07.06.2010 by Andrew M. Seybold
This type of voice communications is not now available using cellular and wireless broadband networks, nor will it be well into the future. The devices we use to communicate over commercial voice and broadband networks are 100% reliant on being within range of a cell site.
Part 1 of 3
One of the most misunderstood aspects of public safety communications is the need for peer-to-multi-peer communications when at an incident. (In Land Mobile Radio speak, this is called simplex, tactical, or talk-around communications.) It is important that those making policy in Washington, DC, those on the commercial side of wireless, and IT professionals understand exactly what this type of voice communications entails and the critical role it plays in public safety communications.
Consider this scenario: You are in a large shopping mall with your family and you each go in different directions, agreeing to meet later at the food court. You are in a store and you find a bargain that you want your spouse to see before you buy the item. You pull out your cell phone only to find that you do not have cell phone coverage in the mall, so you can’t call your spouse’s cell phone to ask him or her to meet you at the store. Your son or daughter is walking in the mall and sees someone fall down the stairs. He or she reaches for his or her cell phone to call 911, and again, finds there is no cell phone coverage, so the call cannot be made.
The problem in both cases is that you are out of cell site coverage, and without a cell site, your phone does not work. It is simply a great piece of technology that is useless when you are not in range of at least one cell site. To you this is an inconvenience, but for the person who fell down the stairs and is injured, the delay in getting assistance could be the difference between living and dying. This is not acceptable in the world of public safety communications where those on a scene need to be able to communicate, especially with each other, no matter where they are and regardless of the conditions.
There is a type of voice communications that enables public safety personnel to communicate among themselves even when they are out of range of a cell site or a tower site, and it is vital to the way in which public safety personnel on the scene of an incident operate. Using the same mall as an example, once the fire department and EMS personnel arrive, they switch their radios off of the dispatch channel to a channel that provides the ability for them to talk to each other over short distances. These voice transmissions are heard by all personnel at the incident. (To be clear, fire and EMS personnel can talk to each other, and the police, usually on another one or more channels, can talk to each other.)
This capability provides good communications between those on the scene, and if they need to contact their dispatcher they can contact someone in their vehicle outside the mall, who in turn can relay the request for additional assistance to the dispatcher. Further, if a fire fighter is on the second floor of a burning building and sees that the roof is about to collapse, he or she can make a call that will be heard by all personnel in the building, alerting them to the danger. And if the person making the call is in danger, they can provide assistance. Again, this type of communications is vital to public safety and it is used every day at many different times.
Yet this type of voice communications is not now available using cellular and wireless broadband networks, nor will it be well into the future. The devices we use to communicate over commercial voice and broadband networks are 100% reliant on being within range of a cell site. If two people are separated by only a few blocks, they still must dial a phone number and wait for an answer, which means they both must be in range of a cell site to be able talk to each other. First responders simply change the channel their radios are set to and instead of talking over the network, they talk directly to other units within range.
Those familiar with Citizen Band radios, or walkie-talkies that use the Family Radio channels authorized by the FCC, know how this type of communications works. It is based on push-to-talk, and units can talk among themselves without going through any relay towers or cell sites. This type of service is not available in the world of commercial wireless. While some people seem to think it will be available in the future, I don’t believe any wireless broadband equipment or device vendors will be building in this type of communications capability.
There are many different reasons that this type of communications is not and will not be available: There are technology challenges, network operators want their customers to make use of their networks to provide income, and there is no demand for these types of services from the general population. But those who claim public safety’s needs can be completely served by commercial-type broadband networks apparently do not understand the need for direct communications. Again, this is not a “nice to have” feature for public safety, it is a must-have requirement. Unlike the annoyance of not being able to make a phone call when you are out of cellular coverage, the inability to talk to others at the same incident can be deadly. It could result in the loss of life not only within the first responder community, but also for others involved in the incident.
I have heard several comments from those who believe broadband networks can provide all of the capabilities needed by public safety that further indicate how much this direct voice requirement is misunderstood. The first set of comments has to do with being in coverage—broadband believers suggest that there will be coverage everywhere, and where there is no coverage from a cell site, in-building communications systems will provide communications capabilities. This simply is not true. No matter how robust a network is, no matter how many cell sites it contains, there will be places where there is no coverage. Further, even if there is coverage, it does not make sense for ten, twenty, or more first responders on a scene to tie up wide-area communications channels when local-area communications will serve their needs, and serve them better.
Add to this the fact that at larger incidents that occur on a daily or weekly basis, there is also a need for multiple local channels. This is because there are a number of different groups at these incidents, all with their own set of objectives and tasks. While public safety personnel need to be able to talk within their own group, they cannot have to compete with other groups for a radio channel. A simple example of this might be a bank robbery gone bad that has turned into a hostage situation. On the scene there will be patrol officers who first responded to the incident, a swat team, a surveillance team, detectives, fire, and EMS responders. At this type of incident, each group needs at least one channel dedicated to its own team to coordinate among themselves. At the command post, the incident commander is able to follow what is going on within each team, which enables him or her to make informed decisions about how to handle the incident. The incident commander must also have a clear channel back to the dispatch center and/or superiors who are monitoring the event from remote locations.
During storms, wildland fires, and many other situations, the number of local channels that are needed must be available; having only one such channel is not acceptable. During the recent Southern California wildfires, between local, state, and federal fire agencies, there were 18 command channels (wide-area coverage) and 78 local-area or simplex channels in use. By the way, much of the area engulfed in flames was outside commercial network coverage and some was even outside areas covered by the existing public safety networks. However, because there were local communications capabilities, incident command was able to track everyone on the fire lines and if someone got into trouble, he or she knew that by pushing one switch on the radio and saying, “I need help” or “I’m in trouble,” he or she would be heard by nearby team members.
Public safety needs broadband services, but today, voice is the primary form of communications in the field. Data services will help augment the tools available in the field and will help reduce some of the voice traffic on public safety systems. Data services will also provide a common network for broadband services as well as the ability to use the broadband spectrum for push-to-talk voice services for interagency communications at some point in the future. However, the broadband network will not be capable of handling the requirements for channelized voice services, nor will any of the commercial broadband technologies be capable of providing the type of direct voice services described above.
Those who are in the process of reviewing the requirements of public safety communications need to understand that its voice requirements are very different from those that are and will be provided over commercial technology broadband networks. They also need to realize that public safety needs three types of communications: wide-area (city or region-wide) voice for dispatch and coordination, local voice communications for use during incidents, broadband services for data and video communications, and in the future, some voice for coordination and administrative purposes. Armed with this knowledge, they will understand why the planned nationwide broadband network can only augment the capabilities in the field — not replace them.
Andrew M. Seybold