Tobias Messinger

Multi-Gigabit Millimeter-Wave Wireless Communication in Realistic Transmission Environments

With the growing interest in millimeter-wave (mmW) communication links, especially for multi-gigabit backhaul applications, detailed studies on the performance limits in terms of achievable transmission distance and data rate, but also, and perhaps even more important, thorough investigations on the influence of different weather conditions gain in importance. In this paper we present a millimeter-wave monolithic integrated circuit (MMIC)-based transmit and receive front-end and ultra-broadband wireless data transmission experiments utilizing a 240 GHz carrier frequency in a long-range outdoor scenario as well as measurements inside a climatic wind tunnel. Data rates up to 64 Gb/s and various complex modulation formats are employed. While in the outdoor transmission, the link is tested in terms of maximum achievable transmission distance and data rate as well as alignment accuracy, in the climatic wind tunnel the influence of rain and fog in the transmission path is investigated in a defined and controlled environment.

Multi-gigabit E-band wireless data transmission

This paper presents the wireless data transmission of complex modulated signals in the E-band using a MMIC-based link compared to the current state of the art in millimeter-wave wireless communication. Highly linear and extremely broadband frontend components in combination with the latest equipment to generate and analyze broadband complex data signals are used in this experiment. The received signal quality is evaluated in terms of EVM and BER. An error free QPSK transmission with a data rate of 40 Gbit/s over a wireless distance of 6m is presented, while the transmission of 80 Gbit/s signals, achieved by 16-QAM modulation, results in a BER of 3.7 × 10-3.

Towards 100 Gbps Wireless Communication in THz Band with PSSS Modulation: A Promising Hardware in the Loop Experiment

Terahertz frequency band of 0.06 - 10 THz is especially interesting for ultra-high-speed wireless communication to achieve data rates of 100 Gbps or higher. To accommodate this demand, advanced terahertz signal processing techniques need to be investigated. Parallel Sequence Spread Spectrum (PSSS) is a physical layer (PHY) baseband technology that seems to be suited for being used for ultra-high speed wireless communication since the receiver architecture is especially simple and can be implemented almost completely in analog hardware. In this paper, a PSSS modulated signal at a chip rate of 20 Gcps with a spectral efficiency of (only) 1 bit/s/Hz is transmitted using a linearity limited 240 GHz wireless frontend. PSSS transceiver models are realized offline in MATLAB/Simulink. The PSSS transmitter generates the PSSS modulated symbols that are loaded onto an Arbitrary Waveform generator (AWG) and then transmitted using the available 240 GHz wireless frontend. A Digital Storage Oscilloscope (DSO) samples and stores the received signal. The PSSS receiver performs synchronization, channel estimation and demodulation. For a coded data rate of 20 Gbps, an eye opening of 40% and a BER of 5.4·10-5 has been measured. These results are highly promising to achieve data rates of up to 100 Gbps with PSSS modulation using a RF-frontend having higher linear operating range and thus allowing increasing the bandwidth efficiency to 4 b/s/Hz.

Multi-level 20 Gbit/s PSSS transmission using a linearity-limited 240 GHz wireless frontend

In this paper, we investigate the applicability of parallel sequence spread spectrum (PSSS) modulation in high bandwidth millimeter wave communication systems using a 240GHz monolithic microwave integrated circuit (MMIC) based radio frequency (RF) frontend. The transmitter (Tx) and receiver (Rx) are connected directly via an attenuator in an incoherent back-to-back setup using two independent local oscillator (LO) sources. Although the system was restricted to phase modulated signals due to limited linearity when using conventional modulated signals, a transmission using a multivalent PSSS sequence with a spectral efficiency of 1 bit/s/Hz succeeded thanks to the introduced coding gain. The recovered data is evaluated in terms of eye opening and bit error rate (BER). At a gross data rate of 20 Gbit/s, an eye opening of 40% and a BER of 5.4 × 10-5 were observed.

Divide-by-8 phase detector MMIC for PLL-based carrier recovery in E-band communication

A combined frequency divider and phase detector MMIC has been successfully realized in an GaAs mHEMT process with 100nm gate length, forming the base of a PLL carrier recovery for an E-band communication system. The frequency-divider-by-8 provides a sensitivity down to -54dBm - to the authors knowledge the highest sensitivity published in the E-band - and a bandwidth of 4.2GHz at a reference input power of -8 dBm. In an on-wafer measurement, the phase detector is measured with a detector gain of 293 mV/rad. In total, the IC draws a DC power of 734mW and measures 1.5 × 3.5 mm2.

Experimental validation of adverse weather effects on a 240 GHz multi-gigabit wireless link

The influence of hydrometeors on a MMIC-based wireless data transmission at 240GHz carrier frequency was experimentally evaluated in a climatic wind tunnel over a distance of 90 m. Successful transmissions of up to 24 Gbit/s QPSK modulated signals through heavy rain at 43 mm/h and dense fog at 3 g/m3 is achieved. The climatic impact is evaluated in terms of EVM. Reducing the bandwidth makes a transmission still possible with a BER <; 1 × 10-3 under conditions, where a free space optical link would fail.

Simulation of 100 Gbps using Parallel Sequence Spread Spectrum modulation (PSSS) with 240 GHz radio

This paper assesses the impact of the imperfections in radio components on the delay spread and bit error rate (BER) by simulating both analog and digital domains. Parallel Sequence Spread Spectrum (PSSS) is used for physical layer (PHY) baseband technology, which considerably alleviates both transmitter and receiver design. Authors investigate the performance of the PSSS systems using a 240GHz transmitter and receiver radio. In the Mililink project [1] the 240 GHz RF (Radio Frequency) front-end was developed. The RF front-end parameters like e.g. power amplifier, mixer, striplines and low noise amplifier have been used in our baseband simulation models to emulate radio impairment losses. The BER is simulated for the PSSS modulation with several cyclic prefix and spectral efficiencies.

Performance comparison of raised cosine shaped and rectangular pulsed signals in E-band wireless communication systems

A performance comparison of broadband complex modulated non return to zero raised cosine shaped and rectangular pulsed signals is analyzed on an all-electrical MMIC-based E-band wireless data transmission set up over a free space distance of 4.1 km. We successfully demonstrated a transmission of up to 12 Gbit/s in 4.05 GHz radio frequency bandwidth, whereat the difference between both pulse forms has been analyzed in terms of EVM and BER. Compared to a rectangular pulsed signal, a raised cosine filtered communication signal suffers more from linear and nonlinear effects caused by the transmission system due to inter symbol interference and stronger requirements on the exact sampling time.

A wideband phase detector SiGe HBT MMIC for multi-gigabit synchronous receivers

This paper reports a phase detector MMIC operating in the frequency range of DC to 40 GHz, with an average power conversion gain of 11 dB with wideband input matching. The MMIC is realized in 0.25 μm SiGe HBT technology. The phase detector is dedicated to form a Costas loop for broadband binary phase shift keyed signals.