KR100683340B1 - Reverse packet control channel processing method at base station - Google Patents

Abstract

 The present invention relates to a processing method of a reverse packet data control channel (R-PDCCH), in particular, received in a base station in a mobile communication system.

The reverse packet control channel processing method in the base station according to the present invention comprises the steps of: receiving and buffering the packet data frame transmitted from the terminal; Combining the correlation values of the currently received frame and the correlation values of the buffered previous frame to detect an index of a reverse packet data control channel with respect to the received current packet data frame; Detecting a maximum correlation value among the combined correlation values; Determining whether the maximum correlation value is greater than or equal to a predetermined threshold value, and determining an index having the correlation value as an R-PDCCH index if the maximum correlation value is greater than or equal to a threshold value.

1x EVDV, R-PDCH, R-PDCCH, SPID

Description

Processing method Reverse Packet Data Control CHannel in base station

1 is a block diagram illustrating a reverse packet control channel processing apparatus in a base station according to an exemplary embodiment of the present invention.

2 is a flowchart illustrating a reverse packet control channel processing method in a base station according to an exemplary embodiment of the present invention.

3 is a table showing a mapping table for the R-PDCCH index and information in the 1x EVDV system.

The present invention relates to a processing method of a reverse packet data control channel (R-PDCCH), in particular, received in a base station in a mobile communication system.

A typical mobile communication system, for example, a code division multiple access (CDMA) mobile communication system such as IS-2000, only supports voice and low speed circuit and packet data services. As communication technology develops along with user demands, mobile communication systems are developing in the form of supporting high-speed packet data services.

In particular, mobile communication systems such as the International Standard (IS) -2000 1x-EVDV (Evolution in Data and Voice) have received much attention in recent years as supporting high-speed packet data services as well as voice.

At the same time, the development of a mobile communication system capable of supporting both voice service and high speed packet data service in both the forward and reverse directions is being progressed. Among them, 1x-EVDV REV. In a system such as the D system, in order to improve packet data transmission efficiency, various information about a packet data channel (PDCH) is transmitted through a packet data control channel (PDCCH) in the same time interval. do.

The packet data control channel (PDCCH) and the packet data channel (PDCH) are transmitted in pairs at the same time. In particular, during a high speed packet data service, a method for quickly and accurately demodulating a reverse packet data control channel is required. It became.

Here, the control information transmitted on the forward packet data control channel includes a reception address, a transmission rate, a modulation scheme, and the like of the transmission data, which is used to receive the forward packet data channel.

The control information transmitted on the reverse packet data control channel (R-PDCCH) includes an encoder packet size (EP_SIZE), a subpacket ID (SPID), a boost indication, and an MSIB (mobile). Status Indicator Bit) and the like, which are used for reception of a reverse packet data channel (R-PDCH).

Here, the UE can know whether the reverse packet data channel (R-PDCH) frame transmitted to the base station through the forward acknowledgment channel (F-ACKCH) has been successfully received. That is, when a negative acknowledgment (NAK) is received through the F-ACKCH, the R-PDCH frame is retransmitted and a new packet is transmitted when the ACK (ACKnowledgement) is received.

In this case, when retransmitting the R-PDCH frame, the reverse packet data control channel (R-PDCCH) information has the same encoder packet size (EP_SIZE) and boost indication, and the subpacket identifier (SPID) is in the retransmission order of the packet. According to the different values, the retransmission period and the maximum number of transmissions are predetermined.

When the control information of the R-PDCCH is transmitted to the base station in this manner, the base station obtains only the maximum value of the correlation values obtained every frame from the result of the Hardmard transform, and when the detected maximum correlation value exceeds the threshold. The R-PDCCH index is determined directly from the index.

However, since the base station does not combine the control information of the R-PDCCH, the base station exhibits a high missing rate, and does not consider the TPR (TPR) and the SubPacket ID (SPID) of the R-PDCCH. As long as one threshold is used, the False Alarm Rate is high.

A first object of the present invention is to combine a predetermined number of reverse packet data control channel frames retransmitted for decoding of reverse packet data from a terminal.

A second object of the present invention is to receive a reverse packet data control frame identified by a subpacket identifier, buffer a predetermined number of cells, and combine them to obtain a reverse packet data control channel index.

