Thoughts on Wireless Network Simulation

In the construction of wireless networks, the three most important and urgent problems are coverage, capacity, and interference. Most of the work from initial network construction to engineering optimization is to solve the coverage and Interference Problems. The network will mainly solve the capacity and Interference Problems in the later stages of network development. With the deepening of network construction, operators have put forward higher requirements for refined network planning, rapid network construction, and network optimization. How to effectively solve these three problems becomes the key to improving the quality of network construction.

Based on years of wireless network construction experience, ZTE has proposed a new network hardware simulation system (NES) solution: during the planning and design stage, it uses a fixed receiver to simulate the base station, mobile transmitter analog terminals, each fixed receiver is equivalent to a cell of the base station to receive signals. Finally, the reverse road coverage effect after the implementation of the scheme is obtained, and the test results are applied to the wireless network planning and optimization, it is committed to solving coverage and Interference Problems in wireless networks and optimizing wireless parameters. Shows the NES Composition 1.

The spread model test application of NES and the whole network hard simulation application have been applied and popularized in the field, and the test efficiency and planning accuracy have been improved significantly. This article mainly discusses the expanded application of the test results.

The extended application of the NES results can be divided into the following three aspects:

◆ Display and adjustment of road coverage prediction results-greatly reducing the workload of engineering parameter adjustment after network construction;

◆ Eliminate pilot pollution-It plays a vital role in Engineering Optimization at the initial stage of wireless network construction;

◆ Optimization and adjustment of Wireless Parameters-mainly used to optimize the wireless parameters at the initial stage of network construction.

Road coverage Prediction

Figure 2 shows the test data and road coverage prediction results of the network-wide hardware simulation test in a city.

The data obtained from the NES test is the upstream data. After the loss is obtained from the upstream data, the actual PCCPCH transmit power, azimuth angle, downtilt angle, and station high computing pccpch rscp are combined with the current network design, the pccpch rscp after the road coverage prediction result is obtained. The result is based on the actual road coverage KPI obtained under the existing engineering parameters, this is equivalent to the road test result obtained before the network is created.

In this way, the pcccph rscp can be used to adjust engineering parameters based on the network construction indicators to obtain the optimal coverage results. The engineering parameters obtained based on the Road coverage prediction can be applied to the actual network, this greatly reduces the workload of engineering parameter adjustment after the network is built.

Adjustment of pilot pollution

In the actual network optimization process, when there are too many strong pilot signals, but there is not a strong enough dominant frequency signal, it is the pilot pollution. Generally, the PCCPCH has poor C/I performance in the pilot contaminated area, severe interference, and frequent ping-pong switching. Therefore, in the actual optimization process, after solving basic problems such as weak coverage, we need to solve the problem of pilot pollution.

Figure 3 shows the pilot pollution of the City Based on the NES test data and road coverage prediction results. There are 18 green points in the blue polygon of the pilot pollution points before the engineering parameter adjustment), use NES to predict and plan and obtain the parameter suggestions, after adjustment, the test shows two pilot contamination points, which eliminate most of the pilot pollution and obtain a more reasonable engineering parameter for engineering implementation.

Wireless parameter optimization Application

Based on the NES test data, adjacent areas, frequency points, and scrambling code can be optimized. That is, the adjacent areas with switching relationships can be found based on the overlap of test data points in each cell, add these adjacent areas to the list of existing adjacent areas, find the adjacent areas with the strongest interference with the main residential area and their frequency points, and optimize the frequency points to find the same-frequency and same-code residential areas with the strongest interference to the main residential area, optimize the scrambling code.

Optimization of neighboring areas, frequency points, and scrambling codes based on the NES test data. When there are not many users in the initial stage of network construction, so that the optimization of wireless parameters can give a reasonable neighboring area, frequency point, and scrambling code optimization scheme based on the actual signal distribution of each cell and the interference to other cells, which is of guiding significance.

The solution to the coverage optimization and coverage problems of wireless networks is the foundation and guarantee of the high-quality network pyramid. It solves the interference problems caused by coverage and coverage, it is a guarantee for sound network operations, smooth business development, and good user awareness in the future.

TD-SCDMA network has started the third phase of network construction, how to reduce the optimization work, shorten the optimization cycle, and ensure high-quality optimization results, to ensure coverage of KPI, ZTE has been working hard. Traditional Planning Simulation is limited to simulating the display and verification of indicators after the network is built under existing parameters. Under the guiding ideology of refined planning and optimization, the application of the network hardware simulation system (NES) is more concerned with the achievement of KPIs and the shortening of the network construction cycle, and provides solutions from all stages of the network. Network hardware simulation system (NES) is an in-depth thinking change for traditional planning simulation and optimization. This not only improves the efficiency and cost savings of equipment manufacturers, but also increases the time for operators and value transfer.