Chapter 1 Radio Network Planning Process.pdf

CHAPTER 1: RADIO NETWORK PLANNING PROCESS 1.1 Radio Network Planning Process The network planning process itself is not standard. Though some of the steps may be common, the process is determined by the type of projects, criteria and targets. The process has to be applied case by case.

1.1.1 Network Planning Projects Network planning projects can be divided into three main categories based on how much external planning services the operator is using. No services means simply that the operator is responsible for the network planning from the very beginning until the end. This type of comprehensive responsibility for the network planning is more suitable for traditional network operators, who have extensive knowledge of their existing network and previous network planning experience than newcomers in this technology field. There is risk, however, that if the operator is the only person responsible for network planning there might be a difficulty in maintaining knowledge of the latest equipment and features. The opposite network planning solution is when the network operator buys the new network with a turnkey agreement (Greenfield case). In this case, the operator is involved only in defining the network planning criteria. After the network roll-out has been finished and enters the care phase an agreement about the future has to be made. The care services can be outsourced as well, but the operator might also be interested to take some portion of the network operations and start to learn the process. An operator taking all the responsibility after the outsourced planning phase includes some risk. A better solution is to learn the network operation at a pace agreed with the network vendor. The network operator can also buy network planning consultancy services. In this, the operator performs majority of the planning function and outsource selected aspects of the job. In this way some special know-how can be bought to supplement the knowledge of the network planning group. This is generally used in cases where new technologies need to be introduced in mature networks. The background of companies offering network planning services for operators is diverse. One group are the equipment vendors with the newest technical information about the equipment and technology. Another group are consultancy companies, who offer network planning services. These companies are independent from the vendors, which is on the one hand an advantage but on the other hand a disadvantage. When there needs to be selection between different vendors, the fair choice for cooperation is an independent consulting company. Network planning services are in some cases also offered by basic infrastructure firms, who are also involved in building the network.

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS

Figure 1.1 Network planning project organization

1.1.2 Network Planning Project Organisation The network planning project organisation is based on the network planning roll-out process steps. The final target of the network planning roll-out process is to deliver a new network for the operator according to the agreed requirements. The network planning project organisation is pictured according to network planning roll-out process flow in Figure 1.1. The roll-out process applies both for individual base stations as well as for the whole network. The process steps need to be phased and overlapped in order to keep the whole process inside a reasonable time limit. The network planning project management takes care of the whole project organisation. Some support functions, e.g. marketing, selling, logistics and technical support, are also project organisation wide and are not specifically connected to any of the project teams. ➢ The network planning team is responsible for both network preplanning and actual network planning, giving site proposals as the output. The network planning team has the assistance of the field measurement team. ➢ The site proposals are an input for the site acquisition team, which is responsible for finding the actual site locations. The site acquisition team makes technical site surveys ending up with site lease agreements for the best possible site locations – a decision that is always the sum of several factors. ➢ The construction works are carried out by the construction team and the target is to prepare the site ready for telecom implementation. The site location can vary from an existing building to a mast, which has to be built purposely. Therefore, the construction work varies a lot from one site to another. ➢ Telecom implementation covers installation, commissioning and integration. Installation is the setting up of the base station equipment, antennas and feeders.

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS ▪

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Commissioning stands for functional testing of stand-alone network entities. In the commissioning phase it is also verified that the site data depend on the network plan and, for example, the billing and routing data meet the operator requirements. The integration phase verifies that the site is operational as a part of the network. After this it is ready for commercial use. A separate optimisation team or the network planning team is responsible for the prelaunch optimization phase. Here the field test measurement team is giving support and the aim of this phase is to verify the functionality of the network. It should be shown that the parameter settings in the network are correct and that the planning targets can be met.

1.1.3 Network Planning Criteria and Targets Network planning is a complicated process consisting of several phases. The final target for the network planning process is to define the network design, which is then built as a cellular network. The network design can be an extension of the existing GSM network or a new network to be launched. The difficulty in network planning is to combine all of the requirements in an optimal way and to design a cost-effective network. Before the actual planning is started for a new network the current market situation is analysed. The market analysis covers all the competitors and the key information from them: market share, network coverage areas, services, tariffs, etc. Based on the market situation it is possible to create a future deployment strategy for the new operator. Questions arise about the nature of the targeted user group, how large is the coverage provided in the beginning and how it will grow in the future. It is also decided in the beginning what kind of services will be offered and which is connected to the target user group. This leads to estimations of market share at the beginning and objectives for the future. More detailed estimations are needed on how much each user of a certain type is using the services provided. The needed capacity for each service and onwards for the whole network can be calculated from the estimated average usage. The basic requirements for the cellular network are to meet coverage and quality targets. These requirements are also related to how the end user experiences the network. Coverage targets firstly mean the geographic area the network is covering with an agreed location probability, i.e. the probability to get service. The requirements also specify the signal strength values that need to be met inside different area types. The quality targets are related to factors such as the success of the call, the drop call ratio, which should not exceed the agreed value, and the success ratio for the call setup and for handovers. Environmental factors also greatly affect network planning. The propagation of radio waves varies depending on the area morphology (clutter type). The attenuation varies, for instance, when comparing rural, suburban and urban factors and also indoor and outdoor differences caused by buildings. Most importantly, the frequency range has an impact on propagation. The topography of the planned area, the location of cities, roads and other hotspots are obviously factors having an impact on planning. As the frequency band is a limited resource the available bandwidth partly determines the tactics for network planning. 3|Page

