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cBSS Network Planning Guideline

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cBSS Radio Network Planning

About This Chapter Radio network planning refers to planning the cBSS network according to the network construction target, network evolution requirements, cost requirements, types of optional equipment. Radio network planning specifies the number of NEs required by network construction, configuration parameters, and engineering parameters before the cBSS network construction. Radio network planning is directly related to the performances, construction costs, and maintenance costs of future networks. 1.1 Process of Radio Network Planning Radio network planning consists of two phases: preliminary radio network planning and final radio network planning. 1.2 Preliminary Radio Network Planning Preliminary radio network planning, conducted at the early stage of a project, is relatively rough compared with the final network planning. 1.3 Final Radio Network Planning Final radio network planning refers to performing field survey for each site based on the results of preliminary radio network planning and determining the engineering parameters of each cell. The cell planning and cell parameter settings can be simulated. Final radio network planning is conducted after preliminary radio network planning is complete and the commercial contract is entered. 1.4 Tools for Radio Network Planning The tools for radio network planning helps to collect and analyze data and thus assists radio network planning. The commonly used tools are CDMA RND tool, Genex U-Net, and Genex Apus.

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1.1 Process of Radio Network Planning Radio network planning consists of two phases: preliminary radio network planning and final radio network planning. 1.1.1 Procedure of Preliminary Radio Network Planning The preliminary radio network planning phase covers the following activities: information collection, area division, radio network dimensioning, propagation model selection, antenna selection, initial site selection, and system simulation. 1.1.2 Procedure of Final Radio Network Planning The final radio network planning phase covers the following activities: noise test, site survey and selection, system simulation, and cell parameter planning.

1.1.1 Procedure of Preliminary Radio Network Planning The preliminary radio network planning phase covers the following activities: information collection, area division, radio network dimensioning, propagation model selection, antenna selection, initial site selection, and system simulation. Figure 1-1 shows the procedure of preliminary radio network planning.

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Figure 1-1 Procedure of preliminary radio network planning

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Radio network dimensioning (RND), the first activity in the pre-planning phase, is conducted before the first round of bidding for a commercial network. Table 1-1 describes the tasks involved in preliminary radio network planning. Table 1-1 Tasks involved in preliminary radio network planning No.

Task

Description

1

Information collection

The collected information is used for the input of network planning or for reference.

2

Area Division

Radio propagation varies with areas. Generally, areas are classified into dense urban areas, urban areas, suburban areas, and rural areas.

3

RND

Coverage planning and capacity planning are performed.

4

Propagation model selection

Selecting the propagation model and determining the model parameters are performed.

5

Antenna selection

Appropriate antennas are selected based on the actual situations.

6

Initial site selection

l

Site survey (optional)

l

CW testing (optional)

l

Antenna selection

l

Parameter planning of the initial engineering parameters, such as azimuth angle and tilt angle

System simulation

7

Optional

NOTE

l

During the pre-sale planning phase, optional planning tasks can be omitted to ensure the planning progress.

l

During the post-sale planning phase, all planning tasks must be conducted to ensure accuracy.

1.1.2 Procedure of Final Radio Network Planning The final radio network planning phase covers the following activities: noise test, site survey and selection, system simulation, and cell parameter planning. Figure 1-2 shows the procedure of final radio network planning.

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Figure 1-2 Procedure of final radio network planning

Final radio network planning is detailed and specific planning on radio networks. Compared with preliminary network planning, final network planning differs only in the fact that system simulation, site survey and selection, and noise test are mandatory during final network planning but they are optional during preliminary network planning. Table 1-2 describes the tasks involved in network planning. Table 1-2 Tasks involved in final radio network planning No.

Task

Description

1

Noise test

Mandatory

2

Site survey and selection

If some sites are unqualified or inaccessible, define the Search Ring (by default, one fourth of the coverage radius) of the sites based on the preliminary network planning and re-select sites.

3

System simulation

Traffic distribution analysis

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Traffic model analysis

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No.

Task

Description

4

Cell parameter planning

Neighbor planning, PN planning, and system parameter planning

As shown in Figure 1-2, network planning is dynamic and cyclic. The whole process, from providing a specific requirement, to preparing the network planning scheme, and to a planning report, is cyclic and adjustable. For example, after system simulation, the previous network planning scheme can be improved, and then after the site survey and selection, the previous scheme can be further improved.

1.2 Preliminary Radio Network Planning Preliminary radio network planning, conducted at the early stage of a project, is relatively rough compared with the final network planning. 1.2.1 Input of Preliminary Radio Network Planning This describes the data and requirements to be collected before preliminary radio network planning. 1.2.2 Procedure of Preliminary Radio Network Planning The preliminary radio network planning phase covers the following activities: area division, radio network dimensioning, propagation model selection, antenna selection, site selection, and system simulation. 1.2.3 Output of Preliminary Radio Network Planning After the preliminary radio network planning is complete, the Nominal Radio Network Planning Report and the Radio Network Engineering Parameters Table should be provided.

