To: Dr. Sid Davis
From: Zihe Zhao
Subject: Can Wi-Fi Really Be Used to Backhaul Cellular Voice?
Date: February 14th, 2012
As cell phone providers have faced increased demand for bandwidth, customers have faced congestion. Parts of the network where congestion often occurs are; their access control network, the signaling and control portions of their networks, the network packet core, and the backhaul network. Providers have attempted to address this in a couple different ways; by increasing the capacity of network resources and/or, offloading network resources.
A movement to small cells (cellular/Wi-Fi/backhaul) is a major way cellular providers are attempting to deal with increased traffic. Small cells can improve traffic up to 80% during peak usage times and their importance will only increase as providers move to higher capacity 4G/LTE. Indeed, an investment in small cell shipments is estimated to reach $14billion by 2015.
Although microwave point-to-point equipment costs have decreased recently, they usually require a line-of-sight (LOS) link with their connecting backhaul hub. However, when using licensed spectrum, the narrow nature of the bandwidth channels put strict limits on backhaul capacity.
Fiber is another choice available to ease bandwidth constraints. However, it is expensive and will definitely not happen in a widespread manner. It could only be viable in the most dense usage areas.
New backhaul solutions are thus needed for the cellular provider industry. Among new solutions is unlicensed smart Wi-Fi and it appears it will play a large role. In conjunction with more Wi-Fi usage in dense usage areas is the use of fiber. Fiber, however, increases network costs so it is important that cell providers choose carefully where their fiber line leases are in order to maximize the effectiveness of the local increased capacity. This poses a bit of a problem. Given the limits as to where cell providers can place small cells, providers will not be able to use fiber in all locations where usage is heavy. So, an alternative solution is needed.
Microwave radio links can at least partially address this problem as they are great for reliability and because it is licensed spectrum. The cost of installation however is very high so it is good for only very heavy usage areas.
So, Wi-Fi has become an ideal solution for the small cell bandwidth problem. New Wi-Fi technology has been created that combines integrated adaptive directional antennas with smart meshing technology and