A third object of the present invention is to obtain a maximum value of the combined correlation values from a certain frame, compare the threshold value, and determine an index corresponding to a correlation value that is greater than or equal to the threshold as the reverse packet data control channel index.

A fourth object of the present invention is to make it possible to apply fifteen grouped thresholds reflecting the subpacket identifier and traffic pilot ratio.

Reverse packet control channel processing method in the base station according to the present invention for achieving the above object,

In a system for receiving reverse high speed packet data (R-PDCH),

Receiving and buffering a frame of the packet data control channel transmitted from a terminal;

Combining the correlation values of the currently received frame and the correlation values of the buffered previous frame to detect an index of a reverse packet data control channel with respect to the received current packet data frame;

Detecting a maximum correlation value among the combined correlation values;

Determining whether the maximum correlation value is greater than or equal to a predetermined threshold value, and determining an index having the correlation value as an R-PDCCH index if the maximum correlation value is greater than or equal to a threshold value.

Preferably, the buffering step may include buffering up to a certain previous frame according to the retransmission period and the maximum number of retransmissions upon retransmission of reverse packet data.

Preferably, each buffered frame is buffered with 60 correlated absolute values obtained after Hadamard transform.

Preferably, the buffered frame is characterized in that up to eight buffered.

Preferably, the combine step is performed according to an index of a subpacket identifier (SPID = O, SPID = 1, SPID = 2) region.

Preferably, the threshold value is applied differently for each SPID index.

Preferably, the threshold of the combined correlation value is applied differently for each subpacket identifier and traffic pilot ratio (TPR).

Preferably, the threshold for the combined correlation value is applied to 60 indexes with 15 thresholds grouped by SPID and TRP.

In addition, the reverse packet data control channel processing method in the base station according to another embodiment of the present invention, in the system for receiving reverse high speed packet data (R-PDCH), receiving and buffering the frame of the reverse packet data control channel And determining an R-PDCCH index through a combination of an R-PDCCH frame for the received current frame and a correlation value for the buffered predetermined previous frames.

Specifically, the combine may be performed by combining the absolute value of the correlation value by using the correlation value of the current frame and the frames before 4 and 8 frames; And if the correlation value having the maximum value among the combined correlation values exceeds a threshold, determining the index having the correlation value as the R-PDCCH index.

Specifically, when the R-PDCCH index is determined, a subpacket identifier, encoder packet size, and boost indication for reverse packet data corresponding to the index may be obtained.

Specifically, when the maximum correlation value exceeding the threshold is determined, the value of MSIB is determined by the sign of the correlation value.

Referring to the accompanying drawings, a method for processing a reverse packet data control channel in a base station according to an embodiment of the present invention configured as described above is as follows.

First, the present invention is a schematic operation for transmitting the reverse packet data control channel (R-PDCCH) from the terminal to the base station is as follows. In the standard (e.g., 1x EVDV REV.D system), it is mapped to a 6-bit binary value according to encoder packet size (EP_SIZE), subpacket identifier (SPID), boost indication (BOOST_INDICATION), and then (6,64 After orthogonal modulation, sequence repetition and Walsh code are covered, followed by PN (pseudo noise) and complex multiplication as quadrature-phase data.

In contrast, the R-PDCCH receiver of the base station is configured as shown in FIG. This corresponds to the reverse process when the R-PDCCH is transmitted. In the receiving process, the frame received in the reverse process is despreaded by the PN (10), decovered with a Walsh code (20), and only quadrature data is selected (30). Since the quadrature phase selector 30 transmits the R-PDCCH data as the data on the quadrature, the receiver discards the in-phase data component and selects only the quadrature data.

Then perform a Sequence De-Repetition (40), perform a Hadamard Transform (50) to find the 6-bit binary value from the obtained 64 symbols and frame the result. Not much combine (60).

In the 1X EVDV REV.D system, the R-PDCCH includes an encoder packet size (EP_SIZE), a subpacket identifier (SPID), a boost indication (BOOST_INDICATION), and a mobile status indicator bit (MSIB). In order to decode, the encoder packet size and subpacket identifier for the PDCH must be obtained from the R-PDCCH. Here, the MSIB includes information on the power state and data amount of the terminal, and usually has a value of 0 or 1.

