Research And Development Of A Multi-core CPU Based Software Radio Platform And Applications

With the rapid development of mobile communications, the traditional communication devices, based on dedicated hardware design, are not compatible with each other among various communication standards and systems. While software radio can integrate different wireless systems on a single hardware platform, and can implemen-t different wireless protocols using software. Many current software radio platforms are based on either programmable hardware such as field programmable gate arrays (FPGAs) or embedded digital signal processors (DSPs). Such hardware platforms can meet the pro-cessing and timing requirements of modern high-speed wireless protocols, but program-ming FPGAs and specialized DSPs are difficult tasks.In contrast, software radio platforms based on general-purpose processor (GPP) architectures, such as commodity PCs, have the opposite set of tradeoffs. Developers program to a familiar architecture and environ-ment using sophisticated tools, and radio front-end boards for interfacing with a PC are relatively inexpensive.However, since PC hardware and software have not been designed for wireless signal processing, existing GPP based software radio platforms can achieve only limited performance.This thesis presents the design and implementation of a multi-core CPU based soft-ware radio platform-SORA. Then, designs an efficient and modular software program-ming model-CORA for wireless digital signal processing. Further, implements an IEEE802.11n2×2MIMO system based on CORA programming model on SORA software radio platform. Finally, discusses the inefficiency of MAC protocol in WLAN and pro-poses a cross-layer solution-FICA. In summary, the contributions of this thesis are as follows:1. Design and implement a multi-core CPU based software radio platform-SORA.This thesis presents SORA, a fully programmable software radio platform on com-modity PC architectures. SORA combines the performance and fidelity of hard-ware software radio platforms with the programmability and flexibility of general-purpose processor software radio platforms. SORA uses both hardware and soft-ware techniques to address the challenges of using PC architectures for high speed software radio platform. The SORA hardware components consist of a radio front-end for reception and transmission, and a radio control board for high-throughput, low-latency data transfer between radio and host memories. SORA makes exten-sive use of features of contemporary processor architectures to accelerate wireless protocol processing and satisfy protocol timing requirements, including using ded-icated CPU cores, large low-latency caches to store lookup tables, and SIMD pro-cessor extensions for highly efficient physical layer processing on GPPs. A demon-stration radio system called SoftWiFi has been implemented on the SORA platfor-m. SoftWiFi seamlessly communicates with commercial802.11a/b/g devices, and achieves equivalent performance as commercial devices at each modulation rate.2. Design and implement a flexible, modular digital signal processing programming model-CORA.Software radio increasingly becomes a powerful tool for academic wireless research as well as industry prototyping due to its flexibility and programmability. Imple-menting wireless protocols on software radio in practice, however, remains a chal-lenging task. It is mainly due to the lack of an efficient modular software architec-ture for high-performance digital signal processing. The thesis presents a flexible and modular software programming model-CORA to facilitate signal processing implementation by taking advantages of multi-core parallel processing features and the optimization capabilities of modern compilers, CORA is a flexible, efficient, low-latency and high code reusable programming model. Programmers can rapidly develop different high execution efficiency communication protocols and physical layers with CORA’s auxiliary library.3. Implement a802.1In2x2MIMO system on SORA.Taking802.11n2×2MIMO for instance, the thesis introduces some physical lay-er encoding/decoding processes and corresponding algorithms, and discusses the practical issues while implementing such a communication system and gives out feasible solutions. Implements the physical layer encoding/decoding process base on CORA programming model and makes optimization on these algorithms target-ing for multi-core CPU architecture to improve processing speed. Implements the prototype communication system on SORA platform and verifies the encoding/de-coding throughput could meet the real-time computation requirements. Evaluates the physical layer decoding performance in real channel. Results show that the soft-ware implemented MIMO system achieves similar performance with commercial802.11n devices. The development and experiments also further validate the ease of use and effectiveness of CORA programming model. 4. Fine-grained channel access in WLAN-FICA.The high flexibility of SORA promotes the development of new wireless systems. This thesis discusses the problem that the overhead of MAC protocol progressive-ly degrades data throughput efficiency with the increasing physical layer data rate in WLAN. To solve this problem, the thesis introduces a cross layer design of fine grained channel access MAC protocol-FICA. The entire channel is divid-ed into several sub-channels with equal width. Multiple terminals accesses these sub-channels according to their traffic requirements at the same time, thereby im-proving the overall efficiency. Based on SORA software radio platform, FICA ver-ifies the rationality and feasibility of the design through experiments. System level simulations based on NS-3demonstrates that FICA can significantly improve the efficiency of WLAN compared to traditional MAC protocol (from10%～600%).