摘要:
An electronic transmitter transmits multiple digital input signals simultaneously by including an encoding circuit, a digital combiner circuit, and a modulator circuit. The encoding circuit encodes each of the digital input signals as a sequence of "1" and "0" chips with all of the chip sequences being synchronized in parallel; the digital combiner circuit generates a signed multi-bit digital signal which indicates the number of "1" chips minus the number of "0" chips that concurrently occur in the synchronized chip sequences; and, the modulator circuit generates a sinusoidal analog signal with a phase and a peak amplitude that respectively indicate the sign and magnitude of the signed multi-bit digital signal.
摘要:
The present invention relates to a towed wireless network communications subsystem for use in flight by a towing aircraft. The towed wireless network communications subsystem includes an aerodynamic enclosure having a tether attachment and configured to be towed by the towing aircraft. A directional antenna is disposed on the aerodynamic enclosure and is capable of forming one or more directional communications beams within a wireless network. A communications device is disposed in the aerodynamic enclosure and is coupled to the directional antenna(s). The communications device is configured to relay communications data between the towing aircraft and the wireless network.
摘要:
An apparatus and method for correlating a signal over a correlation interval while accommodating spreading code frequency offset is described. In one embodiment, the apparatus includes a plurality of correlators, where each correlator forms a correlation result corresponding to a unique code frequency offset hypothesis. Each correlator selects samples from a tapped delay line at a tap position moved along the delay line at a rate corresponding to the correlator unique code frequency offset hypothesis.
摘要:
Entry of a terminal into a wireless communications network is facilitated for terminals which may operate in either frequency-division duplex or time-division duplex mode. Join request messages transmitted by the terminals include a duplex capability indicator defining a carrier frequency which can be used to response to the terminals.
摘要:
An emergency locating system can include emergency transceivers and rescue transceivers. The emergency transceivers can be capable of repeat transmission of a distress message using a variable power level and variable spreading factor. A receive transceiver can be capable of receiving the distress messages and sending a confirmation message to the emergency transceiver. The emergency transceiver can be capable of receiving the confirmation message and terminating transmission of the distress message.
摘要:
A method for partitioning communication resource among multiple users partitions a portion of an available communication resource into a series of time-frequency slots, and allows multiple users to transmit in one of at least two available modes within a time-frequency slot. Preferably, one mode is time division of the time-frequency slot into time sub-slots, and another mode is code division of the time-frequency slot according to different spreading codes that spread an individual user's signal only within the subject time-frequency slot. Further details as to pilot signals, guard intervals, and payloads are described.
摘要:
In an aspect of the invention, a method is performed in a transceiver for adaptive power amplifier linearization in time division duplex communication systems. The method comprises, in response to a first condition, performing, using a feedback signal generated by receiving subsystem circuitry, adaptive power amplifier linearization on a signal to be transmitted. The method additionally comprises, in response to a second condition, performing operations in order to determine receive data from a received radio frequency (RF) signal. The operations use at least the receiving subsystem circuitry. In a further aspect of the present invention, a transceiver is disclosed.
摘要:
Disclosed is a method for operating a code division multiple access communications system, and a system that operates in accordance with the method. The method operates within a coverage area of a base station by assigning a set of spreading codes to individual ones of a plurality of subscriber stations and then, during transmissions within the cell, by periodically hopping amongst spreading code within the set of spreading codes such that at any given time no two subscriber stations operate with the same spreading code. The set of spreading codes may include the all one's spreading code. The step of periodically hopping preferably changes from a currently used spreading code to a next spreading code at a symbol rate or at a multiple of the symbol rate. The set of spreading codes may be a hopped sub-set of a larger set of spreading codes, and in this case the method further operates to assign a non-hopped sub-set of the larger set of spreading codes to individual ones of the plurality of subscriber stations for use on a system access channel and/or on a system control channel or, more generally, for use on a non-traffic channel. The system may be a fixed data rate system or a variable data rate system. In the latter case the step of periodically hopping may change from a currently used spreading code to a next spreading code at the symbol rate, or at a multiple of the symbol rate of the lowest or the highest symbol rate users.
摘要:
A method is disclosed for operating a wireless communications system, such as a DS-CDMA communications system, by transmitting a waveform that includes a plurality of repeating frames each having x header training base symbols in a header training symbol field (TH) and y tail training base symbols in a tail training symbol field (TT). The frame is received and functions as one of a plurality of different types of frames depending on the content of at least TT. In the preferred embodiment the frame functions as one of a normal traffic frame, a termination frame, or a legacy frame providing backwards compatibility with another waveform. A given one of the frames includes four equal-size data fields separated by three equal-sized control fields, the header training symbol field (TH) and the tail training symbol field (TT).
摘要:
A CDMA communication system is provided in which bit rates are dynamically allocated by a single CDMA receiving station to a plurality of CDMA transmitting stations, all of which are intercoupled to each other over a CDMA channel and a feedback channel. Each CDMA transmitting station includes a control circuit which sends control signals on the CDMA channel in spaced apart time intervals which request respective bit rates on the CDMA channel; and, the CDMA receiving station includes a bit rate allocating circuit which receives and responds to the control signals by sending feedback messages over the feedback channel that address individual CDMA transmitting stations and grant respective bit rates to the addressed station. In one preferred embodiment, each transmitting station includes a data buffer which stores a time varying number of data bytes that are to be sent, and each transmitting station requests respective bit rates on the CDMA channel by including that number in the control signals.