What is GSM frequency conversion

Frequency rotation is a reasonable means of optimizing the network. After long-term capacity expansion and engineering construction, the network frequency is relatively chaotic. The existing network frequency is no longer suitable for continued use or the existing network is constantly being built, resulting in chaotic frequency resources and interference. At this time, the frequency of the entire network needs to be re-planned to make the frequency of the entire network more reasonable and achieve the purpose of optimizing indicators.

When the network is expanded in large quantities (including new sites and capacity expansion), the frequency reuse is too high, resulting in serious frequency interference. The frequency needs to be re-planned for the entire network. During the planning, the respective usage ranges of the main frequency and TCH are specified. At the same time, BSIC will also be planned at the same time to prevent the same frequency and BSIC from appearing. This is called frequency flipping, also known as frequency conversion.

Basically, frequency flipping is to re-plan the frequency.

Situations where frequency flipping is required:

1. Frequency confusion caused by the construction of new stations over a large area.

2. The wireless indicators are too poor and the frequency points are confused.

It is worth noting that frequency flipping does not cause any station outages, because the base station service outage time is relatively short. However, since it is necessary to verify whether the existing network will cause new problems after the frequency flipping, the frequency flipping time usually starts at 0:00 on Sunday. After completion, tests are immediately carried out to confirm the effect. Once a large-scale problem occurs, the data needs to be rolled back. Each equipment manufacturer and operator has certain judgment criteria.

Frequency flipping also has some risks. Before frequency flipping, the database should be backed up. If the frequency flipping fails, the original data can be imported back to avoid affecting the daytime network. In addition, after frequency flipping, the frequency flipping effect should be tested by DT to prevent network problems. Also, the billing system should be paid attention to. Don’t let the frequency flipping be completed, but the billing system has problems, which will be troublesome!

When the network is expanded in large quantities (including new sites and capacity expansion), the frequency reuse is too high, resulting in serious frequency interference. The frequency needs to be re-planned for the entire network. During the planning, the respective usage ranges of the main frequency and TCH are specified. At the same time, BSIC will also be planned at the same time to prevent the same frequency and BSIC from appearing. This is called frequency flipping, also known as frequency conversion.

Frequency conversion process:

Specifically, the frequency replanning process involves collecting network information and data, conducting network evaluation and analyzing problems with the original network frequency planning, forming a frequency replanning plan, and then using the U-net tool AFP module to make a detailed frequency planning plan. After review and modification, the plan is cut over and injected into the existing network, and optimization is performed immediately after the cutover to improve network performance.

1. Data collection and collation

A large amount of data needs to be collected before frequency rollover, in order to prepare the necessary data for frequency rollover and guide the formulation of the overall frequency rollover strategy. The data that needs to be collected include the working parameters of the existing network cells (the working parameters of the cells within the frequency rollover area and the cells outside the frequency rollover area), the top power of the cell, the relationship between the cell and the neighboring cells, the network optimization data, and the propagation model correction. The focus should be on the existing network super VIP, VIP sites, and areas. After collecting accurate data, it is necessary to organize, analyze and verify the data, and after the organization and analysis, you can roughly understand the distribution and configuration of the existing network sites.

2. Current network evaluation

On the one hand, network evaluation is to understand the operation status of the existing network and the defects in the original frequency planning. On the other hand, it serves as an acceptance standard for comparing the frequency conversion effects.

3. Frequency conversion plan

After having a certain understanding of the existing network, formulate a frequency rollover plan, divide the frequency rollover area, formulate the overall frequency planning principles, and implement relevant resources such as time, personnel, and tools;

4. Planning simulation

On the basis of preliminary sorting of the originally collected data, AFP import data is produced, and the data is imported into U-net for calculation. After the preliminary results are output, manual inspection is carried out, including simulation result verification, same frequency and BSIC inspection, frequency flipping area and peripheral frequency inspection, and after repeated inspection, it is submitted to the department for review;

5. Frequency switching

After the department reviews and modifies the frequency re-planning results, it submits the cutover data to the BSC data production personnel. After the database data is exported and checked to ensure that the data is correct, a cutover guarantee plan is formulated and the data is cutover and loaded into the existing network for operation;

6. Synchronous optimization

To ensure that there are no large-scale user complaints and index deterioration after the cutover, test verification and traffic statistics index analysis are carried out immediately after the cutover, network failures are handled in a timely manner, and the operation status of super VIP and VIP sites is paid special attention;

7. Frequency Flipping Effect Verification

After synchronization optimization, in order to compare the frequency flipping effect, the frequency flipping effect is demonstrated to meet user expectations through road testing, CQT testing, traffic statistics and other means.