KR20150130209A - SCHEME FOR detecting indicator information IN wireless communication system - Google Patents

Abstract

A method of detecting indicator information received by a receiver of a wireless communication system is provided, and the method includes determining a threshold value that reduces costs incurred by a false alarm rate that decides discontinuous transmission (DTX) information transmitted from a transmitter as non-DTX information and a missed detection rate that decides non-DTX information transmitted from the transmitter as DTX information; and detecting the indicator information using the threshold value. The threshold value is determined based on a reception quality level for acknowledgement (ACK) information when the transmitter transmits the ACK information.

Description

[0002] In wireless communication systems,

The present disclosure relates to a method of detecting indicator information transmitted in an indicator channel in a wireless communication system, and more particularly, to a method and apparatus for setting a threshold value and detecting indicator information using a set threshold value.

In the case of wireless communication, there are various kinds of indicator channels. For example, in response to a random access (RA) procedure of a receiver (e.g., a terminal), a transmitter (e.g., a base station) transmits an acquisition indicator (AICH) ). An acquisition indicator that is a response to a random access preamble may include, for example, ACK (acknowledge), NACK (negative acknowledge), and NoResponse (: no response).

The receiver receiving the indicator information from the transmitter compares the received value with a threshold value, and performs an operation of determining what the indicator information is, that is, a detection operation. These thresholds can be set to various criteria.

For example, a CFAR (constant false alarm rate detector) uses a certain false alarm probability threshold (CFAR threshold) for detection to satisfy a false alarm probability of a certain criterion.

As another example, a constant missed detection rate detector (CMDR detector) may be configured to satisfy a certain missed detection rate (MDR) by using a constant loss probability threshold (CMDR threshold) for detection .

As another example, there is a detection method that sets a threshold value at the same time considering both the probability of false alarm and the probability of loss. At this time, if there is no threshold value that simultaneously satisfies a certain criterion of the false alarm probability and the loss probability, an exceptional process (for example, a threshold value that satisfies any one of the false alarm probability and the loss probability may be selected) .

FIGS. 1 to 3 illustrate methods for setting a threshold for detecting indicator information using a PDF (probability density function) graph. FIG.

Figure 1 illustrates a detector 1 (i.e., a CFAR detector) that meets a certain false alarm probability and its threshold setting.

Figure 1 (a) illustrates a binary hypothesis H ₀ probability density of the received signal when the function (PDF) graph 100 and a binary hypothesis H ₁ day time when the overlap (overlapped) PDF graph 110 of the received signal. The probability of false alarm is the probability that the indicator information is determined as ACK when the indicator information is discontinuous transmission (DTX), and the probability of loss is the probability to be determined as DTX when the indicator information is ACK. At this time, the region showing the false alarm probability is the region 106 enclosed by the PDF graph 100 and the horizontal axis 190 when H ₀ in the right-hand plane of the vertical axis indicated by the threshold value eta (: eta) . ≪ / RTI > The area representing the loss probability can also be expressed as the area 104 surrounded by the PDF graph 110 and the horizontal axis 190 when H ₁ in the left plane of the vertical axis indicated by the threshold value eta 102 have.

FIG. 1B illustrates a case where the PDF graph 120 of the received signal does not overlap with the PDF graph 130 of the received signal when H ₁ is H ₀ . At this time, the area indicating the false alarm probability can be expressed as the area 124 surrounded by the PDF graph 120 and the horizontal axis 190 when H ₀ in the right-hand plane of the vertical axis indicated by the threshold value? have. However, the area enclosed by the PDF graph 130 when H ₁ is the vertical axis indicated by the threshold value? 122 is substantially zero. That is, when the PDF graph 120 at H ₀ and the PDF graph 130 at H ₁ do not overlap, there may be no region indicating the loss probability. That is, when the PDF graph 120 when the actual ACK information is transmitted and the PDF graph 130 of the received information when the DTX information is transmitted are not well-separated, A false alarm probability detector is not operating in spite of the fact that the threshold (CFAR threshold) can be set (larger) to further reduce the false alarm probability without increasing the missed detection rate (MDR). That is, the detector of FIG. 1 (b) is not operating the threshold adaptively.

2 illustrates a detector 2 (i.e., a CMDR detector) that satisfies a constant loss probability and its threshold setting.

