Baseband Signal Generation Research Articles

Design of a Baseband Signal for the 406 MHz Satellite Emergency Radio Transmitter Based on STM32

The baseband signal of the 406 MHz COSPAS-SARSAT emergency beacon is a 144-bit or 112-bit data with 0 and 1 code, including the information bits and error correcting check bits. In order to improve the coding efficiency of the baseband signal for the 406 MHz transmitter in the STM32 micro-controller, this paper proposes a calculation method for the first BCH error correcting code (BCH-1) and the second BCH error correcting code (BCH-2) of the COSPAS-SARAST transmitter. First, conduct the data coding process by 64-bit integral data; then, compute the BCH (127, 106) code and the BCH (63, 51) code to obtain the respective error correcting codes for improving coding rate; next, generate the baseband signal according to the GB 14391-2021 coding format; finally, modulate the baseband signal into a 406 MHz-RF signal, send it out and complete the task of distress alerting. The experimental results show that the proposed STM32 microcontroller-based baseband signal generation method is effective, and the EPIRB (Emergency Position Indicating Radio Beacon) designed based on this method has reached the industry standard.

(Digital Presentation) Sub-THz Front Ends for Future Communication and Sensing Technologies in 130nm Sige Bicmos Technology

Introduction: Beyond the-5G technologies are targeting the available bandwidth (BW) in the D-band and J-band. This promises for very high speed communication and sensing accuracy. Although the advantages of operating beyond 100 GHz from the application point of view, it requires a lot of research and development to design a reliable and power efficient chipsets. In this presentation we will go through the design of wideband 240 GHz transmitter (Tx) and receiver (Rx). Firstly an overview about the link budget analysis will be given, then the design of the local carrier signal generator will be discussed. The wideband Txs and Rxs are to be presented with frequency channelizing concept. At the end the results of the wireless links will be demonstrated. Link Budget Analysis: Operating at sub-THz frequencies approaching the transistor fT put a lot of constraints on the system link budget. The elevated noise figure together with the limited maximum Pout of the transistors lead to solutions which might be limited in BW or power efficiency. Hence the design architecture need to be optimized taking into account the elevated power consumption and heat dissipation. Carrier Generation: Several approaches could be followed to generate the sub-THz carrier frequency. For a power efficient solution the fundamental oscillators promise for a power efficient solution but with limited phase noise performance and tuning range. Such a solution is more common for imaging systems operating at a single frequency. In order to achieve wider tuning ranges for multi-channel scenario or FMCW radar systems, the frequency multiplication chains are common, whereas the multiplication factor depends on the system parameters. Sub-THz Rx: Different approaches were followed to realize a wideband sub-THz Rx. For some technologies the transistors ft does not promise the realization of low noise amplifiers (LNA) with reasonable noise figure, gain and BW. Hence the mixer first approach were followed trying to optimize the noise figure of the down conversion mixer as much as possible. This also enhances the input compression point (IP1dB) of the Rx which is better for monostatic radar applications. On the other hand, if the technology in use allows the development of well performing LNA’s, the LNA first approach was followed to enhance the all over NF of the receiver and ease the implementation of IQ Rxs. In our work an LNA was implemented followed by IQ downconversion mixers and baseband chain as presented in [3]. Sub-THz Tx: The Tx main challenging performance parameter in the sub-THz frequency range is to achieve high output compression point across the required BW with as high efficiency as possible. Increasing the power handling capabilities of the power amplifiers (PA) by increasing the transistors sizes of the output stages, leads to low output impedance and hence higher impedance transformation ratios for the matching structures and eventually narrow band designs. Hence the power combining architectures were proposed as an alternative to increase the output power either by combining on-chip or combining in air. In this work a fully integrated IQ Tx is to be presented with on-chip LO chain and 4-way power combined power amplifier. Baseband Signal Generation and Processing The baseband topology depend on the application. For mobile communication or localization use cases a wideband channels are not available directly from the digital processors, a kind of channel bonding is required either in the digital domain or in the analog domain. As a proof of concept we present here 3-IQ frequency interleaving combiner. Wireless Link Demonstrator Two demonstrators are to be presented. The first demonstrator is transmitting a broadband IQ signal generated from an arbitrary wave generator wirelessly utilizing an IQ 240GHz Tx and Rx. Data rates up to 100 Gbps were demonstrated across a 1m of wireless link. The second demonstrator includes the implementation of 3-channel IQ channelizer to create the complex modulated signal at several intermediate frequencies (IFs) and then upconverted to the 240GHz carrier signal. On the Rx side the de-channelizer convert the down modulated signal to three IQ channels. Data rates up to 8Gbps were demonstrated wirelessly with the channelization with potential of further enhancements for more channels integration. Outlook The future of the sub-THz wireless links for high speed communication and localizations goes towards implementing phased array and MIMO systems. This requires the research community to develop novel architectures to develop large scale arrays with acceptable power consumptions and suitable packaging solution. On the baseband side also the channel bonding solutions are still in an early stage, requiring more work to bond modularly larger number of channels.

