CN104025526A - Method and apparatus for antenna calibration - Google Patents

Abstract

Methods and apparatuses for calibrating antennas among multiple BS (Base Stations) s have been disclosed. A method for calibrating antennas between a first BS and a second BS is provided. The method comprises: obtaining UL (Uplink ) CSI (Channel State Information) of the first BS based on a SRS (Sounding Reference Signal) sent from a UE (User Equipment); obtaining UL equivalent CSI of the second BS via a weighted SRS sent from the UE. The weighted SRS is weighted with a ratio of DL (Downlink) CSI of the first BS to that of the second BS. The method further comprises calculating an ambiguity factor between the first BS and the second BS based on the UL CSI of the first BS and the UL equivalent CSI of the second BS. Then, the ambiguity factor may be used for calibrating the antenna between the two BSs.

Description

Method and apparatus for antenna calibration

Technical field

Embodiments of the invention relate generally to communication system, and relate more particularly to method, device, base station, subscriber equipment and computer program for boresight antenna between a plurality of base stations.

Background technology

This part has been introduced and may have been helped to promote the each side to (a plurality of) better understanding of the present invention.Therefore, the statement of this part will be read from this angle and will be understood to what belonging to prior art about or what does not belong to admitting of prior art.

The abbreviation and the term definition that appear in this specification and accompanying drawing are as follows.

3GPP third generation partner program

BS base station

CoMP works in coordination with multiple spot

CSI channel condition information

DL down link

FDD Frequency Division Duplexing (FDD)

ICI presence of intercell interference

LTE Long Term Evolution

LTE-A Long Term Evolution-senior

SRS detection reference signal

TDD time division duplex

UE subscriber equipment

UL up link

UTRAN universal terrestrial radio access network

In LTE-senior (LTE-A) system, (it is also referred to as collaborative multiple spot (CoMP) transmission is a kind of promising technology in order to reduce presence of intercell interference (ICI) and to improve the system spectral efficiency in cellular network, especially for multiaerial system in base station collaboration transmission.

In LTE and LTE-A system, there are two kinds of dual-modes, Frequency Division Duplexing (FDD) (FDD) and time division duplex (TDD).Channel reciprocity has been regarded as TDD system with respect to one of major advantage of FDD system, because the up link in TDD system and down link are shared identical frequency band.In other words, base station (BS) can for example, carry out estimating uplink channel information by the training sequence via transmitting from subscriber equipment (UE) (, detection reference signal (SRS)), to predict downlink channel information.Yet, uplink channel in TDD system and the reciprocity between downlink channel only guaranteed for spatial channel, and it is invalid due to the mismatch of radio frequency (RF) chain using in the reception for each antenna and transmission in actual system.

Fig. 1 shows for illustrating the uplink channel of TDD system and the signal mode of the nonreciprocity between downlink channel.

As shown in Figure 1, for each antenna in BS or in UE, its RF chain comprises high power amplifier (HPA) and the low noise amplifier (LNA) for receiving for transmitting.Transmission-receiving key is arranged between transmission and reception and switches.Therefore, the equivalent channel between BS base band and UE base band comprises HPA, spatial channel and LNA.As mentioned above, spatial channel is ideally reciprocity.

Get i antenna in UE and the channel between j antenna in BS as example.Order with represent respectively the gain of HPA and the gain of LNA of j antenna in BS, with represent the gain of HPA and the gain of LNA of i antenna in UE, and c _ijrepresent i antenna in UE and the spatial channel between j antenna in BS.So, equivalent uplink channel and equivalent downlink channel can be expressed as:

$g_{\mathrm{ij}}^{\mathrm{UL}}=S_i^{\mathrm{UE}}\·c_{\mathrm{ij}}\·Y_j^{\mathrm{BS}}---\left(1\right)$

$g_{\mathrm{ij}}^{\mathrm{DL}}=S_j^{\mathrm{BS}}\·c_{\mathrm{ij}}\·Y_i^{\mathrm{UE}}---\left(2\right)$

Order with refer to respectively in UE and BS in chain and the gain ratio of receive chain.So, the relation between uplink channel and downlink channel can be expressed as:

$g_{\mathrm{ij}}^{\mathrm{DL}}=\frac{{\mathrm{\γ}}_j^{\mathrm{BS}}}{{\mathrm{\γ}}_i^{\mathrm{UE}}}\·g_{\mathrm{ij}}^{\mathrm{UL}}---\left(3\right)$

Wherein be called as reciprocity error.

Because the character of RF chain can be along with variations such as temperature, humidity, so be necessary in order to utilize fully channel reciprocity, antenna calibration.

Self calibration is a kind of popular antenna calibration method using in single cell system.Utilize a kind of so method, the reciprocity error of each antenna in same BS is calibrated to same reference value.Fig. 2 illustrates the self-alignment method for two antennas of BS.

As shown in Figure 2, in piece 201, generate calibrating signal (for example=1).This calibrating signal be transferred to as indicated in piece 202, by the amplifier of two antennas that are calibrated (that is, LNA and HPA).Then, two signals (for example=1.1 and 1.2) are received and are saved in piece 203.The amplifier that this means these two antennas has different gains.Afterwards, in piece 204, the ratio between the gain of the amplifier of these two antennas is calculated and is saved.In illustrated example, this ratio is 1.1/1.2 ≈ 0.92.Subsequently, this ratio can be used to calibrate this two antennas.Particularly, in piece 205, the first antenna can directly transmit data, and the second antenna can transmit data by being multiplied by this ratio (that is, 0.92).

Illustrated method can expand to three or more antennas in BS, and wherein the gain of all antennas is calibrated to reference value (for example, the gain of the first antenna).

Yet, for example, in multi-cell cooperating system,, in CoMP system, wherein a plurality of BS are as single super BS to alleviate presence of intercell interference, and the self calibration of carrying out separately at each BS place is by the Gain Fuzzy causing between all cooperation BS, and it seriously worsens systematic function.

A kind of air interface calibration steps between a plurality of BS is proposed, to recover channel reciprocity.In a kind of so method, subscriber equipment (UE) feeds back to estimated downlink channel information by a plurality of BS that are calibrated via a limited number of bit.Then, the downlink channel information of these BS based on feeding back from these UE and estimated uplink traffic channel information, calibrate the gain ratio of transmission-receive chain of their all antennas.

Yet, due to channel estimation errors and feedback error, utilize air interface calibration steps described above to be still difficult to recover up link in TDD CoMP system and the channel reciprocity between down link.Further, these errors will greatly affect systematic function.

Summary of the invention

Therefore,, in the art by expectation, be provided for the solution of boresight antenna between at least two base stations.Also, by expectation, provide a kind of method, by the BS in the method TDD CoMP system, can calibrate exactly their antenna and not make system performance degradation.

