CN105722148B - Method in the heterogeneous network of lte-a system for avoiding invalid load balancing - Google Patents
Method in the heterogeneous network of lte-a system for avoiding invalid load balancing Download PDFInfo
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Abstract
The present invention relates to the method in the user equipment of the heterogeneous network of lte-a system for avoiding invalid load balancing, all micro-base stations in heterogeneous network will open RE extended capability.This method comprises: the RSRP based on user equipment and micro-base station adds the sum of RE extension bias and the RSRP between user equipment and macro base station to obtain transient service cell index；If it is macro base station or to generate the index of the base station of maximum RSRP at user equipment, serving BS is determined it as；Otherwise, serving BS is determined according to the Signal to Interference plus Noise Ratio level of estimation and the relationship of predetermined threshold, wherein if the former is more than or equal to the latter, which is determined as serving BS；Then judge whether to only include a micro-base station if it is less than the latter；If it is its serving BS is determined according to the size of its RSRP between each base station；Otherwise the step of rejecting the transient service cell index and then re-executing this method.Method according to the present invention can not use existing eICIC technology.
Description
Technical field
The present invention relates to wireless communication techniques, and in particular, to a kind of for being used to keep away in the heterogeneous network of lte-a system
Exempt from the method for invalid load balancing.
Background technique
Additional demand in terms of in order to meet in Cellular Networks, LTE-A network service capacity and/or coverage area, energy
Enough cells (such as Microcell) that low-power is disposed among macrocell.It is formed by network and is commonly referred to as heterogeneous network
(HetNet:heterogeneous network).Specifically, the Microcell (also referred to as micro-base station PeNB) of multiple open visits
When being deployed among the coverage area of macrocell (also referred to as macro base station MeNB), some user equipmenies (UE) then can be by multiple micro-
Cell services, to reach the benefit of load balancing.
Among lte-a system, when base station sends reference symbol (for different base stations mutually orthogonal), each
User equipment can measure the power from surrounding base station (including its serving BS) received reference symbol.Also, it is any one
The reference symbol that a user equipment can be measured receives power (RSRP:reference symbol received
Power) its serving BS is given in report.For any one user equipment (UE)j, useIndicate the cell index of its peripheral base station
Set.Also, use RSRPijIndicate UEjThe power from the received reference symbol of base station i of measurement, then conventional based on survey
The cell association criterion that the reference symbol of amount receives power can be expressed as follows:
And in the case where macro Microcell is total to channel deployment, if cell association criterion still as formula (1) gives,
Compared to Microcell, there will be more user equipmenies to be associated with macrocell, this is because the transmission power ratio of Microcell is macro small
The transimission power in area is much smaller.In this case, the available resources of Microcell are not fully utilized, and macro small
Qu Zhong, can be very fierce for the competition of available resources.It is potentially loaded as provided by Microcell to more efficiently utilize
Equalization function, for any one user equipment (UE)jFor, cell association standard (2) below will be proposed to be used in macro small
Area is total to the heterogeneous network of channel deployment:
Cell_IDserving=arg max{i}{RSRPij+ε·biasi} (2)
Wherein,And ε=0 when i is macrocell index, and ε=1 when i belongs to Microcell index.
In above formula (2), when i belongs to Microcell index, bias biasiFor a nonnegative value, to make
There must be more user equipmenies that can be serviced by Microcell.Microcell extending user is given since the use of bias is equivalent to
The ability of the associated range of equipment, therefore this process is referred to as the coverage extension (RE:range of Microcell
Extension), above-mentioned bias is also referred to as coverage extension bias.
Currently, in LTE version -10 (Rel-10), recommendation is arranged in a manner of cell specific (cell-specific)
Coverage extension bias.Also, in view of the simplicity realized, in LTE Rel-10, recommend for all small
Area is respectively provided with identical coverage extension bias, as shown in following formula (3):
Cell_IDserving=arg max{i}{RSRRPij+ ε bias } (3),
Wherein,And ε=0 when i is macrocell index, and ε=1 when i belongs to Microcell index.
