Contention Random Access Procedure Implementation For The LTE-TDD

With the continuous development and application of the wireless broadband technology, the technology of the LTE(Long Term Evolution) is constantly maturing, and it has entered the final stages of the commercialization which come true the accessing and debugging for LTE communication system. Many basic features of the LTE protocol have been tended to unify, and random access function is to achieve vital features of the broadband accessing terminal. It is the basic and important performance indicator for LTE 4G communication system to come true. The LTE random access function of the specific implementation is different from the communication device manufacturing factories. It is the great difference which random access procedure comes true between the PHY layer and the MAC layer. You need to put forward a more reasonable, relatively and strong interoperability implementation solution and we need to verify the random access capability by rationality and correctness testing mode.The goal of the LTE is achieving the high rate network speed of the uplink and downlink under the different bandwidth conditions, such as 1.4MHz, 3MHz, 5MHz, 10 MHz, 15 MHz and 20 MHz. It is very important measuring standard for LTE technology to obtain the stable, accurate wireless signal for accessing to the LTE communication system. When LTE communication system is achieved, we adopt the fashion which the LTE protocol stack is working on the Linux operating system platform, and we also research and test on the Linux platform.The LTE communication system could be divided into two parts according to the work mechanism, LTE-TDD and LTE-FDD. The LTE-TDD is stressed in the study, and how to transform into the random access function of the LTE communication system from the random access protocol of the 3GPP protocol, and then we carry through the effective and scientific testing. Meanwhile we will introduce the random access ways to come true and radio protocol. Finally we improve and develop the solution for the random access procedure.We have carried out as following steps for coming true the random access function of the LTE communication system:1. We understand and analyze for the access random function in the 3GPP protocol. It is understood and analyses for the random function of the 3GPP protocol in the study. We have designed the suit of the scientific random access solution according to the random access of the characteristic and peculiarity of the LTE communication system.2. According to the 3GPP protocol, the contention random access procedure is designed in the LTE-TDD communication system. The design of the contention random access procedure could be divided into two parts. One part is the design of the physical random access procedure to true come for the contention random access procedure. The other part is the design of the contention random access procedure which comes true in the MAC layer. During the processing of the design of the MAC for the contention random access procedure, the main working was to design the function modules in the MAC. And the function and role of the modules which is in the LTE-TDD communication system are introduced.3. The contention random access procedure of the 3GPP protocol is achieved in the real LTE-TDD communication system. According to the message of the 3GPP protocol interacting for the contention random access procedure and it is come true the contention random access procedure function in the real LTE-TDD system,and then every function module which make the role and work Principle in the LTE-TDD communication system for the contention random access procedure carried out achieving and expressing. And the messages for achieving the contention random access procedure are particularly defined and come true.4. The contention random access procedure implementation for the LTE-TDD is scientificly tested. And some parameters are tested according to in the 3GPP protocol defined. Finally contention random access function implementation for the LTE-TDD is successfully verified.5. Through the contention random access procedure achieved, access success rate of the UE have been made great progress, and the stability and reliability of the wireless link have also been improved between the LTE-TDD communication station and the UE.