2 (a) illustrates a case where the PDF graph 200 of the received signal overlaps the PDF graph 210 of the received signal when H ₁ is H ₀ . At this time, the area indicating the false alarm probability can be represented by the area 206 surrounded by the PDF graph 200 and the horizontal axis 290 when H ₀ in the right-hand plane of the vertical axis indicated by the threshold value eta 202 have. The area representing the loss probability can also be expressed as the area 204 surrounded by the PDF graph 210 and the horizontal axis 290 when H ₁ in the left plane of the vertical axis indicated by the threshold value 202 have.

2B illustrates a case where the PDF graph 220 of the received signal does not overlap with the PDF graph 230 of the received signal when H ₁ is H ₀ . At this time, the area indicating the loss probability can be expressed as a region 224 surrounded by the PDF graph 230 and the horizontal axis 290 when H ₁ in the left-hand side of the vertical axis indicated by the threshold value? have. However, the area enclosed by the PDF graph 220 when H ₀ and the vertical axis indicated by the threshold value? 222 is substantially zero. That is, in the case where the PDF graph 220 at H ₀ and the PDF graph 230 at H ₁ do not overlap, there may be no region indicating a false alarm probability. That is, in the case where the PDF 220 when the actual ACK information is transmitted and the PDF 230 of the reception information when the DTX information is transmitted are not overlapped but are not overlapped, the constant loss probability detector can detect the loss Though you can set the threshold (the CMDR threshold) to be smaller (even smaller) to further reduce the probability, you are not operating this way. That is, the detector 2 of FIG. 2 (b) also does not operate the threshold value adaptively. However, the detector of FIG. 2 estimates the SNR _ACK (Signal to Noise Ratio for ACK) when the indicator information is actually transmitted as _ACK through the supplementary information of the higher layer or blind estimation blind estimation.

FIG. 3 illustrates a detector 3 that satisfies a certain false alarm probability and a constant loss probability and threshold setting thereof.

3 (a) illustrates a case in which a certain false alarm probability and a constant loss probability are satisfied at the same time. For example, in FIG. 3A, the threshold value? 302 is a value corresponding to 1/2 of the average value? (Corresponding to the gain of the ACK signal) of the PDF graph 310 of the received signal when H ₁ Respectively.

Figure 3 (b) illustrates the setting of the detector threshold η (= μ / 2) (322) that minimizes the simple arithmetic sum of two probabilities (exceptionally) when both the probability of a false alarm and the probability of a constant loss are not satisfied at the same time . As another example, the threshold may be set to satisfy only one of the two criteria of false alarm probability and loss probability.

The threshold value satisfying only one criterion is set as the threshold value satisfying the criteria of the false alarm probability and the loss probability respectively, And the method of applying the threshold value of the detector to minimize the sum of the loss probability does not determine the optimal threshold value. Therefore, an improved technique for determining the threshold value of the detector is required.

The threshold value determination techniques of the detector described in FIGS. 1 to 3 determine thresholds to be applied to the indicator information determination by independently considering or simultaneously considering the false alarm probability and the loss probability. The decision techniques simply assume that the costs incurred by the false alarm event and the loss event are the same and that only the minimization of the false alarm probability and the loss probability or the minimization of the simple sum of the false alarm probability and the loss probability are considered, And has lost the opportunity to optimize performance. That is, in the detectors described in FIGS. 1 to 3, no consideration is given to the actual costs incurred due to the false alarm probability and the loss probability. However, for example, in the case of AICH of wideband code division multiple access (WCDMA), costs such as call setup delay may be significantly different from each other for false alarms and losses. Accordingly, the present disclosure provides a technique for determining a threshold value in consideration of a false cost and a real cost based on a loss probability.

Unlike the traffic information of the data channel for minimizing the symbol error probability, the indicator channel indicator information has a substantial cost due to the false alarm or loss event, Costs need to be considered. Accordingly, the present disclosure provides a threshold determination method for minimizing the overall cost by reflecting different actual costs to the cost function modeling for each of the false alarm probability and the loss probability, and a detection method and apparatus using the same.

The present invention relates to a method of detecting indicator information received at a receiver of a wireless communication system, the method comprising the steps of: determining a discontinuous transmission (DTX) information transmitted from a transmitter as non-DTX information; Determining a threshold value that minimizes a cost caused by a loss probability to be determined as DTX information; And detecting the indicator information using the threshold value, wherein the threshold value is determined based on a reception quality ratio for the ACK information when the transmitter transmits ACK (acknowledge) information. Method.