A PRACH Preamble Generation and Detection Model for 5GNR Systems

The basic idea of 5th generation New Radio (5GNR) is to have very high data rate and to make it work efficiently for all Internet of Things (IOT) applications like healthcare, Automotive, Industrial etc. applications. This paper provides the Orthogonal Frequency Division Multiple Access (OFDM) baseband signal generation and detection method for Physical Random-Access Channel (PRACH). The proposed model provides four scenarios of preamble detection i.e., Preamble detection probability, Miss-detection probability, False alarm probability and null. We achieved the target of 99% of Probability of Detection and less than 0.1% of False-alarm probability at certain SNR as specified according to 3gpp standard requirements when tested in Additive White Gaussian Noise (AWGN) channel and Extended Typical Urban (ETU) channel.

Baseband Signal Generation for Multi-Function Phased Array Radar

The multi-function phased array radar (MPAR) is used for weather monitoring, air-traffic control requirements and non-cooperative elements monitoring in a parallel manner. The amplitude of the radio frequency signal is varied depending on the location of the target from the radar. The proposed work generates a signal which is used as a input for RF transmitter of Multifunction Phased Array Radar. To achieve this MPAR requirement, the in-phase and quadrature-phase samples are generated for a high data rate using MATLAB and then VHDL output was obtained from Xilinx for QPSK and QAM modulation techniques.

Software-Defined Radio Transceiver Design Using FPGA-Based System-on-Chip Embedded Platform With Adaptive Digital Predistortion

In this paper, a software-defined radio (SDR) based transceiver system is designed and implemented on the system-on-chip (SoC) platform, which consists of a high-speed Arm embedded processor and a reconfigurable field-programmable gate array (FPGA). In the proposed SDR transceiver, the real-time baseband signal generation and adaptive digital predistortion (ADPD) units are implemented on the SoC platform. Memory polynomial model based ADPD solution is implemented to linearize the radio frequency (RF) power amplifiers (PAs). The implementation of the ADPD on a reconfigurable FPGA platform makes the system flexible and cost-effective. The PA characterization, in terms of model extraction and coefficient calculation, is done in real-time. These calculated coefficients are updated in the transmission path to precondition the transmitted signal before it is applied to the PA. The proposed ADPD is applied at the baseband level. Therefore, it can be used for different classes of PA operating at different RF carrier frequencies. A long-term evolution (LTE) signal with 20 MHz bandwidth and 11 dB peak to average power ratio (PAPR) is used for simulation and measurement purposes. The LTE signal is amplified using a GaN-based harmonically tuned continuous Class-F PA in measurement. The performance of the implemented ADPD scheme is analyzed in terms of NMSE, ACPR and EVM.

Reconfigurable Architecture of UFMC Transmitter for 5G and Its FPGA Prototype

A universal-filtered multicarrier (UFMC) system that is a generalization of filtered orthogonal frequency-division multiplexing (OFDM) and filter-bank-based multicarrier is being considered as a potential candidate for fifth-generation due to its robustness against intercarrier interference as in cyclic-prefix-based OFDM systems. However, real-time hardware realization of multicarrier systems is limited by a large number of arithmetic units for inverse fast Fourier transform and pulse-shaping filters. In this paper, we aim to propose a low-complexity and reconfigurable architecture for a baseband UFMC transmitter. To the best of our knowledge, the proposed architecture is the first reconfigurable architecture that has the flexibility to choose the number of subcarriers in a subband without any change in hardware resources. In addition, the proposed architecture selects the filter from a group of filters with a single selection line. Moreover, we use a commercially available field-programmable gate array device for real-time testing and analyzing the baseband UFMC signal. From the extensive experiments, we study the occupied bandwidth, main-lobe power, and sidelobe power of the baseband signal with different filters in real-time scenarios. Finally, we measure the quantization error in baseband signal generation for the proposed UFMC transmitter architecture and find comparable with the error bound.

Wideband signal transceiver module with a Doppler shift function.

The wideband signal transceiver module forms the core component of the radar signal target simulator and the key module in measuring the Doppler shift. In this paper, we present a design for a miniaturized wideband signal transceiver module based on a PXIe bus, with an operating frequency range of 65 MHz-3 GHz, an instantaneous measurement bandwidth of 800 MHz on a standard 3U (where 1U = 4.445 cm) board with three slots. The module adopts a zero intermediate frequency transceiver, and the baseband uses two analog to digital converters, a field programmable gate array, and two digital to analog converters as the core hardware architecture. The module combines key technologies including variable-frequency local oscillator synthesis, radio-frequency broadband signal conditioning, and high-speed high-resolution baseband signal acquisition and generation. This paper describes a novel design for the Doppler shift function. Considering the limited size and volume of the module, Doppler shift technology combining a complex signal and a real signal was adopted to achieve full band coverage with an operating frequency range of 65 MHz-3 GHz. We verified that this module could generate the Doppler shift in the frequency band from -400 Hz to 400 Hz in steps of 2 Hz and with an error of ±2 Hz.