In addition, the UE can know whether the R-PDCH frame transmitted through the F-ACKCH was successfully received at the base station. If the base station is not successfully received, the terminal receives the NAK through the F-ACKCH, and successfully transmitted. If so, it will receive an ACK. At this time, the terminal retransmits the R-PDCH when receiving the NAK.

When the R-PDCH is retransmitted, the R-PDCCH information has the same EP_SIZE and BOOST_INDICATION, has a value of 0, 1, 2 according to the SPID order, and can be transmitted up to three times.

That is, one physical encoder packet may be transmitted up to three times. In this case, the encoder packet size and the boost indication of the R-PDCCH are maintained at the same value, and the sub packet identifier is different each time it is retransmitted. Value, with a maximum value of 2. If the SPID is transmitted first by a new packet, SPID 0 is transmitted. In the second transmission, SPID 1 is transmitted after 4 frames. In the third transmission, the SPID is sent again to SPID 2 after 4 frames.

Of these R-PDCCH information, EP_SIZE, SPID, and boost indications are represented by six bits in combination, and these six bits have an index of 0 to 59 and are orthogonally modulated with a Walsh code having a length of 64. The MSIB is then subjected to biorthogonal modulation.

The information of the R-PDCCH, the Walsh code mapped when the information is orthogonally modulated, and the TPR (Traffic Pilot Ratio) at that time are shown in Table 1 below.

Index SPID TPR (dB) 0,1 0 -5 2 ~ 4 0 -4 5 ~ 10,33 ~ 34 0 -3 35-37 0 -2 38-41 0 -One 11,12 One -5 13-15 One -4 16-21,42-43 One -3 44-46 One -2 47-50 One -One 22,23 2 -5 24 ~ 26 2 -4 27-32,51,52 2 -3 53-55 2 -2 56-59 2 -One

Here, the mapping table for the R-PDCCH index and the information is as shown in FIG. Referring to FIG. 3, the R-PDCCH index is 0 to 59. If the index is 0 to 10, the SPID 0 and the EP_SIZE are 0 to 10. If the index is 11 to 21, the SPID 1 and the EP_SIZE are 0 to 10 and the index 22 32 means SPID 2 and EP_SIZE 0-10. Again, SPID 0 and EP_SIZE are 0 to 8 for indexes 33 to 41, SPID 1 and EP_SIZE for 0 to 8 for indexes 42 to 50, and SPID 2 and EP_SIZE 0 to 8 for indexes 51 to 59. The boost indication has a false value (FALSE = 0) for indexes 0-32 and a true value (TRUE = 1) for indexes 32-59.

For example, when a new R-PDCH packet is sent, if the SPID is 0 of the R-PDCCH and the boost indication is 0, the R-PDCCH index is 0-10, and if the boost indication is 1, the PDCCH index is 33-41.

The R-PDCH control information as described above is obtained from a PDCCH index obtained by combining certain R-PDCCH frames.

For the R-PDCCH combine, as a result of the Hadamard transformation, 60 correlation values C _f (i) are buffered by taking absolute values for the previous eight frames. Accordingly, the R-PDCCH index is obtained by combining the R-PDCCH frames, and a threshold (T: Threshold) for detecting the R-PDCCH index is set differently for each TPR and SPID. That is, the frames that can be combined in any f-th frame are the f-4th frame and the f-8th frame.

The process of combining the above R-PDCCH for each frame is as follows.

If the 60 correlation values obtained after the Hadamard transform for the f th frame are C _f (i), the previous 4 th and 8 th frames (f-4, f-8) for combining of the R-PDCCH frames Absolute value of correlation for all | C _f-4 (i) |, | C _f-8 (i) | Will be buffered.

In this case, to obtain the R-PDCCH index for the f th frame, a combined correlation value C _{c, f} (i) is obtained by applying the following combine algorithm.

For the indexes i = 0 to 10 and i = 33 to 41 having SPID 0, a combine formula such as Equation 1 is applied.

Here, Equation 1 obtains the combined correlation values by taking the absolute values of the correlation values for the SPID 0 region for the current frame f, respectively.

For index i = 11 ~ 21 having SPID 1, a combine formula such as Equation 2 is applied.

For i = 42 ~ 50 of the SPID 1 indexes, a combine formula such as Equation 3 is applied.