1.2.1 Input of Preliminary Radio Network Planning This describes the data and requirements to be collected before preliminary radio network planning. Related information is collected in the initial phase of network planning. The collected information is used for network dimensioning, network simulation, and network construction policies. The collected information can be used for the input of network planning or for reference. Before network planning, the on-site owner needs to communicate with the customers or the persons from the Marketing Department to get aware of the network planning requirements. The on-site owner also needs to analyze expected planning output, destination information, network construction target, network scale limitation, and construction phase planning after the communication. The following information is required in the preliminary radio network planning phase:

1-6

l

Information provided by the Marketing Department, project documents before deployment, and destination information, such as population, area, and terrain

l

Requirements for network construction, including coverage service type, coverage, capacity, and quality requirements, if the contract is signed

l

Available sites and frequency, especially available sites of the initial network Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

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Exact scenario definition of the area to be planned

l

Propagation model corrected by the CW test

l

Digital map and software platform for network planning

If the existing network is expanded or migrated, the following information is required: recent network optimization report, configuration of the existing network, drive test documents of the existing network, traffic measurement data of the existing network, and customer complaints against the existing network.

1.2.2 Procedure of Preliminary Radio Network Planning The preliminary radio network planning phase covers the following activities: area division, radio network dimensioning, propagation model selection, antenna selection, site selection, and system simulation. 1.2.2.1 Area Division Area division is the first step in network planning. By performing area division, the target coverage area is divided into different sub-areas based on the radio propagation environments, coverage rates, and traffic distribution. 1.2.2.2 Radio Network Dimensioning Being an activity involved in preliminary radio network planning, the Radio Network Dimensioning (RND) refers to integrated dimensioning and planning of the numbers of BTSs and carriers required based on the results of coverage and capacity. The construction scale, construction period, economic cost, and manpower cost of the network can be planned according to the network dimensioning results. 1.2.2.3 Propagation Model Selection This describes how to select the propagation models and how to configure the related parameters. 1.2.2.4 Antenna Selection This describes how to select appropriate antennas for a target network coverage area. 1.2.2.5 Initial Site Selection This describes how to select appropriate sites and carry out site planning on the paper map or the electrical map according to the RND results, available site resources, coverage requirements, and analysis of the existing networks. The sites selected based on the theoretical calculation should conform to the ideal cellular network mesh structure. 1.2.2.6 System Simulation System simulation refers to performing Monte Carlo simulation based on the results of initial site selection and the traffic model. The simulation results are used to locate the radio coverage problem, and to check whether the network scale and the cell configuration meet the network construction requirements. Through adjusting site parameters, you can solve the radio coverage problem, and output engineering parameters for site construction, and cell parameters required by network construction.

Area Division Area division is the first step in network planning. By performing area division, the target coverage area is divided into different sub-areas based on the radio propagation environments, coverage rates, and traffic distribution. The target coverage area, however, generally does not have obviously marked sub-areas. In different sub-areas, such as urban areas and rural areas, the radio propagation environments, Issue 2.0 (2008-03-12)

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coverage rates, and traffic distribution are different. Thus, the quantity of BTSs differs in two areas with the same size. Generally, areas are divided into the following types: l

Dense urban areas

l

Urban areas

l

Suburban areas

l

Rural areas

Some special coverage areas can be divided into scenic spots, forests, grassland, or other types of terrain. Area scenario division directly affects network planning. Therefore, site survey at the early stage of network planning is necessary for the collection of information about the radio propagation environment. The results of site survey are the basis of scenario division. Table 1-3 describes the basis of area division. Table 1-3 Basis of area division Area Type

Description

Dense urban areas

Areas that have very dense population, prosperous economy, large traffic, comparatively dense and tall buildings in the center of a city, and shopping centers with full vitality

Urban areas

Areas that have less dense population, less prosperous economy, large call traffic, dense buildings in the center of a city, and shopping centers with vitality

Suburban areas

Areas that have moderate population, developing and promising economy, moderate traffic, less dense buildings in the center of an area, and shopping centers with a moderate scale

Rural areas

Areas that have small population, developing economy, and less traffic

Radio Network Dimensioning Being an activity involved in preliminary radio network planning, the Radio Network Dimensioning (RND) refers to integrated dimensioning and planning of the numbers of BTSs and carriers required based on the results of coverage and capacity. The construction scale, construction period, economic cost, and manpower cost of the network can be planned according to the network dimensioning results.

Input of RND Table 1-4 describes the input of RND.

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Table 1-4 Input of RND Input of RND Service type

Description Based on the requirements of network operators, determine the services that require continuous coverage. Therefore, the cell radius is estimated based on the service type, and the network is dimensioned based on the cell radius. Dense urban areas and urban areas have high requirement for the service rate of continuous coverage, and therefore the cell radius is relatively small. Suburban areas and rural areas have low requirements for the service rate of continuous coverage, and therefore the cell radius is relatively large. NOTE Services are classified into voice service and data services of different rates. Voice service and data service should be analyzed separately.

