| 1. |
- Chen, Jingjing, 1982, et al.
(författare)
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Demonstration of analog millimeter-wave fronthaul for 64-QAM LTE transmission
- 2015
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252.
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Konferensbidrag (refereegranskat)abstract
- Centralized baseband architecture is believed to be cost efficient and to offer high network performance. The fronthaul network, connecting the centralized baseband to distributed remote radios, requires high capacity and low latency transport links, due to the stringent specifications of the data interface, known as common public radio interface (CPRI). Today, fronthaul links are mostly based on digital CPRI over fibers, although it is possible to realize CPRI over wireless technology with the drawback of poor bandwidth efficiency. In this paper, we propose an analog wireless fronthaul concept to enable bandwidth efficient and scalable fronthaul networks. The basic idea is to transport narrow band analog radio signals over millimeter-wave bands instead of multi-gigabit digital signals. The phase and frequency impairments introduced by high frequency carriers are effectively reduced using an analog pilot-based mitigation technique. As a proof-of-concept demonstration, an analog fronthaul link is implemented, and the link performance is verified for 20 MHz 64-QAM LTE transmission over 70/80 GHz (E-band). The measured error vector magnitude (EVM) is about 3% with 10% pilot bandwidth overhead.
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| 2. |
- Rundstedt, Karl, 1990, et al.
(författare)
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On Field Measurements and Modelling of 2x2 Microwave LOS-MIMO Systems
- 2015
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Ingår i: Proceedings - IEEE Global Communications Conference, GLOBECOM. - 2334-0983 .- 2576-6813. - 9781479959525
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present channel measurementsand preliminary analyses from three 2x2 microwave Lineof-Sight Multi-Input Multi-Output (LOS-MIMO) outdoor test links, operating on 8 GHz and 32 GHz. The main focus of the measurement campaign is to study channel conditions and the effects of rain and clear-air fading. First, we address the diverse performance measures used in the trials. In particular we introduce the MIMO phase difference as an additional channel metric to the received power. The MIMO phase difference is mainly determined by antenna positions, ground effects and atmospheric variations. The relation between antenna positions and channel conditions was addressed in a number of earlier works, while the atmospheric impact and the resulting link availability are rarely studied. Second, we present the preliminary results from the long-term measurement campaign. The longterm statistics of channel condition from the three links show stable performance. Analysis reveals that fluctuation of the phase difference and the channel condition number is likely due to abnormal atmospheric propagation which can be modelled using a two-ray reflection model. Meanwhile, rain attenuation is strongly correlated between MIMO sub-channels and its contribution to the long-term statistics of power loss is very close to the Single-Input Single-Output (SISO) case.
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