physical channel is periodic information and the MAC signaling is transmitted aperiodically.

In a ninth embodiment, DM information of CQI values of all CQI bands is transmitted through a physical channel. In MAC signaling, the CQI value of the entire CQI band is transmitted aperiodically.

As a tenth embodiment, a CQI value for one CQI band is transmitted to a physical channel at a time, and then CQI values of the next CQI band are sequentially transmitted. The CQI value for the entire CQI band is transmitted aperiodically or periodically by MAC signaling.

The eleventh embodiment is similar to the tenth embodiment, but the CQI value transmitted on the physical channel is DM information.

In the twelfth embodiment, only one CQI band having a good quality is selected and transmitted to a physical channel at a time. At this time, the ID of the selected CQI band is transmitted to the physical channel. The CQI value for the entire CQI band is transmitted aperiodically or periodically with MAC signaling.

The thirteenth embodiment is similar to the twelfth embodiment except that the selected CQI band ID information is transmitted through MAC signaling. At this time, synchronization with the physical channel information should be maintained.

The fourteenth embodiment is similar to the first embodiment except that the average value of the selected CQI band is transmitted.

The fifteenth embodiment is similar to the fifth embodiment except that the average value of the selected CQI band is transmitted.

When the CQI is transmitted to the base station in the same manner as in the embodiment, the base station performs downlink scheduling using the received CQI (35).

4 is a diagram illustrating an embodiment of a method of transmitting DM information through a physical channel and transmitting CQI of the entire CQI band through MAC signaling among the embodiments according to FIG. 3. As shown in FIG. 4, the mobile station may transmit full CQI information (full CQI) corresponding to all CQI bands to the base station using MAC signaling. Meanwhile, the reference CQI value for CQI increase / decrease information according to DM may be transmitted using the MAC signaling. The mobile station may transmit CQI increase / decrease information (DM CQI) through a physical channel (eg, CQICH) based on the reference CQI value.

In this case, the information transmitted by the mobile station using MAC signaling may be transmitted by the base station at a time determined by the scheduler, or may be transmitted periodically or only when a specific event occurs. Meanwhile, the DM information is periodically transmitted through a physical channel. The DM information may be transmitted using one subframe. At this time, the transmission period of the DM information can be adjusted.

As described above, CQI requiring periodic and fast response may be transmitted to the physical layer, and information having aperiodic and large information amount may be transmitted using MAC signaling. In addition, DM can be used to minimize the amount of physical layer information. By transmitting in this way, it is possible to transmit accurate channel quality information that can respond quickly to channel changes, and minimize the amount of information transmitted to the physical layer.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention can effectively use the physical layer resources, it is possible to improve the scheduling gain of the base station by the accurate channel quality information delivery.

Claims (10)

In a system for transmitting data using a plurality of carriers, the mobile station transmits channel quality information (CQI) to a base station. Transmitting a first CQI corresponding to all CQI bands constituting the entire frequency band and having a size greater than or equal to a predetermined size by using medium access control (MAC) signaling; And Transmitting a second CQI corresponding to N CQI bands selected from all the CQI bands constituting the entire frequency band (where N is a positive integer) and having a size smaller than or equal to the predetermined size using a physical control channel; Including, How to send channel quality information The method of claim 1, The first CQI includes the CQI values of all the CQI bands constituting the entire frequency band. The method of claim 2, Wherein the second CQI includes differential modulation (DM) information of CQI values corresponding to the N CQI bands. The method of claim 3, wherein And the CQI value information for the differential modulation is transmitted through the MAC signaling. The method of claim 1, And transmitting the second CQI through the physical control channel periodically. 6. The method of claim 5, And a transmission period of the second CQI is an adjustable period. The method of claim 1, And transmitting the first CQI through the MAC signaling periodically. The method of claim 1, Transmission of the first CQI through the MAC signaling is controlled by the scheduler of the base station channel quality information transmission method The method of claim 1, The transmission of the first CQI through the MAC signaling is performed when a specific event occurs. The method of claim 1, Wherein the first CQI and the second CQI are information used for downlink scheduling.

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