Cell target load

Traffic model

The cell target load, indicated by percentage, is determined by the network construction target. It is subject to the following factors: l

Uplink target load: If a low value is set, the dimension of the cell radius is large and fewer sites need to be planned. Therefore, the initial investment cost can be reduced. But when the number of subscribers increases, the radius of the cell is shortened, resulting in blind areas. For dense urban areas and urban areas, the uplink target load should be high enough to satisfy the requirements for capacity. For suburban areas and rural areas, the uplink target load can be relatively low to expand the network coverage and to reduce the initial investment cost. The typical value of the uplink target load is 50%–60%.

l

Downlink target load: The value of the target load can be set relatively high, because the actual value is relatively high. The typical value is 90%.

The traffic model is determined by service parameters. Service parameters refer to the traffic volumes of each service used by a single subscriber. l

For the voice service, the service volume of a single subscriber is indicated by traffic volume that is measured in Erl.

l

For the data service, the service volume of a single subscriber is indicated by busy hour throughput that is measured in bit/s.

The value of the service volume of a single subscriber must be set according to actual situations, such as local economic development, consumption habits, living habits, and the expenses on mobile communications. For the service volume of a single subscriber:

Number of subscribers

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l

If the value is set too high, more BTSs are required because the cell radius is very small. As a result, the initial investment cost is very high.

l

If the value is set too low, fewer BTSs are required because the cell radius is very large. As a result, the network capacity is so low that network expansion may be required shortly after the construction.

Refers to number of the mobile subscribers within the coverage of radio network services.

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Input of RND

Description

Propagation model

Used to predict the impact that terrain and human actions have on path loss. An appropriate model can ensure the accuracy of dimensioning. The propagation model is selected on the basis of scenarios and geographical environments.

Planning area

Areas within the coverage of radio signals. The size of this area is determined by the requirements of the operator.

Maximum number of available carriers every sector

Refers to the maximum number of available carriers in each sector of a BTS.

Related parameters of devices and terminals

Includes the transmit power, height of antennas, antenna gain, type of feeders, and length of feeders.

Target network quality

Refers to the coverage rate, system blocking rate, and frame error rate.

RND Coverage and capacity are considered during the RND phase, of which the procedure is described in Table 1-5 and shown in Figure 1-3. Table 1-5 Description of the RND procedure RND Process

Description

Obtain customer requirements for network construction. Get to know the objective and the policy of the network planning scheme by communicating with the marketing personnel.

-

Carry out capacity dimensioning of the Figure 1-4 shows the capacity dimensioning network configuration that meets the process. The number of required BTSs and the capacity requirement. number of required carriers are calculated according to the traffic model and the capacity that each type of BTS has. After capacity dimensioning, the CE configuration is required for each BTS. The detailed configuration of channel resources depends on BTS coverage and the number of subscribers that a BTS supports.

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RND Process

Description

Carry out the coverage dimensioning and calculate the site coverage radius according to the specific network capacity (CDMA network load) and customer requirements.

Figure 1-5 shows the coverage dimensioning process. During coverage dimensioning, the three should be taken into consideration: scenario type of the planning area, frequency scope, and network evaluation software. According to the principle of balancing between uplink and downlink, the maximum of allowed loss is calculated. The number of required BTSs can be calculated according to the coverage radius of a single site and the coverage area.

Calculate the number of BTSs and that of carriers required according to the coverage and capacity results. Evaluate network configuration that meets requirements of both the coverage and the capacity. Export the Huawei Radio Network Plan Proposal.

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Figure 1-3 RND procedure

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Figure 1-4 Capacity dimensioning

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Figure 1-5 Coverage dimensioning

Output of RND Table 1-6 describes the output of RND. Table 1-6 Output of RND Item

Output of RND

1

Results of the link budget, such as site scale of each scenario, cell radius, and required number of BTSs that meets the coverage requirement

2

Required number of BTSs, BTS type, and number of carriers

3

Results including site scale of each scenario, cell radius, system resource requirements, number of BTSs, site type, and number of carriers, to meet the coverage and capacity requirements

4

The Radio Network Dimensioning Report, which is used for future reference

Propagation Model Selection This describes how to select the propagation models and how to configure the related parameters. The propagation model selection phase consists of the following activities: 1-14

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Selecting propagation models Appropriate propagation models should be selected for different scenarios. The commonly used propagation models are Okumura-Hata and Cost231-Hata.

l

Configuring the related parameters Table 1-7 describes the methods of configuring propagation model parameters. Table 1-7 Methods of configuring propagation model parameters Method

Description

Propagation model calibration

This method is performed if the project time permits.

Referring to the similar model

The propagation model parameters are valued by referring to the calibrated model parameters in a similar radio environment. This method is commonly used in the phase of network dimensioning.