In order to solve better the one or more focus in focus above, in a first aspect of the present invention, provide a kind of method for boresight antenna between the first base station (BS) and the second base station BS.The method can comprise: the training sequence based on sending from subscriber equipment (UE), obtains the uplink traffic channel information of a BS; Via the training sequence being weighted sending from this subscriber equipment, obtain the up link equivalent channels information of the 2nd BS, wherein the ratio of the downlink channel information by the downlink channel information with a BS and the 2nd BS carrys out this training sequence of weighting, obtains the training sequence that this is weighted; And the up link equivalent channels information of the uplink traffic channel information based on a BS and the 2nd BS, calculate the fuzzy factor between a BS and the 2nd BS, wherein this fuzzy factor is used to calibrate the antenna at least one BS in a BS and the 2nd BS.

In certain embodiments, at least one BS in a BS and the 2nd BS can comprise a plurality of antennas, and the plurality of antenna is calibrated by self-calibration process.

In certain embodiments, calculating fuzzy factor can comprise: the up link equivalent channels information of the uplink traffic channel information based on a BS and the 2nd BS that obtains by a plurality of subscriber equipmenies and/or in a plurality of image duration, and combine and estimate this fuzzy factor.

In certain embodiments, this subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and a link BS and two BS higher than predetermined threshold.

In certain embodiments, this training sequence of weighting can comprise: by amplitude and/or the phase place of the ratio of the downlink channel information of a BS and the 2nd BS, carry out this training sequence of weighting.

In a second aspect of the present invention, provide a kind of method of assisting two antenna calibrations between base station for subscriber equipment.The method can comprise: training sequence is transferred to this two base stations; Estimate the downlink channel information of these two base stations; With the ratio of the downlink channel information of these two base stations, carry out this training sequence of weighting; And the training sequence being weighted is transferred to at least one base station of serving this subscriber equipment in these two base stations.

In certain embodiments, this subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and links this two base stations higher than predetermined threshold.

In certain embodiments, this subscriber equipment repeats this estimation, weighted sum transmission in a plurality of image duration.

In certain embodiments, this estimation is based on from these two training sequences that base station sends.

In a third aspect of the present invention, the various embodiment of a kind of method that device implements a first aspect of the present invention are provided.Particularly, provide a kind of device for boresight antenna between a BS and the 2nd BS.This device can comprise: acquiring unit, be configured to the uplink traffic channel information that training sequence based on sending from subscriber equipment obtains a BS, and via the training sequence being weighted sending from this subscriber equipment, obtain the up link equivalent channels information of the 2nd BS, the training sequence that wherein ratio of the downlink channel information by the downlink channel information with a BS and the 2nd BS comes this training sequence of weighting to be weighted to obtain this.This device may further include: computing unit, be configured to uplink traffic channel information based on a BS and the up link equivalent channels information of the 2nd BS, calculate the fuzzy factor between a BS and the 2nd BS, wherein this fuzzy factor is used to calibrate the antenna at least one BS in a BS and the 2nd BS.

In a fourth aspect of the present invention, the various embodiment of a kind of method that device implements a second aspect of the present invention are provided.Particularly, provide a kind of device of assisting two antenna calibrations between base station for subscriber equipment.This device can comprise: transmission unit, is configured to training sequence to be transferred to this two base stations; Estimation unit, is configured to estimate the downlink channel information of these two base stations; And weighted units, be configured to carry out this training sequence of weighting with the ratio of the downlink channel information of these two base stations; Wherein this transmission unit is further configured to the training sequence being weighted to be transferred at least one base station of serving this subscriber equipment in these two base stations.

In a fifth aspect of the present invention, a kind of device is provided, this device comprises at least one processor and comprises at least one memory of computer program code.This memory and this computer program code are configured to: impel this device to carry out the embodiment of the method for a first aspect of the present invention, or the embodiment of the method for a second aspect of the present invention.

In a sixth aspect of the present invention, a kind of computer program is provided, this computer program comprises at least one computer-readable recording medium with computer readable program code part stored thereon.This computer readable program code partly comprises: for carrying out the code instructions of the embodiment of method of a first aspect of the present invention or the embodiment of the method for a second aspect of the present invention.

In a seventh aspect of the present invention, a kind of equipment is provided, this equipment comprises: for implementing the device of each step of method of a first aspect of the present invention or each step of the method for a second aspect of the present invention.

The specific embodiment of the theme described in this specification can be implemented, to realize the one or more advantages in following advantages.

The specific embodiment that utilizes the technology described in this specification, antenna can be calibrated between a plurality of BS.Further, by the feedback via weighting detection reference signal (SRS), because the feedback error quantizing or limit bit causes can be left in the basket and feedback overhead can be reduced.Therefore, by the fuzzy factor between the caused a plurality of BS of self calibration, can be calibrated.Proposed solution can be used in TDD CoMP system, does not make system performance degradation to recover channel reciprocity.

When read in conjunction with the accompanying drawings, other feature and advantage of embodiments of the invention are also understood the description by following specific embodiment, and these accompanying drawings illustrate the principle of embodiments of the invention by way of example.

Accompanying drawing explanation

By way of example, according to following the detailed description and the accompanying drawings, aspect, feature and the benefit with other above of various embodiment of the present invention will become obvious more fully, in the accompanying drawings:

Fig. 1 shows for illustrating the uplink channel of TDD system and the signal mode of the nonreciprocity between downlink channel;

Fig. 2 illustrates the self-alignment method for two antennas of BS;

Fig. 3 illustrates exemplary signal flow process according to an embodiment of the invention;

Fig. 4 illustrates the comparison of the simulation result of various calibration stepss;

Fig. 5 illustrates the exemplary process diagram of method 500 according to an aspect of the present invention;

Fig. 6 illustrates the exemplary process diagram of method 600 according to another aspect of the present invention;

Fig. 7 is the schematic block diagram that can be configured to the device 700 of implementation exemplary embodiment according to an aspect of the present invention;

Fig. 8 is the schematic block diagram that can be configured to the device 800 of implementation exemplary embodiment according to another aspect of the present invention;

Fig. 9 is suitable for carrying out according to the schematic block diagram of the BS using in exemplary embodiment of the present invention and UE;

The element that similar reference number in various accompanying drawings is similar with indicating indication.

Embodiment

Below, with reference to illustrational embodiment, principle of the present invention and spirit are described.Should be appreciated that these all embodiment only understand better for those skilled in the art and further carry out the present invention and be presented, and limit the scope of the invention and be not used in.For example, being used as the part diagram of an embodiment or the feature of describing can use together with another embodiment, to produce further embodiment.For clearness, all features of actual execution mode are not described in this specification.Certainly will recognize, in the exploitation of any such practical embodiments, should make many execution modes and specifically determine to realize developer's specific objective, such as relevant to system and with the restriction of traffic aided, this will change from a kind of execution mode to another kind of execution mode.In addition, will recognize, such development may be complicated and time-consuming, but will remain conventional task for the those skilled in the art who obtains the benefit of present disclosure.