CHAPTER 1: RADIO NETWORK PLANNING PROCESS All previously mentioned factors, i.e. data based on market analysis, operator requirements, environmental factors and other boundary conditions, help to define planning parameters and frames for the network plan. Due to various design parameters the network planning process requires optimisation and compromises in order to end up with a functional cellular network. The network planning target is to build as high a quality network as possible. On the other hand, there is the cost-efficiency – how much money the operator can spend for the investments so that the business is financially profitable. The two factors i.e. network quality and investments are connected to profit. To simplify, the better the end users can be served and the more traffic the network can handle, the more impact there is on the profits. This explains the complexity of network planning, where sufficient cellular network coverage and capacity need to be created with as low investments as possible. A summary of the main factors affecting network planning are listed below: 1. Market analysis ▪ ▪ ▪

Competitor analysis Potential customers User profiles: services required and usage

2. Customer requirements ▪ ▪ ▪ ▪ ▪

Coverage requirements Capacity requirements Quality targets: call setup success, drop call rate, etc. Financial limitations Future deployment plans

3. Environment factors and other boundary conditions ▪ ▪ ▪ ▪ ▪

Clutter type Area topography Hotspot locations Available frequency band Recommended base transceiver station (BTS) locations

The radio network planning deliverables are final BTS configurations and site locations. The final coverage predictions including dominance and composite maps are delivered. Power budgets are calculated for all the configurations. Related to the frequency plan, the allocated frequencies are documented and an interference analysis is also presented. Deliverables also include the adjacency plan and allocated parameters, either default or optimized ones.

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS 1.2 Radio Network planning phases The main parameters i.e antenna type, antenna height, area type that affect radio network planning also define the radio propagation environment that specifies the characteristics of the radio propagation which furthermore has a significant effect on the coverage and capacity in the radio network. Radio network planning is a process that defines the stages i.e. visits in the area, measurements, planning, documentation required to provide a desired radio network plan for a certain geographical area. Moreover, the radio network planning process has to be defined carefully and carried out in different phases in order to manage the strong influences between: ▪ ▪ ▪

coverage capacity quality (interference probability)

These three areas must all be optimised in order to achieve a cost-efficient and overall high Quality of Service (containing good speech quality, minimum radio network congestion, minimum number of drop calls or handover failures) radio network. In coverage planning the aim is to maximise the base station coverage areas and thus minimise the required infrastructure. Correspondingly, the base station need has to be minimised in the capacity planning by reusing the frequencies as often as possible. These two topics have different applications: base station coverage area can be maximised by maximising the base station antenna height and the base station capacity can be maximised by maximising the frequency reuse that can be reached by minimising the base station antenna height. Furthermore, quality is not a real planning topic but is a very important “issue” and refers to primarily interference that can be connected to capacity and frequency planning that depend on coverage issues like the base station antenna heights. Quality connects radio network coverage and capacity planning and is related to frequency planning. This illustrates that any of these “topics” cannot be maximised but that they all have to be optimised in order to achieve a cost-efficient and high Quality of Service radio network. In order to plan good coverage while simultaneously optimising capacity and maximising quality, the radio network planning process and key areas for this process have to be clearly defined. Figure 1.2 presents the radio network planning process and its different phases which can be adapted to radio networks from commencement of deployment to their radio evolutionary extension. The same phases and studies are required time after time to deploy new and maintain existing networks. Three major radio network planning phases: ▪ ▪ ▪

dimensioning detailed radio network planning monitoring and optimisation

can be identified and each of these has a specific purpose. ➢ First, dimensioning is required to “generally” analyse the network configuration and to decide the radio network deployment strategy. 5|Page

CHAPTER 1: RADIO NETWORK PLANNING PROCESS ➢ Next, the radio network is accurately designed in the detailed radio system planning phase ➢ Finally, the radio network evolution requirements are considered in the optimisation and monitoring phase.