Equations (2) and (3) indicate a correlation value [C _f (i)] for the SPID 1 region and a correlation value [C _f ) for the SPID 0 region for the previous f-4 frame in order to obtain a correlation value for the current frame f. _f-4 (i-9), C _f-4 (i-11)], divided by 1/2, and then summed to obtain the combined correlation values for SPID 0,1.

For i = 22 ~ 32 among the SPID 2 indexes, a combine formula such as Equation 4 is applied.

For i = 51 ~ 59 among the SPID 2 indices, a combine formula such as Equation 5 is applied.

Equations 4 and 5 denote correlation values [C _f (i)] for the SPID 1 region and correlation values for the SPID 0 region for the previous f-4 frame in order to obtain a correlation value for the current frame f. _f-4 (i-9), C _f-4 (i-11)], and the correlation values for the SPID 2 region for the previous f-8 frame [C _f-8 (i-22), C _f-8 (i-18)], each divided by 1/3, and then the combined correlation values for the SPID 0, 1, 2 areas are obtained, respectively.

As such, when SPID 0 is obtained using Equation 1, correlation values obtained by the current frame are obtained, respectively. When SPID 1 is used using Equations 2 and 3, SPID 0,1 corresponding to the f-4th frame is obtained. The combined correlation values are obtained, and when the SPID is 2, the combined correlation values of SPIDs 0, 1, and 2 corresponding to the f-8th frame are obtained.

The maximum value [C _max , _f ] and the index value [idxMax] of the correlation values C_c, f (i) for the indexes I = 0 to 59 thus obtained are obtained, respectively. This is shown in Equation 6.

At this time, the maximum correlation value C _{max, f} and the index having the same are obtained. The maximum correlation value is compared with the threshold value T (idxmax) set in the index, and when the correlation value is larger than the threshold value, the index at that time is determined as the R-PDCCH index. That is, if C _{max, f} > T (idxmax), the index (i = idxmax) becomes the R-PDCCH index. Here, the threshold may be a threshold having a predetermined value or may be a threshold determined for each SPID region. Alternatively, different thresholds may be set for each index of the SPID. Alternatively, as described below, the threshold values may be grouped according to a predetermined number of SPID indexes.

In this case, when the R-PDCCH index is determined, the MSIB becomes O if the sign of the correlation value [C _f (idxMax)] having the maximum value that is the result of the Hadamard transform is 0, and 1 if the sign is negative.

In this case, if the maximum correlation value is less than or equal to the threshold of the index, the R-PDCCH index is not obtained for the f-th frame, which is the current frame. can not do it.

On the other hand, the threshold [T (index)] applied above is a threshold that is applied differently for each index (i), it is applied as a threshold (spid, tpr) differently according to the SPID and TPR (Traffic Pilot Rlgain). The threshold for each index is shown in Table 2 below.

Table 2 shows 15 grouped thresholds applied to 60 indexes. This allows you to apply the thresholds for 60 indexes into 15 groupings, combining three SPIDs (SPIDs 0, 1, 2) and five TPRs (-5, -4, -3, -2, -1). do.

Index T (spid, tpr) 0,1 T (0, -5) 2 ~ 4 T (0, -4) 5 ~ 10,33 ~ 34 T (0, -3) 35-37 T (0, -2) 38-41 T (0, -1) 11,12 T (1, -5) 13-15 T (1, -4) 16-21,42-43 T (1, -3) 44-46 T (1, -2) 47-50 T (1, -1) 22,23 T (2, -5) 24 ~ 26 T (2, -4) 27-32,51,52 T (2, -3) 53-55 T (2, -2) 56-59 T (2, -1)

2 is a flowchart illustrating a reverse packet data control channel processing method according to an exemplary embodiment of the present invention.

Referring to FIG. 2, when a current frame is received (S11), the correlation absolute value of the received frame is obtained and buffered (S12). Here, the buffered frame is buffered up to eight frames (f-1, ..., f-8).

In this case, after combining the absolute absolute values of three frames f, f-4, and f-8 to obtain the R-PDCCH index (S13), the subpacket identifier (SPID 0, 1, 2) region is performed. Combined correlation values for are obtained, respectively (S14).

At this time, the maximum correlation value is obtained from the index of the subpacket identifier, that is, 60 indexes (i = 0 to 59), and is compared with a threshold value of the index corresponding to the obtained maximum correlation value (S15). At this time, if the maximum correlation value is larger than the threshold of the corresponding index, the index having the obtained correlation value is determined as R-PDCCH.