The present invention also relates to a receiver apparatus for detecting indicator information received in a wireless communication system, the receiver apparatus comprising: a false alarm probability for determining DTX (discontinuous transmission) information transmitted from a transmitter as non-DTX information; To the DTX information; a control unit for determining a threshold value that minimizes the cost caused by the loss probability of determining the DTX information; And a detector for detecting the indicator information using the threshold value, wherein the threshold is determined based on a reception quality ratio for the ACK information when the transmitter transmits ACK information. Device.

Detectors of this disclosure can use thresholds to reduce the probability of false alarms without increasing the loss probability.

Also, the detector of the present disclosure can use a threshold for detection to reduce the probability of loss without increasing the probability of false alarm.

By applying a threshold that minimizes the cost that a receiver pays for the inventive detector, the receiver (or terminal) of the present disclosure minimizes cost, such as call-out latency, and thus can improve the competitiveness of the user experience quality.

1 is a diagram illustrating a CFAR detector satisfying a certain false alarm probability and its threshold setting;
FIG. 2 is a diagram illustrating a CMDR detector and its threshold setting satisfying a constant loss probability; FIG.
3 is a diagram illustrating a detector that satisfies a combination of a certain false alarm probability and a constant loss probability and threshold setting thereof;
4 illustrates a configuration of a wireless communication receiver device for detecting indicator information in accordance with the present disclosure;
5 is a diagram illustrating a detection method using the reception quality factor threshold value for detection according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure the subject matter of the present disclosure. The terms used herein are defined in consideration of the functions of the present disclosure, which may vary depending on the user, the intention or custom of the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Prior to the detailed description of the present disclosure, an example of an interpretable meaning is provided for some terms used herein. However, it should be noted that the present invention is not limited to the interpretation given below.

In the present disclosure, the transmitter may be a base station of a wireless communication system. A base station is a base for communicating with a terminal, and may be referred to as a BS, a NodeB (NB), an eNode B (eNB), an AP (Access Point), or the like.

In this disclosure, a receiver may be a terminal of a wireless communication system. A user equipment may be referred to as a UE, a mobile station (MS), a mobile equipment (ME), a device, a terminal, or the like as a subject communicating with a base station.

In the present disclosure, a detector means a module provided in a receiver and determining a value of received information using a threshold value. The detector may be referred to as a detector to indicate that it is a configuration module of the receiver.

For convenience of explanation, it is assumed in this disclosure that the indicator information transmitted by the transmitter is binary, i.e., two non-DTX (e.g., ACK) and DTX. However, the content of the present disclosure is not limited to the case where the indicator information to be transmitted is non-binary (e.g., ACK, NACK), such as, for example, a 3GPP Enhanced-Dedicated Channel (E-HICH) , DTX, and so on).

The proposed scheme of the present disclosure will be described by applying to a method of detecting indicator information (ACK / NACK / DTX) of an AICH (Acquisition Indicator Channel) of a 3GPP (3 ^rd generation partnership project) WCDMA. However, the technique of the present disclosure is applicable not only to 3GPP WCDMA AICH, but also to all wireless communication receivers that apply a detection method that compares received values with threshold values to determine what information is received. Therefore, the present invention is applicable to all receivers that detect and compare indicator information of an indicator channel with a threshold value. For example, the detection scheme of the present disclosure can be applied to a paging indicator channel (PICH), a multimedia broadcast and multicast service (MBMS) indicator channel of a WCDMA system, an E-HICH, and an E-DCH relative grant channel The present invention is also applicable to a receiver of a secondary synchronization channel (S-SCH) that receives space time transmit diversity (STTD) encoding information. Also, the detection technique of the present disclosure can be applied to a detection method of an ACK / NACK information receiver of an uplink HS-DPCCH (high speed downlink packet access) system of HSDPA, (physical hybrid-ARQ indicator channel) receiver of a long term evolution system (PHICH).

4 is a diagram illustrating a configuration of a wireless communication receiver device for detecting indicator information in accordance with the present disclosure;

The receiver according to the present disclosure may include at least one of a radio frequency (RF) signal processing unit 400, a baseband signal processing unit 405, a detection unit 410, and a control unit 415.

The RF signal processor 400 receives a radio wave and converts the received radio wave into a digital signal.

