CN104735681A - Method for setting LTE network in high-speed rail environment - Google Patents

Abstract

The invention provides a method for setting the LTE network in a high-speed rail environment. The LTE network comprises N base stations and antennae, wherein N is larger than 1, the base stations are distributed on the two sides of a railway in a stagger and zigzag mode, the incidence angle theta of each base station is not smaller than 10 degrees, the vertical distance D between each base station and the edge of the railway meets the inequation that S/2*tan theta<D<S/2, S represents station spacing, and theta is the minimum incidence angle. By the adoption of the method, through targeted network plan of the high-speed rail scene, the high-quality LTE network can be provided for an operator, adverse effects caused by various factors during high-speed running of a train are reduced, signal quality is guaranteed, and user experience is improved.

Description

The method to set up of LTE network in high ferro environment

Technical field

The present invention relates to the communications field, particularly relate to the method to set up of LTE network in a kind of high ferro environment.

Background technology

Whole nation high-speed railway planning construction is planned for the year two thousand twenty, will set up Planning of Express Passenger Corridor between provincial capital and big and medium-sized cities, comprises " four vertical four is horizontal " railway Planning of Express Passenger Corridor and three intercity personal rapid transit systems.Expect the year two thousand twenty, the high speed railway construction mileage of 200 kilometers, China and above speed per hour more than 1.8 ten thousand kilometers, will will account for the over half of world's high-speed railway total kilometrage.

It is long that high speed high ferro covers mileage, and the passenger's spare time taking high speed high ferro is many, large to network demand, not only comprises voice demand, video requirement, also has high speed data requirements.But existing 3G network railway covering quality is poor, the growing voice of passenger and data traffic requirement can not be met, therefore signal is good, covering is wide, high speed high ferro LTE network that is that surf the Net fast is very important to build one, can not only increase health service revenue, promote user awareness, be also of great advantage to the image construction of operator.

After train speed raising, vehicle travel speed in dedicated track is fast, owing to being subject to rapid fading in high speed movement, Doppler effect, train material to the impact of the many factors such as radio signal attenuation and dereliction coverage cell, when in car, cellphone subscriber carries out mobile communication, often easily occur switching chaotic, cannot connect, the phenomenon such as abnormal call drop.To sum up, the special network characteristic complicated again of high speed high ferro brings no small problem to mobile communication.

Summary of the invention

The object of the present invention is to provide the method to set up of LTE network in a kind of high ferro environment, reduce the harmful effect of many factors in train high speed movement.

The object of the invention is to be achieved through the following technical solutions.

A method to set up for LTE network in high ferro environment, described LTE network comprises N number of base station and antenna, described N > 1; Described base station is interspersed in railway both sides, in "the" shape cloth station; The incidence angle θ of described base station is not less than 10 degree; The scope of described base station distance Along Railway vertical range D is: S/2*tan θ < D < S/2, S is wherein base station station spacing, θ is minimum incidence angle.

Wherein, for the base station of bend corner region being arranged at described railway, this base station is arranged in bend turning.

Wherein, along the railway, the region that periphery user is few or railway is straight wherein, described antenna adopts high-gain narrow beam antenna; Urban district wherein, suburb, have station or railway to have the region of radian on the way, described antenna adopts medium gain antenna; Tunnel area wherein, described antenna adopts and leaks cable.

Wherein, described base station adopts binary channels RRU to cover networking mode.

Wherein, described binary channels RRU covers networking mode and comprises: the two RRU two-way coverage mode back-to-back of single pole, single pole list RRU merit divides two-way coverage mode.

Wherein, along the railway, urban district wherein or region, Plain, described base station adopts public network coverage mode; Suburb wherein or rural areas, described base station adopts public network or private network coverage mode; Mountain area wherein or hilly region, described base station adopts private network coverage mode.

Wherein, for railway the length of the process tunnel area that do not have wireless signal to cover at below 200m, adopt mode antenna being set in tunnel face tunnel interior orientation is launched;

For length be the tunnel of the moderate-length of 200m ~ 1000m and length more than the long tunnel of 1000m, adopt the coverage mode that RRU is combined with leakage cable;

For continuous tunnel, adopt directional antenna and leak the coverage mode that is combined of cable: adopt in tunnel and leak cable and cover, base station is set up in the centre in adjacent two tunnels, and employing directional antenna extends outwardly, and belongs to a community together in tunnel He outside tunnel.

Compared with prior art, beneficial effect of the present invention is: by carrying out the network planning of high ferro scene targetedly, operator can be helped to create the LTE overlay network of high-quality, decrease the harmful effect of train various factors in high speed movement, ensure that signal quality, improve user's experience.

