Analysis of family base station technology in LTE System (1)

Modern mobile communication tends to provide high-speed transmission multimedia services. The birth of LTE family base stations effectively improves the coverage, throughput, and transmission experience of the system in hot areas.

In the standardization process of LTE, the concept and technology of a family base station HomeeNodeB and HeNB came into being. Unlike traditional cell communication base stations, a family base station is a small, indoor, and flexible base station. Statistics show that for high-speed multimedia services, more application scenarios of broadband services are indoor and hotspot areas. However, traditional cellular mobile communication methods do not support such requirements. The birth of family-class base stations aims to solve such conflicts and provide indoor users who need multimedia services with a better user experience.

For the family-class base station technology of the LTE system, in terms of business, the LTE system requires a downstream transmission rate of 100 Mbit/s and an upstream transmission rate of 50 Mbit/s, in addition, different transmission policies can be formulated based on different QoS requirements of different services. LTE also has higher and higher transmission latency requirements. The maximum latency of the user layer must not exceed 5 ms to meet the requirements of the access network, the maximum latency of the control layer cannot exceed 100 ms.

From a technical point of view, the downlink transmission of the LTE system adopts the OFDMA access mode. The uplink transmission uses the single-carrier FDMA, which effectively suppresses interference between users in the community and efficiently utilizes the broadband spectrum, in addition, the average peak ratio of transmission signals is reduced. The introduction of MIMO technology greatly increases the data transmission rate of LTE. In addition, AMC, power control, interference coordination and other technologies play a significant role in improving the performance of the LTE system.

Overall Structure

In addition to the access network, the LTE system has changed the wireless access mode, introduced some enhancement technologies, and greatly changed the overall network structure. The LTE system adopts a flat network structure, removes the RNC of the WCDMA system, and upgrades NodeB to eNodeBenhancedNode B ), eNode B integrates previous RNC functions, such as wireless network resource management, switching management, and traffic collection, further reducing transmission processing latency and enhancing the flexibility of network operation. In the LTE system, base station eNB is a comprehensive and powerful access network node.

The LTE system of family-class base stations is introduced. The overall network structure is basically the same as that of the LTE system without family-class base stations. However, family-class base stations must be small in size and have high installation flexibility, the communication between the corresponding family base stations is relatively complex. Currently, the LTE specification does not support X2 interfaces between family base stations. Figure 1 shows the structure of the LTE system that introduces the family base station.

The E-UTRAN introduces HomeeNBGateway, HeNB GW) in the logical structure, which is equivalent to extending the S1 interface between the family base station and the core network, so that more family base stations can be configured in the system. We can think that the family base station gateway is used to centralize the control layer C-Plane), especially a concentrator of the S1-MME interface gateway module. The S1-U interface at the home base station end can be terminated at the home base station gateway or through the direct user layer (U-Plane) between the family base station and the service gateway for logical connection.

From the perspective of mobile management module equalitymanagemententity), there is no difference between a family base station and an ordinary LTE base station. For family base stations, family base station gateways are equivalent to mobile management modules. Of course, the definitions and functions of the S1 interface of the family base station and the gateway connected to the EPC through the family base station are the same. When the family base station gateway is connected to the EPC, users of the family base station gateway service can switch between MME modules when moving between cells. Family base stations support all functions of ordinary LTE base stations. The connection process between the family base stations and EPC is also the same as that between ordinary LTE base stations.