CN103120016B

CN103120016B - The low latency channel estimating of downlink mimo

Info

Publication number: CN103120016B
Application number: CN201080068602.0A
Authority: CN
Inventors: 胡旸; E.琼森
Original assignee: Ericsson China Communications Co Ltd
Current assignee: Ericsson China Communications Co Ltd
Priority date: 2010-06-16
Filing date: 2010-07-14
Publication date: 2016-06-08
Anticipated expiration: 2030-07-14
Also published as: CN103120016A

Abstract

When more than two-layer multiplexing in a CDM marshalling, it is necessary to two clusters in a subframe use the OCC of length 4. This means, it is impossible to utilize the channel estimating of the conventionally time slot one by one of scheme, and Doppler contribution cannot overcome. By being introduced in two time slots independently processing in subframe the dummy variable and pseudo channel sample used, and based on dummy variable applying frequency domain wave filter, being then based on pseudo channel sample and perform post processing, the process of time slot is likely to decrease the waiting time and overcomes Doppler contribution one by one. The code despreading of the OCC of length 4 no longer processes in the time domain, but processes in the frequency domain with two adjacent C DM groups. Therefore, frequency domain filtering can start earlier, thus reduces detection waiting time and the time of process of the length OCC more than 2. It can also be used to the OCC of length 2.

Description

The low latency channel estimating of downlink mimo

Technical field

Generally, the present invention relates to wherein to apply high-order mimo to support the low latency channel estimation methods of downlink multiple-input and multiple-output (MIMO) of multilayer transmission, equipment and system.

Background technology

Third generation partner program (3GPP) is responsible for the standardization of universal mobile telecommunications service (UMTS) system and Long Term Evolution (LTE). LTE is a kind of high speed technology based on packet communication for realizing all to reach high data rate at downlink and uplink direction, and is considered as the next generation mobile communication system of UMTS system. The LTE 3GPP carried out is worked also referred to as evolved universal terrestrial Access Network (E-UTRAN). The peak rate of 300Mbps, 5ms or less radio net can be provided to postpone also referred to as the first version of 3GPP version 8 or the LTE of Rel-8, the dramatically increasing and be designed to simplify network operation and reduce the network architecture of cost of spectrum efficiency. In order to support this kind of high data rate, LTE allows up to the system bandwidth of 20MHz. LTE can also be operated in different frequency bands, and can be at least functioning in FDD (FDD) and time division duplex (TDD). The modulation technique or the transmission plan that use in LTE are called OFDM (OFDM).

For the next generation mobile communication system of such as senior international mobile telecommunication (IMT) and/or the senior LTE senior (LTE-advanced) etc as the evolution of LTE, the support of bandwidth to up to 100MHz is just being discussed. Senior LTE can be counted as the version in future of LTE standard, and owing to it is the evolution of LTE, so backwards compatibility is important so that senior LTE can be deployed in the LTE spectrum taken. Also referred to as in the LTE of eNB or eNodeB and senior LTE radio base station, multiple antennas with precoding/beam forming technique can be used in providing high data rate to subscriber equipment (UE). Therefore, LTE and senior LTE (LTE-A) is the example of multiple-input and multiple-output (MIMO) radio system.Another example based on the system of MIMO is World Interoperability for Microwave Access, WiMax (WiMAX) system.

In the LTE-A also referred to as 3GPP version 10 or Rel-10, introduce 8 the UE specific reference signals altogether also referred to as demodulated reference signal (DM-RS) for the ease of channel demodulation. Reference signal is the known signal inserted in the precalculated position of OFDM time frequency grid. The existence of this known signal allows UE estimating down-ward link channel so that it can perform coherent channel demodulation. Therefore, the transmission of each downlink antenna port one DM-RS, this DM-RS are that antenna ports specifically and is that the UE pointed by transmission is specific. So far, it is stipulated that support the DM-RS pattern with general cyclic prefix (CP) of up to order 8. Cyclic Prefix is to protection interval additional before each OFDM symbol, in order to reduce intersymbol interference.

DM-RS signal transmits according to predefined pattern over time and frequency so that UE knows the position finding signal. Fig. 1 illustrates the DM-RS pattern with general cyclic prefix (CP) supporting up to order 8. Express " order " or transmission rank and represent the quantity that can pass through independent data stream that wireless channel reliably transmits or space layer. In the present context, order is understood to be the maximum quantity of the transmitting antenna port supported.

The general introduction of LTE downlink physical resource structure will be helpful to. In the ofdm system of such as LTE etc, available physical resources is divided into time and frequency grid. Time is divided into subframe, respectively includes multiple OFDM symbol. In LTE and senior LTE, the length of subframe is 1ms, is divided into two time slots of each 0.5ms. For general cyclic prefix (CP) length, the quantity of the OFDM symbol of each subframe is 14, and this represents time quantization is 14 symbols during subframe. For extended cyclic prefix length, there are 12 OFDM symbol in each subframe. Frequency is corresponding to the subcarrier in OFDM symbol, and the quantity of subcarrier changes according to the system bandwidth used. Each frame table in time frequency grid shows the single sub-carrier of a symbol phase, and is called Resource Unit (RE). The minimum schedulable unit of Resource Unit is called Physical Resource Block (PRB) or referred to simply as Resource Block (RB). In LTE and LTE-A, PRB crosses over 12 subcarriers and 0.5ms, i.e. 7 or 6 OFDM symbol, this depends on circulating prefix-length. Distribute PRB in the time domain in couples. Therefore, the LTE subframe of 1ms includes two PRB.

