Wuhan Tabebuia Technology Co., Ltd.

Overview Using open-source system platforms and hardware to study small-scale base stations is an important direction of research in the fields of radio and LTE wireless communications. Traditional commercial base station equipment is expensive, has long development cycles, high operational complexity, and cumbersome functionality changes. To address the issue of complex functionality changes and long development cycles in the study of LTE wireless communication base stations, the proposed solution adopts the open-source OAI 5G and srsRAN software systems and a software-defined radio (SDR) hardware platform to build real-time operating base stations for research on interactions with terminals. This approach avoids the issues of bulky and expensive base stations with long development cycles, improving the efficiency of research on base stations and terminal interactions. Solution Based on the USRP-LW/SDR-LW series of software-defined radio hardware, combined with software platforms such as srsRAN and OpenAirInterface (OAI) 5G, a 4G/5G simulation base station and terminal can be built. By using different models of software-defined radio hardware and various base station configuration parameters, different functionalities can be achieved. This system can fully simulate the end-to-end protocol stack, accurately model the base station, terminal, and core network, while complying with the corresponding 3GPP protocol specifications. It supports integration with commercial equipment (such as commercial terminals and core networks) and allows secondary development based on the protocol stack. Figure 1 shows the LTE system architecture, consisting of three parts: the core network (EPC), the base station (eNB), and the user (UE). Each part implements its corresponding functions according to the 3GPP LTE protocol stack. On the UE side, the architecture includes functions such as PHY, MAC, RLC, PDCP, and RRC. The UE communicates with the eNB for uplink and downlink data exchange via the air interface. In the middle is the eNB architecture, which includes the air interface with the UE and the S1-U and S1-MME interfaces with the core network. On the right side is the EPC, which consists mainly of network elements such as the MME, S-GW, and P-GW. Figure 2 shows the NR system architecture. The 5G radio interface inherits the 4G protocol stack, with an additional SDAP layer introduced in the user plane to mark Quality of Service (QoS). The 5G system architecture is also divided into three parts: the user (UE), the 5G base station (gNodeB), and the core network (5GC). The ng-eNB, gNodeB, and 5GC are connected through the NG interface.

Overview Large-scale Multiple-Input Multiple-Output (MIMO) technology is a key technology in 5G network communications. It utilizes large-scale antenna arrays to achieve efficient signal transmission and reception. By increasing the number of antennas, large-scale MIMO technology can significantly enhance the channel capacity and spectral efficiency of the system without requiring additional spectrum resources or transmit power. To realize the 5G vision and meet the critical performance requirements for spectral efficiency, it is essential to prototype and validate large-scale MIMO and other related technologies. Since computer-based simulations alone cannot address many of the complex unresolved issues, it is necessary to develop prototype systems that can operate in real-time under actual channel conditions and transmit/receive real RF signals. A hardware-in-the-loop (HIL) system, which combines simulation software on a computer with a software-defined radio (SDR) platform, can address these challenges, facilitating the transition from theoretical simulation to practical application and thereby accelerating the development of next-generation communication systems. Solution This solution is implemented using Luowave USRP-LW N321 platform, which primarily consists of the programmable RF front-end USRP-LW N321, servers, switches, and the clock source OctoClock-LW-G. Setup Diagram Recommended Model The USRP-LW N321 is a network software-defined radio that can provide reliability and fault-tolerant capabilities for deployment in large-scale and distributed wireless systems. It is a high-performance SDR that uses a unique RF design to offer 2 RX and 2 TX channels in a half-width RU size. The flexible synchronization architecture supports a 10 MHz clock reference, PPS time reference for external TX LO and RX LO inputs, enabling a phase-coherent MIMO test platform. OctoClock-LW-G is a device allocation system for high-precision clock sources. It is very useful for users who wish to establish a multi-channel system and synchronize to a common reference time. For instance, we can use OctoClock-G to perform coherent operations on USRP N210 and synchronize with the system. This enables many phased array applications, such as beamforming, super-resolution direction finding, diversity combination, or the design of MIMO transceivers.