Based on 3GPP a large amount of assessment reports done in relevant standardization effort, it can be deduced that following conclusion:
(1) the case where coverage extension is not done for Microcell, for down control channel, it is dry that there is no minizones
Problem is disturbed, and for downstream data channel, reuses the inter-cell interference cancellation (ICIC) in LTE version -8 or 9 (Rel-8/9)
Technology can well solve problem of inter-cell interference.
(2) however, being observed by 3GPP in the situation for the coverage extension bias scheme currently recommended for using
More user equipmenies can be allowed to be serviced by corresponding Microcell although increasing coverage extension bias, it is macro at this time small
Interference between area and corresponding Microcell can make the user equipment for being associated with corresponding Microcell undergo lower Signal to Interference plus Noise Ratio (especially
It is for the user equipment in corresponding small area edge) so that the user for being associated with corresponding Microcell sets
The probability of the raw down control channel transmission failure of preparation is increased.In addition, when coverage extension bias is larger, this by
Will be very serious the problem of down control channel caused by inter-cell interference, and the ICIC technology in LTE Rel-8/9 is simultaneously
The problem of inter-cell interference of the down control channel cannot be efficiently solved.Further, since good control channel performance
It is the prerequisite of data channel Successful transmissions, so if the problem of inter-cell interference of the down control channel cannot obtain
To very good solution, then the performance of data channel will be seriously affected.
In other words, in the coverage extension bias scheme currently recommended, model is covered by Microcell using by 3GPP
Enclose extension caused by respective load equilibrium may as present on down control channel inter-cell interference and become invalid.
Specifically, if coverage extension bias set by Microcell is bigger, then caused by being extended as picocell coverage area
The ratio of inactive loads equilibrium will be higher.
In order to solve the problem of inter-cell interference of above-mentioned down control channel, it has been proposed that many is " enhanced small
(eICIC:enhanced ICIC) is eliminated in section interference " technical solution.These eICIC technical solutions can generally be divided into two
Kind, respectively resource orthogonalization splitting scheme and power adjustment scheme.
The basic thought of resource orthogonalization splitting scheme be will be used for the radio resource of down control channel in macro base station and
It is orthogonally distributed between micro-base station, to reduce mutual interference as far as possible.Including time division multiplexing and frequency division multiplexing
Two kinds of technology.
Since the signal transmitted on down control channel will be transmitted on entire frequency band, so frequency division is multiple
Technical solution is not suitable for the problem of inter-cell interference for being used to solve above-mentioned down control channel.
Time-multiplexed technical solution mainly includes almost blank subframe (ABS:Almost Blank Subframe) technology
(time shifting) technology is translated with time domain.
In by the ABS technical solution of 3GPP standardization institute's keypoint recommendation, as the macro base station of interference source, in certain configurations
At the subframe of ABS, does not carry out data transmission on Physical Downlink Control Channel (PDCCH), only transmit cell specific reference signal
Baseband signals such as (CRS:Cell-specific Reference Signal).Obviously, in the subframe for being configured to ABS, not
Have and carry out data transmission on Physical Downlink Shared Channel (PDSCH), i.e., does not carry out data transmission on a data channel.This
Outside, during the realization of ABS technology, the interference of time domain letter packet must via the communication link between certain base station, such as based on
The backhaul link of X2 interface, swaps between neighboring community.However, ABS technology still suffers from " CRS is to control signal "
Interference problem, the reason is that even if transmission CRS is still required in macro cell base station in almost blank subframe.More importantly, this
The inherent shortcoming of time division multiplexing ICIC technology is reduction of available time-domain resource in macrocell, so as to cause user in macrocell
The throughput performance of equipment reduces；It is that it is eliminated using ABS on a control channel if there is multiple Microcells need macro base station
Inter-cell interference, this problem will be protruded extremely.In addition, when this time-division multiplex technology of ABS is applied to frequency division duplex (FDD) system
When system, a bit reduction is not had to the strict requirements of time synchronization, this will bring no small difficulty in realization.
In addition, time domain translation (time shifting) technology is similarly all in the presence of that cannot completely eliminate inter-cell interference etc.
More disadvantages.
