MIMO and Smart Antennas for Mobile Broadband ... - 4G Americas

6.6.5 ADVANTAGES OF REMOTE FIBER FEEDERSThere are a number of advantages in using the combined fiber/copper remote fiber feeders, comparedwith the separate fiber and copper cables used up to now.• Lower total material and installation costs. No conduit required.• Ease of handling. One cable per sector. Ease of routing.• Environmentally and mechanically protected.• Reduced tower loading.• Reduced tower real estate cost.• Standard coaxial accessories.6.7 CO-SITING OF MULTIPLE BASE STATIONS AND TECHNOLOGIES6.7.1 SEPARATE FEEDERS FOR EACH SYSTEMIn an ideal world, each base station and air interface technology deployed on a cell site would have itsown feeders and antennas. This would have several benefits:• Individual optimization of antenna pattern, azimuth direction, and down tilt for each service.• Minimum RF path loss and mismatch.• Reduced concerns for interference and intermodulation between systems.• Maintenance work on one system need not impact other services.However, a number of constraints influence the site architecture and reduce the system designer’soptions. In most situations, factors that must be considered include:• Zoning restrictions on the quantity and design of antennas and other equipment.• Limits on weight and wind loading of feeders and tower mounted equipment.• Cost savings opportunities on capital expenditures, lease costs, and installation labor.• Time to market requirements for rollout of new services.A variety of co-siting solutions have been developed to address these constraints while enabling efficientoperation of multiple technologies in a shared architecture. Today, these solutions are widely used withinmajor carriers’ networks and competing operators have also joined together to reap the benefits ofsharing site equipment.4G Americas MIMO and Smart Antennas for Mobile Systems – October 2012 – All Rights Reserved103