CN100534216C - Layering community mobile communication system switching method - Google Patents

Abstract

It is a switching method for Hierarchical Cellular Mobile Communication System, including: (1) detecting the initial lead of two times of time in each preset time period and compute the time interval between the initial lead of adjacent two time; (2) estimating the radial velocity of the users vr, TTRUE_ADV_2 is the initial lead of the back time detected in the process (1), the TTRUE_ADV_1 is the initial lead of the front time detected in the process (1), c for the speed of light. DeltT is the time interval between the initial leads of two time ; (3) The switching control unit receives switching request for crossing the region launched by the user terminals, the current user radial velocity will be compared to the preset radial moving rate to determine the target layer and complete the switch to some small target region from the user terminal. Based on the timing initial lead, the invention calculates the user radial velocity, so it can consider the direction of terminal moving. The estimating value of the user radial velocity is more accurate and reliable.

Description

The changing method of layering community mobile communication system

Technical field

The present invention relates to the changing method of communication system, relate in particular to a kind of changing method of layering community mobile communication system.

Background technology

In cell mobile communication systems, the less sub-district of size can obtain bigger capacity and frequency repeat utilization ratio, yet the user terminal of high-speed mobile will be avoided the problem of frequent handovers in the system that this sub-district less by size formed.And, " focus " area that conversation is relatively concentrated can appear in the system, and as areas such as shopping center, conference centre, commercial buildings, small area jam often appears in those areas, causes the user terminal can not normal talking.Equally, also can occur the blind spot area that signal can't cover in the system, can not carry out talk business at those blind spot area user terminals.In order to solve those problems, layered cell structure is introduced in the cell mobile communication systems.

Layered cell structure is meant multi-zone supervision carried out in the sub-district of cell mobile communication systems, the varying in size of the sub-district between the different levels, and purpose and effect are also inequality.Large-scale sub-district guarantees continuous covering, and small cell then needs to obtain good spectrum efficiency and high capacity.Sub-district among a small circle is used for the terminal that low speed moves and the hot zones of high power capacity, and the sub-district then is used to have the area of the terminal and the low capacity of high-speed mobile characteristic on a large scale.We call the floored community communication system to the cell mobile communication systems with layered cell structure.The sub-district of floored community communication system can be divided into three kinds: macrocell, Microcell and picocell.The coverage maximum of macrocell; The coverage of Microcell is taken second place; The coverage minimum of picocell is generally used for covering chamber's inside radius and is several meters scope.

Fig. 1 is for dividing a structural representation of one deck cell communication systems.This hierarchical communication system is made up of three layers of sub-district, and the form that covers is continuously all taked in the sub-district in every layer.The radius maximum of the sub-district of the top one deck (layer 3), this layer sub-district is called as macrocell.The radius of the sub-district of following one deck (layer 2) takes second place, and this layer sub-district is called as Microcell.The radius minimum of the sub-district of bottom one deck (layer 1) is called as picocell.Seven Microcells are arranged below each macrocell, and also promptly this macrocell covers this seven areas that Microcell covered; Seven picocells are arranged below each Microcell, and also promptly this Microcell covers this seven areas that picocell covered.

When a user walks out a sub-district (macrocell, Microcell or picocell), will trigger handover, this handover might occur between the different layers, also might occur in the same layer.In this article, " on cut " expression user terminal from low layer to high-rise (promptly from layer 1 to layer 2, or from layer 2 to layer 3) process of handover; The process of " switching " expression user terminal handover in same layer (i.e. layer 1, layer 2 or layer 3); " incision " expression user terminal from high level to low layer (promptly from layer 3 to layer 2, or from layer 2 to layer 1) process of handover.Generally speaking, when handover took place, the user terminal that translational speed is low should be dispensed on the less sub-district of size, i.e. sub-district in the layer 1; The user that translational speed is high should be dispensed on larger-size sub-district, i.e. sub-district in the layer 3; The medium user terminal of translational speed should be dispensed on the sub-district in the layer 2.

The sub-district residence time refers to user terminal time of staying a sub-district in communication process.The scheme major part of switching control problem all is based on the sub-district residence time and switches in the existing solution floored community cell mobile communication systems.These schemes can be divided into following two big classes:

(1) based on the memoryless scheme of sub-district residence time

This scheme only uses user terminal at the sub-district of current area residence time the user terminal translational speed to be estimated.

