Tessco Wireless Journal February March 2015 Page 3 TESSCO Wireless Journal February-March 2015

See TESSCO's entire product offering and your pricing on www.tessco.com or call TESSCO at 800.472.7373. 3 February/March 2015 The New Backhaul Challenge Wireless connectivity is a reality in enterprise today. As users require more access to mobile technologies, networks become denser and more complex, and IT managers face chal- lenges with backhaul. Add to that topography and environmental dynamics, and direct line- of-sight (LOS) does not always exist between nodes. Common methods to compensate for lacking LOS include passive reflectors and repeaters or even daisy chaining. These are not always effective resolutions to the chal- lenge and create a need for near- and non- line-of-sight (NLOS) microwave backhaul. Breaking the Myth The traditional belief in the telecom industry is that sub-6 GHz frequencies are required to ensure performance in locations where NLOS conditions exist. One problem is that the avail- able spectrum below 6 GHz is very limited and is insufficient for certain types of backhaul. To test this belief, Ericsson evaluated two test cases: reflection and diffraction. In the reflection case, a link with a 100-meter hop length was set up with a reflection in the wall of a building. A stable throughput of 400 Mbps was measured with the 28 GHz system, while the 5.8 GHz system showed a degradation to 70 Mbps due to multipath fading. In the diffraction case, a link was set up with a 150-meter hop length, diffracting the signal on the edge of a building and down to street level. The 28 GHz system had a maxi- mum throughput of 400 Mbps even with a 30 degree diffraction angle, while the 5.8 GHz sys- tem showed more than a 50 percent reduction in throughput in the same diffraction angle. With this study, Ericsson has proven that Wireless Fiber in traditional frequency bands, above 20 GHz, outperforms traditional NLOS solutions. In traditional LOS solutions, high system gain is used to support targeted link distance and mitigate fading caused by rain. For short- distance solutions, this gain may be used to compensate for NLOS propagation losses instead. Sub-6GHz frequency bands are proven for traditional NLOS usage, and using these bands is a viable solution for enterprise backhaul. Contrary to common belief, but in line with theory, Wireless Fiber microwave backhaul in bands above 20GHz will outper- form sub-6GHz systems under most NLOS conditions. The key system parameter enabling the use of high-frequency bands is the much higher antenna gain for the same antenna size. With just a few simple engineering guidelines, it is possible to plan NLOS backhaul deployments that provide high network performance. And so, in the vast amount of dedicated spectrum available above 20GHz, microwave backhaul is not only capable of providing fiber-like multi-gigabit capac- ity, but also supports high per- formance backhaul for enter- prise, even in locations where there is no direct line-of-sight. Real Performance Backhaul is a key element in creating high- performing networks. Limited capacity can result from inadequate backhaul regardless of the investment in the corporate network. Ericsson Wireless Fiber allows you to avoid impact to your user experience with greater spectral efficiencies and capacity. High-performing NLOS solutions enable businesses to optimally deploy their network infrastructure based on what works best in the radio environment. Because of Ericsson's efficient NLOS Wireless Fiber solutions, organizations can achieve 4 to 6 times more capacity in backhaul compared to traditional NLOS solutions. Realize It Wireless Fiber is designed for hops over sev- eral miles, with a superior system gain in a very narrow beam. By using these capabilities in very short hops and by using the environ- ment in a smart way, diffraction and reflec- tion can be used to overcome obstructions between buildings and network infrastructure. The throughput will be very high and stable, ensuring your enterprise stays connected in the most challenging environments. With all of this in place, you can create a network that performs the way your business needs it to-we call it Real Performance . Ericsson's comprehensive, end-to-end microwave-based Wireless Fiber solution is the answer for difficult-to-reach sites for enterprises of all types. Whether it is a perma- nent site, a temporary "pop up" site or an interim site that is waiting on permanent cir- cuits to be installed, microwave-based Ericsson Wireless Fiber can provide high-speed wire- less links up to 1Gbps. Besides extending the network, Wireless Fiber can provide valuable network redundancy and backup. Rethink Non-Line of Sight With Ericsson Wireless Fiber Submitted by Ericsson NLOS Principles As illustrated above, all NLOS propagation scenarios make use of one or more of the following effects: Diffraction All waves change when they en- counter an obstacle. When an electromagnetic wave hits the edge of a building, diffraction occurs - a phenomenon often described as the bending of the signal. In reality, the energy of the wave is scattered in the plan perpendicular to the edge of the building. The energy loss, which can be considerable, is propor- tional to both the sharpness of the bend and the frequency of the wave. Penetration Penetration occurs when radio waves pass through an object that completely or partially blocks line- of-sight. Studies have shown that path loss due to penetration is only slightly dependent on frequency, and that, in fact, it is the type and thickness of the object itself that creates the impact on throughput. For example, thin, non-metallic objects, such as sparse foliage (shown above), add a relatively small path loss, even for high frequencies. Reflection Reflection, and in particular ran- dom multi-path reflection, is a phenomenon that is essential for mobile broadband using wide- beam antennas. Single-path re- flection using narrow-beam an- tennas is, however, more difficult to engineer owing to the need to find an object that can provide the necessary angle of incidence to propagate as desired. For more information, visit www.tessco.com/go/ericsson.

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