CN104469898A - Method for discovering small stations based on graph coloring in ultra-dense wireless network - Google Patents

Method for discovering small stations based on graph coloring in ultra-dense wireless network Download PDF

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Publication number
CN104469898A
CN104469898A CN201410798882.0A CN201410798882A CN104469898A CN 104469898 A CN104469898 A CN 104469898A CN 201410798882 A CN201410798882 A CN 201410798882A CN 104469898 A CN104469898 A CN 104469898A
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China
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small station
small
synchronizing signal
reuse
station
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CN201410798882.0A
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Chinese (zh)
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潘志文
彭帅
刘楠
尤肖虎
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东南大学
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W48/00Access restriction; Network selection; Access point selection
    • H04W48/16Discovering, processing access restriction or access information

Abstract

The invention discloses a method for discovering small stations based on graph coloring in an ultra-dense wireless network. The method comprises the steps that the number of small station groups, namely the available color number Ncolors, is determined by an operator; a multiplex distance dreuse which is as big as possible is found under the premise that the used color number is not larger than the Ncolors; an interference relation graph is established according to the dreuse, and a Brelaz algorithm is used for coloring; the small stations are grouped according to coloring results, and all groups of small stations are made to send synchronous signals in turn; when network topology changes, the interference relation graph is reestablished, coloring is conducted again, the small stations are regrouped, and the small stations are made to send synchronous signals in turn according to the new groups. According to the method, the small stations are grouped, the interference of the synchronous signals of different small stations is reduced; the interference relations between the small stations are reflected through the interference relation graph, so that the small stations which interfere with each other seriously are prevented from being distributed in the same group, and the interference between the small stations is further reduced; the probability that UE discovers weak small stations is improved, and the number of the small stations discovered by the UE is increased.

Description

Based on the small station discover method of graph coloring in super-intensive wireless network

Technical field

The invention belongs to the Cell searching technical field in radio communication, be specifically related to the small station discover method in super-intensive wireless network (Hyper-Dense Wireless Networks).

Background technology

Along with intelligent terminal is popularized, increasing fast appears in mobile data services.When spectrum efficiency be difficult to further raising, increase bandwidth cost high, increase cell density become reply this trend important method.

LTE-A (Long Term Evolution-Advanced) is by the deploy small-cell, macrocell basis in Cellular Networks topology, as Femto cell (Femtocell), picocell (Picocell) and relaying (Relay) etc., realize the optimization to indoor, hot zones and cell boarder.These small-cells are realized covering by low power nodes (LPN, Low Power Node, also known as small station).Because small station is under the covering of macrocell (Macrocell), on existing cellular topology, form the topology of another layer, constitute the isomerism network (HetNet, Heterogeneous Network) of layering.

Since LTE Release 10, to the support in small station with to strengthen be 3GPP (3 always rdgenerationPartnership Project) tissue reply data service increase an important evolution tendency.On the basis of HetNet, introduce small station at the LTE Release 12 formulated and strengthen (Small Cell Enhancement, SCE) scene.Compared with HetNet, the small station of SCE is deployed in the hot spot region of macrocell, more crypto set, and cluster distribution.And in the super-intensive wireless network in future, small station is disposed and incited somebody to action more crypto set, hundreds of of each macrocell can be reached.

It is exactly that UE (User Equipment) detects small station and the process measuring its RSRP (ReferenceSignal Received Power)/RSRQ (Reference Signal Received Quality) that small station finds.

In super-intensive wireless network, due to the dense deployment in small station, between small station, the interference of synchronizing signal and reference signal is strong, finds that difficulty is caused in small station to UE.And the characteristics such as small station switch (small cell on/off), load balancing, e-ICIC (enhanced-Inter-Cell Interference Coordination), CoMP (Coordinated Multi-point Transmission) all require efficiently, small station discovery fast, find to propose higher performance requirement to small station.Research shows, existing cell search scheme can not meet the requirement that super-intensive network middle and small stations finds.

