Motorola

About: Motorola is a company organization based out in Schaumburg, Illinois, United States. It is known for research contribution in the topics: Signal & Communications system. The organization has 27298 authors who have published 38274 publications receiving 968710 citations. The organization is also known as: Motorola, Inc. & Galvin Manufacturing Corporation.

Dual conversion FM receiver using phase locked direct conversion IF

Abstract: A receiver for frequency modulated signals, having down-conversion to a baseband, zero intermediate frequency for selectivity, followed by up-conversion to a non-zero IF for amplification, limiting, and demodulation. A phase-lock loop locks the frequency of the down-conversion source to the center frequency of the signal coupled to the baseband IF, converting the signal to precisely zero frequency. This avoids the beat note often found in direct conversion systems. The phase-lock loop additionally provides inherent demodulation of the FM signal. The received FM signal is coupled to the baseband IF through a radio frequency amplifier for improved sensitivity and local oscillator isolation, or through a first IF comprising a mixer, local oscillator, filter, and amplifier.

Towards Formal Verification of Role-Based Access Control Policies

Abstract: Specifying and managing access control policies is a challenging problem. We propose to develop formal verification techniques for access control policies to improve the current state of the art of policy specification and management. In this paper, we formalize classes of security analysis problems in the context of role-based access control. We show that in general these problems are PSPACE-complete. We also study the factors that contribute to the computational complexity by considering a lattice of various subcases of the problem with different restrictions. We show that several subcases remain PSPACE-complete, several further restricted subcases are NP-complete, and identify two subcases that are solvable in polynomial time. We also discuss our experiences and findings from experimentations that use existing formal method tools, such as model checking and logic programming, for addressing these problems.

Spatial and Temporal Error Concealment Techniques for Video Transmission Over Noisy Channels

Abstract: Two novel error concealment techniques are proposed for video transmission over noisy channels in this work. First, we present a spatial error concealment method to compensate a lost macroblock in intra-coded frames, in which no useful temporal information is available. Based on selective directional interpolation, our method can recover both smooth and edge areas efficiently. Second, we examine a dynamic mode-weighted error concealment method for replenishing missing pixels in a lost macroblock of inter-coded frames. Our method adopts a decoder-based error tracking model and combines several concealment modes adaptively to minimize the mean square error of each pixel. The method is capable of concealing lost packets as well as reducing the error propagation effect. Extensive simulations have been performed to demonstrate the performance of the proposed methods in error-prone environments

Communication system with environmental condition detection capability

Abstract: A communication system (200) includes a portable radio (100) which has environmental detection capabilities. The radio (100) upon detecting the presence of an environmental condition such as smoke above a predetermined threshold, transmits an information signal to a communication station (202). Once the signal is received by communication station (202), it is decoded and a message is annunciated. The communication station (202) can transmit a message to radio (100) in response to the information signal. Optionally, before radio (100) transmits an information signal to the communication station (202), it first determines if the environmental condition (e.g. smoke) has been detected for a predetermined period of time.

Communication management system for personalized mobility management of wireless services and method therefor

Abstract: A communication management system (48) for personalized mobility management of wireless services includes at least one wireless communication device (36), a mobility aware content server (50), and a wireless communication system (10). The mobility aware content server (50) sends a location specific content (60) to the wireless communication system (10) in response to a current location (62), a movement speed (64), and a movement direction (66) of the wireless communication device (36). The wireless communication system (10) is coupled to the mobility aware content server (50), and, upon receipt of the location specific content (60) from the mobility aware content server (50), transmits the location specific content (60) to the wireless communication device (36).