There is also the LTE subframe of the specific type being made up of three fields: down link pilot timeslot (DwPTS), protection period (GP) and uplink pilot time slot (UpPTS). This special subframe is for the downlink-uplink switching in tdd mode. The persistent period of GP field switches over, between receiving and sending, the time spent according to UE and also changes according to the signal propagation time from base station to UE. DwPTS field carries synchronization and user data and for transmitting scheduling and the downlink control channel of the information of control. Owing to total sub-frame duration is fixed on 1ms, so the persistent period of DwPTS and UpPTS field adjusted based on the persistent period of GP field.

Fig. 1 illustrates the time frequency grid of common LTE subframe. Each row in grid represents subcarrier, and each column represents OFDM symbol. Grid covers two LTE time slots, as mentioned above. The DM-RS pattern support of Fig. 18 DM-RS antenna port altogether.This pattern presents the DM-RS expense of every layer of 12 RE; That is, each antenna port will use 12 RE to transmit DM-RS signal. 8 DM-RS antenna port are separated by the combination of code division multiplexing (CDM) and frequency division multiplexing (FDM). It should be noted that, use term " antenna port " rather than " antenna " to not necessarily correspond to single physical antenna with what emphasize indication.

Retaining for DM-RS and organize into groups up to two CDM, wherein 12 RE are made up of by each CDM marshalling each PRB. CDM marshalling is for using the RE of the code division multiplexing reflex reference signal from multiple antenna ports to organize into groups. The square in Fig. 1, being marked with " 1 " forms a CDM marshalling, and the square being marked with " 2 " forms another CDM marshalling. Each CDM marshalling supports maximum four layers, i.e. maximum four antenna ports. Two CDM marshallings carry out multiplexing by FDM; In other words, the RE belonging to the first and second CDM marshallings transmits on different sub-carriers.

It can be seen that, there are two CDM clusters, a CDM cluster in each time slot. Additionally, each CDM marshalling includes three CDM groups. Each CDM group includes 4 RE in time domain, and in each CDM group, reusable is up to four DM-RS antenna port. RE in each group shares same sub-carrier at frequency domain. Such as, four squares being marked with " 1 " in the top line of the time frequency grid of Fig. 1 form a CDM group of CDM marshalling 1. The RE of the group on colleague indicates them to be carried by same sub-carrier mutually. It is also seen that different CDM groups are in the different rows of figure, the RE of the different CDM group of instruction carries on different sub-carriers.

The multiplexing of the reference signal in CDM group is by realizing across time domain application orthogonal covering codes (OCC). OCC is code set, and wherein the whole codes in set have zero cross-correlation. Therefore, employing will not interfere from two signals coded by two different codes of this set. One example of OCC is walsh code (Walshcode). Walsh code uses the walsh matrix of length N to define, i.e. have N row. Each row in walsh matrix is the walsh code of a length N. Although walsh code will be used for illustrating the present invention in the disclosure, but it is to be understood that can use any OCC.

Each antenna port, by OCC is applied to signal, transmits a reference signal in CDM group. If four antenna port multiplexings in CDM group, the then code of the OCC that each antenna port application of four antenna ports is corresponding with CDM group. As one, mode is described, the example provided is provided. The OCC of the length 4 of CDM group can be visualized as 4 �� 4 matrixes, and wherein each row of matrix represents the code of the OCC applied by respective antenna port. This allows separate at receiver-side and decode reference signal. Note, each CDM is organized into groups, use 4 �� 4 different matrixes.

In UE side, the estimation of every port channel performs by suitable OCC is used for each CDM group. Decode it is to say, each DM-RS signal uses for the corresponding OCC that signal is encoded. The OCC of different length is applied to channel estimating according to multiplexing how many layers in a CDM marshalling. The two kinds of exemplary scenario being respectively provided with two-layer and four layers are described now with reference to Fig. 2 and Fig. 3.

In CDM organizes into groups during multiplexing two-layer, the OCC of length 2 can be used for CDM cluster respectively in the first and second time slots, as shown in Figure 2. It means that the introduced Doppler contribution of mobility can by being weighted catching completely to two CDM clusters.When the mobility of UE is higher, time domain channel is likely to quickly change in time. Change it means that channel is likely between first and second time slot in subframe. Owing to the OCC of application length 2 means transaction code extension in each time slot, so the Doppler contribution between two time slots can by adopting the suitable coefficient of reflection actual channel condition to be weighted being fully compensated to two time slots.

