Initial ProSe standards are included in Third Generation Partnership Project (3GPP) LTE Release 13, finalized last March. However, Release 13 ProSe standards are basic and would only alert one device with ProSe that it is within a set distance of another device with ProSe. Without ProSe features targeted more specifically for public safety, agencies cannot fully transition from legacy LMR systems to LTE because direct communications between devices in out-of-network coverage scenarios is an essential requirement for public-safety users.Planning Ensures Smooth Super Bowl Voice, Broadband Communications
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A Motorola Solutions spokesman said that the current ProSe standards in 3GPP are targeted for consumer use cases for device discovery, rather than device communications, and for in-network coverage communications.
LTE Release 14 will define specific frequency bands for ProSe operation, including 700 MHz band 14 for the U.S. First Responder Network Authority (FirstNet) and bands for the U.K. Emergency Services Network (ESN) and South Korea’s planned nationwide public-safety network. 3GPP plans to freeze Release 14 in March, but some public-safety features will be frozen in June.
Emil Olbrich, president of consulting and market research firm PrimeLime, said after the public-safety standards are completed, there has to be a market for the products, and manufacturers have to build products and extensively test them.
Devices are dependent on chipsets that include ProSe. However, prior to investing in ProSe-capable platforms, chipset vendors want high volume commitments from their customer base. Most pre-commercial trial activity during the past three years has been in the commercial domain for proximity-based advertising and social networking for example.
Qualcomm, which developed LTE Direct, the precursor to 3GPP standardized ProSe, did not return a request for comment by press time.
“Harris has considered incorporating ProSe into our public-safety LTE devices, however, the availability of ProSe support in the chipset would dictate when this could happen,” said Michelle Johnson, Harris director of the LTE center of excellence. “We believe the primary hurdle to ProSe-capable devices is chipset availability for public-safety modes of ProSe.
“Introduction of chipsets supporting this significant new capability depends in part on market momentum around its adoption for commercial or public safety. We hope to see the availability improve.”
“Motorola Solutions’ understanding from our industry survey is that there are no publicly available chipsets that have ProSe capability according to the 3GPP standard, and [vendors have] no plan to do so for at least the next two years,” the Motorola spokesman said.
Motorola Solutions’ strategy for direct mode is to use LMR technology for off-network device-to-device communications. The spokesman said the current state of ProSe will not be able to meet public-safety needs for the following reasons:
• Range is limited — LTE off-network coverage range is three to five times less than LMR.
• Latency — LTE has about five times longer access time than LMR.
• Lack of emergency call robustness — Users aren’t able to make a call when LTE channels are busy.
Rugged LTE handset maker Sonim Technologies plans to support both a narrowband LMR type of direct mode as well as ProSe when the silicon software companies and carriers begin to support the feature. Robert Escalle, vice president of public safety for Sonim, said chipset vendors will support this feature as the technology matures and requirements become better defined as to features and functionality of the ProSe element within the 3GPP standards.
Beside the technical limitation in the current ProSe solution for mission-critical public-safety needs, interoperability between devices is critical for 3GPP ProSe to gain adoption within public safety. This process is iterative, as interoperability testing typically results in updates to 3GPP standards, which means ProSe standards will need to be corrected and enhanced. Industry chipsets and solutions will then need to incorporate the updated ProSe standards, the Motorola spokesman said.
Escalle also noted the importance of interoperability testing between different devices to ensure first responders can communicate with each other in a direct-mode implementation. “This will take coordination between chipset and device manufacturers to ensure this happens and is successful,” he said.
Performance testing needs to take place as well, Olbrich said. Band 14 is frequency division duplex (FDD) spectrum with separate transmit and receive bands. A ProSe device operates in time division duplex (TDD) mode in the uplink. This requires a duplexer be placed in the transmit/receive chain of the device, which may increase device cost. Testing and developing nominal performance requirements need to be done before widescale deployment.
“With these challenges both technically and the availability of the LTE eco-system for ProSe, we believe that the ProSe maturation process will take a few more years,” the Motorola spokesman said. “Motorola Solutions is actively participating in the 3GPP ProSe standard to help in the maturation process and will continue to collaborate with leading chipset vendors to mature ProSe technology. Motorola Solutions intends to be the first adopter of ProSe when the technology meets public-safety use cases.”
“I believe ProSe will become available for public-safety users and eventually become an important piece in supporting mission-critical communications for the long term,” Sonim’s Escalle said. “Having a direct mode of communications based on LTE technology is an important aspect of the communications needs of first responders. The ability to communicate from device to device is key to this strategy.”
If government and public-safety agencies commit to investing in ProSe-enabled devices in high volumes, the first commercial shipments of ProSe-enabled devices could be available as early as the first quarter of 2018 following chipset integration, said James Bennett, director of SNS Research.
SNS Research predicts that between 2020 and 2025, ProSe-enabled device shipments in the public-safety and critical-communications sector will increase at a compound annual growth rate of about 53 percent, eventually accounting for a market worth nearly $6 billion by the end of 2025 based on annual unit shipment revenue for ProSe-enabled devices. In 2025, about 8.1 million ProSe-enabled devices will be shipped in the public-safety and critical-communications sector.
PrimeLime’s Olbrich isn’t quite as bullish on the market for public-safety ProSe, saying many pieces need to fall into place before the technology is ready for public safety. However, the vehicle-to-vehicle (V2V) communications market could help ProSe take off because it uses ProSe as well. “If the auto industry or drone industry pushes the necessity for V2V communications, then public safety could use that as catalyst,” he said.
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