At first define two threshold value τ at the sub-district residence time ₁And τ ₂, and τ ₁＜τ ₂For the user terminal in the layer 2 of system shown in Figure 1, when it initiates hand-off request, it will be used for comparing with two sub-district residence time threshold values of predefined at the residence time t of current area, if t＜τ ₁This user terminal will " on cut ", if t〉τ ₂This user terminal is with " incision ", if τ ₁≤ t≤τ ₂This user terminal will carry out " switching ".Similarly, for the user terminal in the layer 1 of system shown in Figure 1, when it initiated hand-off request, it only need be used for and τ at the residence time t of current area ₁Compare, this user terminal carries out " switching " or " on cut " according to comparative result; For the user terminal in the layer 3 of system shown in Figure 1, when it initiated hand-off request, it only need be used for and τ at the residence time t of current area ₂Compare, this user terminal carries out " switching " or " incision " according to comparative result.

(2) based on the scheme that memory is arranged of sub-district residence time

This scheme uses a plurality of sub-districts residence time of user terminal to estimate the translational speed of this user terminal.About estimation to the user terminal translational speed, can adopt maximum likelihood (ML) criterion, also can adopt least mean-square error criterions such as (MMSE).As an example, provide below adopting the description based on the scheme that memory is arranged of sub-district residence time of ML criterion.

If nearest n sub-district residence time of request handover user terminal is respectively T _D1, T _D2..., T _DnT wherein _D1Current sub-district residence time for this user terminal.The sub-district residence time T of user terminal _Di(i=1 ..., n) to obey negative exponent and distribute, its average is

c _iDepend on the type of switching user terminal: establishing radius of society is R, if request handover user terminal inserts the requesting users terminal at Serving cell for initiation, $c_i=\frac{3\mathrm{\π}}{8R};$ If request handover user terminal is the user terminal of coming from other sub-district handover at Serving cell, $c_i=\frac{\mathrm{\π}}{4R}.$ The translational speed of supposing user terminal is uniformly distributed in [a, b].Estimate by maximum likelihood (ML), can obtain the valuation of user terminal translational speed

$\hat{v}=\frac{n}{{\mathrm{\Π}}_{i=1}^n\left(c_i{T}_{\mathrm{di}}\right)}---\left(1\right)$

If v ₁And v ₂Be two translational speed constants of predefined, and v ₁＜v ₂According to translational speed, intrasystem user terminal can be divided into three groups: [0, v ₁), [v ₁, v ₂) and [v ₂, ∞), layer 1, layer 2 and layer 3 in these three groups of user terminals difference corresponding diagram 1.When user terminal was in cell edge initiation hand-off request, system will be according to handoff command is sent in the valuation of this user terminal translational speed.For the user terminal of the initiation hand-off request of layer 2, if $\hat{v}\&Element;[0,v_1),$ This user terminal will carry out " incision ", if $\hat{v}\&Element;[{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">v</figure-callout>}}_2,\&infin;),$ This user terminal will carry out " on cut ", if $\hat{v}\&Element;[{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">v</figure-callout>}}_1,v_2),$ This user terminal will carry out " switching "; For the user terminal of the initiation hand-off request of layer 1, if $\hat{v}\&Element;[0,v_1),$ This user terminal will carry out " switching ", otherwise this user terminal will " on cut " to layer 2; For the user terminal of the initiation hand-off request of layer 3, if $\hat{v}\&Element;[{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">v</figure-callout>}}_2,\&infin;),$ This user terminal will carry out " switching ", otherwise this user terminal arrives layer 2 with " incision ".

The handover scheme of above-mentioned existing two layering community mobile communication systems all is based on the time of user terminal persistent district as main switching criterion, and the factor of decision user terminal sub-district residence time not only is the size of user terminal translational speed, also should consider to influence or determine other factors of the sub-district residence time of user terminal, the direction that moves as user terminal.

See also Fig. 2, the exemplary plot that it moves for a certain user terminal in the existing layering community mobile communication system.7 sub-districts are Microcell among the figure, when user terminal travels multi-turn to cause this user terminal enough big at the residence time of Serving cell with higher speed along the dotted circle path in current Serving cell (being sub-district 0), sail sub-district shown in the figure 1 then into.If carry out hand-off process based on the memoryless handover scheme of sub-district residence time according to above-mentioned disclosed first kind, this user terminal should carry out " incision ".If have the handover scheme of memory to carry out hand-off process based on the sub-district residence time according to above-mentioned disclosed second kind, this user terminal also should carry out " incision ".Obviously, two kinds of above-mentioned changing methods are not all considered the direction that user terminal moves, it is relatively poor only to calculate the accuracy of rate travel of user terminal according to the sub-district residence time, and also there is certain deviation in the switching type of determining according to the rate travel of user terminal (incision, on cut the still switching of same level).

