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The application of high-count multi carrier optical sources (i.e. frequency combs) in real-time microwave/millimeter wave signal processing is discussed. The multi heterodyne sensing and classification of up to 110 GHz-wide radio frequency (RF) signals using two set of optical frequency combs is demonstrated.
This paper presents a fully-integrated direct-conversion fundamentally-operated mixer-first quadrature receiver chip working at 240 GHz. It has been implemented in a 0.13-μm SiGe HBT technology with fT/fmax of 350/550 GHz. The chip includes an LO path based on a x16 multiplier with a 3-stage PA, driven externally from the PCB at 14–18 GHz. The LO signal is split in quadrature by a broadband coupler...
This paper describes a method to increase the sensitivity of a digital radio receiver based on the time synchronous averaging (TSA). The data to be send are grouped into a block and the block is retransmitted multiple times. Received blocks are synchronously averaged thus increasing the signal-to-noise ratio. The TSA can be performed on the analog signal at the demodulator output (soft TSA) or on...
This paper explores an interleaving approach to expand the effective sampling rate of analog-to-digital converters (ADCs) with application to power amplifier characterization and digital pre-distortion. By interleaving a known test signal, it is shown that a 250 MSPS ADC can be used to effectively sample at 2 GSPS, providing 1 GHz of observational bandwidth. A 200 MHz “stretched” LTE signal is then...
Photonic weight banks employing multivariate statistical techniques could extend performance limits of multiantenna radio systems. We characterize the aggregate bandwidth penalty imposed by a silicon microring weight bank and assess application regimes for multivariate RF photonics.
The IEEE 802.22 system was standardized in 2011 as a fixed wireless communication system for regional area networks using TV white-spaces (TVWS). Due to its wide coverage area of 10–30 km, the IEEE 802.22 system is expected as a backbone wireless network system in developing countries as well as a public safety broadband communication system even in leading countries. This wide coverage enables a...
This paper presents a wideband blocker-tolerant Direct ΔΣ receiver (DDSR). Blockers are attenuated through selective input impedance matching and optimized gain design. The created impedance profile provides low receiver input impedance at blocker frequencies, while at desired frequencies, the impedance is boosted to matched condition through an up-converted positive feedback from the DDSR output...
5G backhaul requires high bandwidth and hybrid Radio Frequency/ Free Space Optical (RF/FSO) Communication offers Gbps links. The weather affects availability of both mmW RF and FSO links. Below cloud ceiling, the availability of hybrid RF/FSO link is above 85.7% and it can only be used for deadline-constrained large data transfers. At 17–22km above ground, the bit error rate of FSO links reaches below...
An interference monitoring station is presented which detects, characterises and logs interference events. The system operates autonomously and continuously over multiple global navigation satellite system (GNSS) bands. With a bandwidth of up to 80 MHz, input resolution of 8 bit an overall data rate of approximately 1.3 Gbit/s can be supported. The interference detection is carried out in real-time,...
Recent broadcast standards support Layered Division Multiplexing (LDM) to achieve graceful degradation as signal quality degrades at the receiver. LDM is accomplished by using different constellations within the same Radio Frequency (RF) spectrum. LDM thus enables delivering multiple service tiers in a single broadcast channel. LDM when used in conjunction with scalable source coding codecs such as...
Carrier aggregation supports an increased total bandwidth, data rate and utilization of available fragmented spectrum, where the latter is a core component of next generation Wi-Fi and Cellular networks, including 5G. Wireless communications receivers with intra-band non-contiguous CA, employing conventional complex mixers and base-band circuitry, are desirable, however risks of VCO injection pulling...
This paper presents a low cost OFDM based channel sounding technique which can be implemented on a low power embedded system. The technique is first used to measure the channel of an indoor environment and is validated by comparison with a VNA and a ray-tracing simulator. We then show its usage in two interesting situations. Finally, we conclude the paper by giving the advantages and drawbacks of...
Flight inspection of radio-based terrestrial navigation systems is crucial for sufficient accuracy. Especially in proximity of wind turbines (WT), which have arisen in recent years due to government subsidies for renewable energies, flight inspections must be carried out. This causes problems that hinder the usage of conventional aircraft: Even rotorcraft (e.g. helicopters) require a certain amount...
This paper discusses the influence of non-idealities in the analog transmit and receive frontend of an MMIC-based 300 GHz wireless link on the receive signal quality. The degradation of EVM due to limited bandwidth and gain imbalance in the quadrature up- and down-converters is considered and compared to experimentally achieved data. Using adaptive equalization and quadrature error correction in the...
Wake-up receivers (WuRXs) are low-power radios that continuously monitor the RF environment to wake up a higher-power radio upon detection of a predetermined RF signature. Prior-art WuRXs have 100s of kHz of bandwidth [1] with low signature-to-wake-up-signal latency to help synchronize communication amongst nominally asynchronous wireless devices. However, applications such as unattended ground sensors...
Ultra-narrow-band (UNB) signaling is an enabling technology for low-power wide-area (LPWA) networks for the “Internet-of-Things”. Indeed, UNB signaling, based on spectrally efficient modulations such as DBPSK, simultaneously optimizes network capacity while maximizing the communication link budget. However, UNB signaling poses many technical challenges. In the receiver, carrier frequency offsets (CFO)...
A combination 95 GHz radar and 270/560 GHz spectrometer is being built as a space instrument prototype for probing plumes and jet phenomena in the solar system. Dubbed GAISR (Gas And Ice Spectrometer/Radar), the instrument's radar will make simultaneous range/Doppler measurements of 0.1–10 mm sized ice and dust particles out to a few km in range, while its tunable spectrometer will detect the abundance...
Over the past twenty years or so there has been much interest in the use of digital pre-distortion techniques for the linearization of RF and microwave power amplifiers. This paper presents a snapshot of the current challenges posed by demands for wider bandwidth and lower power consumption, and some potential solutions.
The paper reviews our recent experimental work in the area of multi-Gigabit fixed wireless links operating in the high millimeterwave frequency range. An E-band link is employed to transmit up to 6 Gbit/s over a line-of-sight terrestrial distance of 36.7 km using QPSK modulation, and 15 Gbit/s over 15 km using 8QAM. At 240 GHz, up to 64 Gbit/s QPSK are transmitted over a distance of 850 m. The paper...
The multi-copy routing paradigm in Delay Tolerant Networks (DTNs) implies that increasing contact bandwidth leads to a decrease in data delivery delay and an improvement in throughput. With Hybrid Radio Frequency/Free Space Optical (RF/FSO) PHY layers, the high data rate FSO links can be used to increase the contact bandwidth. However, due to the highly directional nature of FSO links, broadcasting...
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