CN102958124A - Method and device for switching user equipment into second cell from first cell - Google Patents

Abstract

The invention discloses a method and a device for switching user equipment into a second cell base station from a first cell base station. The method comprises the steps of: setting a specific range extension offset value aiming at the user equipment; judging whether the underwent signal to interference ratio is not smaller than a first threshold after the user equipment is switched into the second cell base station from the first cell base station; judging whether the sum of power of a reference mark which is received from the second cell base station and measured by the user equipment and the specific range extension offset value aiming at the user equipment is greater than the power of the reference mark which is received from the first cell base station and measured by the user equipment, and switching the user equipment into the second cell base station from the first cell base station under the situation that the judgment result is positive. According to the method and the device, effective ICIC (inter-cell interference coordination) can be achieved, and huge or even insufferable spending is not generated.

Description

Subscriber equipment is switched to the method and apparatus of the second residential quarter from the first residential quarter

Technical field

The present invention relates to the communications field, more specifically, the present invention relates to a subscriber equipment is switched to from the first cell base station the method and apparatus of the second cell base station.

Background technology

When having disposed a plurality of Microcell that can openly access in macrocell, some subscriber equipmenies can be served by Microcell, thereby alleviate the burden of macrocell, realize load balance.Wherein macrocell for example is basic wireless cellular network residential quarter among LTE-A, 3G, the GSM, and Microcell is such as being pico residential quarter, femto residential quarter etc.

In the LTE-A system, base station (eNB) can send reference symbol, and be mutually orthogonal between the reference symbol that wherein each base station sends.Each subscriber equipment can be measured the power of the reference symbol that receives from its base station on every side.And, if subscriber equipment is in connection mode, the reference symbol received power of measuring can be reported to its serving BS.

For any user equipment (UE) _j, use

Represent the set of its peripheral base station, if UE _jBe in connection mode, and when considering to switch,

Also comprise U E _jServing BS.And, use RSRP _IjExpression UE _jThe power of the reference symbol that receives from base station i of measuring, the so conventional cell association criterion based on the reference symbol received power of measuring can be expressed as follows:

$\mathrm{Cell}\_{\mathrm{ID}}_{\mathrm{serving}}=\arg {\max }_{\left\{i\right\}}\left\{{\mathrm{RSRP}}_{\mathrm{ij}}\right\},i\∈{\mathrm{\Λ}}_{\mathrm{surr}}^{\left(j\right)}---\left(1\right)$

The implication of above-mentioned criterion is UE _jProminent that base station of the reference symbol that receives from its peripheral base station of its measurement will be associated with.

In the situation of macrocell-picocell deployment, if still use such as given cell association criterion in (1), than Microcell, will have more subscriber equipment to be associated with macrocell so, reason is that the transmitted power of macro cell base station is much larger than the transmitted power of microcell base station.In this case, the available resources of Microcell are not fully utilized, and in macrocell, very fierce for the competition meeting of available resources.For the potential load balance function that is provided by Microcell more effectively is provided, for the deployment scenario of macrocell-Microcell, for any UE _j, use following cell association criterion:

$\mathrm{Cell}\_{\mathrm{ID}}_{\mathrm{serving}}=\arg {\max }_{\left\{i\right\}}\{{\mathrm{RSRP}}_{\mathrm{ij}}+{\mathrm{bias}}_i\},i\∈{\mathrm{\Λ}}_{\mathrm{surr}}^{\left(j\right)}---\left(2\right)$

The implication of above-mentioned criterion is UE _jThe power of the reference symbol that receives from its peripheral base station of its measurement and the bias (bias of peripheral base station will be associated with _i) with that base station (macro cell base station or microcell base station) of maximum.

In above-mentioned equation (2), for macrocell, bias is 0, and for each Microcell, bias is a nonnegative value, thereby more subscriber equipment can be arranged by the Microcell service.Because the use of bias is equivalent to give the ability of the scope of Microcell extending user device association, so this process is called the scope expansion (RE) of Microcell, and above-mentioned bias also is called scope expansion bias.

For system, need to correctly design Microcell scope expansion bias, realizing good load balance, and do not cause additionally owing to disturbing the problem that produces, the subscriber equipment of the Microcell that the scope that for example is associated with is expanded is experiencing low signal interference ratio (SIR).