Accordingly, the encoder packet size, subpacket identifier, and boost indication corresponding to the R-PDCCH index are obtained, and the MSIB is obtained from the sign (+,-) of the maximum correlation value (S17). Through this, since the currently received R-PDCH can be decoded, the R-PDCCH frame detection for this packet is terminated (S18).

However, if the maximum correlation value is smaller than the threshold of the corresponding index, the R-PDCCH frame is error processed and the current R-PDCH frame cannot be decoded (S19).

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

As described above, according to the reverse packet data control channel processing method in the base station according to the present invention, when the current frame is received, the previous frames carrying the subpacket identifier can be combined together, thereby increasing the detection probability of the R-PDCCH and increasing the error. The probability is that it can be reduced.

In addition, by applying the threshold compared to the correlation value differently for the subpacket identifier (SPID) and the traffic pilot ratio (TPR) in order to detect the index of the R-PDCCH, the R-PDCCH The detection probability is increased and the error probability is reduced.                     

In addition, the present invention improves the detection probability of the R-PDCCH, thereby improving the reception performance of the R-PDCH frame, and has an effect of increasing the reverse throughput.

In addition, the present invention reduces the false alarm or error rate for the received frame, thereby preventing the unnecessary allocation of resources of the modem required for R-PDCH decoding, thereby increasing the efficiency of modem resource utilization.

Claims (15)

In a system for receiving reverse high speed packet data (R-PDCH), Receiving and buffering a frame of the reverse packet data control channel transmitted from a terminal; Combining the correlation values of the currently received frame and the correlation values of the buffered previous frame to detect an index of the received current packet data control channel; Detecting a maximum correlation value among the combined correlation values; Determining whether the maximum correlation value is greater than or equal to a predetermined threshold value, and determining an index having the correlation value as an R-PDCCH index if the maximum correlation value is greater than or equal to a threshold value. The method of claim 1, The buffering step of the reverse packet data control channel processing method characterized in that for re-transmission of the frame of the reverse packet data control channel, up to a predetermined number of previous frames according to the retransmission period and the maximum number of retransmissions. The method of claim 1, And wherein each buffered frame is buffered with 60 correlated absolute values obtained after Hadamard transform. The method of claim 1, And up to eight buffered frames. The method of claim 1, The combine step is performed according to a predefined formula according to the index of the subpacket identifier (SPID = O, SPID = 1, SPID = 2) region, characterized in that the reverse packet data control channel processing method. The method of claim 5, The combine for the subpacket identifier region 0 applies the following combine formula to the index (i = 0-10, i = 33-41) of the subpacket identifier 0 ,

Here, C _{c, f} (i) is a combined correlation value for the f th frame, and C _f (i) is a correlation value of the index of SPID 0 of the f th frame. Way. The method of claim 5, If the subpacket identifier region is 1, the following combine formula is applied to the index (i = 11 to 21) of the subpacket identifier 1.

If the subpacket identifier region is 1, the following combine formula is applied to the index (i = 42 to 50) having the subpacket identifier 1,

Here, C _{c, f} (i) is the combined correlation value for the f th frame, C _f (i) is the correlation value of the index of SPID 1 of the f th frame, C _f-4 is the f-4 th frame And a correlation value for an index of SPID 0 of the reverse packet data control channel. The method of claim 5, If the subpacket identifier region is 1, the following combine formula is applied to the index (i = 22 to 32) having the subpacket identifier 2.

If the subpacket identifier region is 1 , the following combine formula is applied to the index (i = 51 to 59) having the subpacket identifier 2 .

Here, C _{c, f} (i) is a combined correlation value for the f th frame, C _f (i) is a correlation value of the index of SPID 2 of the f th frame, and C _f-4 is the f-4 th frame And a correlation value for the index of SPID 1 of C _f-8 is a correlation value for the index of SPID 0 of the f-8th frame. The method of claim 1, And the threshold is applied differently for each SPID index. The method of claim 1, The threshold value of the combined correlation value is differently applied to each subpacket identifier and traffic pilot ratio (TPR). The method of claim 1, And a threshold for the combined correlation value is applied for 60 indexes with 15 thresholds grouped by SPID and TRP. delete delete delete delete

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