WCDMA wireless network optimization and test)

Preface Third-generation mobile communication technology not only brings a wide range of business types, a higher speed, but also brings complexity of network planning and optimization. How to evaluate and measure whether the network performance meets the design requirements, and how to plan and optimize a network in the best way requires not only technology, but also tools to help. Road testing is an important means of network optimization. It directly measures and evaluates network conditions and network performance indicators, and points out network problems. At present, Huawei has achieved good application by using its self-developed road test system and background analysis system for network optimization. This article first introduces the function of the network optimization Middle test, and secondly introduces the features and application examples of the road test tool genex probe. Role of road test in Network Optimization 1. Content and parameters of the road test 3G network optimization involves multiple aspects. You need to analyze the network performance data and the optimization test at the same time. At the initial stage of network construction, it is the most important to use the road test to understand the network conditions. The road test data includes the strength and quality of the district guide, and the data reported by the mobile phone during reselection, access, and connection. Through analysis, the final report on diagnosing network problems and reflecting network performance is generated. The test parameters generally include the pilot coverage test, switching indicator, data service performance test, and business function test. During the test, the following Wireless Parameters and devices are usually collected: Table 1 basic content of WCDMA road test collection Parameter type Parameter Details Collection Device Pilot EC, EC/Io, SC Road frequency tester, mobile phone Testing Power TX, RX, (UL/dl) TPC Test mobile phone Receiving Quality Sir, Sir target, BLER Test mobile phone Throughput (UL/dl) app throughput, RLC Throughput Test mobile phone Signaling MAC/RLC, RRC, NAS Receive and parse system messages such as mobile phones and some Scanners Network Parameters and cell parameters Active Set, monitor set PILOT: EC, EC/Io, PSC, frequency MCC, MNC, LAC, cellid GMM state, MM state, SM state Mobile phone test, road test Scanner Carriers with GSM usually use testing tools to collect GSM network parameters and orders as necessary for use and purchase. 2. Components of the Road Test System Take the genex probe road test system as an example. The general structure of the road test system is as follows: Structure of Road Test System 2.1 WCDMA frequency scanner Genex probe is connected to a high-speed frequency scanner. Its main test indicators are: The first n pieces of cell guide signal strength on one or more of the pilot frequencies (n can reach up to 32) Test the disturbance code strength of a specified Guide Spectrum Analysis on network bandwidth Receive intensity on WCDMA Carrier The continuous wave signal strength and sampling rate meet Lee's law. 2.2 WCDMA/GSM dual-mode test mobile phone The road test system uses the mobile phone for data sampling. The test mobile phone communicates with the computer and the test software through data lines or other connections, and obtains data through control of the mobile phone. Test mobile phones should generally report complete wireless network parameters, including signaling information. In addition, mobile phones must have complete capabilities such as VP, stream service, Amr, 3g/2G reselection and switching, and abnormal frequency switching. To meet the needs of network testing. GPS 2.3 GPS is mainly used to report geographic location data. This allows you to perform geographic analysis on network test data. Common GPS include Garmin and Trimble. Some regions also have built-in GPS modules and do not need to be purchased separately. Network Optimization Using genex Probe Test System A well-planned network lays the foundation for smooth optimization. Once the network planning is completed, optimization becomes a long-term task. Network Optimization Using road tests is based on data collection of tracing and UE, data analysis and processing in the background, and network engineering parameters, so as to provide optimization suggestions and reports. Basically all communication equipment manufacturers, wireless network operators and third-party optimization vendors must have a road test system to complete network optimization. The following is an example of the application of the road test system in wireless network optimization. 1. Scanning Measurement and Optimization In the optimization process, testing mobile phones and tokens is essential. Mobile phones can perform signaling, protocol, and service performance tests. However, it is controlled by the network. The WCDMA frequency scanner can fully and objectively reflect the complete signal distribution and RF status. First, in the initial stage of network planning, genex probe will test the communication environment in the planned area, that is, CW testing. 1.1 CW Test This method can be used to conduct a general survey of the propagation environment and correct the propagation model: CW test diagram The test data can be geographically averaged to filter out bad points, and then imported into the unet network planning tool for propagation model correction. 1.2 boot coverage test It is used for analysis of pilot coverage, soft switch zone analysis, and assistance in locating dropped calls. You can perform soft switchover simulation on the genex assistant data processing background, and locate and analyze problems with mobile phone events. Test diagram of frequency guide coverage High-performance frequency scanning equipment can quickly search for scrambling code information of different frequency points, which is very useful for multi-frequency and Multi-standard network testing. Genex probe supports multi-frequency scanning. For example, 10614 and 10664 represent two frequency points, and probe can simultaneously record the scanning data of both. You can switch the display view in the same window. Multi-frequency scanning 2. 