When more than two-layer multiplexing in a CDM marshalling, it is necessary to two CDM clusters in a subframe use the OCC of length 4, as shown in Figure 3. The OCC of length 4 is generally used for high order situation. In UE side, the conventional strategy of one for performing the channel estimating based on DM-RS is that each PRB applies 2 �� 1D filtered method, i.e. first frequency domain filter, then time domain filtering. Ultimate principle shown in Fig. 4. Frequency domain filtering and time-domain filtering perform based on the corresponding input postponing extension, Doppler and reception signal. Generally, it was found that applying frequency domain wave filter is to process very much intensive, and thus require process time more longer than time domain filtering. Therefore, on significance degree, frequency domain filter required time becomes the bottleneck accelerated channel estimating and the process of detection further, and this can affect the whole detection waiting time.

When performing the channel estimating of OCC with length 2, as shown in Figure 2, it is possible to utilize the channel estimating of time slot one by one. In other words, the channel estimating based on the signal received in the first time slot can perform before the reception of whole subframe. Its reason is in that, reference signal transmits in two the continuous RE be in identical time slot, and reference signal to be decoded required all information in that single time slot be available. This allows in the first time slot by processing receiving before the reference signal in the second time slot required by frequency domain filter. This can cause low latency channel estimator.

But, in Rel-10, the OCC of length 4 is for supporting the multiplexing of up to four layers in each CDM marshalling, as mentioned above. When performing the channel estimating of OCC with length 4 as shown in Figure 3, code despreading cannot perform, until receiving whole subframe. This is because reference signal extends across four RE, wherein four RE are distributed in two time slots. Therefore, in conventional scheme, channel estimating cannot perform, until the signal received in two time slots. In other words, the process of the first time slot signal cannot start, until immediately receiving signal. Therefore, particularly additional period will be required by frequency domain filter. Therefore, low latency channel estimator is not suitable for the OCC of the length 4 of conventional scheme. It addition, when the OCC of length 4, Doppler contribution cannot be fully compensated, since it is desired that consider code despreading in two time slots.

Summary of the invention

This invention address that and include many problems that the normal channel of the problems referred to above is estimated. One non-limiting aspect of subject is for a kind of method being decoded for the reference signal for receiving in organizing into groups at code division multiplexing CDM, and wherein CDM marshalling includes at least two CDM group. Each CDM group receives on different sub-carriers, and each CDM group includes the Resource Unit in the first time slot and follow-up second time slot. In the method, the first set of the Resource Unit of each CDM group of at least two CDM group in the first time slot is received at subscriber equipment.Subscriber equipment can be applied to correspondence first set of Resource Unit of each CDM group of at least two CDM group and determine the dummy variable of the first time slot by will be applicable to the orthogonal covering codes in the first time slot, and it can be called again interim or intermediate variable. Subscriber equipment then can by or determine the pseudo channel sample of the first time slot based on the dummy variable that predetermined weighting matrix is applied to the first time slot, it can be called again interim or intermediate channels sample. The method is additionally included in the second set of Resource Unit that subscriber equipment receives each CDM group of at least two CDM group in the second time slot, be applied to correspondence second set of Resource Unit of each CDM group of at least two CDM group by will be applicable to the orthogonal covering codes in the second time slot and determine the virtual of the second time slot or interim or intermediate variable, and by or determine the virtual of the second time slot or interim or intermediate channels sample based on the dummy variable that predetermined weighting matrix is applied to the second time slot. Then subscriber equipment can determine the channel estimating of at least two CDM group based on the dummy variable of both the first and second time slots.

Another non-limiting aspect of subject is for a kind of subscriber equipment being suitable for and being decoded for the reference signal received in organizing into groups at code division multiplexing CDM, and wherein CDM marshalling includes at least two CDM group. Each CDM group receives on different sub-carriers, and each CDM group includes the Resource Unit in the first time slot and follow-up second time slot. Subscriber equipment can include communication unit, signal processing unit, frequency domain filter unit and time domain filtering unit. Communication unit can be set to receive the first set of the Resource Unit of each CDM group of at least two CDM group in the first time slot and the second set of the Resource Unit of each CDM group of at least two CDM group being configured to receive in the second time slot. Signal processing unit is disposed through the orthogonal covering codes that will be applicable in the first time slot and is applied to correspondence first set of Resource Unit of each CDM group of at least two CDM group and determines the dummy variable of the first time slot, and is arranged through the orthogonal covering codes that will be applicable in the second time slot and is applied to correspondence second set of Resource Unit of each CDM group of at least two CDM group and determines the dummy variable of the second time slot. Frequency domain filter unit is disposed through being applied to predetermined weighting matrix the dummy variable of the first time slot and determines the pseudo channel sample of the first time slot, and is arranged through the dummy variable that predetermined weighting matrix is applied to the second time slot and determines the pseudo channel sample of the second time slot. Time domain filtering unit can be set to determine the channel estimating of at least two CDM group based on the pseudo channel sample of both the first and second time slots.

Accompanying drawing explanation

By below in conjunction with accompanying drawing being discussed in greater detail preferred embodiment, the above-mentioned and other objects, features and advantages of the present invention will it is clear that in accompanying drawing, reference number represents the same section in each view. Accompanying drawing is not necessarily to scale.

