Prisons get a new way to stop inmates from using cell phones

It’s hard to keep a bad man down. The Government Accountability Office reported that in 2011 a federal inmate was found running an identity-theft ring from prison using a contraband cell phone. Federal and state prison authorities have confiscated thousands of illegal phones in the past few years, and the Federal Communications Commission and correctional officials say their use poses a public safety risk.


Managing cellular access means really managing it, sometimes daily

A system to block contraband cell phones in prisons must be continually tuned to ensure that it covers the required footprint but does not step out of bounds. Read more.

But keeping them out of prison is a challenge.

“You can try and try and try,” said Sean Smith, head of Mississippi’s Corrections Investigation Division. “But offenders have 24 hours a day, 365 days a year—366 days in a leap year—to figure out how to beat you. It became a security nightmare.”

Phones are smuggled in by staff and visitors and thrown over the fence. “We implemented efforts to stop that, but we couldn’t be 100 percent,” Smith said. “So we thought, if you can’t stop them coming in, how can you prevent their use?”

Jamming the phones is illegal and impractical, Smith said. “I’m inside the unit, and sometimes I need to make a call.” Technology to detect them is not always effective, and once they are identified it can require a confrontation with an inmate to confiscate it.

So in 2010 Mississippi became the first state to implement a managed cellular access system at its state penitentiary at Parchman. “It’s working good,” Smith said. “No technology is 100 percent, but we cut it to an acceptable rate,” and both the number of intercepted transmissions and the number of confiscated phones has dropped inside the walls of Parchman.

Its pioneering use of managed cellular access is only the latest claim to fame for this storied prison. It is located on U.S. Highway 49, just 20 miles from its crossroads with Highway 61 in Clarksdale where blues singer Robert Johnson sold his soul to the devil, according to legend. Since its founding in 1901 it has housed quite a few well-known blues singers (Booker “Bukka” White, John “Big Bad Smitty” Smith), has been the subject of a number of blues songs (“Parchman Farm Blues”), and was the site of many recordings by folklorists John and Alan Lomax now housed in the Library of Congress.

The cellular system Parchman is using is the Intelligent Network Access Controller (iNAC) from Tecore Networks.

“We are a localized cell site for all the networks inside the prison,” said Tecore CTO Casey Joseph. “We become the preferred network for any cellular device,” so that calls from approved phones can be passed on to the commercial carrier, and transmissions from unknown or unapproved phones can be blocked.

The technology still is in the early stages of adoption. A Maryland prison facility in Baltimore that began using iNAC this year is only the second facility using it. But the FCC has proposed new rules that would streamline the subleasing of RF spectrum by commercial carriers to managed access providers, which could speed up adoption of the platform.

Cellular access control is a technology born of necessity. Around 2006, Mississippi correctional authorities found they were fielding more citizen complaints of harassment from prisoners using cell phones. Efforts to block the contraband phones were increased, but were not completely successful. “There was talk of going to the FCC to allow jamming, but that never got off the ground,” said Smith.

The specter of a bill that would allow jamming of cell signals frightened the cellular industry. In 2009 CTIA, the wireless communications industry association, approached Tecore about developing an alternative to jamming, which became iNAC.

The theory of managed cellular access is simple: Install your own cellular base station, much like a femtocell that acts as a low-powered cell for homes and offices, and passes calls along to carriers. Authorized phones are whitelisted on the system and all others are blocked or redirected. Emergency calls to 911 are passed on to a public safety answering point without any approval needed. The challenge is to tune the system so that cell phones within the controlled facility connect to the managed cell rather than to a nearby public cell site, without allowing the signal to leak outside the facility and interfere with legitimate cell phone use.

“We are operating under sub-licensed spectrum with the carriers, so we blend into the network,” Joseph said. Signal strength is only part of the way iNAC becomes the preferred signal. “We don’t have to be the strongest signal, we just have to be configured properly to track the devices.”

The system works with all types of commercial cellular services, including 2G, 3G, 4G/LTE and WiMAX. Getting access to the spectrum requires cooperation with the carriers that own it, which is one of the things that have slowed down adoption of the technology. The first barrier was an 18-month process for the FCC to ensure that there are no legal barriers the technology under current law. The legality has been established, but subleasing the spectrum remains a complex process, although the FCC is working to simplify it.

The commission released a Notice of Proposed Rulemaking in May that would streamline spectrum use agreements between wireless service providers and operators of managed access systems. Agreements for correctional facilities would be quickly processed, with public notice and review periods eliminated or cut short when possible. Another rule also would require commercial carriers to terminate service, if feasible, to a mobile device that has been identified as contraband by a correctional facility.

Fine tuning the RF footprint so that it does not bleed outside the protected facility requires a distributed system of antennas, each configured to position, angle and power level. Some environments are more challenging than others, and the two current installations illustrate the extreme ends of the spectrum. The Baltimore prison is in an urban environment with dense cellular coverage and with public streets and sidewalks, where service cannot be interrupted, running immediately outside the walls. Inside the walls the environment is controlled, so the RF footprint must be finely tuned, with sharp cut-off and no bleed over.

The Parchman facility in Mississippi is rural, sitting on 18,000 acres in the Mississippi Delta in Sunflower County. But careful tuning still is needed in this environment, Smith said.

“Parchman is unique in that we have staff that lives on the ground as well,” he said, and service to personal cell phones should not be disrupted. The facility comprises 53 buildings, farmers lease much of the land and there is a major highway is adjacent to it. “We still have to concentrate and be mindful of RF leakage,” Smith said.

Although not perfect, managed access has been a big help in controlling contraband cell phone use, Smith said. Soon after it was installed, “we had offenders throwing their phones on the floor and saying ‘this thing doesn’t work.’”

About the Author

William Jackson is a Maryland-based freelance writer.


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