That is to say that also there is other factors in the factor that influences the user terminal persistent district time except the size of user terminal translational speed, the direction that moves as user terminal.Therefore estimate the rate travel of user terminal simply according to the user terminal persistent district time, there is deviation easily in its value, thereby causes follow-up switching target zone according to the decision of user terminal rate travel also to occur mistake easily.

Summary of the invention

The object of the present invention is to provide a kind of changing method of layering community mobile communication system, to solve in the prior art rate travel of not considering the moving direction of user terminal according to the user terminal persistent district time and estimating user terminal simply, there is deviation easily in its value, and then causes follow-up switching also to have the technical problem of deviation.

In order to address the above problem, the invention provides a kind of changing method of layering community mobile communication system, comprising: (1) detects twice Timing Advance in each default time cycle, calculate the time interval between adjacent twice Timing Advance; (2) utilize $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{<figure-callout\; id="1"\; label="ADV\; \_"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">ADV</figure-callout>}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to movement speed v _r, T _{TRUE_ADV_2}Be the back Timing Advance that step (1) records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step (1) records, c is the light velocity, and Δ T is twice time interval between the Timing Advance; When (3) switch control unit receives this user terminal initiation hand-off request, current user path is compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer.

Step (3) compares to determine that to translational speed and the speed constant of presetting that moves radially destination layer is with current user path:

When the user terminal of layer 2 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge v to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if v _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation, wherein, V _R1And V _R2Move radially velocity constant for predefined two.

User terminal obtains time lead a: T by following steps in the step (1) _{TRUE_ADV}=T _RX-T _TX, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives.

Detect a time lead by following steps in the step (1):

(a1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(a2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, T wherein _RxpathBe the time of reception of first ascending time slot in first subframe of detected terminal use in the base station, T _TSBe the time started of this time slot in the base station.

Step (1) also comprises before: judge whether user terminal is in talking state, if, just carry out step (1), otherwise, do not carry out step (1).

Step (3) is finished user terminal switching of a certain Target cell in the destination layer and is comprised:

(c1) determine to be positioned at the Target cell tabulation of destination layer;

(c2) in the Target cell tabulation, choose the highest sub-district of priority;

(c3) user terminal to hand-off request carries out acceptance judging in selected Target cell, when admitting successfully, switch control unit in the radio network controller (RNC) issues handoff command, indicates described user terminal to be operated in the described Target cell.

The invention discloses the changing method of another kind of layering community mobile communication system, comprising:

(1) user terminal is when network is initiated hand-off request, calculates the time interval between twice Timing Advance and twice Timing Advance;

(2) network side utilization $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{<figure-callout\; id="1"\; label="ADV\; \_"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">ADV</figure-callout>}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to movement speed v _r, and user path compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer,

Wherein, T _{TRUE_ADV_2}Be the back Timing Advance that step (1) records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step (1) records, c is the light velocity, and Δ T is twice time interval between the Timing Advance.

In the step (2) user path is compared to determine that to translational speed and the speed constant of presetting that moves radially destination layer further is:

When the user terminal of layer 2 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge v to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if v _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation,

Wherein, V _R1And V _R2Move radially velocity constant for predefined two.

User terminal obtains time lead a: T by following steps in the step (1) _{TRUE_ADV}=T _RX-T _TX, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives.

Detect a time lead by following steps in the step (1):

(b1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(b2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, wherein, T _RxpathBe the time of reception of first ascending time slot in first subframe of detected terminal use in the base station, T _TSBe the time started of this time slot in the base station.

A kind of layering community mobile communication system that is used for handover, comprise user terminal, base station and radio network controller, also comprise the Timing Advance detecting unit in user terminal or the base station, be used to detect Timing Advance twice, calculate the time interval between adjacent twice Timing Advance;

Comprise also in described base station or the radio network controller that a user path is to the translational speed evaluation unit: be used for utilizing $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{<figure-callout\; id="1"\; label="ADV\; \_"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">ADV</figure-callout>}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Calculate user path to translational speed;

Also comprise switch control unit in the radio network controller: be used for user path is moved radially velocity constant and compares with default two to translational speed, determine the destination layer that switches, and then initiate handoff command, finish handover operation.