Power adjustment scheme includes: the reduction emission of downlink control channel power at the macro base station as interference source, and
The increasing of emission of downlink control channel power is carried out to the user equipment for being located at corresponding small area edge at disturbed micro-base station
By force.But since the former can reduce the effective coverage range of macrocell and may cause covering dead angle, and the latter may mistake
More consumption power resources and user's scheduling gains that corresponding Microcell can be reduced, so in the deployment of actual commercial network,
It is not recommended that being used.
In summary, it would be desirable to consider that the coverage extension bias scheme for designing a kind of enhancing is invalid for avoiding
By the load balancing caused by coverage extension, while the program will not also have the shortcomings that existing eICIC technical solution.
Summary of the invention
According to it is above-mentioned to background technique and understanding, the invention proposes in lte-a system
Method in heterogeneous network for avoiding invalid load balancing, this method are not intended to how to optimize existing eICIC technical side
Case, but optimize coverage extension biasing technique scheme when establishing the incidence relation of user equipment and cell to realization pair
The ingenious performance evaded and optimize whole system in turn of inter-cell interference.
It is used to avoid invalid load balancing in the user equipment of the heterogeneous network of lte-a system described according to the present invention
Method, wherein the heterogeneous network includes that at least one macro base station, at least one micro-base station and at least one described user set
Standby, at least one described micro-base station will open coverage extension ability, the described method comprises the following steps:
A. the user equipment is based on the reference between the user equipment and at least one described micro-base station calculated
Symbol receives power plus the sum of coverage extension bias gained set by corresponding micro-base station and is calculated described
Reference symbol between user equipment and at least one described macro base station receives power to obtain the interim clothes of the user equipment
Business cell index；
B. if transient service cell index be a macro base station at least one described macro base station index or
The index that maximum reference symbol receives the base station of power is generated in all macro base stations and micro-base station at the user equipment, then
First base station with the transient service cell index is determined as to the serving BS of the user equipment；
C. otherwise, the base station with the transient service cell index must be micro-base station and the interim cell
It also must be caused by coverage extension is done in corresponding Microcell to the incidence relation of user equipment, then basis is faced by described at this time
When serving cell index determined by the user equipment the horizontal relationship between predetermined threshold of Signal to Interference plus Noise Ratio to determine
State the serving BS of user equipment, wherein the step (C) further comprises:
C1: if the Signal to Interference plus Noise Ratio level is more than or equal to the predetermined threshold, there will be the transient service
The first base station of cell index is determined as the serving BS of the user equipment；
C2: if the Signal to Interference plus Noise Ratio level is less than the predetermined threshold, judge whether only include one in all base stations
A micro-base station；
If only including a micro-base station in all base stations, the user equipment directly according to the user equipment with
Reference symbol between each base station receives the size of power to determine its serving BS；
If including being greater than or equal to two micro-base stations, the cell rope from all base stations in all base stations
The step of rejecting the transient service cell index in the set drawn, then re-executing the method.
Among one embodiment according to the present invention, at least one described micro-base station be arranged different bias or
Identical bias.Those skilled in the art it is to be appreciated that the scheme based on coverage extension can be arranged it is identical or
The different bias of person, the bias determine as the case may be.
Among one embodiment according to the present invention, when being that at least one described micro-base station is provided with identical bias
When, (C2) simplifies the step of the method are as follows:
If the Signal to Interference plus Noise Ratio level is less than the predetermined threshold, the user equipment is directly set according to the user
The standby reference symbol between each base station receives the size of power to determine its serving BS.
Among one embodiment according to the present invention, the load balancing is the coverage extension institute by Microcell
It realizes, and the invalid load balancing refers to the user equipment that allows caused by the coverage extension by Microcell
It can make the downlink control channel of the user equipment that there is unacceptable letter by the result that the first micro-base station is serviced
It is dry to make an uproar than level.
Among one embodiment according to the present invention, the predetermined threshold is that the target letter of downlink control channel is dry
It makes an uproar than or for the target Signal to Interference plus Noise Ratio of the downlink control channel and the target Signal to Interference plus Noise Ratio of down-link data channel
In biggish one, wherein the target Signal to Interference plus Noise Ratio of the down-link data channel can be used for down-link data channel
All alternative Modulation and Coding Scheme grades corresponding to minimum value in down-link data channel target Signal to Interference plus Noise Ratio.
