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.

Subspace-based blind and semi-blind channel estimation for OFDM systems

Abstract: This paper proposes a new blind channel estimation method for orthogonal frequency division multiplexing (OFDM) systems. The algorithm makes use of the redundancy introduced by the cyclic prefix to identify the channel based on a subspace approach. Thus, the proposed method does not require any modification of the transmitter and applies to most existing OFDM systems. Semi-blind procedures taking advantage of training data are also proposed. These can be training symbols or pilot tones, the latter being used for solving the intrinsic indetermination of blind channel estimation. Identifiability results are provided, showing that in the (theoretical) situation where channel zeros are located on subcarriers, the algorithm does not ensure uniqueness of the channel estimation, unless the full noise subspace is considered. Simulations comparing the proposed method with a decision-directed channel estimator finally illustrates the performance of the proposed algorithm.

MRSVP: a resource reservation protocol for an integrated services network with mobile hosts

Abstract: This paper describes a reservation protocol to provide real-time services to mobile users in an Integrated Services Packet Network. Mobility of hosts has significant impact on the quality of service provided to a real-time application. The currently proposed network system architecture and mechanisms to provide real-time services to fixed hosts are inadequate to accommodate the mobile hosts which can frequently change their point of attachments to the fixed network. Mobile hosts may experience wide variations of quality of service due to mobility. To reduce the impacts of mobility on QoS guarantees, a mobile host needs to make advance resource reservations at multiple locations it may possibly visit during the lifetime of the connection. The currently proposed reservation protocol in the Internet, RSVP, is not adequate to make such reservations for mobile hosts. In this paper, we describe a new reservation protocol, MRSVP, for supporting integrated services in a network with mobile hosts.

Global positioning system communications multi-interface

Abstract: A Global Positioning System (GPS) communications includes a GPS receiver for generating position information, a processor coupled to the GPS receiver by a bus, and a communications multi-interface coupled to both the GPS receiver and to the processor by the bus. The processor presents the position information to the communications multi-interface capable of interfacing with a wide variety of communications systems. Described applications include guided weapons systems, interrogatable tag systems, collision avoidance systems, remote locator/responder systems, beacon location systems, search and rescue transceiver systems, location reporting pager systems, and cellular telephone location systems.

Multi-channel digital transceiver and method

Abstract: A multi-channel digital transceiver (400) receives uplink radio frequency signals and converts these signals to digital intermediate frequency signals. Digital signal processing, including a digital converter module (426), is employed to select digital intermediate frequency signals received at a plurality of antennas (412) and to convert these signals to baseband signals. The baseband signals are processed to recover a communication channel therefrom. Downlink baseband signals are also processed and digital signal processing within the digital converter module (426) up converters and modulates the downlink baseband signals to digital intermediate frequency signals. The digital intermediate frequency signals are converted to analog radio frequency signals, amplified and radiated from transmit antennas (420).

Electronic greeting card store and communication system

Abstract: An electronic greeting card communication system (100) includes a first personal communicator (102), an electronic mail server (136), and a second personal communicator (102). The first personal communicator accepts off-line selection of an electronic greeting card from a user (502), and then transmits a request message corresponding to the off-line selection. The electronic mail server (136) receives the request message and then wireless transmits an electronic greeting card message to the second personal communicator (102) and updates billing information (620) for billing the user of the first personal communicator (102). The second personal communicator (102) selectively receives the wireless transmitted electronic greeting card message and presents it to a user.