Method for batch data transmission in wireless communication system with harq with adaptive compensation of bias of quality assessment of channel

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to a method of data transmission in a wireless communication system with hybrid automatic request for repetition (HARQ). Assessment bias compensation CQI is performed by processing of HARQ receipts (7), a signal-code sequence (SCS) is chosen based on compensated assessment CQI, coding of a data batch (6) is performed by its help, after that, the first attempt of transmission of the batch of coded data to a receiver (4) is performed via a forward channel (2), the success of which is determined as per the type of HARQ receipt (7) received from the receiver (4) via a backward channel (3) in response to this attempt. In case the received HARQ receipt (7) is not positive, repeated attempt of batch transmission is performed via the forward channel (2). In order to provide the adaptive compensation of bias of assessment CQI, the first measure (S) is determined using at least two last HARQ receipts and based on it there determined is a value of a factor of coarse compensation, the second measure (T) is determined using at least one of the last HARQ receipts and based on it there determined is a value of a factor of fine compensation, a reset operation of the value of the fine compensation factor is performed till the initial value at the change of the current value of the coarse compensation factor and CQI assessment is changed considering values of the obtained values of the coarse compensation factor and the fine compensation factor.

EFFECT: providing control of the level of successful delivery of data from the first try of transmission; improving the efficient use of radio resources and speed of data transmission in a wireless communication system as a whole.

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AREA of TECHNOLOGY

The invention relates to the field of wireless communication, and more specifically to a method of packet data transmission in wireless communication systems with hybrid automatic repeated (HARQ), in particular in communication systems such as LTE or WiMAX.

The LEVEL of TECHNOLOGY

The known method of packet data with the offset compensation assessment (CQI) quality of the direct channel (Kari Aho, Olli Alanen, Jorma Kaikkonen "CQI Reporting Imperfections and their Consequences in LTE Networks", ICN 2011, The Tenth International Conference on Networks, St. Maarten, The Netherlands Antilles, 2011, pp. 241-245), in which compensation is performed by subtracting from the CQI estimation of a single factor compensation, the value of which is reduced by A fixed amount each time you receive on the backward channel positive HARQ receipt in response to the first attempt to transmit a packet or increase at a fixed value of B every time you get on the backward channel HARQ-receipt, non-positive, in response to the first transmission attempt of the packet. To ensure delivery on the first attempt transfer-level (1-PER) values of A and B communicate with each other and with the target probability PER (Packet Error Rate) unsuccessful delivery of the packet from the first attempt by the relation:

PER=1/(1+B/A).

The disadvantage of this technical solution is that when the characteristic values of the target probability of unsuccessful delivery�VCI PER (0,1) the value of the ratio B/A should be fairly large (at least 9). To ensure this is the value of the ratio B/A, step A compensation factor must be sufficiently small. However, for a small value of A is not secured by a quick transition to the steady-state mode of operation when there is a significant negative offset for CQI estimation. Moreover, due to possible variations of the offset of the CQI estimation in time in some cases is not guaranteed entry into stationary mode. To address this deficiency through this way you can offer or increase the step B of the compensation factor, or to limit the operating range of the values of the compensation factor. In the first case, this leads to less accurate offset estimation CQI, which is also a disadvantage, because, in turn, leads to decrease of efficiency of use of radio resources and the transmission speed due to less effective CCM. In the second case, the workspace of the method is limited to a narrow range of offsets assessment CQI, outside which the method does not provide control of packet delivery on the first attempt transmission at the target level (1-PER), which is also a disadvantage of this method.

The closest analogue of the present invention is a method of packet data in wireless communication system with hybrid automatic repeated (HARQ) and periodic accessed�m from the receiver on the reverse channel message, containing an assessment of the quality of the direct channel (see patent US 20110243208 A1 priority date 28.02.2010 G., published date 06.10.2011). This method consists in the fact that they exercised deferred compensation offset of CQI estimation by processing the HARQ-receipts, on the basis of the compensated evaluation select signal-code construction (CCM), perform the encoding of the data packet to produce a first attempt at transmission of the encoded data packet to the receiver via the direct channel, the success of which is judged by referring to HARQ-receipts received through the backward channel, followed by at least one retransmission of the transmission of the data packet if the received HARQ-receipt was not positive. In the known method, the offset compensation estimation CQI performed by subtracting from the value of CQI is the only factor compensation, calculated using its previous value and functions of corrections that depend on the current level of probability of failed transmission PER package or on a combination of PER and throughput. The function of the amendment has a three-form, namely, when the argument values above the first threshold, it takes a value such that the value of the compensation factor increases by a constant, at values of the argument below the second threshold, it accepts values such �the value of the compensation factor is reduced by another constant, and in other cases - the value of the compensation factor remains unchanged.