Among one embodiment according to the present invention, when the user equipment is in connection mode and is currently by one
A macro base station is servicing, when the user equipment consider from the macro base station currently serviced for the user equipment be switched to by
Another base station services, if the method will terminate afterwards executing the step (C1) according to the present invention, at this time in step
Suddenly the resulting Signal to Interference plus Noise Ratio level of estimation used in (C1) is referred to as the first Signal to Interference plus Noise Ratio level, and the mesh switched at this time
Mark base station one is set to a micro-base station.
Among one embodiment according to the present invention, the first Signal to Interference plus Noise Ratio level can be comprised in be worked as by described
The preceding switching request that the micro-base station as handover-target base station is sent to for the macro base station that the user equipment is serviced
Among message, so that the micro-base station as handover-target base station can assist it according to the first Signal to Interference plus Noise Ratio level
For whether receiving the switching request and making decision, and assist it after determining to receive the switching request will to switch
The interface-free resources that will use are made planning by the user equipment to come over.This point it is not mandatory that, but it is optional.?
That is the first Signal to Interference plus Noise Ratio level both can be contained in by the current macro base station hair serviced for user equipment
Among the switching request message for giving the micro-base station as handover-target base station, it can not also be comprised in by described current
The switching request for being sent to the micro-base station as handover-target base station for the macro base station that the user equipment is serviced disappears
Among breath.Even if the first Signal to Interference plus Noise Ratio level is not comprised in by the macro base currently serviced for the user equipment
Station is sent among the switching request message of the micro-base station as handover-target base station, micro- base as handover-target base station
Stand also can for whether receive switching request make decision and determine receive the switching request after will switch
The interface-free resources that will use are made planning by user equipment.But when the first Signal to Interference plus Noise Ratio level is comprised in by described current
For the macro base station that user equipment is serviced be sent to the micro-base station as handover-target base station switching request message it
When middle, the micro-base station as handover-target base station can be according to the first Signal to Interference plus Noise Ratio level come for whether receiving described cut
It changes request and makes more reasonable decision, and the user equipment after decision receives the switching request for that will switch will
The interface-free resources used make more reasonable planning.
If using by 3GPP in the coverage extension bias scheme currently recommended, must be with existing one kind
It eICIC technical solution (such as 3GPP recommended ABS technical solution) while using, downlink control could be solved to a certain extent
The problem of inter-cell interference of channel processed, and can also make the bad of the shortcomings that system performance is by existing eICIC technical solution
Influence, for example, using caused by ABS technical solution to the reduction of time domain communication resource utilization and still can remaining CRS to control
The interference etc. of channel processed.
But if using enhancing proposed by the invention coverage extension bias scheme, it is any without using
A kind of existing eICIC technical solution, because the inter-cell interference of down control channel is in enhancing proposed by the invention
Coverage extension bias scheme among dexterously advised (namely when establishing the incidence relation of user equipment and cell)
It keeps away.Specifically, it among method according to the present invention, is just realized by micro- when meeting certain Signal to Interference plus Noise Ratio level requirement
User equipment caused by the coverage extension of cell is associated with corresponding Microcell, and is being unsatisfactory for above-mentioned Signal to Interference plus Noise Ratio water
It puts down and then realizes traditional cell association for receiving power (RSRP) based on reference symbol when requiring, to efficiently solve
The problem of inter-cell interference for the down control channel stated.
In addition, when the coverage extension bias to Microcell is set, since bias can neither be too big (too
Conference causes excessively serious interference) can not it is too small (it is too small, be not achieved through coverage extension and realize load balancing
Purpose), in the standardization effort of current 3GPP, determined using experiment simulation based on empirical appropriate
Bias.But such bias determined by experiment simulation is all that the network environment that is based on experiment simulation is close
It is relevant, and network environment is diversified in the deployment of actual network, it is difficult to ensure that being based on some specific network
Environment, which carries out bias determined by experiment simulation, can be suitable for various network environments；Meanwhile for each allusion quotation
The network environment of type all goes to carry out experiment simulation, and workload will be huge (even unpractical).