Fig. 1 illustrates the demodulated reference signal mode in the subframe of OFDM physical resource structure with general cyclic prefix;

Fig. 2 and Fig. 3 illustrates the application of the orthogonal covering codes of length 2 that normal channel estimates and length 4;

Fig. 4 illustrates the principle of 2 �� 1D filter channel demodulating algorithm;

Fig. 5 illustrates the example of the low latency channel estimation methods of a non-limiting aspect according to the present invention;

Fig. 6 illustrates another example of the low latency channel estimation methods of a non-limiting aspect according to the present invention;

Fig. 7 illustrates a non-limiting example of the wireless communication system that wherein can implement low latency channel estimation methods; And

Fig. 8 illustrates the ability to perform a non-limiting example of the UE of channel estimating.

Detailed description of the invention

For the ease of illustrative rather than restrictive, it is proposed to the such as detail of particular architecture, interface, technology etc. It will be evident to one skilled in the art, however, that technology described herein also can be implemented in the other embodiments be different from these details. That is, although do not describe clearly herein or illustrate, but those skilled in the art can design various layout, these arrange the principle embodying described technology.

In some cases, the detailed description to well-known device, circuit and method is omitted, in order to avoid unnecessary details affects understanding of the description. All statement expectations of principle described herein, aspect, embodiment and example comprise 26S Proteasome Structure and Function equivalence. Additionally, it is contemplated that this kind of equivalents includes currently known equivalence and the equivalence of exploitation in the future, any unit performing identical function namely developed, and unrelated with structure.

It is thus possible, for instance, it will be understood that block diagram herein can represent the conceptual view of the illustrative circuit of the principle implementing this technology. Similarly, it will be understood that any flow chart, state transition diagram, false code etc. represent the various processes that substantially can be represented by computer-readable medium and be run by computer or processor, regardless of whether be explicitly illustrated this computer or processor.

Function including labelling or the various unit of the functional device being described as " processor " or " controller " can by specialized hardware and can run the hardware of associated software and provide. When being provided by processor, function can be able to be share or distributed multiple separate processor provides by single application specific processor, by single shared processing device or by some of them. In addition, the clearly use of term " processor " or " controller " is understood not to the hardware referring exclusively to run software, but can include digital signal processor (being abbreviated as " DSP ") hardware without limitation, be used for storing the read only memory (being abbreviated as " ROM ") of software, random access memory (being abbreviated as RAM) and Nonvolatile memory devices.

Subject mainly uses 3GPPLTE to describe in the exemplary embodiments. However, it should be noted that the principle of described theme can be widely applied to other communication system based on MIMO, for instance WiMAX, WCDMA or utilize the reference signal structure based on CDM any other based on the system of MIMO.

Accurate channel needed for providing the coherent demodulation of transmitted symbol is estimated and supports that low latency can be afoul target. Conventionally, in UE side, it is that each PRB applies 2 �� 1D filtering method based on the conventional strategy of the one in the channel estimating of DM-RS, i.e. first applying frequency domain wave filter, then applies time domain filtering, as mentioned above and as shown in Figure 4.

Also as discussed above and refer again to Fig. 2, when performing the channel estimating of OCC with length 2, the channel estimating of time slot can be used in reducing the waiting time one by one. In the channel estimating of time slot one by one, the channel estimating in the first time slot can perform before the reception of whole subframe. Can earlier be completed for the process that the signal received in the first time slot is filtered by frequency domain filter, be processed while the signal of transmission because it can work as to receive in the second time slot. This can cause low latency channel estimator.

But, when relating to the channel estimating of the OCC as shown in Figure 3 with length 4, it is impossible to perform the low latency channel estimating of this time slot one by one.Difference is in that, the code despreading of length 4 needs to wait until receiving whole subframe. Therefore, in conventional scheme, the first and second time slots all must be received before performing channel estimating.

The conventional scheme of the example of be described in detail during a CDM as being applied to senior LTE organizes into groups four layers. Referring again to Fig. 1, it can thus be seen that each CDM organizes into groups every PRB and includes three CDM groups. As it is shown on figure 3, when the length of OCC is 4, OCC crosses over the first and second time slots of subframe. In this case, for the n-th CDM group, wherein n is respectively equal to 1,2 and 3, and system model can be write:

In matrix equality (1), s_n,iIt it is the transmitted reference signal of i-th layer, i.e. the signal of the i-th antenna port. Each s_n,iIt can be QPSK (QPSK) symbol. For simplicity, each s_n,iIt is assumed to 1 in the present context. Each W_n,iRepresent the channel fading coefficient of i-th layer estimated in UE side. Additionally, each Y_n,jIt it is the reception signal of jth RE in the n-th CDM group of UE side. Here, the walsh code of length 4 is used for multiplexing four layers.

As discussed, when the multiple time slot of the length spans of OCC, conventional scheme only just starts channel estimating when receiving all time slots. Such as, in the OCC situation of length 4, channel estimation process only just starts when the signal received in both the first and second time slots, and the code despreading of the OCC of length 4 processes by following formula for the n-th CDM group:

In equation (2), eachRepresent W_n,iThe estimation of respective channels coefficient. It can be seen that, each in order to determine, it is necessary to receive whole signal Y_n,j, j=1,2,3,4. Therefore, it is impossible to execution channel estimation process, until also receive the second time slot.