Compared with prior art, the present invention has the following advantages: the present invention is based on user path that Timing Advance obtains to translational speed, can consider the direction that terminal moves, therefore the user path that obtains is relatively more accurate and reliable to the valuation of rate travel, thereby makes that the handover of finishing in view of the above is more accurate.

Description of drawings

Fig. 1 is a structural representation of layering community mobile communication system;

Fig. 2 is the exemplary plot that a certain user terminal moves in the existing layering community mobile communication system;

Fig. 3 is the flow chart of the changing method of first kind of layering community mobile communication system disclosed by the invention;

Fig. 4 is that user terminal obtains the schematic diagram that Timing Advance relates to various time parameters in the TD-SCDMA system;

Fig. 5 is the CDMA/TDD hierarchical cellular system is finished switching based on Timing Advance a flow chart;

Fig. 6 is the flow chart of the changing method of another kind of layering community mobile communication system disclosed by the invention.

Embodiment

Below in conjunction with accompanying drawing, specify the present invention.

The scheme major part of switching control problem all is based on the sub-district residence time in the existing solution layering community mobile communication system, and the factor of decision user terminal sub-district residence time not only is the size of user terminal rate travel, and the direction that moves as user terminal can influence or determine the residence time of user terminal in the sub-district equally.But, because obtaining of user terminal translational speed direction is the comparison difficulty, therefore the handoff algorithms in the existing hierarchical cellular system is not all considered the directivity of user terminal translational speed, thereby all can't solve the handover problem of running into as shown in Figure 2.The present invention decides switching controls by the average radial translational speed.No matter this user terminal in the sub-district the 0 resident time how to grow, when this user terminal drives towards sub-district 1 with higher speed, therefore average radial translational speed when it leaves sub-district 0 also is enough big, is easy to determine that user terminal cuts still incision on need carrying out.

The present invention utilizes existing Timing Advance to estimate the distance of terminal to base station.

If the distance of terminal to base station is d, the light velocity is c (3 * 10 ⁸M/s), Timing Advance T then _{TRUE_ADV}Can be expressed as:

$T_{\mathrm{TRUE}\_\mathrm{ADV}}=2\&times;\frac{d}{c}---\left(2\right)$

Can obtain by following formula:

$d=\frac{c\&times;T_{\mathrm{TRUE}\_\mathrm{ADV}}}{2}---\left(3\right)$

If T _{TRUE_ADV_1}And T _{TRUE_ADV_2}Twice result of calculation of the Timing Advance that obtains for the base station, the time interval between twice calculating is Δ T.If with T _{TRUE_ADV_1}The distance of corresponding terminal to base station is d ₁, with T _{TRUE_ADV_2}The distance of corresponding terminal to base station is d ₂Under the prerequisite of ignoring the base station height, can obtain terminal to the valuation of the user path of base station to the size of translational speed:

$v_r=\frac{|d_2-{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="C200510103059E00231.png"\; state="\{\{state\}\}">d</figure-callout>}}_1|}{\mathrm{\&Delta;T}}---\left(4\right)$

For promptness and the accuracy that guarantees valuation, the value of time interval Δ T is unsuitable excessive.Can obtain by (3) formula and (4) formula:

$v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c---\left(5\right)$

Based on above-mentioned disclosed formula, the invention provides the changing method of first kind of layering community mobile communication system.See also Fig. 3, it is the flow chart of the changing method of first kind of layering community mobile communication system disclosed by the invention.

S110: in each default time cycle, detect twice Timing Advance, calculate the time interval between adjacent twice Timing Advance;

S120: utilize $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to movement speed v _r, T _{TRUE_ADV_2}Be the back Timing Advance that step (1) records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step (1) records, c is the light velocity, and Δ T is twice time interval between the Timing Advance;

S130: when switch control unit receives user terminal initiation hand-off request, current user path is compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer.

Below specify each step.

One, specifies step S110

Timing Advance is detected twice in user terminal or base station in each cycle, and calculates the time interval between adjacent twice Timing Advance.With the TD-SCDMA system is example, and how acquisition time lead of user terminal or base station is described.