Current, in LTE version-10 (Rel-10), recommend in the specific mode in residential quarter scope expansion bias to be set.And, consider the simplicity of realization, in LTE Rel-10, recommend for all Microcells of disposing in the macrocell, identical scope expansion bias is set.

Based on a large amount of assessment reports, can draw following conclusion:

Situation for the scope expansion of not supporting Microcell, for descending (DL) control channel (CCH), there is not problem of inter-cell interference, and for the DL data channel, presence of intercell interference cancellation (ICIC) scheme of reusing Rel-8/9 just can solve problem of inter-cell interference well.

Yet, for the specific scope expansion bias setting in use residential quarter and for each Microcell, use the situation of the current standard recommendation of identical scope expansion bias, observe increase scope expansion bias and can realize better load balance, but can make the lower SIR of subscriber equipment experience that is associated with corresponding Microcell, particularly for the subscriber equipment that is in the Microcell edge, the risk that therefore can cause DL CCH problem of inter-cell interference to occur increases, and finally causes radio jink failure.

Propose a kind of time division multiplexing (TDM) ICIC technology, be called almost blank subframe (ABS) technology, solved DL CCH problem of inter-cell interference.In the ABS technology, macro cell base station as interference source, be configured to the subframe of ABS at some, in physics DLCCH (PDCCH), do not carry out transfer of data, and only transmit the specific reference symbol in residential quarter (CRS) and possibly, at other primary channel, for example carry out transfer of data on the Physical Broadcast Channel.Obviously, in being configured to the subframe of ABS, do not carry out transfer of data at Physical Downlink Shared Channel (PDSCH), namely do not carry out transfer of data at data channel.In the implementation procedure of ABS technology, the interfere information of time domain must be via the communication link between certain base station, and for example the back haul link of X2-type exchanges between neighbor cell.

Yet the ABS technology still suffers the interference problem of " CRS is to control signal ", even reason is that macro cell base station should keep transmitting CRS in blank subframe almost.More importantly, the inherent shortcoming of this TDM ICIC technology is to have reduced time-domain resource available in the macrocell, thereby causes the throughput performance of subscriber equipment in the macrocell to reduce.

Therefore, importantly be or for the plan of establishment of the scope of current consideration expansion bias, design more effective DL CCH ICIC technology, or the plan of establishment of the scope of design improvement expansion bias, the load balance that it can be realized, and can realize good DL CCH ICIC effect.

Summary of the invention

According to an aspect of the present invention, proposed a kind of a subscriber equipment to be switched to the method for the second cell base station from the first cell base station, comprised step: arrange for the specific scope expansion of this subscriber equipment bias; Judge when described subscriber equipment after described the first cell base station switches to described the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from described the second cell base station of judging that described subscriber equipment measures and the reference symbol that receives from described the first cell base station of whether measuring greater than described subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And under the result of above-mentioned judgement is sure situation, described subscriber equipment is switched to described the second cell base station from described the first cell base station.

According to another aspect of the present invention, proposed a kind of a subscriber equipment to be switched to the device of the second cell base station from the first cell base station, comprising: setting unit is used for arranging for the specific scope expansion of this subscriber equipment bias; Judging unit, be used for to judge when described subscriber equipment after described the first cell base station switches to described the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from described the second cell base station of judging that described subscriber equipment measures and the reference symbol that receives from described the first cell base station of whether measuring greater than described subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And switch unit, be used for judged result at above-mentioned judging unit and be in the sure situation described subscriber equipment being switched to described the second cell base station from described the first cell base station.

According to the present invention, can realize effective ICIC, not have huge or even not endurable expense.

Description of drawings

By below in conjunction with the description of the drawings, and along with understanding more comprehensively of the present invention, other purposes of the present invention and effect will become more clear and easy to understand, wherein:

Fig. 1 shows the environment 100 that the present invention can realize therein;

Fig. 2 shows the flow chart according to the method for the second cell base station that a subscriber equipment is switched to from the first cell base station of an embodiment of the invention;

Fig. 3 shows the block diagram that a subscriber equipment is switched to the device of the second cell base station from the first cell base station according to an embodiment of the invention.

In all above-mentioned accompanying drawings, identical label represents to have identical, similar or corresponding feature or function.