For solving foregoing problems, small station is found a research direction as LTE Release 12 small station enhanced scene by 3GPP RAN1.Industry has many companies and mechanism conducts a research at this point, and proposes a large amount of relevant motion to 3GPP.Wherein, the solution of network side is reduced interference by the multiplexing factor improving synchronizing signal at time domain/frequency domain, is improved detection perform.A kind of solution for SCE scene is that order sends synchronizing signal in turn with the small station in cluster.But because super-intensive wireless network middle and small stations is very intensive, the interference relationships between small station is very complicated, to send simply in turn for super-intensive wireless network and inapplicable.More effective small station discover method must be designed for the feature of super-intensive wireless network.

Summary of the invention

The object of this invention is to provide the small station discover method in a kind of super-intensive wireless network, configure the opportunity that each small station sends synchronizing signal.Adopt the small station in the present invention to send configuration on opportunity, the interference between the synchronizing signal that significantly can reduce different small station, thus improve the number that UE finds small station.

Technical scheme of the present invention: first utilize interference relationships figure to reflect disturbed condition between small station, then adopt the graph coloring algorithm of improvement to this interference relationships graph coloring, and according to colouring results, divided into groups in small station, the small station of the different group of finally order sends synchronizing signal in turn, thus reaches the object reducing interference.

Based on a small station discover method for graph coloring in super-intensive wireless network, it is characterized in that, said method comprising the steps of:

The number divided into groups in small station is determined, i.e. available number of colours N by operator colors;

Find one to meet number of colours used and be not more than N colorsprerequisite under large as far as possible multiplex distance d reuse;

According to d reusebuild interference relationships figure and adopt Brelaz algorithm painted;

According to colouring results, is divided into groups in small station, make each group of small station send synchronizing signal in turn;

When network topology changes, rebuild interference relationships figure, painted, is divided into groups again in small station, make small station send synchronizing signal in turn by new grouping.

Preferably, determined to comprise the number divided into groups in small station by operator:

For enabling UE find multiple small station rapidly, all small stations distribute one and take turns synchronizing signal required time no more than 100ms;

In order to utilize the gain that bring different from rear field SSS of front field in LTE system, getting and often organizing small station transmission synchronizing signal duration is radio frames, i.e. a 10ms;

Wherein, N colorsbe not more than 10.

Preferably, find one to meet number of colours used and be not more than N colorsprerequisite under large as far as possible d reuse, specifically comprise:

The number of colours finding a corresponding interference relationships figure with binary chop and Brelaz algorithm is N colorsd reuse;

Wherein, the historical data of the concrete situation that the upper bound and lower bound are disposed according to local wireless network middle and small stations by operator and Operation Network is determined, wherein, the concrete situation that small station is disposed comprises number and the density in small station;

Dichotomy is adopted to find a d reuseafter, increase d reuseuntil the number of colours of the interference relationships figure of correspondence is greater than N colors, then by d reusereduce a step-length.

Preferably, according to d reusebuild interference relationships figure and adopt Brelaz algorithm painted, comprising:

Each summit represents a small station;

To any two small stations, if its distance is less than or equal to d reuse, then with a limit, the summit of correspondence is coupled together, represents to there is interference between these two small stations;

Adopt Brelaz algorithm to interference relationships graph coloring.

Preferably, according to colouring results, is divided into groups in small station, makes each group of small station send synchronizing signal in turn, comprising:

Divided into groups in small station, the small station with same color is in same group;

The small station of different grouping is made to send synchronizing signal in turn;

Configuration small station being sent synchronizing signal opportunity notifies UE by network signal;

The transmission that small station is specified according to macro station sends synchronizing signal opportunity;

UE sends synchronizing signal according to the small station that network signal notifies and performs Cell searching opportunity, finds small station.

Preferably, when network topology changes, rebuild interference relationships figure, painted, divided into groups again in small station, make small station send synchronizing signal in turn by new grouping, comprising:

When discovery network topology changes, namely pick up one and meet number of colours used and be not more than N colorsprerequisite under large as far as possible d reuse;

Re-construct interference relationships figure;

Again adopt Brelaz algorithm painted;

Again is divided into groups by color in small station, make each group of small station send synchronizing signal in turn.

The present invention has technique effect useful as follows: provide a kind of new small station discover method.Configure by the method the opportunity that each small station sends synchronizing signal, the interference between the synchronizing signal of each small station can be reduced, thus improve the probability that UE finds more small and weak station, increase UE institute detectable small station number.