The account form that user terminal obtains a time lead is: T _{TRUE_ADV}=T _RX-T _TX, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives.

Consider that the base station handles the shared time of this time slot and should leave out from existing Timing Advance, for this reason, obtaining more, the account form of correct time lead is (see also Fig. 4, it obtains the schematic diagram that Timing Advance relates to various time parameters for user terminal in the TD-SCDMA system):

(a1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(a2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, T wherein _RxpathBe the time of reception of first ascending time slot in first subframe of detected terminal use in the base station, T _TSBe the time started of this time slot in the base station.

If the base station need be handled all user terminals in this sub-district and be moved radially speed, can bring a lot of burdens to whole communication network, for this reason, when the user terminal processes talking state, the present invention just carries out step S110, to reduce the burden of communication network: reduce the amount of calculation of base station and the information interaction of minimizing network.

Two, specify step S120

The base station utilizes $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to movement speed v _r, and the user path that will at every turn calculate reports to radio network controller to translational speed, and wherein, T _{TRUE_ADV_2}Be the back Timing Advance that step S110 records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step S110 records, c is the light velocity, and Δ T is twice time interval between the Timing Advance.If Timing Advance is obtained by user terminal, then user terminal is sent to the base station with twice Timing Advance.If Timing Advance is to finish calculating jointly by base station and user terminal, then the base station can directly calculate user path to translational speed.The base station can periodically be sent to radio network controller to translational speed with the user path that is in each user terminal of talking state in this sub-district.In addition, the base station also can be sent to radio network controller with twice Timing Advance, calculates the user path of corresponding user terminal to translational speed by radio network controller.

Three, specifically introduce step S130

Step S130 compares to determine that to translational speed and the speed constant of presetting that moves radially destination layer is with current user path:

When the user terminal of layer 2 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge v to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if v _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation, wherein, V _R1And V _R2Move radially velocity constant for predefined two, the value of these two constants is main relevant with radius of society, and for example the radius of layer 1 sub-district is big more, accordingly constant V _R1Value also big more, concrete optimal value can be determined by system-level emulation.

Describedly finish user terminal switching of a certain Target cell in the destination layer and further comprise:

(c1) determine to be positioned at the Target cell tabulation of destination layer;

(c2) in the Target cell tabulation, choose the highest sub-district of priority;

(c3) user terminal to hand-off request carries out acceptance judging in selected Target cell, and when admitting successfully, radio network controller issues handoff command, indicates described user terminal to be operated in the described Target cell.

Solved the handover problem in the layering community mobile communication system by above-mentioned flow process, considered the directivity of user terminal rate travel, promptly the user path that obtains based on Timing Advance is higher to the accuracy and the reliability of rate travel, the accuracy that causes follow-up district more to be judged thus is higher, makes user terminal can reside in better level.

The present invention is used for the layering community mobile communication system of handover, and it can increase some unit and finish handover of the present invention in original layering community mobile communication system.Such as, on the base station, set up Timing Advance detecting unit and user path to the rate travel evaluation unit, wherein, Timing Advance detecting unit: be used in Preset Time, detecting twice Timing Advance of a certain user terminal, and preserve the time interval between adjacent twice Timing Advance.User path is used for utilizing to the rate travel evaluation unit $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ The user path that estimates the respective user terminal is to translational speed, so that described user path is sent to radio network controller to rate travel and related user terminal information by dispensing device, radio network controller comprises switch control unit, is used for described user path is compared to determine the switching target layer to rate travel and the speed constant of presetting that moves radially.Certainly, the Timing Advance detecting unit also can be arranged on each user terminal.

Below just illustrate how to finish switching (seeing also Fig. 5) based on Timing Advance with the CDMA/TDD hierarchical cellular system.

Step 301, radio network controller are received the handoff request from user terminal, and switching flow is triggered.The handoff request of coming self terminal is the measurement report that terminal reports according to certain principle (as Event triggered).

Step 302 judges whether the user terminal of handoff request is the user terminal of layer 1, is then to enter step 303, otherwise enters step 306.

Step 303, the current user path of the user terminal of judgement handoff request is to the valuation v of translational speed size _rWhether satisfy v _r∈ [0, V _R1), be then to enter step 304, otherwise enter step 305.Work as v _r∈ [0, V _R1) time, the speed that moves radially that this user is described is less and be unlikely frequent handover takes place, so this handoff request user still will be operated in the layer 1.Work as v _r〉=V _R1The time, this user need carry out " on cut " thereby be operated in the layer 2, because the size of layer 2 sub-district is bigger than the size of layer 1 sub-district, can reduce this user's the frequent degree of handover like this.