Embodiment

In execution mode as described below of the present invention, pay close attention to for the specific scope expansion of subscriber equipment bias scheme.According to the embodiment of the present invention, can realize effective ICIC, and not have huge or even not endurable expense.

Fig. 1 shows the environment 100 that the present invention can implement therein.

As shown in Figure 1, this environment 100 comprises the base station 110 corresponding to residential quarter 111, corresponding to base station 120 and a plurality of subscriber equipment 130-1,130-2,130-3,130-4,130-5 and the 130-6 of residential quarter 112.

Base station 110 provides coverage 110-a, and base station 120 provides coverage 120-a.

Subscriber equipment can be in environment 100 interior movements, and can enter or withdraw from coverage 110-a and 120-a.Therefore, subscriber equipment communicates by Radio Link 140 and base station 110.Perhaps, subscriber equipment communicates by Radio Link 150 and base station 120.In addition, communicate by back haul link 160 between base station 110 and the base station 120.Back haul link 160 can be wired, also can be wireless.

Here, suppose that base station 110 is macro cell base station, base station 120 is microcell base stations, and wherein macro cell base station is such as being basic wireless cellular network base station among LTE-A, 3G, the GSM etc., and microcell base station for example is that pico base station, femto base station, via node or remote radio frequency are first-class.In description of the invention, base station and residential quarter are to concern one to one.Namely a residential quarter only has a base station, and a residential quarter is only served in a base station.

As shown in Figure 1, coverage 110-a comprises coverage 120-a fully.Certainly, those skilled in the art will appreciate that coverage 110-a can partly comprise coverage 120-a.Even coverage 110-a and coverage 120-a do not intersect.

Here, for simplicity and for the purpose of clear, in Fig. 1, only show a Microcell and 6 subscriber equipmenies, it will be understood by those of skill in the art that number that the present invention is applicable to be deployed with in the macrocell a plurality of Microcells and subscriber equipment is greater or less than 6 scene.

More generally, use Be illustrated in and be associated with the second cell base station before switching, namely microcell base station k (k ∈ 1 ..., the number of current user equipment K}).With

Be illustrated in to switch and be associated with the first cell base station, the namely number of the current user equipment MUE of macro cell base station before.

Before switching, be associated with the subscriber equipment MUE of macro cell base station for any one _j, measure from the power of the reference symbol of its peripheral base station (comprising macro cell base station and microcell base station) reception.

At subscriber equipment MUE _jMaximum that is expressed as the power of the reference symbol that microcell base station around it of measuring receives

[dBm], the wattmeter of the reference symbol that receives from other K-1 microcell base stations is shown

(l=1 ..., K-1) [dBm].In addition, for MUE _j, the wattmeter of the reference symbol that receives from its macro cell base station of its measurement is shown

[dBm].

For outstanding basic thought of the present invention, ignore in the following description the impact of noise.

After carrying out the RSRP measurement, this MUE _jWill be to its serving BS, namely macro cell base station is reported the RSRP and corresponding cell identifier ID of its measurement.

In the following description, mainly pay close attention to the switching of subscriber equipment from the macro cell base station to the microcell base station, that is to say, in the following description, the first cell base station refers to macro cell base station; The second cell base station refers to microcell base station.

Certainly, it will be understood by those of skill in the art that basic principle of the present invention also is applicable to the switching of subscriber equipment from the microcell base station to the microcell base station.

Therefore, the first cell base station in claims both can refer to macro cell base station, also can refer to microcell base station.

In addition, in the following description, mainly pay close attention to from macro cell base station to the switching that causes that microcell base station of maximum reference symbol received power at subscriber equipment.

For any one given MUE _j, use

${\mathrm{SIR}}_{\mathrm{ifbeco}\min \mathrm{gPUE}}^{\left(j\right)}=Y_{P,0}^{\left(j\right)}-Y_M^{\left(j\right)}-{\mathrm{\Σ}}_{l=1~K-1}{Y}_{P,l}^{\left(j\right)}\left[\mathrm{dB}\right]$

This MUE of expression supposition _jSwitch to generation from macro cell base station Microcell base station, become the subscriber equipment of this microcell base station, namely after the PUE, the descending signal interference ratio of estimation.For the switching in the connection mode, this parameter by the macro cell base station utilization from MUE _jThe report each corresponding base station (comprising macro cell base station and microcell base station) RSRP and estimate to obtain.

