Robust Optical Wireless Link for the Backhaul and Fronthaul of Small Radio Cells

This paper summarizes recent work on the use of optical wireless links as a robust outdoor backhaul solution for small radio cells, such as WiFi, LTE and 5G, over distances between 20 and 200 m. Results of a 5-month outdoor field trial in Berlin, Germany, indicate that the visibility range was never below 180 m, with more than 1 km in 99% of all times during this period. Rate-adaptive transmission proved to improve the availability remarkably in the occasional presence of fog or sunlight. A mathematical model of the backhaul link including these impairments is presented and implemented to obtain an optimized link design. A prototype was realized, accordingly, using low-cost optoelectronic components and a 1 Gb/s baseband chipset. Gross data rates of 800, 500, and 225 Mb/s have been achieved in real-time operation over 20, 100, and 215 m outdoor link distance, respectively, with 2 ms latency at 95% load. Finally, we discuss further evolution towards 5G mobile networks.

[1]  Sevia Mahdaliza Idrus,et al.  Optical Wireless Communications: IR for Wireless Connectivity , 2008 .

[2]  Volker Jungnickel,et al.  Fronthaul evolution: From CPRI to Ethernet , 2015 .

[3]  V. Jungnickel,et al.  Optical wireless communication for backhaul and access , 2015, 2015 European Conference on Optical Communication (ECOC).

[4]  Volker Jungnickel,et al.  Initial Outdoor Trials with Optical Wireless Links for Small-Cell Backhauling , 2015 .

[5]  Volker Jungnickel,et al.  Rate-adaptive visible light communication at 500Mb/s arrives at plug and play , 2013 .

[6]  Tommy Svensson,et al.  The role of small cells, coordinated multipoint, and massive MIMO in 5G , 2014, IEEE Communications Magazine.

[7]  Volker Jungnickel,et al.  Convergent radio and fibre architectures for high-speed access , 2013, 2013 15th International Conference on Transparent Optical Networks (ICTON).

[8]  Volker Jungnickel,et al.  High-speed visible light communication systems , 2013, IEEE Communications Magazine.

[9]  Philip C. D. Hobbs,et al.  Building electro-optical systems , 2000 .

[10]  Hunsperger.  Photonic Devices and Systems , 1994 .

[11]  Volker Jungnickel,et al.  Adaptive Modulation and Turbo Coding for 3GPP LTE Systems with Limited Feedback , 2014, 2014 IEEE 79th Vehicular Technology Conference (VTC Spring).

[12]  A. Prokeš.  Modeling of Atmospheric Turbulence Effect on Terrestrial FSO Link Aleš PROKEŠ , 2009 .

[13]  M. Uysal,et al.  Novel Adaptive Transmission Algorithms for Free-Space Optical Links , 2012, IEEE Transactions on Communications.

[14]  Michael Schlosser,et al.  Low Latency Mobile Backhauling using Optical Wireless Links , 2015 .

[15]  Michael Schlosser,et al.  Optical wireless LED link for the backhaul of small cells , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[16]  Frank Schaich,et al.  Quantitative analysis of split base station processing and determination of advantageous architectures for LTE , 2013, Bell Labs Technical Journal.

[17]  Isaac I. Kim,et al.  Comparison of laser beam propagation at 785 nm and 1550 nm in fog and haze for optical wireless communications , 2001, SPIE Optics East.