In the known technical solution, the use of metrics or PER combination PER bandwidth, does not allow to control the level of successful (or unsuccessful) delivery of packets from the first transmission attempt, which is essential for a number of wireless communication systems with hybrid automatic repeated HARQ, such as LTE, WiMAX, etc., because the success or failure of a packet on subsequent attempts is not exposed to significant information about how effectively was selected by the CCM for the first attempt of transmission, because for a variety of transmission attempts CCM can be used with different code speeds for which the probability of successful packet transmission is different.

In addition, the step functions of the amendment leads to a loss of precision offset to the CQI estimation and reduce the effectiveness of the use of the canal as a whole, especially when the value of the metric between the first and second threshold values.

The use of this technical solution is characterized by a slow transition in the steady-state mode of operation and poor adaptability to the working conditions that caused slow reaction to changes the offset of CQI estimation due to the fairly long period of accumulation of statistic to get the value �etrice with the required accuracy. The increase in absolute value functions of the amendment results in a proportional decrease in the accuracy of compensation of the offset of the CQI estimation, which in turn leads to decrease of efficiency of use of radio resources and the transmission speed due to less effective CCM.

Summary of the INVENTION

Task to be solved by the present invention is to provide a method of packet data in wireless communication system with hybrid automatic repeated (HARQ), for example, in the mobile communication system of the fourth generation (4G) LTE (Long Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access), which would offset compensation estimation CQI quality of the direct channel is carried out in a manner that ensures control of the level of successful delivery of data from the first transmission attempt, and this also increased the use efficiency of radio resources and data transmission speed in wireless communication system as a whole.

The problem is solved in that in the method of transmitting data in wireless communication system with hybrid automatic repeated (HARQ) and receiving from the receiver on the reverse channel message containing an assessment (CQI) quality of the direct channel, consisting in the fact that carry out offset compensation estimation CQI by processing the HARQ-receipts, on the basis of the UK�pensylvannia assessment CQI chosen signal-to-code design (CCM), carry out the encoding of a data packet, perform the first attempt to transmit a packet of encoded data to the receiver via the direct channel, the success of which is judged by referring to HARQ-receipts received from the receiver on the reverse channel in response to this attempt, after which if received previous HARQ-receipt was not positive, carry out at least one retransmission of the packet on a direct channel, according to the invention, compensation of the offset of the CQI estimation is performed by determining the first metric using at least the last two HARQ-receipts, determine the value of factor gross compensation taking into account the value of the first metric, determining a second metric using at least one of the last HARQ-receipts, determine the value of factor slim compensation taking into account the value of the second metric, the operation of resetting the value of the factor slim compensation to the initial value when changing the current values of the factor of gross compensation, changes in the CQI estimation with the values obtained values of gross factor compensation factor and fine compensation.

Preferably the first metric to be defined as the ratio of the number of successful first attempts to transmit packets to the total number of successful and unsuccessful first attempt to transfer paketo�.

Thus preferably the value S of the first metric to determine in accordance with the relationship:

,

where W is the number of HARQ-receipts received on the reverse channel from the receiver in response to the first attempts to transmit packets made since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time, a Swas positive HARQ-receipts from this number.

Possible value S of the first metric to determine periodically at equal intervals of time.

Preferably at the same time intervals sufficient to choose to receive the reverse channel from the receiver of a given number W HARQ-receipts coming in response to the first attempts of packets produced by the direct channel since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time.

In the preferred embodiment, the value S of the first metric is determined periodically at intervals sufficient to provide a reverse channel from the receiver of a given number of W1HARQ-receipts (W=W1), coming in response to the first attempts of packets produced by the direct channel since the previous calculation of the first metric or since starting work if the first metric is calculated in�the first, if all such HARQ-receipts are positive, or sufficient to obtain a given number of W2such HARQ-receipts (W=W2), if all such HARQ-receipts are not positive, or sufficient to obtain a given number of W3such HARQ-receipts (W=W3), in other cases, and W3≥W1>1 and W3≥W2>1.

Appropriate current value of the factor of gross compensation defined as the sum of its previous values and amendments C1factor gross compensation related to the value S of the first metric of functional dependence, which is in the field-increasing the allowable values of S the first metric that is bounded in modulus value of Δ1(-Δ1≤C1≤Δ1) and taking non-negative values (C1≥0) if S≤Stand non-positive values (C1≤0) if S≥Stwhere St- the target level of the first metric.

The range of allowable values of S the first metric, preferably, limit the interval 0≤S≤1, Stthe target level of the first metric is preferably selected in the range 0<St<1, amendment C1factor gross compensation related to the value S of the first metric, preferably, the relationship:

,

where Ssub> 1, S2, k1and k2are parameters such that 0≤S1≤St, St<S2≤1, S1/(S1+St)<k1≤St/(S1+St), St/(S2+St)<k2≤S2/(S2+St).

