Mobile Data Communications is essential for Emergency Responders and Public Safety Professionals. Choosing the right wireless system has become more complicated because wireless applications in the Public Safety Sector are changing. What used to be the exclusive domain of VHF & UHF is giving way to additional wireless options such as GPS, WiFi and Broadband. Each system has it benefits and understanding these benefits will help the users put together the optimal Mobile Data Communication system. In many cases, the ideal network will actually include multiple wireless systems.
This white paper will point out some of the unique features of each mobile data communications system. Since our expertise is in antennas, this white paper will address some of the factors to consider when choosing an antenna to go along with the mobile data communications system.
New cellular systems are coming online that offer greater bandwidth but require the use of additional frequencies. The established 850 & 1900 MHz cellular bands are being expanded to include the new LTE band at 700 MHz, the AWS & UMTS bands at 1.7 & 2.1 GHz, and the WiMAX bands at 2.5-2.7 GHz.
In selecting a wireless system, it is important to separate the choice of protocol from the choice of frequency. A number of different protocols are already being used on the established Cellular frequencies at 850 & 1900 MHz. For example, the GPRS protocol, sometimes considered 2G, can be an ideal choice for M2M (machine-to-machine) transmission which do not require the latest technologies and fastest speeds. If manageable chunks of data are to be transmitted, this can be a wise choice. But, if larger capacity and higher speeds are needed, a 3G system on the same frequency bands can be selected. The new LTE protocol will initially be introduced on the 700 MHz band but LTE will eventually be available on the other new cellular bands (1.7 & 2.1 GHz as well as 2.5-2.7 GHz).
To keep your options open consider a radio modem, and a broadband antenna, that will cover all of the possible cellular frequencies. For example, Mobile Mark’s RMM-WLF-1C surface mount antenna is broadbanded enough to cover all wireless system frequencies from 694 MHz to 2.7 GHz.
Choose systems that have efficient RF designs with high performance across the entire bands. For mechanical requirements, choose products that are built to be rugged and meet Industry and Military specification for Shock, Vibration, Temperature, and Water Ingress.
Public Safety, 700 MHz
The 700 MHz band will become increasingly important for dedicated public safety use and mobile data communications. Some municipalities have already received waivers to build out networks in the 700 MHz public safety narrowband spectrum. (Mesa, AZ, became the most recent city to receive such a waiver from the FCC on June 14th.)
Earlier in June, the Public Safety Spectrum and Wireless Innovation Act moved out of the Senate Commerce committee and to the full Senate for consideration. This bill would reallocate the 700 MHz D block spectrum (10 megahertz of spectrum) to public safety and give the FCC authority to conduct incentive auctions. As the Public Safety community moves towards nationwide interoperable communications, it is important to have options for both the network backbone and the mobile devices that connect with it. This means specialized 700 MHz site antennas for network development and fill-in, as well as multiband/broadband mobile antennas that combine 700 MHz coverage with other applications such as GPS or WiFi.
UHF & multi-band combinations
UHF has been the backbone of Mobile Data Communications for Emergency Responders and Public Safety professionals. There will still be a role for UHF radios and UHF antennas. But, we will start to see some innovations in this traditional sector. Technology advancements have made it possible to offer UHF antennas that are compact in size and cover multiple frequencies. These new antenna profiles resist damage from impact or tampering as well as accommodate more applications.
We will also start to see more use of multiband applications, for example Mobile Data Communications for Fleet Management often needs to make use of multiple systems. New antenna designs are available, such as the Mobile Mark SMW-310 Series, SMW-310 Series, in which the UHF antenna element can be housed in the same antenna package that covers GPS for Vehicle location and WiFi for mobile hot spots. Or, for undercover applications, antennas such as Mobile Mark’s new License Plate Frame Antenna embeds a UHF and GPS antenna inside a license plate frame for the ultimate in covert coverage.
WiFi Hot Spots & Wireless Video
There are numerous WiFi applications throughout the Public Safety segment that use 2.4 & 5 GHz for mobile data communications, from data links in the police station, to wireless video streaming, to emergency hot spots. A mix of site, mobile and device antennas is generally needed to fill-out a network; mechanical factors such as weather-resistance, compact-size and durability are important.
A recent development is the expanded use of the new 802.11n WiFi protocol which frequently relies on MIMO (Multiple-Input-Multiple-Output) technology. The MIMO system divides the data into more than one unique data stream. Each data stream is modulated and transmitted through a different antenna and transmitted at the same time and in the same frequency as the other transmissions. The MIMO antenna for the 802.11n network would contain three separate antenna elements housed within the same radome. Each element would be fed by a different cable and each would cover the entire 2.4-2.5 & 4.9-6.0 GHz spectrum. For optimum performance, users should install MIMO antennas at both the central transmission/receiving site location and at the individual device.
Mesh Networks, 4.9 GHz
The 4.9 GHz band has been allocated to the Public Safety community for emergency response mesh networking. The FCC allocated 4.94-4.99 GHz which is the largest spectrum allocation for public safety broadband services. Any qualified agency can apply for a license and use the band. The band may be used for terrestrial based radio transmissions; both point-to-point and multi-point operations are permitted. Initial trials are being conducted and many communities are watching to see how this dedicated frequency band will be incorporated into the larger Public Safety wireless space. Some communities are using 4.9 GHz for Downlink Video, Video Surveillance and Backhaul operations. The band is ideal for special event coverage because it can be quickly deployed and offers large bandwidth and strong video capabilities.
This paper started with a simple statement that wireless choices for mobile data communications are becoming more complex. This is a boon for emergency responders and public safety professionals who will be able to combine wireless systems to create customized mobile data communications.