Artiza LTE eNB Test Solutions

LTE eNB Architecture

In order to reduce Capital Expenditure (CAPEX) for LTE operators, most of equipment venders are developing LTE eNB using generic “off-the-shelf” platforms, such as ATCA, Micro-TCA, and AMC in PICMG. On the other hand, legacy proprietary platforms have been used until 3G/3.5G network era. Micro-TCA platform (see Figure 24) is one of the powerful options dedicated to applying telecom equipment especially for the use in LTE eNB. Many component venders are developing modules based on general purpose Micro-TCA modules with powerful CPU, DSP, and FPGA, with high speed memory with GbE I/F on front side. Each module in the platform can communicate with not only GbE interface as control interface from server module but also with the 10Gbps Serial Rapid I/O (sRIO) interface. Micro-TCA Connection Handler (MCH) module enables star topology on backplane, switching the packets from all of modules in the platform. 10GbE is selectable for this start topology connection on Micro-TCA.

Figure 24: MicroTCA platform

Figure 24: MicroTCA platform

The sRIO interface is used for connection between Uu side baseband module and S1/X2 side network I/F module. The baseband function and network interface function are usually implemented on different modules, and connected with sRIO I/F over MCH. Most of equipment developers use FPGAs for PHY/Baseband, DSPs or Network processors for Lower layer protocols (HARQ/MAC/RLC), and CPUs or Network processors with operation system for PDCP and upper layers, as shown in Table 2.

Table 2: LTE eNB Implementation Example
Function Implementation
PHY/ Baseband FPGAs/ASSPs
Low layer protocol DSPs/Network processor
PDCP and upper layer protocol CPUs/Network processor with operation system

eNB venders can minimize their development effort using generic components, not only with hardware module but with intellectual property like baseband logical circuit on FPGAs, protocol stack software. An example of LTE eNB implementation on Micro-TCA platform is shown in Figure 20, Figure 21 and Figure 22.

Figure 25: LTE eNB implementation example (C-plane)

Figure 25: LTE eNB implementation example (C-plane)

Figure 26: LTE eNB implementation example (U-plane)

Figure 26: LTE eNB implementation example (U-plane)

Figure 27: LTE eNB implementation on MicroTCA platform

Figure 27: LTE eNB implementation on MicroTCA platform

Figure 22 shows an example of eNB implementation, which connects two eNB that covers six sectors over two cells. The eNB is connected to S1/X2 with two GbE interfaces.