MarketElectromagnetic radio frequency convergence
Company Profile

Electromagnetic radio frequency convergence

Electromagnetic radio frequency (RF) convergence is a signal-processing paradigm that is utilized when several RF systems have to share a finite amount of resources among each other. RF convergence indicates the ideal operating point for the entire network of RF systems sharing resources such that the systems can efficiently share resources in a manner that's mutually beneficial. With communications spectral congestion recently becoming an increasingly important issue for the telecommunications sector, researchers have begun studying methods of achieving RF convergence for cooperative spectrum sharing between remote sensing systems and communications systems. Consequentially, RF convergence is commonly referred to as the operating point of a remote sensing and communications network at which spectral resources are jointly shared by all nodes of the network in a mutually beneficial manner. Remote sensing and communications have conflicting requirements and functionality. Furthermore, spectrum sharing approaches between remote sensing and communications have traditionally been to separate or isolate both systems. This results in stove pipe designs that lack back compatibility. Future of hybrid RF systems demand co-existence and cooperation between sensibilities with flexible system design and implementation. Hence, achieving RF convergence can be an incredibly complex and difficult problem to solve. Even for a simple network consisting of one remote sensing and communications system each, there are several independent factors in the time, space, and frequency domains that have to be taken into consideration in order to determine the optimal method to share spectral resources. For a given spectrum-space-time resource manifold, a practical network will incorporate numerous remote sensing modalities and communications systems, making the problem of achieving RF convergence intangible.

Motivation
Spectral congestion is caused by too many RF communications users concurrently accessing the electromagnetic spectrum. This congestion may degrade communications performance and decrease or even restrict access to spectral resources. Spectrum sharing between radar and communications applications was proposed as a way to alleviate the issues caused by spectral congestion. This has led to a greater emphasis being placed by researchers into investigating methods of radar-communications cooperation and co-design. Government agencies such as The Defense Advanced Research Projects Agency (DARPA) and others have begun funding research that investigates methods of coexistence for military radar systems, such that their performance will not be affected when sharing spectrum with communications systems. These agencies are also interested in fundamental research investigating the limits of cooperation between military radar and communications systems that in the long run will lead to better co-design methods that improve performance. However, the problems caused by spectrum sharing do not affect just military systems. There are a wide variety of remote sensing and communications applications that will be adversely affected by sharing spectrum with communications systems such as automotive radars, medical devices, 5G etc. Furthermore, applications like autonomous automobiles and smart home networks can stand to benefit substantially by cooperative remote sensing and communications. Consequently, researchers have started investigating fundamental approaches to joint remote sensing and communications. Remote sensing and communications fundamentally tend to conflict with one another. Remote sensing typically transmits known information into the environment (or channel) and measures a reflected response, which is then used to extract unknown information about the environment. For example, in the case of a radar system, the known information is the transmitted signal and the unknown information is the target channel that is desired to be estimated. On the other hand, a communications system basically sends unknown information into a known environment. Although a communications system does not know what the environment (also called a propagation channel) is beforehand, every system operates under the assumption that it is either previously estimated or its underlying probability distribution is known. Due to both systems' conflicting nature, it is clear that when it comes to designing systems that can jointly sense and communicate, the solution is non-trivial. Due to difficulties in jointly sensing and communicating, both systems are often designed to be isolated in time, space, and/or frequency. Often, the only time legacy systems consider the other user in their mode of operation is through regulations, which are defined by agencies such as the FCC (United States), that constrain the other user's functionality. As spectral congestion continues to force both remote sensing and communications system to share spectral resources, achieving RF convergence is the solution to optimally function in an increasingly crowded wireless spectrum. == Applications of joint sensing-communications systems ==
Applications of joint sensing-communications systems
Several applications can benefit from RF convergence research such as autonomous driving, cloud-based medical devices, light based applications etc. Each application may have different goals, requirements, and regulations which present different challenges to achieving RF convergence. • Commercial Flight Control • Communications & Military Radar • Remote Medical Monitoring and Wearable Medical SensorsHigh Frequency Imaging and CommunicationsLi-Fi and LidarRFID & Asset Tracking • Capable Wireless Sensor Networks == Joint sensing-communications system design and integration ==
Joint sensing-communications system design and integration
Joint sensing-communications systems can be designed based on four different types of system integration. These different levels range from complete isolation, to complete co-design of systems. For example, some recent experimentally demonstrated co-design approaches include: • Tandem hopped radar and communications (THoRaCs), where undistorted orthogonal frequency-division multiplexing (OFDM) sub-carriers are embedded into a frequency modulation (FM) radar waveform • Phase-attached radar/communication (PARC), where FM and continuous phase modulation (CPM) are merged into a single waveform • Far-field radiated emission design (FFRED), where FM multiple-input and multiple-output (MIMO) waveforms produce separate radar and communication beams in different spatial directions == See also ==
tickerdossier.comtickerdossier.substack.com