Referring now to accompanying drawing, disclosed theme is described.Various structures, system and equipment are only schematically described in the accompanying drawings for the object of explaining, thereby and need not this to be described to the known details of those skilled in the art hard to understand.Yet accompanying drawing is included to describe and explain the illustrated examples of disclosed theme.The word using herein should be understood with being interpreted as and have with those skilled in the relevant art the consistent implication of the understanding of these words and phrase with phrase.By the term to herein or the consistency of phrase, use, be not intended to specifically defined to this term or phrase of hint, that is, and common different with the conventional implication definition of understanding from those skilled in the art.At term or phrase, be intended to have particular meaning (, the implication different from the implication of being understood by technical staff) aspect, specifically defined will be in specification clearly elaboration in the mode of definition like this, the mode of this definition directly and clearly provides specifically defined for this term or phrase.

As mentioned previously, in multi-cell cooperating system, the self calibration of carrying out separately at each BS place has caused the Gain Fuzzy between a plurality of BS, and it seriously worsens CoMP systematic function.

In proposed solution, one or more UE can be selected in this disclosure, to assist or to support the calibration between a plurality of BS.Each UE can via training sequence (for example, SRS) feed back its downlink channel information, this by get rid of as in previous described air interface calibration steps, occur by the feedback error quantizing or limit bit causes.Particularly, each UE can send the SRS using the ratio weighting of the downlink channel information of two BS that are calibrated.Then, this can be used to calculate the fuzzy factor between these two BS through weighting SRS.

Consider to comprise the TDD CoMP system that is connected to B base station of CPU (CU) via low time delay back haul link, it is called as centralized CoMP system.It should be appreciated by those skilled in the art, the proposed solution of present disclosure can be used in non-centralized CoMP system.Example is above only for illustrating.

In this example, each base station in this B base station is equipped with Nt antenna, and jointly serves M the subscriber equipment with single antenna.Modern indicate the downlink channel matrix of m UE, wherein be Nt n dimensional vector n, and indicate the downlink channel between b BS and m UE, α _mbsign comprises the decay on a large scale of path loss and shadow fading, sign comprises the channel vector of decline among a small circle.

So, according to formula (3) above, the relation between uplink channel and downlink channel can be expressed as:

$g_{\mathrm{mb}}^{\mathrm{UL}}={\mathrm{\Γ}}_b{g}_{\mathrm{mb}}^{\mathrm{DL}}---\left(4\right)$

Wherein indicate reciprocity error, and diag (x) expression has the diagonal matrix of the element of vector x.

The object of the antenna calibration between a plurality of BS is to obtain the ratio of the reciprocity error between different B S, and it can be defined as that is, the fuzzy factor between i BS and j BS.Then, this fuzzy factor can be used to adjust by the power of the signal being transmitted, to compensate the imbalance between the reciprocity error of each antenna in a plurality of BS.

According to the definition of the reciprocity error in formula (3), the fuzzy factor between i BS and j BS can be as follows by downlink channel and uplink channel direct representation between these two BS and UE.

${\mathrm{\λ}}_{\mathrm{ij}}=\frac{g_{\mathrm{mi},k}^{\mathrm{DL}}}{g_{\mathrm{mi},k}^{\mathrm{UL}}}/\frac{g_{\mathrm{mj},k}^{\mathrm{DL}}}{g_{\mathrm{mj},k}^{\mathrm{UL}}}=\frac{g_{\mathrm{mi},k}^{\mathrm{DL}}}{g_{\mathrm{mj},k}^{\mathrm{DL}}}\·\frac{g_{\mathrm{mj},k}^{\mathrm{UL}}}{g_{\mathrm{mi},k}^{\mathrm{UL}}}---\left(5\right)$

G wherein _{mi, k}indicate k antenna in i BS to the channel between m UE.

From equation (5), can find out that two fuzzy factors between BS can down link and uplink ratios based on these two BS and UE calculate.

Fig. 3 illustrates exemplary signal flow process according to an embodiment of the invention.In Fig. 3 in illustrated scene, our hypothesis at these two BS (that is, BSi and BSj) antenna in both by self calibration.In other words, each antenna in same BS is identical with the reciprocity error of UE.Therefore, in fact the calibration between two BS is equivalent to the calibration of an antenna in each BS.Simplicity, considers that each BS only has individual antenna for illustrative, and carries out calibration between B=2 base station (BSi and BSj).

Further, we suppose a centralized CoMP system, and the BS that wherein cooperates (for example, BSi310i and BSj310j) should be connected with CPU (CU) 330 by back haul link.Under such framework, each UE320 feeds back to its channel condition information (CSI) its this locality or serving BS broadcasts, and then CU collects CSI by back haul link from all BS.Utilization is at all users' at CU place CSI, and centralized CoMP system realizes the cooperation of global optimum between BS.Yet, it will be understood by those of skill in the art that the proposed solution of present disclosure for example can be used in, in non-centralized CoMP system (, Distributed C oMP system), and therefore communicating by letter and can correspondingly be adapted between BS and CU.

As shown in Figure 3, one or more UE320 are selected, to support or to assist the antenna calibration between a BSi310i and the 2nd BSj310j.These two BS all can communicate by letter with CU330.Without loss of generality, suppose that UE320 is served by BSj310j.Therefore, the link between UE320 and BSj310j can be called as link-local, and link between UE320 and BSi340i can be called as cross link.

At step S301 place, BSi and BSj for example, are transferred to UE320 by training sequence (, downlink reference signal (DL RS)).When receiving this training sequence, at step S303 place, UE320 can carry out estimating down-ward link channel state information (DL CSI) according to the RS receiving.Channel estimating can be implemented by various known technology, for example the MMSE of least squares error (LSE), least mean-square error (MMSE) and modification.

For example, based on MMSE, estimate, real downlink channel can be expressed as:

$g_{\mathrm{mb}}^{\mathrm{DL}}={\hat{g}}_{\mathrm{mb}}^{\mathrm{DL}}+n_{\mathrm{mb}}^{\mathrm{DL}},b=\mathrm{1,2},...,B---\left(6\right)$

Wherein indicate estimative downlink channel, and indicate noise.

