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Chicomm Blog

Converge, Integrate, Understand: LMR vs. LTE

Posted by Jill McNamara on Friday, November 2, 2012

      One major point to keep in mind before we dive into LTE (Long Term Evolution) & LMR (Land Mobile Radio) is that it will be many years, maybe even a decade before the transition is made and convergence plans are rolled out completely. There are understandably many concerns about the latest technologies being introduced, ranging from costs to planning to integration—and there is not a simple answer to these concerns. The convergence options made possible will have a lot of different benefits for a lot of different users that will depend on the users in each community. Therefore every agency will have its own set of possible solutions. One thing we can all agree on though is the rise of expectations for first responders and the increasing demand for the tools that make it easier for public safety personnel to do their jobs. Now let's take a step back and break down the complex capabilities of both LTE & LMR.ALPR LTE LMR

Some facts about LTE & LMR:

  • LTE was selected because it’s the same technology being rolled out by commercial operators.
  • LMR is designed for narrowband critical voice while LTE is designed for broadband data and video
  • LTE is cellular based, uses mostly low level sites & reuses same spectrum for each sector and each cell site (a challenging design ensured by engineers to prevent interference)
  • LTE uses 3 outbound and 2 inbound rates; the closer you are to a cell center the higher the data rate will be
  • LTE is designed for multiple antenna use (a technology called MIMO)
  • System design Is very different. LMR are high level sites, LTE is low-level;

 There are more differences between the two to be aware of such as the power requirements & coverage for each. LMR transmits as needed while LTE is running 24/7/365--meaning the electrical charges will be much higher. And the coverage distance is much less for LTE (1-3 miles) than LMR (20-40 miles)

    For example, in Santa Barbara: LTE is at 700 mHz using 62 sites; Verizon has 78; AT&T has 81; providing coverage in 93% of the county. In door coverage will be fair but not good, and the version released first for public safety will not have 1-to-many communications.  Depending on terrain and other conditions a roughly 10 mile radius of coverage in a rural community would be expected. 

     Now, LTE will provide value. For LTE, access is associated with the data at the level specific to how it meets operational needs. Just like with smartphones, there is an expected boom of developed applications & services expected to simplify processes they have right now and improve capabilities in the field. Beyond the day-to-day tools, applications will add capabilities such as streaming of video to a small screen for facial recognition. 

   But as mentioned, there are questions and concerns that must be addressed.  LMR voice has been the way public safety has been communicating forever. So how will LTE be able to handle voice and data? A broadband network at 700MHz will not be able to replace LMR in many locations across the US due to RF properties. LTE may be just a layer and not necessarily a complete migration for LMR. Matching LTE to LMR coverage and reliability is cost prohibitive. Plus it will definitely be crucial to manage your bandwidth very effectively. It is not a good use of the network to backhaul your data because doing that will be taking a slice of the capabilities away from other users.

     There are other questions to consider such as: Why would a community build a 2nd network when the community already has LTE? One of the fundamental reasons is although commercial LTE works, it is not built to mission critical standards. And when there is an incident, citizens and reporters get on the network and there is no bandwith left for public safety. There hasn't been a way to give preemptive priority to public safety before so a network for public safety only is completely necessary.

Still others may wonder, when would it make sense to replace a LMR with an LTE, especially if you just updated your LMR for narrowbanding? Nobody knows for sure…but you shouldn’t make any move until a mission critical voice for LTE has been up and running for a year or so…which isn’t predicted until 2018-2020. It also depends on your location if you will ever be able to completely replace your LMR. What we know is there is still a lot more left to figure out. Not every question can be answered yet. Some parts of planning are too far off to consider right now…but it is important to understand the need to continually improve public safety performance in order for communities to thrive. 

Public Safety Communication Checklist

 

Jill M

This article was written by Jill McNamara, Internet Marketing Coordinator at Chicago Communications, in response to an Urgent Communications webinar panel discussion covering Planning for the Future with LMR & LTE. Jill has written all of the Meet Our Techs & Employee Spotlight articles for ChiComm's blog and continues to seek opportunities for articles relating to the wireless communications industry. If you'd like to submit a suggestion for JillContact Us!

An Executive summary of the Urgent Communications "LTE & LMR: Planning for the Future" presentation can be found here:  http://images.go.pentonmarketingservices.com/Web/PentonMMS/%7B200a1dd3-687e-4ce3-8615-3d737512921a%7D_Anritsu_ExecSummary_LTEandLMR.pdf

 For additional information on Land Mobile Radio testing for P25+LTE, visit Anritsu at www.anritsu.com.