Fig. 2 shows the flow chart according to the method for the second cell base station that a subscriber equipment is switched to from the first cell base station of an embodiment of the invention.

Method 200 comprises step S205, arranges for the specific scope expansion of this subscriber equipment bias; Step S210, judge when subscriber equipment after the first cell base station switches to the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from the second cell base station of judging that subscriber equipment measures and the reference symbol that receives from the first cell base station of whether measuring greater than subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And

Step S220 under the result of above-mentioned judgement is sure situation, switches to the second cell base station with subscriber equipment from the first cell base station.

Wherein, in an embodiment of the invention, first threshold is the target signal interference ratio SIR of down control channel _{CCH target}

Certainly, those skilled in the art will appreciate that first threshold also can be other values.For example, in yet another embodiment of the present invention, first threshold is the maximum in the minimum value of target signal interference ratio of the target signal interference ratio of down control channel and downstream data channel, and namely first threshold is

Wherein the latter is the minimum value of the target signal interference ratio of downstream data channel.

Wherein, as mentioned above, the second cell base station is except macro cell base station, causes that microcell base station of maximum reference symbol received power at the subscriber equipment place.

Said method 200 is for example carried out by macro cell base station.

From MUE _jObtain after the RSRP measured value of each base station, whether macro cell base station will detect following inequality 3 and 4 and set up:

${\mathrm{SIR}}_{\mathrm{ifbeco}\min \mathrm{gPUE}}^{\left(j\right)}\≥{\mathrm{SIR}}_{\mathrm{CCHt}\arg \mathrm{et}}---\left(3\right)$

$Y_{P,0}^{\left(j\right)}+{\mathrm{\β}}_j>Y_M^{\left(j\right)}$ (that is, $Y_{P,0}^{\left(j\right)}-Y_M^{\left(j\right)}>-{\mathrm{\β}}_j$ )(4)

SIR wherein _{CCH target}Be the target signal interference ratio of down control channel, β _j[dB] represents MUE _jUser equipment (UE) particular range expansion bias, wherein β _jIt is a nonnegative value.

If inequality 3 and 4 is set up, macro cell base station will contact with this microcell base station so, to switch, with MUE _jSwitch to microcell base station from macro cell base station.

If

Be false, that is to say, if

Set up, clearly, in this case, MUE _jShould remain and be associated with under the macro cell base station, should not switch to microcell base station.

If

Set up, from the viewpoint of ICIC, via switching MUE _jBecome to be associated with under the microcell base station and be fine.

UE particular range expansion RE bias β is discussed now _jDesign.

Below, if will

Set up this information slip and be shown situation 1; If will

Set up this information slip and be shown situation 2.

If situation 1 time, from the viewpoint of ICIC, via switching MUE _jBecome be associated with under the microcell base station cannot, therefore do not need to design β _j

Situation 2 is divided into two kinds of subcases: situation 2.1 and situation 2.2.

If wherein

Belong to so situation 2.1; If Belong to so situation 2.2.

Situation 2.1 times, according in the traditional cell association standard based on RSRP shown in the equation 1, even in the expansion of not execution of microcell level scope, also be to recommend MUE _jBy being switching to PUE.When the correlation rule shown in the use inequality 4, no matter nonnegative value β _jWhy setting is worth, for example, and with β _jBe set to 0, thereby in fact do not support RE, inequality 4 also always can be set up, thus MUE _jWill be by being switching to PUE.

At the macro cell base station place, based on the RSRP measurement report of current acquisition, the number of determining to satisfy the MUE of situation 2.1 is n (n is non-negative).This n MUE will become PUE by switching, and no matter what value of their the specific RE bias of UE setting.That is to say, n is associated with in the current user equipment of the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from the first cell base station.

More specifically, this n MUE will switch to different microcell base stations, because for two different MUE among this n MUE, the microcell base station that produces the RSRP of maximum measurement might be different.

Use n _k(n _k〉=0) expression falls into situation 2.1, and after switching will by microcell base station k (k ∈ 1 ..., the number of the MUE that K}) serves.That is to say, for n _kAmong the individual MUE each, microcell base station k is the base station that produces maximum RSRP.

Obviously, ∑ _K=1～Kn _k=n.

Situation 2.2 times, for MUE _j, whether can be transformed to by means of RE PUE and will mainly rely on β _jSpecial setting.

