Research And System Design On MAC Sublayer Of LTE Terminal

LTE is not the specification standard of the4th generation mobile communicationas people generally considered, but the technology standard upgrade of GSM/UMTS，and it s the mainstream technology in the evolution from3G to4G. LTE has refinedand enhanced the air access technology of3G, OFDM and MIMO are thecore technologies.The LTE protocol system is aimed at the Uu air interface (theinterface between UE and eNodeB), and MAC sublayer plays an important role in thesystem, it defines how to transmit the data on the medium. MAC sublayer has toaccomplish the functions include the mapping between logical channel and transmissionchannel，the multiplexing and demultiplexing of data, resource scheduling and hybirdautomatic repeat request control, etc. The E-UTRA defines two kinds of MAC entity,one was located in UE, another was located in E-UTRAN. MAC sublayer forms aconnecting link in LTE protocol system, and the vital parameters that measure wirelessnetwork quality like wireless frequency resource utilization, bits error ratio and delay,are affected directly by the design and realization of MAC sublayer.Based on the study of LTE protocol system, the MAC sublayer of LTE terminal isdesigned and realized in this dissertation. The dissertation begins with an introduction tothe development and evolution of wireless communication system, then LTE networkarchitecture and protocol system are described. Secondly, based on the study of MACsublayer protocol, functional requirements and main processes are analyzed, theninterfaces between RLC sublayer and MAC sublayer, interfaces between PHY layer andMAC sublayer are designed, the overall structure of MAC sublayer in LTE terninal isdetermined. After the function partition of MAC sublayer, the process analysis andwork flow desigment of main functions, such as data transmitting of uplink, datareceiving of downlink, HARQ and auxiliary functions like buffer status report andschduling request are provided. Finally, on account of the study and design above,MAC sublayer of LTE terminal is partly implemented using theprogramming language C++under the environment of Windows XP, correctnessand easibility of the software system was verified through the transmission andplaying of video file. According to the research in this dissertation and the technicalrequirements of next generation broadcasting-wireless, the design and implementation can be the foundation and reference for developing the bi-directional datacommunication part in next generation broadcasting network.