One of the other main features of the OpenSky is its ability to compress more users and information on to less spectrum. By utilizing four-slot Time Division Multiple Access (TDMA), multiple transmissions are allocated on a single RF channel to double or quadruple network voice capacity (6.25 kHz equivalence on 25 kHz bandwidth). Plus, employing the IP-based network architecture of the VIDA network, end-to-end Voice over IP (VoIP) provides security and unprecedented access.
OpenSky also provides in-band network extension to portable radios that cannot directly connect to the network. Additionally, optional GPS technology for AVL exists, decreasing radio traffic to and from dispatch while the network automatically logs call times.
Over-the-Air Programming (OTAP) means that mobile radios mounted in vehicles and portable radios at the station stay in service. Data packets are transmitted to the device incrementally, only during times when the device is not in use. Once all the packets are received, the device automatically and quickly reboots, providing the user with the latest software package. Over-the-Air Rekeying (OTAR) of security encryption keys also saves time, costs and the need for spare radios.
“From a networking standpoint, we’re able to give voice communications priority over data,” Logan said. “You don’t want to ever have a busy signal. These packets can be prioritized. Because of that ability, there doesn’t really appear to be having any drawbacks to having voice and data integrated.”
Each OpenSky subscriber is assigned a unique user ID, similar to a computer network log-in. User IDs and passwords are pre-configured in the radio or entered through the keypad by the user. The IDs are used to validate users on each device, assign personalities and corresponding privileges, and identify users when communicating. Each unique ID can be used to log in to multiple devices at once. For example, an officer can log in to a mobile radio in the patrol car as well as a portable radio when leaving the vehicle. Because the personalities are managed at the network level, each device that logs in will be sent the same personality and privileges through over-the-air provisioning, which makes switching between the two devices easier for the user.
Furthermore, supervisors or dispatchers can override a transmission in the case of a stuck microphone or to initiate an emergency call. This llevel of Tranmit Control is selected by the system administrator at the network management level.
Overall, Brennan said Pennsylvania is thrilled with the flexibility and capabilities of the OpenSky system. If there is one complaint that Brennan and the Commonwealth of Pennsylvania Office of Administration hear about is coverage of the 800 MHz frequency band. Using that frequency was required in the original contract, but he said using the VHF frequency range would have allowed more coverage.
The good news is that the architecture of OpenSky is far different than conventional radios, so for minimal environmental impact, the OpenSky Cell Site can incrementally extend coverage into otherwise hard-to-reach areas. So to solve coverage problems, you don’t have to build a tower, which costs around $250,000, according to Brennan. Instead, OpenSky lets you put up cell sites, which are basically 90-foot telephone poles. To put up that pole solves the coverage problem and costs around $80,000.
“The flexibility of the architecture has again been so fantastic for Pennsylvania,” Brennan said. “We’re operating in some places where there is no cell service. They couldn’t even buy this service in many parts of the state. They are running data right through the radio network.”
With its low power consumption, a 24-hour battery backup and easy serviceability, the OpenSky Cell Site is a powerful alternative where in-building or rural coverage is necessary.
One of the features of PA-STARNet that has been unpopular with members of the media in Pennsylvania is that there is no commercial scanner that can pick up OpenSky, Brennan said. Officials are so confident that no one, including the press, can hear them that they don’t even encrypt the transmissions, he said.
“The security as far as outsiders getting in is outstanding,” Brennan said. “The system demonstrates incredible flexibility by allowing you to be private when you want to be private and allow you to be sharing when you want to be sharing.”
All radios are password protected to prevent unauthorized use. If a radio is stolen while a user is already logged in, remote activation/ deactivation is available at the network level. System security is further enhanced by a wide range of “Information Assurance” services and options focusing on commercial off-the-shelf (COTS) IP-based products.
Interoperability in Action
During the G-20 Summit in Pittsburgh in 2009, the OpenSky system was used to connect all manner of first responders, state agencies and other partners to maintain a safe and secure environment. Brennan said it was the most interoperable setup that he has ever seen.
Everybody was connected through voice, data and video. Live video was streaming from helicopters to the command post, and the Department of Health was able to monitor what was going on at the scene, as well as hospitals and other emergency personnel.
The system has performed well during statewide emergencies and major events like the G-20 Summit, Brennan said. But he emphasized that interoperability is happening on a daily basis between officers and dispatch centers across the state. This is especially helpful in some of the more rural areas of Pennsylvania, he said, where state police often get the help they need from county officers who may be closer for back-up than the next state officer and vice-versa. “The most important thing that I think we have done is that we started to tie in the counties,” Brennan said.
The Future of OpenSky
So far, Brennan said 67 counties in Pennsylvania and 69 9-1-1 centers are connected to the state system along with the State Police and many other state agencies. Logan said rural county public safety agencies and quasi-public safety agencies that don’t have funds to set up their own communication systems would be excellent candidates to leverage the infrastructure already set up in Pennsylvania. In some cases, there is a cost to transition if the entity needs additional or special capabilities. But in many cases, all they need to do to hook up to the system is purchase the mobile radios for their users, he said.
“The beauty of having the network here in Pennsylvania is that it’s very robust and has the capacity to accept many, many, many more users,” Logan said. “There’s a lot of available capacity on this system.”
As more agencies in Pennsylvania are seeing their legacy systems’ lifecycles running out, they are joining up with the statewide network, which will only keep improving over time with advances in hardware, routers and speed of computers. “All those things enhance the network,” Logan said.
The future looks bright for the Commonwealth of Pennsylvania and its PA-STARNet system. In addition to the Commonwealth of Pennsylvania, OpenSky has been installed and is in use by police, fire, transit, transportation and utilities agencies across the country. As a large-scale system, Pennsylvania provides a good model for any state, county or group of counties that are interested in their own wide-area deployment.
Candy Phelps is a frequent contributor to Public Safety IT. She can be reached at candybuster1@ yahoo.com. Photos courtesy of Harris.