For the MUE that drops in the case _j, remain MUE and become PUE by switching and will produce different impacts to the system load balance, and therefore throughput performance is had different impacts.

Next, will provide first the relevant analysis of some throughputs, then utilize the relevant analysis of throughput, carry out β _jDesign.

In macro cell base station, based on the current RSRP measurement report that obtains, the number of determining the MUE of the situation that falls into 2.2 is m (m 〉=0).That is to say, m is associated with in the current user equipment of the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is not more than the number of subscriber equipment of the power of the reference symbol that receives from the first cell base station.Each of this m MUE depends on the specific RE bias of the UE that arranges respectively for them, perhaps remains MUE or by being switching to PUE.

Use m _k(m _k〉=0) if expression drop on situation 2.2 and to its RE bias be arranged so that switch to occur will by microcell base station k (k ∈ 1 ..., the number of the MUE that K}) serves.That is to say, for this m _kAmong the individual MUE each, microcell base station k is the microcell base station that causes maximum RSRP.Obvious ∑ _K=1～Km _k=m.

Use SIR ^(j)[dB] represents MUE _jThe descending SIR that experienced before switching, this descending SIR is by MUE _jEstimate, and report to macro cell base station.

If MUE _jMight become the PUE that is served by microcell base station k, i.e. this MUE by switching _jThe m of previous definition _kIndividual MUE (m wherein _k〉=0) in one is as this MUE of supposition _jRemain MUE, so this MUE _jMinimum and maximum possible throughput can be estimated as respectively as follows:

$C_{M,\min }^{\left(j\right)}=\frac{B}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}\·{\log }_2(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})---\left(5.1\right)$

$C_{M,\max }^{\left(j\right)}=\frac{B}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n-(m-1)}\·{\log }_2(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})---\left(5.2\right)$

Shown in (5.1)

Corresponding to following scene, in this scene, drop on all m MUE in the situation 2.2 all still by the macro cell base station service.

Shown in (5.2)

Corresponding to following scene, drop among all m MUE in the situation 2.2, only have this MUE _jRemain by the macro cell base station service

In (5.1) and (5.2), deduct n and be because drop on n MUE in the situation 2.1 their the specific RE bias of UE is set howsoever, all will become PUE by switching.

If MUE _jMight become the PUE that is served by microcell base station k, i.e. this MUE by switching _jThe m of previous definition _kIndividual MUE (m wherein _k〉=0) in one is as this MUE of supposition _jWhen being switching to PUE, its throughput minimum and maximum possible can be estimated as respectively as follows:

$C_{P,\min }^{\left(j\right)}=\frac{B}{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+m_k}\·{\log }_2(1+{10}^{(Y_{P,0}^{\left(j\right)}-Y_M^{\left(j\right)})/10})---\left(6.1\right)$

$C_{P,\max }^{\left(j\right)}=\frac{B}{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}\·{\log }_2(1+{10}^{(Y_{P,0}^{\left(j\right)}-Y_M^{\left(j\right)})/10})---\left(6.2\right)$

Wherein shown in (6.1)

Corresponding to following scene, in this scene, all m _kIndividual MUE passes through to switch and becomes PUE.

(6.2)

Corresponding to following scene, in this scene, m _kOnly has this MUE among the individual MUE _jBecome PUE by switching.In (6.1) and (6.2), add n _kBecause of the n that drops in the situation 2.1 _kIndividual MUE will become the PUE by microcell base station k service, no matter why the specific RE bias of UE that arranges for them is worth.

As shown in the technical report of a lot of 3GPP standards, for any one given UE total number Z, the increase of the number of the PUE that causes along with RE, all UE throughput sums or in all UE, come the throughput (Z=100 for example of that UE of the x% reciprocal * Z in its throughput, x%=5%, total exactly 100 UE in throughput come the throughput of the reciprocal the 5th poor that UE) can increase first, then after the number of the PUE that RE causes meets or exceeds a certain particular value, the continuation of the number of the PUE that causes along with RE increases, all UE throughput sums, the throughput that perhaps comes that UE of the x% reciprocal * Z in all UE in its throughput can reduce.

Therefore, in the time need to carrying out MUE to the switching of PUE by means of RE, wise way is only just to switch when this switching is useful to throughput performance.

