Why Project 25 Phase II TDMA still is relevant

P25 Phase II operation provides public-safety system operators a viable means to add additional voice or data capacity to either fielded systems or new deployments.  Phase II technology also provides flexibility for public safety to partially address spectrum shortfalls.

Additional benefits include the following: 

• P25 Phase II provides an important capability as the public-safety community begins deployment of a nationwide broadband network that currently is not capable of providing mission-critical voice communications.
• The Phase II standards are robust and complete.
• Phase II equipment interoperates with currently fielded Phase I equipment.
• A multi-vendor Phase II product marketplace ensures competition and allows public-safety agencies to procure the products that best meet their operational requirements, while also meeting budgetary constraints.

Looking to the future, because P25 Phase II leverages two-slot TDMA technology in 12.5 kHz channels, it achieves the goal of providing 6.25 kHz equivalent operation—in the process delivering greater spectrum efficiency—while maintaining product costs in line with existing 12.5 kHz offerings.

Jim Holthaus is director of product marketing/development for RELM Wireless.  He has been active in the development of the Project 25 standards and previously served as chair of the TIA vocoder, trunking and conventional-control subcommittees, and currently is chair of the compliance assessment subcommittee.