Then, UE320 can calculate the ratio of these two DL CSI.Particularly, UE can calculate that the ratio of channel is as follows among a small circle by the down link of two BS that are calibrated:

$\begin{array}{c}\frac{{\hat{h}}_{\mathrm{mi}}^{\mathrm{DL}}}{{\hat{h}}_{\mathrm{mj}}^{\mathrm{DL}}}=\frac{h_{\mathrm{mi}}^{\mathrm{DL}}+n_{\mathrm{mi}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mi}}}}{h_{\mathrm{mj}}^{\mathrm{DL}}+n_{\mathrm{mj}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}=\frac{({\mathrm{\γ}}_i^{\mathrm{BS}}/{\mathrm{\γ}}_m^{\mathrm{UE}})h_{\mathrm{mi}}^{\mathrm{UL}}+n_{\mathrm{mi}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mi}}}}{({\mathrm{\γ}}_j^{\mathrm{BS}}/{\mathrm{\γ}}_m^{\mathrm{UE}})h_{\mathrm{mj}}^{\mathrm{UL}}+n_{\mathrm{mj}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}\\ =\frac{{\mathrm{\λ}}_{\mathrm{ij}}{h}_{\mathrm{mi}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\mathrm{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mi}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mi}}}}{h_{\mathrm{mj}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\mathrm{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mj}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}\end{array}---\left(7\right)$

Definition a wherein _ijand θ _ijindicate respectively amplitude and the phase place of the ratio of DL CSI.

Meanwhile, at step S302 place, UE320 is transferred to BS310i and 310j by uplink sounding reference signal (UL SRS, is denoted as sm).When receiving this UL SRS, at step S304 place, each BS in BS can carry out estimating uplink channel condition information (UL CSI) according to the SRS receiving.Similarly, based on for example MMSE, estimate, real uplink channel can be expressed as:

$g_{\mathrm{mb}}^{\mathrm{UL}}={\hat{g}}_{\mathrm{mb}}^{\mathrm{UL}}+n_{\mathrm{mb}}^{\mathrm{UL}},b=\mathrm{1,2},...,B---\left(8\right)$

Wherein indicate estimative uplink channel, and indicate noise.

In certain embodiments, estimative UL CSI can be transferred to CU330 via back haul link at step S305 place.

As calculated the ratio of DL CSI, at step S306 place, UE320 can be transferred to weighting SRS at least one BS in two BS in next up link image duration.

In certain embodiments, SRS can carry out weighting by amplitude and/or the phase place of the ratio of DL CSI.For example, consider that the signal being transmitted will be by power normalization, SRS can be only with phase place (that is, exp (the i θ of this ratio _ij) sm) carry out weighting.Generally speaking, weighting SRS can be expressed as A _ijexp (i θ _ij) sm.Such weighting will can not affect the orthogonality of the SRS between a plurality of UE.

For simplicity, UE320 can be broadcast to weighting SRS two BS that are calibrated, because SRS will be used for other functions except channel estimating by BS.

Afterwards, at step S307 place, BS (for example, service Bsj) can obtain by channel estimating:

${\hat{g}}_{\mathrm{mj}}^{\mathrm{UL}}=\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}\left(\frac{{\mathrm{\λ}}_{\mathrm{ij}}{h}_{\mathrm{mi}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\mathrm{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mi}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mi}}}}{h_{\mathrm{mj}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\mathrm{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mj}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}\right)h_{\mathrm{mj}}^{\mathrm{UL}}+z_i^{\mathrm{UL}}---\left(9\right)$

By simplifying formula (9) above, can obtain observation equation (10):

$\begin{array}{}\end{array}\begin{array}{c}{\hat{g}}_{\mathrm{mj}}^{\mathrm{UL}}=\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}\left(\frac{{\mathrm{\λ}}_{\mathrm{ij}}{h}_{\mathrm{mi}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\mathrm{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mi}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mi}}}}{h_{\mathrm{mj}}^{\mathrm{UL}}+({\mathrm{\γ}}_m^{\mathrm{UE}}/{\text{\γ}}_j^{\mathrm{BS}})n_{\mathrm{mj}}^{\mathrm{DL}}/\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}\right)(h_{\mathrm{mj}}^{\mathrm{UL}}+\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}\frac{n_{\mathrm{mj}}^{\mathrm{DL}}}{\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}}-\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}\frac{n_{\mathrm{mj}}^{\mathrm{DL}}}{\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}})+z_i^{\mathrm{UL}}\\ ={\mathrm{\λ}}_{\mathrm{ij}}\sqrt{{\mathrm{\α}}_{\mathrm{mj}}}{h}_{\mathrm{mi}}^{\mathrm{UL}}+\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mi}}^{\mathrm{DL}}+\frac{{\hat{h}}_{\mathrm{mi}}^{\mathrm{DL}}}{{\hat{h}}_{\mathrm{mj}}^{\mathrm{DL}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mj}}^{\mathrm{DL}}+z_i^{\mathrm{UL}}\\ ={\mathrm{\λ}}_{\mathrm{ij}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}({\hat{g}}_{\mathrm{mi}}^{\mathrm{UL}}+n_{\mathrm{mi}}^{\mathrm{UL}})+\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mi}}^{\mathrm{DL}}+\frac{{\hat{h}}_{\mathrm{mi}}^{\mathrm{DL}}}{{\hat{h}}_{\mathrm{mj}}^{\mathrm{DL}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mj}}^{\mathrm{DL}}+z_i^{\mathrm{UL}}\\ ={\mathrm{\λ}}_{\mathrm{ij}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}{\hat{g}}_{\mathrm{mi}}^{\mathrm{UL}}+{\mathrm{\λ}}_{\mathrm{ij}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}{n}_{\mathrm{mi}}^{\mathrm{UL}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}\frac{}{}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mi}}^{\mathrm{DL}}+\frac{{\hat{h}}_{\mathrm{mi}}^{\mathrm{DL}}}{{\hat{h}}_{\mathrm{mj}}^{\mathrm{DL}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mj}}^{\mathrm{DL}}+z_i^{\mathrm{UL}}\\ ={\mathrm{\λ}}_{\mathrm{ij}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}{\hat{g}}_{\mathrm{mi}}^{\mathrm{UL}}+w_{\mathrm{ij}}^m\end{array}---\left(10\right)$

Wherein $w_{\mathrm{ij}}^m={\mathrm{\λ}}_{\mathrm{ij}}\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}{n}_{\mathrm{mi}}^{\mathrm{UL}}+\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mi}}^{\mathrm{DL}}+\frac{{\hat{h}}_{\mathrm{mi}}^{\mathrm{DL}}}{{\hat{h}}_{\mathrm{mj}}^{\mathrm{DL}}}\frac{{\mathrm{\γ}}_m^{\mathrm{UE}}}{{\mathrm{\γ}}_j^{\mathrm{BS}}}{n}_{\mathrm{mj}}^{\mathrm{DL}}+z_i^{\mathrm{UL}}$ Indicate observation noise, and its variance can be expressed as:

$\mathrm{Var}\left(w_{\mathrm{ij}}^m\right)=\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}(\frac{{\mathrm{\α}}_{\mathrm{mi}}{\mathrm{\σ}}_{\mathrm{UL}}^2}{{\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{UL}}^2}+\frac{{\mathrm{\α}}_{\mathrm{mi}}{\mathrm{\σ}}_{\mathrm{DL}}^2}{{\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{DL}}^2})+\frac{{\mathrm{\α}}_{\mathrm{mi}}^2{\mathrm{\σ}}_{\mathrm{DL}}^2}{{\mathrm{\α}}_{\mathrm{mj}}({\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{DL}}^2)}+{\mathrm{\σ}}_{\mathrm{UL}}^2:={\mathrm{\ϵ}}_{m,\mathrm{ij}}^{\mathrm{Tra}}---\left(11\right)$

As seen from observation equation (10), at least the UL of the UL CSI based on i BS and j BS equivalence CSI, obtains the fuzzy factor λ between these two BS _ij.In other words, depend on λ _ijdefinition (that is, the reciprocity error ratio of cross link and link-local), for higher accuracy, λ _ijcan be calculated by the UL of the UL CSI based on cross link and link-local equivalence CSI.

