Td-scdma Simulate Bbu Software Design And Implementation

There are advantages of the solution of BBU (Base Band Unit) combined with RRU (Remote RF Unit) in TD-SCDMA networks indoor coverage. The solution can save site resources, reduce the number of indoor and outdoor feeder, has flexible networking and easy expansion abilities, compared with traditional solutions. It is the mainstream of the future network development. China Mobile has accelerated the construction of TD-SCDMA network, plans to cover 100% of cities of mainland China in 2011. In the process requires a lot of RRU.Testing is an important part of RRU research and development. It is low efficiency and high cost to use common BBU in RRU testing. The manufacturers without BBU product are lack of means to test RRU. BBU simulator is a kind of product aiming at RRU testing, has the similar features to the BBU, and more rich functionality in testing. It is simple design and can complete the work of RRU test more efficient and cheaper. So it has important practical value.This article carries out the software design of BBU simulator. Starting from the RRU test by analyzing the test methods, conditions, then summed up the hardware and software features. Describes the hardware platform design, describe the chips and on-board interfaces of the main board. Design the whole software architecture based on the chips features and software features. The top layer is divided into three subsystems. Define the functionality and performance requirement of each subsystem, and the interface between subsystems. Carry out the detail design of each subsystem. Divide them into smaller software modules, and define the interfaces between sub-modules, processing and running threads.Run the software on main board. Set up a typical RRU test environment to do BBU simulator functionality and performance testing. Design three test cases to verify Ir protocol processing, downlink signal transmission and uplink demodulation functions and performance. In the downlink test, RRU transmit 9 carriers, 5dBm per carrier, and every carrier's time slot has sixteen QPSK modulation DPCHs. The EVM is 4.51% rms, and power deviation is±0.5dBm. In uplink demodulation test, receiving -113dBm 12.2kbps service signal, the BER is 0.08% and meet the voice service. Show the software of BBU simulator meet the demand of TD-SCDMA RRU test.Now the BBU simulator designed in this article has been applied in some RRU manufacturers, has achieved good economic value.