摘要:
A system includes a radar antenna and a radar controller. The radar controller generates two narrowband radar signals, each narrowband radar signal having substantially constant frequency, the frequencies of the two narrowband radar signals differing from one another. The controller operates the radar antenna to transmit each of the generated narrowband radar signals as a transmitted signal, each transmitted signal being characterized by a transmitted power. The controller also measures a received power of received signals that are received by the radar antenna, each received signal including a portion of a corresponding one of the transmitted signals that was returned from an object or from a calibration surface at a known calibration range. A processor operating in accordance with programmed instructions calculates a range to the object on the basis of the transmitted and received powers.
摘要:
A system includes a radar antenna and a radar controller. The radar controller generates two narrowband radar signals, each narrowband radar signal having substantially constant frequency, the frequencies of the two narrowband radar signals differing from one another. The controller operates the radar antenna to transmit each of the generated narrowband radar signals as a transmitted signal, each transmitted signal being characterized by a transmitted power. The controller also measures a received power of received signals that are received by the radar antenna, each received signal including a portion of a corresponding one of the transmitted signals that was returned from an object or from a calibration surface at a known calibration range. A processor operating in accordance with programmed instructions calculates a range to the object on the basis of the transmitted and received powers.
摘要:
Multiple-configuration communication apparatus includes: a communication device (130) simultaneously maintaining at least a first and a second channel; a storage device (114, 116, 118) storing a plurality of communication configurations; and a configuration controller (120) determining a first time frame and during the first time frame, selecting a first communication configuration of the plurality of communication configurations and controlling the communication device to configure itself to the first communication configuration to at least one of transmit and receive information over the first channel, and determining a second time frame that is different from the first time frame and during the second time frame, selecting a second communication configuration of the plurality of communication configurations, and controlling the communication device to configure itself to the second communication configuration to at least one of transmit and receive information over the second channel.
摘要:
A communication band is divided into a plurality of allocation channels (202, 204, 206, 208). At least one allocation channel (204) is transferred to a transform domain. The behavior of the at least one allocation channel is monitored in the transform domain in order to derive a set of statistics. The set of statistics are used to determine a channel category for the at least one allocation channel.
摘要:
A method and apparatus to adaptively puncture bits within QAM modulated data symbols transmitted in a communication system in order to effect a signaling channel. The method and apparatus utilize inherent characteristics of a particular mapping scheme for the QAM constellation to selectively puncture particular bits within a data symbol with signaling information and predetermined binary values to selectively increase the log-likelihood ratio gains of those particular bits punctured with the signaling information. The log-likelihood ratios are used to obtain the signaling information and, thus, increasing the gain of the log-likelihood ratios affords greater reliability for the signaling information without increasing the required system resources.
摘要:
A method and apparatus to efficiently calculate log-likelihood ratios for each bit within M-ary QAM modulated symbols transmitted in a communication system. The method and apparatus utilize characteristics of square Karnaugh mapping of the QAM symbol constellation in order to reduce the number of distance calculations needed to determine the log-likelihood ratios for each of the bits within a demodulated symbol. The reduction in the number of calculations affords significant reduction in the time needed to determine log-likelihood ratios, especially for higher order M-ary QAM systems.
摘要:
A current mode of operation is provided to a Walsh spreader (203), and based on the current mode of operation, the Walsh spreader (203) either varies a Walsh code at a symbol rate, or holds the Walsh code constant. During multi-carrier transmission a first symbol within a data stream (210) is spread with a first Walsh code, while symbols immediately preceding and following the first symbol are spread by a another, differing Walsh code. The sequence of Walsh codes exiting the spreader (201) is further scrambled by a pair of Pseudo-Noise (PN) codes (224) that are held constant for three Walsh code periods during multi-carrier transmission, and are not held constant during direct-spread transmission.
摘要:
A transmitter (300) comprises summers (301-307, 3178-319), and mixers (309-315, 333). During multi-carrier transmission, multiple I and Q components enter the transmitter. I.sub.1 is summed with I.sub.3, Q.sub.3 is subtracted from Q.sub.1, Q.sub.1 is added to Q.sub.3, and I.sub.3 is subtracted from I.sub.1. The outputs of a first and a second summer (301, 305) enters a first and a second mixer (309, 313) where they are mixed by a cosine function. Similarly, the outputs of a third and a fourth summer (303, 307) enter a third and a fourth mixer (311, 315) where they are mixed by a sine function. The output from first and the second mixer (309, 311) enter a first summer (317) where they are summed along with the I.sub.2 component. The output from the third and the fourth mixer (313, 315) enters a second summer (319) where they are summed along with the Q.sub.2 component.
摘要:
One or more vehicle communication systems associated with one or more vehicles may be activated. The one or more vehicles may, for example, include a gateway vehicle. A backhaul connection between a vehicle communication system associated with the gateway vehicle and a cellular infrastructure may be established. Signals from the cellular infrastructure may be received at the vehicle communication system associated with gateway vehicle. Using the vehicle communication system associated with the gateway vehicle, the signals received from the cellular infrastructure may be transmitted. Signals from one or more mobile devices may be received using the vehicle communication system associated with the gateway vehicle. The signals received from the one or more mobile devices may be transmitted to the cellular infrastructure using the vehicle communication system associated with the gateway vehicle.
摘要:
A transmitting device (100) transmits a first packet, comprising a second encryption vector, that is encrypted using a first encryption vector. The transmitting device transmits a second packet that is encrypted using the second encryption vector if an acknowledgement message is received within a predetermined time after transmitting the first packet; otherwise, the first packet is re-transmitted. Upon receipt of the first packet, a receiving device (102) decrypts the first packet using the first encryption vector and transmits the acknowledgement message. Upon receipt of the second packet; the receiving device attempts to decrypt a portion of the second packet using the first and second encryption vectors. If the portion of the second packet was successfully decrypted using the first encryption vector, the receiving device re-transmits the acknowledgement message for the first packet; otherwise, it transmits an acknowledgement message for the second packet.