Decision Making under Uncertainty for Dynamic Spectrum Access

ABSTRACT: Due to scarcity of spectrum, Dynamic Spectrum Access (DSA) becomes a needed technology to improve the utilization of electromagnetic spectrum for DoD satellite communication. However, current DSA approaches are developed for terrestrial communications without addressing the unique challenges for SATCOM environments such as error-prone spectrum sensing, high mobility, and large coverage. In this project, InfoBeyond advocates novel Efficient and Robust Dynamic Spectrum Access under Uncertainty (ERDSAU) algorithms. ERDSAU models the DSA in the SATCOM environment as a problem of Partially Observable Markov Decision Process (POMDP). Partial observation indicates that a LEO satellite is only able to sense a partial of spectrum channel. Under partial observation and imperfection awareness of channel, POMDP is an optimization problem that allows a LEO satellite to optimally take action on the spectrum channel. In a collaborative way, ERDSAU tracks each spectrum channel by a probability distribution over the set of possible states that is evaluated on a set of observations and observation probabilities and the underlying Markov decision process, providing high accuracy on decision making. Furthermore, ERDSAU prioritizes the LEO satellites in detecting spectrum holes to improve the resource allocation between multiple satellites. ERDSAU also provides computationally efficiency in response to change of spectrum status. BENEFIT: The ability to provide spectrum sensing and decision making under uncertainty environments increases the spectrum utilization and is proving useful for DoD SATCOM communication. However, the current approaches are very limited to offer such capability for SATCOM environment where sensing is error prone and satellites moves fast. Our proposed ERDSAU provides an innovative approach that provides the capability of spectrum sensing and access decision making under high uncertainty. ERDSAU represents a vital advance on the frontline of the cognitive SATCOM environments. Once it is developed as COTS/GOTS products, ERDSAU leads to several key business benefits. At first, ERDSAU can be deployed in the military SATCOM environments. The unique issues of Low Earth Orbit (LEO) Satellites spectrum sensing are addressed such that the secondary users can optimally access the spectrum holes of the primary users without affecting to theirs normal transmission. The proposed ERDSAU utilizes the unused spectrum period of the primary users that significantly increase the system performance. These features are highly desirable in many military scenarios where the large volume of data needs to be delivered constrained on the frequency spectrum. Secondly, it can be used for disaster response SATCOM environment. In the case of disaster, SATCOM is indispensable on communication network around the disaster area such that personnel can rapidly response to rescue and first response services. It can also be used for national communications and other environments. ERDSAU offers the capabilities of delivering critical information in the case of the main communication links are downed or attacked. Air Force would gain significant value from the commercialized dual-use ERDSAU products. ERDSAU can be used in many tactical applications in the SATCOM military and governmental networks. ERDSAU can also be applied for business and commercial networks to improve the utilization of the frequency spectrum. The private market size is much larger than that of military applications where the individuals or organizations can efficiently utilize the unused spectrum holes to increase the data transmission rate without increasing the expense. Our efforts for the DoD and commercial markets are to transition the ERDSAU technology into various applications and attract a great amount of investments by successfully creating new markets. We will closely work with our partners to transfer this technology into military and commercial domains.