In this case, the value T of the second metric is desirable to determine immediately after receipt of a return channel from the receiver HARQ-receipts in response to the first attempt to transmit a packet on a direct channel.

Appropriate definition of the second metric to pause in the moment of changing the values of the factor of gross compensation and shall resume upon receipt of a return channel from the receiver HARQ-receipts in response to the first attempt of the packet produced by the direct channel after the previous calculation of the first metric.

The value T of the second metric is advisable to select equal "-Δ2"if the previous HARQ-receipt was positive or equal to Δ3if the previous HARQ-receipt was not positive, with Δ2>0 and Δ3>0, and the values Δ2and Δ3choose in accordance with the expression:

,

where Tt- the target level of the second metric (0<Tt<1).

The current value of the factor slim compensation is determined, preferably, as the sum of its previous value and the value T of the second metric.

<> Preferably, the initial value of the factor slim compensation was equal to zero, and the current value of the factor slim compensation is limited in magnitude by the value of Δ4equal to the value of Δ1limiting modulo amendment C1factor gross compensation.

In a preferred embodiment the value of the target level of Stthe first metric is equal in magnitude to the value of the target level Ttthe second metric (St=Tt).

It is desirable that the evaluation of the CQI, the gross factor compensation factor and slim compensation had the dimension of decibels.

Compensation of the offset of the CQI estimation is carried out, preferably, for each pair of transmitter-receiver or transmitter-subchannel, or for each three transmitter-receiver-subchannel in the case that the wireless communication system includes multiple transmitters or multiple receivers or multiple sub-channels.

Compensation of the offset of the CQI estimation is carried out, preferably, for each transmission mode in the case that the wireless communication system configured to implement multiple transfer modes used by different type of MIMO technology.

The technical result achieved when using the method of packet data in a wireless communication system according to the invention, is to provide high-precision and�optiunea control the level of successful packet transmission on the direct channel in a wide range of offset for CQI estimation, the efficiency of radio resources and data transmission speed in the forward channel, the quick transition to the steady-state mode of operation, and the ease and convenience of integration of the proposed solution with existing wireless communication systems with hybrid automatic repeated (HARQ), for example, communication systems such as LTE or WiMAX.

BRIEF description of the DRAWINGS

The invention is further illustrated by a description of specific variants of its implementation and the accompanying drawings, in which, according to the invention:

Fig.1 depicts an illustrative method of transmitting data in wireless communication system with HARQ for example, the mobile communication system LTE;

Fig.2 is a block diagram of a base station of the communication system shown in Fig.1;

Fig.3 is a structural block diagram of an adaptive choice of the CCM;

Fig.4 is a structural block diagram of the outer loop compensation;

Fig.5 - General view of the graphical dependence of amendments C1factor gross compensation from the value S of the first metric.

DETAILED DESCRIPTION

In any wireless communication system, the necessary balance between speed and noise immunity is achieved by encoding/decoding data using a particular set of code modulations (CCM), provides coverage for a wide range of code speed�th.

Choosing the most effective CCM carried out taking into account the assessment of the status of the communication channel. For example, if the channel is set by the process with additive white Gaussian noise, then its state is completely determined by the value of the ratio signal to noise ratio (SNR), which is often called the estimate of the channel quality (CQI). Spending for each of the CCM comparison threshold SNR, corresponding to a given threshold error level, with the current assessment of the quality of the channel, define the CCM, for which the threshold value of SNR is below assess the quality of the channel. Then from these CCMS choose one with the highest code rate. Selected CCM is used for error-correction encoding data and transmitting them over the communication channel to ensure delivery of data, the error rate is below the threshold and reach the highest utilization efficiency of radio resources.

In wireless communication systems, the channel state is time dependent, and broadband communication systems and the frequency (so-called frequency-selective channel). In this regard, assessment of the quality of the channel is carried out with a certain periodicity. In broadband communication systems quality assessment of the channel are often carried out independently of the components of its individual sub-channels, each of which is considered narrowband, i.e. without frequency selectivity. By performing Directors.�the second evaluation of the quality of the channel one or more of the received CQI values are quantized to ensure the representation in binary form and transmitted on the feedback channel to the transmitter.

For wireless communication systems, performed with MIMO, CQI estimate and is used when determining the best CCM for each spatial subchannel transmission.