Antenna Selection This describes how to select appropriate antennas for a target network coverage area. The antenna functions as the interface between the radio transceiver and the outside propagation medium. One antenna can function as a receiver and a transmitter. Network coverage is achieved by means of the antenna, so the selection of antenna types has a direct impact on the coverage quality and interference control. The specifications of the antenna performance include the working band, gain, polarization mode, beamwidth, preset tilt angle, tilt method, tilt adjustment range, front-to-back suppression ratio, secondary lobe suppression ratio, and zero-point filling. The gain, horizontal beamwidth, and vertical beamwidth are interrelated according to the structure of the antenna. Table 1-8 describes the requirements for the antenna type selection in different scenarios. Table 1-8 Requirements for antenna selection in different scenarios Scenari o Dense urban areas Urban areas

Sector

Antenna Type Selection

3sectored

The antennas with bipolarization and 60 degrees to 65 degrees horizontal beamwidth are recommended. According to the BTS distribution and the building construction, the antennas with 13–16 dBi gains are recommended. The antennas with 10–12 dBi gains or lower in the micro-cell/ODU great hypsography situation can be selected. The preset tilt antennas (3–6 degrees recommended) or electrical tilt antennas are preferred. The zero-point filling can be ignored because the distance between sites in urban areas is small. In addition, the antenna support must be mechanically adjustable from 0–15 degrees.

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Scenari o

Sector

Antenna Type Selection

Suburban areas

3sectored

The antennas with 65 degrees or 90 degrees horizontal beamwidth are recommended. If the surrounding BTSs are densely distributed, refer to the antenna type selection in urban areas. If the surrounding BTSs are sparsely distributed and the possibility of future expansion is slight, refer to the antenna type selection in rural areas. Whether the antenna has a preset tilt angle depends on actual situations. Usually, the antenna has a very small preset electrical tilt or does not have any preset electrical tilt. Refer to the cases in urban areas and rural areas on the basis of the distance between sites.

Rural areas

3sectored

Vertical polarization and space diversity. The directional antennas with 90 degrees horizontal beamwidth and 16–18 dBi gain are recommended. The following antennas with different beamwidth are recommended for special areas: 210° heartshaped antennas at the mountainside, omni-directional antennas at the basin, and 8-shaped antennas at the valley. Typically, the mechanical tilt is recommended. The antenna without preset tilt angle is recommended. If the antenna is mounted more than 50 meters high and the near end coverage is required, set the zeropoint filling (more than 15%) to mandatory.

Rural areas

Omnidirectio nal

Vertical polarization and space diversity. The antennas with 11 dBi gain are recommended. If the required coverage distance is not long but the antenna is installed in a high position, the antennas with 3 degrees or degrees preset electrical tilt can be used. If the required height is less than 50 meters, ordinary antennas can be used.

When the 1X and 1xEV-DO networks are under co-site construction, there are two modes of antenna systems: sharing antenna system and not-sharing antenna system. Select the antenna system based on actual network resources for final network planning. The mode of sharing antenna system can save the space and the cost. But the two network systems may be mutually interfered, and certain loss is caused. Thus, forward and reverse coverage is affected. If 1X and 1xEV-DO networks do not share the antenna system, no loss is caused, and accordingly forward and reverse coverage is not affected. But a large space is required.

Initial Site Selection This describes how to select appropriate sites and carry out site planning on the paper map or the electrical map according to the RND results, available site resources, coverage requirements, and analysis of the existing networks. The sites selected based on the theoretical calculation should conform to the ideal cellular network mesh structure. The input information for initial site selection is listed as follows:

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l

Dimensioning results, including network scale of each scenario and cell radius

l

Available site resources Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

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Propagation model and antenna type

l

Mapinfo map or 3D digital map

l

Local regionalistic map (paper map)

Table 1-9 describes the process of the initial site selection. Table 1-9 Process of the initial site selection Item

Action

Description

1

Select or add a site

Before selecting the initial sites, you should have a good understanding of the terrain and buildings in the planning area to avoid selecting unnecessary or redundant sites. Site survey is optional in the preliminary network planning phase. The co-site construction of 1X and 1xEV-DO is recommended to avoid the near and far effect.

2

3

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Design the antenna azimuth angle.

Design the antenna tilt angle.

At the preliminary planning phase, consider the following two cases when setting the antenna azimuth angle: l

Set the initial azimuth angle with reference to the antenna tilt angle in the existing network if the co-site ratio is high in the preliminary planning phase.

l

Set the initial antenna direction with reference to the standard direction (clover-shaped) if the co-site ratio is low in the preliminary planning for the existing network or the emerging network. Slight adjustment can be allowed in a specific situation. The 3-sectored antenna azimuth angle must be consistent as possible in all BTSs in the city. Adjust the antenna azimuth angle in the direction of a key coverage area and adjust the major lobe in the direction of a heavy traffic area (rather than a straight street) for the interconnection of the urban area and the suburban area, trunk road, and single site in the rural area.