Therefore, with Fig. 3, continue, at step S308 place, BS310i and 310j can be transferred to CU330 by estimative UL equivalence CSI.

Alternatively, the estimative UL CSI transmitting in step S305 can be transmitted in step S308 together with equivalent CSI.

Then, at step S309 place, obtained these UL CSI and UL equivalence CSI, CU can calculate fuzzy factor by the observation equation (10) based on above.A plurality of observation equatioies can be used to the jointly ambiguous estimation factor.

In one embodiment, a plurality of subscriber equipmenies can be selected to support calibration, and it can be called as multi-user's calibration.

In another embodiment, a plurality of uplink frame of unique user equipment can be used to support calibration, and it can be called as multiframe calibration.

In yet another embodiment, a plurality of uplink frame of a plurality of subscriber equipmenies can be used to support calibration, and it can be called as the calibration of multi-user's multiframe.

No matter adopt which kind of mode as above, can obtain a plurality of (for example, M) observation equation, they can be combined into:

y _Tra＝h _Traλ _ij+w _Tra (12)

Wherein $y_{\mathrm{Tra}}=\left[\begin{array}{c}{\hat{g}}_{1j}^{\mathrm{UL}}\\ \·\\ \·\\ \·\\ {\hat{g}}_{\mathrm{Mj}}^{\mathrm{UL}}\end{array}\right],$ $h_{\mathrm{Tra}}=\left[\begin{array}{c}\sqrt{\frac{{\mathrm{\α}}_{1j}}{{\mathrm{\α}}_{1i}}{\hat{g}}_{1i}^{\mathrm{UL}}}\\ \·\\ \·\\ \·\\ \sqrt{\frac{{\mathrm{\α}}_{\mathrm{Mj}}}{{\mathrm{\α}}_{\mathrm{Mi}}}}{\hat{g}}_{\mathrm{Mi}}^{\mathrm{UL}}\end{array}\right],$ And $w_{\mathrm{Tra}}=\left[\begin{array}{c}{w}_{\mathrm{ij}}^1\\ \·\\ \·\\ \·\\ w_{\mathrm{ij}}^M\end{array}\right].$

W _tracovariance be:

By using the parameter Estimation based on weighted least squares (WLS), fuzzy factor can be acquired as:

${\widehat{\mathrm{\λ}}}_{\mathrm{ij}}=\frac{h_{\mathrm{Tra}}^H{R}_{\mathrm{Tra}}^{-1}}{h_{\mathrm{TRa}}^H{R}_{\mathrm{Tra}}^{-1}{h}_{\mathrm{Tra}}}\·y_{\mathrm{Tra}}---\left(14\right),$

And evaluated error can be expressed as:

$\mathrm{Var}\left({\widehat{\mathrm{\λ}}}_{\mathrm{ij}}\right)={\left(h_{\mathrm{Tra}}^H{R}_{\mathrm{Tra}}^{-1}{h}_{\mathrm{Tra}}\right)}^{-1}={\left(\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{\mathrm{\α}}_{\mathrm{mj}}{\left|{\hat{h}}_{\mathrm{mi}}^{\mathrm{UL}}\right|}^2{\mathrm{\ϵ}}_{m,\mathrm{ij}}^{\mathrm{Tra}}\right)}^{-1}---\left(15\right).$

As seen from formula (15), the modulus of the fading channel among a small circle of evaluated error and UE relevant.Therefore, when adopting multi-user to calibrate, to add up independently; When adopting multiframe calibration, there is temporal correlation.If UE moves lentamente and channel in deep fading, the evaluated error of multiframe calibration will increase significantly.Significantly, obtain more statistics and independently observe equation, fuzzy factor can be estimated more exactly.

Further, according to observation equation (10), its SNR can be expressed as:

$\begin{array}{c}{\mathrm{SNR}}_m^{\mathrm{ob}}=\frac{E\left\{{\left|\sqrt{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}}{\hat{g}}_{\mathrm{mi}}^{\mathrm{UL}}\right|}^2\right\}}{E\left\{{\left|w_{\mathrm{ij}}\right|}^2\right\}}\\ =\frac{\frac{{\mathrm{\α}}_{\mathrm{mi}}{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{UL}}^2}}{\frac{{\mathrm{\α}}_{\mathrm{mj}}}{{\mathrm{\α}}_{\mathrm{mi}}}(\frac{{\mathrm{\α}}_{\mathrm{mi}}{\mathrm{\σ}}_{\mathrm{UL}}^2}{{\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{UL}}^2}+\frac{{\mathrm{\α}}_{\mathrm{mi}}{\mathrm{\σ}}_{\mathrm{DL}}^2}{{\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{DL}}^2})+\frac{{\mathrm{\α}}_{\mathrm{mi}}^2{\mathrm{\σ}}_{\mathrm{DL}}^2}{{\mathrm{\α}}_{\mathrm{mj}}({\mathrm{\α}}_{\mathrm{mi}}+{\mathrm{\σ}}_{\mathrm{DL}}^2)}+{\mathrm{\σ}}_{\mathrm{UL}}^2}\\ \stackrel{\left(a\right)}{\≈}{(\frac{1}{{\mathrm{SNR}}_{\mathrm{mi}}^{\mathrm{UL}}}+\frac{1}{{\mathrm{SNR}}_{\mathrm{mi}}^{\mathrm{DL}}}+\frac{{\mathrm{\α}}_{\mathrm{mi}}}{{\mathrm{\α}}_{\mathrm{mj}}}\frac{1}{{\mathrm{SNR}}_{\mathrm{mj}}^{\mathrm{DL}}}+\frac{1}{{\mathrm{SNR}}_{\mathrm{mj}}^{\mathrm{UL}}})}^{-1}\end{array}---\left(15\right)$

Its conditional (a) supposes that edge SNR is much larger than 1.Therefore, from formula (15), can see, up link SNR between UE and two BS and the harmonic average of down link SNR.Therefore, the minimum uplink SNR of cross link (that is, ) account for leading.In order to reduce observation error, the mode of full blast is the SNR that increases cross link.In other words, when selecting UE as holder for calibrating, the cell edge UE with the high SNR (that is, approaching real cell edge) of cross link should be selected for the calibration of assisting between a plurality of BS.In certain embodiments, selecteed holder UE be have higher than predetermined threshold, with by the edge UE of the SNR of the link of each BS in the BS being calibrated.