The baseband signal processing unit 405 obtains an indicator signal by removing the influence of the channel from the received digital signal using a specific signal processing algorithm. The baseband signal processing unit 405 measures the reception quality ratio SNR _y of the indicator information from the indicator signal and delivers the reception quality ratio SNR _y to the detector 410. The baseband signal processor 405 may be implemented as a module, for example, a rake receiver.

The detector 410 determines indicator information using an indicator signal from which the influence of the channel is removed. Specifically, the detector 410 may determine the indicator information by comparing the received indicator signal y with the threshold value?, Or by comparing the reception quality ratio SNR _y with the reception quality ratio threshold value SNR _th .

The control unit 415 determines a reception quality ratio threshold value (? Or SNR _th ) that minimizes the total cost by using an expectation value for the cost of the false alarm event and an expected value for the cost of the loss event, And transmits the threshold value to the detector 410.

The RF signal processing unit 400, the baseband signal processing unit 405, the detection unit 410, and the control unit 415 included in the receiver of this disclosure are shown as separate components, The components may be implemented as one module, such as the controller 415. Alternatively, all operations of the detection method described in this disclosure can be understood to be performed by the control unit 415. [

Before describing a method of setting the reception quality ratio threshold value SNR _th proposed in the present disclosure, a system model of a received signal will be described.

It is assumed that the received signal y of the indicator information is modeled as follows.

Here, a is indicator information, mu (mu) is a gain term, and w is Additive White Gaussian noise (AWGN) with an average of 0 and a noise power of ² . a can be classified as follows.

H _n represents a hypothesis. When H ₀ , a = 0, which indicates that the indicator information is DTX. The DTX is indicator information processed by the receiver to 0 when the transmitter did not send the indicator information. When H ₁ , a = -1, which indicates that the indicator information is NACK. When H ₂ , a = + 1, which indicates that the indicator information is ACK.

For convenience of explanation, in the present disclosure, the kind of the indicator information is simplified by binary (i.e., on-off keying) as follows. However, it should be noted that the example of the present disclosure does not limit the extension to the case of detecting non-binary indicator information. For example, the detection technique of the present disclosure can also be used to detect ternary indicator information (i.e., ACK / NACK / DTX).

That is, the case where the indicator information is DTX and ACK will be described as an example. When H ₀ , a = 0, which indicates that the indicator information is DTX. When H ₁ , a = + 1, which indicates that the indicator information is ACK.

W in Equation (1) can be modeled as follows.

N is a noise function with mean (0) and noise power as a factor. Here, it is assumed that the receiver that receives the indicator information estimates and knows the noise power ( ² ).

When the transmitter transmits an ACK as indicator information, the reception quality ratio SNR _ACK of the indicator information at the receiver is defined as follows.

The receiver knows whether the power (sigma ² ) of the ACK signal, which is a numerical term of the reception quality ratio information, is directly received from a higher layer or is transmitted to the receiver, or a sequence of information already determined to be non-DTX And is assumed to be known. For example, in a 3GPP frequency division duplex (FDD) system, a receiver uses an AICH power offset indicative of a gain term ( ² ) to calculate an ACK from a SNR estimate of a primary common pilot channel (P-CPICH) The power of the signal can be indirectly calculated. Alternatively, in the case of an indicator channel (e.g., 3GPP E-HICH) whose power offset relative to the P-CPICH is unknown, the receiver estimates the power offset of the E-HICH versus the P- -HICH < / RTI >

It is assumed that the received signal y has the following probability distribution (PDF) f for the case of each of the binary hypotheses (i.e., H ₁ and H ₀ ).

For example, the method of a certain false alarm probability detector (CFAR detector), which can be applied to a Neyman-Pearson detector, is described.

A likelihood ratio test of Equation 8 or a log-likelihood ratio test of Equation 9 is performed to maximize the detection probability P _D under a constraint satisfying the target false alarm probability P _FA . Can be performed.

’는 정의상(by definition) 등가임을 의미하고, γ (: gamma)는 우도비 검정에 이용되는 임계 값이다. 즉, 우도비 검정은 인디케이터 정보가 0 인 경우의 확률분포에 대한 인디케이터 정보가 1인 경우의 확률분포의 비율을 임계 값 γ와 비교하는 검정이다.here, '

'Means by definition equivalence, and γ (: gamma) is the threshold used for likelihood ratio test. That is, the likelihood ratio test is a test for comparing the ratio of the probability distribution when the indicator information for the probability distribution is 1 when the indicator information is 0, to the threshold value gamma.

