Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

Method and system for encapsulating variable-size packets

Abstract: Encapsulating packets includes receiving packets at a queue of an encapsulator. The following operations are repeated until certain criteria are satisfied. A number of packets are accumulated at the queue. A current encapsulation efficiency associated with the accumulated packets is determined. A next encapsulation efficiency associated with the accumulated packets and a predicted next packet is determined. If the current encapsulation efficiency satisfies an encapsulation efficiency threshold and if the current encapsulation efficiency is greater than the next encapsulation efficiency, the accumulated packets are encapsulated. Otherwise, the packets continue to be accumulated at the queue.

Effect of input harmonic terminations on high efficiency class-B and class-F operation of PHEMT devices

Abstract: Device level harmonic balance simulations are used to show that very high efficiency can be achieved in PHEMT class-B and class-F amplifiers if efforts are made to provide proper input as well as output harmonic terminations. The simulations use a gate capacitance model which accurately describes the C/sub gs/ versus V/sub gs/ dependence for the PHEMT and are illustrated with waveform and dynamic loadline plots which relate directly to the idealized textbook view of high efficiency operation.

RF filtered DC interconnect

Abstract: A filtered button DC interconnect employing a compressible conductor such as a finely wound wire mesh imbedded within a series of dielectric and ferrite cylinders. The compressible conductor is captivated within the series of dielectric and ferrite cylinders to ensure proper contact with mating surfaces of interconnected circuits. The interconnect serves as an RF filter by providing rejection of RF and microwave frequencies between the interconnected circuits.

Centralizer-based survey and navigation device and method

Abstract: A Centralizer based Survey and Navigation (CSN) device designed to provide borehole or passageway position information The CSN device can include one or more displacement sensors, centralizers, an odometry sensor, a borehole initialization system, and navigation algorithm implementing processor(s) Also, methods of using the CSN device for in-hole survey and navigation

Spectrum Bonding and Aggregation with Guard-Band Awareness in Cognitive Radio Networks

Abstract: Spectrum access/sharing algorithms for dynamic spectrum access (DSA) networks are often designed without accounting for adjacent-channel interference. In practice, guard bands are needed to prevent such interference. Introducing guard bands naturally constrains the effective use of the spectrum. In this work, we investigate the problem of assigning channels/powers to opportunistic transmissions, while accounting for such a constraint. Specifically, we propose a novel guard-band-aware channel assignment scheme for DSA systems. Our scheme reduces the number of required guard channels for a given transmission by exploiting the benefit of utilizing adjacent channels and considering already reserved guard channels. We analytically formulate the channel access problem as a joint power control and channel assignment optimization problem, with the objective of minimizing the required spectrum resource for a given CR transmission. We show that the optimization problem is a binary linear program (BLP), which is, in general, NP-hard. Accordingly, we present a near-optimal solution based on sequential fixing, where the binary variables are determined iteratively by solving a sequence of linear programs. Based on the proposed channel assignment algorithm, we develop an operational MAC protocol that enables DSA users to dynamically utilize the spectrum. The proposed protocol realizes our channel assignment algorithm in a distributed manner while relying only on information provided by the two communicating users. Simulation results are provided, which verify the effectiveness of our protocol and demonstrate the significant gain achieved through guard-band-aware channel assignment.