Consider the following two cases when setting the antenna tilt angle: l

For the existing network, set the initial tilt angle with reference to the antenna tilt angle in the existing network if the co-site ratio is high in the preliminary planning phase.

l

For the existing network or the emerging network, if the co-site ratio is low, set the tilt angle to degrees to degrees in the dense urban areas, to 2 degrees to degrees in the urban areas, and degrees to degrees in the suburban areas and rural areas.

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Item

Action

Description

4

Predict the coverage.

After the initial site selection, verify the quality of the network coverage through coverage dimensioning. Evaluate the coverage quality by observing the distribution of the pilot level and receiving level in the dimensioning results. l

For plots, adjust the antenna direction and the tilt angle if the coverage level does not satisfy the requirements.

l

For large areas where the coverage level does not satisfy the requirements, add sites to increase the coverage if the distance between sites is extremely far. If the distance between sites is not extremely far, check whether the setting of parameters for the coverage prediction is proper.

The output of initial site selection specifies the number of sites, site types, site locations (longitude and latitude), and engineering parameters of each site (antennal model, azimuth, tilt, and gain). The output is used for preliminary network planning.

System Simulation System simulation refers to performing Monte Carlo simulation based on the results of initial site selection and the traffic model. The simulation results are used to locate the radio coverage problem, and to check whether the network scale and the cell configuration meet the network construction requirements. Through adjusting site parameters, you can solve the radio coverage problem, and output engineering parameters for site construction, and cell parameters required by network construction. The system simulation process in the preliminary planning phase is the same as that in the final planning phase. The differences between the preliminary planning phase and the final planning phase are as follows: l

In the preliminary planning phase, as the time and the cost are limited, a site does not go through a field survey. The site is not available unless it is confirmed by the customer. Therefore, the estimated values of engineering parameters are used in the preliminary planning phase.

l

In the final planning phase, each site goes through field survey and should be confirmed as available. The engineering parameters must be confirmed. For example, the type and the length of feeders must conform to the actual requirements. If the system simulation results in the final planning phase do not meet the requirements, it is difficult to take corrective measures, if required.

Input and Output of System Simulation Table 1-10 describes the input of the system simulation phase. After system simulation, the System Simulation Report should be provided.

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Table 1-10 Input of system simulation Item

Input

1

Engineering parameters table

2

Propagation model

3

Scenarios, channel types, service types, traffic model, antenna parameters, and network parameters

4

Simulation software and digital electric map

Procedure of Simulation System simulation refers to using planning simulation software and simulating the actual network environment to achieve network coverage and QoS prediction. When the initial site selection and pilot coverage prediction satisfy the requirements, the system simulation conducts the Monte Carlo simulation according to the corresponding service type, traffic model, number of subscribers, and subscriber distribution. Usually, the system simulation takes a long time. Locate the problematic areas through system simulation. Export engineering parameters and cell parameters by adjusting the sites or taking other measures to satisfy the requirements of site construction. Figure 1-6 shows the simulation process by illustrating Huawei network planning software UNET.

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Figure 1-6 Simulation procedure of preliminary radio network planning

Different from a simple network coverage prediction, the simulation focuses on the detailed analysis of the traffic model, subscriber behavior, and subscriber distribution in the network. These parameters are closely related to network capacity. The analysis of simulation results focuses on coverage prediction and Monte Carlo simulation so that you can check whether the RX and the Ec/Io satisfy the requirements. In addition, the simulation results also concern the access success ratio, pilot pollution, soft handoff ratio, uplink and downlink load analysis, and the access failure from which the causes and solutions can be found out. Through the analysis of simulation results, you can determine whether the network scale and cell configuration achieve the network construction objective.

1.2.3 Output of Preliminary Radio Network Planning After the preliminary radio network planning is complete, the Nominal Radio Network Planning Report and the Radio Network Engineering Parameters Table should be provided. Table 1-11 describes the output of preliminary radio network planning. 1-20

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Table 1-11 Output of preliminary radio network planning Output Report

Topic

Nominal Radio Network Planning Report

l

Network construction policy

l

Initial site planning

l

Suggestions for antenna selection

l

Simulation result evaluation

l

Number of BTSs

l

Site location

l

Antenna type, azimuth angle, and tilt angle

l

Cell parameters, such as channel power and soft handoff parameters

Radio Network Engineering Parameters Table

1.3 Final Radio Network Planning Final radio network planning refers to performing field survey for each site based on the results of preliminary radio network planning and determining the engineering parameters of each cell. The cell planning and cell parameter settings can be simulated. Final radio network planning is conducted after preliminary radio network planning is complete and the commercial contract is entered. 1.3.1 Input of Final Radio Network Planning This describes the input of final radio network planning, that is, the output of preliminary radio network planning and the contract information. 1.3.2 Procedure of Final Radio Network Planning The final radio network planning phase involves the following activities: noise test, site survey and selection, system simulation, and cell parameter planning. 1.3.3 Output of Final Radio Network Planning This describes the output of final radio network planning. The output, including the information on BTS planning and the information on radio parameter planning, is presented in the Radio Network Planning Report, Radio Network Planning Engineering Parameters Table, and Radio Network Planning Cell Parameters Table.