Figure 1.2: Radio Network planning phases Figure 1.2 shows that the three major radio network planning phases (dimensioning, detailed planning, monitoring and optimisation). Two parameters (traffic and coverage threshold) have a strong influence on the coverage, capacity and quality in the radio network and can thus be called “global.” These parameters define the basic required configuration that is related to base station antenna heights in the radio network. Traffic together with the available frequency band defines the number of base stations over a certain coverage area. Correspondingly, the coverage threshold defines the required number of base stations to cover the same area. By comparing these two results it can be shown whether the radio network planning is coverage or capacity driven oriented. When the theoretical base station quantity is studied, the average base station antenna height and also the average base station coverage area for the radio network can be defined. The average base station antenna height could be the third “global” parameter because it has the strongest individual influence on the base station coverage area and furthermore the strongest influence on the frequency reuse. Hence, traffic, coverage threshold and antenna height must be considered during network evolution.

1.2.1 Dimensioning Dimensioning is the first phase of the radio network planning process and its purpose is to initially draft the radio network configuration and deployment strategy for the long-term. This work could also be called a strategy of radio network planning because the aim is to define the essential radio parameter values and technologies in order to deploy the network. If the radio network is new there have to be several scenarios on how to exceed the coverage thresholds in different traffic situations. If an existing network is extended, the traffic history over the area has to be utilized to identify traffic increases during the next 1–3 years. The better the traffic forecasts the better the configuration (antenna heights and capacity) can be optimised for network evolution. The network planning criteria is used as an input for network dimensioning. Listed below are some basic inputs for dimensioning: ▪

size of the covered area

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS ▪ ▪ ▪ ▪ ▪ ▪

coverage requirements, the signal level for outdoor, in-car and indoor with the coverage probabilities quality requirements, drop call rate, call blocking frequency spectrum, number of channels, including information about possible needed guard bands subscriber information, number of users and growth figures traffic per user, busy hour value services.

Dimensioning gives a preliminary network plan as an output, which is then supplemented in coverage and parameter planning phases to create a more detailed plan. The preliminary plan includes the number of network elements that are needed to fulfil the quality of service requirements set by the operator, e.g. in GSM the number of BTSs and TRXs (transceivers). It also needs to be noted that dimensioning is repeated in the case of network extension. The result of dimensioning has two aspects; it tells the minimum number of base stations due to coverage or capacity reasons. Both of these aspects need to be analyzed against the original planning targets. It is also important to understand the forecasts for the subscriber growth and also the services that are going to be deployed. The dimensioning result is an average capacity requirement per area type like urban, suburban, etc. More detailed capacity planning, capacity allocation for individual cells, can be done using a planning tool having digital maps and traffic information. The dimensioning results are an input for coverage planning, which is the next step in the network planning process.

1.2.2 Detailed Planning Detailed radio planning is the second phase in the radio system planning process. After defining the average base station antenna height in the dimensioning phase (based on the traffic and coverage threshold requirements) , the required radio network finally has to be designed and implemented. Detailed radio planning i.e. coverage, capacity and frequency planning, has to be performed and documented. These three different planning phases are typically presented in discussion about the radio planning process. Noting the connection between coverage and capacity planning and the influence on base station configurations, the detailed planning process phases are (see also Figure 1.3): ▪ ▪ ▪ ▪

configuration planning coverage planning capacity and frequency planning parameter planning

Each of these phases are utilizing dimensioning results with the aim of designing a cost-efficient and high Quality of Service radio network in practice.

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS 1.2.2.1 Configuration planning Configuration planning must always occur in a specified area in order that traffic and coverage thresholds are exceeded. The area definition also needs to use a constant base station site configuration (e.g. macro sites and coverage driven configuration) as possible in the radio interface. These constant configurations make it easier to achieve the high-quality radio network and they also help, for example in logistics. Configuration planning is thus needed prior to coverage and capacity planning to analyse all available coverage and capacity related hardware and software features and single-, multi band equipment, to define features which are required at base station sites in different environments. Configuration planning analyses the capacity related system features and their influence on performance regarding the maximum number of frequencies at base stations. These capacity features and frequency assignments have a direct effect on the base station site equipment (e.g. narrowband or wideband combiners) which typically cause losses at the base station and in the antenna line. The base station site has to be configured based on both coverage and capacity requirements; the required capacity features define the capacity related base station site elements (combiners, etc.) and the required coverage or dominance area defines the need for other coverage related equipment (e.g. antenna gain, low noise amplifier (LNA), power amplifier (PA), diversity reception). The optimised base station configuration can finally be analyzed by calculating the power budget for the BTS–MS connection for the uplink and downlink directions. The above-mentioned capacity and coverage related equipment specifications can be taken into account in this power budget calculation and both coverage as well as capacity can be optimised. As a result of configuration planning the ▪ ▪ ▪

