Demand for “everywhere” mobility is, well, everywhere these days. This is placing carriers and mobile network operators under increasing pressure to relieve networks that are becoming overburdened with the demands being placed on them by users.Despite migrations to 3G, 4G LTE and WiMAX, the proliferation of cellular devices and apps requires network operators to take additional steps to increase capacity and coverage. As a result, virtually all network operators are employing small cells to increase capacity in urban areas and provide coverage where gaps exist.
Most carriers are focused on deployment plans in which the majority of small cells will be backhauled using existing fiber or copper. While physical connectivity can work in the majority of cases, total coverage requires backhaul that connects where fiber and copper can’t. In addition, fiber can be cost prohibitive, particularly for spanning long distances, and when time to deployment is a factor.
In such cases, wireless technology can provide the ability to rapidly deploy reliable small-cell backhaul solutions. However, carriers need to select a small-cell backhaul system that will deliver carrier-grade connectivity and overcome physical obstacles and interference.
What to Look for in Wireless Small-Call Backhaul
While small cells are becoming an answer to a range of capacity and coverage issues, significant challenges still remain in deploying them. Backhaul can be one of the greatest challenges network operators face. As such, there is no single solution or “cure all” that can handle every situation carriers face. Because small cells are typically deployed in a wide variety of both indoor and outdoor, urban and rural, environments, carriers need to look to backhaul solutions that can overcome a variety of deployment problems.
Realizing the full benefits of small cells depends on the ability to configure and deploy the right system for each small cell network. Differences in site location, distances to the Point of Presence (PoP) and the macro network, the number of small cells in the network, environmental path conditions, interference potential, and applications are just a few examples of the many variables that can present challenges for backhaul networks.
To deploy a network that will provide the flexibility and effectiveness needed to give your network the backhaul boost it needs, look to include the following:
Multiple-Input Multiple-Output (MIMO) – MIMO provides consistently reliable, high-performance communications even in tough environments, significantly protects against fading and increases the probability of making a successful connection.
Orthogonal Frequency Division Multiplexing (OFDM) – OFDM is necessary to help overcome interference and near line of sight (NLOS) issues. Some wireless backhaul providers are now offering intelligent solutions embedded in their OFDM products. This can help resolve channel dispersion, achieve higher spectral efficiency, and provide high resistance to frequency selective fading. In addition, it provides significantly more pilot tones and sub-carriers as well as instant fade recovery.
Spectrum Management Optimization – When channel frequencies can be set dynamically (either manually or dynamically), radios can sample the band hundreds of times a second, automatically switching to the clearest channel. This provides similar spectrum-optimization benefits as having exclusive rights to a licensed channel.
Adaptive Modulation – Look for a solution that provides transmitters and receivers that can negotiate the highest mutually sustainable data rate and dynamically “upshift” or “downshift” the rate as path conditions change so that you can get the maximum performance possible within current power limits.
GPS Synchronization – With GPS synchronization, multiple radios can be deployed on a tower or rooftop with greatly reduced interference.
Time Division Duplex (TDD) Synchronization – TDD Synchronization allows carriers to time and synchronize their transmit and receive signals for more efficient frequency reuse. Consider solutions that also offer wayside T1/E1 integration within the TDD structure for lower jitter and wandering. Then you can co-locate multiple radios on a rooftop or tower with minimal interference.
Spatial Diversity – Spatial diversity is good for combating ducting and multipath fading. It also allows your communications to travel over water, across vast expanses of open terrain and in deep non-line-of-sight environments without signal loss.
Using a small-cell strategy can help carriers meet the increased demand for everywhere access. By thinking ahead and employing a strong backhaul system, carriers can both maximize and expand their networks and customer offerings.
About the Author
Hunter Pinnel is in Global VP/Wireless Carrier Sales at Cambium Networks.
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