Accompanying drawing explanation

Fig. 1 is base station and rail distance schematic diagram in the embodiment of the present invention;

Fig. 2 is the two RRU two-way covering scheme schematic diagram back-to-back of single pole in the embodiment of the present invention;

Fig. 3 is that in the embodiment of the present invention, single pole list RRU merit divides two-way covering scheme schematic diagram;

Fig. 4 is that in the embodiment of the present invention, high ferro private network covers adjacent section planning schematic diagram;

Fig. 5 is that in the embodiment of the present invention, tunnel leaks cable coverage distance estimation schematic diagram;

Fig. 6 is that embodiment of the present invention medium tunnel covers schematic diagram;

Fig. 7 is that in the embodiment of the present invention, single hole double track leakage cable lays schematic diagram;

Fig. 8 is that in the embodiment of the present invention, continuous tunnel covers schematic diagram.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

Propose a kind of LTE network plan of establishment being applicable to high ferro scene in the present embodiment, mainly comprise following aspect: base station selection, coverage mode, lectotype selection, networking mode, tunnel scheme.Describe in detail respectively below in conjunction with accompanying drawing.

(1) base station selection

Along with the reduction of incidence angle, railway car penetration loss increasing degree increases.When incidence angle θ is within 10 degree, train penetration loss amplitude is obviously accelerated, therefore when network design, and the incidence angle of suggestion employing more than 10 degree.

As shown in Figure 1, assuming that base station station spacing is S, H=S/2*tan θ, suggestion base station distance Along Railway vertical range D scope is (H, S/2).

As S=1100m, D=(97,550) m, namely advises that base station can be selected in from rail 97 ~ 550 meters of scopes.

High ferro base station selection should be interspersed in railway both sides as far as possible, in "the" shape cloth station, to help improvement is Zone switched and to be beneficial to both sides user acknowledge(ment) signal quality in compartment relatively uniform.For ") " or " (" shape bend corner region should select cloth station in turning, to help the impact reducing base station coverage direction and orbital direction angle reduction Doppler frequency shift.

(2) coverage mode

According to humanistic environment and the lineament of process in high ferro traveling process, the coverage mode suggestion for different scene is as follows:

Table 1 each scene high ferro coverage mode

Environment	Lineament	Suggestion coverage mode
			Urban district	Districts and cities are mild	Public network covers, and is equipped with and optimizes base station along the line
Suburb	Small towns is more	Public network or private network cover
			Rural area	Population distribution is wider	Public network or private network cover
Mountain area	Height above sea level margin is comparatively large, and with a varied topography, inclined-plane is steeper	Private network covers
			Hills	Mountain top shape is perfectly round, and Gu Kuanling is low, and inclined-plane is more slow	Private network covers
Plain	Ground broad flat or have slight relief	Public network covers, and is equipped with and optimizes base station along the line

(3) lectotype selection

1) antenna model selection

1. high-gain narrow beam antenna

In order to increase the coverage distance of single base station, reduce switching times, the suggestion of high ferro scene adopts the narrow lobe antenna of high-gain to cover.

High-gain narrow beam antenna is applicable to the fewer rural areas of periphery user, the more straight region of railway.

2. medium gain antenna

Be applicable to urban district, suburb, have station on the way, railway has the region of radian.

3. cable is leaked

Be applicable to tunnel scene.

2) base station type selecting

Distributed base station is applicable to the linear covering scene of high ferro: without the need to machine room resource, and BBU concentrates placement, is convenient to centralized management and safeguards, RRU fiber optic stretch, is convenient to fibre optic installations.

High ferro can adopt binary channels RRU to carry out covering networking, utilizes MIMO to promote network data service speed, adopts many RRU cell combining simultaneously, reduce handover between cells, thus promote network performance.Binary channels RRU networking can be divided into two RRU as shown in Figure 2, and two-way covering and single RRU merit as shown in Figure 3 divide two-way covering scheme back-to-back.

Binary channels RRU networking equipment volume is little, and convenient deployment, can realize MIMO in conjunction with dual-channel antenna; During multiple RRU cascade, cost-saving and reduce engineering construction difficulty.

1. RRU cascade network

In LTE system, the data communicated between BBU and RRU are I/Q data.I/Q data is carried on optical fiber to be transmitted, and therefore I/Q data bandwidth limits by Ir light mouth wire rate.Be 7 grades because Ir agreement limits maximum cascade number, and consider the constraint of practical application, capacity and reliability etc., suggestion RRU cascade number is no more than 4 grades.During cascaded RRUs, multiple RRU needs share I r bandwidth resources, and the increase of data volume significantly improves Ir interface data transmission rate requirement.