Step 304, radio network controller are considered factors such as pilot signal power intensity according to the measurement result of terminal to report, satisfy in the selected layer 1 and switch the Target cell that requires, and also promptly determine the tabulation of " switching " Target cell.

Step 305, radio network controller be according to the measurement result of terminal to report, considers factors such as pilot signal power intensity, satisfies in the selected layer 2 and switch the Target cell that requires, and also promptly determines " on cut " Target cell tabulation.

Step 306 judges whether the user terminal of handoff request is the user terminal of layer 2, is then to enter step 307, otherwise enters step 312.If this moment, this user terminal was not the user terminal of layer 2, this terminal must be the user terminal of layer 3.

Step 307 judges that the active user of the user terminal of handoff request moves radially the valuation v of velocity magnitude _rWhether satisfy v _r∈ [0, V _R1), be then to enter step 308, otherwise enter step 309.For the user terminal in the layer 2, when the user path of this terminal to translational speed hour, frequent handover can not take place generally speaking, so when this terminal is sent handoff request, system is operated in sub-district in layer 1 with it.

Step 308, radio network controller are considered factors such as pilot signal power intensity according to the measurement result of terminal to report, satisfy in the selected layer 1 and switch the Target cell that requires, and also promptly determine the tabulation of " incision " Target cell.

Step 309, the current user path of the user terminal of judgement handoff request is to the valuation v of translational speed size _rWhether satisfy v _r∈ [V _R2, ∞), be then to enter step 310, otherwise enter step 311.For the user terminal in the layer 2, when the user path of this terminal when translational speed is big, if still be operated in layer, frequent handover will take place, so when terminal was sent handoff request, system should allow the sub-district of described terminal works in layer 3.

Step 310, radio network controller be according to the measurement result of terminal to report, considers factors such as pilot signal power intensity, satisfies in the selected layer 3 and switch the Target cell that requires, and also promptly determines " on cut " Target cell tabulation.

Step 311, the current valuation v that moves radially velocity magnitude of the user terminal of handoff request _rNecessarily satisfy v _r∈ [V _R1, V _R2), radio network controller is considered factors such as pilot signal power intensity according to the measurement result of terminal to report, satisfies in the selected layer 2 and switches the Target cell that requires, and also promptly determines the tabulation of " switching " Target cell.

Step 312 judges that the active user of the user terminal of handoff request moves radially the valuation v of velocity magnitude _rWhether satisfy v _r∈ [V _R2, ∞), be then to enter step 313, otherwise enter step 314.The radius of society maximum of layer in 3 is suitable for the user terminal of high-speed mobile.For the user terminal in the layer 3, when the user path of this terminal less and satisfy v to translational speed _r＜V _R2The time, system should be when it sends handoff request be operated in it sub-district in layer 2.

Step 313, radio network controller are considered factors such as pilot signal power intensity according to the measurement result of terminal to report, satisfy in the selected layer 3 and switch the Target cell that requires, and also promptly determine the tabulation of " switching " Target cell.

Step 314, radio network controller are considered factors such as pilot signal power intensity according to the measurement result of terminal to report, satisfy in the selected layer 2 and switch the Target cell that requires, and also promptly determine the tabulation of " incision " Target cell.

Step 315 is selected optimum sub-district from the Target cell tabulation.

Step 316 is carried out acceptance judging to the hand-off request user in selected Target cell, if success then enter step 319, otherwise would enter step 317.Operable resource situation in the selected sub-district is depended in the acceptance judging success or not.

Step 317 judges whether the Target cell tabulation is empty, if be empty, this switching flow finishes, and terminal continues in former cell operation, otherwise enters step 318.The Target cell tabulation means that for empty the user terminal of hand-off request does not have operable new sub-district, therefore can't carry out handover.

Step 318 is selected next optimum sub-district from the Target cell tabulation.

Step 319, radio network controller issues handoff command, and indicating terminal is operated in the sub-district of new appointment.This handoff command can be that physical channel such as reshuffles at message.

Terminal is received from inserting in the sub-district of appointment after the handoff command of radio network controller, then according to inserting success or not to radio network controller feedback handover success or failure.Radio network controller is deleted corresponding processing such as former sub-district link or deletion Target cell link according to the feedback of the terminal that receives.