If it is imitative not need to carry out any experiment using the coverage extension bias scheme of enhancing proposed by the invention
Very, only need simply by bias be set as a biggish value can (be set as here it is larger rather than it is smaller be because
It is exactly to be contrary to very much this if being set as lesser value to realize load balancing to do the purpose of coverage extension to Microcell
Purpose).Because the inter-cell interference of down control channel (is namely establishing use among scheme proposed by the invention
When the incidence relation of family equipment and cell) dexterously evaded, there is no need to worry to be covered in the presence of invalid by Microcell
Load balancing caused by range extension.Even for certain specific network environments, set bias is excessive, so that
The overwhelming majority can be extended originally by picocell coverage area and bring load balancing finally will not all occur (because it will be
It is invalid to be therefore described by the present invention scheme and evaded), base station can in time be determined by the assessment to load balancing effect
It is fixed that the size of bias is adjusted.
Detailed description of the invention
The following detailed description to non-limiting embodiment, other spies of the invention are read by referring to accompanying drawing
Sign, objects and advantages will become more apparent upon.
Fig. 1 shows the flow chart 100 of method according to the present invention.
Run through different diagrams in the figure, same or similar appended drawing reference indicates the same or similar device (module)
Or step.
Specific embodiment
In the following detailed description of the preferred embodiment, reference is constituted to the appended attached drawing of present invention a part.Institute
Attached attached drawing, which has been illustrated by way of example, can be realized specific embodiment.Exemplary embodiment is not intended to
Exhaustive all embodiments according to the present invention.It is appreciated that without departing from the scope of the present invention, can use other
Embodiment can also carry out the modification of structure or logic.Therefore, it is below specific descriptions and it is unrestricted, and this
The range of invention is defined by the claims appended hereto.
Fig. 1 shows the flow chart 100 of method according to the present invention.As can be seen from the figure: described according to the present invention
For avoiding the method 100 of invalid load balancing in the heterogeneous network of lte-a system, wherein heterogeneous network includes at least one
Macro base station, at least one micro-base station and at least one user equipment, at least one micro-base station will open coverage extension energy
Power, method includes the following steps:
Firstly, in step 110, user equipment is based on the ginseng between the user equipment calculated and at least one micro-base station
It examines symbol and receives power plus the sum of coverage extension bias gained set by corresponding micro-base station and the use calculated
Reference symbol between family equipment and at least one macro base station receives power to obtain the transient service cell index of user equipment；
Specifically, such as by the index of macrocell be identified as { 0 }, and by the cell index set identification of Microcell be 1,
2,3,4 ..., K } (it is assumed that there is K micro-base station around the user equipment).Cell index is the corresponding base station of k at any one
Reference symbol caused by user equipment with user index j receives power and is denoted as Xkj, unit is watt, wherein k belongs to
In 0,1,2,3,4 ..., K in any one.Among one embodiment according to the present invention, at least one is micro- for described in
Different bias or identical bias is arranged in base station.Those skilled in the art based on coverage area it is to be appreciated that expanded
Same or different bias can be arranged in the scheme of exhibition, which determines as the case may be.
Specifically, in step 110, when setting different coverage extension bias for different Microcells,
The transient service cell index of user equipment j is determined by the following formula:
Wherein, ΩcurrFor the set of alternative transient service cell index, initial value is set to Ωcurr=0,1,
2,3,4,...,K}.In above-mentioned formula (4), when k is that macrocell indexes, ε=0 (will not do coverage area for macrocell
Extension), and when k belongs to Microcell index, ε=1.
Next, in the step 120, if transient service cell index is one at least one described macro base station macro
The index of base station or generating maximum reference symbol at the user equipment in all macro base stations and micro-base station receives function
First base station with transient service cell index is then determined as the service base of the user equipment by the index of the base station of rate
It stands.
Specifically, if Cell_IDScrving, tmp=0 or Cell_IDServing, tmp=arg max{ k=0,1 ..., K }
{Xkj, then it is Cell_ID by cell indexServing, tmpFirst base station be determined as the serving BS of user equipment j, at this time should
Method also just finishes.
Otherwise, in following step 130, the base station with the transient service cell index must be micro-base station,
And interim " incidence relation of cell and user equipment " also must be to do coverage extension by corresponding Microcell
It is caused, at this time then according to the Signal to Interference plus Noise Ratio of the user equipment determined by transient service cell index level and predetermined threshold
Between relationship determine the serving BS of the user equipment.