Research on the DFT of ZC Sequence in TD-LTE System

In the LTE system, Zadoff---Chu (ZC) sequence is used for the generation and detection of physical random access channel (PRACH) preamble sequence. The key step of PRACH baseband signal generation ...

실시간 GNSS 기만 시뮬레이터를 이용한 위성항법수신기에서의 기만 영향 분석

In this paper, spoofing effects on a GNSS receiver were analyzed. The spoofer (spoofing device) was classified to two categories. One is an active spoofer and the other is a passive spoofer. The active spoofer was considered for analysis. For the analysis of spoofing effects on a GNSS receiver, a real-time GNSS spoofing simulator was developed. The simulator was consisted with two parts which are a baseband signal generation part and a RF up-conversion part. The first GNSS baseband signal was generated according to spoofing parameters such as range, range rate, GNSS navigation data, spoofing to GNSS signal ratio, and etc. The generated baseband signal was up-converted to GNSS L1 band. Then the signal transmitted to a GNSS signal. For a perfect spoofing, a spoofer knew an accurate position and velocity of a spoofing target. But, in real world, that is not nearly possible. Although uncertainty of position and velocity of the target was existed, the spoofer was operated as an efficient jammer.

A Very Low-Complexity 0.3–4.4 GHz 0.004 mm$ ^{2}$ All-Digital Ultra-Wide-Band Pulsed Transmitter for Energy Detection Receivers

This paper presents a very low-complexity all-digital IR-UWB transmitter that can generate pulses in the band 0-5 GHz, requiring a silicon area lower than a PAD for signal I/O. The transmitter, suited to non-standardized low data rate applications, is prototyped in a 130 nm RFCMOS technology and includes analog control signals for frequency and bandwidth tuning. Center frequency is linearly selected with voltage supply, 0.5 V for the range 0-960 MHz and 1.1 V supply for the higher 3.1-5 GHz range. The architecture is based on the same delay cell for both baseband and radio frequency signal generation and pulses fractional bandwidth remains constant when voltage supply and control voltages scale. At 420 MHz center frequency, the transmitter achieves 7 pJ/pulse, and for 4 GHz center frequency pulses, it achieves 32 pJ/pulse active energy consumption. The OOK/S-OOK transmitter occupies an area of 0.004 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . For ASK modulation, the system includes a separate on-chip capacitor bank connected to the output of the transmitter for an overall size of 0.024 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . For pulse rates below 100 kpps, the generated pulses meet the FCC indoor mask with an off-chip DC block capacitor. The paper also presents over-the-air measurements using a planar monopole antenna operating in the 1.5-3.7 GHz frequency range.

Design of a Baseband Signal Generator in Navigation Satellite Signal Simulators

To improve simulation precision, the signal model of navigation satellite signal simulators is illustrated, and the generation mechanism and evaluation criteria of an important error source-phase jitter in baseband signal generation, are studied subsequently. An improved baseband signal generator based on dual-ROM look-up table structure is designed with the application of a newly-established concept-virtual sampling rate. Pre-storage of typical baseband signal data and sampling rate conversion adaptive to Doppler frequency shifts are adopted to achieve the high-precision simulation of baseband signals. Performance analysis of the proposed baseband signal generator demonstrates that it can successfully suppress phase jitter and has better spectral performance, generating high-precision baseband signals, which paves the way to improving the overall precision of navigation satellite signal simulators.

Multiband Signal Generation and Dispersion-Tolerant Transmission Based on Photonic Frequency Tripling Technology for 60-GHz Radio-Over-Fiber Systems

We designed and experimentally demonstrated an efficient photonic frequency-tripling technology for 60-GHz radio-over-fiber systems to simultaneously realize millimeter-wave (mm-wave), microwave, and baseband signal generation. The technique utilizes vestigial sideband filtering in combination with optical carrier suppression to generate novel alternate subcarrier modulation for high tolerance of fiber dispersion. Experimental verification of the proposed scheme is presented with generation and error-free transmission of 2.1-Gb/s data on the 63-GHz mm-wave and 21-GHz microwave carriers over 50-km single-mode fiber (SMF-28) without dispersion compensation. The power penalty for both signals is less than 1.0 dB.

A 2.7-V CMOS single-chip baseband processor for CT2/CT2+ cordless telephones

A low-voltage, low-power CMOS single-chip baseband processor for CT2 and CT2+ cordless telephones is presented. The chip integrates a complete voiceband codec, a tone generator, a G721 adaptive differential pulse code modulation coder/decoder, a burst-mode logic controller for CT2/CT2+ framings, and an I/Q baseband signal generator. The only external components are made of two quartz crystals. The chip is interfaced with standard microcontrollers through a parallel interface. With a 2.7 V minimum supply, it consumes normal and standby powers of 35 mW and 25 /spl mu/W, respectively. Maximum supply is 5.5 V, and temperature range is from -40 to 70/spl deg/C. Chip area (including scribe line) is 55.5 mm/sup 2/ in a 0.8 /spl mu/m N-well double-metal single-poly CMOS process with implanted capacitors.