Software Defined Radio Techniques Research Articles

A Narrow-Band Indoor Positioning System by Fusing Time and Received Signal Strength via Ensemble Learning

The Internet of Things (IoT) is an emerging paradigm to integrate the physical world into cyber systems by connecting various devices, which sense and control the surrounding objects. For the upcoming IoT era, narrow-band signals will play an important role in the exchange of sensor data and control signals in IoT networks. Indoor positioning is critical for many IoT applications, such as asset tracking, smart buildings, smart e-health, and smart cities, but it is very challenging to achieve accurate indoor positioning with narrow-band signals because of multipath propagation. In this paper, we design a positioning system using narrow-band signals, particularly ZigBee signals, based on an enhanced fingerprinting algorithm by fusing received signal strength (RSS) and time information. We first investigate the feasibility of time-based fingerprinting by handling the challenges as synchronization compensation among anchor nodes and design of sub-sample timestamps with a resolution of nanoseconds. Second, we design a feature-based fusion approach to fuse and standardize time and RSS fingerprints. Third, we adopt a random forest regression model to design an enhanced pattern matching algorithm for fingerprinting. We implement the proposed algorithms with software-defined radio techniques. In the given experiment results, we find that the positioning system achieves a mean positioning accuracy of 1.61 m, which represents a 36.1% improvement over traditional RSS-based fingerprinting.

A Practical FPGA-Based Architecture for Arbitrary-Ratio Sample Rate Conversion

Many digital systems for telecommunications are implemented via the Software Defined Radio technique today. In such systems, digitally implemented modules to interface analog-to-digital converters with the rest of the system working at a different clock rate can be required. When implementing these modules, generated spurious harmonics and limited hardware resource problems can be critical factors in embedded applications. The article describes a Field-Programmable Gate Array (FPGA) circuit for arbitrary-ratio re-sampling of signals in the Low Frequency to Very High Frequency bands, intended for Software Defined Radio applications. The proposed resampler allows to control Spurious Free Dynamic Range while providing a simple, practical interface between the input and output clock domains that requires no additional clock, thus making it appropriate for FPGA clock-limited designs. Both up-sampling and down-sampling variants are presented. Resource utilization for FPGA implementations is also discussed.

Test of DMB-T Signal Based on Software Defined Radio Technique

With the release of the standard, digital television terrestrial broadcasting is being gradually extended in many places. In order to speed up the extension and the application, also to evaluate the existing digital television terrestrial broadcasting system, we need a easy-to-use signal analysis and measurement system. The traditional signal measurement method is through the special hardware circuit to realize, but that method is high cost, and the system structure is complex and single function. To improve the flexibility of the system , we realize the system based on virtual instrument technology. In hardware section, this thesis described the block diagram of the system and the introduction of the NI vector signal analyzer. In software part, this thesis described the overall test system based on LabVIEW and the realization of the system features multi-threading, each step of synchronization signals achieved. DOI: http://dx.doi.org/10.11591/telkomnika.v11i3.2308 Full Text: PDF

Study on Test of DMB-T Signal Based on Software Defined Radio Technique

With the release of the standard, digital television terrestrial broadcasting is being gradually extended in many places. In order to speed up the extension and the application, also to evaluate the existing digital television terrestrial broadcasting system, we need a easy-to-use signal analysis and measurement system. The traditional signal measurement method is through the special hardware circuit to realize, but that method is high cost, and the system structure is complex and single function. To improve the flexibility of the system , we realize the system based on virtual instrument technology. In hardware section, this thesis described the block diagram of the system and the introduction of the NI vector signal analyzer. In software part, this thesis described the overall test system based on LabVIEW and the realization of the system features multi-threading, each step of synchronization signals achieved. The image Fig. 3 and Fig. 4 show the result of this system test software system.

Software Defined Modem for Cognitive Radio with Dynamically Reconfigurable Processor

Software Defined Radio (SDR) techniques are expected to be among the key technologies of heterogeneous cognitive radio networks for realizing efficient and convenient wireless communications by providing multiple radio services to users and decreasing development costs. In this paper, in order to evaluate the feasibility of SDR modems, we study the amount of computing throughput of a recent wireless system and determine a suitable modem architecture. Firstly, the functions for which SDR techniques provide significant benefits are clarified. Secondly, the computing throughputs are measured under the assumption that a dynamically reconfigurable processor, FlexSword™, is employed. Finally, based on a consideration of timing charts, we propose the architecture of an SDR-based modem with FlexSword. The possibility of implementing several wireless systems is also considered.

Use of Time-Frequency Analysis and Neural Networks for Mode Identification in a Wireless Software-Defined Radio Approach

The use of time-frequency distributions is proposed as a nonlinear signal processing technique that is combined with a pattern recognition approach to identify superimposed transmission modes in a reconfigurable wireless terminal based on software-defined radio techniques. In particular, a software-defined radio receiver is described aiming at the identification of two coexistent communication modes: frequency hopping code division multiple access and direct sequence code division multiple access. As a case study, two standards, based on the previous modes and operating in the same band (industrial, scientific, and medical), are considered: IEEE WLAN 802.11b (direct sequence) and Bluetooth (frequency hopping). Neural classifiers are used to obtain identification results. A comparison between two different neural classifiers is made in terms of relative error frequency.