1.3.1 Input of Final Radio Network Planning This describes the input of final radio network planning, that is, the output of preliminary radio network planning and the contract information. The required input of final radio network planning is as follows: l

Nominal Radio Network Planning Report

l

Radio network engineering parameters table

l

Requirements defined in the contract

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1.3.2 Procedure of Final Radio Network Planning The final radio network planning phase involves the following activities: noise test, site survey and selection, system simulation, and cell parameter planning. 1.3.2.1 Noise Test A noise test is performed to check the interference and noises in the operating band, and thus appropriate measures can be taken to ensure smooth running of the network. 1.3.2.2 Site Survey and Selection Site survey and selection are important during network planning. You can carry out a site survey for the candidate sites or the candidate site areas. 1.3.2.3 System Simulation System simulation refers to performing Monte Carlo simulation based on the results of initial site selection and the traffic model. The simulation results are used to locate the radio coverage problem, and to check whether the network scale and the cell configuration meet the network construction requirements. Through adjusting site parameters, you can solve the radio coverage problem, and output engineering parameters for site construction, and cell parameters required by network construction. 1.3.2.4 Cell Parameter Planning After specifying the size, BTS configuration, and BTS location of a network, interconnect detailed cell parameter planning with all BTSs and cells.

Noise Test A noise test is performed to check the interference and noises in the operating band, and thus appropriate measures can be taken to ensure smooth running of the network. The noise test is optional, because the electromagnetic environment of each band is different. If required, on-site noise test must be performed by using an electric logging device or a YBT250 tool. If strong noise interference exists over a frequency band, you must clear the noise or apply for new frequencies. In the phase of site selection, you must conduct noise tests in the areas that have heavy traffic or important landmarks to ensure that strong noise interference does not and will not exist. In this way, the network performance is guaranteed. After a noise test is complete, the Noise Test Report should be provided for future reference.

Site Survey and Selection Site survey and selection are important during network planning. You can carry out a site survey for the candidate sites or the candidate site areas. Survey tools and personnel cooperation: a GPS and a compass The project designers and the engineers of the operator should participate in the site survey. For each recommended site, collect network planning information and environment information to confirm that the site meets the construction requirements. The information required for a site survey is as follows: l

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condition, power condition, grounding condition of the equipment room, business consideration (possibility of renting a site location or rent cost) l

Environment information: type and distribution of the typical propagation environment, average height of buildings, plant distribution (type, height, and density), location of the coverage target, description of the adjacent environment

l

In the case of co-site construction, you must consider available resources for the equipment room and the platform, antenna isolation, possible effect, and preventive measures.

If the survey results of a site meet the construction requirements, the site can be selected. From the aspects of height, antenna space availability, and equipment room availability, you can conduct a simple survey and select one or two candidate sites. After the final site is confirmed, the Site Survey Report should be provided. The site survey report includes survey records of all sites, detailed description of the related items, subsequent preparations, and selected sites.

System Simulation System simulation refers to performing Monte Carlo simulation based on the results of initial site selection and the traffic model. The simulation results are used to locate the radio coverage problem, and to check whether the network scale and the cell configuration meet the network construction requirements. Through adjusting site parameters, you can solve the radio coverage problem, and output engineering parameters for site construction, and cell parameters required by network construction. The system simulation process in the preliminary planning phase is the same as that in the final planning phase. The differences between the preliminary planning phase and the final planning phase are as follows: l

In the preliminary planning phase, as the time and the cost are limited, a site does not go through a field survey. The site is not available unless it is confirmed by the customer. Therefore, the estimated values of engineering parameters are used in the preliminary planning phase.

l

In the final planning phase, each site goes through field survey and should be confirmed as available. The engineering parameters must be confirmed. For example, the type and the length of feeders must conform to the actual requirements. If the system simulation results in the final planning phase do not meet the requirements, it is difficult to take corrective measures, if required.

Input and Output of System Simulation Table 1-13 describes the input of the system simulation phase. After system simulation, the System Simulation Report should be provided. Table 1-12 Input of system simulation Item

Input

1

Engineering parameters table

2

Propagation model

3

Scenarios, channel types, service types, traffic model, antenna parameters, and network parameters

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Item

Input

4

Simulation software and digital electric map

Procedure of Simulation System simulation refers to using planning simulation software and simulating the actual network environment to achieve network coverage and QoS prediction. When the initial site selection and pilot coverage prediction satisfy the requirements, the system simulation conducts the Monte Carlo simulation according to the corresponding service type, traffic model, number of subscribers, and subscriber distribution. Usually, the system simulation takes a long time. Locate the problematic areas through system simulation. Export engineering parameters and cell parameters by adjusting the sites or taking other measures to satisfy the requirements of site construction. Figure 1-7 shows the simulation process by illustrating Huawei network planning software UNET.