Have the following advantages based on small station of the present invention discover method tool:

1. this method is deployed in eNodeB end, and is deployed in compared with small station discover method that UE holds, can not increase complexity and the power consumption of UE.

2. this method is based on existing synchronizing signal PSS (Primary Synchronization Signal) and SSS (Secondary Synchronization Signal), less to the change of LTE prior art specification.

3. this method utilizes interference relationships figure to reflect the interference relationships between small station, the small station of mutual serious interference is avoided to be in same group when dividing into groups, reduce the interference between small station, thus improve the probability that UE finds more small and weak station, add UE institute detectable small station number.

Accompanying drawing explanation

Fig. 1 is the structure of interference relationships figure and painted schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the execution mode of the present invention in LTE super-intensive wireless network is described further:

The structure of 1 interference relationships figure

Interference relationships figure is a non-directed graph C=(V, E).Wherein V is the set on all summits in figure, and each summit represents a small station; E is the set on all limits in figure, and every bar limit all represents to there is interference between two small stations.

Owing to not having the information such as SINR (Signal to Interference and NoiseRatio), the RSRP in small station at initial search phase UE, so utilize the geographical location information in small station, i.e. the position in small station, builds interference relationships figure.Distance between small station is nearer, just thinks that the interference between small station is stronger.

Assuming that small inter-site distance is from being greater than multiplex distance d reusein time, is disturbed and can ignore, and builds interference relationships figure in the following way: each summit represents a small station; Distance when between two small stations is less than or equal to d reuse, then with a limit, the summit of correspondence is coupled together.

Illustrate below by an example, as shown in Figure 1, definition d i, jfor the distance between small station i and small station j.In the drawings, d i,j(2≤i≤j≤5) and d 1,2be less than or equal to d reuse, all the other distances are all greater than d reuse.The interference relationships figure then constructed is as shown in Fig. 1 right-hand component.Wherein the existence of limit (i, j) represents d i,j≤ d reuse.

The 2 graph coloring algorithms improved

After interference relationships figure has built, namely the problem of small station grouping is converted into the problem of graph coloring, namely under the constraint of same color must not be caught in the summit with common edge, is graph coloring by minimum color.

Brelaz algorithm is the graph coloring algorithm of the classics often adopted in allocation of radio resources.Brelaz algorithm can produce a k color rendering intent to the colorable figure of nearly all k.But pinpointed the problems in the small station of super-intensive wireless network, Brelaz algorithm can not directly be suitable for.Here make improvements, by the structure of interference relationships figure with paintedly to join together:

(1) first determine by operator the number divided into groups in small station, i.e. available number of colours N colors.N colorsoften organize small station to send synchronizing signal duration and jointly determine all small stations and distribute one and take turns synchronizing signal required time.For enabling UE find multiple small station rapidly, all small stations distribute one and take turns synchronizing signal required time no more than 100ms.In order to utilize the gain that bring different from rear field SSS of front field in LTE system, getting and often organizing small station transmission synchronizing signal duration is radio frames, i.e. a 10ms.Therefore N colorsshould not 10 be greater than.

(2) then, find one to meet number of colours used accordingly and be not more than N colorsprerequisite under large as far as possible d reuse.Consider that the number of colours of interference relationships figure is along with d reusedull growth, is determining d reusebinary chop is adopted in process.Wherein, the upper bound and the lower bound concrete situation (number in small station and density) of being disposed according to local wireless network middle and small stations by operator and the historical data of Operation Network are determined.

(3) last according to d reusebuild interference relationships figure and adopt Brelaz algorithm painted.

In addition, consider that the complexity of Brelaz algorithm is O (| V|), wherein | V| is the number on summit, is to reduce amount of calculation, builds interference relationships figure respectively to the small station of each macrocell.

When network topology changes, open as small station or close, namely interference relationships figure being rebuild, restained.

The concrete steps of the graph coloring algorithm improved are as shown in the table.

The graph coloring algorithm that table 1 improves

When interference relationships figure structure and paintedly to complete, by color, can be divided into groups in small station, make each group to send synchronizing signal in turn.