2. investment analysis

The investment of distributed base station list station is about 1.45 times of remote radio investment.Adopt RRU cascade network, about more than 20% can be reduced investment outlay.

(4) networking mode

The covering of high ferro can adopt public network or private network form.

1) public network networking

Dedicated network construction covers line of high-speed railway network to be solved with dedicated network, dedicated network with net greatly relatively independent, networking and planning need separately be done to consider, the later stage network optimization relatively simply, need consider with net greatly between be connected.Dedicated network construction is suitable for mountain area that high ferro need pass through, hills, suburb, rural area scene.

The adjacent section planning that a, high ferro private network and room, station are divided

Gate position AT STATION, high ferro private network website needs to divide mutual switching with room, station, and adjacent section planning need follow following principle:

1. interworking neighboring BS relationship is divided in high ferro private network and room, station

2. private network and a website room point switching position are tried not to drop on railway platform and to be got on or off the bus region

3. room, station is divided and public network interworking adjacent area

The adjacent section planning that b, high ferro are along the line

High ferro only needs to consider that on former and later two directions, chain community, Ge Yige community is as adjacent area on the section of run duration, with the adjacent section planning of public network, and the unidirectional adjacent area of proposed arrangement, as follows:

1. interworking adjacent area between private network in high railway line, ensures the successful switch of private network user in route minizone;

2. configure unidirectional adjacent area with periphery macro station, ensure that public network user is not switched to private network thus affects the capacity of private network.

High ferro private network covers adjacent section planning as shown in Figure 4.

(5) tunnel scheme

1) cable coverage distance is leaked

When train is at a high speed by tunnel, can form very large blast in tunnel, for ensureing that Signal reception in compartment is stablized and the traffic safety of train, suggestion adopts leakage cable to cover in the tunnel in.As shown in Figure 5, the coverage distance revealing cable is calculated as follows:

$D=\frac{\mathrm{Pin}-P-L1-L2-L3-L4-L5}{S}$

Wherein, P: leak cable input injecting power;

P: require to cover cell-edge;

L1: leak cable coupling loss, leaks cable index (95% probability)

L2: human body declines;

L3: width factor L3=20Lg (d/2), d is terminal and the distance of leaking cable in compartment;

L4: decay surplus;

L5: car body loss;

S: every meter leaks cable feeder loss.

It is as shown in the table that cable technical indicator is leaked in RFS producer:

Table 2 RFS reveals cable technology index

Frequency (MHz)

Loss/100m

Coupling loss (50%) dB

Coupling loss (95%) dB

	(20°)dB	(2m distance)	(2m distance)
				800	2.15	65	68
960	2.41	63	66
				1800	4.2	62	67
1900	4.53	60	65
				2200	5.79	60	65

According to the leakage cable technical indicator that RFS provides, reveal cable in tunnel and cover estimation as following table:

Leak cable in table 3 tunnel and cover estimation

Known, revealing the monolateral coverage distance of cable is 628m.Consider situation in Tunnel simultaneously, generally have a refuge chamber every 500m, reveal the monolateral covering 628m of cable, namely in tunnel, the installation site of RRU is every 1000m mono-substantially.Reveal cable can be laid in tunnel-side, height should be contour with train window, general recommendations distance rail level 2.1m ~ 2.6m.

2) switch band to arrange

The switching that LTE tunnel covers can be arranged on two regions: in tunnel and outside tunnel exit.Because tunnel face is narrow, cause the wireless signal outside tunnel to enter decay behind tunnel serious, if herein with signal switching in tunnel, handover success rate will be caused to reduce, cause speech quality to decline, even cause call drop.Usually at tunnel face place, directional antenna can be installed, signal in tunnel is extended to outside tunnel, switching band is arranged on outside tunnel exit.

For avoiding too much switching, usually adopting RRU to be total to the mode of community, covering a tunnel with the signal of same community.For the tunnel of speciality, a community is difficult to cover whole piece tunnel, now can arrange in tunnel and switch band.Need the overlapping coverage areas of the Liang Ge community arranging switching, the same macro station of its evaluation method, when estimation result is about 300km/h, in tunnel, overlapping coverage areas, minizone is about about 200m.

3) length/short tunnel covers scheme

1. short tunnel

For the tunnel that length does not have wireless signal to cover at below 200m, mode antenna being set in tunnel face tunnel interior orientation is launched can be adopted.Antenna should look logical whole tunnel as far as possible, switches band and is arranged on outside tunnel, wants to need the railway of covering and region to consider together around integrating tunnel simultaneously.