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Figure 1-7 Simulation procedure of preliminary radio network planning

Different from a simple network coverage prediction, the simulation focuses on the detailed analysis of the traffic model, subscriber behavior, and subscriber distribution in the network. These parameters are closely related to network capacity. The analysis of simulation results focuses on coverage prediction and Monte Carlo simulation so that you can check whether the RX and the Ec/Io satisfy the requirements. In addition, the simulation results also concern the access success ratio, pilot pollution, soft handoff ratio, uplink and downlink load analysis, and the access failure from which the causes and solutions can be found out. Through the analysis of simulation results, you can determine whether the network scale and cell configuration achieve the network construction objective.

Cell Parameter Planning After specifying the size, BTS configuration, and BTS location of a network, interconnect detailed cell parameter planning with all BTSs and cells. Issue 2.0 (2008-03-12)

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Cell parameters vary slightly with network types. Table 1-13 describes the cell parameters and planning methods. Table 1-13 Cell parameters and planning methods Cell Parameter

Planning Method

Location area planning

NOTE This parameter is planned for the 1X system only.

Neighboring cell list (intrafrequency neighboring cell, interfrequency neighboring cell, and intersystem neighboring cell)

PN code

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l

The value of the LAC cannot be set extremely large. The maximum value of the LAC depends on the paging channel capacity and processing capability of the BSC.

l

The value of the REG_ZONE cannot be set extremely small. The minimum value of the REG_ZONE depends on the access channel capacity.

l

The LAC planning should comply with the geographical position and the action of MSs so that the border of a location area is not updated.

l

A location area cannot cross multiple MSC areas. The location area that crosses multiple BSC areas is not recommended.

l

In the case of multiple carriers, the carriers in one sector should be in the same location area.

l

Places with heavy traffic should not be in the border of a location area.

l

Neighboring cells should be firstly configured for the sectors in the local BTS.

l

The geographically adjacent cells should be configured to neighboring cells.

l

Neighboring cells should be mutually related. In some special situations, a single neighboring cell is required.

l

In dense urban areas and urban areas, necessary neighboring cells should be configured, and on the other hand, excessive neighboring cells should be avoided.

l

In suburban areas, the geographically adjacent cells should be configured to neighboring cells to ensure timely handoff and to avoid call drop.

l

The neighboring cells with the strongest signals should be arranged in the front of the neighboring cell list to avoid interference.

l

The hard handoff of neighboring cells should be carried out in the places with light traffic as possible.

l

Phases between different pilots should be arranged at intervals. When the pilots with different PN offset of other sectors appear in the Active Searching window of the current sector, the interference to the current sector should be lower than the preset threshold.

l

For the PN multiplexing distance between two BTSs with the same pilot, the interference that other sectors with the same PN offset cause to the current sector should be lower than the preset threshold.

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Cell Parameter

Planning Method

Cell channel power matching

Power distribution proportion of common channels (such as pilot channel, synchronization channel, and paging channel) and traffic channels.

Handoff parameter planning and access parameter planning

You must set the values of these parameters according to the actual network situations.

Color code

NOTE This parameter is planned for the 1xEV-DO system only.

Subnet

l

The color codes should vary with the subnets in the access network (AN).

l

The color codes corresponding to the subnets in an adjacent AN should be different from the color codes corresponding to the subnets in the AN.

l

The color codes corresponding to the subnets in one city (including the suburban areas) should be different. The color codes corresponding to the subnets in different cities (including the suburban areas) can be multiplexed.

NOTE This parameter is planned for the 1xEV-DO system only. l

The entire network should be planned globally. The subnet locations should be unique in the entire network. Different operators are assigned different network segments.

l

The value of a subnet cannot be set extremely large. The maximum value of a subnet depends on the CC channel capacity. The value of a subnet cannot be set extremely small. The minimum value of a subnet depends on the AC channel capacity. The calculation of the CC channel capacity and the AC channel capacity is omplex. You can get the calculation results from simulation results. Usually, one subnet is configured for an AN.

l

The subnet planning should comply with the geographical position and the action of MSs. This can reduce the location updates of MSs at the border of a subnet.

l

A subnet cannot cross multiple ANs.

