Abstract:
In a time-division multiple-access TDMA communication system communication between a hub and a substantial number of mobile terminals is conducted over a plurality of channel groups. Load balancing toward a substantially uniform distribution of traffic loads among the channel groups is implemented by sharing control of the number of mobile terminals logged into each channel group between the hub and the mobile terminals. At login time, each mobile terminal selects the optimum channel group based on a channel group congestion factor broadcast on the forward TDM channel of each respective channel group. In addition, the hub has the ability to move a desired number of the mobile terminals from one to another channel group, based on information communicated in a network management service packet. The mobile terminals initiate moves based on statistical selection of mobile terminals using the communicated information.
Abstract:
A plural-differential phase shift keying (PDPSK) communication system has a transmitter (22) for encoding digital data as plural differentials of phase between successive pairs of channel symbols of a carrier, and a receiver (24) with a plurality of phase differential detectors (32, 48) connected in cascade for determining the plural differentials of phase of the incoming signals to achieve a bit error rate independent of frequency offsets and thereby an improved rate of signal acquisition.
Abstract:
A wireless communication system using a fractionated LEO satellite, wherein a combination of MIMO and geographic beamforming are used for radio access, and wherein the channel coefficient vectors are adaptively extrapolated in time and frequency to reduce the pilot signal density.
Abstract:
Methods and systems for low earth orbit satellite communications, utilizing fractionated satellites and constellations with large baselines. The latter, combined with spatial multiplexing protocols, provides access to user equipment on the ground with much greater spatial resolution than hitherto possible. Methods include overcoming the problem posed by the round-trip delay of satellite links when adaptive, downlink, beamforming is attempted in Frequency Division Duplex (FDD) systems. Methods include using of uplink and downlink pilot signals which eliminate the need for controlling the physical integrity of the fractionated satellite through an electromechanical servo-control system in space.
Abstract:
A Frequency Division Duplex (FDD) wireless terminal includes spaced-apart antennas that are configured to transmit over a return link and to receive over a forward link that is spaced apart from the return link in frequency. The FDD wireless terminal is configured to selectively refrain from transmitting over the return link from at least one of the spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the spaced-apart antennas of the FDD wireless terminal, that are caused, for example, by blocking appendages of a user of the wireless terminal. Related methods are also described.
Abstract:
A method/system of wireless payment of parking fees for a vehicle, applicable to both open street and closed garage parking, wherein the user and checker experiences are enhanced relative to the prior art by a number of means, including: autonomous sensing of the user's/vehicle's location and allowing the user to correct the indicated location if required; enabling a handset to automatically sense the ID of the vehicle in which it is located; enabling rapid and facile enforcement by providing the Checker with information about the location, parking session status and other attributes of parked vehicles and displaying the information on a portable terminal in a manner facilitating rapid validation; and further facilitating the identification of vehicles with expired sessions by a method/system of RF interrogation involving RF tags located in/on the vehicles and the checking terminal querying the RF tags.
Abstract:
In a deblocking operation, pixel values within a first block of pixels are compared, and pixel values in the first block are also compared to pixel values in a second block of pixels that is adjacent to the first block. Based on the results of the comparisons, a digital deblocking filter and a region of interest can be selected, where the region of interest identifies a number of pixels in the first block and a number of pixels in the second block to which the selected filter is to be applied.
Abstract:
First radio signals are received by a first satellite, the received first radio signals including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the first source and an interfering signal transmitted from a second source using the frequency assigned to the first source. The first radio signals are combined based on a first performance criterion to generate a first output signal. Second radio signals are received by a second satellite, the received second radio signals including a measure of the desired signal. The second radio signals are combined based on a second performance criterion to produce a second output signal. The first and second output signals are combined to generate an estimate of the desired satellite uplink signal.
Abstract:
In some embodiments, a satellite communications network dynamically regulates carrier assignment for bidirectional communications between a satellite and radioterminals. The satellite communications network includes a resource manager that regulates the carrier assignments by selecting among a plurality of FDD return subcarriers, with potentially different subcarrier bandwidths and supporting different radio access technologies, within at least one FDD return carrier grouping for coupling to a selected one of a plurality of FDD forward carriers, and by controlling the satellite network to receive communications from the radioterminal on the selected FDD return subcarrier and to transmit communications to the radioterminal on the selected FDD forward carrier.
Abstract:
A processor for use in a satellite communications system includes a selector that is configured to select a subset of a plurality of spatially diverse satellite signals based upon a location of a radioterminal. The processor further includes a signal processor that is configured to detect a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse satellite signals. The respective spatially diverse satellite signals may include respective signals corresponding to respective antenna elements of a satellite. The selector and the signal processor may be ground based.