An All-Digital, Single-Bit RF Transmitter for Massive MIMO

Markert, Daniel; Yu, Xin; Heimpel, Holger; Fischer, Georg

doi:10.1109/tcsi.2016.2615161

Cited by 31 publications

(14 citation statements)

References 20 publications

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“…But due to the non linearity in the ∆Σ loop, typical loop unrolling techniques used in digital signal processing can no longer be exploited. A third option is explored in [10], here a hybrid implementation combining the advantages of PWM and ∆Σ modulation is proposed, i.e. high coding efficiency and a good ACPR.…”

Section: A Single-bit All-digital Modulatormentioning

confidence: 99%

“…high coding efficiency and a good ACPR. In [10], the authors observe that the general method for encoding a complex baseband signal to a binary pulse sequence is to map the carrier frequency (f c ) to the pulse repetition rate, the phase to the pulse position and the amplitude to the pulse width. Fig.…”

Section: A Single-bit All-digital Modulatormentioning

confidence: 99%

“…To allow real-time modulation of an all-digital RF transmitter, [10] combines delta-sigma modulation and pulsewidth modulation. In this paper, we present a real-time all-digital radio-over-fiber link consisting of a digital transmitter which modulates a VCSEL using the aforementioned algorithm and an analog RoF receiver.…”

Section: Introductionmentioning

confidence: 99%

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Real-time all-digital radio-over-fiber LTE transmission

Kerrebrouck

Breyne

et al. 2017

2017 Advances in Wireless and Optical Communications (RTUWO)

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Abstract-Radio-over-fiber is a key-enabling-technology for next generation wireless networks. To support an increasing number of antennas, a CloudRAN approach that maximally aggregates base station functionality of the different antenna sites is the most economically feasible. To support light weight antenna units, analog radio-over-fiber is most promising. To mitigate linearity constraints of optical modulators, an all-digital transmitter can be used. In this paper, LTE transmission is demonstrated over 200 m OM4 multimode fiber using a VCSEL and a resonant transimpedance amplifier. The VCSEL is directly modulated with a high-speed 2-level signal generated in real-time on an FPGA. After reception of this signal, the adjacent channel power ratio was measured to be -45.6 dB. This is within the LTE specifications, proving this is a cost and power effective solution for next generation wireless networks.

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Section: A Single-bit All-digital Modulatormentioning

confidence: 99%

Section: A Single-bit All-digital Modulatormentioning

confidence: 99%

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Real-time all-digital radio-over-fiber LTE transmission

Kerrebrouck

Breyne

et al. 2017

2017 Advances in Wireless and Optical Communications (RTUWO)

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“…digital communication with a simple, power efficient RRH while completely eliminating the need for high-speed, high resolution DACs is provided by sigma delta-over-fiber (SDoF) [6], [7], [8] and as shown in Fig. 1c.…”

Section: Introductionmentioning

confidence: 99%

“…This results in a NTF magnitude below -40 dB over 200 MHz around the 1 GHz center frequency and a STF magnitude around -8 dB over the same frequency band, assuming the sample rate is at least 8 Gbps. FPGA and ASIC implementations of sigma delta modulators running at very high rates have already been demonstrated [8].…”

Section: Introductionmentioning

confidence: 99%

Comparison Between Analog Radio-Over-Fiber and Sigma Delta Modulated Radio-Over-Fiber

Breyne

Torfs

Yin

et al. 2017

IEEE Photon. Technol. Lett.

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Abstract-With the continuously increasing demand of cost effective, broadband wireless access, radio-over-fiber (RoF) starts to gain more and more momentum. Various techniques already exist, using analog (ARoF) or digitized (DRoF) radio signals over fiber. Each with their own advantages and disadvantages. By transmitting a sigma delta modulated signal over fiber (SDoF), a similar immunity to impairments as DRoF can be obtained while maintaining the low complexity of ARoF. This letter describes a detailed experimental comparison between ARoF and SDoF that quantifies the improvement in linearity and error vector magnitude (EVM) of SDoF over ARoF. The experiments were carried out using a 16QAM constellation with a baudrate from 20 to 125 Mbaud modulated on a central carrier frequency of 1 GHz. The sigma delta modulator (SDM) runs at 8 or 13.5 Gbps. A high speed VCSEL operating at 850 nm is used to transmit the signal over 200 m multimode fiber. The receiver amplifies the electrical signals and subsequently filters to recover the original RF-signal. Compared to ARoF, improvements exceeding 40 dB were measured on the third order intermodulation products when SDoF was employed, the EVM improves between 2.4 to 7.1 dB.

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