Wherein apply the concrete steps of Brelaz algorithm to interference relationships graph coloring as shown in the table.

When algorithm starts, color pond is empty.What the degree on a summit referred to this summit faces subapical quantity, namely has the quantity on the summit of common edge with this summit.The saturation on a summit is defined as all number of color closed on used by summit on this summit.If it is all different that a kind of color and certain not painted summit all face subapical color, then this summit of this Color pair is claimed to be available.

The Brelaz algorithm of table 2 graph coloring

Still illustrate with Fig. 1.Vertex v 2there is maximum degree, be therefore first colored, be assumed to be color 1.Next summit to be colored is from v 3, v 4and v 5in select, because they all have identical degree and saturation.Suppose to select v 5as next one summit to be colored.Now for v 5, color does not have colors available in pond, therefore newly adds a kind of color in color pond, is assumed to be color 2, and is v by this color 5painted.Then algorithm proceeds, until all summits are all colored.After having dyeed, all small stations are divided into 4 groups by according to color; Its middle and small stations 1 is with small station 5 at same group, and all the other small stations are respectively one group.Each group of small station sends synchronizing signal in turn.

The flow process of the specific embodiment of the invention is as follows:

(1) macro station is in conjunction with the actual deployment situation determination colors available number N in small station in macrocell colors.

(2) macro station adopts binary chop and Brelaz algorithm to find the maximum d meeting the requirement of colors available number reuse.

(3) macro station is according to d reusebuild the interference relationships figure in small station in macrocell, and painted to it according to Brelaz algorithm.

(4) according to colouring results, is divided into groups in small station, make the small station of different grouping send synchronizing signal in turn, and configuration small station being sent synchronizing signal opportunity notifies UE by network signal.

(5) transmission that small station is specified according to macro station sends synchronizing signal opportunity.

(6) UE sends synchronizing signal according to the small station that network signal notifies and performs Cell searching opportunity, finds small station.

(7) when network topology changes, then step (2) is got back to.

Above-described embodiment, only for technical conceive of the present invention and feature are described, its object is to person skilled in the art can be understood content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalent transformations of doing according to Spirit Essence of the present invention or modification, all should be encompassed within protection scope of the present invention.

Claims (6)

