The method of WCDMA wireless network planning

With the development of 3G Mobile communication technology, 3G network planning has been mentioned in the agenda.

3G network planning includes not only wireless access network planning, but also the core network, transmission network, support system planning, integrated business platform development and many other aspects. 3G network planning is more complicated, in this paper, we mainly discuss some basic principles, planning process, content and methods of WCDMA wireless network planning.

The difference between WCDMA and 2G wireless network planning

Compared with the traditional 2G network, WCDMA Wireless network planning has the essential difference: the traditional 2G network has a relatively simple planning method because of its main business voice, but WCDMA network provides a rich and diverse business, which leads to WCDMA wireless network planning more complex than 2G.

The traditional 2G (GSM) wireless network planning can basically be divided into two steps: The first step is the prediction of the loss of wireless path, the purpose is to make the network guarantee the wireless coverage of the required business area; The second step is to determine the capacity of the system based on the estimation of the fields business volume. Usually in the wireless planning of GSM system, the main consideration is voice service and a small amount of data service (such as SMS service), so the capacity of the cell is a constant for the number of given channels. Therefore, in GSM wireless programming, the planning of coverage and capacity can be independently planned separately.

In WCDMA system, WCDMA system planning has many different contents than GSM system planning because it introduces many kinds of services including voice, different QoS, multi service environment and WCDMA system. In particular, in planning WCDMA systems, the coverage and capacity of the community should be combined with each other to consider. The coverage capability of WCDMA system is related to the system load condition, and the increase of system load will result in the reduction of coverage, the capacity of WCDMA per carrier is related to the environment and the interference of the area, and has the function of community respiration, namely "soft" characteristic. Therefore, in the WCDMA system, Power Control (TPC), soft switching and the gain generated by the softer switch, the power budget of the upper and lower links need to be considered.

The wireless network planning of GSM system is to obtain the best point between the capacity and coverage of the cell, while WCDMA wireless network planning should seek the best point between capacity, coverage and service quality, which increases the complexity of WCDMA wireless network planning virtually. (Computer science)

Second, the WCDMA Wireless network planning principles

Wireless network planning is based on the characteristics of the planned wireless network and the requirements of network planning, set the corresponding engineering parameters and wireless resource parameters, and to meet a certain signal coverage, system capacity and business quality requirements of the premise, so that the network's project cost is the lowest. Therefore, to plan a good wireless network, first of all need to understand the characteristics of wireless networks, such as the WCDMA network has a residential respiratory effect, with the increase in the community load, covering will gradually shrink; Secondly, we need to understand the operators of wireless network operating environment, wireless service requirements, different network operating environment, Different business requirements determine the performance metrics that different networks need to meet. With the above two conditions can start wireless network planning, in the WCDMA system network planning process, should follow the following basic planning principles.

1. The WCDMA network construction should adhere to the principle of scale development, and adopt the network planning and construction plan with the whole network unified planning and step-by-step implementation.

2. Network planning should be in the depth and breadth of coverage in accordance with the level of economic, infrastructure conditions and adjustment, in the economically developed, moderately developed areas and major cities to achieve the basic urban and county-level coverage, in less developed provinces and cities can achieve most of the coverage of prefecture-level cities.

3. With the further development of network, network planning should be covered in most towns in developed provinces, covering the majority of towns in the middle developed areas, which can be covered by a small number of townships in less developed areas, and finally achieve nationwide coverage.

4. Under the premise of reasonable technology, network planning should make full use of the existing communication infrastructure (including engine room, tower, transmission, etc.) to reduce the duplication of construction and reduce the cost of construction and operation.

5. We should choose reasonable technology and means, strengthen the wireless network planning, improve the comprehensive service quality, coordinate the relationship between wireless network capacity, wireless coverage and network quality and investment benefit, and ensure the comprehensive benefit of network construction.

6. Network planning should fully consider the long-term development goals, with good scalability, that is, the system capacity to meet the needs of user growth as a measure of the goal, can easily expand the upgrade to meet the long-term business needs.

7. Wireless network planning should combine coverage with business planning, taking into account both outdoor and indoor coverage.

8. Network planning to plan the construction of wireless support system, can provide different users of QoS level services.

Second, the WCDMA wireless network planning process

The process of WCDMA wireless network planning is basically the same as that of GSM network, and the main contents include defining planning objectives and information collection, planning, initial layout, site site survey and final design, as shown in Figure 1. According to the field survey results, the corresponding parameters are corrected before the final planning project enters the trial operation stage.

Figure 1WCDMA Wireless network planning process

Determining planning objectives and gathering information consists primarily of determining the areas to be covered by planning, the type of business supported by each zone, the coverage to be achieved for each business in each region, and so on. In addition, the collection of information also includes a variety of business volume density map, topographic data, carrier primary site information and network development long-term planning and other information. The planning objective should take into account market demand and cost factors comprehensively.

According to the information collected, the pre-planning process should comprehensively consider the requirements of coverage, capacity and quality, and obtain a preliminary design scheme of theoretical coverage and capacity planning, including establishing communication models and establishing link budget tables, evaluating customer sites and recommending new sites, and carrying out computer-aided network coverage and interference analysis.

Preliminary design is to be based on the specific circumstances of each region to develop a corresponding business volume planning and link budget, from the capacity and coverage of the estimation of base station quantity, the two balance, combined with the customer's primary site information, to obtain the initial layout of the base station.