For situation 2.2, only under the help of RE, MUE _jJust can switch to microcell base station, in an embodiment of the invention, propose the specific RE bias of the following UE plan of establishment (it does not need any support of the RRC signaling of air interface):

For any one MUE among m the MUE that belongs in the situation of dropping on 2.2 _j, only have and work as

The time, just can be by switching this MUE _jBecome PUE.

For MUE _jIf, microcell base station k (k ∈ 1 ..., be to produce maximum RSRP K})

Corresponding microcell base station, by mathematical derivation,

Be equal to

$Y_{P,0}^{\left(j\right)}-Y_M^{\left(j\right)}>10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+m_k}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n-(m-1)}}-1)---\left(7\right)$

More specifically, for situation 2.2 (wherein

), the necessary condition that inequality (7) will be set up is that the right side of inequality (7) should be a negative value.

Therefore, for situation 2.2,, can be summarized as follows at the switching condition shown in the inequality (7) and in the rule of the cell association shown in the inequality (4) by relatively:

When the right side in the inequality (7) less than 0 the time, with in the inequality (4)-β _jBe set to the value on right side in the inequality (7).If inequality (4) establishment, so corresponding MUE _jWill be by being switching to PUE.

The right side is more than or equal to 0 in inequality (7), thereby for situation 2.2,

Forever be not being met, although still can with in the inequality (4)-β _jBe set to the value on right side in the inequality (7), thereby inequality (4) is untenable, and MUE _jRemain MUE.Yet, because β _jUsually be set to a nonnegative value (namely-β _jLess than or equal to 0), for this situation, can be simply with β _jBe set to 0dB, thereby for situation 2.2, inequality (4) is untenable.

Therefore, according to an embodiment of the invention, for MUE _jSpecific scope expansion bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)---\left(8\right)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.---\left(9\right)$

If inequality (3) and inequality (4) can be set up, macro cell base station will be communicated by letter with switching the target microcell base station so, to realize MUE _jSwitching, thereby this MUE _jBecome PUE.If (3) or (4) untenable, this MUE so _jRemain by the macro cell base station service.

Attention: if inequality (3) can be set up MUE so _jTo become the n of previous definition _k(n _k〉=0) among the individual MUE, or become the m of previous definition _k(m _k〉=0) among the individual MUE.

Particularly, if MUE _jThe n of previous definition _k(n _k〉=0) (if the MUE namely of among the individual MUE _jTo drop in the situation 2.1), so no matter how the RE value arranges this MUE _jAll will become the PUE by microcell base station k service.As front to as described in the situation 2.1, to this situation,

So, although λ _jBe to design for the cell association that drops on the MUE in the situation 2.2, but for situation 2.1, the cell association rule of describing in inequality (4) still can work; Because according to (8) and (9), ε λ _jTo always be non-negative, the MUE that therefore drops in the situation 2.1 always can be switching to the PUE that is served by microcell base station k.

Except microcell base station k (k ∈ 1 ..., the number of current PUE K})

Every other parameter in inequality (3) and (4) can both obtain in macro cell base station, and does not need the minizone signaling.Particularly, macro cell base station can by the macro cell base station of X2 type and the back haul link between the microcell base station, obtain parameter

Based on a large amount of simulation results of reporting in the 3GPP standard, for the average DLSIR at MUE place, " well " magnitude is approximately or is better than 12dB that " poor " magnitude is approximately or is worse than 5dB.

Next, for to λ _jValue have one to get information about, use SIR ^(j)=5dB, 10dB, 15dB or 20dB as an example, when

When value changes, to λ _jValue carry out following Numerical evaluation.

If SIR ^(j)=5dB: when

1/6 or 1/8 o'clock, λ _j≈ 3.68dB, 5.71dB or 7.10dB;

If SIR ^(j)=10dB: when 1/6 or 1/8 o'clock, λ _j≈ 0.85dB, 3.09dB or 4.57dB;

If SIR ^(j)=15dB: when

1/6 or 1/8 o'clock, λ _j≈-1.43dB, 1.04dB or 2.63dB;

If SIR ^(j)=20dB: when

1/6, or 1/8 o'clock, λ _j≈-3.36dB ,-0.64dB or 1.08dB.

