About those old radios.....

In November of 2019, the State of Arkansas entered into a contract with Motorola to upgrade the AWIN system to APCO P25 Phase 2. Phase 2 makes more efficient use of the spectrum by using a 2-slot, time-division multiple access (TDMA), which provides additional operating capacity. The upgrade is anticipated to be completed in 2023.


As the upgrade rolls out across the state, the question most often asked of AWIN is, "How long can I keep my old FDMA radio?" In an effort to keep our Users informed, AWIN will continue to share what we know.


CURRENT STATUS OF FDMA RADIOS ON AWIN


  • At this time, AWIN (State of Arkansas) does not have a directive to remove FDMA/Phase 1 radios from the AWIN system.


  • AWIN and ADEM are acutely aware of the impact such a directive would have on AWIN Users and places the highest priority on User safety and interoperability.


  • In the future, if AWIN is given a directive to set a final phase-out date for FDMA radios, it will be planned ahead with ample lead time for User Agencies to work with their normal budget cycles to accommodate equipment replacement.


  • FDMA radios now active on AWIN may remain on the system in their current capacity.  Once an FDMA radio is inhibited or removed, it may not be reactivated nor transferred (gifted) to another agency.


  • New AWIN radio IDs are only issued for P25 Phase 2/TDMA radios.


FDMA vs. TDMA: WHAT IS THE DIFFERENCE? 


On a frequency division multiple access (FDMA) system, each frequency (channel) can support only a single conversation and user at a time. Time division multiple access (TDMA) allows a channel to support two conversations at a time by alternating between the first and the second in a fraction of a second. This happens so quickly and seamlessly that it is unnoticeable to the user, who experiences what feels like a solid, unbroken transmission. The result is a doubling of the system's capacity to handle radio traffic.


P25 Phase 2 (TDMA) is backwards-compatible with Phase 1 (FDMA) products, so the older model radios currently on AWIN will continue to work. In an area upgraded to TDMA where Phase 1 (FDMA) subscribers are also present on the system, the channel will default to the Phase 1 mode to maintain compatibility with these users, but this will decrease the operating efficiency of the system.


THE AWIN UPGRADE TO TDMA


All AWIN sites have been upgraded to TDMA as part of a larger statewide system upgrade, which will be completed in 2023.


At this time, there is no plan to require AWIN users to replace their Phase 1 radios by a specific date; however, the sooner they are tapered off the system, the sooner all AWIN users will benefit from the doubled capacity of TDMA. To this end, AWIN stopped issuing new radio IDs to Phase 1 (FDMA) radios in December, 2019. As agencies replace radios, the replacements must be Phase 2 (TDMA) devices.


Be aware that new radios advertised as “Phase 2-capable” may require additional firmware and programming to enable them to function as TDMA radios and must have this capability enabled to be allowed on the AWIN system.


QUESTIONS?  CONTACT US!


Penny Rubow, AWIN Director

501-682-5358 or penny.rubow@adem.arkansas.gov


Rachel Wilson, AWIN User Experience Lead

501-683-0491, or rachel.wilson@adem.arkansas.gov