=H₁)할 확률 즉, 검파 확률 P_D는 다음과 같이 정의된다.If the receiver determines ACK (H ₁ ) as ACK (

= H ₁ ), that is, the detection probability P _D is defined as follows.

=H₁)할 확률 즉, 오경보 확률 P_FA는 다음과 같이 정의되며, 우도비 검정의 임계 값 γ는 P_FA 정의로부터 설정될 수 있다.Where P is a probability function. The receiver determines the transmitted DTX (H ₀ ) as ACK (

= H ₁ ), that is, the false alarm probability P _FA is defined as follows, and the threshold value γ of the likelihood ratio test is P _FA Can be set from the definition.

By using Equations (6) and (7), the log likelihood ratio test of Equation (9) can be modified as follows.

Here, the reception signal observation value y can be used as a test statistic by defining the threshold value eta (: eta) as follows.

The receiver can calculate the false alarm probability P _FA by comparing the received signal observation value y with the threshold value? As shown in Equation (14).

The receiver can calculate the detection probability P _D as shown in Equation (15) by comparing the received signal observation value y with the threshold value?.

Equation (14) and Equation (15) can be summarized by using Equation (5), it can be easily seen that the detection probability P _D and the false alarm probability P _FA have a mathematical relationship such as Equation (16) or Equation (17).

Here, the definitions of the Q function and the erf function (: error function) are as shown in Equations (18) and (19), respectively, and are already known in the technical field.

Next, a method of setting the reception quality ratio threshold value (? Or SNR _th ) proposed in the present disclosure in the system model of the reception signal as described above will be described.

Applying the Q ^-1 function (inverse of the Q function) and the erf ^-1 function (inverse of the erf function) to the result of equation (14), the threshold value η can be described as P _FA as follows.

The reception quality ratio of the reception indicator signal is SNR _y = y ² /? ² , and the threshold value of the reception quality ratio used for indicator information determination is SNR _th =? ² /? ² . Therefore, the operation of comparing the signal observation value y with the threshold value? Can in fact be considered to be the same as the operation of comparing y ² /? ² with? ² /? ² . Thus, the operation of comparing y to eta can be considered to be the same as the operation of comparing SNR _y with SNR _th .

The threshold values of the detectors described in FIGS. 1 to 3 will be described in terms of the above Equation 16 and Equation 17 as follows.

Detector 1 of Figure 1 (b) sets the P _FA satisfying the threshold value η to achieve, as a target value a certain false alarm probability detector. However, the detector 1 of FIG. 1 (b) does not use the SNR _ACK information, thereby losing the chance of improving the performance of reducing the false alarm probability P _FA without decreasing the detection probability P _D. That is, the detector 1 of FIG. 1 (b) does not consider the case where the two probability distributions of the received signal y for each case of the binary hypothesis are separated without overlapping.

Detector 2 in FIG. 2 (b) is a detection method for achieving a target detection rate or a desired detection rate, and uses a SNR _ACK information to set a threshold value? That satisfies a target detection rate. Although the detector 2 of FIG. 2 (b) also uses the SNR _ACK information, only the target detection probability P _D is taken into consideration, thereby losing an opportunity to improve the detection probability P _D without increasing the false alarm probability P _FA . That is, the detector 2 of FIG. 2 (b) does not consider the case where the two probability distributions of the received signal y for the respective cases of the binary hypotheses are separated without overlapping.

The detector 3 of FIG. 3 (a) uses such a threshold value when the threshold value eta simultaneously satisfying both the target detection probability P _D and the target false alarm probability P _FA is present at the same time, or when there is no such threshold value, Detector 3 of b) selects one performance indicator to prioritize the false alarm probability or target detection probability according to various policies or minimizes the simple sum of false alarm probability and detection probability (that is, 1: 1 weight value) But does not take into account the overall cost of the receiver system.

That is, the detectors 1, 2, and 3 in FIGS. 1 to 3 merely satisfy the target false alarm probability or detection probability at the same time or consume a simple sum, and do not consider the system overall cost.