Specifically, for receiving end, that is, user equipment of downlink, P is usednoiseIndicate additive white Gaussian noise
(AWGN) mean power, unit are watt.PnoiseIt can be calculated using the following formula: Pnoise=Pnoise per Hz×
Working bandwidth × noise figure, wherein Pnoise perHz=10-174[dBm]/10×10-3(unit is watt),
Working bandwidth indicates bandwidth of operation, is given system parameter, and noise figure indicates noise coefficient,
It is respectively 10 for ITU channel model or 3GPP SCM channel model7[dB]/10Or 109[dB]/10.For simplification
For the sake of, the mean power of the additive white Gaussian noise at different user equipmenies uniformly uses parameter PnoiseIt is identified.With
SINRCCH target[dB] indicates the target Signal to Interference plus Noise Ratio of downlink control channel realization Successful transmissions in lte-a system,
For the system parameter with given value.
Step 130 further includes steps of
In summary, in sub-step 132, if the user equipment determined by the transient service cell index
Signal to Interference plus Noise Ratio level be more than or equal to predetermined threshold, then the first base station with transient service cell index is determined as institute
State the serving BS of user equipment；
Specifically, if Cell_IDServing, tmp≠ 0 and Cell_IDScrving, tmp≠arg max{ k=0,1 ..., K }{Xkj,
Then cell index is Cell_IDScrving, tmpBase station must be micro-base station, and described interim " index is Cell_
IDScrving, tmpCell and user equipment j incidence relation " also must be by cell index be Cell_DServing, tmpIt is small
Caused by coverage extension is done in area, SINR is set by the predetermined threshold of Signal to Interference plus Noise Ratio level at this timeCCH target, then judge with
Whether lower formula (5) is true:
Wherein i=Cell_IDServing, tmp。
It is Cell_D by cell index at this time if formula (5) is set upServing, tmpFirst base station be determined as user and set
The serving BS of standby j, this method also just finishes at this time.
On the contrary, if above equation (5) is invalid, that is to say, that in sub-step 134, if by the interim clothes
The Signal to Interference plus Noise Ratio level of the user equipment determined by cell index of being engaged in is less than predetermined threshold, then judge in all base stations whether
Only include a micro-base station；
If only including a micro-base station in all base stations, the user equipment directly according to the user equipment with
Reference symbol between each base station receives the size of power to determine its serving BS.It specifically, is arg by cell index
max{ k=0,1 ..., K }{XkjBase station be determined as the serving BS of user equipment j, this method also just finishes at this time；
If including being greater than or equal to two micro-base stations in all base stations, from the set of the cell index of all base stations
Middle rejecting transient service cell index, the step of then re-executing the method.Specifically, Ω is updatedcurrFor Ωcurr=
Ωcurr-Cell_IDSecring, tmP, the step of being then return to step 110, re-execute the method.
Among one embodiment according to the present invention, when being that at least one described micro-base station is provided with identical covering model
When enclosing extension bias, the step 134 of the method simplifies are as follows:
If the Signal to Interference plus Noise Ratio level of the user equipment determined by the transient service cell index is less than described
Predetermined threshold, then the user equipment directly receives power according to the reference symbol between the user equipment and each base station
Size determines its serving BS.It specifically, is arg max by cell index{ k=0,1 ..., K }{XkjBase station be determined as user
The serving BS of equipment j, this method also just finishes at this time.
Among one embodiment according to the present invention, the predetermined threshold of the Signal to Interference plus Noise Ratio level be can be set to down
The target of Uplink Control Channel believes dry (the i.e. SINR that makes an uproarCCH target), that is, as shown in above-mentioned formula (5).Meanwhile more into
One step, which may be set to be the target Signal to Interference plus Noise Ratio and down-link data channel of downlink control channel
Target Signal to Interference plus Noise Ratio in biggish one, wherein the target Signal to Interference plus Noise Ratio of the down-link data channel be downlink
The letter of down-link data channel target corresponding to the adoptable all alternative Modulation and Coding Scheme grades of data channel is dry to make an uproar
Minimum value than in.