base station site type (macro, micro, indoor) base station antenna line (antenna height, single-, multi band) base station coverage/dominance (in other words service) area and capacity

for different areas and environments have to be defined. These three configuration parameters define the total base station site configuration that is to be used for a specific area in order to maximise the radio network cost efficiency and QOS. As only the final base station site locations may yet amend these configurations these can be clarified and confirmed in the detailed coverage planning. 1.2.2.2 Coverage Planning Configuration planning defines the base station site equipment for different environments (for coverage or capacity purposes). Coverage planning ultimately defines the radio network configuration. The aim of coverage planning is to utilise the dimensioning results (the average base station antenna height) and the configurations defined in the configuration planning (based on the power budget calculations) to minimise the number of base station sites. Thus, coverage planning has to be done over a certain area in order to be able to optimise the base station site locations and thus to utilise the base station configurations. The different phases of the coverage planning process are presented also in Figure 1.3 that shows the importance of the radio propagation measurements during radio coverage planning. Coverage planning begins with an 8|Page

CHAPTER 1: RADIO NETWORK PLANNING PROCESS open-minded coverage area survey which considers environmental limitations such as high buildings, hills or other obstacles. This survey indicates potential propagation problem areas and may already suggest some requirements for base station site locations. In this way this survey initially defines the critical base station site locations and suggests strategies to cover the area.

Figure 1.3: Coverage planning process Measurements are required to tune the radio propagation prediction model which is extremely important when considering capacity and frequency planning along with the functions of the radio network. Radio coverage planning is traditionally calculated in planning tools (advanced software programs) in the downlink direction from the base station transmitter to the mobile station antenna by defining the ▪ ▪ ▪

base station transmission power base station equipment and antenna line losses (combiner loss, cable loss) base station antenna height, direction, gain, and tilting if it is used.

The radio propagation prediction model is then checked once more and tuned, and finally the base station coverage area is calculated by using the input parameters, prediction model and digital maps. Typically, all these coverage planning phases are done in the radio planning tool, which provides a radio planning platform where the measurements can be imported, prediction models can be tuned and the coverage, capacity and frequency planning can be done. The target for the coverage planning phase is to find optimal locations for BSs to build continuous coverage according to the planning requirements. Coverage planning is performed with a planning tool including a digital map with topography and clutter type information and a tuned model for propagation. The propagation model tuning measurements have been performed with good accuracy. The last phase in coverage planning is to define the final coverage thresholds and the coverage areas where these thresholds have to be exceeded. The coverage planning thresholds can be defined based on the power budget and the coverage planning margins. These thresholds also finally define the average maximum distance between two base station sites.

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS 1.2.2.3 Capacity and Frequency planning Capacity and frequency planning are radio planning tool-based processes because the radio network configuration, as the number of frequencies used at each base station is already decided in the dimensioning phase and the aim is only to provide the best possible result by using the required configuration. Capacity and frequency planning start (or they have to be taken into account) when the base station sites are selected. The base station locations should be selected by trying to achieve equal base station coverage areas (and enough overlapping) and thus try to minimise interference in the radio network. Capacity and frequency planning begin by defining the planning thresholds, which depend on the hardware and software features used in the radio network. When the thresholds have been defined the rest of the capacity and frequency planning process is planning tool-based work at the onset of the radio network deployment. When the question is about the extension of a radio network a more detailed analysis is required to understand the actual capacity needs in the radio network. This analysis again has to be done over an area and based on the traffic measurements from the radio network. The total traffic has to be gathered from the specific area and the number of frequencies have to be calculated and compared to the actual configuration. In the capacity planning phase, the final coverage plan including composite and dominance information is combined with the user density information; in this way the capacity can be allocated. Boundary conditions for capacity allocation are agreed with the customer earlier, i.e. the maximum TRX number per base station. Planning tools have frequency planning algorithms for automatic frequency planning. These require parameter setting and prioritization for the parameters as an input for the iteration. The planning tool can also be utilised in manual frequency planning. The tool uses interference calculation algorithms and the target is to minimise firstly the co-channel interference and also to find as low adjacent channel interference as possible. Frequency planning is a critical phase in network planning as number of frequencies that can be used is always limited and therefore the task here is to find the best possible solution. 1.2.2.4 Parameter Planning Parameter planning is actually a very short phase before the launch of the radio network because the radio network parameter values are typically fixed and because their values are based on the measurements from the other networks and thus on precedence. Typically, parameters are divided into subgroups like: ▪ ▪ ▪ ▪ ▪

signaling radio resource management mobility management neighbour base station measurements handover and power control.

