前言对于5G系列在下主要在业余时间进行学习和总结分享出来以供参考。为了便于理解5G协议开始加入openairinterfaceOAI开源项目介绍5G协议分析和5G代码分析不定期交替更新。OAI安装搭建已经在OAI 5G NRUSRP B210安装搭建一文中做过介绍今天先大体看一下OAI的目录结构和主函数结构。目录结构openairinterface5g├── ci-scripts : Meta-scripts used by the OSA CI process. Contains also configuration files used day-to-day by CI. 已忽略├── cmake_targets : Build utilities to compile (simulation, emulation and real-time platforms), and generated build files. 存放编译脚本以及编译生成的可执行程序程序编译在这里面├── common : Some common OAI utilities, other tools can be found at openair2/UTILS. OAI公共代码├── doc : Contains an up-to-date feature set list and starting tutorials. 最新的功能集列表和入门教程├── executables : Top-level executable source files. 已忽略├── LICENSE : License file.├── maketags : Script to generate emacs tags. 已忽略├── nfapi : Contains the NFAPI code. A local Readme file provides more details. NFAPI接口代码├── openair1 : 3GPP LTE Rel-10/12 PHY layer / 3GPP NR Rel-15 layer. A local Readme file provides more details. 物理层代码│ ├── PHY 物理层│ ├── SCHED LTE基站侧调度│ ├── SCHED_NBIOT NBIOT调度│ ├── SCHED_NR NR基站侧调度│ ├── SCHED_NR_UE NR UE侧调度│ ├── SCHED_UE LTE UE侧调度│ └── SIMULATION : PHY RF simulation. 物理层RF仿真├── openair2 : 3GPP LTE Rel-10 RLC/MAC/PDCP/RRC/X2AP LTE Rel-14 M2AP implementation. Also 3GPP NR Rel-15 RLC/MAC/PDCP/RRC/X2AP. MAC, RLC, PDCP, RRC, NGAP全部在openair2目录下│ ├── COMMON│ ├── DOCS│ ├── ENB_APP│ ├── F1AP│ ├── GNB_APP│ ├── LAYER2/RLC/ : with the following subdirectories: UM_v9.3.0, TM_v9.3.0, and AM_v9.3.0.│ ├── LAYER2/PDCP/PDCP_v10.1.0│ ├── M2AP│ ├── MCE_APP│ ├── NETWORK_DRIVER│ ├── NR_PHY_INTERFACE│ ├── NR_UE_PHY_INTERFACE│ ├── PHY_INTERFACE│ ├── RRC│ ├── UTIL│ └── X2AP├── openair3 : 3GPP LTE Rel10 for S1AP, NAS GTPV1-U for both ENB and UE. S1AP,NASSCTP,GTP-U在openair3下│ ├── COMMON│ ├── DOCS│ ├── GTPV1-U│ ├── M3AP│ ├── MME_APP│ ├── NAS│ ├── S1AP│ ├── SCTP│ ├── SECU│ ├── TEST│ ├── UDP│ └── UTILS└── targets : Top-level wrappers for unitary simulation for PHY channels, system-level emulation (eNB-UE with and without S1), and realtime eNB and UE and RRH GW.主函数结构主函数main位于executables/nr-softmodem.cMain├── load_configmodule(argc,argv,CONFIG_ENABLECMDLINEONLY) :读取nr-softmodem附带的启动参数。├── logInit() : log初始化。├── configure_linux() :锁定CPU状态避免CPU因电源管理进入节能模式设置CPU运行在超频状态。├── itti_init(TASK_MAX, tasks_info) :为每个模块task创建数据队列。├──init_opt()设置pcapwireshark或tshark抓包。├──netlink_init() :初始化网络套接字addr收发端口参数最后会用于PDCP recvmsg。├──pdcp_netlink_init()│ └── threadCreate(pdcp_netlink_thread, pdcp_netlink_thread_fct, (void*)NULL, PDCP netlink, -1, OAI_PRIORITY_RT_LOW )创建pdcp线程│ ├──recvmsg(nas_sock_fd, nas_msg_rx, 0)数据接收函数│ └── lfds611_queue_guaranteed_enqueue(pdcp_netlink_queue_enb[module_id], new_data_p)将数据插入队列├──create_gNB_tasks(1)创建gNB的一些线程│ ├──itti_create_task(TASK_SCTP, sctp_eNB_task, NULL)│ ├──sctp_eNB_init();│ ├──sctp_eNB_process_itti_msg(NULL)创建socketbindlisten│ ├──itti_receive_msg(TASK_SCTP, received_msg);│ ├──sctp_create_new_listener();│ └──sctp_send_data();│ ├──itti_create_task(TASK_X2AP, x2ap_task, NULL│ ├──itti_create_task (TASK_NGAP, ngap_gNB_task, NULL) 创建NGAP线程│ ├──ngap_gNB_init(); NGAP初始化│ ├──ngap_gNB_process_itti_msg(NULL)NGAP编解码UE上下文维护│ ├── rrc_gNB_process_NGAP_DOWNLINK_NAS(msg_p, msg_name_p, instance, rrc_gNB_mui);│ ├──rrc_gNB_process_NGAP_PDUSESSION_SETUP_REQ(msg_p, msg_name_p, instance);│ └──rrc_gNB_process_NGAP_PDUSESSION_RELEASE_COMMAND(msg_p, msg_name_p, instance);│ ├──itti_create_task (TASK_UDP, udp_eNB_task, NULL)│ ├──itti_create_task (TASK_GNB_APP, gNB_app_task, NULL│ ├──configure_nr_rrc(gnb_id)rrc配置│ ├──init_pdcp()pdcp初始化│ ├──itti_create_task(TASK_CU_F1, F1AP_CU_task, NULL)│ └──itti_receive_msg (TASK_GNB_APP, msg_p)从TASK_GNB_APP队列里面取数据进行处理│ ├──itti_create_task (TASK_RRC_GNB, rrc_gnb_task, NULL)创建RRC实体│ ├──itti_receive_msg(TASK_RRC_GNB, msg_p)从TASK_RRC_APP队列里面取数据进行处理│ ├──init_NR_SI(gNB_RRC_INST *rrc, gNB_RrcConfigurationReq *configuration)MIB和SIB1编码│ ├──nr_rrc_gNB_decode_ccch(......)CCCH解码│ └──rrc_gNB_decode_dcch(......)DCCH解码├── init_gNB(single_thread_flag,wait_for_sync)为gNB实体分配资源以及初始化├──init_NR_RU(get_softmodem_params()-rf_config_file)初始化RRU内部将创建RRU相关线程├──init_eNB_afterRU();│ ├──phy_init_nr_gNB(gNB,0,0);phy初始化│ └──init_gNB_Tpool(inst);└──itti_wait_tasks_end()while死循环。