In wireless communication systems, the SNR estimation in the transmission channel is performed on the receiver on the reference signals. The current value of the noise factor of the receiver in this case, as a rule, is unknown. Instead of the exact value of the noise factor using the approximate characteristic of this receiver value. In this regard, in the process of estimating the SNR discrepancies may occur with the real value of the SNR, leading eventually to the selection of less effective CCM, reducing the efficiency of use of radio resources and, consequently, reduced the speed of data transmission. Reduce the effectiveness of select CCMS also result in errors due to quantization and channel estimation, delay of communicating the evaluation, the channel variability in time due to multipath propagation of the signal, a random (or not random) impact of third-party transmitters, transmission subchannels with primarily the best estimation of the CQI, and many other factors. In fact, these factors lead to the appearance of bias assessment of the state of the channel relative to its true value. This offset may change over time according to some pseudo-random law, Kotor�th is unknown to the transmitter and receiver. The appearance of bias assessment CQI affects the choice of the CCM. In this case, the communication system cannot guarantee that the probability of unsuccessful transmission of the packet from the first attempt does not exceed the threshold level, which leads to an increase in the number of retries transmission (positive offset) or cannot guarantee optimal efficiency used by the CCM, which leads to high redundancy applied CCM (negative offset). In both cases, significantly reduces the use efficiency of radio resources and, as a consequence, the speed of data transfer.

Operational offset compensation estimation CQI at the transmitter can reduce the negative effect caused by this offset.

To detect and correct errors that occur during data transmission in wireless communication systems, mechanisms used automatic request retransmission (HARQ). To detect errors, each packet in the transmission is supplied by a checksum, computed by logical operations on data held in this package. Checksum code on the transmitter together with the rest of the data packet and decode on the receiver upon receipt of the package. After decoding the checksum is calculated by a similar logical operations on the decoded data and compare with accepted control� amount. In the case of coincidence of both checksums believe that the packet transmission was completed without errors, and inform the transmitter by transmitting on the reverse channel positive HARQ-receipts. In case of discrepancy between the checksums believe that the packet transmission was completed with an error, and inform the transmitter by transmitting on the reverse channel negative HARQ-receipts. On receiving a positive HARQ-receipts held transmitter attempt packet transmission is considered successful. Otherwise, consider that the attempted transfer of the package was executed poorly and perform the following try transfer the same data packet in accordance with the rules of the transmission Protocol. Also compare the number of transmission attempts of a packet with the maximum number of transmission attempts, at which the repeated attempts do not produce, and this package is cast.

Below is considered one of the preferred embodiments of the method of packet data transmission in wireless communication system with hybrid automatic repeated, according to the invention, the example LTE system, illustratively shown in Fig.1. In the LTE system, a base station 1 that transmits data on the direct channel 2, periodically receives the backward channel 3 from the receiving subscriber device receiver 4 message - CQ-reports 5, containing an assessment CQI channel quality 2. Data in the communication system LTE packets transmitted transport blocks (TV). Before the first TV transmission base station 1 performs adaptive selection of the CCM. In the framework of adaptive selection of the CCM base station 1 performs the offset compensation of the CQI estimation method disclosed below, and selects the most efficient coded modulation, which ensures that the probability of error at the first attempt transmission at the level of S not exceeding the threshold level Ston the basis of the current value of offset to the CQI estimation. Using the selected CCM base station 1 performs error-correction coding of the TV that contains data intended for transmission to the receiver 4. After performing encoding TV base station 1 carries out the first attempt to transmit encoded TV 6 channel 2. In response to a attempted transmission of TV 6 to the base station 1 from the receiver 4 via the backward channel 3 enters HARQ-receipt 7. If HARQ-receipt 7 in the affirmative, TV transmission is considered successful and the base station 1 proceeds to the transmission of the next TV, repeating all steps, starting from the offset to the CQI estimation. In case of receipt in response to the previous transmission attempt TV 6 negative HARQ-receipts 7 or no within a specific time� positive HARQ-receipts base station 1 carries out retransmission transmitting TV 6 channel 2. At the same time, if the implemented number of transmission attempts TV limit, its retransmission is not performed, the TV is dropped and the base station 1 proceeds to the transmission of the next TV, repeating all steps, starting from the offset to the CQI estimation.

In the LTE communication system selection CCM for data transmission via the channel 2 is the following. For transmission of the next TV base station 1 selects from among the 29 available the most effective CCM, i.e. with higher order modulation and the highest code speed, and at the same time showing the error probability of transmission of TV on the first attempt no higher than 1-St=0,1 (target probability of Stthe successful transfer of this TV at first attempt at least 0.9).

