Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: A beam control subsystem (200, FIG. 2) provides acquisition, synchronization, and traffic beams (142, FIG. 1) to communication devices (130) within a footprint (144) of a system node (110), where each beam comprises a set of beamlets (140). The subsystem (200, FIG. 2) first acquires (302, FIG. 3) and synchronizes (304, FIG. 3 and FIG. 6) with each communication device. Acquisition involves selecting (402, 416, FIG. 4) and combining (404) sets of beamlets (506, 510, FIG. 5), and determining whether any devices within the sets are attempting to acquire the system. If so, synchronization is performed by varying (604, FIG. 6) beamlet weighting coefficients to find, based on modem feedback, a combination of coefficients that yields a maximum signal-to-interference+noise ratio for multiple users within a beam. The communication device is then handed off (612, 614) to a traffic beam. The subsystem (200) continues, based on modem feedback, to adapt (802, 804, FIG.

Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: In a code division multiplexed system, a subscriber unit (260, FIG. 1), which includes a pseudonoise code generator (70), is synchronized with the pseudonoise code generator (220) of a communications node (200). Synchronization between the pseudonoise code generators (70, 220) is achieved through measuring the time delay of a signal transmitted from the communications node (200) to the subscriber unit (260) and advancing the code generator of the subscriber unit in accordance with the time delay. This permits transmissions from the subscriber unit (260) to be received synchronously at the satellite. The synchronization is maintained through the periodic transmission from the communications node (200) to the subscriber unit (260) of a message which commands the subscriber unit (260) to adjust the timing of its pseudonoise code generator. The resulting synchronous code division multiplexed system offers increased capacity over conventional systems.

Abstract: A phase domain multiplexed communication system generates N carrier frequencies each with a unique phase according to a selected orthogonal vector containing N elements. A subscriber information signal is first divided through a signal divider (215, FIG. 6). Each divided signal is then upconverted through a mixer (220) and phase shifted according to the selected orthogonal vector. The resulting signal is then combined through a summing element (250) and transmitted. At a receiver, the incoming signal is coupled to a signal divider (315, FIG. 7) where the signal is divided into N signal components. Each signal component is downconverted and phase shifted so that the transmitted subscriber information can be extracted at a summing element (350). At the summing element (350) the desired subscriber signal components add in-phase while the signal components corresponding to other subscribers add out-of-phase.

Abstract: The invention describes a method and system for channelization through the application of a weighted chirp pulse. The impulse response of a desired filter weighting is applied to the output of a chirp pulse generator (FIG. 1, 150). The resulting weighted chirp pulse is then applied to the a first columnar Bragg cell (80) while an unweighted chirp pulse is applied to a second columnar Bragg cell (90). A modulated energy beam (55) is then allowed to pass through both Bragg cells. The resultant spatially dispersed energy beam (95) is then applied to lens (120) and projected onto a detector array (130). The detector array (130) then extracts the subscriber transmitted information from the projected interference pattern.

Abstract: A multichannel time shared demodulator (10) is implemented in an efficient ASIC architecture that provides routing-of user voice channels and access channels to a collection of time-shared processors for rapid signal detection, tracking and demodulation. The channels are routed in a random order and then processed by a time-shared symbol synchronization processor (18) for voice channels and a time-shared detection processor for access channels. The signals are over-sampled via a time-shared interpolation filter. The interpolation process yields a ten to one over sampling ration of all signals. A synchronized clock is used to choose the phases of the interpolation filter outputs.

Abstract: Signal routing from origination nodes (210) to destination nodes (250) in a spread spectrum communication system (100) is provided using spread spectrum routing codes. Origination nodes (210) and destination nodes (250) are identified using specific codes. Signal routes from origination nodes (210) to destination nodes (250) are determined in terms of multi-level paths. Different codes are used to identify the different path levels. Data that is to be sent to a particular user located at a destination node is first spread using the destination code for that destination node. This spread spectrum signal is spread a second time using a first-level path code. In addition, the data can be spread a third time using a second-level path code. During the transmission of the spread data decoding processes are performed and the decoded data is routed based on the results of these decoding processes.