By treating the indicator information differently from the symbol error rate of other information (e.g., traffic information over a common data channel), the receiver of the present disclosure is able to determine whether the detector is in an erroneous determination of indicator information Consider the cost of That is, the present disclosure proposes a detection technique and a detection device for setting an optimal threshold value? In consideration of the cost of erroneous determination. Alternatively, the receiver of the present disclosure may determine a reception quality ratio threshold SNR _th =? ² /? ² that is in an equivalent relationship to the threshold value?.

The present disclosure describes a method for setting an optimal threshold by considering a call setup delay experienced by a user as a cost in a receiver of a WCDMA FDD system in detecting an AICH as an example. Since the method described below is merely an example, there is no restriction on the extension and application of the contents of this disclosure to other possible environments. That is, the SNR _ACK at the time of receiving the actual ACK is estimated using the information of the upper layer or the SNR _ACK can be indirectly estimated from the past sequence information of the indicator information which has already been received and determined as the ACK information The contents of this disclosure can be applied.

The cost function using the call origination delay time experienced by the receiver user can be modeled as follows.

Here, C _xy is the cost of determining the hypothesis H _x as the hypothesis H _y .

If the cost is applied to the call origination delay time, Equation (22) can be expressed as follows.

Here, T _xy Is the temporal cost when the hypothesis H _x is determined as the hypothesis H _y . In the present disclosure, since time is regarded as a cost, C _xy is _expressed as T _xy .

T ₀₀ is a call reception delay time when DTX is determined by DTX, that is, when a correct reject occurs. It is assumed in the present disclosure that T ₀₀ is equal to T ₁₀ .

T ₀₁ is a call reception / reception delay time when a DTX is judged as a non-DTX (for example, ACK), that is, a false alarm, and can be regarded as approximately one second, for example.

T ₁₀ may have various values according to the conditions given to the receiver according to the WCDMA FDD standard with respect to non-DTX (e.g., ACK) DTX, i.e., call origination delay time in case of missed detection For example, it can be regarded as 16 ms.

T ₁₁ is a call reception / reception delay time when non-DTX (for example, ACK) is determined as non-DTX (for example, ACK), that is, when detection occurs. By assuming that there is no hit in case of call subalsin delay, T ₁₁ may be regarded as 0ms.

Although it is an exemplary value, it can be seen that the cost of T ₀₁ is not equal to T ₁₀ but has a value of several times.

=H₀)하는 손실(missing) 확률 P_M과 ACK으로 결정(

=H₁)하는 적중 확률 P_D의 합은 1이므로, 손실 확률 P_M 는 1- P_D과 같다. 또한, 수신기가 송신된 DTX (H₀)을 DTX로 결정(

=H₀)하는 정기각 확률과 ACK으로 결정(

=H₁)하는 오경보 확률 P_FA의 합은 1이므로, 정기각 확률 P(

=H₀|H₀)은 1 - P_FA와 같다. 수학적 처리(mathematical manipulation)을 거쳐 상기 수학식 23의 비용 C를 간략화 하면 수학식 24와 같다.The receiver determines the transmitted ACK (H ₁ ) as DTX (

= H ₀ ) is determined by the probability of missing P _M and ACK (

Since H = ₁₎ to the sum of the hit probability P _D is 1, the loss probability P _M are as 1- P _D. Also, determine the DTX (H ₀₎ of the receiver is sent to the DTX (

= H ₀ ) and the ACK (

= H ₁ ), the sum of the false alarm probability P _FA is 1, so that the periodic angle probability P (

= H ₀ | H ₀ ) is equal to 1 - P _FA . Simplifying the cost C of equation (23) through mathematical manipulation is shown in equation (24).

Also, for the mathematical formality during the derivation process of Equation 24, the following is assumed.

It is assumed that the cost function C of Equation 24 always has a minimum value for? ² /? ² . Therefore, (the threshold value SNR _th = η ² / σ ² on or _{^{SNR y = y 2 / σ 2}} ) Equation optimum threshold ask the solution of partial differential equations 26 η for the cost function C of equation (24) is Can be determined.

The optimal threshold value SNR _th (i.e., SNR _{th _ MinCost} ) can be summarized as follows by solving the differential equation of Equation (26) through some mathematical manipulation.

The conditions of the equations (28) and (29) are assumed on the derivation process of Equation (27).

P (H ₀ ) = P (H ₁ ) = 1/2, assuming that H _o and H ₁ are equi-probable events because there is no A-priori probability for the binary hypothesis. 2, Equation 29 for the optimal threshold value SNR _th can be further simplified as follows.

