ProSe off network capabilities were developed to replace and enhance the capabilities of Land Mobile Radio (LMR) Talkaround. Current ProSe standards fail to match the range capabilities of LMR direct communications. Vehicle to Everything (V2X) standards that have further developed direct communication capabilities generally have use cases were message priority lessens with distance. Braking due to road hazards would be an obvious example. By contrast isolated worker scenarios have priorities that depend on the nature of the communications rather than distance. New work in direct communications may be taken up in 5G. This work should include the capability to extend coverage when relays and networks are not available. - July 2019
Daniel W. Ericson, serves as Principal Investigator and the Program Manager for PSIAP. He is a Senior Scientist with extensive experience in multi-disciplinary complex system definition, product strategy, development, management, and qualification.
Dr. Dennis Martinez
Dr. Dennis Martinez is the Chief Technology Officer for Harris Public Safety division and the Executive Sponsor for the PSIAP grant.
Ms. Altieri is the Grant and Funding program Manager for HarrisCorporation Public Safety group and the Administrative Officer for the PSIAP grant
Direct communications that allow user devices to communicate without an intervening network, have been well accepted as a cardinal requirement for mission critical communications, particularly to support tactical operational scenarios. A part of addressing this public safety requisite in next generation cellular systems, is 3GPP defined ProSe (Proximity Services.) This service includes off-network modes that were developed to address the direct communication needs of public safety users. However, these modes have not been evaluated in realistic situations to understand whether ProSe meets current public safety methods of operation, use scenarios, ease of operation, or if it will meet expectations to provide high-speed data services like video.
ProSe is shown to have a coverage range that is about one third of P25 technology, its predecessor for public safety direct mode operation (DMO) communications. In realistic scenarios where the Long-Term Evolution (LTE) band is loaded with network traffic or other ProSe communications, system self-noise may further limit range. A primary concern is that ProSe may not be accepted by public safety users if it has a substantially shorter range. Even the current range of P25 DMO can be problematic, particularly in rural settings like wild fire fighting. Providing mechanisms to extend ProSe range over its predicted level are essential. Uncertainty about whether ProSe can provide a reliable service is also of major concern. LTE eNB network interference management methods are well established. In contrast, ProSe as an ad hoc network has distributed control, and consequently coordination is more difficult. First responders expect a service that is predictable and available. Consequently, the ProSe service must find ways to provide a highly reliable service in the face of self-interference issues. Harris proposes to develop solutions that both extend range and the reliability of ProSe.
In addition to range issues, the current standards do not address the management of DMO that may operate completely independently of a LTE network or may interact with a network. Simplicity of operation for both the user of DMO services and the administrator of these services is critical. Ideally, the user may only be peripherally aware of DMO. Network management functions for allocating resources, dynamic routing, relays and generally separating the user from the details of the network will be provided.
New work in the 3GPP standards including V2X and Internet of Things (IoT) include new capabilities that can be considered for improving some of the shortcomings of ProSe range. These standards have largely evolved on parallel paths and have not shared common requirements or solutions. Harris proposes to identify applicable standard based techniques and incorporate them as part of a ProSe solution that meets the expectations of public safety users. Harris is confident that it can develop a DMO solution that meets user expectations, provides seamless network transitions, and is easy to use.