1. in super-intensive wireless network based on a small station discover method for graph coloring, it is characterized in that, said method comprising the steps of:
The number divided into groups in small station is determined, i.e. available number of colours N by operator colors;
Find one to meet number of colours used and be not more than N colorsprerequisite under large as far as possible multiplex distance d reuse;
According to d reusebuild interference relationships figure and adopt Brelaz algorithm painted;
According to colouring results, is divided into groups in small station, make each group of small station send synchronizing signal in turn;
When network topology changes, rebuild interference relationships figure, painted, is divided into groups again in small station, make small station send synchronizing signal in turn by new grouping.
2. in a kind of super-intensive wireless network according to claim 1 based on the small station discover method of graph coloring, it is characterized in that, determined to comprise the number divided into groups in small station by operator:
For enabling UE find multiple small station rapidly, all small stations distribute one and take turns synchronizing signal required time no more than 100ms;
In order to utilize the gain that bring different from rear field SSS of front field in LTE system, getting and often organizing small station transmission synchronizing signal duration is radio frames, i.e. a 10ms;
Wherein, N colorsbe not more than 10.
3. in a kind of super-intensive wireless network according to claim 1 based on the small station discover method of graph coloring, it is characterized in that, find one to meet number of colours used and be not more than N colorsprerequisite under large as far as possible d reuse, specifically comprise:
The number of colours finding a corresponding interference relationships figure with binary chop and Brelaz algorithm is N colorsd reuse;
Wherein, the historical data of the concrete situation that the upper bound and lower bound are disposed according to local wireless network middle and small stations by operator and Operation Network is determined, wherein, the concrete situation that small station is disposed comprises number and the density in small station;
Dichotomy is adopted to find a d reuseafter, increase d reuseuntil the number of colours of the interference relationships figure of correspondence is greater than N colors, then by d reusereduce a step-length.
4. in a kind of super-intensive wireless network according to claim 1 based on the small station discover method of graph coloring, it is characterized in that, according to d reusebuild interference relationships figure and adopt Brelaz algorithm painted, comprising:
Each summit represents a small station;
To any two small stations, if its distance is less than or equal to d reuse, then with a limit, the summit of correspondence is coupled together, represents to there is interference between these two small stations;
Adopt Brelaz algorithm to interference relationships graph coloring.
5. in a kind of super-intensive wireless network according to claim 1 based on the small station discover method of graph coloring, it is characterized in that, according to colouring results, is divided into groups in small station, make each group of small station send synchronizing signal in turn, comprising:
Divided into groups in small station, the small station with same color is in same group;
The small station of different grouping is made to send synchronizing signal in turn;
Configuration small station being sent synchronizing signal opportunity notifies UE by network signal;
The transmission that small station is specified according to macro station sends synchronizing signal opportunity;
UE sends synchronizing signal according to the small station that network signal notifies and performs Cell searching opportunity, finds small station.
6. in a kind of super-intensive wireless network according to claim 1 based on the small station discover method of graph coloring, it is characterized in that, when network topology changes, rebuild interference relationships figure, painted, is divided into groups again in small station, makes small station send synchronizing signal in turn by new grouping, comprising:
When discovery network topology changes, namely pick up one and meet number of colours used and be not more than N colorsprerequisite under large as far as possible d reuse;
Re-construct interference relationships figure;
Again adopt Brelaz algorithm painted;
Again is divided into groups by color in small station, make each group of small station send synchronizing signal in turn.
CN201410798882.0A 2014-12-19 2014-12-19 Method for discovering small stations based on graph coloring in ultra-dense wireless network CN104469898A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104717722A (en) * 2015-04-01 2015-06-17 东南大学 PSS interference elimination-based small cell discovery method in ultra dense wireless network
CN105207759A (en) * 2015-08-14 2015-12-30 清华大学 Pilot frequency multiplexing method with multiplexing factor of 4 in super-dense networking
CN105578478A (en) * 2016-01-21 2016-05-11 桂林电子科技大学 Spectrum auction method of fractional order frequency multiplexing
WO2017012340A1 (en) * 2015-07-17 2017-01-26 中兴通讯股份有限公司 Network element grouping method and apparatus, and communications system
CN106937391A (en) * 2017-04-12 2017-07-07 东南大学 A kind of super-intensive heterogeneous network system efficiency maximizes user-association optimization method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104066147A (en) * 2013-03-19 2014-09-24 中兴通讯股份有限公司 Network node searching method, device and equipment based on downlink detection reference signal

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104066147A (en) * 2013-03-19 2014-09-24 中兴通讯股份有限公司 Network node searching method, device and equipment based on downlink detection reference signal

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
INTEL CORPORATION: "《R1-133207 3GPP TSG RAN WG1 Meeting #74》", 23 August 2013 *
QIAN ZHANG, ETC: "A Coloring-based Resource Allocation for OFDMA Femtocell Networks", 《2013 IEEE WIRELESS COMMUNICATION AND NETWORKING CONFERENCE》 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104717722A (en) * 2015-04-01 2015-06-17 东南大学 PSS interference elimination-based small cell discovery method in ultra dense wireless network
CN104717722B (en) * 2015-04-01 2018-05-15 东南大学 The small station eliminated in ultra dense set network based on PSS interference finds method
WO2017012340A1 (en) * 2015-07-17 2017-01-26 中兴通讯股份有限公司 Network element grouping method and apparatus, and communications system
CN106712980A (en) * 2015-07-17 2017-05-24 中兴通讯股份有限公司 Network element grouping method and device, and communication system
CN105207759A (en) * 2015-08-14 2015-12-30 清华大学 Pilot frequency multiplexing method with multiplexing factor of 4 in super-dense networking
CN105578478A (en) * 2016-01-21 2016-05-11 桂林电子科技大学 Spectrum auction method of fractional order frequency multiplexing
CN105578478B (en) * 2016-01-21 2019-03-29 桂林电子科技大学 A kind of spectrum auction method of fractional order channeling
CN106937391A (en) * 2017-04-12 2017-07-07 东南大学 A kind of super-intensive heterogeneous network system efficiency maximizes user-association optimization method

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