As described in Equation 30, the threshold SNR _th that minimizes the cost according to the present disclosure includes the reception quality factor SNR _ACK of the indicator received signal upon receipt of the actual ACK as a factor. The cost minimization threshold also includes consideration of the actual costs T ₀₁ and T ₁₀ that the receiver (or user) pays for each of the false alarm probability and loss probability. Thus, the detectors of the present disclosure have better performance than conventional detectors. Explanation of the concrete improvement effect on the cost as the performance index is omitted.

5 is a diagram illustrating a detection method using the reception quality factor threshold value for detection according to the present disclosure.

It should be noted that the receiver according to the present disclosure can implement the detection scheme of the present disclosure by performing only a part of the operations indicated in FIG. That is, it should be noted that not all of the procedures shown in FIG. 5 have to be performed to implement the technique of the present disclosure.

The receiver receives and processes the RF signal and receives the indicator signal from the RF signal. The receiver calculates 500 the reception quality ratio SNR _y from the received indicator signal each time it receives the indicator signal through the indicator channel.

The receiver computes the expected reception quality ratio SNR _ACK at the time of receiving the actual ACK information using the information of the upper layer or if it can not receive the help of the upper layer, it determines that it is not the received DTX (non-DTX) It can be indirectly estimated from the sequence value of the indicator reception information. Specifically, the receiver checks whether SNR _ACK calculation is possible using information of an upper layer (505). If the result of the check 505 is possible, the receiver may calculate an SNR _ACK using upper layer information (510). If the result of the check (505) is not possible, the receiver can indirectly estimate the SNR _ACK using the sequence number of the previously received non-DTX determined indicator received information (515).

The receiver may calculate the cost (C _xy ) as needed (520). Alternatively, the receiver may store and use a value calculated as a cost (C _xy ). For example, the cost C _XY may be the time that the receiver (or user) experiences and may be expressed as T _XY .

The receiver includes the C _xy And SNR _ACK A threshold (SNR _th or?) That minimizes the overall cost based on the information may be calculated (525). The threshold value SNR _th may be determined using Equation (30), for example. Alternatively, the receiver may store the pre-computed threshold value (e.g., look-up table or the like) without calculating the threshold value each time and set the stored threshold value to the threshold value to be used by the detection section of the receiver You can decide.

The receiver can determine (i.e., detect) whether the indicator information is DTX or ACK by comparing the reception quality ratio SNR _y of the received indicator information with the determined threshold value SNR _th or? ).

In the above description, the present invention has been mainly described with respect to the configuration for comparing the quality ratio SNR _y of the received signal with the threshold SNR _th for the reception quality ratio. However, the technique of the present disclosure may also be applied to a detector that compares the received information y with a threshold value [eta].

It should be noted that the configuration diagram of the receiver device illustrated in FIGS. 4 and 5 and the exemplary illustration of the detection method are not intended to limit the scope of the present disclosure. That is, not all of the components or operation steps described in FIGS. 4 to 5 should be construed as essential components for the practice of the present disclosure, and even if only a few components are included, Lt; / RTI >

The above-described operations can be realized by providing a memory device storing the program code in a receiver of the communication system or in any component in the terminal device. That is, the control unit of the receiver or terminal device can execute the above-described operations by reading and executing the program code stored in the memory device by a processor or a CPU (Central Processing Unit).

The various components, modules, and the like of the receiver or terminal device described herein may be implemented in hardware circuits, such as complementary metal oxide semiconductor (CMOS) based logic, firmware, May be implemented using hardware circuitry such as software and / or a combination of hardware and firmware and / or software embedded in a machine-readable medium. In one example, the various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and custom semiconductors.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present disclosure should not be limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims (22)

A method for detecting indicator information received at a receiver of a wireless communication system,
DTX information transmitted from the transmitter is determined as non-DTX information, and a threshold value that minimizes the cost caused by the loss probability of determining non-DTX information transmitted from the transmitter as DTX information is determined Operation; And
And detecting the indicator information using the threshold value,
Wherein the threshold is determined based on a reception quality ratio for the ACK information when the transmitter transmits ACK (acknowledge) information. The method according to claim 1,
The threshold value is a threshold value? For the received indicator information y,

