Td-scdma System Research And Implementation Of The Mac Layer Protocol

In the third generation mobile communication standard TD-SCDMA, the MAC -layer accomplishes the mapping function between logical channel and transmission channel, and the MAC protocols,which are the main components of TD-SCDMA system users surface protocol stack, can select the appropriate transmission format for the transmission channel based on the need of logical channel resources transmit rate. This research is important to the implementation of TD-SCDMA system user plane protocol stack.This thesis widely discussed the TD-SCDMA standard which firstly described TD-SCDMA network architecture, the basic structure of the access network, Iu interfaces, Iub interface, wireless interface protocol and physical layer protocol; and then the MAC-layer protocol content, relative channel to MAC-layer, MAC-layer structures, MAC layer provides services to the upper and MAC-layer functions described in detail to study the MAC-layer for the entire TD-SCDMA system. The functions, which MAC-layer supporting, have been divided into two major parts which are scheduling and transmission of downlink data and upstream data processing. The downlink data scheduling and transmission is divided into two sub-functions that are non-HSDPA and HSDPA, while the upstream data processing is divided into two sub-functions of Capacity Allocation frames received and processing and the processing of others upstream data; On the basis of fully detailed functional requirements and the consideration of relationship among MAC-layer, RLC layer, physical layer and RRC layer, a reasonable design of the interface among them has been conducted.In the TD-SCDMA standard, Since MAC-layer protocols possess many functional entities, including MAC-b, MAC-c/sh, MAC-d, MAC-hs, MAC-e/es, MAC-ehs and MAC-i/is. This article focuses on study and design of the MAC-d entity, the data package format of MAC-d, the downlink data scheduling algorithm of MAC-d to non-HSDPA services, downlink data transmission algorithms of MAC-d to HSDPA service and processing algorithms of MAC-d to uplink data. In addition to algorithm design, the article also described the major data structures in implementation process, including the global variable in MAC-d, the data structures related to RRC configuration and data structures within the MAC-d, while the MAC-d sub-module process, RRC related configuration process, the trigger conditions for downstream data transmission and downlink scheduling of the major functions of the process to achieve have been highlighted. In the last part, the important process of the three unit tests has been introduced fully, which involves a brief introduction of the test environment, processing of MAC-d to RRC configuration message, the maintenance of MAC-d to the HSDPA service credit bucket and the transmission of MAC-d to HSDPA services downlink data.MAC-layer protocols implementation is the core of this thesis. The completed MAC protocol modules have been debugged and run through the operational test, reached a practical level, have been tried in a communications company cluster communication system.