User terminal is in communication process, and base station or user terminal need calculate twice Timing Advance and preserve time interval between this twice Timing Advance at certain hour in the cycle.And the user path that this user terminal also need be calculated in the base station is to rate travel and report to radio network controller.The user terminal that is in communication process when user terminal shared time in communication process in the long or base station can take a large amount of processing time of base station and handle resource more for a long time.For this reason, the invention provides the changing method of another kind of layering community mobile communication system.See also Fig. 6, it is the switching flow figure of another kind of floored community communication system of the present invention.It comprises:

S210: when user terminal was initiated hand-off request to network side, this terminal and/or base station were detected Timing Advance twice, and calculate twice the time interval between the Timing Advance.

User terminal obtains time lead a: T by following steps among the step S210 _{TRUE_ADV}=T _RX-T _TX, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXBe the time of user terminal according to a certain descending time slot that receives, by the time started of first ascending time slot in first subframe that calculates this terminal use, when user terminal when network side is initiated hand-off request, this user terminal obtains the time interval between current twice Timing Advance and twice Timing Advance by the way, and the time interval between twice Timing Advance that will obtain and twice Timing Advance reports to base station or switch control unit.

Step S210 can also detect a time lead by following steps:

(b1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(b2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, T wherein _RxpathBe the time of reception of first ascending time slot in first subframe of the detected terminal use in base station, T _TSBe the time started of this time slot in the base station.

S220: the switch control unit utilization of network side $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to movement speed v _r, and user path compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer, wherein, T _{TRUE_ADV_2}Be the back Timing Advance that step S210 records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step S210 records, c is the light velocity, and Δ T is twice time interval between the Timing Advance.

The user path that the base station can estimate this user terminal correspondence earlier is sent to radio network controller with user path to translational speed and described user terminal information then to translational speed.The base station also can be directly reports to radio network controller with the time interval between twice Timing Advance and twice Timing Advance, calculates the user path of this user terminal correspondence to translational speed by radio network controller.User path compares to determine that to translational speed and the speed constant of presetting that moves radially destination layer further is:

When the user terminal of layer 2 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge v to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if v _r∈ [0, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if v _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation, wherein, V _R1And V _R2Move radially velocity constant for predefined two.

Utilize said method to finish handover, not only can accurately find destination layer, but also can reduce user path reduces burden from network side to the amount of calculation of translational speed.

More than disclosed only be several specific embodiment of the present invention, but the present invention is not limited thereto, any those skilled in the art can think variation, all should drop in protection scope of the present invention.

Claims (9)

1, a kind of changing method of layering community mobile communication system is characterized in that, comprising:

(1) utilizes T _TRUE-ADV=T _RX-T _TXObtain Timing Advance, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives; In each default time cycle, detect twice Timing Advance, calculate the time interval between adjacent twice Timing Advance;

(2) utilize $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to translational speed ν _r, T _{TRUE_ADV_2}Be the back Timing Advance that step (1) records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step (1) records, c is the light velocity, and Δ T is twice time interval between the Timing Advance;

When (3) switch control unit receives this user terminal initiation hand-off request, current user path is compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer.

2, the changing method of layering community mobile communication system as claimed in claim 1 is characterized in that, step (3) compares to determine that to translational speed and the speed constant of presetting that moves radially destination layer is with current user path:

When the user terminal of layer 2 is initiated hand-off request, if ν _r∈ [ ₀, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge ν to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if ν _r∈ [ ₀, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if ν _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation,

Wherein, V _R1And V _R2Move radially speed constant for predefined two.

3, the changing method of layering community mobile communication system as claimed in claim 1 or 2 is characterized in that, detects a time lead by following steps in the step (1):

(a1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(a2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, wherein, T _RxpathBe the time of reception of first ascending time slot in first subframe of detected terminal use in the base station, T _TSBe the time started of this time slot in the base station.

4, the changing method of layering community mobile communication system as claimed in claim 1 is characterized in that, step (1) also comprises before: judge whether user terminal is in talking state, if, just carry out step (1), otherwise, do not carry out step (1).