3g/2G interoperability Optimization The common planning of WCDMA and GSM networks is a common concern of 2G network operators and communication equipment vendors. You can use genex probe to test and optimize the interoperability between different systems. Genex probe is capable of switching between systems and roaming by controlling and testing mobile phones. It also measures and resolves the measurement parameters and signals of WCDMA and GSM networks in real time. 6. It is displayed in the 3g2g switching zone. When the quality of the 3G signal is reduced to below the threshold for switching from different systems, the phone cannot be switched in time, resulting in disconnection. Mobile Roaming from 3G to 2G The pause and linkage during playback can synchronize all data at a certain time, so that you can easily observe the instantaneous network parameters. 6. We can observe the process from Call Establishment (NAS Connect), RRC measurement report, to disconnection. The network does not issue a switch command throughout the process. At the activation set (mark 3), we can see that the received mobile phone's 3G signal quality in the switching area is completely unacceptable. Because the signal quality is also poor after the call, the mobile phone reselected to the GSM community and initiated a location update. Through further network data check and background data analysis, we can find out why the network does not normally switch commands and optimize them. If the reason is that the 2G cell neighbor parameter is not configured for the 3G cell, after the normal configuration, the network should be able to switch and test again. For example, after the network receives the mobile phone's different system measurement report, the network sends a switch command, and the mobile phone successfully performs the switch. When the switch is successful, the transmit power and the power of the mobile phone gradually increase and disappear obviously. It is a stable launch, and then the transmit power is instantly transferred to 2g when the switch occurs. This verifies the problem of network parameter configuration and solves the system problem. Switch from 3G to 2G 3. Concurrent service diagnosis and Optimization 3G is widely used to provide data services, just like the Internet. At the same time, the phone number is still one of its most essential services. This involves a special application form: concurrent business. Concurrent service testing capability is necessary for testing 3G network services. Genex probe provides the ability to analyze each type of data business and out-of-the-box business. Separate analysis reports can be provided. In addition, the test plan supports automatic testing of such businesses. The following settings: Concurrent business test plan establishment . In this setting, probe does not execute the test plan in sequence, but starts to execute the first test project and then automatically starts to execute the second test project. As a result, the data of mobile phones in concurrent services is collected by the system for storage and analysis. Concurrent service signaling process 5. The CM service request is a business request in the CS domain, and the service request is a business request in the PS domain. After the PS service is successfully established, you can continue to call and test the CS service to verify the CS access performance when the PS service is executed. At the same time, the data service throughput, downlink block rate, transmission power and other indicators can be further studied. The method provided by probe to automatically execute concurrent businesses provides convenient means for researching concurrent businesses and can be customized for different business types. When a business occurs, if an indicator exception is detected, such as data transmission, block rate error, or signaling exception, you can continue to optimize parameters and verification methods with the network. Concurrent service observation window 4. Intelligent Analysis Report The analysis of test data and performance indicators ultimately determines the quality of optimization. Currently, probe supports event analysis, data service, voice, VP, stream service, W, and G network events. It can be automatically output through internal automatic analysis and judgment: 1. PDP activation success rate; 2. RRC establishment success rate; 3. Speech connection time; 4. response time for data service acceptance; 5. analyze the specific cause of the disconnection; 6. Soft switching frequency; 7. Pilot pollution events Road test analysis and performance indicator Statistical Example Development Trend of road test tools We have introduced the application of some test methods for network optimization in the WCDMA system. There are many topics for network testing, covering the depth from the physical layer measurement to the application layer measurement. The content is very extensive and in-depth. The industry's road testing instruments also have their own characteristics. The road test system is integrated with comprehensive testing instruments, mobile phones, testing software, analysis software, and network regulation and network optimization experience. It is constantly updated. From a single mobile phone or scanner to the combination of the two, from the ever-increasing measurement functions to support new technologies, from data collection to automatic control, from the traditional drive test to the automatic road test system. The road test system family has different forms. The 2G and 3g pda road test tools are developed as short and refined branches. In terms of connection and ease of use, Bluetooth technology has been used in the road test system to achieve wireless connection of road test devices such as mobile phones, greatly reducing the cumbersome connection. Then, regardless of the form, it has its own characteristics, such as portable, powerful control capabilities, multi-network comparison, multi-phone support, high speed, large capacity, high coverage will meet network optimization needs from various perspectives. In addition, the extraction and analysis of road test data and the comprehensive analysis of network-side optimization data will play a final decisive role in the actual network optimization, it will also provide services to build a better network with better performance.   Http://hi.baidu.com/sdgeme/blog/item/038d71fb8569b5d6b48f31b9.html