In fact, when the deployment of microcell base station is laxer, can use more greedy switching criterion.That is to say, for any one MUE among m the MUE that belongs in the situation of dropping on 2.2 _j, can work as

The time, by switching this MUE _jBecome PUE.

In this case, by mathematical derivation, can draw

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)---\left(10\right)$

Therefore, according to an embodiment of the invention, for the specific scope expansion of this subscriber equipment bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)---\left(10\right)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.---\left(9\right)$

Fig. 3 shows the block diagram that a subscriber equipment is switched to the device of the second cell base station from the first cell base station according to an embodiment of the invention.

As shown in Figure 3, this device 300 comprises setting unit 305, is used for arranging for the specific scope expansion of this subscriber equipment bias; Judging unit 310, be used for to judge when subscriber equipment after the first cell base station switches to the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from the second cell base station of judging that subscriber equipment measures and the reference symbol that receives from the first cell base station of whether measuring greater than subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And switch unit 320, be used for judged result at above-mentioned judging unit 310 and be in the sure situation subscriber equipment being switched to described the second cell base station from the first cell base station.

In an embodiment of the invention, first threshold is the target signal interference ratio of down control channel.

In another execution mode of the present invention, first threshold is the maximum in the minimum value of target signal interference ratio of the target signal interference ratio of down control channel and downstream data channel.

In an embodiment of the invention, the second cell base station is except the first cell base station, causes that cell base station of maximum reference symbol received power at the subscriber equipment place.

In an embodiment of the invention, for the specific scope expansion of this subscriber equipment bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+m_k}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n-(m-1)}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.,$

SIR wherein ^(j)The descending signal interference ratio of being experienced when the expression subscriber equipment was served by the first cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of the second cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of the first cell base station before switching;

N is associated with in the current user equipment of the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from the first cell base station;

M is associated with in the current user equipment of the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is not more than the number of subscriber equipment of the power of the reference symbol that receives from the first cell base station;

n _kIn the expression said n subscriber equipment, the switching target small area base station is the number of the subscriber equipment of the second cell base station;

m _kRepresent that in the above-mentioned m subscriber equipment, the switching target small area base station is the number of the subscriber equipment of the second cell base station.

In an embodiment of the invention, for the specific scope expansion of this subscriber equipment bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.$

Wherein the switching target small area base station is except the first cell base station, causes that cell base station of maximum reference symbol received power at the subscriber equipment place.

Should be noted that for the present invention is more readily understood top description has been omitted to be known for a person skilled in the art and may to be essential more specifically some ins and outs for realization of the present invention.

Those skilled in the art it is also understood that and the invention is not restricted to step described above, and the present invention also comprises combination that step described above is carried out, order conversion etc.Final scope of the present invention is defined by the appended claims.

Therefore; selecting and describing execution mode is in order to explain better principle of the present invention and practical application thereof; and those of ordinary skills are understood, under the prerequisite that does not break away from essence of the present invention, all modifications and change all fall within protection scope of the present invention defined by the claims.

In addition, the step that those skilled in the art will appreciate that above-described the whole bag of tricks can realize by the computer of programming.Here, some execution mode is intended to the overlay program storage device, and it is machine or computer-readable, and coding has machine can carry out or the computer executable instructions program, and the some or all of steps of said method are carried out in wherein said instruction.This program storage device can be for example Disk and tape, hard disk drive or optical readable digital data storage medium of magnetic recording medium for example.Execution mode also is intended to cover the computer that is programmed for the described step of carrying out said method.

Claims (14)

1. one kind switches to the method for the second cell base station with a subscriber equipment from the first cell base station, comprises step:

Setting is for the specific scope expansion of this subscriber equipment bias;

Judge when described subscriber equipment after described the first cell base station switches to described the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from described the second cell base station of judging that described subscriber equipment measures and the reference symbol that receives from described the first cell base station of whether measuring greater than described subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And

Under the result of above-mentioned judgement is sure situation, described subscriber equipment is switched to described the second cell base station from described the first cell base station.

2. method according to claim 1, wherein said first threshold is the target signal interference ratio of down control channel.

3. method according to claim 1, wherein said first threshold are the maximum in the minimum value of target signal interference ratio of the target signal interference ratio of down control channel and downstream data channel.

4. method according to claim 1, wherein said the second cell base station is except described the first cell base station, causes that cell base station of maximum reference symbol received power at described subscriber equipment place.

