Because LTE has been introduced in a somewhat staggered fashion and the true “4G” as defined by the International Telecommunications Union is yet to come in the form of LTE-Advanced, many wireless operators have failed to notice the limitations inherent in last-generation timing based on TDM lines and GPS satellites. TDM lines can only deliver frequency synchronization while spectrum-efficient Time-Domain (TD)-LTE and LTE-A need frequency and time-of-day synchronization. The difficulty of acquiring GPS signals in urban environments has been obvious for many years. GPS is also susceptible to jamming, with some highly publicized incidents of GPS jamming having occurred recently. Since LTE and LTE-A often are deployed in urban small-cell environments where multiple high-rise buildings prevent line-of-sight fixes on a GPS satellite, it is imperative to find alternative, low cost synchronization solutions for both frequency and time-of-day.