Abstract:
Characteristics of the radio channel are used to establish pseudorandom sequences for use in communicating information. These characteristics are the short-term reciprocity and rapid spatial decorrelation of phase of the radio channel. Due to the reciprocal nature of these radio channel characteristics, the transceivers which are communicating via the radio channel will generally both determine the same sequence. Although the determined sequences are not always sufficiently random for use in pseudorandom functions, a randomness tester can be provided to discard those sequences which are not sufficiently random. Exemplary pseudorandom communication functions include the selection of a spreading sequence in CDMA systems and the selection of a hopping sequence in a TDMA or CDMA system.
Abstract:
A method for determining the position of a mobile radio telephone in a satellite communication system is disclosed. First, a mobile radio telephone scans a plurality of paging channels and measures the signal strength of the paging channels. The mobile radio telephone then selects the paging channels with the strongest signal strength and decodes the information broadcasted on the selected channel. The information contained in the paging channel can include frequencies or timeslots of paging channels in surrounding spot beams. The mobile station then measures the signal strength of paging channels in surrounding spot beams and quantizes the measurements to determine a coarse position of the mobile radio telephone.
Abstract:
A method and apparatus for communicating with a plurality of ground terminals using a plurality of satellites transmitting time-division multiplexed signals are disclosed. First, a first satellite transmits to a first group of ground terminals using a first number of timeslots in a TDM frame period. In addition, the first satellite and a second satellite transmit in alternate TDM frames to a second group of ground terminals using a second number of timeslots in said TDM frame period. Finally, the second satellite transmits to a third group of ground terminals using a third number of timeslots in the TDM frame period.
Abstract:
A radiotelephone having an asymmetric hinge configuration includes a housing having a door member, a handset member, and an asymmetric hinge connected to the door and handset members for enabling rotation therebetween about an axis of rotation that is substantially perpendicular to a plane bisecting the door member but preventing axial translation therebetween. The radiotelephone further includes a radiotelephone transceiver and a microphone positioned within the housing. The microphone is located on the pivot axis. The asymmetric hinge is configured so that the door and handset members are rotatable between a closed position, in which the door member overlies the handset member, and an operative open position, in which the handset member and the door member define an angle of between about 100 and 160 degrees.
Abstract:
A battery transfer apparatus and method according to the present invention provides continuous battery power to a battery powered device while changing batteries. Battery power is provided to the battery powered device from a charged battery while a nearly discharged battery is removed from the battery powered device. Battery power is also provided to the battery powered device from the nearly discharged battery while the charged batery is inserted into the battery powered device. The nearly discharged battery may be prevented from draining power from the charged battery during the transfer operation. A battery charger and battery condition indicator may also be included.
Abstract:
An RF site link for communicating between a centralized switching system and a plurality of mobile communications RF base stations is disclosed. The RF site link includes a plurality of RF link devices connected to centralized switching equipment. The RF link devices transmit signals to and receive signals from the remote base stations over the same working channels that the base stations use to communicate with the mobile or portable radios within each of the base stations' areas of operation. An RF control link is provided to control the assignment of the working channels between the centralized switching equipment and each of the base stations within the system.
Abstract:
A radio telephone which is capable of switching between operating through a land based cellular network and an orbiting satellite system is disclosed. First antenna and radio frequency circuits receive transmitted signals from the land-based network and form first conditioned signals for subsequent numerical decoding. Second antenna and radio frequency circuits receive transmitted signals from the orbiting satellite system and form second condition signals for subsequent numerical decoding. Numerical decoders process either the first condition signals or the second conditioned signals to provide an automatic frequency control signal. Reference frequency oscillators controlled by the automatic frequency control signal provide a reference frequency signal. Radio frequency synthesizers using the reference frequency signal and having a frist output at a first programmable frequency connected to the first radio frequency circuits determine reception of a channel frequency of the land-based network and a second output at a second programmable frequency connected to the second radio frequency circuits determines reception of a channel frequency of the orbiting satellite system.
Abstract:
A cellular telephone includes a speaker, a microphone and voice channel establishing means for opening a voice channel between the cellular telephone and a source telephone requesting communications with the cellular telephone without opening the speaker and microphone. Thus, voice communications between the cellular telephone and the source telephone are prevented until a predetermined signal from the user of the cellular telephone is received. The cellular telephone also includes delayed speaker and microphone connecting means for receiving and processing data from the source telephone without opening the speaker and the microphone. The data may include the identity of the source telephone or a message which may be displayed for the user of the cellular telephone. Based upon the identity of the source telephone, the user of the cellular telephone may selectively ignore or respond to the request for communications, or may route the request to an automated answering device or another telephone.
Abstract:
A radio receiver for demodulating and equalizing digital information is disclosed. The receiver receives radio signals and processes the signals to produce data samples which are then stored. Reference values that model what the receiver should receive for various transmitted symbol sequence hypotheses are also stored. The receiver equalizes the received data using the stored reference values to produce symbol detection information, and updates the reference values based on the symbol detection information.
Abstract:
A communications satellite is disclosed which uses distributed multiplexing and demultiplexing so as to minimize the amount of cabling needed between deployable phased array panels and a central processor. Signals are distributed from the active array panels to a member of active antenna elements. Each active antenna element has at least a radiating element, a modulator and a sample and hold circuit for forming modulation waveforms.