5G Millimeter Wave USRP Solution Overview As the demand for ultra-high data transmission, low latency and large capacity in the mobile communication market is growing increasingly strong, the communication industry needs to develop other frequency bands of 5G wireless technology to alleviate the current pressure on wireless spectrum usage in networks.   The so-called 5G millimeter wave, according to the 3GPP 38.101 protocol, 5G NR mainly uses two frequency bands: FR1 frequency band and FR2 frequency band. The frequency range of FR1 frequency band is 450MHz - 6GHz, also known as the Sub-6GHz frequency band; the frequency range of FR2 frequency band is 24.25GHz - 52.6GHz, usually referred to as millimeter wave.     Advantages of 5G mmWave High speed and large capacity: mmWave can provide extremely high data transmission speed, with peak rate reaching 30 Gbps, supporting simultaneous connection of a large number of devices, and suitable for scenarios such as live streaming of high-definition video and virtual reality. Low latency: mmWave technology can achieve faster response by reducing communication latency. It is very friendly for scenarios that require real-time data transmission, such as autonomous driving and remote control. High directivity: mmWave has good directivity and narrow beams, which is conducive to precise positioning and transmission, and can improve signal security and reduce interference. All-weather characteristics: mmWave propagation is much less affected by climate, and has all-weather characteristics. Currently, USRP transceivers can send and receive RF signals below 6 GHz, covering the Sub6G frequency band. To meet the requirements of NR FR2, LUOWAVE has deeply customized mmWave expansion modules for USRP, which can upconvert intermediate frequency signals to mmWave frequency band, thereby helping users quickly establish 5G mmWave mobile communication systems.   Solution The 5G millimeter-wave communication system is built based on the USRP-LW/SDR-LW series of software-defined radio platforms, millimeter-wave expansion modules and its OpenAirInterface (OAI) 5G software platform. It has the function of simulating the 5G NSA/SA network environment and can support the exploration of related technologies for 5G millimeter-wave communication. Through using different types of software-defined radio hardware and different base station configuration parameters, different functions can be achieved. This system can fully simulate the end-to-end protocol stack, fully simulate base stations, terminals and core networks, and meet the corresponding 3GPP protocol specifications. It supports interfacing with commercial equipment and supports secondary development based on the protocol stack.   Setup Diagram Base station side: It is composed of one high-performance radio independent device SDR-LW 2974, one millimeter-wave expansion module up-conversion module and one down-conversion module, and two millimeter-wave horn antennas.     Terminal side: It is composed of a software-defined radio device USRP-LW B210, a millimeter-wave extension module up-conversion module, a down-conversion module, an upper computer, and two millimeter-wave horn antennas.         Related Products The processing requirements of 5G-NR are much higher than those of 4G, thus requiring high-performance SDR devices or even more advanced PCs as the host computer for USRP. Through the accompanying millimeter-wave expansion module and up-converter, continuous frequency conversion from 24GHz to 44GHz can be supported, meeting the research needs of 5G millimeter-wave communication. (1) SDR-LW SeriesThe SDR-LW series is a high-performance SDR standalone device launched by Luoguang Electronics. It consists of an onboard processor, FPGA, and RF front-end. By working in synergy with the Intel X86 processor and FPGA, the flexibility of software-defined radio equipment is enhanced. The host of the SDR-LW series device can run 5G base station/terminal software, and the front-end realizes signal transmission for base stations and terminal devices through horn antennas. The integrated design framework enables it to quickly build prototypes of high-performance mobile wireless communication systems. It is recommended to choose the SDR-LW 2974 and SDR-LW 3980 models: (2) USRP-LW SeriesUSRP-LW N321 is a high-performance software-defined radio device featuring an instantaneous bandwidth of up to 200 MHz RF front-end, supporting MIMO configuration, and equipped with high-speed ADC and DAC. It can handle complex signal processing tasks and meet diverse wireless communication requirements. Soft base stations and soft terminals are set up on the PC connected to USRP-LW N321 to implement NR wireless protocol stack functions. USRP-LW N321 completes digital-to-analog conversion and completes the transmit and receive functions at the RF end. The baseband processor of USRP-LW N321 adopts Xilinx Zynq-7100 SoC, integrating a large-scale user-programmable FPGA and dual-core ARM CPU, providing strong support for real-time and low-latency processing. By using SFP+ and QSFP+ ports, USRP-LW N321 can transmit high-throughput I/Q data streams to the host PC or FPGA coprocessor, meeting the requirements of high-speed data processing. It supports remote execution tasks, such as software update, restart, and factory reset, thereby simplifying the control and management of the radio network.