Those skilled in the art will appreciate that the parameter estimation algorithm that can also adopt other, such as least square (LS), the consistent LS of random sample (Ransac LS), least square intermediate value (LMedS) etc.

With Fig. 3, continue, obtained fuzzy factor, CU330 can be transferred to this fuzzy factor any or both in BS310i and 310j at step S310 place.Then at step S311 place, BSi and/or BSj can calibrate its antenna separately with the fuzzy factor receiving.

In certain embodiments, any BS in BS can be selected as reference, and then another BS can be calibrated based on this fuzzy factor.At some, in other embodiment, the lower BS of the gain of its RF chain can be selected as this reference.In a further embodiment, two BS all can be calibrated based on this fuzzy factor, and may need for distribute the algorithm of gain ratio between BS.

So, about Fig. 3, the mechanism of antenna calibration between two BS of proposing has been discussed.It will be apparent to one skilled in the art that two calibrations between BS can easily extend to more than two BS.Particularly, when exist 2 of B > by be calibrated base station time, i BS can be selected as reference.Calibration process is performed between a BS in i BS and remaining (B-1) individual BS at every turn.After calibration process (B-1) on carry out is inferior, all B BS is calibrated.It will be apparent to one skilled in the art that B-1 calibration can also be carried out simultaneously.

Utilize embodiments of the invention, antenna can be calibrated between a plurality of BS.Further, by the feedback via weighting SRS, by the feedback error quantizing or limit bit causes, can be eliminated and feedback overhead can be reduced.Therefore the fuzzy factor between a plurality of BS that, caused by self calibration can be calculated exactly and therefore antenna can accurately be calibrated.Proposed solution can be used in TDD CoMP system, does not make system performance degradation to recover channel reciprocity.

Emulation is performed, to assess the performance of antenna calibration according to an embodiment of the invention.Table I has been summed up general environment simulation parameter.

Table I: simulation parameter

Fig. 4 illustrates the comparison of the simulation result of various calibration stepss.

As shown in Figure 4, it shows the simulation result of following scheme: desirable calibration, via the calibration of training (, via the calibration that utilizes the weighting SRS of 30 UE), the only desirable calibration of phase place, utilize normalized pilot tone calibration (, calibration via phase weighting SRS), the calibration in non-CoMP (NC) and BS (that is, the self calibration of each BS).Trunnion axis represents the cell edge SNR of YidBWei unit, and vertical axis represents average every user rate.

As seen from Fig. 4, the gap between top line and bottom line is caused by the ambiguity between BS.Calibration via training is in close proximity to desirable calibration according to an embodiment of the invention; Utilize the calibration of normalized pilot tone to be in close proximity to the only ideal calibration of phase place.Therefore, the calibration steps of proposal this performance of can almost entirely regenerating.

In following description, will proposed mechanism be described in detail in detail about illustrated exemplary embodiment in accompanying drawing.

Fig. 5 illustrates the exemplary process diagram of method 500 according to an aspect of the present invention.Depend on the framework of TDD CoMP system (, centralized CoMP or non-centralized CoMP), method 500 can be by the base station cooperating in this CoMP system (for example, eNB) entity in is carried out, or carries out by being distributed in BS in this CoMP system and a plurality of entities among CU.Method 500 can be performed for boresight antenna between a plurality of BS.As an example, with reference to two BS as example (BS and the 2nd BS) and a holder UE, carry out discussion method 500.The 2nd BS is just serving UE, and the link between the 2nd BS and UE is link-local, and link between a BS and UE is cross link.

As shown in Figure 5, method 500 can start and proceed to step S502 at step S501 place.At step S502 place, if the BS being calibrated is comprised to a plurality of antennas, the plurality of antenna can be calibrated by self-calibration process.This self-calibration process can be carried out according to any technology known or further exploitation, such as hardware self calibration, feedback self calibration.The present invention is not restriction in this.

Then, at step S503 place, can (that is, SRS) obtain the uplink channel state information (UL CSI) of these two BS by the training sequence based on sending from UE.As described earlier, fuzzy factor λ _ijthe calculating UL equivalence CSI of the UL CSI based on cross link and link-local at least.Therefore,, at this step place of this example, only need to obtain the UL CSI of a BS.Yet the UL CSI of these two BS can be estimated for other objects.

Method 500 can proceed to step S504.At step S504 place, can the training sequence being weighted (that is, weighting SRS) based on sending from UE obtain the up link equivalence CSI of these two BS.Similarly, at the step S504 place of this example, only need to obtain the UL equivalence CSI of link-local or the 2nd BS.

As the step S303 with Fig. 3 describes together with S306, can carry out weighting SRS with the ratio of the down link CSI of the 2nd BS by the down link CSI with a BS (DL CSI), to obtain weighting SRS.In certain embodiments, SRS can be carried out weighting by the amplitude of the ratio with DL CSI and/or phase place.For example, consider that transmitted signal is by by power normalization, SRS can only carry out weighting by the phase place of this ratio.

Then, at step S505 place, obtained UL CSI and UL equivalence CSI, at least the UL of the UL CSI based on a BS and the 2nd BS equivalence CSI, calculates two fuzzy factors between BS.The UL equivalence CSI of UL CSI that can be based on a BS and the 2nd BS that obtains by a plurality of UE and/or in a plurality of image duration, combines and estimates this fuzzy factor.The calculating of fuzzy factor can be with reference to above about the description of the step S309 in Fig. 3, and therefore describe in detail be described in this and be omitted.

Afterwards, the fuzzy factor of calculating can be used to boresight antenna between these two BS.For example, a BS can be selected as reference, and the 2nd BS adjusts the gain of its RF chain when transmission based on fuzzy factor.

Fig. 6 illustrates the exemplary process diagram of method 600 according to another aspect of the present invention.The entity of method 600 in can the subscriber equipment in TDD CoMP system carried out.In order to illustrate, will use the scene identical with method 500 to carry out discussion method 600, that is, two BS (BS and the 2nd BS) and a holder UE are as example.The 2nd BS is just serving UE, and the link between the 2nd BS and UE is link-local, and link between a BS and UE is cross link.

As shown in Figure 6, method 600 can start and proceed to step S602 at step S601 place.At step S602 place, UE can be transferred to SRS by the BS being calibrated.On the other hand, at step S603 place, UE can be respectively from receiving pilot signal or reference signal (RS) by each BS the BS being calibrated.UE can estimate the DLCSI of these two BS and calculate the ratio of these two DL CSI.

Then, at step S604 place, UE can carry out its SRS of weighting with the ratio of these two DL CSI that calculate.In certain embodiments, SRS can carry out weighting by amplitude and/or the phase place of the ratio of DL CSI.