≪ / RTI >
Here,? Is the signal power of the received indicator information, erf ^-1 is an inverse function of an error function, and P _FA is a false alarm probability. The method according to claim 1,
Wherein the cost comprises a call origination delay time caused by the false alarm probability and the loss probability. The method according to claim 1,
The threshold is characterized in that the threshold value SNR _th of the quality factor _y SNR (signal to noise ratio of y) of the received indicator information. 5. The method of claim 4,
And calculating the quality ratio SNR _y of the received indicator information,
Wherein the detecting the indicator information using the threshold value is an operation of comparing the quality ratio SNR _y of the received indicator information with the threshold value SNR _th to determine the indicator information. 6. The method of claim 5,
The threshold SNR _th that minimizes the cost

And

≪ RTI ID = 0.0 > and / or < / RTI >
Here, T ₀₁ is the case of No. subalsin delay false alarms, T ₁₀ is lost, and in case of call subalsin delay time, P (H ₀₎ is the probability the assumption that the said indicator information DTX, P (H ₁₎ is information the indicator Is a non-DTX probability, and SNR _ACK is a reception quality ratio for the ACK information. The method according to claim 1,
The operation of determining a threshold value that minimizes the cost caused by the false alarm probability and the loss probability,
Calculating a threshold that minimizes said cost; And
And selecting at least one threshold value in a table in which the threshold for minimizing the cost is stored. The method according to claim 1,
Wherein the reception quality ratio SNR _ACK for the ACK information is calculated from information of the upper layer received or calculated from a sequence of indicator information previously received and determined as non-DTX. 5. The method of claim 4,
Wherein the quality ratio SNR _y of the received indicator information is defined as y ² / σ ² or y ² . The method according to claim 1,
Wherein the indicator information is binary information, and the non-DTX information includes ACK information. The method according to claim 1,
Wherein the indicator information is non-binary information, and the non-DTX information includes ACK information and negative acknowledgment information. A receiver apparatus for detecting indicator information received in a wireless communication system,
DTX information transmitted from the transmitter is determined as non-DTX information, and a threshold value that minimizes the cost caused by the loss probability of determining non-DTX information transmitted from the transmitter as DTX information is determined ; And
And a detector for detecting the indicator information using the threshold value,
Wherein the threshold is determined based on a reception quality ratio for the ACK information when the transmitter transmits ACK (acknowledge) information. 13. The method of claim 12,
The threshold value is a threshold value? For the received indicator information y,

Gt; a < / RTI > device,
Here,? Is the signal power of the received indicator information, erf ^-1 is an inverse function of an error function, and P _FA is a false alarm probability. 13. The method of claim 12,
Wherein the cost includes a call origination delay time caused by the false alarm probability and the loss probability. 13. The method of claim 12,
The threshold value device is characterized in that the threshold value SNR _th of the quality factor _y SNR (signal to noise ratio of y) of the received indicator information. 16. The method of claim 15,
And a baseband signal processor for calculating a quality ratio SNR _y of the received indicator information,
Wherein the detector compares the quality ratio SNR _y of the indicator information with the threshold SNR _th to determine the indicator information. 17. The method of claim 16,
The control unit calculates the threshold SNR _th that minimizes the cost

And

Wherein the device is determined by any one of < RTI ID = 0.0 >
Here, T ₀₁ is the case of No. subalsin delay false alarms, T ₁₀ is lost, and in case of call subalsin delay time, P (H ₀₎ is the probability the assumption that the said indicator information DTX, P (H ₁₎ is information the indicator Is a non-DTX probability, and SNR _ACK is a reception quality ratio for the ACK information. 13. The method of claim 12,
Wherein the controller determines the threshold value by performing one of an operation of calculating a threshold value for minimizing the cost or an operation of selecting at least one threshold value in a table storing a threshold value for minimizing the cost, . 13. The method of claim 12,
The baseband signal processor calculates a reception quality ratio SNR _ACK for the ACK information using the information of the upper layer received or calculates a reception quality ratio SNRACK for the ACK information from a sequence of indicator information previously determined to be non- And calculates a reception quality ratio SNR _ACK . 16. The method of claim 15,
Wherein the quality ratio SNR _y of the received indicator information is defined as y ² /? ² or y ² . 13. The method of claim 12,
Wherein the indicator information is binary information, and the non-DTX information includes ACK information. 13. The method of claim 12,
Wherein the indicator information is non-binary information, and the non-DTX information includes ACK information and negative acknowledgment information.

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