Receiving whole Y_n,jAfter signal, frequency channels sample then can use weighting matrix G to adopt frequency domain filter to obtain, as follows:

In equation (3), G is N �� 3 matrix, and wherein N is generally certain number between 8 and 15. G is the matrix in frequency domain with weight coefficient, and it is determined by postponing extension input. Such as, G can be 12 �� 3 weighting matrixs when processing by PRB. Each _iIt it is the channel estimating of in frequency domain i-th layer.

By conventional scheme, the waiting time is likely to longer, because channel estimating cannot perform based on time slot one by one by the OCC code for crossing over multiple time slot. Therefore, inevitably, particularly extra time will be spent by frequency domain filter. Therefore, in conventional solution, low latency channel estimator is not suitable for the OCC situation of length 4, because the channel estimating of time slot one by one cannot be kept.

It addition, when the OCC of length 4, conventional scheme does not reflect Doppler contribution, because the code despreading of length 4 needs to come across two CDM clusters. In conventional method, the code across time domain extends the flat channel supposed in time domain. But, the introduced Doppler contribution of high mobility means that the hypothesis about the flat channel in time domain will not be set up. The code orthogonality that this means in time domain will not be set up. Additionally, cannot reflect in channel estimation or compensating for doppler impact.

One or more aspects of subject solve these and other shortcoming of normal channel estimation technique. According to one or more embodiments of the invention, code despreading can perform in each time slot, and so the weighting between latter two time slot can reflect or compensate the change channel in time domain. In one aspect, it is provided that equipment, system and/or method, wherein can for adopting the OCC the crossing over multiple time slots signal that receives encoded to perform the channel estimating of time slot one by one.It addition, can efficiently against Doppler contribution. The reception signal that the OCC that disclosed equipment, system and/or method can also be applied to could be used without crossing over multiple time slot encodes.

In one non-limiting, by adopting the process of the OCC the crossing over multiple time slots time slot one by one receiving signal encoded, low latency channel estimator is proposed. Returning to the OCC of the length 4 received on the first and second time slots in senior LTEDM-RS pattern shown in Fig. 1, the process of time slot can use the method 500 shown in Fig. 5 to realize one by one. In this accompanying drawing, it is assumed that UE receives the reference signal of the different time-gap transmitted from base station.

In step 510, the dummy variable of time slot is determined after receiving the signal of this time slot. The signal Y received in two time slots_n,jCan independent process as described below. By arranging for i=1 and 2And i=3 and 4 are arranged, then applicable equations (2), obtain following equalities:

1st time slot

2nd time slot

At equation (4a) and (4b), eachIt it is ' virtual ' variable of i-th layer of the n-th CDM group. Each dummy variable is regarded as the part code despreading of the part of the OCC using CDM group. Can remember, each Y_n,jIt it is the reception signal of the jth RE of the n-th CDM group. It can be seen that, the dummy variable in equation (4a)WithThe signal Y received during the first time slot can be based only on_n,1And Y_n,2Determine. Such as, for a CDM group, i.e. n=1, the first time slot dummy variableWithCan immediately receive signal Y_1,1And Y_1,2Determine afterwards, without the signal Y waited in the second time slot_1,3And Y_1,4. Similarly, second and the 3rd dummy variable of CDM group��WithAll can immediately receive signal Y_2,1��Y_2,2��Y_3,1And Y_3,2Determine afterwards.

Dummy variable in equation (4b)WithThe signal Y received during the second time slot can be based only on_n,3And Y_n,4Determine. In this particular example, the dummy variable of first, second, and third group of the second time slot��WithAll can immediately receive signal Y_1,3��Y_1,4��Y_2,3��Y_2,4��Y_3,3And Y_3,4Determine afterwards.

At second step 520, frequency domain filtering can perform by timeslot-based dummy variable, to determine the pseudo channel sample of time slot, as follows.

1st time slot

2nd time slot

Here, eachRepresent ' virtual ' channel samples of i-th layer. Pseudo channel sample is regarded as and uses the OCC of CDM group centre or the temporary variable being determined to realize frequency domain filtering. Dummy variable due to the first time slotWithCan for the dummy variable of each CDM group Yu the second time slotWithIndependently determine, so pseudo channel sampleWithCan with pseudo channel sampleWithIndependently determine. 12 �� 3 weighting matrix Gs identical with conventional scheme can be used. It can be seen that, with the estimation channel coefficients of conventional methodDifference, pseudo channel sampleCan determine based on time slot one by one.

In third step 530, time-domain filtering or other this post processing based on pseudo channel samplePerform, in order to draw the channel estimating of each i-th layer��

1st time slot

2nd time slot

About the channel estimating drawn by equation (6), it is possible to showing, they are identical with those channel estimating drawn by above-mentioned conventional scheme. This can pass through will for i=1 and 2And will for i=3 and 4Substitute into equation (5a) and (5b) with according toExpressAnd then willGained express substitute into equation (6) seen.

Once it is determined that pseudo channel sample, it is determined that channel estimatingIt is simple arithmetic operations, and substantially less processes intensive.Therefore, in one non-limiting embodiment, frequency domain filtering is performed based on time slot one by one, i.e. time slot determines pseudo channel sample one by one. Determine channel estimating, for instance, receiving the whole Ys corresponding with the length of OCC_n,jApply time domain filtering afterwards.

