it is not that expensive, China in fact is doing it.

The first ground station is operational now for testing purpose. The system is called ADS-B which replaces the current ARINC's ACARS. If I remember correctly ACARS covers most of the Chinese air space. ADS-B allows the terminal inside the aircraft to transmit the aircraft position obtained from GNSS (GPS, or other similar systems) to ground station. ADS-B used GlobalStar LEO sat which covers most of areas for communication rather then ACARS using GEO station sat. That means it is gonna be faster and safer. South Korean company helped Chengdu to set up ADS-B ground station. By 2020, Most of Europe and North America will transition to ADS-B. I don't know exactly what the deployment schedule for China is.