The design methodology and circuit implementation of a transimpedance (TI) amplifier (TIA) featuring low averaged input-referred current noise density without compromising the TIA bandwidth (BW) are presented. The technology role in the key performance metrics is also discussed and verified by means of two analogous TIA designs implemented in two different 130-nm SiGe:C BiCMOS processes from IHP, SG13S with $f_{T}/f_{\max }= 250/340$ GHz and SG13G2 with $f_{T}/f_{\max }= 300/500$ GHz. Both TIAs adopt a fully differential linear architecture with three stages: an input shunt-feedback TI stage followed by a variable gain amplifier which provides post-amplification with 15-dB gain control range and an output 50- $\Omega $ buffer. The TIA in SG13S features 68.5 dB $\Omega $ differential TI gain, 42-GHz 3-dB BW, and 8 pA/ $\sqrt {\mathrm {Hz}}$ averaged input-referred current noise density while the second TIA in SG13G2 provides 65 dB $\Omega $ differential TI gain, 66-GHz 3-dB BW, and 7.6 pA/ $\sqrt {\mathrm {Hz}}$ . Measured total harmonic distortion in both TIAs in the maximum gain condition is better than 5% for ~800 mVppd output swing and input currents of ~300 $\mu $ App. Both circuits dissipate 150 mW of power and are shown to operate at up to 100 Gb/s data rate with clean PRBS31 non-return to zero and PAM-4 eye diagrams. To the author’s best knowledge, the reported TIAs exhibit the lowest averaged input-referred current noise density shown to date at a BW sufficient to support 100 Gb/s net data rate, surpassing other silicon-based and InP implementations toward the next-generation 400 Gb/s optical links.

This article presents the deployment and experimentation architecture of the Aveiro Tech City Living Lab (ATCLL) in Aveiro, Portugal. This platform comprises a large number of Internet-of-things (IoT) devices with communication, sensing and computing capabilities. The communication infrastructure, built on fiber and Millimeter-wave (mmWave) links, integrates a communication network with radio terminals (WiFi, ITS-G5, C-V2X, 5G and LoRa(WAN)), multiprotocol, spread throughout 44 connected points of access in the city. Additionally, public transportation has also been equipped with communication and sensing units. All these points combine and interconnect a set of sensors, such as mobility (radars, light detection and rangings (LiDARs), video cameras) and environmental sensors. Combining edge computing and cloud management to deploy the services and manage the platform, and a data platform to gather and process the data, the living lab supports a wide range of services and applications: IoT, intelligent transport systems (ITSs) and assisted driving, environmental monitoring, emergency and safety, among others. This article describes the architecture, implementation and deployment to make the overall platform to work and integrate researchers and citizens. Moreover, it showcases some examples of the performance metrics achieved in the city infrastructure, the data that can be collected, visualized and used to build services and applications to the cities, and, finally, different use cases in the mobility and safety scenarios.

In this paper, a monolithically integrated segmented linear driver and Mach-Zehnder modulator (MZM) are presented. The transmitter is fabricated in electronic-photonic integrated circuit 0.25-μm SiGe:C BiCMOS technology, with f _T /f _max = 190 GHz. The driver and the modulator are divided into 16 segments and the MZM phase shifter has a total length of 6.08 mm. The segmented driver delivers a maximum of 4 V _pp differentially, featuring a gain of 13 dB and total harmonic distortion below 5%. Electro-optical time-domain measurements using PAM-4 modulation format are performed, demonstrating optical eye-diagrams up to 25 Gbaud. The electro-optical bandwidth of the transmitter is 18 GHz. The power dissipation of the driver is 1.5 W, resulting in an energy per bit of 30 pJ/bit at 50 Gb/s. The reported optical transmitter demonstrates for the first time an implementation of a linear driver integrated with an MZM in a Si monolithic process.

Most fatal road accidents in urban areas involve vulnerable road users. New solutions for fighting against these accidents can be considered by leveraging connected, intelligent vehicles and smart cities connecting all parts of an urban environment. This work proposes a multi-sensing and communication approach to prevent potential accidents between vehicles and VRUs, by predicting and notifying both about potential collisions before they happen. This approach leverages and aggregates information from smart city sensors, dispersed in the vehicles (and aggregated by the On-Board Units, OBUs), in the VRUs (e.g., smartphones and smartwatches), and on the road itself (e.g. video cameras, radars, lidars). These elements communicate through several message standards and wireless access technologies (e.g. ITS-G5, C-V2X, LTE, 5G and, in the future, 6G). Using both sensing and communication, fusion and collision detection algorithms, this system predicts and notifies potential hazardous situations involving Vulnerable Road User (VRU)s and vehicles. The results in a real scenario with sensors, VRUs and vehicles on the road show that the system predicts potential collisions with high accuracy and low delay. Results also point to some vital deployment decisions that must be made to ensure proper notification timings, such as the usage of multi-homing, 5G and edge computing.

In this paper, a linear driver for optical modulators in a 0.13- $\mu \text{m}$ SiGe:C BiCMOS technology with $f_{T}/f_{\text {max}}$ of 300/500 GHz is presented. The design is implemented following a distributed amplifier topology in a differential manner. The driver features a small-signal gain of 12.5 dB and a 3-dB bandwidth of 90 GHz and delivers a maximum output amplitude of $4~V_{\text {pp}}$ to a 100- $\Omega $ differential load. Delivering the maximum output swing, the large-signal gain is 10.5 dB. Time-domain measurements are performed, showing the maximum output swing with ON–OFF keying (OOK) eye-diagrams up to 64 Gb/s and pulse amplitude modulation-4 up to 45 Gbaud (90 Gb/s). Moreover, OOK eye-diagrams up to 120 Gb/s are reported with an output swing of $3~V_{\text {ppd}}$ . Total harmonic distortion measurements are also conducted demonstrating a value of 5% at 1 and 8 GHz up to an input amplitude of 800 mV_ppd. Using a reduced number of stages in the design, the power dissipation of the integrated circuit is 550 mW, resulting in an output power to power dissipation ratio of 3.6%. To the best knowledge of the authors, this is the first time a linear driver for optical modulators demonstrates such high bandwidth and efficiency for the demonstrated data-rates.

The Industrial Internet of Things (IIoT) is one of the most demanding IoT applications. The insertion of industries in the context of smart cities and other smart environments, allied with new communication technologies such as 5G, brings a new horizon of possibilities and new requirements. These requirements include low latency, the support of a massive quantity of devices and data, and the need to support horizontal communications between devices at the edge level. To make this feasible, it is necessary to establish an IIoT-to-cloud continuum distributing federated brokers across the infrastructure and providing scalability and interoperability. To attend this type of application, we present the Helix Multi-layered IoT platform and its operating modes. We report and discuss its real-world deployment in the Aveiro Tech City Living Lab in Aveiro, Portugal with functional and performance tests. We tested device-to-device communication across edge and core layers and also interconnected the infrastructure with one in São Paulo, Brazil, replicating the use of a global industry. The successful deployment validates the use of a Helix Multi-layered IoT platform as a suitable backend platform for IIoT applications capable of establishing the IIoT-to-cloud continuum. It also helps for the deployment of other applications in such a domain.