Fresh Ideas in Two-Way Communications

TDMA is a widely used and well-known acronym in digital communications, but it can be a foreign concept to those outside the industry. TDMA, which stands for Time Division Multiple Access, is a critical technology in digital two-way radio.

TDMA is most often compared against its counterpart, FDMA, or Frequency Division Multiple Access. Both TDMA and FDMA offer significant benefits over analog technology. TDMA works by preserving the full channel width, but divides it into alternating time slots that can each carry an individual call, thereby increasing call capacity in a channel. FDMA divides spectrum channels by frequency into narrower  channels, each of which can carry a call, which also increases the capacity of the original channel.

So what's the difference to users? Is one approach better than the other?

Both TDMA and FDMA meet the VHF and UHF January 1, 2013 FCC mandate for users to have a spectrum efficiency of one voice talk path per 12.5 kHz of channel bandwidth. TDMA and FDMA can be used in radios that are type approved for 6.25 KHz spectrum efficiency. However, a key benefit of TDMA is that it offers a doubling of capacity in existing 12.5 kHz channels. With FDMA, new licenses for 6.25 kHz in most cases require new licenses and separate channels.

Aside from meeting regulatory requirements, MOTOTRBO™ TDMA radios offer longer battery life and only require one repeater for two talk paths, as well as less ancillary equipment such as combiners. This provides lower costs over alternative radios utilizing FDMA technology for 6.25 KHz spectrum efficiency. TDMA technology also gives users the ability to easily access data applications such as work ticket orders, making operations more manageable and efficient.  It’s critical that radio communications helps workers maintain safety and increase productivity on a day-to-day basis, and for that reason Motorola Solutions has chosen TDMA technology for the MOTOTRBO digital two-way radio portfolio.

To read more about how TDMA technology can increase digital radio capacity and functionality, please click here. For more information on the MOTOTRBO Professional Digital Two-way Radio System, visit www.motorolasolutions.com/mototrbo.

Tom Mockridge is the DMR Industry Relations Director for Motorola Solutions Inc., and the chairman of the Tech Working Group with the DMR Association.

If you are attending the 2012 International Wireless Communications Expo, please stop by "Comparing Digital Technologies: Choose Your Next Generation Communications," on Friday, Feb. 24, from 10 a.m. - 12 p.m. PST, where I will be speaking on the panel.

Source: Motorola Solutions