Enlarged block diagram of the base station 1 shown in Fig.2, includes a scheduler 8 assists, performing allocation of radio resources in the LTE system, and forming at its output 9 based on a predetermined scheduling policy schedule alarm transmission for forward and reverse channels 2 and 3 in each time interval planning. In particular, the scheduler carries out 8 assists scheduling of TV programmes, addressed to one or more receivers 4 channel 2, the scheduling of TV programmes on channel 3, and scheduling transmission of service data, including HARQ-quetant�th 7 and CQI-report 5 on channel 3. When planning transmission on direct TV channel 2 planner 8 assists for each TV defines the CCM by passing the CCM log 10 unit 11 adaptive choice of the CCM, which returns the scheduler 8 assists to its input 12 replies CCM that contains an indication of the most effective for CCM transmission of this TV. Schedule alarm transmission containing information about the selected line TV and CCM, is fed to the input of block 13 of acceptance, which generates the appropriate TV from custom data coming from upper layers, performs error-correction coding TV using the CCM and transmits the encoded TV channel 2.

Unit 13 acceptance LTE base station receives a reverse channel 3 from each receiver 4 wideband CQI reports containing quantized estimate CQI for direct 2 channel or narrowband CQI-reports containing quantized estimate CQI for a subchannel of channel 2 and HARQ-receipts showing the delivery status of the TV. Quantized estimate of the channel state information is retrieved from the CQI reports, and is supplied to the corresponding input of the processing unit 14 CQI. The resulting current CQI values for each receiver 4 are provided to the input 15 of the block 11 of the adaptive choice of the CCM.

The main purpose of HARQ-receipts 7 is the control of TV delivery and request repeat�th unsuccessful transmission transmitted TV. In addition, HARQ-receipts 7 is transmitted to the input 16 of the block 11 of the adaptive choice of the CCM that allows the unit 11 adaptive choice of the CCM to determine the presence of bias current value assessment CQI quality direct channel 2 and to generate a signal to compensate for this offset.

The main elements of the unit 11 adaptive choice of the CCM, the block diagram of which is shown in Fig.3 are block 17 of the inner loop adaptation and the block 18 of the outer loop adaptation. The CCM requests from the scheduler 8 transmission input 10 unit 11 and current CQI values from the processing unit 14 CQI received at the input 15 of the unit 11 are sent to the block 17 of the inner loop adaptation, and HARQ-receipts received at the input 16 of the unit 11 are sent to the block 18 of the outer loop adaptation.

On the basis of information about the status of TV delivery contained in the HARQ-the receipts received at the input 16 of the block 11 and then to the input unit 18, the latter determines the value of the gross factor compensation factor and a subtle offset to the CQI estimation, while at the outputs 19 and 20 are formed signals containing information about the current value of the factors of coarse and fine compensation, respectively. The said signals are fed to respective inputs of the block 17 of the inner loop adaptation.

Block 17 of the inner loop adaptation selects the most effective CCM on about�Enke can CQI, blended using factors of coarse and fine compensation as calculated by the block 18 of the outer loop adaptation. A signal carrying information about the selected CCM, is fed to the output 21 of the unit 11 adaptive selection of the CCM and then to the input 12 (Fig.2) scheduler 8 assists in response to the request of the CCM.

Block 18 of the outer loop adaptation, structural diagram of which is shown in Fig.4, contains the line 22 gross compensation and the thin line 23 compensation.

Line 22 gross compensation is designed to calculate the factor of gross compensation, characterizing the average offset of the CQI estimation at long time intervals and includes a calculation block 24 of the first metric S and the block 25 calculate the factor of gross compensation.

The thin line 23 compensation is designed to calculate the factor slim compensation characterizing the difference between the average value of the offset to the CQI estimation, computed in line 22 gross compensation, and the current value of offset to the CQI estimation, and includes the calculation unit 26 of the second metric T and the block 27 calculation factor slim compensation.

In line 22 gross compensation on the basis of the HARQ-receipts received from the receiver 4 via the backward channel 3 to the input 16 of the block 18 and then to the input unit 24 of the computation of the first metric, the establishment of the first metric of S, then the signal output unit 24 is supplied to BL�to 25, who is responsible for the calculation of RC factor gross payment received at the output 19 of the unit 18 of the outer loop adaptation and used to correct the offset of the CQI estimation.

In one embodiment, the first metric S is the empirical probability of successful transmission of TV on the first attempt, defined as the ratio of the number of successful first attempts at transmission of TV and total number of successful and unsuccessful first attempts at transmission of TV spent some time interval.

In this case, the first metric is determined based on the HARQ-receipts, signaling the success or failure of the first attempt to transfer TV, in accordance with the relationship:

,

where W is the number of HARQ-receipts received on the reverse channel from the receiver in response to the first attempt at transmission of TV, produced by the direct channel since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time, a Swas positive HARQ-receipts from this number.