Finally, at step S605 place, at least one BS that UE just can be transferred to weighting SRS in these two BS in service UE.As mentioned previously, fuzzy factor λ _ijthe calculating UL equivalence CSI of the UL CSI based on cross link and link-local at least.Therefore, UE can only be transferred to weighting SRS the 2nd BS, i.e. its local BS.Preferably, UE can be broadcast to weighting SRS two BS, because SRS can be further used for other objects by these BS.

Therefore, via the SRS of the ratio weighting with DL CSI, UE can feed back DL CSI exactly, and it can be used to the ambiguous estimation factor.

In certain embodiments, a plurality of UE (for example, 30 or more) can be selected to support antenna calibration.Each UE in these UE can manner of execution 600 calibrate with auxiliary antenna.Those cell edges UE with the high SNR (that is, approaching real cell edge) of cross link can be selected for the calibration between auxiliary a plurality of BS.In other words, selecteed holder UE be have higher than predetermined threshold, with by the edge UE of the SNR of the link of each BS in the BS being calibrated.

At some, in other embodiment, a plurality of uplink frame of unique user equipment can be used to support calibration.If UE is just in fast moving, the performance of multiframe calibration may due to time the channel that becomes increase.UE can be in a plurality of image duration of repetition methods 600.

In a further embodiment, a plurality of uplink frame of a plurality of subscriber equipmenies can be used to support calibration.

Fig. 7 is the schematic block diagram that can be configured to the device 700 of implementation exemplary embodiment according to an aspect of the present invention.Device 700 can be merged in BS or eNB, and is configured to carry out the method for exemplary embodiment of the present invention.Alternatively, device 700 can be distributed among various network elements (such as BS and CU), to carry out the method for exemplary embodiment of the present invention.

As shown in Figure 7, device 700 can comprise acquiring unit 701 and computing unit 702.

Acquiring unit 701 can be configured to: the training sequence based on sending from UE obtains the UL CSI of a BS, and via the training sequence being weighted sending from this UE, obtains the UL equivalence CSI of the 2nd BS.Amplitude and/or the phase place of the ratio of the DL CSI by the DL CSI with a BS and the 2nd BS are carried out this training sequence of weighting, and obtain the training sequence of weighting.

Computing unit 702 can be configured to: the UL of the UL CSI based on a BS and the 2nd BS equivalence CSI at least, calculates the fuzzy factor between a BS and the 2nd BS.Then, the fuzzy factor of calculating can be used to boresight antenna between these two BS.

Computing unit 702 can further be configured to: the UL equivalence CSI of the UL CSI based on a BS and the 2nd BS that obtains by a plurality of UE and/or in a plurality of image duration, combines and estimates this fuzzy factor.

Should be appreciated that the unit 701-702 being included in device 700 is arranged to implementation exemplary embodiment of the present invention.Therefore, above with reference to Fig. 3 and 5 the operation described and feature, be also applied to device 700 and unit wherein, and they be described in detail in this and be omitted.

Fig. 8 is the schematic block diagram that can be configured to the device 800 of implementation exemplary embodiment according to another aspect of the present invention.Device 800 can be merged in UE, and is configured to carry out the method for exemplary embodiment of the present invention.

As shown in Figure 8, device 800 can comprise estimation unit 801, weighted units 802 and transmission unit 803.

Estimation unit 801 can be configured to estimate the DL CSI of at least two BS.The training sequence (RS) of this estimation based on sending from BS.

Weighted units 802 can be configured to, and with the ratio of the DL CSI of two BS, carrys out weighting SRS.The DL CSI of this ratio based on being estimated by estimation unit 801 calculates.

Transmission unit 803 can be configured to, and SRS or weighting SRS are transferred to the BS being calibrated.

Should be appreciated that the unit 801-803 being included in device 800 is arranged to implementation exemplary embodiment of the present invention.Therefore, operation and the features above with reference to Fig. 3 and 6, described are also applied to device 800 and unit wherein, and they be described in detail in this and be omitted.

Fig. 9 illustrates and is suitable for carrying out according to the simplified block diagram of the BS901 using in exemplary embodiment of the present invention and UE902.In Fig. 9, wireless network is adapted to communicating by letter via BS901 (being called as in the above example LTE-LAN BS (or eNB)) and UE902 (being called as in the above example LTE-LAN UE).Suitable RF reflector TX and receiver RX905 (it does not need to be embodied in same assembly) that UE902 comprises data processor (DP) 903, is coupled to the memory (MEM) 904 of DP903 and is coupled to DP903.MEM904 storage program (PROG) 906.TX/RX905 is used to the two-way wireless communication with BS901.Note, TX/RX905 has at least one antenna to promote communication; A plurality of antennas can be used the communication for multiple-input and multiple-output MIMO, and UE902 can have a plurality of TX and/or RX in this case.

Suitable RF reflector TX and receiver RX909 that BS901 comprises data processor (DP) 907, is coupled to the memory (MEM) 908 of DP907 and is coupled to DP907.MEM608 storage program (PROG) 910.TX/RX909 is used to the two-way wireless communication with UE902.Note, TX/RX909 has at least one antenna to promote communication, but BS will have several antennas conventionally in practice.BS901 may further include the communication interface 911 for docking with other network elements.Communication interface 911 can be for the X2 interface with other BS two-way communications.Alternatively or additionally, communication interface 911 can be the back haul link with CU.BS1100 can be coupled to one or more external networks or system via data path, such as for example internet.

BS901 can be coupled to one or more external networks or system via data path, such as for example internet.

At least one in PROG906 and 910 comprised following program command by hypothesis, when these program command are carried out by the DP903 being associated and 907, UE902 and BS901 can be operated according to the exemplary embodiment of the present invention of discussing together with method 500 or 600 as this paper.

Generally speaking, the various embodiment of UE902 can comprise, but be not limited to, cell phone, have wireless communication ability personal digital assistant (PDA), have wireless communication ability portable computer, have wireless communication ability image capture device (such as digital camera), have wireless communication ability game station, the music storage with wireless communication ability and playback device, portable unit or the terminal of the combination permitting wireless Internet access and the internet device of browsing and be incorporated to these functions.

Embodiments of the invention can be by implementing by the one or more computer softwares of carrying out in the DP903,907 of UE902 and BS901, or implement by hardware or by the combination of software and hardware.

MEM904 and 908 can be any type that is suitable for local technical environment, and can implement with any suitable data storage technology, as non-limiting example, such as memory devices, magnetic memory device and system, optical memory devices and system, read-only storage and the removable memory of based semiconductor.Although only a MEM is illustrated in BS901 or UE902, in BS901 or UE902, can there are several physically different memory cells.DP903 and 907 can be any type that is suitable for local technical environment, and as nonrestrictive example, can comprise: one or more in all-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP) and the processor based on polycaryon processor framework.Any in UE902 and BS901 or both can have a plurality of processors, such as for example, are subject in time making the dedicated IC chip of the synchronous clock control of primary processor.