Specifically, the target Signal to Interference plus Noise Ratio of the down-link data channel is denoted asOn at this point,
The formula (5) that stating will use in step 130 will be rewritten as following formula:
Wherein, i=Cell_IDServing, tmp。
Among one embodiment according to the present invention, when the user equipment is in connection mode and is currently by one
A macro base station is servicing, when the user equipment consider from the macro base station currently serviced for the user equipment be switched to by
Another base station services, if the method will terminate after executing the step 132 according to the present invention, at this time in step
The resulting Signal to Interference plus Noise Ratio level of estimation used in 132 is referred to as the first Signal to Interference plus Noise Ratio level, and the target base switched at this time
It stands and one is set to a micro-base station.
Specifically, it usesIndicate that first Signal to Interference plus Noise Ratio is horizontal, it can be by below
Formula determines:
Among one embodiment according to the present invention, the first Signal to Interference plus Noise Ratio is horizontal
It can be comprised in by being currently sent to the micro-base station as handover-target base station for the user equipment j macro base station serviced
Among switching request message.This point it is not mandatory that, but it is optional.That is, first Signal to Interference plus Noise Ratio is horizontalIt can not also be comprised in and be sent by the macro base station currently serviced for user equipment j
Among the switching request message of the micro-base station as handover-target base station.IfIt is not wrapped
It is contained in the switching request by being currently sent to the micro-base station as handover-target base station for the user equipment j macro base station serviced
Among message, the micro-base station as handover-target base station is to be able to decide whether to receive switching request and can determine to receive to cut
Change is that the user equipment j that will switch plans interface-free resources after requesting.But when
It is comprised in the switching by being currently sent to the micro-base station as handover-target base station for the user equipment j macro base station serviced
When among request message, the micro-base station as handover-target base station being capable of basisCome for
Whether receive switching request and makes more reasonable decision, and the user after decision receives switching request for that will switch
The interface-free resources that will use are made more reasonable planning by equipment j.
The method according to the present invention is not needed using any existing eICIC technical solution, because of downlink control
The inter-cell interference of channel processed (namely exists among the coverage extension bias scheme of enhancing proposed by the invention
When establishing the incidence relation of user equipment and cell) dexterously evaded.Specifically, among method according to the present invention,
When meeting certain Signal to Interference plus Noise Ratio level requirement just realize by the coverage extension of Microcell caused by user equipment with
The association of corresponding Microcell, and then realize and traditional connect based on reference symbol when being unsatisfactory for above-mentioned Signal to Interference plus Noise Ratio level requirement
The cell association for receiving power (RSRP), to efficiently solve the problem of inter-cell interference of above-mentioned down control channel.
It is obvious to a person skilled in the art that invention is not limited to the details of the above exemplary embodiments, Er Qie
In the case where without departing substantially from spirit or essential attributes of the invention, the present invention can be realized in other specific forms.Therefore, no matter
How from the point of view of, the present embodiments are to be considered as illustrative and not restrictive.In addition, it will be evident that one word of " comprising " not
Exclude other elements and steps, and wording "one" be not excluded for plural number.The multiple element stated in device claim can also
To be implemented by one element.The first, the second equal words are used to indicate names, and are not indicated any particular order.