1.3.3 Output of Final Radio Network Planning This describes the output of final radio network planning. The output, including the information on BTS planning and the information on radio parameter planning, is presented in the Radio Network Planning Report, Radio Network Planning Engineering Parameters Table, and Radio Network Planning Cell Parameters Table. Table 1-14 describes the output of final radio network planning. Issue 2.0 (2008-03-12)

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Table 1-14 Output of final radio network planning Output

Description

Information on radio network BTS planning

l

Site information

l

Design of the antenna system

l

Selection of the BTS equipment type

l

PN planning

l

Neighboring cell planning

l

Location area planning

l

1xEV-DO color code planning

l

1xEV-DO subnet planning

l

Planning of the system parameters, such as power parameters, switching parameters, and access parameters

Information on radio parameter planning

After the final radio network planning is complete, the Radio Network Planning Report, Radio Network Planning Engineering Parameters Table, and Radio Network Planning Cell Parameters Table should be provided. Table 1-15 describes the topics of the reports. Table 1-15 Output reports of final radio network planning Output Report

Topic

Radio Network Planning Report

l

Network construction policies in different phases

l

BTS planning

l

Cell parameter planning

l

Analysis of the simulation results

l

Solutions to coverage capacity in special scenarios

l

Required number of CEs in each site

l

Number, name, longitude and latitude of the BTS

l

Sector name, cell ID, and cell name

l

TRX ID and frequency

l

LAC, RAC, and PN code

l

Color code and subnet (1xEV-DO)

l

Antenna type, polarization mode, horizontal and vertical half power angle, and gain

l

Height, azimuth angle, and azimuth angle of the antenna

l

Power amplifier type, and combining and dividing mode

l

Type and length of the feeder

l

Cell coverage target

Radio Network Planning Engineering Parameters Table

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Output Report

Topic

Radio Network Planning Cell Parameters Table

l

LAC/REG-ZONE configuration

l

Neighboring cell configuration

l

Frequency and PN code

l

Color code and subnet (1xEV-DO)

l

System parameters, such as power parameters, switching parameters, and access parameters

1.4 Tools for Radio Network Planning The tools for radio network planning helps to collect and analyze data and thus assists radio network planning. The commonly used tools are CDMA RND tool, Genex U-Net, and Genex Apus.

CDMA RND Tool The RND tool, which is independently developed by Huawei, is a network dimensioning tool based on cumulative experiences of the RND. The tool is one of the important tools for preliminary network planning. With the iterative algorithm, the RND tool achieves the balance between the network coverage and the capacity, and accordingly simplifies network dimensioning. The functional modules of the RND tool are link budget, capacity budget, traffic model building, budget of the number of BTSs, and CE configuration budget. The tool can calculate the following dimensioning results based on the existing and preset relevant data: l

Required number of BTSs that meet the coverage and capacity requirements

l

Coverage and capacity limitation

l

CE limitation

l

Throughput of the entire network, such as total forward throughput and total reserve throughput

l

Required number of BTSs that meet the coverage requirements

l

Forward and reverse coverage limitation

l

Coverage radius and coverage area of a single BTS

l

Required number of BTSs that meet the capacity requirements

l

Forward and reverse capacity limitation

Genex U-Net The Genex U-Net, which is independently developed by Huawei, is a tool of radio network planning. Running on the Windows 2000 and Windows XP operating systems, the Genex UNet supports 2G and 3G technologies and supports incumbent networks such as GSM/TDMA, GPRS-EDGE, WCDMA, and CDMA. In addition, it has the advantages of flexible user interface and easy operation. Issue 2.0 (2008-03-12)

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Being a kind of simulation software of radio network planning, the Genex U-Net provides the global support for initial network design, dense network planning construction, and network optimization. The Genex U-Net has the following applications: l

Used before the network construction. The Genex U-Net is used for nominal network planning, model calibration, prediction and simulation, and site analysis to ensure good effect of the network construction.

l

Used in network construction and expansion. The Genex U-Net performs parameter planning and simulation. In addition, this tool can analyze the network coverage and performance under different parameter configurations. In this way, reasonable parameters can be configured to ensure optimal network performance.

l

Used in network optimization. The Genex U-Net is used for network adjustment and optimization.

Functions of the Genex U-Net are as follows: l

Network construction and radio parameter model construction

l

Traffic modelling and capacity prediction

l

CDMA simulation based on the Monte-Carlo (supporting 1xRTT and 1xEV-DO)

l

CDMA coverage prediction (supporting 1xRTT and 1xEV-DO)

l

Statistic analysis

Other functions of the Genex U-Net l

Automatic planning for neighboring cells

l

Automatic PN planning and PN multiplexing checking

l

Propagation model calibration

Genex Apus The Genex Apus, which is independently developed by Huawei, is a kind of Genex software. The Genex Apus is used in the network planning phase. The main functions are neighboring cell planning and PN planning. The Genex Apus has two modules: neighboring cell planning and PN planning. The module of neighboring cell planning implements automatic neighboring cell planning. The module of PN planning implements automatic planning for PN codes. The following describes the two functions on the whole. l

Neighboring cell planning Based on the BTS sector topology and radio parameters (such as the latitude and longitude, azimuth angle, and tilt angle, height of the antenna, and transmit power) related to the network sectors, the module can set multiple radio propagation models, and implement neighboring cell planning for the CDMA network.

l

PN planning Based on the BTS topology, the module implements automatic planning for PN codes.

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