5, the changing method of layering community mobile communication system as claimed in claim 1 or 2 is characterized in that, step (3) is finished user terminal switching of a certain Target cell in the destination layer and comprised:

(c1) determine to be positioned at the Target cell tabulation of destination layer;

(c2) in the Target cell tabulation, choose the highest sub-district of priority;

(c3) user terminal to hand-off request carries out acceptance judging in selected Target cell, and when admitting successfully, switch control unit issues handoff command, indicates described user terminal to be operated in the described Target cell.

6, a kind of changing method of layering community mobile communication system is characterized in that, comprising:

(1) utilizes T _TRUE-ADV=T _RX-TTXObtain Timing Advance, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives; When user terminal is initiated hand-off request to network, calculate the time interval between twice Timing Advance and twice Timing Advance;

(2) the switch control unit utilization of network side $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Estimate user path to translational speed ν _r, and user path compared to determine destination layer to the translational speed and the default speed constant that moves radially, finish the switching of user terminal a certain Target cell in the destination layer,

Wherein, T _{TRUE_ADV_2}Be the back Timing Advance that step (1) records, T _{TRUE_ADV_1}Be the preceding Timing Advance that step (1) records, c is the light velocity, and Δ T is twice time interval between the Timing Advance.

7, the changing method of layering community mobile communication system as claimed in claim 6 is characterized in that, in the step (2) user path is compared to determine that to translational speed and the speed constant of presetting that moves radially destination layer further is:

When the user terminal of layer 2 is initiated hand-off request, if ν _r∈ [ ₀, V _R1), then described user terminal is carried out the handover operation of incision, otherwise further judge ν to layer 1 _r∈ [V _R2, ∞) whether set up, if cut to the handover operation of layer 3 on then described user terminal being carried out, otherwise described user terminal carries out the handover operation of same level;

When the user terminal of layer 1 is initiated hand-off request, if ν _r∈ [ ₀, V _R1), then described user terminal is carried out the handover operation of same level, otherwise switch to the handover operation of layer 2 on described user terminal carried out;

When the user terminal of layer 3 is initiated hand-off request, if ν _r∈ [V _R2, ∞), then this user terminal is carried out the handover operation of same level, otherwise this user terminal is descended to switch to layer 2 handover operation,

Wherein, V _R1And V _R2Move radially speed constant for predefined two.

8, as the changing method of claim 6 or 7 described floored community communication systems, it is characterized in that, detect a time lead by following steps in the step (1):

(b1) user terminal detects T earlier _RX, T _TX, then according to T _ADV=T _RX-T _TXCalculate T _ADV, subsequently with described T _ADVReport to the base station, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives;

(b2) base station detects T earlier _TS, T _Rxpath, then according to T _Rxdev=T _TS-T _RxpathCalculate T _Rxdev, subsequently according to T _{TRUE_ADV}=T _ADV-T _Rxdev, calculate Timing Advance T _{TRUE_ADV}, wherein, T _RxpathBe the time of reception of first ascending time slot in first subframe of detected terminal use in the base station, T _TSBe the time started of this time slot in the base station.

9, a kind of layering community mobile communication system that is used for handover comprises user terminal, base station and radio network controller, it is characterized in that,

Also comprise the Timing Advance detecting unit in user terminal or the base station, be used to utilize T _TRUE-ADV=T _RX-T _TXObtain Timing Advance, wherein, T _TXFor user terminal sends time of first ascending time slot in first subframe, T _RXIt is the time of user terminal, by the time started of first ascending time slot in first subframe that calculates this terminal use according to a certain descending time slot that receives; And detect Timing Advance twice, calculate the time interval between adjacent twice Timing Advance;

Comprise also in described base station or the radio network controller that a user path is to the translational speed evaluation unit: be used for utilizing $v_r=\frac{|T_{\mathrm{TRUE}\_\mathrm{ADV}\_2}-T_{\mathrm{TRUE}\_\mathrm{ADV}\_1}|}{2\mathrm{\&Delta;T}}\&times;c$ Calculate user path to translational speed; Wherein, ν _rFor user path to translational speed, T _{TRUE_ADV_2}Be the back Timing Advance that described Timing Advance detecting unit records, T _{TRUE_ADV_1}Be the preceding Timing Advance that the Timing Advance detecting unit records, c is the light velocity, and Δ T is twice time interval between the Timing Advance;

Also comprise switch control unit in the radio network controller: be used for user path is moved radially velocity constant and compares with default two to translational speed, determine the destination layer that switches, and then initiate handoff command, finish handover operation.

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