These parameters all concern and handle one type of function in the radio network. The parameter values are also quite fixed for the different environments but some small changes can be utilised, 10 | P a g e

CHAPTER 1: RADIO NETWORK PLANNING PROCESS e.g. for outdoor and indoor locations. Some special cases—like the dual band radio network and the traffic distribution between the frequency layers—need more detailed radio parameter analysis. The parameters themselves and the special cases are explained later because a detailed parameter planning is more connected to the optimisation process. The radio network parameters are also very powerful because they can be used for example for the prioritization of the base stations, as traffic can be distributed to a certain base station first and then others. After parameter planning the radio network is ready for operational mode and also ready to restart the same process— dimensioning and detailed planning—from the beginning due to radio network evolution. However, some statistics (from monitoring) are required from the network and some corrections (towards optimisation) can be done with the radio network before the radio network extensions need to start. In the parameter planning phase a recommended parameter setting is allocated for each network element. For radio planning the responsibility is to allocate parameters such as handover control and power control and define the location areas and set the parameters accordingly. In case advanced system features and services are in use care must be taken with parameter planning.

1.2.3 Verification and Acceptance After the planning phase has been finished the aim of the prelaunch optimisation phase is to ensure optimal operation of the network. In addition to fine-tuning, a search is made for possible mistakes that might have occurred during the installation. Prelaunch optimisation is high level optimisation but does not go into detail. Network optimisation continues after the launch and goes into a more detailed level. At that point the detailed level is easier to reach due to growing traffic. The quality of service requirements for the cellular network, i.e. coverage, capacity and quality requirements, are the basis for dimensioning. The targets are specified with key performance indicators (KPIs), which show the target to meet before network acceptance. Drive testing is used as the testing method for the network functionality verification. During the verification the functionality of different services agreed with the operator has to be tested. Table 1.1: Example coverage thresholds

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CHAPTER 1: RADIO NETWORK PLANNING PROCESS 1.2.4 Optimisation and monitoring The actual radio network planning process contained dimensioning, coverage, capacity and frequency planning and it would be perfect if the number of mobile stations and their locations were constant and already established in the radio planning phase. Unfortunately, neither the number of mobile stations nor their location is constant and thus there is no exact information about the configuration needs of the radio network before the network is up and running and some statistical data is gathered (monitoring). This statistical data indicates the final traffic in a certain area and it shows whether the radio network has overcapacity or congestion. The monitoring results (statistical data) are also a very important input for the dimensioning phase (for the network extensions) and thus a starting point for the network evolution. The optimisation process fits the designed radio network to the actual coverage demands and traffic. The first target is to verify the coverage and to analyse whether it is good enough. Next, the traffic over a certain area is studied and if the base station coverage area is overloaded (base stations are congested) it has to be analyzed whether: ▪ ▪ ▪

the traffic has to be balanced between the base stations or more frequencies have to be assigned or more base stations have to be implemented.

The optimisation phase is an adjustment process based on real life changes that were not taken into account in the original radio network planning, which was based on the coverage threshold requirements and traffic forecasts. Thus, both coverage and traffic verifications may trigger changes which influence back upon them. Moreover, the radio system planning process has to be repeated in the optimisation (optimisation = replanning) phase using the real information about coverage and traffic. When the actual coverage and capacity have been measured the optimisation work starts with an analysis of required base stations for traffic and continues with the coverage analysis, as in dimensioning. When the radio network configuration is defined, based on these real parameters, operational optimisation can be started. In this operational phase coverage may be improved by ▪ ▪

maximising the base station site configuration moving the base station sites.

Base station site capacities are directed at corresponding to the requirements by ▪ ▪ ▪

defining the actual need for frequencies at each base station location balancing the frequency assignments at each base station defining the required capacity-related software features to improve capacity.

When the base station coverage areas are satisfactory and the base station dominance areas correspond to the capacity requirements the radio network is balanced. After the network has been launched the planning and optimisation related activities do not end because network optimisation is a continuous process. For the optimisation the needed input is all available information about the network and its status. The network statistic figures, alarms and traffic itself are monitored carefully. Customer complaints are also a source of input to the network 12 | P a g e

CHAPTER 1: RADIO NETWORK PLANNING PROCESS optimisation team. The optimisation process includes both network level measurements and also field test measurements in order to analyse problem locations and also to indicate potential problems.

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