In another embodiment, channel estimatingAlso can determine by time slot one by one. Such as, channel estimatingWithCan based on the pseudo channel sample calculated in current transmission time interval (TTI)WithAnd based on calculating in previous TTIWithDetermine. Channel estimatingWithCan based on the pseudo channel sample all calculated in current TTI��WithDetermine.

Method shown in Fig. 5 is regarded as the general type of the method being decoded for the reference signal for receiving in organizing into groups performed by UE at CDM, and wherein CDM marshalling includes at least two CDM group. CDM group is the RE marshalling sharing same sub-carrier. Therefore, each CDM group is at corresponding received over subcarriers, and different CDM group receives on different sub-carriers. The reference signal of each CDM group can be carried on the Resource Unit of the first time slot and on the Resource Unit of follow-up second time slot.

One concrete non-limiting realization of the method is shown as method 600 in figure 6. In step 610, the first set Y of the Resource Unit of each CDM group that UE is able to receive that in the first time slot_n,j(such as Y_n,1And Y_n,2) on reference signal. In step 620, UE can be applied to the corresponding Resource Unit first of each CDM group and gather Y by will be applicable to the code of the OCC of the first time slot_n,j, it is determined that the dummy variable of layer i, i+1 of the first time slot, for instance in equation (4a)With. Then in step 630, UE can by being applied to the dummy variable of the first time slot by frequency domain filter, it is determined that the pseudo channel sample of layer i, i+1 of the first time slot, for instance in equation (5a)With. Pseudo channel sample, wherein G is predetermined weighting matrix, Yi JishiIt it is the vector of the dummy variable of each CDM group n.

Similarly, UE can receive the second set (such as Y of the Resource Unit of each CDM group of the second time slot in step 640_n,3And Y_n,4) on signal, determine dummy variable by will be applicable to correspondence second set of the Resource Unit that the code of the OCC of the second time slot is applied to each CDM group in step 650, for instance in equation (4b)With, and determine the pseudo channel sample of the second time slot in step 660, for instance in equation (5b)With. Although in most of the cases, step 630 and 660 can use identical predetermined weighting matrix G, it is contemplated that different matrixes can be used in those steps.

Must reaffirming, the dummy variable of the first time slot independently can be determined with the dummy variable of the second time slot. Therefore, in a preferred embodiment, the dummy variable of the first time slot is determined after receiving the signal transmitted in the first time slot, and unrelated with whether receiving and/or process the signal transmitted in the second time slot. Determine after the signal that the dummy variable of the second time slot transmits in receiving the second time slot. It means that the dummy variable of the first time slot can be determined during the second time slot or while receiving the signal transmitted in the second time slot, as performed shown in the parallel route of step 620 and 640.

The pseudo channel sample that the pseudo channel sample of the first time slot also is able to the second time slot is independently determined. Therefore, in a further advantageous embodiment, the pseudo channel sample of the first time slot is determined after determining the dummy variable of the first time slot, and unrelated with whether receiving and/or process the signal transmitted in the second time slot.The pseudo channel sample of the second time slot is determined after determining the dummy variable of the second time slot. It means that the pseudo channel sample of the first time slot can be determined while the signal of transmission during the second time slot or in receiving the second time slot, as shown in the parallel route of step.

Once the pseudo channel sample standard deviation of the first and second time slots is determined, i.e. when step 630 and 660 is complete, UE can determine channel estimating in step 670, for instance in equation (6)��With. Because starting simultaneously at of the signal that the frequency domain filtering of the signal transmitted in the first time slot can transmit in receiving the second time slot, so permission is shortened channel estimation latency by proposed exemplary method. It can be seen that, in Fig. 6 and also have the step in Fig. 5 to repeat, enabling perform to continue channel estimating. So, it is achieved the dynamically adapting to change condition and environment.

By the slight variations in equation (6), additionally it is possible to reflect Doppler contribution by weighting (namely between the first and second time slots) between two CDM clusters, as follows:

1st time slot

2nd time slot

In equation (7), c₁And c₂It is by the determined weight coefficient of doppler spread. Design factor is to reflect actual channel condition. In one embodiment, it is possible to weight coefficient is applied one or more restrictions. One restrictive condition can be weight coefficient and should be constant, for instance, c₁+c₂=C. Noting, equation (6) can be counted as the special circumstances of equation (7), wherein c₁=c₂=1. Therefore, specified conditions can be c₁+c₂=2, its senior LTE situation that can be applied to there is the OCC of length 4. Another restrictive condition that can apply is by ratioThe second time slot being set to and comprise from community interested and any RE of the known signal in given Transmission Time Interval (TTI) or subframe with same intensity or known strength is proportional to the amplitude ratio of the first time slot. This conditions permit is because of the recovery of Doppler's decay or the property of orthogonality of the pilot frequency mode of doppler spread and partial loss. It is of course possible to apply multiple restrictive condition simultaneously.

Shown in Fig. 5 and Fig. 6 and in the process described above 500 and 600, OCC can be walsh code. However, it is also possible to use other orthogonal code, for instance based on the orthogonal code of DFT.