Determining the value of the first metric is carried out periodically, in one embodiment of the method through equal intervals of time. The duration of the period is constant and does not depend on the number of W HARQ-receipts.

In another embodiment, determining the value of the first metric cher spend�h intervals, the length of which is variable and is determined by a given number W HARQ-receipts. This method allows to control the accuracy of determining the first metric and, in particular, to maintain it at the level of ~W-1due to the choice of parameter values W., To increase the accuracy should choose a larger value of W, however, the excessive increase in W can lead to the opposite effect by increasing the delay.

In yet another embodiment, the intervals also determine the number of W HARQ-receipts, but the period is completed ahead of schedule, if the beginning had been received W1<W HARQ-receipts and they were positive or if since the beginning of the period was obtained W2<W HARQ-receipts and they were all negative. In this case, the value of the first metric is determined equal to W1/W1=1 in the first case and 0/W1=0 in the second. Early termination of the period for determining the value of the first metric significantly reduces the time of transition in the steady-state mode of operation for early detection of extreme values of the first metric.

In block 25 the calculation of gross factor compensation is compared to the value S of the first metric with the target value of Stand according to the results of this comparison is the determining factor RC of gross compensation. When you change the value of the factor of gross compensation to the input 28 b�Oka 27 calculation factor slim compensation signal is reset.

Block 25 gross compensation calculates the current value of RC(t) factor gross compensation by changing its previous value RC(t-1) to the correction value C1factor gross compensation by the formula:

RC(t)=RC(t-1)+C1.

In this case, the correction value C1is determined by the comparison of the current value S of the first metric with the target value of St. If neocomposite (S≤St) the correction value C1choose non-negative, with overcompensation (S≥St) is nonpositive, and the absolute value of the amendment is greater, the greater the difference values S and Stthat allows you to organize the negative feedback on the value of |S-St| and to ensure control of the probability of success for first attempts transmission at the level of the St. In addition, high module amendments (C1limit parameter Δ1equal, in this example, the minimum difference threshold SNR used for CCM or proportional to the latter.

In particular, the correction value C1determined in accordance with the relationship:

where Δ1- high module amendments (C1, a S1, S2, k1and k2are parameters such that 0≤S1<St, St<S2≤1, S1/(S1+St)<k1≤St/(S1 +St), St/(S2+St)<k2≤S2/(S2+St).

Graphical view of the dependence of amendments C1factor gross compensation from the value S of the first metric showing all singular points are shown in Fig.5. It follows from the graph that for small S (S≈0), the correction value C1takes maximum positive value, the magnitude of the factor RC of gross compensation increases rapidly with time. Because the current assessment CQI channel quality is reduced by the value of RC, then the estimate of the channel state is also rapidly decreases, which is accompanied by more noise-CCM, through the use of which the probability of successful transmission of TV on the first attempt will increase. Fig.5 also shows that for large values of S (S≈1), the correction value C1takes the maximum negative value, while the value of the factor RC of gross compensation rapidly decreases with time. In turn, the estimation of the channel state is growing rapidly, accompanied by a selection of less noise-CCM, through the use of which the probability of successful transmission of TV on the first attempt will go down. When the value of the first metric S close to the target value (S≈St) the correction value C1is equal to zero. This means that the line 22 gross compensation came in a steady mode, in which� factor gross compensation is the optimal value. The parameters S1, S2, k1and k2determine the adjustment value, when the value of the first metric can be attributed neither to limit nor to the target. The initial value of RC(t=0) factor gross compensation is determined by practical considerations and, in particular, can be chosen equal to zero.

Line 23 (Fig.4) fine compensation is intended for the detection of factor FC slim compensation characterizing the difference between the average offset of CQI estimation and the current offset to the CQI estimation. In line 23 slim compensation based on the HARQ-receipts received from the receiver on the reverse channel to the input of the calculation unit 26 of the second metric, is the definition of T values of the second metric, which is input to the block 27 slim compensation. In block 27 the thin calculates the compensation factor FC slim compensation. If the input 28 of the block 27 slim compensation receives a reset signal from unit 25 to calculate the gross factor of compensation unit 27 slim compensation discharging factor slim compensation initial value, e.g. zero.

The thin line 23 compensation can more accurately compensate for the offset of the CQI estimation of the channel state within the accuracy provided by the line 22 of gross compensation, i.e. in the interval [-Δ1Δ1].

In the described var�ante perform the calculation unit 26 of the second metric determines the status of the HARQ-receipts directly at the moment of its receipt. If HARQ-receipt is received in response to the first attempted transmission of TV on the direct channel and since this TV not changes to the gross factor compensation, determination of the second metric. If the received HARQ-check is positive, the second metric T takes a negative value "-Δ2"otherwise, the second metric T takes a positive value for Δ3. The T value of the second metric is supplied to the unit 27 to calculate the factor slim compensation, taking into account the received signal determines the value of the factor FC slim compensation.

