Abstract:
Two satellite communications systems can use the same frequency or frequencies in geographically overlapping footprints, without creating undue interference in a given system that is caused by the same frequency signal(s) that is/are used by the other system. In particular, an aggregate Effective Isotropic Radiated Power (EIRP) of the radioterminals and/or ancillary terrestrial components of a second satellite communications system in the common footprint is sufficiently low, and/or the receive antenna gain of a first satellite communications system is sufficiently low compared to the receive antenna gain of the second satellite communications system, so as to increase an aggregate receiver noise that is seen by the first satellite system receivers by an amount that does not substantially change a Quality of Service (QoS) of the first satellite communications system.
Abstract:
A cellular communications system comprising a space based system comprising a first set of cells, and a ground based system comprising a second set of cells. The space and ground systems can optionally function substantially autonomously, with each using spectrum from at least one predetermined frequency band.
Abstract:
A wireless communications system includes a space-based component (SBC) and an ancillary terrestrial component (ATC) configured to communicate with radioterminals using a common satellite service link frequency band and respective first and second different sets of channel separation codes. The first and second sets of channel separation codes may include, for example, respective sets of scrambling codes, respective sets of frequency assignment codes, respective sets of channel assignment codes, respective sets of sub-channel assignment codes and/or respective sets of spreading codes.
Abstract:
A signal strength that is associated with a first wireless communications channel is detected. Electromagnetic energy is transmitted over the first wireless communications channel in response to the signal strength being sufficiently weak. A determination is made whether a handoff should be made to a second wireless communications channel having a signal that is weaker than a signal of the first wireless communications channel. Related systems and methods are described.
Abstract:
A radioterminal may include a transceiver, a hands-free interface, and a satellite/hands-free interlock. The transceiver may be configured for space-based communications and for terrestrial wireless communications. The satellite/hands-free interlock may be configured to prevent the transceiver from transmitting space-based communications unless the hands-free interface is activated. Related methods are also discussed.
Abstract:
Communications systems and/or methods are disclosed that can provide extreme privacy, cognitive radio capability, robustness to fading and interference, communications performance associated with M-ary orthonormal signaling and/or high multiple-access capacity. Embodiments can use spread-spectrum waveforms that are featureless, devoid of chipping and devoid of cyclostationary signatures, statistically indistinguishable from thermal noise and able to cognitively fit within any available frequency space (narrow-band, broad-band, contiguous, non-contiguous). Some embodiments maintain all desirable features of classical direct-sequence spread-spectrum communications while providing new dimensions that are important to communications systems. Embodiments of the invention can provide M-ary orthonormal signaling with chipless spread-spectrum waveforms to provide extreme covertness and privacy. Moreover, embodiments of the invention may be used to cognitively and covertly utilize spectrum resources at minimal impact to incumbent users. Further embodiments may be used to provide minimum interference, opportunistic, “white space spectrum” communications.
Abstract:
A satellite communications system includes a plurality of feeder link antennas, a primary satellite, and an auxiliary satellite. The feeder link antennas are substantially co-located relative to one another. The primary satellite is configured to receive information over a plurality of return service links from radioterminals, to communicate a first portion of the information over at least one return feeder link directly to a first one of the feeder link antennas, and to communicate a second portion of the information over at least one inter-satellite link. The auxiliary satellite is spaced apart from the primary satellite, and configured to receive the second portion of the information from the primary satellite via the at least one inter-satellite link, and to communicate the second portion of the information across at least one return feeder link to a second one of the feeder link antennas.
Abstract:
Space-based wireless radiotelephone communications are provided in a satellite footprint over a satellite radiotelephone frequency band. The satellite footprint is divided into satellite cells in which satellite radiotelephone frequencies of the satellite radiotelephone frequency band are spatially reused. At least one of the satellite radiotelephone frequencies that is assigned to a given satellite cell in the satellite footprint is terrestrially reused outside the given satellite cell. A radiation pattern of at least the given satellite cell is modified to reduce interference with the at least one of the satellite radiotelephone frequencies that is terrestrially reused outside the given satellite cell.
Abstract:
A wireless communications system includes a terrestrial network that is configured to receive wireless communications from radiotelephones over satellite band frequencies that are divided into channels that are separated by one of frequency or code (e.g., OFDMA or CDMA). The terrestrial network is also configured to transmit wireless communications to radiotelephones over satellite band frequencies that are divided into channels that are separated by a different one of frequency or code (e.g., CDM or OFDM). Related devices and methods are also disclosed.
Abstract:
Satellite communications methods include receiving communications signals including co-channel interference at a space-based component from a plurality of wireless terminals in a satellite footprint over a satellite frequency band and reducing interference in the communication signals by (a) performing co-channel interference reduction on the communications signals to generate a plurality of interference reduced signals and (b) performing multiple access interference cancellation on the interference reduced signals. An interference reducing detector for a satellite communications system includes an interference reducer configured to perform co-channel interference reduction on communications signals to generate a plurality of interference reduced signals, and a detector configured to perform multiple access interference cancellation on the interference reduced signals. Satellite communications systems and satellite gateways including interference reducing detectors are also disclosed.