Fig. 7 illustrates the wireless communication system that wherein can implement said method and apparent variant thereof. System 700 includes base station 710 and the UE720 of such as eNodeB etc. For brevity and clarity, a base station 710 and a UE720 are only shown. However, it should be noted that consider multiple base station and multiple UE completely.

Base station 710 preferably includes multiple antenna port 715, and each antenna port therein can be used in sending with UE720 and/or receiving radio signal. Although illustrating four antenna ports 715, but actual quantity being not limited thereto. As discussed, antenna port is logical expressions, and not necessarily correspond to single physical antenna. Antenna port may correspond to one or several physical antenna. It addition, each physical antenna may correspond to one or several antenna port.

UE720 also includes at least one antenna port 725 for sending and receive signal with base station 710. Although only illustrating an antenna port 725, but the actual quantity of antenna port 725 being not limited thereto.

Generally, base station sends reference signal DM-RS in specified RE, and UE performs channel estimating based on from base station received signal, as described in for said method. Fig. 8 illustrates the ability to perform an embodiment of the UE of channel estimating.The UE720 with channel estimation ability includes control unit 810, communication unit 820, memory element 830, signal processing unit 840, frequency domain filter unit 850 and time domain filtering unit 860 etc. Control unit 810 is arranged through control unit 820,830,840,850 and 860 to control the disposed of in its entirety of UE720, in order to provide a user with communication service.

The base station that communication unit 820 is arranged to wireless network communicates, and includes being operatively connected to antenna port 725 for the one or more wireless transceiver (not shown) sending and receiving signal of communication with base station.

Memory element 830 is arranged to the information needed for the operation of storage UE720, and also can store software code, and software code allows other unit including signal processing unit 840, frequency domain filter device unit 850 and Temporal filtering unit 860 to be operated. Signal processing unit 840 is arranged to step 510 and corresponding equation 4a, 4b to determine the dummy variable of each time slot. Frequency domain filter unit 850 is arranged to step 520 and corresponding equation (5a), (5b) determine the pseudo channel sample of each time slot. Additionally, time domain filtering unit 860 is arranged to step 530 and channel estimating is determined in equation (6), (7).

Although unit is illustrated by frame separately, but one or more unit can be embodied as integrated unit. Such as, signal processing unit 840, frequency domain filter unit 850 and time domain filtering unit 860 can all be combined in single integrating device. As another example, memory element 830 can store the one or more unit realizing unit 840,850 and 860 and the software code run by processing unit or the processor of UE wherein. In general, some or all of unit can be realized by the various combinations of hardware, software and fastener components. Component software can be stored in memory element 830 according to nonvolatile form.

Although above description comprises many details, but they are understood not to restriction the scope of the present invention, and are only to provide the explanation of a part of currently preferred embodiment of the present invention. Thus, it is to be understood that the scope of the present invention completely includes the apparent other embodiments of those skilled in the art, and correspondingly it is not meant to limit the scope of the present invention. All 26S Proteasome Structure and Function equivalences of the unit of above preferred embodiment known to persons of ordinary skill in the art are expressly incorporated into herein by reference, and estimate to be included in herein. Additionally, be not necessarily intended to device or method to solve as herein described or managed solution by this technology each problem, because it will be contained in herein.

Claims

1. the method (600) being decoded for the reference signal for receiving in organizing into groups at code division multiplexing CDM, described CDM marshalling includes at least two CDM group, each CDM group receives on different sub-carriers, each CDM group includes the Resource Unit in the second time slot after the first time slot and described first time slot, and described method includes:

First set of the Resource Unit of each CDM group of the described at least two CDM group in subscriber equipment reception (610) described first time slot;

It is applied to correspondence first set of Resource Unit of each CDM group of described at least two CDM group by will be applicable to the orthogonal covering codes in described first time slot by described subscriber equipment and determines the dummy variable of (620) described first time slot;

Determine the pseudo channel sample of (630) described first time slot by predetermined weighting matrix being applied to the dummy variable of described first time slot by described subscriber equipment;

Second set of the Resource Unit of each CDM group of the described at least two CDM group in described subscriber equipment reception (640) described second time slot;

It is applied to correspondence second set of Resource Unit of each CDM group of described at least two CDM group by will be applicable to the orthogonal covering codes in described second time slot by described subscriber equipment and determines the dummy variable of (650) described second time slot;

Determine the pseudo channel sample of (660) described second time slot by described predetermined weighting matrix being applied to the dummy variable of described second time slot by described subscriber equipment; And

Determine the channel estimating of (670) described at least two CDM group based on the pseudo channel sample of described both first and second time slots by described subscriber equipment.

2. the method for claim 1 (600), wherein, the dummy variable of the dummy variable of described first time slot and described second time slot is independently determined.

3. as the method for any one of the preceding claims (600), wherein, the dummy variable of described first time slot receives while described the second of Resource Unit is gathered in described second time slot to be determined, and the dummy variable of described second time slot is determined after described second set receiving Resource Unit.

4. method (600) as claimed in claim 1 or 2, wherein, the pseudo channel sample of the pseudo channel sample of described first time slot and described second time slot is independently determined.