2. in, long tunnel

For length at the tunnel of the moderate-lengths such as 200 ~ 1000m and the length long tunnel more than 1000m, in tunnel, no signal covers, and suggestion adopts RRU+ to leak the coverage mode of cable, as shown in Figure 6.During as multiple RRU need be arranged, many RRU cell manner construction altogether should be adopted as far as possible, reduce switching times.

Leaking the height that cable installs answers apparent distance situation to arrange, the single-row or single hole double track of single hole but without the possible tunnel of meeting, leak cable and be laid in the tunnel wall of side, highly contour with train window; Single hole double track and may the tunnel of meeting, leaks cable and lays two row trains all visual logical leakage cable when height should ensure meeting.Single hole double track leaks cable and lays mode as shown in Figure 7.

3. continuous tunnel covers

As shown in Figure 8, for having multiple tunnel and the continuous tunnel that interval is very little each other, can consider to adopt the mode of directional antenna+leakage cable to cover: adopt in tunnel and reveal cable covering, base station is set up in the centre in two tunnels, employing directional antenna extends outwardly, belong to a community together in tunnel He outside tunnel, reduce and switch band.

The develop rapidly of China's high speed high ferro is with rapid changepl. never-ending changes and improvements, along with the arrival of information age, during traveller's, information transmission is whether unimpeded, be related to the service quality of mobile operator and the quality of traveller's environment, therefore the wireless coverage of public mobile communication system within the scope of road and rail is more outstanding.The present invention, by carrying out the network planning of high speed high ferro scene targetedly, can help operator to create the LTE overlay network of high-quality:

(1) impact of Doppler frequency shift on High-speed Circumstance is slight, complete correction of frequency errors by base station receiver and frequency deviation Rapid Variable Design is effectively compensated, but the impact of high ferro scene be can not ignore, suggestion adopts 1800M frequency range to carry out covering and advises that base station is selected in distance rail 97 ~ 550m scope, and station spacing is 1100 meters.

(2) decline is experienced by planning suitable overlapping region (suggestion high ferro private network scene overlap switches band and is set to about 200m) owing to switching the network caused fast, and adopt binary channels RRU to carry out networking covering, MIMO is utilized to promote network data service speed, adopt many RRU cell combining simultaneously, reduce handover between cells, thus promote network performance.

(3) for the tunnel scene of high ferro, the mode combined by leaking cable+RRU completes covering.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (7)

1. the method to set up of LTE network in high ferro environment, described LTE network comprises N number of base station and antenna, described N > 1; It is characterized in that, described base station is interspersed in railway both sides, in "the" shape cloth station; The incidence angle θ of described base station is not less than 10 degree; The scope of described base station distance Along Railway vertical range D is: S/2*tan θ < D < S/2, S is wherein base station station spacing, θ is minimum incidence angle.

2. the method to set up of LTE network in high ferro environment as claimed in claim 1, is characterized in that, in the method, for the base station of bend corner region being arranged at described railway, this base station is arranged in bend turning.

3. the method to set up of LTE network in high ferro environment as claimed in claim 1, is characterized in that, along the railway, the region that periphery user is few or railway is straight wherein, described antenna adopts high-gain narrow beam antenna; Urban district wherein, suburb, have station or railway to have the region of radian on the way, described antenna adopts medium gain antenna; Tunnel area wherein, described antenna adopts and leaks cable.

4. the method to set up of LTE network in high ferro environment as claimed in claim 1, it is characterized in that, described base station adopts binary channels RRU to cover networking mode.

5. the method to set up of LTE network in high ferro environment as claimed in claim 4, it is characterized in that, described binary channels RRU covers networking mode and comprises: the two RRU two-way coverage mode back-to-back of single pole, single pole list RRU merit divides two-way coverage mode.

6. the method to set up of LTE network in high ferro environment as claimed in claim 1, is characterized in that, along the railway, urban district wherein or region, Plain, described base station adopts public network coverage mode; Suburb wherein or rural areas, described base station adopts public network or private network coverage mode; Mountain area wherein or hilly region, described base station adopts private network coverage mode.

7. the method to set up of LTE network in high ferro environment as claimed in claim 3, is characterized in that, for railway the length of the process tunnel area that do not have wireless signal to cover at below 200m, adopt mode antenna being set in tunnel face tunnel interior orientation is launched;

For length be the tunnel of the moderate-length of 200m ~ 1000m and length more than the long tunnel of 1000m, adopt the coverage mode that RRU is combined with leakage cable;

For continuous tunnel, adopt directional antenna and leak the coverage mode that is combined of cable: adopt in tunnel and leak cable and cover, base station is set up in the centre in adjacent two tunnels, and employing directional antenna extends outwardly, and belongs to a community together in tunnel He outside tunnel.