5. method according to claim 1 is wherein expanded bias β for the specific scope of this subscriber equipment _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+m_k}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n-(m-1)}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.,$

SIR wherein ^(j)The descending signal interference ratio that experiences when representing described user device association to described the first cell base station;

Be illustrated in the number that is associated with the current user equipment of described the second cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of described the first cell base station before switching;

N is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

M is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is not more than the number of subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

Nk represents that in the said n subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station;

Mk represents that in the above-mentioned m subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station.

6. method according to claim 1 is wherein expanded bias β for the specific scope of this subscriber equipment _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.$

SIR wherein ^(j)The descending signal interference ratio that experiences when representing described user device association to described the first cell base station;

Be illustrated in the number that is associated with the current user equipment of described the second cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of described the first cell base station before switching;

N is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

n _kIn the expression said n subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station.

7. according to claim 5 or 6 described methods, wherein said switching target small area base station is except described the first cell base station, causes that cell base station of maximum reference symbol received power at described subscriber equipment place.

8. one kind switches to the device of the second cell base station with a subscriber equipment from the first cell base station, comprising:

Setting unit is used for arranging for the specific scope expansion of this subscriber equipment bias;

Judging unit, be used for to judge when described subscriber equipment after described the first cell base station switches to described the second cell base station, whether its signal interference ratio that experiences is not less than first threshold, and the power of the power of the reference symbol that receives from described the second cell base station of judging that described subscriber equipment measures and the reference symbol that receives from described the first cell base station of whether measuring greater than described subscriber equipment for the specific scope expansion of this subscriber equipment bias sum; And

Switch unit is used for judged result at above-mentioned judging unit and is in the sure situation described subscriber equipment being switched to described the second cell base station from described the first cell base station.

9. device according to claim 8, wherein said first threshold is the target signal interference ratio of down control channel.

10. device according to claim 8, wherein said first threshold are the maximum in the minimum value of target signal interference ratio of the target signal interference ratio of down control channel and downstream data channel.

11. device according to claim 8, wherein said the second cell base station are except described the first cell base station, cause that cell base station of maximum reference symbol received power at described subscriber equipment place.

12. device according to claim 8 is wherein for the specific scope expansion of this subscriber equipment bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+m_k}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n-(m-1)}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.,$

SIRJ wherein ^(j)The descending signal interference ratio that experiences when representing described user device association to described the first cell base station;

Be illustrated in the number that is associated with the current user equipment of described the second cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of described the first cell base station before switching;

N is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

M is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is not more than the number of subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

n _kIn the expression said n subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station;

m _kRepresent that in the above-mentioned m subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station.

13. device according to claim 8 is wherein for the specific scope expansion of this subscriber equipment bias β _jBe set to ε λ _j:

Wherein

${\mathrm{\λ}}_j=-10\·{\log }_{10}({(1+{10}^{{\mathrm{SIR}}^{\left(j\right)}/10})}^{\frac{N_{\mathrm{PUE},k}^{\left(\mathrm{curr}\right)}+n_k+1}{N_{\mathrm{MUE}}^{\left(\mathrm{curr}\right)}-n}}-1)$

$\mathrm{\ϵ}=\left\{\begin{array}{c}0,{\mathrm{\λ}}_j\≤0\\ 1,{\mathrm{\λ}}_j>0\end{array}\right.$

SIR wherein ^(j)The descending signal interference ratio that experiences when representing described user device association to described the first cell base station;

Be illustrated in the number that is associated with the current user equipment of described the second cell base station before switching;

Be illustrated in the number that is associated with the current user equipment of described the first cell base station before switching;

N is associated with in the current user equipment of described the first cell base station before being illustrated in and switching, if suppose that switching to this situation in switching target small area base station from described the first cell base station occurs, its signal interference ratio that experiences is not less than first threshold, and the power of the reference symbol that receives from the switching target small area base station is greater than the number of the subscriber equipment of the power of the reference symbol that receives from described the first cell base station;

n _kIn the expression said n subscriber equipment, the switching target small area base station is the number of the subscriber equipment of described the second cell base station.

14. according to claim 12 or 13 described devices, wherein said switching target small area base station is except described the first cell base station, causes that cell base station of maximum reference symbol received power at described subscriber equipment place.

Images