The calculation of the current value of FC(t) factor slim compensation is performed by modifying its previous value FC(t-1) by the amount T of the second metric by the formula:

FC(t)=FC(t-1)+T.

The arrival of a positive HARQ-receipts, indicating, perhaps, excessive noise immunity used CCM reduces the value of the factor slim compensation by the amount Δ2that leads to additional offset and a higher score CQI. This, in turn, leads to the selection of SCC, characterized by a higher code rate and lower immunity. On the contrary, the arrival of a negative HARQ-receipts, indicating, perhaps, a lack of immunity used by the CCM, soprovojdayuschaya factor values thin compensation by the amount Δ 3that lowers the value of compensation and evaluation of the CQI. This, in turn, leads to the selection of SCC, characterized by a lower code rate and higher noise immunity.

The parameter values Δ2and Δ3in the steady state (i.e. at the steady state value of the factor of gross compensation) determine the target level Ttthe second metric in accordance with the expression:

.

The initial value of FC(t=0) factor slim compensation can be chosen equal to zero, while the current value of the factor slim compensation limit modulo a constant Δ4equivalent in value to the parameter Δ1limiting modulo amendment C1factor gross compensation. This choice of constraints guarantees the thin line 23 compensation within the uncertainty of the characteristic line 22 gross compensation.

In a preferred embodiment of the method according to the invention, the target levels of the first and second metrics are the same, which guarantees the matching of the lines 22, 23 coarse and fine compensation in the steady state.

For example, when the target level of Stthe probability of TV delivery on the first attempt (first metric) equal to 0.9, have a target level of Ttthe second metric is also 0.9, where we get Δ3=9Δ 2. However, the correction values Δ2and Δ3limited to, at least, the value of Δ1but in practice they are chosen several times smaller the value of Δ1.

In a preferred embodiment of the method evaluation of the CQI, the gross factor compensation factor and slim compensation have dimensions decibels. The same dimension have the parameters Δ1That Δ2That Δ3and Δ4used for finding the offset of CQI estimation.

In an embodiment, the use of the proposed technical solutions in the LTE communication system, the value of Δ1choose equal to 1 dB, which corresponds to a minimum difference between the SNR thresholds used by the CCM. The value of Δ3chosen so that it was several times less than the value of Δ1. This allows as many times to increase the accuracy of compensation. The most practical is the selection of the value of about 0.18 dB. In this case, when the target value of the first and second metrics at the level of 0.9, the value of Δ2is about 0.02 dB. When consistent intake since the beginning of the period for determining the first metricΔ1Δ2=50positive HARQ-receipts factor thin the compensation povyshe�Xia to the limiting value Δ 1. In this case, the factor of gross compensation appropriate to modify (increase) ahead of time, so the parameter W1choose not greater thanΔ1Δ2. When consistent intake since the beginning of the period for determining the first metricΔ1Δ3=6negative HARQ-receipts factor slim compensation is reduced to the limiting value of-Δ1. In this case, the factor of gross compensation appropriate to modify (lower) ahead of time, so the parameter W2choose not the superiorΔ1Δ3. In the case of alternating positive and negative HARQ-receipts the value of the parameter W is chosen based on the required accuracy of determining the first metric. So when the accuracy of determining the first metric of about ±1% is required to receive at least W=100 HARQ-receipts.

The parameters S1, S2, k1and k2included in functional�iimost amendments C 1factor gross compensation from the value S of the first metric can be chosen quite arbitrarily within the constraints 0≤S1<St, St<S2≤1, S1/(S1+St)<k1≤St/(S1+St), St/(S2+St)<k2≤S2/(S2+St). Specific values of these parameters affect the range of values of the first metric in the steady state operation and the rate of occurrence in steady-state mode of operation.

1. A method of transmitting data in wireless communication system with hybrid automatic repeated (HARQ) and receiving from the receiver on the reverse channel message containing an assessment (CQI) quality of the direct channel, consisting in the fact that carry out offset compensation estimation CQI by processing the HARQ-receipts, on the basis of the compensated evaluation CQI chosen signal-to-code design (CCM), perform the encoding of a data packet, perform the first attempt to transmit a packet of encoded data to the receiver via the direct channel, the success of which is judged by referring to HARQ-receipts, received from the receiver on the reverse channel in response to this attempt, then if the previous HARQ-receipt was not positive, carry out at least one retransmission of the packet on a direct channel, characterized in that the com�instiu offset to the CQI estimation is performed by determining the first metric with the use, at least the last two HARQ-receipts, determine the value of factor gross compensation taking into account the value of the first metric, determining a second metric using at least one of the last HARQ-receipts, determine the value of factor slim compensation taking into account the value of the second metric, the operation of resetting the value of the factor slim compensation to the initial value when changing the current values of the factor of gross compensation, changes in the CQI estimation with the values obtained values of gross factor compensation factor and fine compensation.