Claims (7)
1. a kind of method in the user equipment of the heterogeneous network of lte-a system for avoiding invalid load balancing, wherein institute
Stating heterogeneous network includes at least one macro base station, at least one micro-base station and at least one described user equipment, and described at least one
A micro-base station will open coverage extension ability, the described method comprises the following steps:
A. the user equipment is based on the reference symbol between the user equipment and at least one described micro-base station calculated
Power is received plus the sum of coverage extension bias gained set by corresponding micro-base station and the user calculated
It is small come the transient service for obtaining the user equipment that reference symbol between equipment and at least one described macro base station receives power
Area's index；
B. if transient service cell index is the index of a macro base station at least one described macro base station or is owning
The index that maximum reference symbol receives the base station of power is generated in macro base station and micro-base station at the user equipment, then it will tool
There is the first base station of the transient service cell index to be determined as the serving BS of the user equipment；
C. otherwise, the base station with the transient service cell index must be micro-base station and the interim cell and use
The incidence relation of family equipment also must be caused by coverage extension is done in corresponding Microcell, at this time then according to by the interim clothes
The Signal to Interference plus Noise Ratio of the user equipment determined by the business cell index horizontal relationship between predetermined threshold determines the use
The serving BS of family equipment, wherein the step (C) further comprises:
C1: if the Signal to Interference plus Noise Ratio level is more than or equal to the predetermined threshold, there will be the transient service cell
The first base station of index is determined as the serving BS of the user equipment；
C2: if the Signal to Interference plus Noise Ratio level is less than the predetermined threshold, judge whether to only include one in all base stations micro-
Base station；
If only including a micro-base station in all base stations, the user equipment directly according to the user equipment with it is described
Reference symbol between each base station in heterogeneous network receives the size of power to determine its serving BS；
If including being greater than or equal to two micro-base stations in all base stations, from the cell index of all base stations
The step of rejecting the transient service cell index in set, then re-executing the method.
2. according to the method described in claim 1, wherein, different bias or phase is arranged at least one described micro-base station
Same bias.
3. according to the method described in claim 2, wherein, when being that at least one described micro-base station is provided with identical bias
When, (C2) simplifies the step of the method are as follows:
If the Signal to Interference plus Noise Ratio level be less than the predetermined threshold, the user equipment directly according to the user equipment with
Reference symbol between each base station receives the size of power to determine its serving BS.
4. according to the method described in claim 1, wherein, the load balancing is since the coverage extension institute of Microcell is real
It is existing, and the invalid load balancing refers to the user equipment quilt that allows caused by the coverage extension by Microcell
The result that first micro-base station is serviced can make the downlink control channel of the user equipment have unacceptable letter dry
It makes an uproar than level.
5. according to the method described in claim 1, wherein, the predetermined threshold, which is that the target letter of downlink control channel is dry, makes an uproar
Than or in the target Signal to Interference plus Noise Ratio of the downlink control channel and the target Signal to Interference plus Noise Ratio of down-link data channel
Biggish one, wherein the target Signal to Interference plus Noise Ratio of the down-link data channel is that down-link data channel is adoptable
Minimum value in down-link data channel target Signal to Interference plus Noise Ratio corresponding to all alternative Modulation and Coding Scheme grades.
6. according to the method described in claim 1, wherein, when the user equipment is in connection mode and is currently by one
Macro base station is servicing, and when user equipment consideration is switched to from the macro base station currently serviced for the user equipment
It is serviced by another base station, if method described in claim 1 will terminate afterwards executing the step (C1), at this time in step
Suddenly the resulting Signal to Interference plus Noise Ratio level of estimation used in (C1) is referred to as the first Signal to Interference plus Noise Ratio level.
7. according to the method described in claim 6, wherein, the first Signal to Interference plus Noise Ratio level can be comprised in by described current
Be sent to for the macro base station that the user equipment is serviced the micro-base station as handover-target base station switching request message it
In, so that the micro-base station as handover-target base station can assist it to then according to the first Signal to Interference plus Noise Ratio level
The no receiving switching request is made decision, and assists it that will switch after determining to receive the switching request
The interface-free resources that will use are made planning by the user equipment.
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| CN102404808A (en) * | 2010-09-14 | 2012-04-04 | 夏普株式会社 | Method for enhanced inter-cell interference cancellation (eICIC) in heterogeneous network, base station and user equipment |
| CN103079211A (en) * | 2012-12-31 | 2013-05-01 | 东南大学 | Heterogeneous network interference coordination method on basis of carrier aggregation |
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| CN102404808A (en) * | 2010-09-14 | 2012-04-04 | 夏普株式会社 | Method for enhanced inter-cell interference cancellation (eICIC) in heterogeneous network, base station and user equipment |
| US8644841B1 (en) * | 2011-03-03 | 2014-02-04 | Sprint Spectrum L.P. | Dynamic adjustment of handoff bias based on load |
| CN103096395A (en) * | 2011-11-04 | 2013-05-08 | 上海贝尔股份有限公司 | Method used for indicating user terminal to reduce interference in base station |
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