5. method (600) as claimed in claim 1 or 2, wherein, the pseudo channel sample of described first time slot receives while described the second of Resource Unit is gathered in described second time slot to be determined, and the pseudo channel sample of described second time slot is determined after determining the dummy variable of described second time slot.

6. method (600) as claimed in claim 1 or 2, wherein, determine at the pseudo channel sample based on described first time slot and the second time slot that the step (670) of the channel estimating of described at least two CDM group includes the pseudo channel sample of described first and second time slots is weighted.

7. method as claimed in claim 1 or 2, wherein

The length of the described orthogonal covering codes of each CDM group is 4,

Y_n,1And Y_n,2It it is described first set of the Resource Unit of each CDM group of described at least two CDM group n;

WithBe according toThe dummy variable of determined described first time slot,

WithBe according to��The pseudo channel sample of determined described first time slot,

G is described predetermined weighting matrix,

Y_n,3And Y_n,4It it is described second set of the Resource Unit of each CDM group of described at least two CDM group n;

WithBe according toThe dummy variable of determined described second time slot,

WithBe according to��The pseudo channel sample of determined described second time slot, and

��WithBe according to��Determined described channel estimating,

Wherein c₁And c₂It it is weight coefficient.

8. method as claimed in claim 7, wherein,��WithDetermine while described second set of the Resource Unit in receiving described second time slot, and��WithDetermine after described second set receiving Resource Unit.

9. method as claimed in claim 7, wherein, c₁And c₂Sum is predetermined constant, and/or ratioDescribed second time slot of the predetermined resource unit being set to and comprise the known signal from base station is proportional to the amplitude ratio of described first time slot.

10. the applicable subscriber equipment (720) that the reference signal received in organizing into groups at code division multiplexing CDM is decoded, described CDM marshalling includes at least two CDM group, each CDM group receives on different sub-carriers, each CDM group includes the Resource Unit in the second time slot after the first time slot and described first time slot, and described subscriber equipment includes:

Communication unit (820), first set of the Resource Unit of each CDM group of the described at least two CDM group being configured to receive in described first time slot, and the second set of the Resource Unit of each CDM group of the described at least two CDM group being configured to receive in described second time slot;

Signal processing unit (840), it is arranged through the orthogonal covering codes that will be applicable in described first time slot to be applied to correspondence first set of Resource Unit of each CDM group of described at least two CDM group and determine the dummy variable of described first time slot, and the dummy variable of described second time slot is determined in correspondence second set of Resource Unit of each CDM group being applied to described at least two CDM group by will be applicable to the orthogonal covering codes in described second time slot;

Frequency domain filter unit (850), it is arranged through the dummy variable that predetermined weighting matrix is applied to described first time slot to determine the pseudo channel sample of described first time slot, and determines the pseudo channel sample of described second time slot by described predetermined weighting matrix being applied to the dummy variable of described second time slot; And

Time domain filtering unit (860), is arranged to determine the channel estimating of described at least two CDM group based on the pseudo channel sample of described both first and second time slots.

11. subscriber equipment (720) as claimed in claim 10, wherein, described signal processing unit (840) is suitable for the dummy variable with described second time slot and independently determines the dummy variable of described first time slot.

12. the subscriber equipment (720) as described in claim 10 or 11, wherein, described signal processing unit (840) determines the dummy variable of described first time slot while being adapted at described second set that described communication unit (820) is just receiving Resource Unit in described second time slot, and determines the dummy variable of described second time slot after being adapted at described second set that described communication unit (820) receives Resource Unit.

13. the subscriber equipment (720) as described in claim 10 or 11, wherein, described frequency domain filter unit (850) is suitable for the pseudo channel sample with described second time slot and independently determines the pseudo channel sample of described first time slot.

14. the subscriber equipment (720) as described in claim 10 or 11, wherein, described frequency domain filter unit (850) determines the pseudo channel sample of described first time slot while being adapted at described second set that described communication unit (820) is just receiving Resource Unit in described second time slot, and determines the pseudo channel sample of described second time slot after being adapted at the dummy variable that described signal processing unit (840) determines described second time slot.

15. the subscriber equipment (720) as described in claim 10 or 11, wherein, described time domain filtering unit (860) fits through the pseudo channel sample to described first and second time slots and is weighted determining the channel estimating of described at least two CDM group.

16. the subscriber equipment (720) as described in claim 10 or 11, wherein

The length of the described orthogonal covering codes of each CDM group is 4,

WithBe according toThe dummy variable of determined described first time slot,

G is described predetermined weighting matrix,

WithBe according toThe dummy variable of determined described second time slot,

��WithBe according to��Determined described channel estimating,

Wherein c₁And c₂It it is weight coefficient.

17. subscriber equipment (720) as claimed in claim 16, wherein, described signal processing unit (840) and described frequency domain filter unit (850) are determined while being adapted at described second set that described communication unit (820) is just receiving Resource Unit in described second time slot��With, and determine after described second set receiving Resource Unit��With��

18. subscriber equipment (720) as claimed in claim 16, wherein, c₁And c₂Sum is predetermined constant, and/or ratioDescribed second time slot of the predetermined resource unit being set to and comprise the known signal from base station is proportional to the amplitude ratio of described first time slot.