2. A method according to claim 1, characterized in that the first metric is defined as the ratio of the number of successful first attempts to transmit packets to the total number of successful and unsuccessful first attempt to transmit packets.

3. A method according to claim 2, characterized in that the value S of the first metric is determined in accordance with the relationship:

where W is the number of HARQ-receipts received on the reverse channel from the receiver in response to the first attempts to transmit packets made since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time, a Swas positive HARQ-receipts from this number.

4. A method according to claim 3, characterized in that the value S of the first metric is determined pyo�eticheski, at equal intervals of time.

5. A method according to claim 3, characterized in that the value S of the first metric is determined periodically, at intervals sufficient to provide a reverse channel from the receiver of a given number W HARQ-receipts coming in response to the first attempts to transmit packets made since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time.

6. A method according to claim 3, characterized in that the value S of the first metric is determined periodically, at intervals sufficient to provide a reverse channel from the receiver of a given number of W1HARQ-receipts (W=W1), coming in response to the first attempts of packets produced by the direct channel since the previous calculation of the first metric or since starting work if the first metric is calculated for the first time, in the case that all such HARQ-receipts are positive, or sufficient to obtain a given number of W2such HARQ-receipts (W=W2), if all such HARQ-receipts are not positive, or sufficient to obtain a given number of W3such HARQ-receipts (W=W3), in other cases, and W3≥W1>1 and W3≥W2>1.

7. A method according to claim 1, characterized in that the current value of the gross factor �compensatie defined as the sum of its previous values and amendments C 1factor gross compensation related to the value S of the first metric of functional dependence, which is in the field-increasing the allowable values of S the first metric that is bounded in modulus value of Δ1(-Δ1≤C1≤Δ1) and taking non-negative values (C1≥0) if S≤Stand non-positive values (C1≤0) if S≥Stwhere St- the target level of the first metric.

8. A method according to claim 7, characterized in that the range of allowable values of S the first metric limit interval 0≤S≤1, Stthe target level of the first metric chosen in the range 0<St<1, amendment C1factor gross compensation related to the value S of the first metric dependence:

where S1, S2, k1and k2are parameters such that 0≤S1<St, St<S2≤1, S1/(S1+St)<k1≤St/(S1+St), St/(S2+St)<k2≤S2/(S2+St).

9. A method according to claim 1, characterized in that the value T of the second metric is determined immediately after receipt of a return channel from the receiver HARQ-receipts in response to the first attempt to transmit a packet on a direct channel.

10. A method according to claim 9, characterized in that the determination of the second meter�suspend Ki at the moment of changing the values of the factor of gross compensation and resume upon receipt of a return channel from the receiver HARQ-receipts in response to the first transmission attempt of the packet, produced by the direct channel after the previous calculation of the first metric.

11. A method according to claim 10, characterized in that the value T of the second metric is chosen equal "-Δ2"if the previous HARQ-receipt was positive or equal to Δ3if the previous HARQ-receipt was not positive, with Δ2>0 and Δ3>0, and the values Δ2and Δ3choose in accordance with the expression:

where Tt- the target level of the second metric (0<Tt<1).

12. A method according to claim 1, characterized in that the current value of the factor slim compensation defined as the sum of its previous value and the value T of the second metric.

13. A method according to claim 12, characterized in that the initial value of the factor slim determine compensation is zero, and the value of the factor slim compensation limit on module size Δ4equal to the value of Δ1limiting modulo amendment C1factor gross compensation.

14. A method according to any one of claims.1-13, characterized in that the value of the target level of Stthe first metric is chosen equal to the value of the target level Ttthe second metric (St=Tt).

15. A method according to claim 1, characterized in that the evaluation of the CQI, the gross factor compensation factor and slim compensation have dimensions of decib�L.

16. A method according to claim 1, characterized in that the offset compensation of the CQI estimation is performed for each pair of transmitter-receiver or transmitter-subchannel, or for each three transmitter-receiver-subchannel in the case that the wireless communication system includes multiple transmitters or multiple receivers or multiple sub-channels.

17. A method according to claim 16, characterized in that the offset compensation of the CQI estimation is performed for each transmission mode in the case that the wireless communication system configured to implement multiple transfer modes used by different type of MIMO technology.



 

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38 cl, 7 dwg

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1 dwg

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8 cl, 7 dwg, 2 tbl

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2 cl, 2 tbl

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