New problems of focusing TD-LTE test in same-frequency networking

Latest Advances in TD-LTE Testing

At present, the first phase of core network, transmission, bearing and security testing work has been completed in the six test fields of TD-LTE. The results meet the test expectations, and all of them have entered the formal test conditions, in the future, the wireless performance, multi-antenna, terminal, indoor distribution system, network management and other aspects of the TD-LTE system will be carried out gradually testing.

Aside from the past industrial trend and Technical Characteristics publicity, we can see that this seminar highlights the obvious "pragmatic" characteristics. both operators and manufacturers have put forward a series of practical ideas.NetworkingAnd quickly aroused the attention of the industrial chain.

Same-frequency networking performance becomes the focus of scale tests

In the TD-LTE network, the same frequency network is the same base station in different communities using different frequency points, the same frequency network mode is the same as the base station all cells using the same frequency points, in contrast, due to the advantages of high frequency utilization, flexible deployment, low band requirements for terminal support, reduced complexity of RF channel, and reduced terminal price, the same-frequency networking has been widely used in TD-LTE outdoor network layout. However, in the actual implementation, due to problems related to synchronous channel, user capacity, Smart Antenna use, and so on, coupled with TD-LTE wireless testing content and networking capabilities have not been completed, therefore, the same-frequency networking performance has become a key concern of operators in current tests.

When talking about this problem, Zhang Tong said that the same-frequency networking performance will also be the main test content of the subsequent scale test network, china Mobile will focus on observing whether the edge user throughput meets business needs under high load conditions. He also suggested that the industry should also strengthen research on interference coordination and Interference Suppression algorithms to improve the performance indicators of the same-frequency network.

Capacity and efficiency to be verified

Shen Jia, Chief Engineer of the wireless and mobile Research Department of the Institute of Standards at the Institute of Telecommunications and research, has received much attention for the same-frequency networking:

First, the question of "ability and inability" is that the core broadcast channels, synchronous channels, and other channels supporting the basic operation of mobile networks are still unclear if they can be connected to the same-frequency networks;

Second, the problem of "many and not many", that is, whether the TD-LTE network can carry a large number of online users forever, still can effectively networking;

Third, the question of "high and low" is whether it can achieve high spectrum efficiency in the same-frequency networking environment, forming a competitive advantage with lte fdd and WiMAX systems.

Shen Jia said, Because TD-LTE and lte fdd adopt the same technology anti-interference design, the same frequency Networking capability is no longer a problem, however, whether large-capacity users and high-efficiency networking are supported remains to be verified and improved by the vendors.

Ericsson LTE product experts on the TD-LTE co-frequency network coverage issues expressed great concern. According to him, at the beginning of the design, LTE was designed to use the same-frequency networking to improve the spectrum utilization efficiency. In the design of public control channels for LTE downlink, transmitting diversity and other technologies can be used to enhance the performance of control channels. In addition, there is no difference between lte fdd and TD-LTE in the control channel, so the same frequency network of TD-LTE can learn from the commercial deployment experience of lte fdd.

Shen Jia also mentioned another problem that needs to be solved in the same-frequency networking, that is, the impact of smart antennas. In theory, smart antennas can reduce the interference probability of adjacent cells. However, in actual network deployment, smart antennas reduce the interference frequency in some directions, however, it may also cause greater interference in some ways and cause greater volatility, which will directly affect the application of the terminal. Shen Jia said frankly, the same frequency of TD-LTE networking capabilities also need to test the specific test.

Using C-RAN to promote the integration of the whole network

For TD-LTE networking, Yao lei, deputy general manager of TDD products of ZTE, proposed the feasibility of GSM/C-RAN/TD-SCDMA multi-network integration through TD-LTE multi-cell merging technology.

The two-layer structure of the existing LTE flat network is composed of EPC and eNodeB. Although the efficiency is higher, the use of this structure reduces the control capability of the base station. Yao Lei said, the prototype of C-RAN is multi-cell merger, so that the terminal to see different cell signal is multi-path signal rather than multi-cell different signal, thus greatly reduce interference. This multi-cell merge technology, ZTE in CSL network has done the current network verification, can bring benefits to the TD-LTE network.

After clarifying the structure of the C-RAN target network, China Mobile is also very concerned about how to complete GSM/C-RAN/TD-SCDMA through TD-LTE. In this regard, ZTE has launched a large capacity baseband pool solution, which uses existing products based on its unique FS switching board, A single rack can achieve 648 carrier frequency sharing, and three racks can achieve 1944 carrier fan sharing. On the other hand, the "color light Direct Drive" transmission technology can improve the transmission efficiency, reduces the requirements for transmission over the current network.

Speaking of triple play, Yao Lei gave the emergence of A network F/A dual-mode RRU data, that is, the existing TD-SCDMA network has A total of 0.22 million base stations, the total number of outdoor base stations is 0.14 million, of which, f/A dual-band RRU accounts for 80 thousand. That is, if the development of TD-LTE in F frequency band, can make full use of the existing TD-SCDMA resources, so as to complete the continuation of TDD industry dominated by domestic manufacturers.

The Analysis of TD-LTE same frequency networking technology this article will introduce to you here, this is a new networking technology, he marked the network development has risen to a new step.