Above the illustrated block diagram of reference method, device (that is, system) and flow chart description exemplary embodiment of the present invention.To understand, each piece of block diagram and flowchart illustrations, and the combination of the piece of block diagram and flowchart illustrations, can be implemented by the various devices that comprise computer program instructions respectively.These computer program instructions can be loaded on all-purpose computer, special-purpose computer or other programmable data processing unit to produce a kind of machine, make these instructions of carrying out on this computer or other programmable data processing unit create the device for implementing procedure segment or a plurality of specified functions.

Aforementioned computer program instructions can be for example subroutine and/or function.Computer program in one embodiment of the present of invention comprises at least one computer-readable recording medium, and aforesaid computer program instructions is stored on this computer-readable recording medium.Computer-readable recording medium can be, for example, and light compact disk or as the electronic memory device of RAM (random access storage device) or ROM (read-only memory).

Although this specification comprises many concrete implementation details; but these implementation details should not be interpreted as the scope of any execution mode or the restriction to scope that may be claimed, but be interpreted as being specific to the description of feature of the specific embodiment of specific implementations.The enforcement that can also be combined in single embodiment of some feature of describing in the context of separated embodiment in this manual.Otherwise the various features of describing in the context of single embodiment can also be implemented discretely or with any suitable sub-portfolio in a plurality of embodiment.In addition; although may describe feature as above with some combinations; and even at first by so claimed; but; one or more features in claimed combination can be removed in some cases from this combination, and combination required for protection can directed sub-portfolio or the distortion of sub-portfolio.

Should also be noted that, embodiment described above provides in order to describe the present invention rather than restriction the present invention, and will understand, as the skilled person easily understood, without departing from the spirit and scope of the present invention in the situation that, can be by modifications and variations.Such modifications and variations are considered in the scope in the present invention and claims.Protection scope of the present invention is limited to the appended claims.In addition, any reference number in the reference number in claim should not be interpreted as limitations on claims.Verb " comprises " and those elements or the element step or the existence of step of stating in claim do not got rid of in paradigmatic use.Indefinite article before element or step " one " or " one " do not get rid of the existence of a plurality of such elements or step.

Claims (18)

1. for a method for boresight antenna between the first base station (BS) and the 2nd BS, comprising:

Training sequence based on sending from subscriber equipment obtains the uplink traffic channel information of a described BS;

Via the training sequence being weighted sending from described subscriber equipment, obtain the up link equivalent channels information of described the 2nd BS, wherein the ratio of the downlink channel information by the downlink channel information with a described BS and described the 2nd BS comes described in weighting training sequence to obtain the described training sequence being weighted; And

The described up link equivalent channels information of the described uplink traffic channel information based on a described BS and described the 2nd BS at least, calculate the fuzzy factor between a described BS and described the 2nd BS, wherein said fuzzy factor is used to calibrate the antenna at least one BS in a described BS and described the 2nd BS.

2. method according to claim 1, at least one BS in a wherein said BS and described the 2nd BS comprises a plurality of antennas, and described a plurality of antenna is calibrated by self-calibration process.

3. method according to claim 1 and 2, wherein calculating fuzzy factor comprises: based on by a plurality of subscriber equipmenies and/or in the described uplink traffic channel information of a described BS and the described up link equivalent channels information of described the 2nd BS that be acquired a plurality of image duration, combine and estimate described fuzzy factor.

4. method according to claim 1 and 2, wherein said subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and a link described BS and described two BS higher than predetermined threshold.

5. method according to claim 1 and 2, wherein described in weighting, training sequence comprises: by the amplitude of the described ratio of the downlink channel information of a described BS and the downlink channel information of described the 2nd BS and/or phase place, carry out training sequence described in weighting.

6. for subscriber equipment, assist a method for two antenna calibrations between base station, comprising:

Training sequence is transferred to described two base stations;

Estimate the downlink channel information of described two base stations;

With the ratio of the described downlink channel information of described two base stations, carry out training sequence described in weighting; And

The training sequence being weighted is transferred to at least one base station of just serving described subscriber equipment in described two base stations.

7. method according to claim 6, described subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and links described two base stations higher than predetermined threshold.

8. according to the method described in claim 6 or 7, wherein said subscriber equipment repeats described estimation, weighted sum transmission in a plurality of image duration.

9. according to the method described in claim 6 or 7, the training sequence of wherein said estimation based on sending from described two base stations.

10. for a device for boresight antenna between the first base station (BS) and the 2nd BS, comprising:

Acquiring unit, be configured to the uplink traffic channel information that training sequence based on sending from subscriber equipment obtains a described BS, and via the training sequence being weighted sending from described subscriber equipment, obtain the up link equivalent channels information of described the 2nd BS, wherein the ratio of the downlink channel information by the downlink channel information with a described BS and described the 2nd BS comes described in weighting training sequence to obtain the described training sequence being weighted; And

Computing unit, be configured at least described up link equivalent channels information of the described uplink traffic channel information based on a described BS and described the 2nd BS, calculate the fuzzy factor between a described BS and described the 2nd BS, wherein said fuzzy factor is used to calibrate the antenna at least one BS in a described BS and described the 2nd BS.

11. devices according to claim 10, at least one BS in a wherein said BS and described the 2nd BS comprises a plurality of antennas, and described a plurality of antenna is calibrated by self-calibration process.

12. according to the device described in claim 10 or 11, wherein said computing unit is further configured to: based on by a plurality of subscriber equipmenies and/or in the described uplink traffic channel information of a described BS and the described up link equivalent channels information of described the 2nd BS that obtain a plurality of image duration, combine and estimate described fuzzy factor.

13. according to the device described in claim 10 or 11, and wherein said subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and a link described BS and described two BS higher than predetermined threshold.

14. according to the device described in claim 10 or 11, and the described training sequence being wherein weighted is carried out weighting by amplitude and/or the phase place of the described ratio of the downlink channel information of the downlink channel information with a described BS and described the 2nd BS.

15. 1 kinds of devices of assisting two antenna calibrations between base station for subscriber equipment, comprising:

Transmission unit, is configured to training sequence to be transferred to described two base stations;

Estimation unit, is configured to estimate the downlink channel information of described two base stations; And

Weighted units, is configured to ratio with the described downlink channel information of described two base stations and carrys out training sequence described in weighting;

Wherein said transmission unit is further configured to the training sequence being weighted to be transferred at least one base station of just serving described subscriber equipment in described two base stations.

16. devices according to claim 15, described subscriber equipment is the edge customer equipment with the signal to noise ratio (SNR) of and links described two base stations higher than predetermined threshold.

17. according to the device described in claim 15 or 16, and wherein said subscriber equipment repeats described estimation, weighted sum transmission in a plurality of image duration.

18. according to the device described in claim 15 or 16, and the training sequence that wherein said estimation unit is configured to based on sending from described two base stations is estimated described downlink channel information.